Microorganism

Antonie Van Leeuwenhoek, 1998 Apr, 73(3), 223 - 8
Biochemical alterations in Bradyrhizobium sp USDA 3187 induced by the fungicide Mancozeb; Fabra A et al.; We have previously shown that fungicide Mancozeb causes a 50% decrease in Bradyhizobium sp USDA 3187 growth rate and affects the bacteria-root symbiotic interaction . In order to elucidate the fungicide toxicity mechanism we determined the effects of Mancozeb on cell chemical composition, glutathione (GSH) content (molecule involved in the detoxification process), glutathione S-transferase (GST) activity and on polyamine, exopolysaccharides, capsular polysaccharides and lipopolysaccharides . Mancozeb produced biochemical alterations in membrane composition, polysaccharides and polyamines . In spite of the increment of GSH content and GST activity, they are not enough to prevent the growth diminution.

J Neurosci, 1998 Nov 15, 18(22), 9238 - 44
A memory for extracellular Ca2+ by speeding recovery of P2X receptors from desensitization; Cook SP et al.; Nerve endings of nociceptors (pain-sensing neurons) express an unusual subtype of ATP-gated ion channel, the P2X3 receptor, that rapidly desensitizes (<100 msec) and slowly recovers (>20 min) . Here we show that Ca2+, or certain other polyvalent cations, binds to an extracellular site on rat sensory neurons and can increase current through P2X3 channels more than 10-fold . Importantly, Ca2+ facilitates P2X3 current to precisely the same level whether a transient Ca2+ change occurred just before or several minutes before activating the channels with ATP . This memory for past changes in Ca2+ is integrative in that a 90 sec Ca2+ stimulus delivered just before an ATP application has the same effect as an earlier series of three, separated 30 sec Ca2+ stimuli . These diverse phenomena are explained by a single mechanism: Ca2+ speeds recovery of P2X channels from desensitization . Recovery follows an exponential growth curve that depends on the duration, but not the timing, of changes in recovery rate . Modulation of desensitization underlies a well described short-term memory in bacteria, and it might be similarly used in the nervous system.

Infect Control Hosp Epidemiol, 1998 Oct, 19(10), 805 - 7
Economic consequences of hospital infections in a 1,000-bed university hospital in Norway; Andersen BM; Hospital infections were studied among 41,000 patients admitted to a 1,000-bed university hospital in Oslo, Norway . A prevalence rate of 8.5% in 1995 contributed to 14,500 days of extra stay in the hospital . The direct economic consequences of hospital infections was 40 to 50 million Norwegian kroner ($6-$7 million) . The extra direct cost per infected patient was 14,300 Norwegian kroner ($2,200) . Hospital infections are generating high extra costs and morbidity in countries with good general health care and with few problems with resistant bacteria.

Philos Trans R Soc Lond B Biol Sci, 1998 Sep 29, 353(1374), 1405 - 12
The ethylene-receptor family from Arabidopsis: structure and function; Bleecker AB et al.; The gaseous hormone ethylene regulates many aspects of plant growth and development . Ethylene is perceived by a family of high-affinity receptors typified by the ETR1 protein from Arabidopsis . The ETR1 gene codes for a protein which contains a hydrophobic N-terminal domain that binds ethylene and a C-terminal domain that is related in sequence to histidine kinase-response regulator two-component signal transducers found in bacteria . A structural model for the ethylene-binding domain is presented in which a Cu(I) ion is coordinated within membrane-spanning alpha-helices of the hydrophobic domain . It is proposed that binding of ethylene to the transition metal would induce a conformational change in the sensor domain that would be propagated to the cytoplasmic transmitter domain of the protein . A total of four additional genes that are related in sequence to ETR1 have been identified in Arabidopsis . Specific missense mutations in any one of the five genes leads to ethylene insensitivity in planta . Models for signal transduction that can account for the genetic dominance of these mutations are discussed.

Semin Immunol, 1998 Oct, 10(5), 373 - 81
Mast cells and basophils in innate immunity; Abraham SN et al.; Mast cells and basophils are primarily associated with the pathophysiology of allergic diseases . Considering that these cells have been preserved through evolution they must serve a valuable function . Intrinsically, mast cells are ideally placed and well endowed with inflammatory mediators to play a critical role in immune surveillance . Recent studies have shown that mast cells and basophils can bind various bacteria even in the absence of opsonizing antibodies . The resulting interaction caused release of a variety of inflammatory mediators and, in the case of mast cells, also uptake of bacteria . Among the mediators released by these inflammatory cells, TNF-alpha appears critical as it potentiates the early neutrophil responses to bacteria . Observations in mutant mice that are deficient in mast cells has provided further evidence for the specific role of mast cells in host defense against bacteria . We believe that there is now sufficient evidence (at least for mast cells) to propose a multi-faceted and significant role for these cells in the host's innate immune response to infectious agents .

Eur J Biochem, 1998 Oct 1, 257(1), 202 - 9
Stopped-flow kinetics of hydride transfer between nucleotides by recombinant domains of proton-translocating transhydrogenase; Venning JD et al.; Transhydrogenase catalyses the transfer of reducing equivalents between NAD(H) and NADP(H) coupled to proton translocation across the membranes of bacteria and mitochondria . The protein has a tridomain structure . Domains I and III protrude from the membrane (e.g . on the cytoplasmic side in bacteria) and domain II spans the membrane . Domain I has the binding site for NAD+/NADH, and domain III for NADP+/NADPH . We have separately purified recombinant forms of domains I and III from Rhodospirillum rubrum transhydrogenase . When the two recombinant proteins were mixed with substrates in the stopped-flow spectrophotometer, there was a biphasic burst of hydride transfer from NADPH to the NAD+ analogue, acetylpyridine adenine dinucleotide (AcPdAD+) . The burst, corresponding to a single turnover of domain III, precedes the onset of steady state, which is limited by very slow release of product NADP+ (k approximately 0.03 s(-1)) . Phase A of the burst (k approximately 600 s(-1)) probably arises from fast hydride transfer in complexes of domains I and III . Phase B (k approximately 10-50 s(-1)), which predominates when the concentration of domain I is less than that of domain III, probably results from dissociation of the domain I:III complexes and further association and turnover of domain I . Phases A and B were only weakly dependent on pH, and it is therefore unlikely that either the hydride transfer reaction, or conformational changes accompanying dissociation of the I:III complex, are directly coupled to proton binding or release . A comparison of the temperature dependences of AcPdAD+ reduction by {4B-2H}NADPH, and by {4B-1H}NADPH, during phase A shows that there may be a contribution from quantum mechanical tunnelling to the process of hydride transfer . Given that hydride transfer between the nucleotides is direct {Venning, J . D., Grimley, R . L., Bizouarn, T., Cotton, N . P . J . & Jackson, J . B . (1997) J . Biol . Chem . 272, 27535-27538}, this suggests very close proximity of the nicotinamide rings of the two nucleotides in the I:III complex.

Eur J Biochem, 1998 Oct 1, 257(1), 160 - 8
Purification and characterization of a flavoprotein involved in the degradation of epoxyalkanes by Xanthobacter Py2; Westphal AH et al.; Recently a newly discovered pyridine nucleotide-disulfide oxidoreductase was reported to be essential for the degradation of epoxyalkanes by the Xanthobacter Py2 {Swaving, J., De Bont, J . A . M., Westphal, A . & De Kok, A . (1996) J . Bacteriol . 178, 6644-6646} . The disulfide oxidoreductase has now been purified from propene-grown Xanthobacter Py2 . This enzyme (component II) is a NADPH-dependent FAD-containing homodimeric protein . The physiological substrate for this enzyme is unknown . The enzyme was active with the following dithiol substrates in decreasing order: 1,3-propanedithiol, reduced lipoamide and dithiothreitol, and inactive with glutathione and monothiols . In the reversed direction, only activity with 5,5'-dithiobis(2-nitrobenzoate) could be measured . Compared with other disulfide reductases it has a high activity with 5,5'-dithiobis(2-nitrobenzoate) and a low diaphorase and oxidase activity . Steady-state kinetic studies at pH 8.5 with 1,3-propanedithiol show that the enzyme operates by a ternary complex mechanism in the direction of NADP+ reduction . Anaerobic incubation of the enzyme with 1,3-propanedithiol resulted in slow reduction of the enzyme to yield the thiolate-FAD charge-transfer complex, the rate depending on the pH . At pH 7, where reduction was not detectable within 2 h, rapid mixing of NADP+ with the enzyme-propanedithiol mixture resulted in the formation of a complex between the reduced enzyme and NADP+ within the dead time of the instrument (5.6 ms) . This is followed by slow formation of NADPH, concomitant with the appearance of the flavin C(4a)-thiol adduct, as judged from the spectral changes . This suggests that the rate-limiting step is the transfer of a hydride ion from the half-reduced enzyme to NADP+ . Stopped-flow experiments involving reduction by NADPH show a biphasic behavior . The rapid formation (k(obs) = 40 s(-1)) of a transient intermediate with little absorption decrease at 460 nm and long wavelength absorption was followed by the slow formation (k(obs) = 4 s(-1)) of a species characterized as the thiolate-FAD charge-transfer complex with bound NADP+ . Some formation of the FAD C(4a)-thiol adduct was also observed . Photoreduction in the presence of deazaflavin results in rapid bleaching at 450 nm, followed by the slow formation of a stable semiquinone . Full reduction could not be achieved, either by photoreduction or with NADPH, and was incomplete even with dithionite or NADPH in the presence of arsenite . The results indicate a low redox potential of the FAD and a slow rate of electron transfer from the pyridine nucleotide to the redox active disulfide and vice versa . From a sequence alignment with other disulfide reductases, it appears that the active site His-Glu diad is absent in this enzyme . The kinetic and spectral features described above will be discussed in this context.

J Mol Evol, 1998 Nov, 47(5), 508 - 16
The root of the universal tree of life inferred from anciently duplicated genes encoding components of the protein-targeting machinery; Gribaldo S et al.; The key protein of the signal recognition particle (termed SRP54 for Eucarya and Ffh for Bacteria) and the protein (termed SRalpha for Eucarya and Ftsy for bacteria) involved in the recognition and binding of the ribosome SRP nascent polypeptide complex are the products of an ancient gene duplication that appears to predate the divergence of all extant taxa . The paralogy of the genes encoding the two proteins (both of which are GTP triphosphatases) is argued by obvious sequence similarities between the N-terminal half of SRP54(Ffh) and the C-terminal half of SRalpha(Ftsy) . This enables a universal phylogeny based on either protein to be rooted using the second protein as an outgroup . Phylogenetic trees inferred by various methods from an alignment (220 amino acid positions) of the shared SRP54(Ffh) and SRalpha(Ftsy) regions generate two reciprocally rooted universal trees corresponding to the two genes . The root of both trees is firmly positioned between Bacteria and Archaea/Eucarya, thus providing strong support for the notion (Iwabe et al . 1989; Gogarten et al . 1989) that the first bifurcation in the tree of life separated the lineage leading to Bacteria from a common ancestor to Archaea and Eucarya . None of the gene trees inferred from the two paralogues support a paraphyletic Archaea with the crenarchaeota as a sister group to Eucarya.

Appl Environ Microbiol, 1998 Nov, 64(11), 4530 - 2
Methanotrophs and methanogens in masonry
Kussmaul M, Wilimzig M, Bock E.
Methanotrophs were present in 48 of 225 stone samples which were removed from 19 historical buildings in Germany and Italy . The average cell number of methanotrophs was 20 CFU per g of stone, and their activities ranged between 11 and 42 pmol of CH4 g of stone-1 day-1 . Twelve strains of methane-oxidizing bacteria were isolated . They belonged to the type II methanotrophs of the genera Methylocystis, Methylosinus, and Methylobacterium . In masonry, growth substrates like methane or methanol are available in very low concentrations . To determine if methane could be produced by the stone at rates sufficient to support growth of methanotrophs, methane production by stone samples under nonoxic conditions was examined . Methane production of 0.07 to 215 nmol of CH4 g of stone-1 day-1 was detected in 23 of 47 stone samples examined . This indicated the presence of the so-called "mini-methane"-producing bacteria and/or methanogenic archaea . Methanotrophs occurred in nearly all samples which showed methane production . This finding indicated that methanotrophs depend on biogenic methane production in or on stone surfaces of historical buildings.

Appl Environ Microbiol, 1998 Nov, 64(11), 4522 - 9
Kinetic bias in estimates of coastal picoplankton community structure obtained by measurements of small-subunit rRNA gene PCR amplicon length heterogeneity
Suzuki M, Rappe MS, Giovannoni SJ.
Marine bacterioplankton diversity was examined by quantifying natural length variation in the 5' domain of small-subunit (SSU) rRNA genes (rDNA) amplified by PCR from a DNA sample from the Oregon coast . This new technique, length heterogeneity analysis by PCR (LH-PCR), determines the relative proportions of amplicons originating from different organisms by measuring the fluorescence emission of a labeled primer used in the amplification reaction . Relationships between the sizes of amplicons and gene phylogeny were predicted by an analysis of 366 SSU rDNA sequences from cultivated marine bacteria and from bacterial genes cloned directly from environmental samples . LH-PCR was used to compare the distribution of bacterioplankton SSU rDNAs from a coastal water sample with that of an SSU rDNA clone library prepared from the same sample and also to examine the distribution of genes in the PCR products from which the clone library was prepared . The analysis revealed that the relative frequencies of genes amplified from natural communities are highly reproducible for replicate sets of PCRs but that a bias possibly caused by the reannealing kinetics of product molecules can skew gene frequencies when PCR product concentrations exceed threshold values.

Gastroenterology, 1998 Nov, 115(5), 1113 - 22
Lack of correlation between Lewis antigen expression by Helicobacter pylori and gastric epithelial cells in infected patients; Taylor DE et al.; BACKGROUND & AIMS: Lewis antigens are expressed by both human gastric epithelial tissue and Helicobacter pylori . We examined Lewis antigens expressed by gastric epithelium and by H . pylori isolated from the corresponding biopsy tissue . METHODS: H . pylori Lewis expression was determined by enzyme immunoassays, and immunoelectron microscopy was used to confirm the Lewis antigens on some H . pylori cells and in some biopsy specimens . Histopathology using identical monoclonal antibodies specific for Lewis A, B, X, and Y antigens was used to detect these antigens in 24 gastric biopsy specimens . RESULTS: We identified Lewis Y in 100%, Lewis X and Lewis B in 95.8%, and Lewis A in 87.5% of biopsy specimens . In H . pylori, 87.5% expressed Lewis Y, 79.2% Lewis X, and 4.2% (one strain) Lewis B . No Lewis A was detected . Antibody specific for Lewis X labeled the bacteria and associated adhesion pedestal . The cagA gene was present in 92% of strains . CONCLUSIONS: There was no direct relationship between Lewis antigen expression by H . pylori and gastric epithelial cells in infected patients . Expression of Lewis X and Lewis Y by H . pylori suggests the possibility of their requirement for establishment and/or maintenance of infection . An immunoelectron micrograph of H . pylori interaction with the gastric epithelial adhesion pedestal suggests a tentative role for Lewis X in the adhesion process.

Appl Environ Microbiol, 1998 Nov, 64(11), 4246 - 54
PCR-ribotyping of Xenorhabdus and Photorhabdus isolates from the Caribbean region in relation to the taxonomy and geographic distribution of their nematode hosts; Fischer-Le Saux M et al.; The genetic diversity of symbiotic Xenorhabdus and Photorhabdus bacteria associated with entomopathogenic nematodes was examined by a restriction fragment length polymorphism analysis of PCR-amplified 16S rRNA genes (rDNAs) . A total of 117 strains were studied, most of which were isolated from the Caribbean basin after an exhaustive soil sampling . The collection consisted of 77 isolates recovered from entomopathogenic nematodes in 14 Caribbean islands and of 40 reference strains belonging to Xenorhabdus and Photorhabdus spp . collected at various localities worldwide . Thirty distinctive 16S rDNA genotypes were identified, and cluster analysis was used to distinguish the genus Xenorhabdus from the genus Photorhabdus . The genus Xenorhabdus appears more diverse than the genus Photorhabdus, and for both genera the bacterial genotype diversity is in congruence with the host-nematode taxonomy . The occurrence of symbiotic bacterial genotypes was related to the ecological distribution of host nematodes.

Antimicrob Agents Chemother, 1998 Nov, 42(11), 2923 - 31
The Epstein-Barr virus thymidine kinase does not phosphorylate ganciclovir or acyclovir and demonstrates a narrow substrate specificity compared to the herpes simplex virus type 1 thymidine kinase; Gustafson EA et al.; The Epstein-Barr virus (EBV) thymidine kinase (TK) was expressed in mammalian 143B TK- cells to investigate its substrate specificity . The herpes simplex virus type 1 (HSV-1) TK was similarly expressed for comparison . Both viral TKs conferred a TK+ phenotype on 143B TK- cells . The nucleoside analog ganciclovir (GCV) did not affect the growth of 143B EBV TK or 143B TK- cells but effectively killed 143B HSV-1 TK cells . Furthermore, lysates of 143B EBV TK cells could not phosphorylate GCV, which was confirmed by high-performance liquid chromatography . EBV TK, HSV-1 TK, and EBV TK N-, a truncated EBV TK missing 243 N-terminal amino acids, were purified as fusion proteins expressed in bacteria, and all had TK activity . In addition, EBV TK was observed to have a thymidylate kinase activity but could not phosphorylate GCV, acyclovir, or 2'-deoxycytidine . In competition assays, only nucleoside analogs of thymidine significantly inhibited thymidine phosphorylation by EBV TK, with the following rank order: 5-bromodeoxyuridine > zidovudine > stavudine > sorivudine . These results demonstrate that EBV TK substrate specificity is narrower than those of alphaherpesvirus TKs and that thymidine analogs may be the most suitable nucleoside antivirals to target the enzyme . Clinical implications for gammaherpesviruses are discussed.

Acta Gastroenterol Belg, 1998 Jul-Sep, 61(3), 350 - 1
Adverse events of HP eradication: long-term negative consequences of HP eradication; Koster ED; Two problems can be identified as possible long term negative consequences of HP eradication: diminished efficacy of acid-lowering drugs, and an accelerated development of GERD . It was shown that omeprazole produces a greater decrease in gastric acidity in subjects with H . pylori infection than in those who are H . pylori negative, and that omeprazole produces a smaller decrease in gastric acidity after cure of H . pylori . This effect persisted for at least one year after HP eradication . It is not limited to omeprazole, but can also be seen with the H2 receptor antagonist ranitidine . At least one proven mechanism involved in this phenomenon is the disappearance of the alkalinizing effect of ammonia, generated from urea by HP's urease, after eradication of the bacteria; other mechanisms may also be involved . HP eradication may therefore potentially hamper acid inhibitory treatment . It is unknown to what extent this is clinically relevant . Although one study did not observe a relation between H . pylori status and efficacy of omeprazole maintenance therapy for GERD, it cannot be excluded that some patients may need more potent or higher doses of acid-lowering medication after HP eradication . Three studies suggest that duodenal ulcer patients who were successfully treated with H . pylori eradication therapy, may be at increased risk to develop GERD . Labenz's study finds that the incidence of GERD may be double 3 years after eradication . The life-table analysis suggested that cure of the infection was associated with an increased risk of reflux oesophagitis during the first year after treatment, whereas later the incidence of reflux oesophagitis was similar in both groups . Patients who developed reflux oesophagitis after the cure had a more severe body gastritis before cure, gained weight more frequently after cure, and were predominantly men . There are no data on the fate of the oesophagus after HP eradication in patients with reflux oesophagitis . The data thus strongly suggest that there is a risk for developing reflux oesophagitis after HP eradication in patients with duodenal ulcer . It is unknown whether HP eradication in patients without duodenal ulcer also increases the risk for developing reflux oesophagitis.

Biochim Biophys Acta, 1998 Oct 23, 1425(2), 437 - 40
Cloning, characterization and expression of beta-N-acetylglucosaminidase gene from Streptomyces thermoviolaceus OPC-520(1); Tsujibo H et al.; The nagB gene encoding beta-N-acetylglucosaminidase from S . thermoviolaceus OPC-520 was cloned and sequenced . The nagB gene could encode a protein of 541 amino acids with a calculated molecular mass of 58274 . NagB revealed significant similarities to beta-N-acetylhexosaminidases and chitobiases from bacteria, which are classified into family 20 glycosyl hydrolases . NagB effectively hydrolyzed all of the chitin oligosaccharides from dimer to hexamer.

Arch Pharm (Weinheim), 1998 Sep, 331(9), 269 - 72
Synthesis and biological evaluation of a series of substituted pyrazolo{3,4-d}-1,2,3-triazoles and pyrazolo{3,4-d}oxazoles; Vicentini CB et al.; In view of the biological relevance of triazole-based heterocyclic structures as antifungal, antiviral, and antitumor agents, we have synthesized a series of substituted pyrazolo{3,4-d}-1,2,3-triazoles (2e-h, 2j, 4b) which we evaluated for their cytostatic and antiviral (HIV-1 included) activity and for their capability to inhibit the multiplication of various human pathogenic fungi and bacteria . Moreover, the biological activities of a few compounds, namely pyrazolo{3,4-d}oxazoles (3a-e) and pyrazolo{3,4-d}-1,2,3-triazoles (2a-d, 4a, 5), previously obtained by us but not investigated for their biological activity, were also studied . Only compounds 3a-e were endowed with a significative antiproliferative activity on the human lymphoblastoid cell line MT-4 cells . All pyrazole derivatives proved ineffective in protecting cell cultures against the HIV-1-induced cytopathogenicity, and none of the compounds was active against the bacteria and fungi tested.

J Biochem (Tokyo), 1998 Nov, 124(5), 869 - 75
Emerging roles of Dlg-like PDZ proteins in the organization of the NMDA-type glutamatergic synapse; Nagano T et al.; A group of proteins found at cell-cell junctions have a common structural domain, called PDZ-a stretch of 80-90 amino acid residues initially identified in the three proteins PSD-95, Dlg, and ZO-1 . This domain is found in various proteins from bacteria to mammals and is involved in protein-protein interaction . Recently, many proteins containing this domain were identified in the nervous system by molecular cloning and shown to interact with other synaptic proteins, including various transmitter receptors, ion channels, and signal transducers . These PDZ-containing proteins are mostly located near the synaptic membrane and are, therefore, speculated to transport associated proteins to the synapse and/or anchor them at the synaptic sites . Alternatively, as a single molecule often contains multiple PDZ domains that can interact with each other, it may cluster all these synaptic molecules and facilitate their signaling at synaptic sites . This review focuses on the best characterized PDZ-containing proteins that interact with N-methyl-D-aspartate (NMDA)-type glutamate receptors and discusses their functions in synaptic organization.

Histochem J, 1998 Aug, 30(8), 549 - 52
The modified Steiner stain: a new use for an old stain? Staining cytomegalovirus-infected cells in gastrointestinal biopsies; Saiz E et al.; The modified Steiner stain is a non-specific silver stain for identifying bacteria in formalin-fixed, paraffin-embedded tissues . The principle behind its use is that bacteria are first sensitized using uranyl nitrate solution, making them able to precipitate silver from a silver nitrate solution . It is used routinely for staining gastric biopsies to identify Helicobacter pylori . Upon staining a gastric biopsy from a patient with acquired immunodeficiency syndrome (AIDS) and cytomegalovirus gastritis, we recognized that this technique also stains the viral inclusions of cytomegalovirus-infected cells . We then proceeded to stain 43 consecutive cytomegalovirus-positive gastrointestinal biopsies from 33 immunocompromised patients based on positive cytomegalovirus immunohistochemistry (DAKO-cytomegalovirus monoclonal antibody, clones DDG9 and CCH2) . We also stained eight cytomegalovirus-infected, non-gastrointestinal tissues, including lung, adrenal gland, ovary, skin and neural tissue, to ensure that the stain was staining the cytomegalovirus-infected cells and not argyrophilic or argentaffin neuroendocrine cells of the gastrointestinal tract . In 40 of the 43 cytomegalovirus-infected gastrointestinal biopsies, we saw positive staining with the modified Steiner stain (93% sensitivity) . The cytomegalovirus-infected, non-gastrointestinal tissues all stained positively with the modified Steiner stain . Because the modified Steiner stain is frequently used to identify Helicobacter pylori in gastric biopsies, we propose that it be studied further for possible use either as a screen or as a confirmatory tool, or both, for cytomegalovirus inclusions in gastrointestinal biopsies.

Eur Heart J, 1998 Sep, 19(9), 1321 - 7
The prevalence of chronic Chlamydia pneumoniae infection as detected by polymerase chain reaction in pharyngeal samples from patients with ischaemic heart disease; Gabriel AS et al.; AIMS: Cross-sectional serological studies have suggested an association between ischaemic heart disease and infections from Chlamydia pneumoniae and Helicobacter pylori . We therefore sought to find out if patients with ischaemic heart disease had an increased prevalence of C . pneumoniae in the pharynx . As the course of the C . pneumoniae infection remains unclear, both acute and follow-up samples were taken and compared with antibody levels . METHODS AND RESULTS: We studied 282 patients with ischaemic heart disease . One hundred and two subjects without history or symptoms of ischaemic heart disease served as controls . Pharyngeal specimens for polymerase chain reaction detection of C . pneumoniae, and blood samples for C . pneumoniae and H . pylori antibody detection, were collected . In patients with positive polymerase chain reaction or C . pneumoniae IgA titres > or = 32, indicating current infection, convalescent samples were taken at least 6 weeks later . An immunofluorescent antigen detection test was used to confirm the presence of C . pneumoniae elementary bodies in specimens found to be polymerase chain reaction positive . The prevalence of positive polymerase chain reaction tests was 36% among patients and 22% among controls (P<0.05) . Forty-seven percent of patients with positive polymerase chain reaction remained positive in the convalescent test . Elevated C . pneumoniae IgG titres > or = 512 were found in 39% of patients and 26% of the controls (P<0.05) . IgA titres > or = 32 were found in 46% of the patients and 44% of the controls (ns) . Antibody titres remained largely unchanged at convalescent testing . Two patients and none of the controls had IgM titres > 16 . There was no link between positive H . pylori serology and positive C . pneumoniae polymerase chain reaction tests . CONCLUSIONS: The high prevalence and persistence of positive pharyngeal C . pneumoniae polymerase chain reaction and elevated antibody titres in patients with ischaemic heart disease indicate a chronic infection . The pharyngeal presence of C . pneumoniae might contribute to a low grade inflammatory activation or be a source for further spread of the bacteria to atherosclerotic vessels.

Toxicon, 1998 Nov, 36(11), 1683 - 92
From noxiustoxin to Shiva-3, a peptide toxic to the sporogonic development of Plasmodium berghei; Possani LD et al.; This communication reviews shortly the main structural and functional characteristics of Noxiustoxin, a 39 amino acid residue peptide, maintained closely packed by three-disulfide bridges and its effects on excitable membranes . Shiva-3, a cecropin like-peptide composed of 38 amino acid residues is also briefly reviewed . Its design and synthesis was made possible by the expertise gained through the work previously performed with Noxiustoxin . One of the most prominent functional characteristics of Shiva-3 is the toxic effect upon the sporogonic development of Plasmodium berghei (responsible for a murine version of malaria) . A synthetic Shiva-3 gene was constructed by recursive polymerase-chain reaction (PCR) methodology and expressed using the vector pGEX2T as a hybrid protein between the glutathione-S-transferase at the N-terminal and Shiva-3 in the C-terminal part of the hybrid . The recombinant protein kills bacteria and Plasmodium berghei . The future aim of this work is to produce a transgenic mosquito that carries the message for synthesis and excretion of Shiva-3 and similar peptides, in the midgut of mosquitoes, in an attempt to control the spreading of human malaria.

J Bacteriol, 1998 Nov, 180(21), 5567 - 73
Identification and recombinant expression of a Mycobacterium avium rhamnosyltransferase gene (rtfA) involved in glycopeptidolipid biosynthesis; Eckstein TM et al.; The Mycobacterium avium complex is a source of disseminated infections in patients with advanced AIDS . This group of mycobacteria is distinguished by the presence of highly antigenic, surface-exposed glycopeptidolipids, and these glycolipids possess variant oligosaccharide structures that are the chemical basis of the 28 distinct serovars of the M . avium complex . We previously described the ser2 gene cluster, encoding the synthesis of the haptenic oligosaccharide (2, 3-dimethylfucose-rhamnose-6-deoxytalose-) of the serovar 2-specific glycopeptidolipid, and revealed a locus (ser2A) encoding a putative rhamnosyltransferase . Sequencing of the ser2A locus demonstrated the presence of three open reading frames, two of which yielded significant homology to several glycosyltransferases, and the deduced amino acid sequences of these two putative glycosyltransferases had 63% identity . These two genes were expressed in Mycobacterium smegmatis, and the resulting recombinant glycopeptidolipids were characterized by thin-layer chromatography and gas chromatography-mass spectrometry . These analyses demonstrated that only one of these genes, termed rtfA, encoded the rhamnosyltransferase responsible for the transfer of rhamnose to 6-deoxytalose . The identification of rtfA will permit further evaluation of glycopeptidolipid biosynthesis and the construction of isogenic mutants of multiple M . avium complex serovars . Moreover, such mutants will help define the role of glycopeptidolipids in the intracellular survival of these bacteria.

Biochem Biophys Res Commun, 1998 Oct 29, 251(3), 920 - 5
Molecular cloning of rat klotho cDNA: markedly decreased expression of klotho by acute inflammatory stress; Ohyama Y et al.; We have recently identified a novel gene, termed klotho, that is involved in the suppression of several aging phenotypes . The gene encodes a membrane protein that shares sequence similarity with the beta-glucosidases of bacteria and plants . In this study, we isolated rat klotho cDNA and examined its tissue distribution in rats . The deduced amino acid sequence of rat Klotho protein was 1014 amino acids in length and 94 and 85% homologous to those of mouse and human Klotho proteins, respectively . Northern blot analysis using the rat klotho cDNA probe identified a single transcript of 5.2 kb in size expressed predominantly in the kidney, while RT-PCR detected low levels of expression also in the brain, lung, intestine, and ovaries . During development, klotho expression in the kidney was markedly augmented after birth . Chromosomal localization of rat klotho was mapped to 12q12 . Northern blot analysis showed that expression of klotho was markedly decreased by lipopolysaccharide (LPS) in vivo, suggesting that expression of klotho is affected by acute inflammatory stress . The present study leads to a better understanding of the physiologic and pathophysiologic roles of Klotho .

Microb Pathog, 1998 Sep, 25(3), 157 - 64
Outer membrane proteins of Bartonella henselae and their interaction with human endothelial cells; Burgess AW et al.; Members of the genus Bartonella are unique in that they are bacteria which cause proliferation of microvascular endothelial cells and neovascularization (angiogenesis) . The mechanisms by which Bartonella henselae causes these processes are unknown . Given the importance of surface-exposed determinants in the pathogenesis of many organisms, outer membrane proteins (OMPs) of B . henselae were identified . Enrichment of the outer membrane fraction of B . henselae by sarkosyl treatment of total membranes, together with radioiodination and biotinylation of intact organisms, suggest that at least nine proteins, with molecular weights of 28, 30, 35, 43, 58, 61, 79, 92 and 171 kDa, are located in the outer membrane . Triton X-100-extracted biotinylated human umbilical vein endothelial cell (HUVEC) surface proteins bound to the 43 kDa B . henselae OMP after B . henselae whole-cell lysates and sarkosyl-fractionated OMPs were separated by SDS-PAGE and transferred onto nylon . Biotinylated B . henselae surface proteins of 28, 32, 43, 52 and 58 kDa were shown to bind intact HUVEC, with the 43 kDa protein being the major adhesin . Preincubation of HUVEC with an increasing concentration (20 microg/ml to 4 mg/ml) of sarkosyl-fractionated unlabelled B . henselae outer membrane proteins inhibited the attachment of all identified HUVEC binding proteins . The identification of B . henselae OMPs, as well as adhesins, should provide a basis for further investigation of the role of adherence in the pathogenesis of B . henselae .

Environ Health Perspect, 1998 Oct, 106 Suppl 5, 1157 - 63
Contribution of reactive oxygen and nitrogen species to particulate-induced lung injury; Zhu S et al.; Recently, a second pathway for the generation of potential oxidants with the reactivity of the hydroxyl radical without the need for metal catalysis has been described . In response to various inflammatory stimuli, lung endothelial, alveolar, and airway epithelial cells, as well as activated alveolar macrophages, produce both nitric oxide (.NO) and superoxide anion radicals (O2.-) . .NO regulates pulmonary vascular and airway tone and plays an important role in lung host defense against various bacteria . However, .NO may be cytotoxic by inhibiting critical enzymes such as mitochondrial aconitase and ribonucleotide reductase, by S-nitrosolation of thiol groups, or by binding to their iron-sulfur centers . In addition, .NO reacts with O2.- at a near diffusion-limited rate to form the strong oxidant peroxynitrite (ONOO-), which can nitrate and oxidize key amino acids in various lung proteins such as surfactant protein A, and inhibit their functions . The presence of ONOO- in the lungs of patients with acute respiratory distress syndrome has been demonstrated by measuring levels of nitrotyrosine, the stable product of tyrosine nitration . Various studies have shown that inhalation or intratracheal instillation of various respirable mineral dusts or asbestos fibers increased levels of inducible nitric oxide synthase mRNA . In this presentation, we review the evidence for the upregulation of .NO in the lungs of animals exposed to mineral particulates and assess the contribution of reactive nitrogen species in the pathogenesis of the resultant lung injury.

Mol Gen Genet, 1998 Sep, 259(5), 491 - 503
The pea (Pisum sativum L.) genes sym33 and sym40 control infection thread formation and root nodule function; Tsyganov VE et al.; Two novel non-allelic mutants that were unable to fix nitrogen (Fix ) were obtained after EMS (ethyl methyl sulfonate) mutagenesis of pea (Pisum sativum L.) . Both mutants, SGEFix(-)-1) and SGEFix(-)-2, form two types of nodules: SGEFix(-)-1 forms numerous white and some pink nodules, while mutant SGEFix(-)-2 forms white nodules with a dark pit at the distal end and also some pinkish nodules . Both mutations are monogenic and recessive . In both lines the manifestation of the mutant phenotype is associated with the root genotype . White nodules of SGEFix(-)-1 are characterised by hypertrophied infection threads and infection droplets, mass endocytosis of bacteria, abnormal morphological differentiation of bacteroids, and premature degradation of nodule symbiotic structures . The structure of the pink nodules of SGEFix(-)-1 does not differ from that of the parental line, SGE . White nodules of SGEFix(-)-2 are characterised by "locked" infection threads surrounded with abnormally thick plant cell walls . In these nodules there is no endocytosis of bacteria into host-cell cytoplasm . The pinkish nodules of SGEFix(-)-2 are characterised by virtually undifferentiated bacteroids and premature degradation of nodule tissues . Thus, the novel pea symbiotic genes, synm40 and sym33, identified after complementation analysis in SGEFix(-)-1 and SGEFix(-)-2 lines, respectively, control early nodule developmental stages connected with infection thread formation and function.

Mol Gen Genet, 1998 Sep, 259(5), 475 - 83
StgR, a new Streptomyces alboniger member of the LysR family of transcriptional regulators; Tercero JA et al.; A 3240-bp DNA fragment, located next to the puromycin biosynthetic gene cluster of Streptomyces alboniger, contains three complete ORFs in the order: stgA, stgU and stgR . The transcriptional orientation of stgA is opposite to that of stgU and stgR . Each gene is expressed from its own promoter, although stgU and stgR can be cotranscribed . The deduced amino acid sequences of their products present similarities to a variety of pyridoxal-phosphate-dependent aspartate aminotransferases (StgA), several proteins of unknown function (StgU), and the LysR-type of transcriptional regulators (StgR) . In a delta stgR null mutant of S . alboniger, transcription of stgA and stgU is increased with respect to that in the wild type . In addition, in vivo experiments with promoter-probe plasmids indicated that in the delta stgR mutant, stgA- or stgU-promoter-dependent expression of the reporter gene was up to three-fold higher than in the wild type . Taken together, these results indicate that StgR is a LysR-type transcriptional repressor of both stgA and stgU.

Dis Aquat Organ, 1998 Sep 11, 34(1), 21 - 6
Performance of serum-free broth media for growth of Renibacterium salmoninarum; Starliper CE et al.; Growth of Renibacterium salmoninarum was compared in 14 different broth media; 13 serum-free, and 1 that contained newborn calf serum, KDM2+M . Supplementation with 1% v/v R . salmoninarum MCO4M metabolite was evaluated for 6 of the media that do not utilize it as part of their ingredients . Viable cells were enumerated on Days 10, 20, and 30 post inoculation to evaluate performance . The experiment was repeated 3 times using high, low, and medium (trials 1 to 3, respectively) cell concentrations as inoculum . In general there was no optimal medium and all performed well . The choice of which to employ depends on the ease of preparation and presence of certain ingredients that might affect subsequent assays . In trials 2 and 3, the pH was estimated using test papers at the same time as cells were counted . Maximum pH increase occurred with KDM2+M and those media containing charcoal . For most media, a simple pH determination could be used as a means to check that growth has occurred in a culture, particularly if charcoal was added directly to the media and a visual inspection could not be made to detect growth.

Acta Physiol Scand Suppl, 1998 Aug, 643, 257 - 64
Structure and function of the Na+/glucose cotransporter; Wright EM et al.; Cotransporters are a major class of membrane transport proteins that are responsible for the accumulation of nutrients, neurotransmitters, osmolytes and ions in cells from bacteria to man . The energy for solute accumulation comes from the proton and/or sodium electrochemical gradients that exist across cell membranes . A major problem in biology is how transport is coupled to these electrochemical potential gradients . The primary example of this class of membrane proteins is the intestinal brush border Na+/glucose cotransporter (SGLT1), first described by Bob Crane in 1960 . Over 35 members of the SGLT1 gene family have been identified in animal cells, yeast and bacteria, and all share a common core structure of 13 transmembrane (TM) helices . Electrophysiological techniques have been used to examine the function of several family members, chimeras and mutants expressed in heterologous systems such as Xenopus laevis oocytes . These have revealed that cotransporters are multi-functional proteins: they are responsible for 1) . uncoupled passive Na+ transport (Na+ uniport); 2) . down-hill water transport in the absence of substrate; 3) . Na+/substrate cotransport; and 4) . Na+/substrate/water cotransport . The sugar binding and translocation pathway is formed by 4 TM helices near the C-terminal of the protein, helices 10-13 . We propose that the N-terminal domains of SGLT1 are responsible for Na+ binding and/or translocation, and that Na+/glucose cotransport results from interactions between the N- and C-terminal domains of the protein.

Zentralbl Hyg Umweltmed, 1998 Sep, 201(3), 279 - 84
Persistence of infectious hepatitis A virus and its genome in artificial seawater; Arnal C et al.; The stability of the hepatitis A virus (HAV) genome detectable by RT-PCR in artificial sterile seawater seeded with HAV has been compared to that of HAV detectable in cell culture . The HAV genome was detectable by RT-PCR for 232 days while virus particles were detectable in cell culture for only 35 days . This difference in stability indicates that detection of the HAV genome by RT-PCR is not a reliable indicator of the survival of HAV detectable in cell cultures . However, before these results can be extrapolated to stability in natural seawater, the effect of additional elements in the natural environment, such as bacteria, fungi and suspended matter, on the stability of the HAV genome and cell culture infectious HAV particles, will have to be examined.

Toxicol Lett, 1998 Sep 15, 98(3), 147 - 53
Genotoxicity of the dust organic extract and its fractions derived from an aluminium electrolytic plant; Yumei W et al.; The dust derived from an aluminium electrolytic plant was collected on a filter, then extracted by mixed solvent of benzene, hexane and isopropanol (7/2/1, v/v) . The solvent-soluble components was separated into five fractions, namely organic acids, organic alkalis, aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and polar compounds . The genotoxicities of the dust organic extract and its five fractions were examined with Ames test, unscheduled DNA synthesis (UDS), micronucleus (MN) and sister-chromatid exchange (SCE) tests in human lymphocytes in vitro which involve the different test systems (bacteria and mammalian cells) and three genetic endpoints (gene mutation, chromosome aberration and DNA damage) . The results of four experiments indicated that the dust organic extract showed higher genotoxicity . Among the five fractions, three fractions, namely organic acids, polycyclic aromatic hydrocarbons and polar compounds had higher genotoxicity than others . The other fractions, organic alkalis and aliphatic hydrocarbons had no genotoxicity . According to this study, it is necessary to take effective measures to abate the dust and protect the environment and human health.

Dis Colon Rectum, 1998 Oct, 41(10), 1273 - 80
Effect of bowel preparation and a fiber-free liquid diet on expression of transforming growth factor and procollagen in colonic tissue preoperatively and postoperatively; Buckmire M et al.; PURPOSE: Dehiscence of colonic anastomoses is prevalent and potentially fatal . In an attempt to reduce the likelihood of anastomotic dehiscence, the colon is cleansed before surgery and fiber-free diets are prescribed postoperatively . However, fiber-free diets induce colonic atrophy and impair healing . This study was designed to investigate the effect of bowel preparation and postoperative fiber-free diet on the local gene expression of transforming growth factor-beta 1 and procollagen type I . METHODS: Four Sprague-Dawley rats underwent bowel preparation with a fiber-free liquid diet and polyethylene glycol in a balanced electrolyte solution for two days (fiber-free preoperative diet group), whereas four rats received standard chow with fiber (preoperative diet with fiber group) . On the third day tissue was obtained from the descending colon of each rat to assess the effect of bowel preparation . Forty additional rats had their bowels prepared and underwent transection of the descending colon and anastomosis . These rats were then randomly assigned to continue on the liquid diet (fiber-free postoperative diet group) or rat chow (postoperative diet with fiber group) . On postoperative days 3, 5, 6, 7, and 14, colonic tissue was obtained from the anastomosis and analyzed with the use of semiquantitative reverse transcriptase-polymerase chain reaction to examine the relative expression of transforming growth factor-beta 1 and procollagen type I genes normalized to that of a constitutive gene . RESULTS: There was a decrease in the expression of the transforming growth factor-beta 1 and the procollagen type I genes in the fiber-free preoperative diet group compared with the preoperative diet with fiber group; however, this difference only reached statistical significance for procollagen type I . Postoperatively, significant increases in the expression of the transforming growth factor-beta 1 and procollagen type I genes over baseline levels were observed around postoperative day 7 in both groups, which temporally correlates with active phases of collagen deposition in the wounded colon . Expression of the procollagen type I gene, however, was significantly decreased at this time in the fiber-free postoperative diet group compared with the postoperative diet with fiber group . CONCLUSION: Although necessary to reduce septic complications, preoperative bowel preparation has a detrimental effect on the expression of transforming growth factor-beta 1 and procollagen type I . A postoperative fiber-free liquid diet also may be detrimental to the expression of these transcripts in the bowel . Alternative methods for delivery of colonic fuels are needed to create a better environment for colonic healing while eliminating bacteria and bulk.

Nat Biotechnol, 1998 Oct, 16(10), 925 - 8
Development of transgenic yellow poplar for mercury phytoremediation; Rugh CL et al.; We examined the ability of yellow poplar (Liriodendron tulipifera) tissue cultures and plantlets to express modified mercuric reductase (merA) gene constructs . Mercury-resistant bacteria express merA to convert highly toxic, ionic mercury, Hg(II), to much less toxic, elemental mercury, Hg(O) . Expression of merA in transgenic plants might provide an ecologically compatible approach for the remediation of mercury pollution . Because the alteration of the bacterial merA gene sequence is necessary for high-level expression in Arabidopsis thaliana, yellow poplar proembryogenic masses (PEMs) were transformed with three modified merA constructs via microprojectile bombardment . Each construct was synthesized to have altered flanking regions with increasing amounts of modified coding sequence . All merA constructs conferred resistance to toxic, ionic mercury in independently transformed PEM colonies . Stability of merA transgene expression increased in parallel with the extent of gene coding sequence modification . Regenerated plantlets containing the most modified merA gene (merA18) germinated and grew vigorously in media containing normally toxic levels of ionic mercury . The merA18 plantlets released elemental mercury at approximately 10 times the rate of untransformed plantlets . These results indicate that plants expressing modified merA constructs may provide a means for the phytoremediation of mercury pollution.

Biospectroscopy, 1998, 4(5), 311 - 26
Orientation of the heme vinyl groups in the hydrogen sulfide-binding hemoglobin I from Lucina pectinata; Silfa E et al.; Hemoglobin I (HbI) from the claim Lucina pectinata is a unique heme protein that binds and transfers hydrogen sulfide (H2S) to a symbiotic bacteria . The metcyano, metaquo, carbon monoxy, oxy, and deoxy complexes of HbI were studies by resonance Raman (RR) spectroscopy, and the metacyano and carbon monoxy complexes were also studied by 1H-NMR . The results indicate a unique orientation of the heme 2-vinyl group relative to other heme proteins . The RR spectra of the HbICO, metHbICN, metHbIH2O, HbIO2 and deoxyHbI heme derivatives show a band at 1621 cm-1 and a shoulder at 1626 cm-1, indicative of an out-of-plane position for one of the vinyls relative to the other one . Spin-lattice relaxation properties of protons in the metHbICN complex also suggest a unique orientation for the heme 2-vinyl group of HbI . The longitudinal relaxation time (T1) for the 2-H alpha, 2-H beta c, and H beta t protons are 120 ms, 115 ms, and 135 ms, respectively . The data from both techniques suggest an out-of-plane and trans-oriented 2-vinyl group, and an in-plane and cis-oriented 4-vinyl group for the low-spin complexes of HbI . These results imply that the electron withdrawing character of the out-of-plane vinyl group contributes to the stability of the heme Fe+3 oxidation state, facilitates the binding of the H2S ligand, and promotes the stability of this ferric H2S complex.

Comp Biochem Physiol B Biochem Mol Biol, 1998 May, 120(1), 205 - 16
Pyruvate dehydrogenase E1 alpha isoform in rat testis: cDNA cloning, characterization, and biochemical comparison of the recombinant testis and liver enzymes; Jeng J et al.; Previous data indicated a tissue-specific regulation of mitochondrial pyruvate dehydrogenase (PDH) complex, especially in the brain and testis . The lack of biochemical data on the rat testis PDH limits comparative analysis between testis and liver enzymes . Therefore, we have isolated a cDNA clone encoding rat testis PDH E1 alpha isoform, determined its nucleotide sequence, studied the tissue-specific expression, and characterized the recombinant protein produced in bacteria, compared to the liver counterpart . Our cDNA clone (2.2 kb) contained the identical open reading frame (from nt 974 to 2149) with that previously reported (Cullingford et al., 1993 Biochim Biophys Acta 1216:149-153) but contained a long 5' untranslated region, which has little identity to the other clone . Northern blot confirmed testis-specific expression of this isoform . Genomic DNA analyses by PCR amplification suggested this clone is a gene product distinct from its X-linked somatic counterpart . Our biochemical and kinetic analyses revealed that the purified recombinant rat testis PDH E1 (containing both E1 alpha and E1 beta subunits) was enzymatically active and phosphorylated in vitro by purified PDH-kinase p48 or p45, similar to the recombinant human liver enzyme . Our current data thus indicate that the differential regulation of testis PDH observed in the animal model may result from differential modulation of PDH-kinase or -phosphatase in this tissue rather than the presence of functionally different PDH E1 subunit.

Stress, 1997 May, 1(3), 123 - 134
Mini-Review; Stress Genes: An Introductory Overview; Macario AJ et al.; Molecular sequence data, made available in the last 15 years or so, have led to the classification of living cells into three phylogenetic domains: Bacteria, Archaea, and Eucarya . All the organisms that have been tested belonging to either domain were capable of mounting a stress response with essentially the same characteristics, regardless of the stressor . The protagonists in the cell's stress response are the stress genes and their protein products . Some of the latter are molecular chaperones . Under physiological conditions, these chaperones aid other cellular proteins to fold properly and achieve a native -functional- configuration, and to translocate from the place of synthesis to the cell's locale in which they will operate . In a stressed cell, the stress proteins that are chaperones protect other molecules from denaturation and help those partially damaged to regain a functional configuration . Thus, cell death is avoided and recovery is enhanced . The study of stress genes and proteins has progressed considerably in organisms belonging to the domains Bacteria and Eucarya . Less is known about the archaeal stress genes . Here, research with an organism from the Archaea is discussed, focusing on the stress genes of the hsp70 (dnaK) locus . Future perspectives for basic and applied research within the health sciences and biotechnology industries are presented.

Eur J Oral Sci, 1998 Oct, 106(5), 938 - 44
Adherence of Porphyromonas gingivalis to epithelial cells: analysis by flow cytometry; Huard-Delcourt A et al.; Porphyromonas gingivalis, implicated in the pathogenesis of periodontitis, can adhere to epithelial cells and gingival fibroblasts . This study employed flow cytometry to evaluate the adherence of P . gingivalis to epithelial cells under various conditions . The cell lines SK-MES and KB were used in the first experiments . The P . gingivalis strains employed were ATCC 33277, ATCC 49417 and W83 . Different adherence conditions were tested (contact time, bacteria/cell ratio, contact temperature) . In later experiments, adherence of P . gingivalis to human gingival epithelial cells (GEC) obtained by explant was studied under various conditions . Results showed that P . gingivalis had a high affinity for buccal keratinocytes compared with SK-MES . Adherence showed a level of saturation . The number of receptors may be limited for each epithelial cell line, and there may be more receptors for gingival keratinocytes . Depending on contact time, P . gingivalis showed a higher affinity for GEC, compared with the other two lines . P . gingivalis thus showed specific adherence for a host cell type from a site associated with periodontal disease.

Mol Microbiol, 1998 Oct, 30(1), 197 - 208
Intracellular multiplication and human macrophage killing by Legionella pneumophila are inhibited by conjugal components of IncQ plasmid RSF1010; Segal G et al.; Previously we have reported that Legionella pneumophila can mediate plasmid DNA transfer at a frequency of about 10(-3) transconjugants per donor and that this process is dependent on several icm genes . Here we characterize the icm-dependent conjugal ability of L . pneumophila and study its relationship to intracellular multiplication and host cell killing . We found that three icm genes and the RSF1010 mobA gene are completely required and that three icm genes and the RSF1010 mobC gene are partially required for conjugation . Conjugation occurred during lag phase and stopped when the cell number increased . Inhibition of transcription or translation in the donor had only a minor effect on conjugation frequency . These results suggest that stationary-phase bacteria contain a functional icm complex that can mediate conjugal DNA transfer and probably can initiate infection of human macrophages as well . We also found that a functional RSF1010 mobilization system inhibits intracellular multiplication and killing of human macrophages by L . pneumophila . The strongest inhibition was observed in icm insertion mutants complemented with wild-type icm genes on an RSF1010-derived plasmid . These results suggest that the conjugation substrate probably competes with the natural substrate of the L . pneumophila icm system for transfer outside the bacterial cell . We propose that the function of the L . pneumophila icm system is to transfer effector molecules to the host cell . These effector molecules may interact with components of the host cell that are involved in phagosome formation and fate.

Mol Microbiol, 1998 Oct, 30(1), 107 - 19
An essential GTP-binding protein functions as a regulator for differentiation in Streptomyces coelicolor; Okamoto S et al.; The Streptomyces coelicolor obg gene, which encodes a putative GTP-binding protein of the Obg/Gtp1 family, was characterized . The obg gene was essential for viability . Introduction of multiple copies of obg into wild-type S . coelicolor suppressed aerial mycelium formation . A single amino acid substitution at any of six positions was introduced into the GTP binding site of Obg, and the mutated proteins were expressed in wild-type cells . Obg(P168-->V) exerted a more accentuated suppressive effect on aerial mycelium formation than did the wild-type Obg protein . In contrast, Obg(G171-->A) accelerated the development of aerial mycelium . These results show that Obg protein functions as a pivotal regulator for the onset of cell differentiation through its ability to bind GTP . Western analysis revealed that expression of obg is regulated in a growth phase-dependent manner, indicating a sharp decrease just after onset of aerial mycelium development or at the end of vegetative growth . Obg was a membrane-bound protein as determined by immunoelectron microscopy.

Infect Immun, 1998 Nov, 66(11), 5534 - 6
Murine model of Bartonella henselae infection in the immunocompetent host; Regnath T et al.; Bartonella henselae is an emerging pathogen causing cat scratch disease, bacillary angiomatosis, and peliosis hepatis . Progress in understanding the pathogenesis of and the immune response to these infections has been limited by the lack of an animal model . Following intraperitoneal infection of C57BL/6 mice with B . henselae, organs were cleared of cultivatable bacteria within 6 days . In contrast, B . henselae DNA could be detected in liver tissue for at least 3 months . Liver tissue showed granulomatous inflammation reaching its highest degree of intensity during the fourth week of infection and resolving within 12 weeks postinfection . This mouse model is applicable to the study of the pathogenesis of B . henselae and the immune response to this pathogen in the immunocompetent host.

Infect Immun, 1998 Nov, 66(11), 5494 - 500
High-level expression of Chlamydia psittaci major outer membrane protein in COS cells and in skeletal muscles of turkeys; Vanrompay D et al.; The omp1 genes encoding the major outer membrane proteins (MOMPs) of avian Chlamydia psittaci serovar A and D strains were cloned and sequenced . The nucleotide sequences of the avian C . psittaci serovar A and D MOMP genes were found to be 98.9 and 87.8% identical, respectively, to that of the avian C . psittaci serovar A strain 6BC, 84.6 and 99.8% identical to that of the avian C . psittaci serovar D strain NJ1, 79.1 and 81.1% identical to that of the C . psittaci guinea pig inclusion conjunctivitis strain, 60.9 and 62.5% identical to that of the Chlamydia trachomatis L2 strain, and 57.5 and 60.4% identical to that of the Chlamydia pneumoniae IOL-207 strain . The serovar A or D MOMPs were cloned in the mammalian expression plasmid pcDNA1 . When pcDNA1/MOMP A or pcDNA1/MOMP D was introduced into COS7 cells, a 40-kDa protein that was identical in size, antigenicity, and electrophoretic mobility to native MOMP was produced . Recombinant MOMP (rMOMP) was located in the cytoplasm of transfected COS7 cells as well as in the plasma membrane and was immunoaccessible . Intramuscular administration of pcDNA1/MOMP in specific-pathogen-free turkeys resulted in local expression of rMOMP in its native conformation, after which anti-MOMP antibodies appeared in the serum.

Infect Immun, 1998 Nov, 66(11), 5477 - 84
SCID/NCr mice naturally infected with Helicobacter hepaticus develop progressive hepatitis, proliferative typhlitis, and colitis; Li X et al.; Hepatitis, proliferative typhlitis, and colitis were characterized in young adult and older SCID/NCr mice naturally infected with Helicobacter hepaticus . Liver lesions consisted of Kupffer, Ito, and oval cell hyperplasia along with multifocal to coalescing coagulative hepatocyte necrosis . Numerous Warthin-Starry-positive bacteria were observed in the parenchyma, and there were minimal to mild accumulations of monocytic cells and neutrophils . Proliferative typhlitis was characterized by moderate to marked mucosal epithelial cell hyperplasia with mild monocytic and neutrophilic infiltration . Minimal to mild colitis with mucosal epithelial cell hyperplasia of the colon was most marked in older mice . Comparable gastrointestinal lesions were not observed in uninfected control SCID/NCr mice . H . hepaticus was cultured from fetal viscera of 2 of 11 pups sampled late in gestation from infected SCID/NCr females, suggesting transplacental infection of H . hepaticus . As expected, most of the naturally infected SCID/NCr mice had no serum immunoglobulin G response against H . hepaticus . These findings contrast with those in infected immunocompetent A/JCr mice, which develop a significant immune response to H . hepaticus associated with prominent multifocal mononuclear cell infiltrates in the liver, with only rare bacteria observable at the periphery of inflammatory foci or in the biliary canaliculi . The results demonstrate that chronic inflammatory and proliferative lesions simultaneously affecting the liver, cecum, and colon are associated with natural infection of SCID/NCr mice with H . hepaticus and that lesions are progressive with age . Concurrent infection with H . hepaticus may confound studies that have been attributed to similar lesions due to other experimental manipulations of SCID/NCr mice.

Infect Immun, 1998 Nov, 66(11), 5113 - 8
Local immune responses to Chlamydia pneumoniae in the lungs of BALB/c mice during primary infection and reinfection; Penttila JM et al.; Cell-mediated immune (CMI) responses play a major role in protection as well as pathogenesis of many intracellular bacterial infections . In this study, we evaluated the infection kinetics and assessed histologically the lymphoid reactions and local, in vitro-restimulated CMI responses in lungs of BALB/c mice, during both primary infection and reinfection with Chlamydia pneumoniae . The primary challenge resulted in a self-restricted infection with elimination of culturable bacteria by day 27 after challenge . A mild lymphoid reaction characterized the pathology in the lungs . In vitro CMI responses consisted of a weak proliferative response and no secretion of gamma interferon (IFN-gamma) . The number of lung-derived mononuclear cells increased substantially during the primary infection; the largest relative increase was observed in B cells (B220(+)) . After reinfection, the number of lung-derived mononuclear cells increased further, and the response consisted mainly of T cells . The reinfection was characterized in vivo by significant protection from infection (fewer cultivable bacteria in the lungs for a shorter period of time) but increased local lymphoid reaction at the infection site . In vitro, as opposed to the response in naive mice, acquired immunity was characterized by a strongly Th1-biased (IFN-gamma) CMI response . These results suggest that repeated infections with C . pneumoniae may induce Th1-type responses with similar associated tissue reactions, as shown in C . trachomatis infection models.

J Eukaryot Microbiol, 1998 Sep-Oct, 45(5), 475 - 83
Molecular cloning and characterization of a superoxide dismutase (sod) gene in Pneumocystis carinii; Denis CM et al.; This work reports the isolation and characterization of a gene encoding a superoxide dismutase (SOD, EC.1.15.1.1.) from Pneumocystis carinii derived from rat . Sense and antisense oligonucleotides, deduced from SOD amino acid sequences from a wide variety of organisms, allowed amplification of a 669 bp genomic DNA fragment specific to this P . carinii . RACE-PCR was used to obtain the major part of the complementary DNA; the 5'- and 3'-genomic regions were obtained respectively from a Mbol subgenomic library and from an amplified fragment using oligonucleotides designed from the cDNA sequence . Comparison of genomic and cDNA sequences showed an open reading frame of 660 bp interrupted by seven small introns . The deduced amino acid sequence contained 220 residues . Protein sequence alignment demonstrated the highest homology (50.5% identity; 70.3% similarity) with Saccharomyces cerevisiae manganese-SOD (MnSOD) suggesting that P . carinii SOD belongs to the mitochondrial MnSOD group . A putative targeting peptide found at the 5'-end of the P . carinii SOD sequence also suggested its mitochondrial localization.

Extremophiles, 1998 Aug, 2(3), 359 - 66
Dietzia natronolimnaios sp . nov., a new member of the genus Dietzia isolated from an east African soda lake; Duckworth AW et al.; Two novel alkaliphilic aerobic organotrophic bacteria have been isolated from a moderately saline and alkaline East African soda lake . The new isolates grow at pH values between 6 and 10, with a pH optimum for growth of 9.0, and at a salt concentration between 0% and 10% (w/v) . Phylogenetic analysis based on 16S rDNA sequence shows that these isolates are very closely related (99.6% similarity) and are members of the monospecific genus Dietzia (98.8% and 98.7% similarity) . DNA/DNA hybridization revealed a relatedness of 83% between the two isolates, but only 8% between them and the type strain Dietzia maris . The G + C content as measured by thermal denaturation is 66.1 mol% . Phenotypic comparisons between D . maris and one isolate showed that they share very similar morphological and chemotaxonomic properties, but differ significantly in carbon source utilization profiles and halotolerance in alkaline medium . We propose a second species of this genus which we name Dietzia natronolimnaios (type strain 15LN1 = CBS 107.95).

Ostomy Wound Manage, 1998 Aug, 44(8), 44 - 52
Wound infection: a nurse's perspective; Fowler E; There is clinical uncertainty about the involvement of bacteria in open wounds . Frequently asked questions are: Is this wound infected? Should I culture the wound? How should I clean the wound? Do I need to use sterile technique when I perform local wound care? Using available science and common sense, a practical approach is proposed to answer these questions.

Wien Klin Wochenschr, 1998 Aug 21, 110(15), 511 - 20
Genesis of the uraemic syndrome: role of uraemic toxins; Horl WH; A variety of signs and symptoms constituting the uraemic syndrome may be related to the retention and accumulation of uraemic toxins . Several identified (and yet unidentified) uraemic toxins of low molecular weight are removed at least in part by dialysis therapy resulting in marked improvement of multiple organ dysfunctions and clinical symptoms . However, many abnormalities persist due to the high protein binding of several uraemic toxins or their high molecular weight associated with inadequate dialysis clearance . Moreover, carbamoylation of amino acids and proteins in uraemia as well as metabolic acidosis contribute to the functional and metabolic abnormalities of the uraemic state . Uraemia interferes with the function of polymor-phonuclear leukocytes by deranging their cellular biochemistry and biology . P-cresol and several newly identified granulocyte inhibitory proteins are responsible for reduced chemotaxis, oxidative activity, intracellular killing of bacteria, and glucose consumption by polymorphonuclear leukocytes . Hyperhomocysteinaemia is an independent risk factor for vascular disease in end-stage renal disease patients . Uraemic toxins interfere with calcitriol synthesis and concentration or activity of the calcitriol receptor . Advanced glycolysation end-products (AGEs) accumulate as a result of impaired renal excretion . AGE peptides may represent a modern-day version of "middle molecule" toxicity or uraemia . Of potential clinical importance are pentosidine-, imidazolone- and carboxymethyllysine-modifications of beta 2-microglobulin with respect to the development of uraemia associated amyloidosis . Several uraemic toxins also affect nitric oxide pathway . Particularly, dimethyl-L-arginine (ADMA) is a potent inhibitor of nitric oxide synthesis . Parathyroid hormone satisfies the strict criteria of an uraemic toxin . Many uraemic symptoms can be attributed to the excess of parathyroid hormone in patients with chronic renal failure . Finally, recent investigations indicate, that one or more dialyzable uraemic toxin(s) suppress(es) appetite and may contribute to malnutrition in uraemia.

Adv Exp Med Biol, 1998, 440, 355 - 9
Coronavirus nucleocapsid protein . RNA interactions; Cologna R et al.; The coronavirus nucleocapsid protein (N) is involved in encapsidation and packaging of viral RNA . In this study we investigated the ability of the bovine coronavirus (BCV) N protein to interact with RNA . Histidine-tagged BCV N (his-N) protein was expressed in bacteria . A filter binding assay was established to quantitatively measure the binding efficiency of purified his-N to different RNAs . The results indicate that bacterially expressed N bound both BCV and mouse hepatitis coronavirus (MHV) RNAs . Binding to in vitro generated BCV and MHV RNA transcripts was significantly higher than binding to a non-coronavirus RNA . Similar binding efficiencies were measured for a BCV defective genome, pDrep, and a transcript that contained the MHV packaging signal . Interestingly, the entire MHV DI, pMIDI-C, was bound at a higher efficiency than the packaging signal alone . This is one of the first reports to show that N interacts with the MHV packaging signal.

Acta Anat (Basel), 1998, 161(1-4), 7 - 17
Glycoproteins now and then: a personal account; Sharon N; The present article opens with a brief summary of the current knowledge of glycoproteins and their medical applications, as compared to the almost complete ignorance of these substances during the first half of the century . The author then relates how he became interested in carbohydrates in the 1950s, and subsequently in glycoproteins . He focuses on the identification of soybean agglutinin as the first known plant protein of this class, to which a widely occurring N-linked oligomannoside is attached, and continues with an account of his work on the coral tree lectin that contains plant-specific N-glycans . Moving at the same time deep into lectin research, he describes the discovery of the crucial role of bacterial surface lectins in the initiation of infectious diseases, thus providing the rationale for the current attempts to use carbohydrates for antiadhesion therapy of such diseases . The article ends with a survey of the author's contribution to spreading wide the knowledge of glycoproteins and of their great importance in biology and medicine.

Adv Exp Med Biol, 1998, 439, 249 - 67
Flavonoids as hormones . A perspective from an analysis of molecular fossils; Baker ME; Although for centuries plants have been known to have hormone-like actions in humans, the mechanism(s) by which plant-derived compounds act in humans is still being elucidated, a goal that has assumed more importance due to interest in the protective actions of fruits and vegetables in diseases such as cancer . Here I use the "molecular fossil record" of amino acid sequences of proteins involved in regulating the actions steroids, retinoids, thyroid hormone and prostaglandins to propose some mechanisms by which flavonoids in fruits and vegetables can have hormone-like actions in humans . I focus on: i) hormone receptors that bind to DNA and regulate gene transcription and ii) the enzymes that regulate the concentrations of these hormones . Comparative analyses of amino acid sequences show that nuclear receptors for steroids, retinoids, thyroid hormone and prostaglandins in humans and insects are descended from a common ancestor . Similar analyses of dehydrogenases that regulate the concentrations of steroids, retinoids and prostaglandins reveal strong sequence similarity to enzymes in plants, insects, fungi, and bacteria . The similarity is sufficient to suggest that some compounds that bind receptors or enzymes in invertebrates, plants or unicellular organisms may also bind to mammalian homologs that are involved in endocrine physiology . Among the phytochemicals that are candidates for such activity are flavonoids because they are involved in plant-insect and plant-bacteria interactions and have some structural and chemical similarities to steroids, retinoids, thyroid hormone, prostaglandins and fatty acids . These similarities and the kinship of human, plant, insect and bacterial proteins involved in signal transduction provide a conceptual framework for investigating flavonoids for hormone-like actions in humans . Understanding these modes of action may be useful in developing protocols for preventing hormone-dependent diseases such as breast and prostate cancer.

J Hist Dent, 1998 Jul, 46(2), 53 - 7
Leeuwenhoek and Vermeer, an association of genius; Shklar G; Antony van Leeuwenhoek, the inventor of the microscope and originator of the microscopic sciences, had an interesting association with the great Dutch artist, Vermeer, whose paintings were recently displayed in major exhibitions in Holland and the U.S.A . Leeuwenhoek is of particular interest to dental medicine for the first description of the oral bacteria and the first microscopic description of the stratified squamous epithelium of the oral mucosa, with its different layers from stratum germinativum to stratum corneum.

Clin Ter, 1998 Mar-Apr, 149(2), 151 - 4
{Sulbactam-ampicillin monotherapy in the ambulatory treatment of pneumonia . Results of mono-administration}; Natale F et al.; Since ampicillin, the parent drug of aminopenicillins, is hydrolyzed by penicillinase, it is normally used in association with sulbactam, a sodium penicillinate sulfone with potent inhibiting activity on type II, III, IV, and V beta-lactamases . The combination ampicillin-sulbactam has been found remarkably useful for the treatment of severe community pneumonia caused by bacteria resistant to ampicillin alone . Approximately 300 patients with community pneumonia of various degrees of severity have been treated with a single dose of 3-4 g ampicillin-sulbactam either diluted in normal saline or in dextrose solution, usually associated with methylprednisolone 20 mg or betametasone 8 mg (tapered) . As assessed by clinical and radiological findings, recovery has been obtained all cases.

J Infect Dis, 1998 Nov, 178(5), 1521 - 5
Helicobacter pylori urease significantly reduces opsonization by human complement; Rokita E et al.; The role of Helicobacter pylori urease in opsonization by human complement was investigated . H . pylori wild type strain N6 and isogenic mutants lacking either the large urease subunit (UreB) or an accessory urease protein (UreG) were incubated with different sera . C3b bound to the bacteria was measured by specific staining and flow cytometry . As compared with opsonization of N6 and the UreG-lacking mutant, opsonization of the UreB-lacking mutant was significantly increased after incubation with sera from both H . pylori uninfected (P<.001) or infected (P<.05) persons . However, when sera from uninfected persons were used, effective opsonization of this mutant proved to be dependent mainly on the classical pathway of complement activation . Irrespective of the serum used, opsonization values were very low after selective inactivation of the classical or the alternative pathway . Reduced opsonization of the urease-expressing strains could, to some extent, result from degradation of bound C3b.

J Infect Dis, 1998 Nov, 178(5), 1399 - 405
Vaccination of gnotobiotic piglets against Helicobacter pylori; Eaton KA et al.; To determine the effect of oral adjuvant-assisted and parenteral vaccination, germ-free piglets were vaccinated orally with and without labile toxin adjuvant or parenterally and challenged with viable Helicobacter pylori . All prechallenge vaccination regimens induced anti-H . pylori antibodies and suppressed bacterial colonization, but no vaccination regime completely prevented infection . Parenteral vaccination given after infection had no effect on bacterial colonization . Lymphocytic gastritis was present in all piglets challenged with live bacteria regardless of vaccination status . Neutrophilic gastritis was present in vaccinated challenged piglets but not in infected, unvaccinated piglets . Gastritis was not present in uninfected control piglets regardless of vaccination status . In gnotobiotic piglets, vaccination suppresses but does not prevent infection by H . pylori, and parenteral vaccination does not cure infected piglets . Vaccination does not ameliorate gastritis due to H . pylori in piglets but does induce neutrophilic gastric inflammation in some infected piglets.

Cardiology, 1998 Oct, 90(2), 83 - 8
Lack of evidence for a pathogenic role of Chlamydia pneumoniae and cytomegalovirus infection in coronary atheroma formation; Daus H et al.; Atherosclerotic cardiovascular disease is generally accepted to be the result of metabolic disturbances . However, recent studies have suggested an infectious agent, especially Chlamydia pneumoniae or cytomegalovirus, to be involved in the pathogenesis of atherosclerosis . Atherosclerotic plaque specimens obtained from patients with coronary disease either by balloon dilatation catheter (13 cases) or atherectomy (16 patients) were examined for the presence of C . pneumoniae and cytomegalovirus . Using two primer pairs for C . pneumoniae, two primer pairs for the identification of unknown bacteria and primer pairs for the detection of immediate early gene E2 and the late genomic region of cytomegalovirus, we were unable to detect the suspected agents . The absence of C . pneumoniae, other bacteria and CMV in coronary atheromas is against the hypothesis of a pathogenetic role of these agents in coronary atheroma formation in the patients studied.

Acta Radiol Suppl, 1998, 419, 7 - 35
The influence of radiographic contrast media on some granulocyte functions; Rasmussen F; Radiographic CM are used to change the X-ray absorption of tissue . They have been used since the 1930's and today four main types are available . All these CM are derived from one original structure: the 2,4,6 triiodobenzoic acid with the substituents in positions 1,2 and 5 as a carboxylic group or amides . According to the nature of the substituents and the number of aromatic rings, the four different types of CM can be identified . Three of the four types of CM are hyperosmolar, some of the ionic CM contain meglumine and all CM contain calcium disodium EDTA . To fulfil their role in host defence, circulatory PMN must adhere to endothelium of capillaries and venules adjacent to the inflammatory locus, migrate through the vessel wall to the area of inflammation, phagocytose opsonized bacteria, kill ingested organisms and, finally, inactivate their own toxic products to prevent damage to normal tissue . CM should be biologically inert, but many physiological and pathophysiological effects have been described . This review deals with the present knowledge about the influence of CM on PMN . This thesis presents results of the effects of the four main types of CM on PMN exocytosis of elastase and lactoferrin, adherence to nylon fibers, chemotaxis under agarose and phagocytosis of latex particles, as well after in vitro exposure of CM to PMN and after intravascular injection of CM . After in vitro exposure of CM to whole blood, a dose-dependent fall in lactoferrin and elastase concentration was observed, statistically significant for diatrizoate and ioxaglate at high concentrations . I.v . injection of iohexol or ioxaglate resulted in small, although statistical, decreases in lactoferrin concentration in plasma . No differences between the CM groups were seen . PMN adherence to nylon fibers after incubation of CM with whole blood or isolated PMNs was inhibited . The most inhibitive agents were the ionic CM diatrizoate and ioxaglate . The meglumine ion was found to contribute to the inhibitive effect of diatrizoate upon adherence . Following i.v . injection of iohexol or ioxaglate, increased numbers of PMNs, in combination with decreased adherence, were noted with ioxaglate, and the opposite with iohexol . Immediately after arteriography with iohexol and ioxaglate, a small increase of PMN count, in combination with decreased adherence, could be seen . An inhibition of adherence will result in a shift from the marginal to the circulatory pool of PMNs and thus an increase in PMN count . Although statistically significant the changes were minor . A pronounced increase in PMN count was seen 2-5 hours after arteriography in combination with a decrease in adherence . These changes may be due to a release of glucocorticoids from the adrenals in response to the procedure and/or the injection of CM . CMs do not act as chemoattractants . However, when CM are added to the chemoattractant N-fMLP in the under agarose assay, the number of PMNs migrating (density) was lowered, while the distance migrated by the leading front was not affected except for diatrizoate that almost abolished migration . When diatrizoate was added to PMNs, a dose-dependent inhibition was observed . Following i.v . injection of CM, no changes in PMN chemotaxis or changes in the chemoattractive potential of serum could be demonstrated compared to the baseline levels . The ability of PMNs to ingest latex particles after incubation with CM was inhibited in a dose-dependent way . The most inhibitive agents were diatrizoate and ioxaglate . A solution containing the same amount of disodium calcium EDTA as the CM solutions inhibited phagocytosis significantly, although less than the CM solution . Improved phagocytosis was observed in hyperosmolar environments due to NaCl or mannitol at osmolarities higher than 369 mOsm . I.v . injection of ioxaglate or iohexol inhibited the phagocytosis of latex particles by PMNs . The impairment was most pronounced immediately after the injection, and had almost returned to ba

Yakugaku Zasshi, 1998 Sep, 118(9), 415 - 22
{Inactivation and toxoiding of biologically-active components of Bordetella pertussis by tea catechins}; Watanabe M et al.; An ability of tea catechins known as agents for the disinfection to bacteria and viruses were tested on application for toxoiding biologically active components of Bordetella pertussis . The effects on the activities and antigenicity of filamentous hemagglutinin (FHA) and pertussis toxin (PT) were investigated . The activities of FHA and PT were inactivated by catechins at approximately 10(3) times lower dose (0.2 mM) compared with that of formalin . The activity of inactivated FHA was recovered by dialysis against Tris-HCl buffer, pH 8.0, containing glutathione or Tris-HCl buffer, pH 6.0 . But the activity of inactivated PT was not recovered . Antigenicity of catechin-treated antigens were investigated by immunization to mice . The sera from mice immunized by catechin-treated FHA or PT were contained antibody against not only catechin-treated but also non-treated FHA or PT . These results suggest that antigenicity of FHA or PT was not destroyed by the treatment with catechin . We prepared pertussis-component vaccines by treatment of several catechins on the condition that FHA or PT activity was not recovered . Higher efficacy were found on the vaccines made by treatment of epicatechin, epicatechin gallate, or epigallocatechin than those by formalin . The vaccine prepared by using epigallocatechin gallate had significant efficacy as well as that by formalin treated one . From these results, it is suggested that tea leaf catechins were effective agents for toxoiding of vaccine components.

Curr Biol, 1998 Oct 8, 8(20), 1129 - 32
Caspases and programmed cell death in the hypersensitive response of plants to pathogens; del Pozo O et al.; The hypersensitive response (HR) is induced by certain plant pathogens and involves programmed cell death (PCD) to restrict the spread of pathogens from the infection site {1} . Concurrent with the induction of cell death, the host activates a defense response {2} . The cell death associated with the HR in several plant-pathogen systems has morphological similarities to animal apoptosis {3,4}, which suggests that cell death mechanisms in plants and animals may share common components that lead to similar cellular events . Caspases are conserved cysteine proteases that regulate animal PCD {5}; caspase activity or an involvement of caspases in cell death has yet to be reported in plants . In this work, we investigated the participation of caspases in HR cell death . Caspase-specific peptide inhibitors, Ac-YVAD-CMK {6} and Ac-DEVD-CHO {7}, could abolish bacteria-induced plant PCD but did not significantly affect the induction of other aspects of HR, such as the expression of defense genes . This result confirmed our previous model that cell death can be uncoupled from defense gene activation during HR {8} . Caspase-like proteolytic activity was detected in tobacco tissues that were developing HR following infection with tobacco mosaic virus (TMV) . Our results provide evidence for the presence of caspase-like plant protease(s) that participate in HR cell death.

Biochemistry, 1998 Oct 20, 37(42), 14900 - 9
Triplet properties and interactions of the primary electron donor and antenna chromophores in membranes of Heliobacterium chlorum, studied with ADMR spectroscopy; Vrieze J et al.; The triplet states of antenna and reaction center bacteriochlorophyll (BChl) g in membranes of Heliobacterium chlorum were studied by optically detected magnetic resonance in zero magnetic field, using absorbance detection . A variety of triplet states was detected, which were all localized on single BChl g chromophores as concluded from a comparison with the triplet state of monomeric BChl g in organic solvents . With the aid of the microwave-induced absorbance difference spectra, we assign a triplet state with zero-field splitting parameters |D| = 727.5 and |E| = 254 . 5 MHz to that of the primary donor . The low |E| value indicates that the BChls of the primary donor are monoligated . The intensities of the zero-field transitions were strongly dependent on the redox state of the secondary electron acceptors . A triplet state with |D| = 690-705 MHz and |E| =230 MHz, present under all redox conditions, is associated with antenna BChl g absorbing at 814 nm . Its triplet yield was independent of the redox conditions; we conclude therefore that the antenna chromophores absorbing at 814 nm are not connected with the reaction center at cryogenic temperatures (1.2 K) . In addition, relatively strong signals were detected belonging to triplet states with |D| and |E| of 663-680 and 220-227 MHz, respectively, whose amplitudes were dependent on the redox conditions . Triplet states with these zero-field splitting parameters are located on antenna chromophores absorbing between 798-814 nm; their zero-field transitions and absorbance difference spectra indicate a considerable heterogeneity . The concentration of triplet states of antenna chromophores absorbing around 800 nm decreased markedly upon prolonged excitation at 1.2 K . This phenomenon is attributed to quenching of excitations on antenna pigments by stable charge separation in the closely connected reaction center, possibly involving a low-quantum yield menaquinone electron acceptor.

Am J Surg, 1998 Aug, 176(2A Suppl), 11S - 19S
The development and complications of diabetic foot ulcers; Laing P; Neuropathy and ischemia, two common complications of diabetes mellitus, are the primary underlying risk factors for the development of foot ulcers and their complications . The presence of symmetric distal polyneuropathy, encompassing motor, sensory, and autonomic involvement, is one of the most important factors in the development of diabetic foot ulcers . Perhaps one third of diabetic foot ulcers have a mixed neuropathic and ischemic etiology . Although neuropathy and ischemia are the primary predisposing factors in the formation of diabetic foot ulcers, an initiating factor, such as physical or mechanical stress, is required for an ulcer to develop . Ischemic ulcers develop as a result of low perfusion pressure in a foot with inadequate blood supply, whereas neuropathic ulcers result from higher pressures in a foot with adequate blood supply but loss of protective sensation . In addition to increasing the risk of ulceration, diabetes mellitus also increases the risk of infection by impairing the body's ability to eliminate bacteria . The processes by which ulcers develop are reviewed here.

Immunobiology, 1998 Aug, 199(2), 190 - 9
Ficolins and the fibrinogen-like domain; Lu J et al.; Ficolins are a group of proteins containing collagen-like and fibrinogen-like (FBG) sequences and they have a similar overall structure to C1q and the collectins . There are two types of ficolin in man: L-ficolin and M-ficolin . L-ficolin is synthesized in the liver and secreted into the plasma . It binds to several apparently unrelated structures including sugar residues and enhances phagocytosis of bound bacteria . M-ficolin is synthesized mainly in monocytes and is detected on the monocyte surface . The polypeptide sequences of ficolins, the collectins and C1q diverge mainly in their C-terminal globular regions which are, respectively, FBG domains, Ca(2+)-dependent carbohydrate recognition domains (C-type CRD), and collagen-related sequences . The FBG domain consists of 220-250 residues and is found in a number of proteins besides fibrinogen and ficolins . The crystal structure of the FBG domain has been characterized and the elucidation of its binding properties should provide essential insights into its role in ficolins and other proteins.

Avian Dis, 1998 Jul-Sep, 42(3), 613 - 7
Isolation of Georgia variant (Georgia isolate 1992) infectious bronchitis virus but not Ornithobacterium rhinotracheale from a Kentucky broiler complex; Erbeck DH et al.; Integrated broiler production operations in western Kentucky have been very successful . The reason for this success includes the fact that flocks are free of many endemic diseases for a period of time, often years, because birds are raised in virgin, disease-free territory . This case report documents that importation of birds from an area with endemic Georgia variant (GA-92) infectious bronchitis virus and Ornithobacterium rhinotracheale (ORT) bacterial infection resulted in introduction of GA-92, but not ORT, to Kentucky farms . As more broiler production units locate in western Kentucky, in the early phases of operation, they may not experience the "virgin territory," disease-free advantage.

Avian Dis, 1998 Jul-Sep, 42(3), 572 - 8
Vaccination of chickens against Ornithobacterium rhinotracheale infection; van Empel P et al.; Vaccination of young broilers with inactivated vaccines against experimental Ornithobacterium rhinotracheale challenge was found to be effective, but the results of vaccination were influenced, in a negative way, by the presence of maternal antibodies . The use of a strong adjuvant, such as mineral oil, in a bacterin was necessary to obtain good protection when maternal antibodies were present . Vaccination of broiler breeders resulted in high serologic responses and protection of their progeny against experimental O . rhinotracheale challenge up to an age of 4 wk . Vaccination of broilers with a live vaccine was found to be effective when the maternal antibody levels were low . A combination of vaccinating the breeders with a bacterin and their progeny with a live vaccine at approximately 3 wk of age seems to be the best way to protect broilers against O . rhinotracheale infection.

J Biomed Mater Res, 1998 Nov, 42(2), 272 - 7
The effect on immunocytes of anodic oxide titanium after hydrothermal treatment; Takebe J et al.; All dental root implants come in contact with the oral epithelium, and many complex factors are found to arise in this region . In order to perform a successful dental root implantation, it is necessary to clarify the interaction of the dental root implant material with the host defense mechanisms involved in the specific and nonspecific immune responses to many antigens in oral bacteria and their components . Recently, focusing on developing the dental root implant, the Nikon Corporation improved the surface characteristics of pure titanium even further by developing a hydroxyapatite (HA) layer formed on an anodic titanium oxide film containing Ca and P via hydrothermal treatment (SA treatment) . However, since little is known about the effect of SA-treated pure titanium (HA/Ti) on the defense mechanisms of the oral membrane epithelium, we investigated (1) the in vitro proliferation of murine splenic B lymphocytes on the surface of HA/Ti in the presence of three lipopolysaccharide (LPS) concentrations and (2) interleukin-1alpha (IL-1alpha) production by the reaction of human peripheral blood mononuclear cells (PBM cells) on the surface of HA/Ti under the same concentrations . After culture, murine splenic lymphocytes were measured by uptake of 3H-thymidine, and cytokine release (IL-1alpha) from PBM cells was measured by ELISA . Results showed that HA/Ti had hardly any effect on the LPS-induced proliferation of B lymphocytes and IL-1alpha production . In vitro investigations of the effects of HA/Ti on the LPS-induced proliferation of murine splenic B lymphocytes and IL-1alpha from PBM cells might be a useful way of elucidating the defense mechanism between implants and the oral epithelium.

J Histochem Cytochem, 1998 Nov, 46(11), 1243 - 8
Immunohistochemical analysis of the distribution of the human ATPase (hASNA-I) in normal tissues and its overexpression in breast adenomas and carcinomas; Kurdi-Haidar B et al.; Human ATPase (hASNA-I) is a novel human gene recently cloned on the basis of homology to the arsA gene of bacteria . Its protein product is an ATPase that is free in the cytoplasm and bound in the perinuclear area and nucleolus in human cells . We prepared the hASNA-I-specific 5G8 monoclonal antibody and used it to investigate the expression of hASNA-I in normal human tissues and breast cancers . hASNA-I was detected immunohistochemically only in the epithelial cells of the liver, kidney, and stomach wall, in the adrenal medulla, in the islet cells of the pancreas, in the red pulp of the spleen, and in cardiac and skeletal muscle . No staining was observed in the uterus, testis, lung, thyroid, cerebellum, and large intestine . Although no staining was also observed in normal breast tissue, all four cases of breast fibroadenomas and all 15 cases of either primary or metastatic breast carcinoma demonstrated increased staining . No embryological or functional common denominator is readily apparent . However, the increased expression in malignant breast cells is of particular interest with respect to the use of this antibody for screening of cytological specimens.

J Biol Chem, 1998 Oct 23, 273(43), 27786 - 93
An eukaryotic RuvB-like protein (RUVBL1) essential for growth; Qiu XB et al.; A human protein (RUVBL1), consisting of 456 amino acids (50 kDa) and highly homologous to RuvB, was identified by using the 14-kDa subunit of replication protein A (hsRPA3) as bait in a yeast two-hybrid system . RuvB is a bacterial protein involved in genetic recombination that bears structural similarity to subunits of the RF-C clamp loader family of proteins . Fluorescence in situ hybridization analysis demonstrated that the RUVBL1 gene is located at 3q21, a region with frequent rearrangements in different types of leukemia and solid tumors . RUVBL1 co-immunoprecipitated with at least three other unidentified cellular proteins and was detected in the RNA polymerase II holoenzyme complex purified over multiple chromatographic steps . In addition, two yeast homologs, scRUVBL1 and scRUVBL2 with 70 and 42% identity to RUVBL1, respectively, were revealed by screening the complete Saccharomyces cerevisiae genome sequence . Yeast with a null mutation in scRUVBL1 was nonviable . Thus RUVBL1 is an eukaryotic member of the RuvB/clamp loader family of structurally related proteins from bacteria and eukaryotes that is essential for viability of yeast.

Am J Gastroenterol, 1998 Oct, 93(10), 1996 - 8
Helicobacter colonization of the biliary tree: commensal, pathogen, or spurious finding?
Metz DC.
The authors hypothesized that Helicobacter species may be present in the bile and gallbladder wall of patients with chronic cholecystitis who live in a region with a high prevalence of gallbladder cancer . They attempted to identify such species by obtaining both bile and resected gallbladder tissue from 46 patients who underwent cholecystectomy . Tissue specimens were stained with hematoxylin and eosin as well as other stains used specifically for the identification of Helicobacter species, and culture was attempted using specialized media on samples from tissue and bile . Unfortunately, the authors were unable to culture any Helicobacter species, and the yield from histopathology was also poor with silver stains identifying curved bacteria suggestive, but not diagnostic, of Helicobacter species in only two cases . Molecular techniques were more successful . DNA was extracted from both tissue and bile and amplified by polymerase chain reaction (PCR) using a specific primer . The amplicons they identified were then compared with known Helicobacter proteins using a Southern blot approach . PCR amplification was relatively successful with 9 of 23 gallbladder samples and 13 of the 23 bile samples coming up positive for Helicobacter species using two specific primers . These specimens were also positive by Southern blot hybridization . The cloning and sequencing of the 16S ribosomal RNA amplicons in eight cases verified true Helicobacter origin with a phylogenetic analysis showing greater than 99.3% similarity . Five of the amplicons clustered with H . bilis, two with Flexispira rappini, and one with H . pullorum . The authors concluded that despite their being unable to identify organisms directly, the stringent PCR technique with amplicon sequencing confirmed that Helicobacter species could be identified within the bile and gallbladder tissue of patients with chronic cholecystitis in a region with high incidence of gallbladder cancer . They indicated that further studies are needed to ascertain whether similar species have a causative role in the development of gallbladder cancer.

Life Sci, 1998, 63(14), 1251 - 67
Some chemical properties and biological role of thiazolidine compounds; Terzuoli L et al.; In this study we have investigated some chemical properties and the biological role of thiazolidine compounds, obtained by condensation of aminothiols (L- or D-cysteine, cysteamine) with pyridoxal-5'-phosphate . These products have been tested in presence of rat liver extracts (supernatant and mitochondria); bacterial suspensions and enzymes (L- or D-aminoacid oxidase, xanthine oxidase) with interesting results which gives evidence to a biological role . Their formation in vivo may represent the regulation of intracellular levels of pyridoxal-5'-phosphate and aminothiols . Moreover, we have analysed the two diastereoisomers of the thiazolidine compounds derived from L-cysteine and D-cysteine: we have succeeded to distinguish by NMR analysis the cis and the trans forms, concluding that the interconversion of the free forms is extremely rapid at pH 7: thus, it may be relevant for the protein bound forms.

Probl Tuberk, 1998, (4), 13 - 4
{Dynamics of morbidity at health care institutions and penal labor facilities in the Udmurt Republic}; Russkikh OE et al.; Comparative analysis indicated that morbidity in the corrective labour institutions, Ministry Internal Affairs of the Udmurt Republic, is much higher than that in the therapeutical-and-prophylactic institutions of the republic . In the corrective labour institutions, patients who isolate bacteria and who have destructive processes are much more common . The clinical course of clinical tuberculosis is noted to be aggravated, there is an increase in the incidence of caseous pneumonia.

Exp Cell Res, 1998 Oct 10, 244(1), 340 - 8
Cytoskeletal association of an esterase in Dictyostelium discoideum; Chia CP et al.; A 70-kDa glycoprotein, gp70, was found enriched in the detergent-insoluble cytoskeletal fraction of axenically grown Dictyostelium discoideum cells . Its N-terminal amino acid sequence identified it as 'crystal protein' (L . Bomblies et al., 1990, J . Cell Biol . 110, 669-679) . This finding was corroborated when antibody to crystal protein cross-reacted with gp70 and its deglycosylated form . The postulated esterase activity of gp70/crystal protein was verified through comparative enzyme assays of extracts derived from cells that either overexpressed or lacked gp70 . Gp70 cosedimented with cytoskeletons on sucrose gradients, suggesting an interaction with the cytoskeleton . Coisolation of gp70 with detergent-extracted cells, observed by immunofluorescence microscopy, also implied a gp70-cytoskeletal association . These data supported the idea that the localization or secretion of gp70, or both, was cytoskeletally mediated . Although axenically grown cells contained high levels of gp70, the same cell lines had reduced levels of gp70 when grown in bacterial suspension or in nutrient media containing bacteria . Bacterially grown cells, compared to axenically grown cells, had lower fluid-phase uptake rates even when nutrient media was present, indicating that phagocytosis was a preferred mode of feeding . Thus, bacteria inhibited gp70 expression, which suggested a role for prestarvation factor, in regulating its synthesis .

Pathology, 1998 Aug, 30(3), 295 - 8
Chlamydia pneumoniae DNA is not detectable within sarcoidosis tissue; Mills GD et al.; Sarcoidosis is a granulomatous disease of unknown etiology . Recent studies have suggested the possibility of a bacterial origin with Chlamydia pneumoniae being one of the many bacteria considered . The aim of this study was to use the polymerase chain reaction (PCR) in an attempt to identify C . pneumoniae within fresh/frozen sarcoidosis tissue . Tissue from 20 sarcoidosis patients and 17 controls was evaluated . DNA was extracted from all tissue specimens and PCR amplified with primers specific for C . pneumoniae . All study tissues were negative for the presence of DNA sequences from C . pneumoniae . These findings could not be attributed to PCR inhibition or to lack of sensitivity of the PCR assay . The negative finding suggests either that there is no involvement between C . pneumoniae and sarcoidosis or that, having incited granulomata formation, it is no longer present in detectable amounts.

Pathol Biol (Paris), 1998 Feb, 46(2), 92 - 5
{Compact genomes}; Forterre P; The number of procaryotic genomes (both Archaea and Bacteria) completely sequenced is rapidly increasing since the publication in 1995 of the first ever finished one, Haemophilis influenzae . The small size and "simplicity" of these genomes make them ideal models for training in genomic before attacking more complex genomes, but they have also great intrinsic interest . Preliminary analyses of these compact genomes have detected many orphan genes, even in organisms previously extensively studied, as well as many families of duplicated genes . A major task now is to identify the function of these orphans by a combination of in silico, biochemical and genetic analyses (examples will be presented) . Several genomes of hyperthermophiles have been or will be completely sequenced soon . Many of their genes have commercial (stable proteins), as well as medical interest (crystallization of proteins with eucaryotic homologs involved in pathogenesis) . However, further work with these genomes will require the development of genetic tools for these hyperthermophiles . The complete understanding of genome evolution, structure and function will require the sequencing of many genomes at the different levels of the evolutionary scale . Sequencing of genomes from closely related organisms can be relevant to study genome plasticity, whilst sequencing of genome from different domains (Archaea, Bacteria, Eucarya) can help to reconstruct the Last Universal Common Ancestor (LUCA) . The latter is a difficult task and will require not only classical molecular phylogenetic studies (which can be sometimes greatly misleading) but also in depth comparative analyses of all central genetic mechanisms in the three domains to infer their respective evolution . The fundamental problem is to determine if the compact genome of procaryotes is indeed a primitive one (as suggested by the term procaryote itself) or if it has been compacted from a more complex one by evolutionary forces related to the procaryotic way of life . Finally, taking into account the extreme diversity of procaryotes and their metabolism, it should be kept in mind that beside a core of genes essential for cellular life, the myriad of procaryotic genomes contain a mine of non essential genes with potential commercial or medical application . The total number of these genes probably outnumber the total number of eucaryotic genes.

Med Clin North Am, 1998 Sep, 82(5), 1001 - 31, v
Infectious diseases; Ko WT et al.; Approximately 5% of the general population develops a skin infection each year, leading to a significant number of outpatient visits to the primary care physician . Bacteria, infestations, fungi, yeasts, and viruses are organisms that present with a myriad of cutaneous findings that pose a challenge to the investigating clinician . This article provides a contemporary review of these skin infections, with particular emphasis on clinical features, and a concise, updated review on therapies.

Trends Genet, 1998 Sep, 14(9), 368 - 74
Selfishness and death: raison d'être of restriction, recombination and mitochondria; Kobayashi I; Type II restriction-modification gene complexes, such as the EcoRI system, are not easily lost from their host cell . The descendants of cells that lose a restriction-modification gene complex are unable to modify a sufficient number of recognition sites in their chromosomes to protect them from lethal attack by the remaining molecules of restriction enzyme . This capacity to act as a selfish genetic element is likely to have contributed to the spread and maintenance of restriction-modification systems . Homologous recombination machineries of cells and viruses appear to be well adapted to cope with these elements . By extrapolation, the capacity of mitochondria to kill their host eukaryotic cell might have stabilized their initial symbiosis.

Toxicology, 1998 Aug 7, 129(1), 63 - 71
Biomarkers of immunotoxicity in fish and other non-mammalian sentinel species: predictive value for mammals?
Zelikoff JT.
Through the efforts of different laboratories, a battery of immunological assays is available to predict the immunotoxicity of xenobiotics . These assays, originally developed in rodents, have been adapted for use in a variety of animal species and are now used routinely in these models to assess the immunotoxicity of different chemical classes . For example, our laboratory has employed assays that measure antibody-forming cell response to T-dependent antigens, T- and B-cell lymphoproliferation, macrophage function, and host resistance against infectious bacteria to assess metal-induced immunotoxicity in laboratory-reared Japanese medaka (Oryzias latipes); immunologically-related assays measuring antioxidant activity have also been used in this capacity . Results of the aforementioned investigations have shown the usefulness of these endpoints to reliably demonstrate chemical-mediated immunotoxicity in teleost systems . Many of these same endpoints have also proved successful for predicting the immunotoxic effects of contaminated aquatic environments in feral fish populations . For example, smallmouth bass collected from a chlorinated hydrocarbon-contaminated site demonstrated significant changes in blood cell profiles and kidney phagocyte function compared to fish collected from a 'clean water' reference site . Some of these same immune parameters have also been used successfully to predict the immunotoxicity of polluted aquatic environments in feral populations of fish-eating birds and harbor seals . While interspecies extrapolation is difficult and should be approached with caution due to variables such as metabolism and pharmacokinetics, results from these studies demonstrate the usefulness of these immune assays to predict the immunomodulating effects of xenobiotics in fish and other wildlife species, as well as the applicability of fish to serve as additional/alternate animal models for mammalian species in immunotoxicological studies.

Presse Med, 1998 Jun 20, 27(22), 1084 - 8
{Severe pneumonia with a pneumococcal aspect during an ornithosis outbreak}; Goupil F et al.; OBJECTIVES: To describe the clinical, radiological and biological features of Chlamydia psittaci pneumonia . METHODS: A pneumonia outbreak occurred in a healthy middle-aged population working in a poultry slaughterhouse . Systematic serology (2 samples at 5 weeks intervals) provided the diagnosis of Chlamydia psittaci pneumonia in 6 patients . Patient files were analyzed retrospectively . RESULTS: The clinical presentations in this series of pneumonia were particularly homogeneous with a pneumococcal profile in all 6 cases: sudden onset, temperature above 39 degrees C, lobar alveolar involvement, hypoxemia, hyperleukocytosis and liver dysfunction . One case of hallucinatory delirium was observed . The patients were given spiramycin (9 million units per day for 3 weeks) and all recovered rapidly with no complications . CONCLUSION: The unusual virulence of the Chlamydia psittaci and very important inoculum were probably involved in this outbreak because of the severity of the pulmonary features and the short exposure of some patients to the bacteria . These cases suggest that the prevention of ornithosis in poultry slaughterhouses should be reinforced.

Mol Microbiol, 1998 Sep, 29(5), 1249 - 61
The pilH gene encodes an ABC transporter homologue required for type IV pilus biogenesis and social gliding motility in Myxococcus xanthus; Wu SS et al.; Type IV pilus genes have been shown to be required for social gliding motility in Myxococcus xanthus . We report the discovery of four additional pil genes: pilD, a homologue of type IV prepilin leader peptidases; and pilG, pilH and pilI, which have no known homologues in other type IV pilus systems . pilH encodes an ATP-binding cassette (ABC) transporter homologue, the first such homologue to be required for the biogenesis of any bacterial pilus type . pilG and pilI are co-transcribed with pilH and appear to be functionally related to pilH . Null mutants of pilG, pilH and pilI all lack social motility, are deficient in pilus production, have elevated sporulation efficiencies and display similar developmental abnormalities . In addition, all three mutations reduced the amount of PilA found in the supernatant after cells were sedimented from liquid culture . We suggest that the products of these three genes form a single ABC exporter complex, in which pilI is an integral membrane protein with membrane-spanning domains, and pilG is an accessory factor . The complex may participate in pilus assembly and/or the export of PilA pilin.

Mol Microbiol, 1998 Sep, 29(5), 1167 - 77
The identification of Mycobacterium marinum genes differentially expressed in macrophage phagosomes using promoter fusions to green fluorescent protein; Barker LP et al.; Mycobacterium marinum, like Mycobacterium tuberculosis, is a slow-growing pathogenic mycobacteria that is able to survive and replicate in macrophages . Using the promoter-capture vector pFPV27, we have constructed a library of 200-1000 bp fragments of M . marinum genomic DNA inserted upstream of a promoterless green fluorescent protein (GFP) gene . Only those plasmids that contain an active promoter will express GFP . Macrophages were infected with this fusion library, and phagosomes containing fluorescent bacteria were isolated . Promoter constructs that were more active intracellularly were isolated with a fluorescence-activated cell sorter, and inserts were partially sequenced . The promoter fusions expressed intracellularly exhibited homology to mycobacterial genes encoding, among others, membrane proteins and biosynthetic enzymes . Intracellular expression of GFP was 2-20 times that of the same clones grown in media . Several promoter constructs were transformed into Mycobacterium smegmatis, Mycobacterium bovis BCG and Mycobacterium tuberculosis . These constructs were positive for GFP expression in all mycobacterial strains tested . Sorting fluorescent bacteria in phagosomes circumvents the problem of isolating a single clone from macrophages, which may contain a mixed bacterial population . This method has enabled us to isolate 12 M . marinum clones that contain promoter constructs differentially expressed in the macrophage.

Mol Microbiol, 1998 Aug, 29(4), 955 - 61
Archaea and the cell cycle; Bernander R; Sequence similarity data suggest that archaeal chromosome replication is eukaryotic in character . Putative nucleoid-processing proteins display similarities to both eukaryotic and bacterial counterparts, whereas cell division may occur through a predominantly bacterial mechanism . Insights into the organization of the archaeal cell cycle are therefore of interest, not only for understanding archaeal biology, but also for investigating how components from the other two domains interact and work in concert within the same cell; in addition, archaea may have the potential to provide insights into eukaryotic initiation of chromosome replication.

Kidney Int, 1998 Oct, 54(4), 1367 - 71
Outbreak of sterile peritonitis among continuous cycling peritoneal dialysis patients; Mangram AJ et al.; BACKGROUND: Approximately 30,000 patients receive peritoneal dialysis in the United States . In August 1996, several dialysis centers from different states reported sterile peritonitis among CCPD patients using sterile peritoneal dialysis solution (PDS) from a single manufacturer . The manufacturer recalled 53 lots of PDS that had passed established industry guidelines and Food and Drug Administration (FDA) approved quality control tests {including endotoxin levels <0.5 endotoxin units (EU)/ml}, but had pre-sterilization bacterial colony counts >1 cfu/ml . METHODS: At one outpatient dialysis center, Hospital of the University of Pennsylvania (HUP), we conducted a retrospective cohort study of all CCPD patients treated during July 15 to August 30, 1996 . A case-patient was defined as any HUP patient with culture-negative peritoneal fluid with a white blood cell count >100/mm3, cloudy peritoneal fluid, and/or abdominal pain . PDS and tubing were cultured for bacteria and assayed for endotoxin . RESULTS: Overall, 14 of 28 patients had sterile peritonitis . The only risk factor identified was exposure to > or =1 lot of recalled PDS (14 of 22 vs . 0/6, P = 0.02); the more recalled lots received, the higher the attack rate (P = 0.0001) . Five of 47 PDS bags had detectable endotoxin; recalled lots were more likely to have measurable endotoxin than nonrecalled lots (5/19 vs . 0/17, P = 0.05) . When case-patients resumed CCPD using PDS from non-recalled lots, no further cases were reported . CONCLUSIONS: Our results suggest that this outbreak was caused by intrinsic PDS contamination with endotoxin . Pre-sterilization colony counts may be an important quality control indicator for CCPD fluids in conjunction with endotoxin levels.

Kidney Int, 1998 Oct, 54(4), 1041 - 51
Aquaporins in the kidney: emerging new aspects; Yamamoto T et al.; Since 1992 and the discovery of an MIP (major intrinsic protein of lens fiber cell) homologue protein that selectively permeates water, aquaporin (AQP), there has been an explosion of research in this field . Early research speculated that aquaporins played indispensible physiological roles in bacteria and plants, as well as in mammalian organs such as red blood cells, kidney, eye, brain and lung, where water transport rapidly takes place . Yet human subjects were identified who lacked AQP1 and yet had no apparent phenotypical changes clinically . To date 10 aquaporins have been discovered and a plethora of MIP members, and their prevalance in almost all organisms is a testament to their indispensible roles in the body, possibly as water and small neutral solute transporting channels . The recent localization of many different aquaporins in the same organ indicates that they may work cooperatively, which may partially explain the mystery of their physiological mechanism . Because the physiological roles of most aquaporins are currently only speculation, more extensive research is necessary to understand the exact function of each aquaporin.

Immunology, 1998 Jul, 94(3), 297 - 303
Treatment with recombinant granulocyte colony-stimulating factor (Filgrastin) stimulates neutrophils and tissue macrophages and induces an effective non-specific response against Mycobacterium avium in mice; Bermudez LE et al.; A role of neutrophils in the host response against Mycobacterium avium (MAC) has recently been suggested . To investigate this matter further, we determined the effect of granulocyte colony-stimulating factor (G-CSF) on the outcome of MAC infection in mice . C57BL/6bg+/bg- black mice were intravenously infected with 1 x 10(7) MAC and then divided into four experimental groups to receive G-CSF as follows: (i) 10 micrograms/kg/day; (ii) 50 micrograms/kg/day; (iii) 100 micrograms/kg/day; (iv) placebo control . Mice were killed at 2 and 4 weeks of treatment to determine the bacterial load of liver and spleen . Treatment with G-CSF at both 10 and 50 micrograms/kg/day doses significantly decreased the number of viable bacteria in liver and spleen after 2 weeks (approximately 70.5% and 69.0%, respectively), and after 4 weeks (approximately 53% and 52%, respectively, P < 0.05 compared with placebo control) . Treatment with 100 micrograms/kg/day did not result in decrease of bacterial colony-forming units in the liver and spleen after 4 weeks . Administration of G-CSF induced interleukin-10 (IL-10) and IL-12 production by splenocytes . To examine if the protective effect of G-CSF was accompanied by the activation of phagocytic cells, blood neutrophils and splenic macrophages were purified from mice receiving G-CSF and their ability to kill MAC was examined ex vivo . Neutrophils and macrophages from G-CSF-treated mice were able to inhibit the growth of or to kill MAC ex vivo, while phagocytic cells from untreated control mice had no anti-MAC effect . These results suggest that activation of neutrophils appears to induce an effective non-specific host defence against MAC, and further studies should aim for better understanding of the mechanisms of protection.

Biochemistry (Mosc), 1998 Aug, 63(8), 944 - 51
Interaction of human milk lactoferrin with ATP; Semenov DV et al.; Human lactoferrin exhibits many unique properties . It is known as one of the most important factors that provide nonspecific defense of cells against bacteria, viruses, and carcinogenesis, as well as an important component of a specific system responsible for the passive immunity of newborns . As a compound with extremely broad spectrum of functions many of which were not elucidated so far, lactoferrin is intensely studied . In this study we obtained electrophoretically and immunologically homogenous preparations of lactoferrin from human milk . Using various methods, we were the first to show that the fraction of lactoferrin, which displays an increased affinity for Sepharose Blue, forms complexes with ATP with a stoichiometry of 1 mole ATP per mole protein . It is shown that the ATP-binding site is located in the C-terminal domain of the lactoferrin molecule . The binding of ATP results in the dissociation of tetrameric forms of the protein and a change in the mode of interaction of lactoferrin with polysaccharides and other proteins . The data may be used in analysis of the possible reasons for multifunctional properties of lactoferrin and possible ways of regulation of its functions.

Biochim Biophys Acta, 1998 Oct 2, 1394(1), 3 - 15
Structure and expression of fatty acid desaturases; Los DA et al.; Fatty acid desaturases are enzymes that introduce double bonds into fatty acyl chains . They are present in all groups of organisms, i.e., bacteria, fungi, plants and animals, and play a key role in the maintenance of the proper structure and functioning of biological membranes . The desaturases are characterized by the presence of three conserved histidine tracks which are presumed to compose the Fe-binding active centers of the enzymes . Recent findings on the structure and expression of different types of fatty acid desaturase in cyanobacteria, plants and animals are reviewed in this article . Roles of individual desaturases in temperature acclimation and principles of regulation of the desaturase genes are discussed.

Parasitol Res, 1998 Sep, 84(9), 741 - 5
Multiple bacteroids in the bacteriome of the lantern bug Pyrops candelaria Linn . (Homoptera: Fulgoridae); Wang JB et al.; Bacteriome in the lantern bug Pyrops candelaria harbored a-, t-, and companion bacteroids . The a- and t-bacteroids were irregular bodies, whereas the companion bacteroids were rod-shaped and easily distinguished from the others . The a- and t-bacteroids were enveloped by three membranes and the companion bacteroids, by two membranes . The cytoplasm of the a-bacteroid contained electron-dense bodies.

Res Microbiol, 1997 Nov, 148(8), 661 - 71
Endo-N-acetyl-beta-D-glucosaminidases and their potential substrates: structure/function relationships; Karamanos Y; Endo-N-acetyl-beta-D-glucosaminidases (ENGases) have been defined as the enzymes that hydrolyse the glycosidic bond between an N-acetyl-beta-D-glucosamine residue and the adjacent (partner) monosaccharide within an oligosaccharide chain . Three types of enzymes have been distinguished according to this definition: ENGases acting on murein (type I), those acting on chitin (type II) and, finally, those acting on N-glycans (type III) . Considering that N-acetylmuramic acid is a derivative of N-acetylglucosamine (3-O-substituted by a lactyl group), only ENGases acting between two N-acetylglucosamine residues are actually known despite the fact that other possibilities of partner monosaccharides for N-acetyl-beta-D-glucosamine are reported . Similarities in the amino acid sequences were found to occur only between chitin-ENGases and N-glycan-ENGases, but the substrate specificities of these two types of enzymes are different . However, it is possible that certain enzymes are able to cleave more than one type of substrate, and this could in particular explain why the N-glycan-ENGases are largely produced by bacteria in which no potential substrate for this type of enzymes was identified . Further study in this area is expected.

Res Microbiol, 1997 May, 148(4), 315 - 26
Strategy for the detection of Helicobacter species by amplification of 16S rRNA genes and identification of H . felis in a human gastric biopsy; Germani Y et al.; The aim of the present work was to develop polymerase chain reactions (PCRs) based on the conserved nucleotide sequence of the 16S rRNA gene for detection of bacteria of the Helicobacter genus in human antral biopsy samples . The assay for Helicobacter spp was developed by amplifying a 399-bp 16S rRNA gene sequence specific to the genus Helicobacter . The identity of the amplicon was confirmed by hybridization with an internal probe and by restriction by endonuclease VspI showing two expected fragments of 295 and 104 base pairs . A total of 65 dyspeptic patients from France and New Caledonia were screened for Helicobacter spp infection through the use of the following diagnostic assays on biopsy specimens collected through endoscopy: direct detection of bacteria in histological sections by Giemsa and Warthin Starry staining, urease test and bacterial isolation, PCR for Helicobacter pylori ureC/glmM gene, and PCR targeted to 16S rRNA genes . The 16S rRNA gene PCR assay was able to detect down to 680 bacterial cells, as assessed by agarose gel electrophoresis, and down to 4 bacterial cells by hybridization of amplicon with the internal probe . The 16S rRNA PCR test was 100% specific and sensitive; results obtained with this test were in agreement with the visualization of bacteria by histology . Urease test and culture were 86.4% and 22.7% sensitive, and 96.5 and 100% specific, respectively . The H . pylori ureC/glmM gene-based PCR was 100% specific and only 95.4% sensitive, since one biopsy from a Melanesian patient contained a Helicobacter strain other than H . pylori . For this Melanesian patient, a branch-specific PCR targeting the epsilon branch of Proteobacteria was used to amplify a 967-bp amplicon . This amplicon was sequenced and matched with the H . felis sequence . This was confirmed using an H . felis-specific urease PCR test.

Biochim Biophys Acta, 1998 Aug 20, 1399(2-3), 161 - 72
A mutation in repB, the dictyostelium homolog of the human xeroderma pigmentosum B gene, has increased sensitivity to UV-light but normal morphogenesis; Lee SK et al.; Nucleotide excision repair (NER) is an important cellular defense mechanism which protects the integrity of the genome by removing DNA damage caused by UV-light or chemical agents . In humans, defects in the NER pathway result in the disease xeroderma pigmentosum (XP) which is characterized by increased UV-sensitivity, with increased propensity for skin cancer, and an array of developmental abnormalities . Some XP patients exhibit, in addition, symptoms of Cockayne's syndrome (CS) and trichothiodystrophy (TTD), which are characterized by increased UV-sensitivity, without increased cancer incidence, and an array of developmental abnormalities . Some NER genes, including the DNA helicases XPB and XPD, have been shown to function in transcription as well as repair, by virtue of being an integral part of the transcription initiation factor TFIIH . This dual function may account for the above-mentioned wide pleiotropy of phenotypes associated with defects in NER genes, and may explain why some XP patients exhibit developmental abnormalities in addition to XP symptoms . To date, only five XPB patients with three different mutations in the XPB gene have been reported . One of these mutations is a C to A transversion at the splice site at the beginning of the last exon, which resulted in a frameshift throughout the last exon . This patient shows combined clinical symptoms of XP and CS . The recent cloning of the repB gene, the Dictyostelium discoideum homolog of XPB, allowed us to generate a similar C-terminal mutation in the Dictyostelium, in order to test whether the defect in this NER gene has an effect on growth or development . To this end, we have constructed a C-terminal deletion repB mutant in Dictyostelium . To avoid the possibility that a null mutant would be lethal, we used direct homologous recombination to create a 46 amino acid C-terminal deletion mutant . Indeed, we were unable to obtain mutants with a longer 95 amino acid deletion . The repB delta C46 mutants showed an increased sensitivity to UV-light, but a normal pattern of UV-induced expression of repair genes, and no immediately obvious defect in either growth rate or development . The results suggest that the associated developmental defects in the human XPB patients may be due to mutations in another gene.

J Bacteriol, 1998 Oct, 180(20), 5351 - 6
The NADP-dependent methylene tetrahydromethanopterin dehydrogenase in Methylobacterium extorquens AM1; Vorholt JA et al.; An NADP-dependent methylene tetrahydromethanopterin (H4MPT) dehydrogenase has recently been proposed to be involved in formaldehyde oxidation to CO2 in Methylobacterium extorquens AM1 . We report here on the purification of this novel enzyme to apparent homogeneity . Via the N-terminal amino acid sequence, it was identified to be the mtdA gene product . The purified enzyme catalyzed the dehydrogenation of methylene H4MPT with NADP+ rather than with NAD+, with a specific activity of approximately 400 U/mg of protein . It also catalyzed the dehydrogenation of methylene tetrahydrofolate (methylene H4F) with NADP+ . With methylene H4F as the substrate, however, the specific activity (26 U/mg) and the catalytic efficiency (Vmax/Km) were approximately 20-fold lower than with methylene H4MPT . Whereas the dehydrogenation of methylene H4MPT (E0 = -390 mV) with NADP+ (E0 = -320 mV) proceeded essentially irreversibly, the dehydrogenation of methylene H4F (E0 = -300 mV) was fully reversible . Comparison of the primary structure of the NADP-dependent dehydrogenase from M . extorquens AM1 with those of methylene H4F dehydrogenases from other bacteria and eucarya and with those of methylene H4MPT dehydrogenases from methanogenic archaea revealed only marginally significant similarity (<15%).

Viral Immunol, 1998, 11(2), 55 - 63
DNA/genetic vaccination (minireview); Kucerova L; An important new approach to vaccination is plasmid DNA injection in vivo that can elicit an immune response against protein(s) encoded . Antigen that is expressed from the in vivo transfected cells induces both humoral and cellular immune response . DNA immunization is generally applicable for a wide range of proteins . It can provide an organism with immunity against viruses, bacteria, parasites, and tumors . DNA vaccines can overcome the disadvantages of vaccines presently used as well as provide various new vaccines that are currently not available . This minireview provides an overview of evaluated DNA vaccine candidates against infectious agents and certain cancers.

Cell Mol Biol (Noisy-le-grand), 1998 Jul, 44(5), 689 - 700
Cell biological applications of scanning near-field optical microscopy (SNOM); Subramaniam V et al.; Scanning near-field optical microscopy (SNOM) yields high-resolution topographic and optical images and is an important technique for visualizing biological systems . We summarize the literature on SNOM of biological systems and present some of our recent applications in cellular biology . These include studies of: i) the binding of fluorescently conjugated lectins to cell surface glycoproteins on 3T3 Balb/c cells, ii) molecular interactions by fluorescence resonance energy transfer using photobleaching techniques, and iii) green fluorescent protein (GFP) expressed in bacteria.

Clin Exp Immunol, 1998 Oct, 114(1), 13 - 8
Macrophage function in alloxan diabetic mice: expression of adhesion molecules, generation of monokines and oxygen and NO radicals; Ptak W et al.; The increased incidence of bacterial and mycotic infections in poorly controlled diabetic patients or animals is frequently attributed to impaired activities of professional phagocytes (granulocytes, macrophages) in hypoinsulinaemic milieu . We measured production of monokines (IL-6 and tumour necrosis factor-alpha (TNF-alpha)), active NO and reactive oxygen intermediates (ROIs), as well as expression of several cell surface adhesion molecules (Mac-1, -2 and -3, intercellular adhesion molecule-1 (ICAM-1) and Fc gammaRII), by thioglycollate medium-induced peritoneal macrophages of normoglycaemic and alloxan diabetic CBA/J mice (blood glucose level in the range 300 or 500 mg/dl) . Macrophages of animals with moderate diabetes (300 mg/dl) produced significantly more IL-6 and TNF-alpha and ROIs than cells of control mice and showed an increased expression of all cell surface molecules, except Mac-3 . NO/NO2 production was not affected . Administration of insulin restored enhanced values to normal levels, except for the production of ROIs which remained unusually high . We conclude that two separate mechanisms influence macrophage physiology in diabetes--lack of saturation of insulin receptors on macrophages and an indirect effect due to formation of advanced glycosylation endproducts (AGE) on their surfaces . The latter is possibly responsible for increased generation of ROIs, since it cannot be down-regulated by prolonged insulin treatment . How the increased activity of macrophages of moderately diabetic mice (enhanced production of proinflammatory monokines and oxygen radicals as well as expression of molecules) is related to their ability to kill bacteria is now under investigation.

Farmaco, 1998 Jun 30, 53(6), 409 - 14
Glycosidopyrroles . Part 3 . Effect of the benzocondensation on acyclic derivatives: 1-(2-hydroxyethoxy) methylindoles as potential antiviral agents; Almerico AM et al.; The new of 1-(2-hydroxyethoxy)methylindole derivatives 3a-i were prepared in good yields . None of them showed any significant anti-HIV activity and therefore the benzocondensation between the 2 and 3 positions of the pyrrole ring definitely reduced the weak activity found in the analogues 1a-c.

Scand J Urol Nephrol, 1998 Jul, 32(4), 284 - 9
Bacteriuria in a population sample of women: 24-year follow-up study . Results from the prospective population-based study of women in Gothenburg, Sweden; Bengtsson C et al.; The aims of the study were to estimate the prevalence of bacteriuria in a female urban population, to follow up the same population over the years, and to relate bacteriuria to long-term prognosis with respect to mortality and kidney disease . The study was based on a randomly selected population sample comprising 1462 women aged 38-60 years at entrance to the study in 1968-69 with an initial participation rate of 90.1% . Bacteriuria was observed in 3-5%, increasing with age, and most often asymptomatic . Bacteriuria on one occasion meant increased risk of having bacteriuria 6 and 12 years later . The percentages of different types of bacteria and the resistance pattern were similar initially and at follow-up studies after 6 and 12 years . There were no differences in mortality or incidence of severe kidney disease during a 24-year follow-up between those with and those without bacteriuria in the baseline study.

Blood, 1998 Oct 15, 92(8), 2940 - 50
Molecular identification and functional characterization of a novel protein that mediates the attachment of erythroblasts to macrophages; Hanspal M et al.; We have previously identified a novel protein that mediates the attachment of erythroblasts to macrophages in vitro . This attachment promotes terminal maturation and enucleation of erythroblasts (Hanspal and Hanspal, Blood 84:3494, 1994) . This protein is referred to here as Emp for erythroblast macrophage protein . Two immunologically related isoforms of Emp with apparent molecular weights of 33 kD and 36 kD were detected in macrophage membranes . The complete amino acid sequence of the larger isoform of Emp was deduced from the nucleotide sequence of a full-length 2.0-kb cDNA that was isolated from a human macrophage cDNA library using affinity-purified anti-Emp antibodies . Of the 2,005 bp, 1,185 bp encode for 395 amino acids representing 43 kD (the sodium dodecyl sulfate-polyacrylamide gel electrophoresis {SDS-PAGE} molecular mass is 36 kD) . Northern blot analysis of human macrophage poly(A) RNA detected a message for Emp of 2.1 kb . The deduced amino acid sequence contains a putative transmembrane domain near the N-terminus . To investigate the structure/function relationships of Emp, recombinant fusion proteins of full-length and truncated Emp were produced in bacteria, COS-7, and HeLa cells . Cell binding assays showed that the N-terminus is exposed on the cell surface . The recombinant Emp functions as a cell attachment molecule when expressed in heterologous cells . Furthermore, we showed that the demise of erythroblasts in the absence of Emp-mediated erythroblast-macrophage association is accompanied by apoptosis . We postulate that Emp-mediated contact between erythroblasts and macrophages promotes terminal maturation of erythroid cells by suppressing apoptosis .

Arch Dermatol Res, 1998 Aug, 290(8), 441 - 5
The genetic basis of "Scarsdale Gourmet Diet" variegate porphyria: a missense mutation in the protoporphyrinogen oxidase gene; Frank J et al.; The porphyrias are disorders of porphyrin or porphyrin-precursor metabolism that result from inherited or acquired aberrations in the control of the porphyrin-heme biosynthetic pathway . Variegate porphyria (VP), one of the acute hepatic porphyrias, is characterized by a partial reduction in the activity of protoporphyrinogen oxidase (PPO), and recently, mutations in the PPO gene on chromosome 1q22-23 have been described . Our purpose was to identify the underlying genetic lesion in a severely affected patient with VP and to detect the silent mutation carriers in her family . The disease in this patient was precipitated by carbohydrate restriction as outlined in the "Scarsdale Gourmet Diet" . Our mutation detection and confirmation strategy included PCR, automated sequencing, and restriction enzyme digestion . We identified a missense mutation in the patient and five family members . The mutation consisted of a previously unreported C-to-T transition in exon 5 of the PPO gene, resulting in the substitution of arginine by cysteine, designated R152C . This arginine residue is evolutionarily highly conserved in humans, mice, bacteria, yeast, and plants, indicating the importance of this residue in PPO . Our study established that a missense mutation in the PPO gene was the underlying mutation in this patient with VP and explained the occurrence of the phenotype in this family.

Acta Crystallogr D Biol Crystallogr, 1998 Jul 1, 54 ( Pt 4), 650 - 3
Crystallization and preliminary X-ray crystallographic studies of the native and chemically modified anion-selective porin from Comamonas acidovorans; Zeth K et al.; Omp32, the strongly anion-selective porin from Comamonas acidovorans, has been crystallized . Two crystal forms were observed, both of which belong to space group R3, but exhibit different cell dimensions a = b = 106.7, c = 140.6 A (crystal form I) and a = b = 87.1, c = 135.3 A (crystal form II) with one trimer per asymmetric unit . The crystals diffract to 2.2 and 2.3 A resolution, respectively . Omp32 was chemically modified by introducing negative charges through succinylation . The number and positions of the individual modifications were determined using mass spectrometry and X-ray crystallography . Chemically modified porins yielded crystals of a third form, also of space group R3 but with cell constants of a = b = 109.3 and c = 263.2 A (crystal form III), showing a virtually doubled c axis . Crystals of form III diffract to 3.5 A resolution.

Anal Biochem, 1978 Nov, 91(1), 101 - 14
The resolution of membrane proteins based upon size, charge, and hydrophobicity; Fernandes PB et al.; Currently available systems for resolving membrane proteins are based only on size and charge differences . Recently, it has been shown that Triton-urea-acetic acid gels which separate proteins on the basis of charge, size and hydrophobicity are capable of resolving proteins differing only by the substitution of a single neutral amino acid . We have applied this new method to the resolution of bacterial envelope proteins . Conditions for optimal resolution of different bacterial envelope proteins were determined by electrophoresis through transverse urea and Triton X-100 gradient gels . We have also correlated the components resolved in this system with those resolved by classical sodium dodecyl sulfate-gel electrophoresis by using two-dimensional slab gels combining the two systems . Furthermore, envelope protein fractions from different species and strains of bacteria were compared to identify specific proteins . This system appears to be a promising method for investigating envelope proteins which are due to missense mutations.

Biochem J, 1998 Oct 15, 335 ( Pt 2), 449 - 55
Identification of glu-277 as the catalytic nucleophile of Thermoanaerobacterium saccharolyticum beta-xylosidase using electrospray MS; Vocadlo DJ et al.; Thermoanaerobacterium saccharolyticum beta-xylosidase is a member of family 39 of the glycosyl hydrolases . This grouping comprises both retaining beta-d-xylosidases and alpha-l-iduronidases . T . saccharolyticum beta-xylosidase catalyses the hydrolysis of short xylo-oligosaccharides into free xylose via a covalent xylosyl-enzyme intermediate . Incubation of T . saccharolyticum beta-xylosidase with 2,4-dinitrophenyl 2-deoxy-2-fluoro-beta-d-xyloside resulted in time-dependent inactivation of the enzyme (inactivation rate constant ki=0.089 min-1, dissociation constant for the inactivator Ki=65 microM) through the accumulation of a covalent 2-deoxy-2-fluoro-alpha-d-xylosyl-enzyme, as observed by electrospray MS . Removal of excess inactivator and regeneration of the free enzyme through transglycosylation with either xylobiose or thiobenzyl xyloside demonstrated that the covalent intermediate was kinetically competent . Peptic digestion of the 2-deoxy-2-fluoro-alpha-d-xylosyl-enzyme intermediate and subsequent analysis by electrospray ionization triple-quadrupole MS in the neutral-loss mode indicated the presence of a 2-deoxy-2-fluoro-alpha-d-xylosyl peptide . Sequence determination of the labelled peptide by tandem MS in the daughter-ion scan mode permitted the identification of Glu-277 (bold and underlined) as the catalytic nucleophile within the sequence IILNSHFPNLPFHITEY.

J Mol Biol, 1998, 283(1), 29 - 41
Multiple oligomerisation domains in the IS911 transposase: a leucine zipper motif is essential for activity; Haren L et al.; Structure-function relationships involved in oligomerisation of the transposase OrfAB of the bacterial insertion sequence IS911 have been investigated . Site-directed mutagenesis and sequential deletion coupled with immunoprecipitation have led to the definition of three regions of the protein capable of promoting multimerisation . These include a region predicted to assume a coiled-coil conformation, which is shown to be essential for activity, promoting correct multimerisation of the N-terminal domain of OrfAB and sequence-specific binding to the IS911 terminal inverted repeats mediated by this domain . This region presents the structural and functional characteristics of the leucine zipper motif described in eukaryotic proteins . The two other regions are located further towards the C-terminal end of the protein, adjacent to the leucine zipper and in the region that carries the conserved catalytic DD(35)E motif .

Immunol Lett, 1998 Sep, 63(2), 107 - 12
Different effect of 1,25-dihydroxyvitamin D3 on replication of Mycobacterium avium in monocyte-derived macrophages from human immunodeficiency virus-infected subjects and healthy controls; Haug CJ et al.; Mycobacterium avium complex (MAC) is the most common cause of disseminated bacterial infection in patients with acquired immune deficiency syndrome (AIDS) and macrophage dysfunction is important both in the pathogenesis of AIDS- and MAC-infection . 1,25-Dihydroxyvitamin D3 (1,25D), the active metabolite of vitamin D, has a number of effects on cell types of the immune system including monocytes/macrophages . The present study was designed to investigate whether 1,25D supplementation in vitro could modulate MAC replication in macrophages from HIV-infected patients . It was therefore of particular interest to examine whether the effect of 1,25D differs between cells from HIV-infected patients and healthy control subjects . After 3 and 7 days of infection, 1,25D supplementation increased numbers of bacteria in cells from control subjects . In contrast, there was no change or even a decrease in numbers of bacteria in cells from HIV-infected patients . These findings suggest that HIV infection may significantly modulate the macrophage response to 1,25D stimulation, and that 1,25D may have inhibitory effects on MAC replication in macrophages from HIV-infected patients.

Biochemistry, 1998 Oct 6, 37(40), 14038 - 47
Activation of methylesterase CheB: evidence of a dual role for the regulatory domain; Anand GS et al.; The response regulator CheB functions within the bacterial chemotaxis system together with the methyltransferase CheR to control the level of chemoreceptor methylation, influencing the signaling activities of the receptors . CheB catalyzes demethylation of specific methylglutamate residues introduced into the chemoreceptors by CheR . CheB has a two-domain architecture consisting of an N-terminal regulatory domain joined by a linker to a C-terminal effector domain . In the unphosphorylated state of the response regulator, the regulatory domain inhibits the methylesterase activity of the effector domain . Upon phosphorylation of a specific aspartate residue within the regulatory domain, the C-terminal methylesterase activity is stimulated, resulting in the subsequent demethylation of the chemoreceptors . We have investigated the mechanism of regulation of CheB activity by the N-terminal regulatory domain . First, we have found that phosphorylation of the N-terminal domain not only relieves inhibition of the C-terminal methylesterase activity but also provides an enhancement of this activity above that seen for the C-terminal effector domain alone . Second, we have identified mutations in CheB that show an enhancement of methylesterase activity in the absence of phosphorylation . Most of these single-site mutations are localized in the linker region joining the regulatory and effector domains . On the basis of these observations, we propose a model for activation of CheB in which phosphorylation of the regulatory domain results in a reorganization of the domain interface, allowing exposure of the active site to the receptor substrate and simultaneously stimulating methylesterase activity.

J Immunol, 1998 Oct 1, 161(7), 3685 - 93
Soluble ICAM-1 activates lung macrophages and enhances lung injury; Schmal H et al.; Because of the important role of rat ICAM-1 in the development of lung inflammatory injury, soluble recombinant rat ICAM-1 (sICAM-1) was expressed in bacteria, and its biologic activities were evaluated . Purified sICAM-1 did bind to rat alveolar macrophages in a dose-dependent manner and induced production of TNF-alpha and the CXC chemokine, macrophage inflammatory protein-2 (MIP-2) . Alveolar macrophages exhibited cytokine responses to both sICAM-1 and immobilized sICAM-1, while rat PBMCs failed to demonstrate similar responses . Exposure of alveolar macrophages to sICAM-1 resulted in NFkappaB activation (which was blocked by the presence of the aldehyde peptide inhibitor of 28S proteosome and by genistein, a tyrosine kinase inhibitor) . As expected, cross-linking of CD18 on macrophages with Ab resulted in generation of TNF-alpha and MIP-2 . This response was also inhibited in the presence of the proteosome inhibitor and by genistein . Alveolar macrophages showed adherence to immobilized sICAM-1 in a CD18-dependent manner . Finally, airway instillation of sICAM-1 intensified lung injury produced by intrapulmonary deposition of IgG immune complexes in a manner associated with enhanced lung production of TNF-alpha and MIP-2 and increased neutrophil recruitment . Therefore, through engagement of beta2 integrins, sICAM-1 enhances alveolar macrophage production of MIP-2 and TNF-alpha, the result of which is intensified lung injury after intrapulmonary disposition of immune complexes.

J Immunol, 1998 Oct 1, 161(7), 3582 - 8
Down-regulation of CD1 on antigen-presenting cells by infection with Mycobacterium tuberculosis; Stenger S et al.; Intracellular pathogens have developed efficient evasion strategies to survive the defenses of the host immune system . In this study, we describe a new escape mechanism utilized by Mycobacterium tuberculosis that involves the down-regulation of the Ag-presenting molecule CD1 from the cell surface of CD1+ APCs . The loss of CD1 from the cell surface is associated with a complete inhibition of the ability of the infected cells to present Ag to CD1-restricted T cells . The down-regulation of Ag-presenting molecules on CD1+ APC by infection with M . tuberculosis is unique for CD1, since the expression of the classical Ag-presenting molecules MHC class I and MHC class II is not influenced . Our data show that efficient down-regulation of CD1 requires infection of the cells with live mycobacteria, since heat killing of the bacteria completely abrogates the effect . The observed down-regulation is not due to the secretion of cytokines or other host- or pathogen-derived factors . Investigation of upstream events responsible for the down-regulation of CD1 revealed that infection with live M . tuberculosis decreased the steady state CD1-mRNA levels . This study introduces a novel evasion mechanism of M . tuberculosis that could contribute to persistence of intracellular infection by avoiding immune recognition.

J Immunol, 1998 Oct 1, 161(7), 3315 - 24
Neonatal murine B lymphocytes respond to polysaccharide antigens in the presence of IL-1 and IL-6; Chelvarajan RL et al.; Unlike adults, neonates are unable to respond to polysaccharide Ags, making them especially vulnerable to pathogenic encapsulated bacteria . Since the Ab response to polysaccharides in adult mice requires certain cytokines, it was hypothesized that neonatal murine B cells may be competent to respond to such Ags, but may fail to do so due to a deficiency of cytokines . Neonatal splenocyte cultures, which were otherwise unresponsive to trinitrophenyl (TNP)-Ficoll, a haptenated polysaccharide Ag, mounted an adult-like Ab response when supplemented with IL-1 . However, IL-1 failed to induce such a response to TNP-Ficoll when purified B cells were used instead . Although IL-6 alone did not induce a response in whole spleen cells or purified B cells from neonates, it synergized with IL-1 in inducing purified neonatal B cells to respond to TNP-Ficoll . The avidity of the cytokine-induced neonatal anti-TNP Abs was comparable to that of Abs made by adult splenocyte cultures . One effect of IL-1 may be at the level of clonal expansion, since it induced neonatal B cells to proliferate in response to anti-IgM, which was further enhanced by IL-6 . The spontaneous secretion of IL-1 by neonatal splenocytes was below the detection limit, while adult splenocytes secreted 30.8 +/- 5.2 U/ml, which is of the same order of magnitude as what was required to stimulate neonatal B cells to respond to TNP-Ficoll . Thus, the neonatal unresponsiveness to polysaccharide Ags could be due to the inability of a non-B cell population resident in the neonatal spleen to secrete sufficient quantities of IL-1.

J Immunol, 1998 Oct 1, 161(7), 3256 - 61
A role for NK cells as regulators of CD4+ T cells in a transfer model of colitis; Fort MM et al.; Previous studies have shown that the chronic inflammation observed in the colon of IL-10-deficient (IL-10(-/-)) mice is mediated by CD4+ Th1 T cells and is dependent on the presence of IFN-gamma for its initial development . As CD4+ T cells from IL-10(-/-) mice will cause colitis when transferred into recombinase-activating gene (Rag)-deficient recipients, we considered the possibility that the recipients' NK cells could be an important source of IFN-gamma for the development of colitis . Therefore, the ability of IL-10(-/-) CD4+ T cells to cause colitis in Rag-deficient recipients that had been depleted of NK cells was tested . Contrary to our expectations, NK cell-depleted recipients of IL-10(-/-) CD4+ T cells developed accelerated disease compared with nondepleted recipients . Furthermore, CD4+ T cells from normal mice (IL-10(+/+)) also caused colitis in NK cell-depleted recipient mice, but not in nondepleted recipients . NK cells inhibited effector CD4+CD45RBhigh T cells, and subsequent experiments showed that this effect was dependent on perforin . Thus NK cells can play an important role in down-regulating Thl-mediated colitis by controlling the responses of effector T cells to gut bacteria.

Annu Rev Biochem, 1998, 67, 153 - 80
Ribonuclease P: unity and diversity in a tRNA processing ribozyme; Frank DN et al.; Ribonuclease P (RNase P) is the endoribonuclease that generates the mature 5'-ends of tRNA by removal of the 5'-leader elements of precursor-tRNAs . This enzyme has been characterized from representatives of all three domains of life (Archaea, Bacteria, and Eucarya) (1) as well as from mitochondria and chloroplasts . The cellular and mitochondrial RNase Ps are ribonucleoproteins, whereas the most extensively studied chloroplast RNase P (from spinach) is composed solely of protein . Remarkably, the RNA subunit of bacterial RNase P is catalytically active in vitro in the absence of the protein subunit (2) . Although RNA-only activity has not been demonstrated for the archael, eucaryal, or mitochondrial RNAs, comparative sequence analysis has established that these RNAs are homologous (of common ancestry) to bacterial RNA . RNase P holoenzymes vary greatly in organizational complexity across the phylogenetic domains, primarily because of differences in the RNase P protein subunits: Mitochondrial, archaeal, and eucaryal holoenzymes contain larger, and perhaps more numerous, protein subunits than do the bacterial holoenzymes . However, that the nonbacterial RNase P RNAs retain significant structural similarity to their catalytically active bacterial counterparts indicates that the RNA remains the catalytic center of the enzyme.

Appl Environ Microbiol, 1998 Oct, 64(10), 3998 - 4006
Isolation and identification of Helicobacter spp . from canine and feline gastric mucosa; Jalava K et al.; It is known that virtually all healthy adult dogs and cats harbor spiral helicobacters in their gastric mucosa . Three species, Helicobacter felis, Helicobacter bizzozeronii, and Helicobacter salomonis have been isolated in vitro from the gastric mucosa of these animals . The aims of this study were to evaluate the efficacy of an isolation method for canine and feline gastric helicobacters that has been developed at the University of Helsinki; to estimate the prevalence and distribution of these taxa in the samples examined; and to assess the efficacy and validity of an extensive set of standardized conventional phenotypic tests, whole-cell protein profiling, and ultrastructural analysis in identifying the different species isolated from canine and feline gastric mucosa . We cultured 95 and 22 gastric mucosal biopsies from dogs and cats, respectively . Twenty-one H . bizzozeronii strains, 8 H . felis strains, 8 H . salomonis strains, 3 mixed cultures, 2 "Flexispira rappini"-like organisms, and 3 as yet uncharacterized strains were isolated from the dogs, and 3 H . felis strains were isolated from the cats . The methods used here yielded Helicobacter isolation rates of 51% from dogs and 13.6% from cats, which exceed those reported previously . The main difficulties were primary isolation, mixed cultures, and identification to the species level . In the species identification, a detailed morphological examination was found to yield important phenotypic characteristics . A large panel of biochemical and tolerance tests did not clearly differentiate the closely related species H . bizzozeronii, H . felis, and H . salomonis . Highly standardized whole-cell protein profiling was shown to be an excellent method for species identification . Improvements in culture conditions for these bacteria are still needed, especially for cats . A genetic identification method not requiring culture is needed for future studies of these very fastidious helicobacters, as the clinical significance and ecology of these species within the gastric mucosa of the domestic carnivores remain largely unknown.

Appl Environ Microbiol, 1998 Oct, 64(10), 3707 - 12
Effect of butyrolactone I on the producing fungus, Aspergillus terreus; Schimmel TG et al.; Butyrolactone I {alpha-oxo-beta-(p-hydroxyphenyl)-gamma-(p-hydroxy-m-3, 3-dimethylallyl-benzyl)-gamma-methoxycarbonyl-gamma-butyrolactone} is produced as a secondary metabolite by Aspergillus terreus . Because small butyrolactone-containing molecules act as self-regulating factors in some bacteria, the effects of butyrolactone I on the producing organism were studied; specifically, changes in morphology, sporulation, and secondary metabolism were studied . Threefold or greater increases in hyphal branching (with concomitant decreases in the average hyphal growth unit), submerged sporulation, and secondary metabolism were observed when butyrolactone I was added to cultures of A . terreus . Among the secondary metabolites whose production was increased by this treatment was the therapeutically important compound lovastatin . These findings indicate that butyrolactone I induces morphological and sporulation changes in A . terreus and enhances secondary metabolite production in a manner similar to that previously reported for filamentous bacteria.

Arch Oral Biol, 1998 Aug, 43(8), 629 - 32
Discoloration of dental carious lesions (a review); Kleter GA; The discoloration of dental carious lesions is a marked feature which has received relatively little attention from dental researchers . In this short review, possible causes are considered: the formation of Maillard pigments, melanins, and lipofuscins, and the uptake of food dyes, metals, and bacterial pigments . It is concluded that the Maillard reaction between proteins and small aldehydes produced by bacteria probably accounts for the discoloration.

Am J Obstet Gynecol, 1998 Sep, 179(3 Pt 1), 650 - 6
Evaluating rapid diagnostic tests of intra-amniotic infection: Gram stain, amniotic fluid glucose level, and amniotic fluid to serum glucose level ratio; Hussey MJ et al.; OBJECTIVE: The aim of the study was to compare the diagnostic utility of the Gram stain, the amniotic fluid glucose level, and the ratio of amniotic fluid glucose level to serum glucose level in detecting intra-amniotic infection . STUDY DESIGN: We conducted a prospective study of 127 patients with preterm labor and 26 patients with preterm premature rupture of the membranes (153 total) . All patients underwent amniocentesis to diagnose intra-amniotic infection . The diagnostic criterion for intra-amniotic infection was a positive amniotic fluid culture result . RESULTS: The Gram stain is 80% sensitive and 91% specific when a positive is considered the presence of white blood cells or bacteria . Amniotic fluid glucose level and the ratio of amniotic fluid glucose level to serum glucose level are significantly lower when amniotic fluid culture results are positive, but as diagnostic tests they are inferior to the Gram stain . Logistic regression models that combine predictors yield superior accuracy with respect to individual tests . The most accurate combination was amniotic fluid glucose level and Gram stain with white blood cells or bacteria . Although the number of patients with preterm premature rupture of the membranes was small in this study (n = 26), analysis of our data suggests that the diagnostic performance levels of these tests were similar when used in patients with preterm labor and intact membranes and in patients with premature rupture of the membranes . CONCLUSIONS: The amniotic fluid glucose level and the ratio of amniotic fluid to serum glucose level have equivalent diagnostic utility and are inferior to the Gram stain . The combination of Gram stain with amniotic fluid glucose level is superior to any individual test.

Hum Immunol, 1998 Oct, 59(10), 635 - 43
T cell responses to 53-kDa outer membrane protein of Porphyromonas gingivalis in humans with early-onset periodontitis; Ohyama H et al.; Patients with early-onset periodontitis (EOP) are susceptible to infection with periodontopathic bacteria, such as Porphyromonas gingivalis . Ag53, 53-kDa outer membrane protein of P . gingivalis, evokes strong humoral immune responses in EOP patients . In a first step to clarify how host immune cells recognize Ag53, we established Ag53-specific short-term T cell lines from 22 subjects including 6 EOP patients and 16 healthy donors, using overlapping peptides based on Ag53 amino acid sequences . All T cell lines from active EOP patients recognized a common region (p141-181, especially p141-161) on Ag53, while those from healthy donors showed heterogeneous specificity . p141-181 was not recognized by T cell lines established from EOP patients following therapy . A monoclonal antibody to HLA-DRB 1 inhibited Ag53-induced proliferation of most of the T cell lines . Our observations suggest that, although antigen-presenting molecules are common in EOP patients and in healthy individuals, p141-161 includes a major T cell epitope(s) on Ag53 for active EOP patients but not for healthy individuals or inactive EOP patients.

Trends Biochem Sci, 1998 Aug, 23(8), 273 - 7
Novel homologs of replication protein A in archaea: implications for the evolution of ssDNA-binding proteins; Chedin F et al.; In Bacteria and Eukarya, ssDNA-binding proteins are central to most aspects of DNA metabolism . Until recently, however, no counterpart of an ssDNA-binding protein had been identified in the third domain of life, Archaea . Here, we report the discovery of a novel type of ssDNA-binding protein in the genomes of several archaeons . These proteins, in contrast to all known members of this protein family, possess four conserved DNA-binding sites within a single polypeptide or, in one case, two polypeptides . This peculiar structural organization allows us to propose a model for the evolution of this class of proteins.

Biosci Biotechnol Biochem, 1998 Aug, 62(8), 1504 - 9
Effect of indigestible oligosaccharides on the hepatotoxic action of D-galactosamine in rats; Wang B et al.; The effects of dietary oligosaccharides on the hepatotoxic action of D-galactosamine (GalN) were investigated in this study . Male Wistar rats fed with 20% casein diets containing 10% oligosaccharide or D-galactose (Gal) for 2 weeks were injected with GalN (1,900 mg/kg of body weight), and the plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and the hepatic glycogen concentration were examined 20 hours after the injection . The plasma AST and ALT activities in experiment 1 for the Gal + neomycin (NEO) group were significantly lower than those for the control (C), NEO, raffinose (RAF) + NEO and galacto-oligosaccharide (GA-LO) + NEO groups . In experiment 2, these activities were significantly lower in the Gal, Gal + NEO and RAF groups than in the RAF + NEO group when the groups were treated with GalN . On the other hand, in respect of the hepatic glycogen concentration in experiment 1, that of the Gal + NEO group was higher than that of the C, NEO, RAF + NEO or GALO + NEO groups . In experiment 2, this parameter was significantly higher in the Gal, Gal + NEO and RAF groups than in the RAF + NEO group after the GalN treatment . As a result, it is suggested that the GalN-hepatitis-suppressive effects of indigestible oligosaccharides such as RAF or GALO is mediated by the action of intestinal bacteria.

Genetics, 1998 Oct, 150(2), 767 - 75
The correlation between synonymous and nonsynonymous substitutions in Drosophila: mutation, selection or relaxed constraints?
Comeron JM, Kreitman M.
Codon usage bias, the preferential use of particular codons within each codon family, is characteristic of synonymous base composition in many species, including Drosophila, yeast, and many bacteria . Preferential usage of particular codons in these species is maintained by natural selection acting largely at the level of translation . In Drosophila, as in bacteria, the rate of synonymous substitution per site is negatively correlated with the degree of codon usage bias, indicating stronger selection on codon usage in genes with high codon bias than in genes with low codon bias . Surprisingly, in these organisms, as well as in mammals, the rate of synonymous substitution is also positively correlated with the rate of nonsynonymous substitution . To investigate this correlation, we carried out a phylogenetic analysis of substitutions in 22 genes between two species of Drosophila, Drosophila pseudoobscura and D . subobscura, in codons that differ by one replacement and one synonymous change . We provide evidence for a relative excess of double substitutions in the same species lineage that cannot be explained by the simultaneous mutation of two adjacent bases . The synonymous changes in these codons also cannot be explained by a shift to a more preferred codon following a replacement substitution . We, therefore, interpret the excess of double codon substitutions within a lineage as being the result of relaxed constraints on both kinds of substitutions in particular codons.

Genetics, 1998 Oct, 150(2), 633 - 41
Regulation of gene expression during the vegetative incompatibility reaction in Podospora anserina . Characterization of three induced genes; Bourges N et al.; Vegetative incompatibility in fungi limits the formation of viable heterokaryons . It results from the coexpression of incompatible genes in the heterokaryotic cells and leads to a cell death reaction . In Podospora anserina, a modification of gene expression takes place during this reaction, including a strong decrease of total RNA synthesis and the appearance of a new set of proteins . Using in vitro translation of mRNA and separation of protein products by two-dimensional gel electrophoresis, we have shown that the mRNA content of cells is qualitatively modified during the progress of the incompatibility reaction . Thus, gene expression during vegetative incompatibility is regulated, at least in part, by variation of the mRNA content of specific genes . A subtractive cDNA library enriched in sequences preferentially expressed during incompatibility was constructed . This library was used to identify genomic loci corresponding to genes whose mRNA is induced during incompatibility . Three such genes were characterized and named idi genes for genes induced during incompatibility . Their expression profiles suggest that they may be involved in different steps of the incompatibility reaction . The putative IDI proteins encoded by these genes are small proteins with signal peptides . IDI-2 protein is a cysteine-rich protein . IDI-2 and IDI-3 proteins display some similarity in a tryptophan-rich region.

EMBO J, 1998 Oct 1, 17(19), 5757 - 65
Srb/mediator proteins interact functionally and physically with transcriptional repressor Sfl1; Song W et al.; Srb/mediator proteins that are associated with RNA polymerase II holoenzyme have been implicated in transcriptional repression in Saccharomyces cerevisiae . We show here that the defect in repression of SUC2 caused by mutation of SRB8, SRB9, SRB11, SIN4 or ROX3 is suppressed by increased dosage of the SFL1 gene, and the genetic behavior of the sfl1Delta mutation provides further evidence for a functional relationship . Sfl1 acts on SUC2 through a repression site located immediately 5' to the TATA box, and Sfl1 binds this DNA sequence in vitro . Moreover, LexA-Sfl1 represses transcription of a reporter, and repression is reduced in an srb9 mutant . Finally, we show that Sfl1 co-immunoprecipitates from cell extracts with Srb9, Srb11, Sin4 and Rox3 . We propose that Sfl1, when bound to its site, interacts with Srb/mediator proteins to inhibit transcription by RNA polymerase II holoenzyme.

Eur J Cardiothorac Surg, 1998 Aug, 14(2), 191 - 6
Lung transplantation for cystic fibrosis--a single center experience over 8 years; Wiebe K et al.; OBJECTIVE: Colonization of the lung and mediastinal lymph nodes with multi-resistant bacteria, diabetes and malnutrition represent potential risk factors for lung transplantation in cystic fibrosis . We therefore reviewed our experience in this patient population . METHODS: Between December 1988 and March 1997, 219 lung and heart-lung transplantations were performed at our institution . Of these, 39 procedures were done in 35 patients with cystic fibrosis . All candidates (mean age 26 years) were oxygen dependent (preoperative mean PO2: 44.8 +/- 9.1 Torr, preoperative mean PCO2: 53.4 +/- 10.5 Torr, one patient on respirator) . Of the primary operations, 34 were performed as bilateral sequential lung transplants, one as a heart-lung transplantation . RESULTS: Mean duration on respirator for survivors was 3.1 (1-12) days, mean ICU and hospital stay were 4.7 (1-13) and 28 (12-79) days, respectively . The 3-month mortality rate was 5.7% (two patients died due to acute graft failure on days 36 and 73) . Other causes of death in the follow-up were cerebral bleeding (one patient) and chronic graft failure (three patients) . The survival rates were 91% at 1 year, 83% at 3 years and 76% at 5 years . In eight patients, a bronchiolitis obliterans syndrome (BOS) developed (in four cases grade 3) . The freedom of BOS (grade 1 or more) at 1, 3 and 5 years was 87, 79 and 55%, respectively . Four retransplantations were performed . Of the 29 patients alive, only seven are physically limited . CONCLUSION: Bilateral lung transplantation for cystic fibrosis allows for acceptable early- and long-term results . Postoperative survival is not impaired by infection, diabetes and malnutrition . Long-term functional outcome seems to be comparable to lung transplantation in patients without infectious pulmonary disease.

Biochem Biophys Res Commun, 1998 Sep 18, 250(2), 403 - 8
Use of fluorescein labelled antibody and fluorescence activated cell sorter for rapid identification of Mycobacterium species; Yi WC et al.; A fluorescein labelled antibody (Ab)/Fluorescence Activated Cell Sorter (FACS)-based assay was developed for detection of a wide range of mycobacterial species directly from bacterial culture and sputum specimens . The whole process could be completed within 3 hours and had a high specificity and sensitivity for cultured bacteria . The method was also shown to be applicable for direct identification from clinical specimens . This study showed that pretesting of clinical specimens for mycobacteria to the genus level with an antibody to Mycobacterium species offers the routine clinical laboratory a single convenient test for the detection of tuberculous and nontuberculous mycobacteria . Depending on the availability of species-specific antibody, the identification of Mycobacterium to the species level can be achieved.

J Pept Sci, 1998 Aug, 4(5), 364 - 8
Trans-cis amide bond isomerization in fulleroprolines; Bianco A et al.; The 1H NMR study of fulleroproline derivative Ac-Fpr-OtBu and its Pro analogue Ac-L-Pro-OtBu over a range of temperatures in toluene-d8 solution has enabled the comparison of their equilibrium and activation parameters for the trans/cis interconversion around the amide partial double bond.

Biochemistry, 1998 Sep 29, 37(39), 13643 - 9
A polar octapeptide fused to the N-terminal fusion peptide solubilizes the influenza virus HA2 subunit ectodomain; Chen J et al.; As a step toward studying membrane fusion with a simplified molecule, the ectodomain, residues 1-185, of the membrane-anchored subunit HA2 of the influenza virus haemagglutinin (HA) was solubilized by adding the very polar FLAG octapeptide (Asp-Tyr-Lys-Asp-Asp-Asp-Asp-Lys) to the N-terminal HA2 fusion peptide . The resulting chimeric protein, F185, when expressed in bacteria, folded spontaneously into a soluble trimer, with a high alpha-helical content and a high melting temperature, structural characteristics of the low-pH-induced conformation of HA2 . Removal of the FLAG octapeptide by proteolysis with enterokinase converted the soluble molecule to one that aggregated, bound nonionic detergent, and bound to lipid vesicles, properties of the low-pH-induced conformation of HA . Thermolysin treatment of the aggregated protein removed the nonpolar fusion peptide, regenerating soluble trimers of HA2 (residues 24-185), which is analogous to thermolysin treatment of HA in the low-pH-induced conformation . Thermolysin treatment also dissociates F185 from the detergent-protein complex by removing the fusion peptide . These results suggest that highly polar peptides can be fused to the membrane-binding regions of membrane proteins to increase their solubility . They also indicate that ectodomains of HA2 made in bacteria have membrane-binding properties similar to those of the same ectodomain generated by low-pH treatment of HA isolated from virus.

Dig Dis Sci, 1998 Sep, 43(9 Suppl), 181S - 187S
Effect of rebamipide on H . pylori-associated gastric mucosal injury in Mongolian gerbils; Suzuki H et al.; Helicobacter pylori colonized to gastric mucosa plays an important pathogenic role in gastric mucosal lesions . We previously reported that ethanol pretreatment promotes the extension of H . pylori-associated lesions . The present study was designed to examine the effect of rebamipide, a mucosal protective agent, on H . pylori-associated injury . Male Mongolian gerbils were orally inoculated with H . pylori; 30 min prior to inoculation, 40% ethanol was administered orally to these gerbils (Hp group) . Controls were given 40% ethanol with culture medium (control group) . Some gerbils in the Hp and control groups were fed rebamipide-containing diets, and the remaining gerbils received laboratory chow diets . H . pylori infection was evaluated by quantitative bacterial culture and histological examination . Although H . pylori was persistently detected and a remarkable mucosal leukocyte infiltration was observed in the Hp groups, the bacteria had disappeared naturally in 67% of the gerbils and mucosal damage was mitigated in the Hp + rebamipide group at four weeks after the inoculation . Collectively, rebamipide might play a role in inhibiting the level of H . pylori colonization and gastric lesion formation in Mongolian gerbils.

Br J Surg, 1998 Sep, 85(9), 1221 - 4
D-lactate as an early marker of intestinal ischaemia after ruptured abdominal aortic aneurysm repair; Poeze M et al.; BACKGROUND: Patients with a ruptured abdominal aortic aneurysm (AAA) are at risk of developing colonic ischaemia after surgery . It is difficult to diagnose this ischaemia at an early stage . D-lactate is produced by intestinal bacteria after ischaemia . L-lactate is released in increased amounts during hypoxia by anaerobic metabolism . This study investigated both variables as a marker for intestinal ischaemia in patients with a ruptured AAA . METHODS: Twenty-four patients with ruptured AAA were divided retrospectively into two groups with and without ischaemic complications, as verified by colonoscopy . Blood had been taken on admission to the intensive care unit (ICU) . Median time to colonoscopy was 9 days after surgery . As controls, four patients with pneumonia, six healthy subjects, five patients with an elective AAA repair, and six patients with sepsis and acute tubular necrosis were included . RESULTS: D-lactate level on admission was significantly increased in patients with colonic ischaemia after ruptured AAA compared with the level in patients without ischaemia (P< 0.05), patients with sepsis (P< 0.001), those with pneumonia and healthy subjects (P< 0.01) . L-lactate concentration was similar in the group with intestinal complications and in patients without colonic ischaemia; however, L-lactate levels were higher in patients with pneumonia and sepsis than in healthy subjects (P < 0.05) . CONCLUSION: On admission to the ICU, D-lactate, but not L-lactate, levels may predict later colonic ischaemia following repair of a ruptured AAA.

Prog Nucleic Acid Res Mol Biol, 1998, 61, 309 - 44
Structural organization and transcription regulation of nuclear genes encoding the mammalian cytochrome c oxidase complex; Lenka N et al.; Cytochrome c Oxidase (COX) is the terminal component of the bacterial as well as the mitochondrial respiratory chain complex that catalyzes the conversion of redox energy to ATP . In eukaryotes, the oligomeric enzyme is bound to mitochondrial innermembrane with subunits ranging from 7 to 13 . Thus, its biosynthesis involves a coordinate interplay between nuclear and mitochondrial genomes . The largest subunits, I, II, and III, which represent the catalytic core of the enzyme, are encoded by the mitochondrial DNA and are synthesized within the mitochondria . The rest of the smaller subunits implicated in the regulatory function are encoded on the nuclear DNA and imported into mitochondria following their synthesis in the cytosol . Some of the nuclear coded subunits are expressed in tissue and developmental specific isologs . The ubiquitous subunits IV, Va, Vb, VIb, VIc, VIIb, VIIc, and VIII (L) are detected in all the tissues, although the mRNA levels for the individual subunits vary in different tissues . The tissue specific isologs VIa (H), VIIa (H), and VIII (H) are exclusive to heart and skeletal muscle . cDNA sequence analysis of nuclear coded subunits reveals 60 to 90% conservation among species both at the amino acid and nucleotide level, with the exception of subunit VIII, which exhibits 40 to 80% interspecies homology . Functional genes for COX subunits IV, Vb, VIa 'L' & 'H', VIIa 'L' & 'H', VIIc and VIII (H) from different mammalian species and their 5' flanking putative promoter regions have been sequenced and extensively characterized . The size of the genes range from 2 to 10 kb in length . Although the number of introns and exons are identical between different species for a given gene, the size varies across the species . A majority of COX genes investigated, with the exception of muscle-specific COXVIII(H) gene, lack the canonical 'TATAA' sequence and contain GC-rich sequences at the immediate upstream region of transcription start site(s) . In this respect, the promoter structure of COX genes resemble those of many house-keeping genes . The ubiquitous COX genes show extensive 5' heterogeneity with multiple transcription initiation sites that bind to both general as well as specialized transcription factors such as YY1 and GABP (NRF2/ets) . The transcription activity of the promoter in most of the ubiquitous genes is regulated by factors binding to the 5' upstream Sp1, NRF1, GABP (NRF2), and YY1 sites . Additionally, the murine COXVb promoter contains a negative regulatory region that encompasses the binding motifs with partial or full consensus to YY1, GTG, CArG, and ets . Interestingly, the muscle-specific COX genes contain a number of striated muscle-specific regulatory motifs such as E box, CArG, and MEF2 at the proximal promoter regions . While the regulation of COXVIa (H) gene involves factors binding to both MEF2 and E box in a skeletal muscle-specific fashion, the COXVIII (H) gene is regulated by factors binding to two tandomly duplicated E boxes in both skeletal and cardiac myocytes . The cardiac-specific factor has been suggested to be a novel bHLH protein . Mammalian COX genes provide a valuable system to study mechanisms of coordinated regulation of nuclear and mitochondrial genes . The presence of conserved sequence motifs common to several of the nuclear genes, which encode mitochondrial proteins, suggest a possible regulatory function by common physiological factors like heme/O2/carbon source . Thus, a well-orchestrated regulatory control and cross talks between the nuclear and mitochondrial genomes in response to changes in the mitochondrial metabolic conditions are key factors in the overall regulation of mitochondrial biogenesis.

Recent Dev Alcohol, 1998, 14, 67 - 95
Alcohol and cancer; Seitz HK et al.; A great number of epidemiological data have identified chronic alcohol consumption as a significant risk factor for upper alimentary tract cancer, including cancer of the oropharynx, larynx, and the esophagus, and for the liver . In contrast to those organs, the risk by which alcohol consumption increases cancer in the large intestine and in the breast is much smaller . However, although the risk is lower, carcinogenesis can be enhanced with relatively low daily doses of ethanol . Considering the high prevalence of these tumors, even a small increase in cancer risk is of great importance, especially in those individuals who exhibit a higher risk for other reasons . The epidemiological data on alcohol and other organ cancers are controversial and there is at present not enough evidence for a significant association . Although the exact mechanisms by which chronic alcohol ingestion stimulates carcinogenesis are not known, experimental studies in animals support the concept that ethanol is not a carcinogen, but under certain experimental conditions is a cocarcinogen and/or (especially in the liver) a tumor promoter . The metabolism of ethanol leads to the generation of acetaldehyde and free radicals . These highly reactive compounds bind rapidly to cell constituents and possibly to DNA . Acetaldehyde decreases DNA repair mechanisms and the methylation of cytosine in DNA . It also traps glutathione, an important peptide in detoxification . Furthermore, it leads to chromosomal aberrations and seems to be associated with tissue damage and secondary compensatory hyperregeneration . More recently, the finding of considerable production of acetaldehyde by gastrointestinal bacteria was reported . Other mechanisms by which alcohol stimulates carcinogenesis include the induction of cytochrome P4502E1, associated with an enhanced activation of various procarcinogens present in alcoholic beverages, in association with tobacco smoke and in diets, a change in the metabolism and distribution of carcinogens, alterations in cell cycle behavior such as cell cycle duration leading to hyperregeneration, nutritional deficiencies such as methyl, vitamin A, folate, pyrridoxalphosphate, zinc and selenium deficiency, and alterations of the immune system, eventually resulting in an increased susceptibility to certain viral infections such as hepatitis B virus and hepatitis C virus . In addition, local mechanisms in the upper gastrointestinal tract and in the rectum may be of particular importance . Such mechanisms lead to tissue injury such as cirrhosis of the liver, a major prerequisite for hepatocellular carcinoma . Thus, all these mechanisms, functioning in concert, actively modulate carcinogenesis, leading to its stimulation.

Proc Natl Acad Sci U S A, 1998 Sep 29, 95(20), 11745 - 50
The common marmoset: a new world primate species with limited Mhc class II variability; Antunes SG et al.; The common marmoset (Callithrix jacchus) is a New World primate species that is highly susceptible to fatal infections caused by various strains of bacteria . We present here a first step in the molecular characterization of the common marmoset's Mhc class II genes by nucleotide sequence analysis of the polymorphic exon 2 segments . For this study, genetic material was obtained from animals bred in captivity as well as in the wild . The results demonstrate that the common marmoset has, like other primates, apparently functional Mhc-DR and -DQ regions, but the Mhc-DP region has been inactivated . At the -DR and -DQ loci, only a limited number of lineages were detected . On the basis of the number of alleles found, the -DQA and -B loci appear to be oligomorphic, whereas only a moderate degree of polymorphism was observed for two of three Mhc-DRB loci . The contact residues in the peptide-binding site of the Caja-DRB1*03 lineage members are highly conserved, whereas the -DRB*W16 lineage members show more divergence in that respect . The latter locus encodes five oligomorphic lineages whose members are not observed in any other primate species studied, suggesting rapid evolution, as illustrated by frequent exchange of polymorphic motifs . All common marmosets tested were found to share one monomorphic type of Caja-DRB*W12 allele probably encoded by a separate locus . Common marmosets apparently lack haplotype polymorphism because the number of Caja-DRB loci present per haplotype appears to be constant . Despite this, however, an unexpectedly high number of allelic combinations are observed at the haplotypic level, suggesting that Caja-DRB alleles are exchanged frequently between chromosomes by recombination, promoting an optimal distribution of limited Mhc polymorphisms among individuals of a given population . This peculiar genetic make up, in combination with the limited variability of the major histocompatability complex class II repertoire, may contribute to the common marmoset's susceptibility to particular bacterial infections.

J Appl Microbiol, 1998 Sep, 85(3), 448 - 56
Growth characteristics and metabolic activities of the methanotrophic-heterotrophic groundwater community; Hrsak D et al.; In this work the growth characteristics and metabolic activities of the methanotrophic-heterotrophic groundwater community (culture MM1) as well as of individual community members were studied . When growing in shake flasks, under various methane and oxygen tensions, culture MM1 revealed the capability of a stable association consisting of one obligate methanotroph with type II intracytoplasmic membranes as the dominant strain, and four or five heterotrophs of different morphological, physiological and metabolic characteristics . Coexistence of different populations and the stability of culture MM1 under various conditions suggested that complex relationships may exist between the community members . Most of these relationships seem to be beneficial for both the methanotroph and heterotrophs, making the community adaptable to a range of environmental conditions containing methane as the only carbon source . Furthermore, faster and more complete transformation of 2-{4-(sulphophenyl)}decane (2C10LAS) by the community than by any of the community members alone, illustrates the role and importance of methanotrophic-heterotrophic interactions in combined metabolic attack on complex linear alkylbenzenesulphonates molecules.

JAMA, 1998 Sep 16, 280(11), 981 - 8
Chronic multisymptom illness affecting Air Force veterans of the Gulf War; Fukuda K et al.; CONTEXT: Gulf War (GW) veterans report nonspecific symptoms significantly more often than their nondeployed peers . However, no specific disorder has been identified, and the etiologic basis and clinical significance of their symptoms remain unclear . OBJECTIVES: To organize symptoms reported by US Air Force GW veterans into a case definition, to characterize clinical features, and to evaluate risk factors . DESIGN: Cross-sectional population survey of individual characteristics and symptoms and clinical evaluation (including a structured interview, the Medical Outcomes Study Short Form 36, psychiatric screening, physical examination, clinical laboratory tests, and serologic assays for antibodies against viruses, rickettsia, parasites, and bacteria) conducted in 1995 . PARTICIPANTS AND SETTING: The cross-sectional questionnaire survey included 3723 currently active volunteers, irrespective of health status or GW participation, from 4 air force populations.The cross-sectional clinical evaluation included 158 GW veterans from one unit, irrespective of health status . MAIN OUTCOME MEASURES: Symptom-based case definition; case prevalence rate for GW veterans and nondeployed personnel; clinical and laboratory findings among veterans who met the case definition . RESULTS: We defined a case as having 1 or more chronic symptoms from at least 2 of 3 categories (fatigue, mood-cognition, and musculoskeletal) . The prevalence of mild-to-moderate and severe cases was 39% and 6%, respectively, among 1155 GW veterans compared with 14% and 0.7% among 2520 nondeployed personnel . Illness was not associated with time or place of deployment or with duties during the war . Fifty-nine clinically evaluated GW veterans (37%) were noncases, 86 (54%) mild-to-moderate cases, and 13 (8%) severe cases . Although no physical examination, laboratory, or serologic findings identified cases, veterans who met the case definition had significantly diminished functioning and well-being . CONCLUSIONS: Among currently active members of 4 Air Force populations, a chronic multisymptom condition was significantly associated with deployment to the GW . The condition was not associated with specific GW exposures and also affected nondeployed personnel.

J Bacteriol, 1998 Oct, 180(19), 5251 - 5
Bradyrhizobium japonicum FixK2, a crucial distributor in the FixLJ-dependent regulatory cascade for control of genes inducible by low oxygen levels; Nellen-Anthamatten D et al.; Bradyrhizobium japonicum possesses a second fixK-like gene, fixK2, in addition to the previously identified fixK1 gene . The expression of both genes depends in a hierarchical fashion on the low-oxygen-responsive two-component regulatory system FixLJ, whereby FixJ first activates fixK2, whose product then activates fixK1 . While the target genes for control by FixK1 are unknown, there is evidence for activation of the fixNOQP, fixGHIS, and rpoN1 genes and some heme biosynthesis and nitrate respiration genes by FixK2 . FixK2 also regulates its own structural gene, directly or indirectly, in a negative way.

J Bacteriol, 1998 Oct, 180(19), 5070 - 6
Poly-beta-hydroxybutyrate turnover in Azorhizobium caulinodans is required for growth and affects nifA expression; Mandon K et al.; Azorhizobium caulinodans is able to fix nitrogen in the free-living state and in symbiosis with the tropical legume Sesbania rostrata . The bacteria accumulate poly-beta-hydroxybutyrate (PHB) under both conditions . The structural gene for PHB synthase, phbC, was inactivated by insertion of an interposon . The mutant strains obtained were devoid of PHB, impaired in their growth properties, totally devoid of nitrogenase activity ex planta (Nif-), and affected in nucleotide pools and induced Fix- nodules devoid of bacteria . The Nif- phenotype was the consequence of the lack of nifA transcription . Nitrogenase activity was partially restored to a phbC mutant by constitutive expression of the nifA gene . However, this constitutive nifA expression had no effect on the nucleotide content or on growth of the phbC mutant . It is suggested that PHB is required for maintaining the reducing power of the cell and therefore the bacterial growth . These observations also suggest a new control of nifA expression to adapt nitrogen fixation to the availability of carbon and reducing equivalents.

J Bacteriol, 1998 Oct, 180(19), 5044 - 51
Sucrose is a nonaccumulated osmoprotectant in Sinorhizobium meliloti; Gouffi K et al.; Intracellular accumulation of sucrose in response to lowered water activity seems to occur only in photosynthetic organisms . Here we demonstrate, for the first time, the potent ability of this common sugar, supplied exogenously, to reduce growth inhibition of Sinorhizobium meliloti cells in media of inhibitory osmolarity . Independently of the nature of the growth substrates and the osmotic agent, sucrose appears particularly efficient in promoting the recovery of cytoplasmic volume after plasmolysis . Surprisingly, sucrose is not accumulated by the bacteria at an osmotically efficient level . Instead, it strongly stimulates the accumulation of the main endogenous osmolytes glutamate and N-acetylglutaminylglutamine amide (NAGGN) . Examining cell volume changes during the hyperosmotic treatment, we found a close correlation between the enhancement of the osmotically active solute pool and the increase in cell volume . Sucrose shares several features with ectoine, another nonaccumulated osmoprotectant for S . meliloti . Overall, osmoregulation in S . meliloti appears to be strongly divergent from that in most bacteria.

J Nat Prod, 1998 Sep, 61(9), 1174 - 6
Isolation and synthesis of an alpha-malamic acid derivative from Justicia ghiesbreghtiana; Ismail LD et al.; A polar extract of leaves of Justicia ghiesbreghtiana yielded N-(2-hydroxy-4,5-dimethoxyphenyl)-(S)-alpha-malamic acid, 1 . Incomplete spectral analysis yielded a hypothetical structure, which was then proven by total synthesis . Coupling of the trifluoroacetate of malic anhydride (trifluoroacetoxysuccinic anhydride) with an arylamine provided the key to regiospecific preparation of the alpha- rather than beta-malamic acids.

Trends Microbiol, 1998 Aug, 6(8), 323 - 7
beta-Lactamases: protein evolution in real time; Petrosino J et al.; The evolution and spread of bacteria resistant to beta-lactam antibiotics has progressed at an alarming rate . Bacteria may acquire resistance to a given drug by mutation of pre-existing genes or by the acquisition of new genes from other bacteria . One ongoing example of these mechanisms is the evolution of new variants of the TEM and SHV beta-lactamases with altered substrate specificity.

J Biol Chem, 1998 Oct 2, 273(40), 25556 - 9
Heparan sulfate/heparin N-deacetylase/N-sulfotransferase . The N-sulfotransferase activity domain is at the carboxyl half of the holoenzyme; Berninsone P et al.; Glycosaminoglycan N-acetylglucosaminyl N-deacetylases/N-sulfotransferases are structurally related enzymes that play an important role in the biosynthesis of heparan sulfate and heparin . They are dual catalytic, single membrane-spanning polypeptides of approximately 850-880 amino acids that catalyze the N-deacetylation of N-acetylglucosamine of glycosaminoglycans followed by N-sulfation of the same sugar . On the basis of homologies of these proteins with other N-acetylglucosaminyl N-deacetylases involved in the biosynthesis of chitin and putative deacetylases from bacteria, we have constructed two soluble chimeras between protein A and the amino- and carboxyl-terminal halves of the above mastocytoma holoenzyme . The carboxyl-terminal chimera half (amino acids 479-880) was able to catalyze the N-sulfation of glucosamine of heparan sulfate with a similar affinity for its two substrates, adenosine 3'-phosphate 5'-phosphosulfate and heparan sulfate, as the holoenzyme . However, the reaction only occurred at 30 degreesC and not at 37 degreesC, both temperatures at which the holoenzyme was active . The Vmax of the chimera was 10-20-fold slower than that of the holoenzyme . Soluble chimeras between protein A and amino acids 43-521 and 43-680 of the holoenzyme were unable to catalyze the N-deacetylation of the bacterial N-acetylglucosaminyl-glucuronic acid polymer K5 under conditions where the holoenzyme was active . The recent appearance in genome data banks of homologs to the N-sulfotransferase domain and now the direct demonstration that this domain catalyzes this reaction raises the possibility that both N-deacetylation and N-sulfation activities of the holoenzyme might have emerged as gene fusions during evolution.

Arch Ophthalmol, 1998 Sep, 116(9), 1195 - 8
Disinfection of eyelid speculums for retinopathy of prematurity examination; Woodman TJ et al.; OBJECTIVE: To evaluate the effectiveness of 70% isopropyl alcohol swabs in disinfecting eyelid speculums after examination for retinopathy of prematurity . METHODS: Two phases . Phase 1: 46 autoclave-sterilized eyelid speculums randomized into either a cleaned or control group following examination for retinopathy of prematurity . Speculums in the cleaned group were disinfected with a 70% isopropyl alcohol swab while control speculums were not cleaned . Bacterial and fungal cultures were then obtained . Phase 2: 20 autoclave-sterilized eyelid speculums inoculated with a clinically relevant dilution of adenovirus serotype 5 or herpes simplex virus type 2 . Inoculated speculums were randomized into either a cleaned or control group . RESULTS: Phase 1: 17 (70.8%) of 24 cultures from the cleaned group yielded bacteria compared with 21 (95.5%) of 22 controls . Fungi were isolated from only 1 control and from no cleaned speculums . Phase 2: all speculums inoculated with adenovirus supported growth of the organism irrespective of cleaning with 70% isopropyl alcohol swabs . None of 5 cleaned speculums inoculated with herpes simplex virus type 2 supported viral growth, compared with 3 (60%) of 5 cultures positive for growth in the control group . CONCLUSION: Cleaning eyelid speculums with 70% isopropyl alcohol swabs provided inadequate disinfection against bacteria following examination for retinopathy of prematurity and against adenovirus in a laboratory simulation.

Infect Immun, 1998 Oct, 66(10), 4602 - 10
Surface-associated hsp60 chaperonin of Legionella pneumophila mediates invasion in a HeLa cell model; Garduno RA et al.; HeLa cells have been previously used to demonstrate that virulent strains of Legionella pneumophila (but not salt-tolerant avirulent strains) efficiently invade nonphagocytic cells . Hsp60, a member of the GroEL family of chaperonins, is displayed on the surface of virulent L . pneumophila (R . A . Garduno et al., J . Bacteriol . 180:505-513, 1988) . Because Hsp60 is largely involved in protein-protein interactions, we investigated its role in adherence-invasion in the HeLa cell model . Hsp60-specific antibodies inhibited the adherence and invasiveness of two virulent L . pneumophila strains in a dose-dependent manner but had no effect on the association of their salt-tolerant avirulent derivatives with HeLa cells . A monospecific anti-OmpS (major outer membrane protein) serum inhibited the association of both virulent and avirulent strains of L . pneumophila to HeLa cells, suggesting that while both Hsp60 and OmpS may mediate bacterial association to HeLa cells, only virulent strains selectively displayed Hsp60 on their surfaces . Furthermore, the surface-associated Hsp60 of virulent bacterial cells was susceptible to the action of trypsin, which rendered the bacteria noninvasive . Additionally, pretreatment of HeLa cells with purified Hsp60 or precoating of the plastic surface where HeLa cells attached with Hsp60 reduced the adherence and invasiveness of the two virulent strains . Finally, recombinant Hsp60 covalently bound to latex beads promoted the early association of beads with HeLa cells by a factor of 20 over bovine serum albumin (BSA)-coated beads and competed with virulent strains for association with HeLa cells . Hsp60-coated beads were internalized in large numbers by HeLa cells and remained in tight endosomes that did not fuse with other vesicles, whereas internalized BSA-coated beads, for which endocytic trafficking is well established, resided in more loose or elongated endosomes . Mature intracellular forms of L . pneumophila, which were up to 100-fold more efficient than agar-grown bacteria at associating with HeLa cells, were enriched for Hsp60 on the bacterial surface, as determined by immunolocalization techniques . Collectively, these results establish a role for surface-exposed Hsp60 in invasion of HeLa cells by L . pneumophila.

Biophys J, 1998 Oct, 75(4), 1997 - 2003
A DNA self-assembled monolayer for the specific attachment of unmodified double- or single-stranded DNA; Bamdad C; A novel method for DNA surface immobilization and a paradigm for the attachment of unmodified DNA of any length or sequence are described herein . The development of a DNA self-assembled monolayer (DNA-SAM) that incorporates a DNA-thiol into a monolayer of inert alkane thiolates is reported . This DNA-SAM specifically hybridized complementary oligonucleotides while resisting the nonspecific adsorption of noncomplementary DNA and irrelevant proteins . Duplex DNA, having a single-stranded "capture tail," specifically bound to the DNA-SAM if the sequence of the "tail" was complementary to DNA presented in the SAM . The sense strand of the hybridized duplex DNA could be covalently attached to the surface by an enzymatic ligation reaction (leaving the anti-sense strand dissociable) . DNA-binding proteins specifically bound to these surfaces only if their cognate sites were present in the duplex DNA.

Eur J Biochem, 1998 Aug 15, 256(1), 36 - 44
Functional expression of eukaryotic polypeptide chain release factors 1 and 3 by means of baculovirus/insect cells and complex formation between the factors; Frolova LY et al.; Translation termination in eukaryotes is governed by termination codons in mRNA and two release factors, eRF1 and eRF3 . In this work, human eRF1 and eRF3 have been produced in insect cells using a recombinant baculovirus expression system for the corresponding human cDNAs . Purification of eRF1 has led to a homogeneous 50-kDa protein active in promoting ribosome-dependent and termination-codon-dependent hydrolysis of formylmethionyl-tRNAf(Met) . Purification of eRF3 yielded a full-length protein and shorter polypeptides . Microsequencing of the N-terminus of the shortest form detected a site of proteolytic cleavage between Arg91 and Gly92, probably due to exposed region(s) hypersensitive to proteolysis . The mixture of full-length and truncated forms of eRF3 as well as bacterially expressed eRF3 lacking 138 N-terminal amino acids (eRF3Cp) are active as an eRF1-dependent and ribosome-dependent GTPase and in stimulating the GTP-dependent release activity of eRF1 . Complex formation between eRF1 and eRF3Cp was demonstrated by affinity and gel-filtration chromatographies and by native-gel electrophoresis . An abnormal electrophoretic mobility observed for eRF1 as compared with the complex points to a significant conformational change of either eRF1 or both factors in the complex . Co-expression of both factors in baculovirus-infected insect cells and a yeast two-hybrid assay were applied to monitor complex formation in vivo . In yeast cells, both eRF1 and eRF3 are either in a monomeric or in a heterodimeric but not in a homodimeric state.

Vet Parasitol, 1998 Jun 15, 77(2-3), 179 - 86
Experimental infection of dogs with the nasal mite Pneumonyssoides caninum; Gunnarsson L et al.; A successful experimental transmission of the canine nasal mite, Pneumonyssoides caninum, is described . Some 11 weeks after repeated systemic ivermectin treatment, four Beagles were inoculated via the right nostril with 20 P . caninum mites of different sexes and life stages, obtained at the necropsy of an infected dog . The inoculated dogs and a matching uninoculated control were observed for clinical signs for 14 weeks and then euthanised . Vague upper respiratory signs and a transient minor increase in the number of eosinophils in peripheral blood were recorded in the inoculated dogs . At necropsy 4-12 P . caninum mites were found in the nasal cavities and sinuses of the inoculated dogs, but none in the control . In three out of the four infected dogs mites were found in both the right and left nasal cavities and sinuses of the skull . Since in no case more mites than the number used for inoculation were detected it is not clear if the mites managed to reproduce in the dogs . Inflammatory lesions were seen most consistently in the olfactory mucosa, respiratory mucosa and tonsils, and growth of opportunistic bacteria was observed in the tonsils of the infected dogs . The inflammatory lesions seen in the olfactory mucosa may explain why dogs infected with P . caninum sometimes appear to suffer from impaired scenting ability.

Kansenshogaku Zasshi, 1998 Jul, 72(7), 753 - 60
Increased production of interleukin-10 by human blood monocytes stimulated with Mycobacterium avium-intracellulare complex; Ueda W et al.; Macrophages produce various cytokines in response to mycobacteria, including interleukin 10 (IL-10) and tumor necrosis factor alpha (TNF-alpha) . IL-10 has been shown to down-regulate numerous macrophage functions, including microbicidal activity against intracellular bacteria and parasites . IL-10 also inhibits interferon-gamma (IFN-gamma) production and antigen-specific proliferation of Th1 cells mediating immunologic resistance to mycobacterial infection . In contrast, TNF-alpha activates macrophages and may augment their mycobacterial activity . In this study, peripheral blood mononuclear cells (PBMC) or blood monocytes obtained from healthy tuberculin reactors were stimulated in vitro with heat-killed Mycobacterium tuberculosis or heat-killed M . avium-intracellulare complex (MAC) to produce IL-10 and TNF-alpha . We studied a total of 26 clinical isolates of M . tuberculosis and 28 isolates of MAC . MAC-stimulated PBMC and monocytes released significantly larger amounts of IL-10 than those cells stimulated with M . tuberculosis . However, there was no difference in induction of TNF-alpha production between MAC and M . tuberculosis . When TNF-activity was neutralized by the addition of anti-TNF-alpha mAb in culture, MAC still induced more IL-10 secretion than did M . tuberculosis . These findings suggest that increased production of IL-10 by MAC-stimulated monocytes may play a role in the intractable disease caused by these organisms.

J Am Vet Med Assoc, 1998 Sep 15, 213(6), 862 - 5
Histologic features and results of virus isolation tests of tissues obtained from teat lesions that developed in dairy cattle during winter; Timms LL et al.; OBJECTIVE: To determine microscopic features and involvement of viruses in teat-end lesions (TEL) of dairy cows during winter . SAMPLE POPULATION: Teats with TEL on lactating Holstein cows and from udders of carcasses . PROCEDURE: Tissues obtained from TEL of 10 teats from 7 cows on 2 research farms during the winter of 1994 to 1995 and 13 teats with TEL excised from udders of carcasses at an abattoir during February 1995 were submitted for virus isolation . During the winter of 1995 to 1996, an increased prevalence of TEL was observed in a research herd . After a decrease in ambient temperature, TEL were identified, and a full-thickness section of epidermis was removed from skin surrounding teat orifices . Tissues were examined by use of light and electron transmission microscopy . RESULTS: Viruses were not isolated from TEL tissues . Lesions ranged from mild elevations of the epidermis to thickened oval regions that encircled the teat orifice . The most severe lesions were dark and had thick crusts . Histologically, TEL were composed of thickened regions of epidermis most notably caused by hyperplasia of cells within the stratum spinosum . Excess production of keratinocytes was also evident, and the keratinocyte layer often contained bacteria . Ultrastructurally, squamous cells contained large amounts of keratin, but virions were not detected . Evidence of a viral etiologic agent for TEL was not detected . CLINICAL IMPLICATIONS: Development of TEL may be associated with decreases in ambient temperature . Numerous bacteria were evident in the keratin of TEL . Lesions and associated bacteria may predispose cows to mastitis.

Shock, 1998 Sep, 10(3), 203 - 12
The influence of intestinal ischemia and reperfusion on bidirectional intestinal barrier permeability, cellular membrane integrity, proteinase inhibitors, and cell death in rats; Sun Z et al.; Intestinal ischemia and reperfusion injury (I/R) is probably involved in the pathogenesis of intestinal barrier dysfunction, associated with the concomitant translocation of enteric bacteria and toxins and the potential development of multiple organ failure . The intestinal endothelial and epithelial layers play a major role preventing the entry of toxic substances from the gut, but the influence of protease-antiprotease systemic balance on these barrier functions and the relationship between epithelial DNA synthesis, apoptosis, and endothelial and epithelial barrier macromolecule permeability are not fully investigated . Endothelial and epithelial barrier macromolecular permeability, epithelial DNA synthesis, the endothelial and epithelial plasma membrane system, apoptosis and oncosis, plasma levels of proteinase inhibitors, and proenzymes were measured in rats subjected to 20 and 40 min intestinal ischemia and 1, 3, 6, or 12 h reperfusion . Endothelial permeability increased after both 20 and 40 min intestinal ischemia . Epithelial permeability significantly increased during 1-6 h reperfusion after 20 min ischemia and during 1-12 h reperfusion after 40 min ischemia . Epithelial DNA synthesis increased in animals with 20 min ischemia followed by 12 h reperfusion . Plasma levels of prekallikrein, C1-esterase inhibitor, and alpha1-macroglobulin were significantly lower following both 20 and 40 min ischemia from 3 h reperfusion and on . Apoptotic epithelial cells significantly increased in animals subjected to 20 min ischemia followed by 12 h reperfusion . The severity of reperfusion injury in the intestinal endothelial and epithelial barrier seems to correlate with the period of ischemia and the pathway of cell damage and death, together with proteinase-antiproteinase imbalance.

Proc R Soc Lond B Biol Sci, 1998 Aug 22, 265(1405), 1483 - 9
Rapid parapatric speciation on holey adaptive landscapes; Gavrilets S et al.; A classical view of speciation is that reproductive isolation arises as a by-product of genetic divergence . Here, individual-based simulations are used to evaluate whether the mechanisms implied by this view may result in rapid speciation if the only source of genetic divergence are mutation and random genetic drift . Distinctive features of the simulations are the consideration of the complete process of speciation (from initiation until completion), and of a large number of loci, which was only one order of magnitude smaller than that of bacteria . It is demonstrated that rapid speciation on the time-scale of hundreds of generations is plausible without the need for extreme founder events, complete geographic isolation, the existence of distinct adaptive peaks or selection for local adaptation . The plausibility of speciation is enhanced by population subdivision . Simultaneous emergence of more than two new species from a subdivided population is highly probable . Numerical examples relevant to the theory of centrifugal speciation and to the conjectures about the fate of 'ring species' and 'sexual continuums' are presented.

Plant J, 1998 Jul, 15(1), 27 - 38
A xyloglucan oligosaccharide-active, transglycosylating beta-D-glucosidase from the cotyledons of nasturtium (Tropaeolum majus L) seedlings--purification, properties and characterization of a cDNA clone; Crombie HJ et al.; A beta-D-glucosidase has been purified to apparent homogeneity from the cotyledons of germinated nasturtium (Tropaeolum majus L.) seedlings during the mobilization of the xyloglucan stored in the cotyledonary cell walls . The purified protein (Mr 76, 000; a glycoprotein; pl > 9.5; apparent pH optimum 4.5; temperature optimum 30 degrees C) catalysed the hydrolysis of p-nitrophenyl-beta-D-glucopyranoside, cello-oligosaccharides, beta-linked glucose disaccharides, and certain xyloglucan oligosaccharides . Glucose disaccharides with different linkages were hydrolysed at different rates {(1-->3) > (1-->4) > (1-->2) > (1-->6)} with significant transglycosylation occurring in the early stages of the reaction . Cello-oligosaccharide hydrolysis was also accompanied by extensive transglycosylation to give transitory accumulations of higher oligosaccharides . At least some of the glycosyl linkages formed during transglycosylation were (1-->6)-beta . Xyloglucan oligosaccharides xylose-substituted at the non-reducing terminal glucose residue (XXXG, XXLG, XLXG and XLLG, where G is an unsubstituted glucose residue, X is a xylose-substituted glucose residue, and L is a galactosylxylose-substituted glucose residue) were not hydrolysed . Some xyloglucan oligosaccharides with an unsubstituted non-reducing terminal glucose residue (GXXG, GXLG and GXG) were hydrolysed, but others (GLXG and GLLG) were not . This indicated steric hindrance by L but not X substitution at the glucose residue next to the one at the non-reducing end of the oligosaccharide . Hydrolysis of xyloglucan oligosaccharides was not accompanied by transglycosylation . Natural xyloglucan subunit oligosaccharides (XXXG, XXLG, XLXG, XLLG) were totally degraded to their monosaccharide components when treated with nasturtium beta-D-galactosidase . (Edwards et al (1988) J . Biol . Chem . 263, 4333-4337), followed by alternations of nasturtium xyloglucan-specific alpha-xylosidase (Fanutti et al (1991) Planta 184, 137-147) and this enzyme . Several extensively overlapping cDNA clones were obtained by RT-PCR and by screening cDNA libraries . A composite, full-length DNA had an open reading frame of 1962 bp, encoding a polypeptide of 654 amino acids, including all N-terminal and internal sequences obtained from the purified beta-glucosidase protein, and a motif resembling plant signal sequences thought to direct proteins to the cell wall . Database searches revealed homology with beta-glucosidases from several sources (plant, bacteria, yeast), notably with glycosylhydrolases of 'Family 3', according to the classification of Henrissat (Henrissat (1991) Biochem . J . 280, 309-316) . There was strong sequence homology with a beta-glucan exo-hydrolase from barley (Hrmova et al . (1996) J . Biol . Chem . 271, 5277-5286) . The nasturtium beta-glucosidase is ascribed a role in xyloglucan mobilization, and its interaction with the alpha-xylosidase and the beta-galactosidase is modelled.

Orig Life Evol Biosph, 1998 Oct, 28(4-6), 539 - 53
The role of gene duplication in the evolution of purine nucleotide salvage pathways; Becerra A et al.; Purine nucleotides are formed de novo by a widespread biochemical route that may be of monophyletic origin, or are synthesized from preformed purine bases and nucleosides through different salvage pathways . Three monophyletic sets of purine salvage enzymes, each of which catalyzes mechanistically similar reactions, can be identified: (a) adenine-, xanthine-, hypoxanthine- and guanine-phosphoribosyltransferases, which are all homologous among themselves, as well as to nucleoside phosphorylases; (b) adenine deaminase, adenosine deaminase, and adenosine monophophate deaminase; and (c) guanine reductase and inosine monophosphate dehydrogenase . These homologies support the idea that substrate specificity is the outcome of gene duplication, and that the purine nucleotide salvage pathways were assembled by a patchwork process that probably took place before the divergence of the three cell domains (Bacteria, Archaea, and Eucarya) . Based on the ability of adenine PRTase to catalyze the condensation of PRPP with 4-aminoimidazole-5-carboxamide (AICA), a simpler scheme of purine nucleotide biosynthesis is presented . This hypothetical route requires the prior evolution of PRPP biosynthesis . Since it has been argued that PRPP, nucleosides, and nucleotides are susceptible to hydrolysis, they are very unlikely prebiotic compounds . If this is the case, it implies that many purine salvage pathways appeared only after the evolution of phosphorylated sugar biosynthetic pathways made ribosides available.

Mol Cell Biol, 1998 Oct, 18(10), 5861 - 7
ADR1-mediated transcriptional activation requires the presence of an intact TFIID complex; Komarnitsky PB et al.; The yeast transcriptional activator ADR1, which is required for ADH2 and other genes' expression, contains four transactivation domains (TADs) . While previous studies have shown that these TADs act through GCN5 and ADA2, and presumably TFIIB, other factors are likely to be involved in ADR1 function . In this study, we addressed the question of whether TFIID is also required for ADR1 action . In vitro binding studies indicated that TADI of ADR1 was able to retain TAFII90 from yeast extracts and TADII could retain TBP and TAFII130/145 . TADIV, however, was capable of retaining multiple TAFIIs, suggesting that TADIV was binding TFIID from yeast whole-cell extracts . The ability of TADIV truncation derivatives to interact with TFIID correlated with their transcription activation potential in vivo . In addition, the ability of LexA-ADR1-TADIV to activate transcription in vivo was compromised by a mutation in TAFII130/145 . ADR1 was found to associate in vivo with TFIID in that immunoprecipitation of either TAFII90 or TBP from yeast whole-cell extracts specifically coimmunoprecipitated ADR1 . Most importantly, depletion of TAFII90 from yeast cells dramatically reduced ADH2 derepression . These results indicate that ADR1 physically associates with TFIID and that its ability to activate transcription requires an intact TFIID complex.

Cell, 1998 Sep 4, 94(5), 679 - 89
Natural variation in a neuropeptide Y receptor homolog modifies social behavior and food response in C . elegans; de Bono M et al.; Natural isolates of C . elegans exhibit either solitary or social feeding behavior . Solitary foragers move slowly on a bacterial lawn and disperse across it, while social foragers move rapidly on bacteria and aggregate together . A loss-of-function mutation in the npr-1 gene, which encodes a predicted G protein-coupled receptor similar to neuropeptide Y receptors, causes a solitary strain to take on social behavior . Two isoforms of NPR-1 that differ at a single residue occur in the wild . One isoform, NPR-1 215F, is found exclusively in social strains, while the other isoform, NPR-1 215V, is found exclusively in solitary strains . An NPR-1 215V transgene can induce solitary feeding behavior in a wild social strain . Thus, isoforms of a putative neuropeptide receptor generate natural variation in C . elegans feeding behavior.

Hum Gene Ther, 1998 Sep 1, 9(13), 1863 - 73
A system for shuttling 200-kb BAC/PAC clones into human cells: stable extrachromosomal persistence and long-term ectopic gene activation; Westphal EM et al.; A novel shuttle vector, pBH140, has been constructed that allows stable maintenance of large genomic inserts as human artificial episomal chromosomes (HAECs) in mammalian cells . The vector, essentially a hybrid BAC-HAEC, contains an F-based replication system as in a bacterial artificial chromosome (BAC) and the Epstein-Barr virus (EBV) latent origin of replication system, oriP, for replication in human cells . A 185-kb DNA insert containing the entire human beta-globin locus, including its locus control region (LCR), was retrofitted into this vector . The resulting beta-globin BAC-HAEC clone, p148BH, was transfected into human cells and analyzed for episomal maintenance and expression of the beta-globin gene . FISH revealed an association of the vector with different human chromosomes but no integration . The beta-globin BAC-HAECs were present at an average copy number of 11-15 per nucleus in the stably transformed human cells . After 1 year of continuous in vitro cultivation, the HAECs persisted as structurally intact 200-kb episomes . While no beta-globin transcription could be detected in the parental D98/Raji cells, correctly spliced RT-PCR products were produced at significant levels in long-term cultures of the BAC-HAEC-transduced cells . The wide availability of BAC and PAC libraries, the ease in manipulating cloned DNA in bacteria, and the episomal stability of the pBH140 vector make this system ideal for studies on gene expression and other genomic functions in human cells . The potential significance of large, functionally active episomes for gene therapy is discussed.

J Pediatr, 1998 Sep, 133(3), 390 - 4
Polymerase chain reaction-based detection of rhinovirus, respiratory syncytial virus, and coronavirus in otitis media with effusion; Pitkaranta A et al.; OBJECTIVES: To study the association of human rhinovirus (HRV), respiratory syncytial virus (RSV), and human coronavirus infections in children aged 6 months to 12 years with otitis media with effusion (OME) . To determine how long HRV RNA can be detected after HRV infection . METHODS: Middle ear effusion (MEE) samples collected at the time of tympanostomy tube placement from 100 children with OME were examined . Viral RNA was detected by reverse-transcriptase polymerase chain reaction . For HRV the results were compared with virus isolation in cell culture . In vitro studies of the persistence of HRV infectivity and RNA were conducted by combining approximately 10(5) median cell culture infectious doses of HRV with pooled MEE at 37 degrees C and assaying serial samples for 12 weeks . RESULTS: Virus RNA was detected in 30 children . HRV was detected by reverse-transcriptase polymerase chain reaction in 19 children with OME and by virus isolation in 5 children . RSV RNA was found in 8 and HCV in 3 children with OME . No dual viral infection was found . Bacterial pathogens were isolated from 35 MEE samples and were associated with viral RNA in 11 cases, most often with HRV (9 cases) . Under in vitro conditions, HRV culture positivity declined rapidly (<2 days), but RNA was detectable for up to 8 weeks . CONCLUSIONS: These results suggest that virus infection, particularly HRV infection, either alone or concurrent with bacteria, is present in a larger percentage of children with OME than previously suspected . It remains to be determined how often the presence of viral RNA in MEE represents persistent RNA, ongoing viral replication, or recurrent infection.

FEBS Lett, 1998 Aug 28, 434(1-2), 209 - 14
Sodium butyrate suppresses apoptosis in human Burkitt lymphomas and murine plasmacytomas bearing c-myc translocations; Alexandrov I et al.; We report that sodium butyrate, a natural product of fiber degradation by colonic bacteria, markedly suppresses c-Myc-mediated apoptosis induced in murine plasmacytomas and human Burkitt lymphomas by growth factor deprivation, but not in cell lines devoid of c-myc translocations . Attenuation of cell death is associated with downregulation of the rearranged c-myc and activation of pRb via its dephosphorylation . We suggest that in vivo sodium butyrate may play an important role in plasmacytomagenesis by supporting the survival of cells with c-myc translocations, which otherwise would be eliminated by the lack of growth factors.

Dev Biol Stand, 1998, 93, 119 - 23
Experience with the Vero cell line; Montagnon BJ et al.; The Vero cell line has been managed with the Cell Bank system to produce at the 142nd passage IPV, OPV and rabies vaccines since 1982 by Pasteur Merieux Serums & Vaccins (PMsv) . The safety of the cell line was regularly validated at the Working Cell Bank (WCB) level according to the WHO and European Pharmacopoeia requirements for absence of bacteria, fungi, mycoplasma and viruses . A special emphasis was devoted to research on the absence of simian viruses (SV40, SIV, Retro-D virus and simian CMV) . All these specific researches were negative . At a low level of passage, the Vero cells are not tumorigenic.Vaccines have been prepared in low passage level Vero cells and together with the excellent downstream purification have resulted in excellent safety as attested by pharmacovigilance of more than 100 million doses of IPV during 12 years, more than 20 million doses of rabies vaccine during 10 years and more than 1 billion of OPV during eight years.

Proc Natl Acad Sci U S A, 1998 Sep 15, 95(19), 11295 - 300
Genetic code origins: tRNAs older than their synthetases?
Ribas de Pouplana L, Turner RJ, Steer BA, Schimmel P.
We present a phylogenetic analysis to determine whether a given tRNA molecule was established in evolution before its cognate aminoacyl-tRNA synthetase . The earlier appearance of tRNA versus their metabolically related enzymes is a prediction of the RNA world theory, but the available synthetase and tRNA sequences previously had not allowed a formal comparison of their relative time of appearance . Using data recently obtained from the emerging genome projects, our analysis points to the extant forms of lysyl-tRNA synthetase being preceded in evolution by the establishment of the identity of lysine tRNA.

Proc Natl Acad Sci U S A, 1998 Sep 15, 95(19), 11122 - 7
A novel yeast protein influencing the response of RNA polymerase II to transcriptional activators; Emili A et al.; A sensitive in vitro crosslinking technique using a photoactive derivative of the chimeric activator LexA-E2F-1 was used to identify yeast proteins that might influence the response of RNA polymerase II to transcriptional activators . We found that a novel yeast protein, Xtc1p, could be covalently crosslinked to the activation domain of LexA-E2F-1 when this derivatized activator was bound to DNA upstream of an activator-responsive RNA polymerase II promoter . Because affinity chromatography experiments showed that Xtc1p also bound directly and specifically to the activation domains of E2F-1, the viral activator VP16, and the yeast activator Gal4p and copurified with the RNA polymerase II holoenzyme complex, Xtc1p may modulate the response of RNA polymerase II to multiple activators . Consistent with this notion, yeast strains deleted for the XTC1 gene exhibited pleiotropic growth defects, including temperature sensitivity, galactose auxotrophy, and a heightened sensitivity to activator overexpression, as well as an altered response to transcriptional activators in vivo.

Antimicrob Agents Chemother, 1998 Sep, 42(9), 2290 - 4
In vitro inactivation of Chlamydia trachomatis by fatty acids and monoglycerides; Bergsson G et al.; The antichlamydial effects of several fatty acids and monoglycerides were studied by incubating Chlamydia trachomatis bacteria with equal volumes of lipid solutions for 10 min and measuring the reduction in infectivity titer compared with that in a control solution without lipid . Caprylic acid (8:0), monocaprylin (8:0), monolaurin (12:0), myristic acid (14:0), palmitoleic acid (16:1), monopalmitolein (16:1), oleic acid (18:1), and monoolein (18:1) at concentrations of 20 mM (final concentration, 10 mM) had negligible effects on C . trachomatis . In contrast, lauric acid (12:0), capric acid (10:0), and monocaprin (10:0) caused a greater than 10,000-fold (>4-log10) reduction in the infectivity titer . When the fatty acids and monoglycerides were further compared at lower concentrations and with shorter exposure times, lauric acid was more active than capric acid and monocaprin was the most active, causing a greater than 100, 000-fold (>5-log10) inactivation of C . trachomatis at a concentration of 5 mM for 5 min . The high levels of activity of capric and lauric acids and particularly that of monocaprin are notable and suggest that these lipids have specific antichlamydial effects . The mode of action of monocaprin was further studied by removal of the lipid by centrifugation before inoculation of Chlamydia onto host cells and by electron microscopy . The results indicate that the bacteria are killed by the lipid, possibly by disrupting the membrane(s) of the elementary bodies . A 50% effective concentration of 30 microgram/ml was found by incubation of Chlamydia with monocaprin for 2 h . The rapid inactivation of large numbers of C . trachomatis organisms by monocaprin suggests that it may be useful as a microbicidal agent for the prevention of the sexual transmission of C . trachomatis.

J Periodontol, 1998 Aug, 69(8), 951 - 4
Current understanding of the role of microscopic monitoring, baking soda, and hydrogen peroxide in the treatment of periodontal disease . Committee on Research, Science and Therapy . The American Academy of Periodontology; The discovery of human granulocytotropic ehrlichiosis; Department of Family Medicine, University of Minnesota, Duluth, USAHuman granulocytotropic ehrlichiosis (HGE) is a tick-borne, acute, nonspecific febrile illness that was first described in 1994 . At this writing more than 300 cases have been recognized in areas where the presumed tick vector Ixodes scapularis occurs endemically . Ehrlichiosis is a nonspecific influenza-like illness, and associated laboratory alterations are variable . Characteristic morulae (clusters of bacteria in leukocyte cytoplasm) can frequently be found in the cytoplasm of circulating neutrophils after careful inspection of the peripheral blood smear . The diagnosis is confirmed by demonstrating seroconversion to the HGE agent, positive polymerase chain reaction, or growth of the HGE agent in tissue culture . Doxycycline provides rapid and effective treatment.

Methods, 1998 Jul, 15(3), 233 - 42
Production, purification, and characterization of recombinant 2', 5'-oligoadenylate synthetases; Sarkar SN et al.; 2',5'-Oligoadenylate {2-5(A)} synthetases are a family of interferon-induced enzymes that polymerize ATP into 2'-5'-linked oligoadenylates in the presence of double-stranded RNA (dsRNA), their cofactor . The 2-5(A) molecules, in turn, activate the latent ribonuclease RNase L by promoting its dimerization . The 2-5(A) synthetase pathway has been implicated in interferon's antiviral and anticellular activities . In addition to their interesting cellular properties, these enzymes are also enzymologically interesting because they are the only known template and primer independent nucleotide (DNA or RNA)polymerases that synthesize 2'-5'-linked oligonucleotides . Moreover, their mode of activation by dsRNA remains unknown . In the past, biochemical and structure-function studies have been hampered by the lack of a convenient system for expressing recombinant 2-5(A) synthetases . These proteins are toxic to mammalian cells, probably because of RNase L activation, and proteins produced in bacteria do not have full enzymatic activity . To circumvent these problems, we have developed a baculovirus-insect cell system for high-yield expression of the small and medium isozymes . Here, methods are described for the production, purification, and characterization of the mouse small (9-2) (S . K . Ghosh, J . Kusari, S . K . Bandyopadhyay, H . Samanta, R . Kumar, and G . C . Sen, 1991, J . Biol . Chem . 266, 15293-15299) and human medium (P69) (I . Marie and A . G . Hovanessian, 1992, J . Biol . Chem . 267, 9933-9939) 2-5(A) synthetase isozymes and their mutants using the insect cell system . We also report methods for studying 2-5(A) synthetase-dsRNA interactions and protein-protein interactions among the subunits of the two isozymes .

J Theor Biol, 1998 May 21, 192(2), 213 - 218
Dynamics of Cytoplasmic Incompatability with Multiple Wolbachia Infections; Frank SA; Wolbachia infections occur in many arthropods . These matrilineally inherited bacteria cause cytoplasmic incompatibility, in which a cross produces no offspring when between an infected male and an uninfected female . Some populations harbour multiple Wolbachia strains . Females fail to produce offspring when crossed to a male with a strain that the female lacks . Prior theoretical work showed that a panmictic population cannot maintain polymorphism for different strains when each female carries only a single strain . A few authors suggested that doubly infected females can stabilize multistrain polymorphism, but conditions for invasion and location of stable equilibrium were not analysed in detail . For two strains, I describe the conditions under which a multiply infected class can spread . Spread of the doubly infected type stabilizes polymorphism of the singly infected classes . This analysis also suggests an interesting extension to higher multiplicity of infection . For an arbitrary number of strains, N, a panmictic population cannot maintain different classes with N-1 infections unless the class with N infections is also present . This pyramid of polymorphism may explain the puzzling diversity of incompatibility types observed in some Culex mosquitos . Multiple infection also has interesting consequences for the dynamics of spatial variation and reproductive isolation.

J Anim Sci, 1998 Aug, 76(8), 2190 - 6
The role of pH in regulating ruminal methane and ammonia production; Lana RP et al.; When steers (n = 4) were fed increasing amounts of concentrate (0, 45, or 90% of DM) and decreasing amounts of forage, the VFA concentration increased (P < .001) and ruminal pH, acetate:propionate ratio, and dissociated ammonia declined (P < .001) . Acetate:propionate ratio and dissociated ammonia were highly correlated (r2 = .82 and .65, respectively) with ruminal pH . In vivo acetate:propionate ratio was highly correlated (r2 = .78) with the capacity of the bacteria to produce methane from H2 and CO2 in vitro, and in vivo pH-dissociated ammonia was correlated (r2 = .59) with the capacity of the bacteria to produce ammonia from protein hydrolysate . The role of pH in regulating methane and ammonia production was supported by the effect of pH in vitro . When bacteria from cattle fed concentrate or forage were incubated at pH values from 6.5 to 5.7, methane production decreased (P < .001) from 48 to 7 nmol x mg protein(-1) x min(-1) and from 14 to 2 nmol x mg protein(-1) x min(-1), respectively . The reduction in in vitro pH (6.5 to 5.7) also decreased (P < .001) the rates of ammonia production, but only if the bacteria were obtained from cattle fed forage (28 to 15 nmol x mg protein(-1) x min(-1)) . Bacteria from cattle fed 90% concentrate had similar (P > .05) rates of ammonia production at pH 6.5 to 5.7 (approximately 12 nmol x mg protein(-1) x min(-1)) . These results indicated that ruminal pH affected ruminal methane production, acetate:propionate ratio, deamination, and ammonia concentration.

J Biol Chem, 1998 Sep 18, 273(38), 24654 - 9
Dictyostelium TRFA homologous to yeast Ssn6 is required for normal growth and early development; Saito J et al.; The TPR (tetratricopeptide repeat) family became widespread during evolution, having been found from bacteria to mammals . By means of restriction enzyme-mediated integration, we have identified a Dictyostelium gene (trfA) highly homologous to a Saccharomyces cerevisiae gene encoding a TPR protein, Ssn6 (Cyc8), which functions as a global transcriptional repressor for diverse genes . The deduced amino acid sequence of the Dictyostelium gene product, TRFA, contains 10 consecutive TPR units as well as Gln repeats, Asn repeats, and a region rich in Glu, Lys, Ser, and Thr . The sequences of some of the 10 TPR units in TRFA are more than 70% identical to the corresponding units in Ssn6 . The trfA- cells produced smooth plaques on a bacterial lawn and failed to aggregate normally when starved on a plain agar plate . Individual trfA- cells also failed to correctly respond to cAMP, although the adenylyl cyclase of trfA- cells was expressed upon starvation and activated by stimulation with cAMP as in the wild-type cells . When cultured in a rich medium in suspension, they grew more slowly and stopped growing at a lower density than the wild-type cells . Furthermore, they divided into cells of various sizes and tended to be much smaller than the wild-type cells . These pleiotropic defects of the trfA- cells suggest the possibility that Dictyostelium TRFA may regulate the transcription of diverse genes required for normal growth and early development.

J Bacteriol, 1998 Sep, 180(18), 4946 - 9
Transcriptional analysis and mutation of a dnaA-like gene in Synechocystis sp . strain PCC 6803; Richter S et al.; Transcription of the dnaA gene of the cyanobacterium Synechocystis sp . strain PCC 6803 is light dependent and yields a monocistronic mRNA, as determined by Northern analysis . Surprisingly, mutants with inactivated dnaA were viable . In batch cultures under standard conditions, the mutants grew like the wild type and did not show an aberrant phenotype . We conclude that, unlike the situation in other bacteria, dnaA of Synechocystis sp . cannot have an essential function, such as initiation of DNA replication.

J Bacteriol, 1998 Sep, 180(18), 4856 - 64
Oxidative stress response and characterization of the oxyR-ahpC and furA-katG loci in Mycobacterium marinum; Pagan-Ramos E et al.; Oxidative stress response in pathogenic mycobacteria is believed to be of significance for host-pathogen interactions at various stages of infection . It also plays a role in determining the intrinsic susceptibility to isoniazid in mycobacterial species . In this work, we characterized the oxyR-ahpC and furA-katG loci in the nontuberculous pathogen Mycobacterium marinum . In contrast to Mycobacterium smegmatis and like Mycobacterium tuberculosis and Mycobacterium leprae, M . marinum was shown to possess a closely linked and divergently oriented equivalents of the regulator of peroxide stress response oxyR and its subordinate gene ahpC, encoding a homolog of alkyl hydroperoxide reductase . Purified mycobacterial OxyR was found to bind to the oxyR-ahpC promoter region from M . marinum and additional mycobacterial species . Mobility shift DNA binding analyses using OxyR binding sites from several mycobacteria and a panel of in vitro-generated mutants validated the proposed consensus mycobacterial recognition sequence . M . marinum AhpC levels detected by immunoblotting, were increased upon treatment with H2O2, in keeping with the presence of a functional OxyR and its binding site within the promoter region of ahpC . In contrast, OxyR did not bind to the sequences upstream of the katG structural gene, and katG expression did not follow the pattern seen with ahpC . Instead, a new open reading frame encoding a homolog of the ferric uptake regulator Fur was identified immediately upstream of katG in M . marinum . The furA-katG linkage and arrangement are ubiquitous in mycobacteria, suggesting the presence of additional regulators of oxidative stress response and potentially explaining the observed differences in ahpC and katG expression . Collectively, these findings broaden our understanding of oxidative stress response in mycobacteria . They also suggest that M . marinum will be useful as a model system for studying the role of oxidative stress response in mycobacterial physiology, intracellular survival, and other host-pathogen interactions associated with mycobacterial diseases.

J Bacteriol, 1998 Sep, 180(18), 4850 - 5
Transformation of the Lyme disease spirochete Borrelia burgdorferi with heterologous DNA; Stevenson B et al.; Studies of the spirochete Borrelia burgdorferi have been hindered by the scarcity of genetic tools that can be used in these bacteria . For the first time, a method has been developed by which heterologous DNA (DNA without a naturally occurring B . burgdorferi homolog) can be introduced into and persistently maintained by B . burgdorferi . This technique uses integration of circular DNA into the bacterial genome via a single-crossover event . The ability to transform B . burgdorferi with heterologous DNA will now permit a wide range of experiments on the biology of these bacteria and their involvement in the many facets of Lyme disease.

Arch Microbiol, 1998 Oct, 170(4), 227 - 35
Nucleoids and coated vesicles of "Epulopiscium" spp
Robinow C, Angert ER.
We describe here aspects of the anatomy of two "Epulopiscium" morphotypes, unusually large bacteria that are not yet cultured and that reproduce by the internal generation of two or more vegetative daughter cells . Two morphotypes, A and B, which are enteric symbionts of several species of herbivorous surgeonfish (Acanthuridae), were collected around the Great Barrier Reef of Australia, preserved there, and later stained for light microscopy . Some samples were examined by electron microscopy . In both morphotypes, countless discrete nucleoplasms or nucleoids were found to occupy a single shallow layer just beneath the surface all around these organisms . At each end of the morphotype B cells, a membrane-bound compartment containing dense cords of chromatin was observed . When these were found at each end of growing daughter cells, no polar compartments were then found in their mother organism . Electron micrographs of sections of morphotype A symbionts show that their outermost region is composed of tightly packed coated vesicles, each surrounded by a thin, dense, spacious capsule . Near the surface of type A organisms the remains of broken vesicles, broken capsules, and a finely fibrous matrix fuse to form a fabric that serves as the cell wall . Morphotype B organisms, however, were observed to have a distinct, morphologically continuous outer wall.

Int J Syst Bacteriol, 1998 Apr, 48 Pt 2, 503 - 10
Characterization of Actinomyces turicensis and Actinomyces radingae strains from human clinical samples; Vandamme P et al.; Whole-organism protein electrophoresis was used to compare and group unidentified coryneform bacteria resembling Gardnerella vaginalis and various Actinomyces and Arcanobacterium species . The obtained clusters of strains were further characterized by whole-cell fatty acid analysis and a variety of biochemical tests . Species-specific oligonucleotide probes based on 16S rRNA gene sequences were designed . The results demonstrate that the majority of the isolates belonged to Actinomyces turicensis; the other strains belonged to Actinomyces radingae . The descriptions of both species are emended.

Biochemistry, 1998 Sep 8, 37(36), 12611 - 23
Catalytic and biophysical properties of a nitrogenase Apo-MoFe protein produced by a nifB-deletion mutant of Azotobacter vinelandii; Christiansen J et al.; A Zn-immobilized metal-affinity chromatography technique was used to purify a poly-histidine-tagged, FeMo-cofactorless MoFe protein (apo-MoFe protein) from a nifB-deletion mutant of Azotobacter vinelandii . Apo-MoFe protein prepared in this way was obtained in sufficient concentrations for detailed catalytic, kinetic, and spectroscopic analyses . Metal analysis and electron paramagnetic resonance spectroscopy (EPR) were used to show that the apo-MoFe protein does not contain FeMo-cofactor . The EPR of the as-isolated apo-MoFe protein is featureless except for a minor S = 1/2 signal probably arising from the presence of either a damaged P cluster or a P cluster precursor . The apo-MoFe protein has an alpha2beta2 subunit composition and can be activated to 80% of the theoretical MoFe protein value by the addition of isolated FeMo-cofactor . Oxidation of the as-isolated apo-MoFe protein by indigodisulfonate was used to elicit the parallel mode EPR signal indicative of the two-electron oxidized form of the P cluster (P2+) . The midpoint potential of the PN/P2+ redox couple for the apo-MoFe protein was shown to be shifted by -63 mV when compared to the same redox couple for the intact MoFe protein . Although the apo-MoFe protein is not able to catalyze the reduction of substrates under turnover conditions, it does support the hydrolysis of MgATP at 60% of the rate supported by the MoFe protein when incubated in the presence of Fe protein . The ability of the apo-MoFe protein to specifically interact with the Fe protein was also shown by stopped-flow techniques and by formation of an apo-MoFe protein-Fe protein complex . Finally, the two-electron oxidized form of the apo-MoFe protein could be reduced to the one-electron oxidized form (P1+) in a reaction that required Fe protein and MgATP . These results are interpreted to indicate that the apo-MoFe protein produced in a nifB-deficient genetic backround contains intact P clusters and P cluster polypeptide environments . Small changes in the electronic properties of P clusters contained within the apo-MoFe protein are most likely caused by slight perturbations in their polypeptide environments.

Biochemistry, 1998 Sep 8, 37(36), 12452 - 7
Imidazole is a sensitive probe of steric hindrance in the distal pockets of oxygen-binding heme proteins; Mansy SS et al.; The FixL heme-based sensor, despite its low affinity for oxygen, is much more reactive than myoglobin toward the large polar ligand imidazole . To determine which features of a myoglobin heme pocket favor binding of imidazole, we have measured binding of this ligand to the FixL heme domain, elephant myoglobin, wild-type sperm whale myoglobin, and sperm whale myoglobins having alanine, valine, threonine, glutamine, leucine, phenylalanine, or tryptophan substitutions of the distal (E7) histidine residue . Except for histidine, the association rate constants dropped more than 3000-fold as the volume of the E7 side chain, at position 64, was expanded from alanine (10(6) M-1 s-1) to phenylalanine (10(3) M-1 s-1) . There was inhibition of imidazole binding due to displacement of coordinated water from H64 and H64Q sperm whale myoglobins, where the E7 side chain hydrogen bonds directly to the bound ligand . The imidazole dissociation rate constants varied less dramatically and less consistently with any single factor, though they were measurably decreased by hydrogen bonding to an E7 glutamine or histidine . On the whole, the results for the sperm whale myoglobin E7 substitutions show that the rate constants for imidazole binding are useful and sensitive indicators of steric hindrance and polar interactions in the distal pockets of myoglobins . The combined effects of the glutamine 64 and phenylalanine 29 in elephant myoglobin largely account for its increased imidazole association and dissociation rate constants, respectively, compared to those of sperm whale myoglobin . An unhindered distal pocket not competent to stabilize positive poles is indicated by the large imidazole association (>/=10(4) M-1 s-1) and dissociation (>/=50 s-1) rate constants, parameters that are characteristic of FixL.

Retina, 1998, 18(4), 348 - 55
Bartonella serology for patients with intraocular inflammatory disease; Rothova A et al.; PURPOSE: To determine the role of Bartonella henselae in intraocular inflammatory disease and identify its clinical features . METHODS: We retrospectively determined the serum immunoglobulin (Ig)G and IgM antibodies against B . henselae and Bartonella quintana by enzyme immunoassays in stored sera of 138 consecutive newly referred patients with uveitis who, during the acute stage of their ocular disease, underwent a standardized screening protocol to determine the cause of uveitis . RESULTS: For the entire series, the frequency of high positive levels of IgG (above 1:900) or IgM (above 1:300) antibody against B . henselae was 6% (8/138) and 3% (4/138), respectively . Except for cross-reactions between B . henselae and B . quintana, we did not find additional evidence for cross-reactions among the various bacteria tested (Coxiella burnetii and Chlamydia pneumoniae) . All patients with proven infectious uveitis (n = 21) and those with established uveitic entities (n = 37) had negative B . henselae serology . High positive IgG levels were observed in 9% of patients (5/54) with unknown cause of uveitis, in two subjects with human leukocyte antigen (HLA)-B27 positive uveitis, and in one with sarcoidosis . Five patients with uveitis of unknown origin and highly elevated IgG levels against B . henselae exhibited clinical features characterized by papillitis with surrounding retinal focal lesions or edema . CONCLUSIONS: The serologic and clinical data indicate that uveitis in seropositive cases may be caused by B . henselae . We do not recommend including testing for B . henselae in initial screening of patients with uveitis, but consider it worthwhile for those with papillitis and screening results within normal limits.

Fogorv Sz, 1998 Aug-Sep, 91(8-9), 269 - 74
{Pathogenesis of apical periodontitis and its effects on the body}; Marton I et al.; During the last 25 years there have been major advances in understanding the etiology, pathogenesis and maintenance of inflammatory processes taking place in the periapical space . Polymicrobial infection of the pulp chamber is of primary importance in initiating periapical inflammation . Egress of bacteria and their antigenes stimulate the immune system to form a granulation tissue around the apical area . Local immune response eliminates excess number of invading organisms . However, in parallel with protective reactions, local activity of immunocompetent cells and their soluble products also contribute to tissue damage, bone resorption and perpetuation of inflammation . Present data indicate that interaction of T-lymphocytes and macrophages is crucial in this process.

Teratog Carcinog Mutagen, 1998, 18(3), 131 - 40
Induction of DNA adducts in vivo in rat lung cells by fume condensates of roofing asphalt; Qian HW et al.; Many workers in the highway construction and roofing industries are potentially exposed to asphalt fumes . However, little is known regarding the carcinogenic hazards of these fumes to the exposed workers . Previous studies have shown that condensates of asphalt fumes are weakly mutagenic to bacteria and are capable of inducing micronucleus formation in cultured mammalian cells . In this study, the induction of DNA adducts in vivo in lung and white blood cells (WBCs) of rats by fume condensates of type I and type III roofing asphalts was investigated using 32P-postlabeling analysis . Male CD rats (3/group) received 3 intratracheal instillations of fume condensates in a 24-h period . DNA from both lung cells and WBCs were isolated and used to detect DNA adducts . Condensates of both roofing asphalt fumes caused DNA adduct formation in rat lung cells in a similar dose-related manner . Under the conditions studied, however, neither type I nor type III fume condensate induced DNA adducts in WBCs . These results indicate that 1) condensates of fumes from both type I and type III have similar genotoxic activity, 2) chemicals in the condensates of roofing asphalt fumes can covalently bind to the DNA of rat lung cells, and 3) WBCs may not be a suitable surrogate for lung cells in DNA adduct studies of workers exposed to roofing asphalt fumes.

J Infect Dis, 1998 Sep, 178(3), 896 - 9
Clarithromycin significantly improves interleukin-12-mediated anti-Mycobacterium avium activity and abolishes toxicity in mice; Bermudez LE et al.; Treatment of experimental murine Mycobacterium avium (MAC) infection with interleukin-12 (IL-12) significantly decreased MAC organisms in tissue but resulted in toxicity . Because IL-12-related toxicity was seen only in infected mice, IL-12 was combined with clarithromycin in an attempt to decrease bacterial burden . Clarithromycin (200 mg/kg/day) was administered alone to M . avium-infected mice for 1 week, and from week 2, IL-12 (20 microg/kg twice per week) was added to the regimen for 4 weeks . Treatment with IL-12 resulted in 60% mortality, compared with 40% mortality in untreated control mice and 20% when IL-12 was given with clarithromycin (P < .05) . Clarithromycin plus IL-12 resulted in increased activity compared with either clarithromycin or IL-12 alone in reducing the number of bacteria in spleen and blood . Although potentially toxic, IL-12 is an effective immunotherapy for MAC infection, and combination with clarithromycin reduces IL-12 toxicity.

Physiol Res, 1997, 46(3), 193 - 7
Effects of immunomodulators on postirradiation recovery in the thymus; Mackova NO et al.; The effect of immunomodulatory agents on reparation processes in the thymus was studied in mice injured by a single sublethal or lethal dose of ionizing radiation ranging between 6.5-9.5 Gy . Reparation of thymus weight was not influenced by pretreatment with immunomodulators . Furthermore, the morphological picture did not exhibit appreciable differences between non-protected and protected groups, except for greater proliferation of fibroblasts and macrophages in protected animals.

Pediatr Pulmonol, 1998 Aug, 26(2), 135 - 7
Chronic anaerobic pneumonitis in a seven-year-old girl; Agarwal AK et al.; A 7-year-old girl was referred for evaluation of chronic pulmonary disease associated with nasal symptoms of 4 years duration for which she had received frequent courses of antibiotics . Serial chest roentgenograms over a period of 2 years revealed a nonhomogeneous opacity in the right lower lung zone for which she had received 18 months of antituberculous therapy without relief . Evaluation of the patient led to the diagnosis of chronic anaerobic pneumonitis, a rare clinical entity in children . In addition, the patient also had bronchial asthma and chronic rhinitis . Therapy with oral phenoxymethylpenicillin and metronidazole for 6 weeks along with appropriate antiasthma medications abolished her symptoms and resulted in roentgenologic clearance.

J Biol Chem, 1998 Sep 11, 273(37), 23629 - 32
Expression cloning and characterization of a transporter for large neutral amino acids activated by the heavy chain of 4F2 antigen (CD98); Kanai Y et al.; A cDNA was isolated from rat C6 glioma cells by expression cloning which encodes a novel Na+-independent neutral amino acid transporter designated LAT1 . For functional expression in Xenopus oocytes, LAT1 required the heavy chain of 4F2 cell surface antigen (CD98), a type II membrane glycoprotein . When co-expressed with 4F2 heavy chain, LAT1 transported neutral amino acids with branched or aromatic side chains and did not accept basic amino acids or acidic amino acids . The transport via LAT1 was Na+-independent and sensitive to a system L-specific inhibitor 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid . These functional properties correspond to those of the classically characterized amino acid transport system L, a major nutrient transporter . In in vitro translation, LAT1 was shown to be a nonglycosylated membrane protein consistent with the property of 4F2 light chain, suggesting LAT1 is at least one of the proteins formerly referred to as 4F2 light chain . LAT1 exhibits relatively low but significant amino acid sequence similarity to mammalian cationic amino acid transporters and amino acid permeases of bacteria and yeasts, indicating LAT1 is a new member of the APC superfamily . Because of highly regulated nature and high level of expression in tumor cell lines, LAT1 is thought to be up-regulated to support the high protein synthesis for cell growth and cell activation . The cloning of LAT1 is expected to facilitate the research on the protein-protein interaction in the transporter field and to provide a clue to the search for still unidentified transporters.

Acta Otolaryngol, 1998 Jul, 118(4), 563 - 6
Gammadelta T cell receptor repertoire in middle ear effusions in children; Takeuchi K et al.; In order to elucidate the immune response in otitis media with effusion, polymerase chain reaction was employed to examine gammadelta T cell receptor repertoire in the middle ear effusions of patients with otitis media with effusion . RNAs were extracted from 13 middle ear effusions of 10 children with otitis media with effusion . Vgamma2 was the most frequently used Vgamma gene . As for Vdelta gene usage, Vdelta2 amplification gave the strongest signal in 10 out of 13 samples . The results suggest that gammadelta T cells bearing Vgamma2/Vdelta2 T cell receptors accumulate in the middle ear effusions in children, and that these T cells may respond to certain bacteria or bacterial products in the middle ear.

AJNR Am J Neuroradiol, 1998 Aug, 19(7), 1294 - 5
Cat-scratch disease with an extraaxial mass; Roebuck DJ; CT and MR imaging of the brain and gallium-67 scintigraphy showed an enhancing, gallium-avid mass in the left middle cranial fossa of a 10-year-old girl . Craniotomy revealed an inflammatory mass related to the left trigeminal nerve . The lesion contained rodlike bacteria, and serologic tests were positive for cat-scratch disease . Neurologic involvement in cat-scratch disease is uncommon, and the presence of organisms in neural tissue has not been reported.

J Endourol, 1998 Aug, 12(4), 325 - 33
Organ retrieval systems for endoscopic nephrectomy: a comparative study; Rassweiler J et al.; Laparoscopic or retroperitoneoscopic interventions such as nephrectomy or tumor nephrectomy call for the removal of large quantities of tissue, which can no longer be extracted via the relatively confined lumen of a cannula . For this purpose, a variety of organ retrieval systems have been designed and are commercially available with the aim of safe tissue retrieval . This paper summarizes the results of an experimental and clinical comparison of the most important organ entrapment systems suitable for endoscopic nephrectomy . The LapSacs was the first organ bag especially designed for laparoscopic nephrectomy . Despite various new modifications of this entrapment system, it still represents one of the best alternatives and has been used worldwide with success . However, because of its simplicity, it requires a certain laparoscopic expertise and involves a learning curve . Newly developed retrieval systems (i.e., LapBag, Extraction Bag, Endo-Catch) offer some advantages regarding the handling of the bag, which may be particularly useful during retroperitoneoscopic nephrectomy with a restricted working space . Retrieval systems (i.e., Endobag, Endopouch) with low resistance to tearing forces or permeability to tumor cells or bacteria (i.e., Espiner Bag) cannot be recommended for endoscopic nephrectomy.

Mutat Res, 1998 Aug 7, 416(1-2), 115 - 24
Studies on the genotoxicity of the mammalian lignans enterolactone and enterodiol and their metabolic precursors at various endpoints in vitro; Kulling SE et al.; The mammalian lignans enterolactone (ENL) and enterodiol (END) are formed by intestinal bacteria from the plant lignans matairesinol (MAT) and secoisolariciersinol (SEC), respectively, which are ingested with different types of food . ENL and END are weak estrogens . According to epidemiological and biochemical studies, lignans may act as anticarcinogens, but little is known about their genotoxic potential . We have therefore investigated the effects of ENL, END, MAT and SEC on cell-free microtubule assembly and at the following genetic endpoints in cultured male Chinese hamster V79 cells: disruption of the cytoplasmic microtubule complex, induction of mitotic arrest, induction of micronuclei and their characterization by CREST staining, and mutagenicity at the HPRT gene locus . The lignans were tested at concentrations of 200 microM in the cell-free system and 100 microM in cultured cells, which represents the limit of solubility in each assay . The established aneuploidogen diethylstilbestrol and the clastogen 4-nitroquinoline-N-oxide were used as positive reference compounds . As none of the four lignans had any activity at the endpoints studied, we conclude that ENL, END, MAT and SEC are devoid of aneuploidogenic and clastogenic potential under the experimental conditions used in this study.

Genetics, 1998 Sep, 150(1), 227 - 37
Wolbachia transfer from Drosophila melanogaster into D . simulans: Host effect and cytoplasmic incompatibility relationships; Poinsot D et al.; Wolbachia are maternally transmitted endocellular bacteria causing a reproductive incompatibility called cytoplasmic incompatibility (CI) in several arthropod species, including Drosophila . CI results in embryonic mortality in incompatible crosses . The only bacterial strain known to infect Drosophila melanogaster (wDm) was transferred from a D . melanogaster isofemale line into uninfected D . simulans isofemale lines by embryo microinjections . Males from the resulting transinfected lines induce >98% embryonic mortality when crossed with uninfected D . simulans females . In contrast, males from the donor D . melanogaster line induce only 18-32% CI on average when crossed with uninfected D . melanogaster females . Transinfected D . simulans lines do not differ from the D . melanogaster donor line in the Wolbachia load found in the embryo or in the total bacterial load of young males . However, >80% of cysts are infected by Wolbachia in the testes of young transinfected males, whereas only 8% of cysts are infected in young males from the D . melanogaster donor isofemale line . This difference might be caused by physiological differences between hosts, but it might also involve tissue-specific control of Wolbachia density by D . melanogaster . The wDm-transinfected D . simulans lines are unidirectionally incompatible with strains infected by the non-CI expressor Wolbachia strains wKi, wMau, or wAu, and they are bidirectionally incompatible with strains infected by the CI-expressor Wolbachia strains wHa or wNo . However, wDm-infected males do not induce CI toward females infected by the CI-expressor strain wRi, which is found in D . simulans continental populations, while wRi-infected males induce partial CI toward wDm-infected females . This peculiar asymmetrical pattern could reflect an ongoing divergence between the CI mechanisms of wRi and wDm . It would also confirm other results indicating that the factor responsible for CI induction in males is distinct from the factor responsible for CI rescue in females.

Protein Eng, 1998 Jun, 11(6), 447 - 55
Probing the stabilizing role of C-terminal residues in trimethylamine dehydrogenase; Ertughrul OW et al.; In trimethylamine dehydrogenase, a homodimeric iron-sulfur flavoprotein, the C-terminal 17 residues of each subunit (residues 713-729) embrace residues on the other subunit . The role of this unusual mode of interaction at the subunit interface was probed by isolating three mutant forms of trimethylamine dehydrogenase in which the C-terminus of the enzyme was deleted by five residues {delta(725-729}, 10 residues {delta(720-729)} and 17 residues {delta(713-729)} . The solution properties and conformational states of the three mutant enzymes were investigated using optical, fluorescence and circular dichroism spectroscopies, ANS binding and a novel and conformationally sensitive hydrodynamic method . The data reveal that sequential deletion of the C-terminus of trimethylamine dehydrogenase does not affect significantly dimer stability or the overall structural integrity of the enzyme . However, deletion of the C-terminus severely compromises, but does not abolish, the ability of the enzyme to become covalently coupled with the redox cofactor FMN in the active site, located over 20 A from the C-terminus . Hydrodynamic studies reveal minor conformational changes in the deletion mutants that lead to a more compact enzyme structure . These conformational changes are probably transmitted to the active site via altering the interaction of the C-terminus with the second helix in the beta/alpha barrel of trimethylamine dehydrogenase, leading to poor flavinylation during the folding of the enzyme and assembly with FMN.

Proc Natl Acad Sci U S A, 1998 Sep 1, 95(18), 10728 - 33
An SmtB-like repressor from Synechocystis PCC 6803 regulates a zinc exporter; Thelwell C et al.; ORF slr0798, now designated ziaA, from Synechocystis PCC 6803 encodes a polypeptide with sequence features of heavy metal transporting P-type ATPases . Increased Zn2+ tolerance and reduced 65Zn accumulation was observed in Synechococcus PCC 7942, strain R2-PIM8(smt), containing ziaA and upstream regulatory sequences, compared with control cells . Conversely, reduced Zn2+ tolerance was observed following disruption of ziaA in Synechocystis PCC 6803, and ziaA-mediated restoration of Zn2+ tolerance has subsequently been used as a selectable marker for transformation . Nucleotide sequences upstream of ziaA, fused to a promoterless lacZ gene, conferred Zn2+-dependent beta-galactosidase activity when introduced into R2-PIM8(smt) . The product of ORF sll0792, designated ZiaR, is a Zn2+-responsive repressor of ziaA transcription . Reporter gene constructs lacking ziaR conferred elevated Zn2+-independent expression from the ziaA operator-promoter in R2-PIM8(smt) . Gel retardation assays detected ZiaR-dependent complexes forming with the zia operator-promoter and ZiaR-DNA binding was enhanced by treatment with a metal-chelator in vitro . Two mutants of ZiaR (C71S/C73S and H116R) bound to, and repressed expression from, the ziaA operator-promoter but were unable to sense Zn2+ . Metal coordination to His-imidazole and Cys-thiolate ligands at these residues of ZiaR is thus implicated in Zn2+-perception by Synechocystis PCC 6803.

Plant Cell, 1998 Sep, 10(9), 1523 - 37
PIOX, a new pathogen-induced oxygenase with homology to animal cyclooxygenase; Sanz A et al.; Changes in gene expression induced in tobacco leaves by the harpin HrpN protein elicitor were examined, and a new cDNA, piox (for pathogen-induced oxygenase), with homology to genes encoding cyclooxygenase or prostaglandin endoperoxide synthase (PGHS), was identified . In addition to the amino acid identity determined, the protein encoded by piox is predicted to have a structural core similar to that of ovine PGHS-1 . Moreover, studies of protein functionality demonstrate that the PIOX recombinant protein possesses at least one of the two enzymatic activities of PGHSs, that of catalyzing the oxygenation of polyunsaturated fatty acids . piox transcripts accumulated after protein elicitor treatment or inoculation with bacteria . Expression of piox was induced in tissues responding to inoculation with both incompatible and compatible bacteria, but RNA and protein accumulation differed for both types of interactions . We show that expression of piox is rapidly induced in response to various cellular signals mediating plant responses to pathogen infection and that activation of piox expression is most likely related to the oxidative burst that takes place during the cell death processes examined . Cyclooxygenase catalyzes the first committed step in the formation of prostaglandins and thromboxanes, which are lipid-derived signal molecules that mediate many cellular processes, including the immune response in vertebrates . The finding of tobacco PIOX suggests that more similarities than hitherto expected will be found between the lipid-based responses for plant and animal systems.

Biochemistry, 1998 Sep 1, 37(35), 12058 - 67
Pro region C-terminus:protease active site interactions are critical in catalyzing the folding of alpha-lytic protease; Peters RJ et al.; alpha-Lytic protease is encoded with a large (166 amino acid) N-terminal pro region that is required transiently both in vivo and in vitro for the correct folding of the protease domain {Silen, J . L . , and Agard, D . A . (1989) Nature 341, 462-464; Baker, D., et al . (1992) Nature 356, 263-265} . The pro region also acts as a potent inhibitor of the mature enzyme {Baker, D., et al . (1992) Proteins: Struct.,Funct., Genet . 12, 339-344} . This inhibition is mediated through direct steric occlusion of the active site by the C-terminal residues of the pro region {Sohl, J . L., et al . (1997) Biochemistry 36, 3894-3904} . Through mutagenesis and structure-function analyses we have begun to investigate the mechanism by which the pro region acts as a single turnover catalyst to facilitate folding of the mature protease . Of central interest has been mapping the interface between the pro region and the protease and identifying interactions critical for stabilizing the rate-limiting folding transition state . Progressive C-terminal deletions of the pro region were found to have drastic effects on the rate at which the pro region folds the protease but surprisingly little effect on inhibition of protease activity . The observed kinetic data strongly support a model in which the detailed interactions between the pro region C-terminus and the protease are remarkably similar to those of known substrate/inhibitor complexes . Further, mutation of two protease residues near the active site have significant effects on stabilization of the folding transition state (kcat) or in binding to the folding intermediate (KM) . Our results suggest a model for the alpha-lytic protease pro region-mediated folding reaction that may be generally applicable to other pro region-dependent folding reactions.

Insect Mol Biol, 1998 Nov, 7(4), 393 - 6
Phylogenetic analysis of parthenogenesis-inducing Wolbachia in the genus Aphytis (Hymenoptera: Aphelinidae); Gottlieb Y et al.; Parthenogenesis-inducing intracellular bacteria of the genus Wolbachia are found in a variety of parasitoid wasp genera . The presence of Wolbachia in the uniparental Aphytis species A . lingnanensis Compere, A . diaspidis (Howard), A . chilensis Howard, and A . chrysomphali (Mercet) was tested using primers specific for the ftsZ gene . The symbiont was detected in all of these species . Wolbachia ftsZ genes that were sequenced from the four hosts show a high degree of similarity . Both the PCR with specific primers for group 'A' and phylogenetic analysis place these Wolbachia in group 'A' . The fact that the tested Aphytis species belong to different phylogenetic groups and harbour what seem to be almost identical Wolbachia, lends credence to the horizontal transmission hypothesis.

Int Immunol, 1998 Aug, 10(8), 1111 - 9
Activation of B cells by 1 microm particulate lysozyme or peptides: a Th-dependent pathway requiring CD40-CD40 ligand interaction; Sedlik C et al.; Many antigens encountered by the immune system are included in complex structures such as bacteria or parasites . We previously developed an in vivo model to study the immunogenicity of particulate antigens, based on covalent linkage of proteins or peptides to 1 microm latex particles and showed that these antigens cannot be presented to MHC class II-restricted specific T cells by B cells . However, they induce strong CD4+ T cell responses when injected to mice without adjuvant . The present study demonstrates that four out of the five proteins tested did not stimulate antibody synthesis when linked to 1 microm microparticles, although a strong IgG production was induced by the same proteins administered in soluble form with adjuvant . In contrast, lysozyme and two synthetic peptides containing B and T cell viral epitopes induced strong and long-lasting specific antibody responses when linked to 1 micrometer synthetic beads . The isotypic pattern of antibodies induced by particulate lysozyme was similar to that induced by the soluble protein in alum . Studies using CD4+ T cell-depleted mice revealed that the induction of antibodies by particulate lysozyme strictly required Th cell activity . Moreover, the T-B cell cooperation involved in B cell activation by antigens linked to beads required CD40-CD40 ligand interaction . Thus, these particulate antigens provide a useful tool to study the mechanisms of induction of antibody response against complex bacterial or parasitic antigens . Moreover, they may represent attractive candidates to elaborate efficient new vaccines using short synthetic peptides.

Ann Periodontol, 1998 Jul, 3(1), 251 - 6
Associations between oral conditions and respiratory disease in a national sample survey population; Scannapieco FA et al.; Respiratory infectious diseases such as bacterial pneumonia and bronchitis are common and costly, especially in institutionalized and elderly inpatients . Respiratory infection is thought to rely in part on the aspiration of oropharyngeal flora into the lower respiratory tract and failure of host defense mechanisms to eliminate the contaminating bacteria, which then multiply to cause infection . It has been suggested that dental plaque may act as a reservoir of respiratory pathogens, especially in patients with periodontal disease . However, the impact of poor oral health on oral respiratory pathogen colonization and lung infection is uncertain, especially in ambulatory, non-institutionalized populations . To begin to assess potential associations between respiratory diseases and oral health, data from the National Health and Nutrition Examination Survey I (NHANES I) were analyzed . This database contains information on the general health status of 23,808 individual Of these, 386 individuals reported a suspected respiratory condition that was further assessed by a physician . These subjects were categorized as having a confirmed chronic respiratory disease (chronic bronchitis or emphysema) or an acute respiratory disease (influenza, pneumonia, acute bronchitis) . They were compared to those not having a respiratory disease . Initial non-parametric analysis noted that individuals with a confirmed chronic respiratory disease (n = 41) had significantly greater oral hygiene index scores than subjects without respiratory disease (n = 193; P = 0.0441) . Logistic regression analysis of data from these subjects, which considered age, race, gender, smoking status, and simplified oral hygiene index (OHI), suggested that subjects having the median OHI value were 1.3 times more likely to have a chronic respiratory disease relative to those with and OHI of O . Similarly, subjects with the maximum OHI value were 4.5 times more likely to have a chronic respiratory disease than those with an OHI of O . No evidence was found to support an association between the periodontal index and any respiratory disease . These results suggest OHI to have a residual effect on chronic respiratory disease of both practical and statistical significance.

Nucleic Acids Res, 1998 Sep 15, 26(18), 4205 - 13
Toprim--a conserved catalytic domain in type IA and II topoisomerases, DnaG-type primases, OLD family nucleases and RecR proteins; Aravind L et al.; Iterative profile searches and structural modeling show that bacterial DnaG-type primases, small primase-like proteins from bacteria and archaea, type IA and type II topoisomerases, bacterial and archaeal nucleases of the OLD family and bacterial DNA repair proteins of the RecR/M family contain a common domain, designated Toprim (topoisomerase-primase) domain . The domain consists of approximately 100 amino acids and has two conserved motifs, one of which centers at a conserved glutamate and the other one at two conserved aspartates (DxD) . Examination of the structure of Topo IA and Topo II and modeling of the Toprim domains of the primases reveal a compact beta/alpha fold, with the conserved negatively charged residues juxtaposed, and inserts seen in Topo IA and Topo II . The conserved glutamate may act as a general base in nucleotide polymerization by primases and in strand rejoining by topoisomerases and as a general acid in strand cleavage by topoisomerases and nucleases . The role of this glutamate in catalysis is supported by site-directed mutagenesis data on primases and Topo IA . The DxD motif may coordinate Mg2+that is required for the activity of all Toprim-containing enzymes . The common ancestor of all life forms could encode a prototype Toprim enzyme that might have had both nucleotidyl transferase and polynucleotide cleaving activity.

J Biol Chem, 1998 Sep 4, 273(36), 23509 - 16
Structure-function analysis of the human insulin-like growth factor binding protein-4; Qin X et al.; To identify the molecular mechanism by which insulin-like growth factor binding protein-4 (IGFBP-4) exerts its inhibitory effects on insulin-like growth factor (IGF) actions, we localized and determined the role of the IGF binding domain in modulating IGF actions in human osteoblasts . Deletion analysis using IGFBP-4 expressed in bacteria revealed that the N-terminal sequence Leu72-Ser91 was essential for IGF binding . The C-terminal fragments (His121-Glu237 or Arg142-Glu237) did not bind to IGF but loss of these regions decreased IGF binding activity . Detailed deletion analysis identified the residues Cys205-Val214 as the motif to facilitate IGF binding . Mitogenic studies revealed that an IGFBP-4 mutant (His74 replaced by Pro74) and an N-terminal peptide (N terminus to Thr71) with little IGF binding activity failed to inhibit IGF-II-induced human osteoblast proliferation . An N-terminal peptide (N terminus to Asn182) with reduced IGF binding activity inhibited IGF action but with lower potency . In contrast, an IGFBP-4 mutant (His74 replaced with Ala74) exhibited similar IGF binding activity and potency in inhibiting the activity of IGF-II compared with the wild type . Therefore, the N-terminal sequence (Leu72-Ser91) and the C-terminal sequence (Cys205-Val214) are necessary to form the high affinity IGF binding domain, which is the major structural determinant of the IGFBP-4 function.

J Biol Chem, 1998 Sep 4, 273(36), 23297 - 303
Structural and transglutaminase substrate properties of the small proline-rich 2 family of cornified cell envelope proteins; Tarcsa E et al.; The small proline-rich (SPR) proteins are components of the cornified cell envelope of stratified squamous epithelia and become cross-linked to other proteins by transglutaminases (TGases) . The SPR2 family is the most complex, as it consists of several differentially expressed members of the same size . To explore their physical and cross-linking properties, we have expressed in bacteria a human SPR2 family member, and purified it to homogeneity . By circular dichroism, it possesses no alpha or beta structure but has some organized structure associated with the central peptide repeat domain . The TGase 1, 2, and 3 enzymes expressed in epithelia use the recombinant SPR2 protein as a complete substrate in vitro, but with widely differing kinetic efficiencies, and in different ways . With TGase 1, only one glutamine on the head domain and one lysine on the tail domain were used for limited interchain cross-linking . With TGase 3, multiple head and tail domain residues were used for extensive interchain cross-linking . The total usage of glutamine and lysine residues in vitro by TGase 3 was similar to that seen in earlier in vivo studies . We conclude that SPR2 proteins are cross-linked in epithelia primarily by the TGase 3 enzyme, a minor extent by TGase 1, and probably not by TGase 2.

J Biol Chem, 1998 Sep 4, 273(36), 23211 - 8
Minimal molecular determinants of substrates for recognition by the intestinal peptide transporter; Doring F et al.; Proton-dependent electrogenic transporters for di- and tripeptides have been identified in bacteria, fungi, plants, and mammalian cells . They all show sequence-independent transport of all possible di- and tripeptides as well as of a variety of peptidomimetics . We used the mammalian intestinal peptide transporter PEPT1 as a model to define the molecular basis for its multisubstrate specificity . By employing computational analysis of possible substrate conformations in combination with transport assays using transgenic yeast cells and Xenopus laevis oocytes expressing PEPT1, the minimal structural requirements for substrate binding and transport were determined . Based on a series of medium chain fatty acids bearing an amino group as a head group (omega-amino fatty acids, omega-AFA), we show that electrogenic transport by PEPT1 requires as a minimum the two ionized head groups separated by at least four methylene groups . Consequently, a > 500 pm < 630 pm distance between the two charged centers (carboxylic carbon and amino nitrogen) is sufficient for substrate recognition and transport . Removal of either the amino group or the carboxyl group in omega-AFA maintained the affinity of the compound for interaction with the transporter but abolished the capability for electrogenic transport . Additional groups in the omega-AFA backbone that provide more hydrogen bonding sites appear to increase substrate affinity but are not essential . The information provided here does (a) explain the capability of the peptide carrier for sequence-independent transport of thousands of different substrates and (b) set the molecular basis for a rational drug design to increase the absorption of peptide-based drugs mediated by PEPT1.

Int J Sports Med, 1998 Jul, 19 Suppl 3, S172 - 82
Acute infection: metabolic responses, effects on performance, interaction with exercise, and myocarditis; Friman G et al.; Acute infections are associated with multiple host responses that are triggered by cytokines and correlated to fever, malaise and anorexia . The purpose of this systemic acute phase host reaction ("the acute phase response") is to mobilize nutrients for the increased needs of the activated immune system, as well as for energy production and tissue repair . Important effects include wasting of striated muscle, degradation of performance-related metabolic enzymes and, concomitantly, deteriorated central circulatory function . These effects result in decreased muscle and aerobic performance, the full recovery of which may require several weeks to months following week-long febrile infections . Also during early infection and fever, prior to the development of muscle wasting, performance is compromised by other mechanisms . Strenuous exercise may be hazardous during ongoing infection and fever and should always be avoided . In infection, muscle wasting seems to be less pronounced in the conditioned (trained) host than in the unconditioned host . Acute myocarditis most often has a viral etiology but bacteria and their toxins may also be the cause . Furthermore, slow-growing bacteria, previously difficult to diagnose, have emerged as potential "new" causes of subacute to chronic myocarditis . Since myocarditis may or may not be associated with fever, malaise, or catarrhal symptoms, athletes should be taught the symptoms suggestive of myocarditis . Whenever myocarditis is suspected exercise should be avoided.

J Clin Periodontol, 1998 Aug, 25(8), 630 - 9
Crevicular fluid level of beta-glucuronidase in relation to clinical periodontal parameters and putative periodontal pathogens in early-onset periodontitis; Albandar JM et al.; Analysis of beta-glucuronidase (betaG) in the gingival crevicular fluid (GCF) provides an indication of neutrophil influx into the crevicular environment . The aim of this study was to test the hypotheses that: (1) betaG is significantly elevated in individuals with early-onset periodontitis (EOP) and that betaG activity correlates with disease severity; and (2) betaG level may reflect the local bacterial challenge in the gingival crevice . The study subjects consisted of a sub-sample of individuals examined in the National Survey of Oral Health of United States Children, which was undertaken during the 1986/87 school year . A total of 249 individuals were selected based on presence or absence of clinical attachment loss at baseline . The individuals were examined a second time 6 years later and the clinical attachment loss was assessed, and subgingival plaque and GCF were collected . The subjects were classified into 3 types of EOP and a control group . BetaG activity in the GCF and the levels of 7 putative micro-organisms in the pocket were assessed . The generalized EOP group had the highest betaG activity, followed by the localized and incidental EOP groups, and the controls, respectively . There was a significant increase in betaG activity with the increase in probing depth . Also, sites with bleeding on probing had a significantly higher betaG activity than sites without bleeding . However, the effect of gingival inflammation on betaG activity was more evident in the generalized and localized EOP groups . Sites harboring high levels of one or more of the micro-organisms tended to have high betaG activity . There were moderate differences between the organisms with respect to their effect on betaG activity, but sites with high numbers of Porphyromonas gingivalis, Prevotella intermedia, or Treponema denticola also had the highest betaG activity . The present findings suggest that betaG activity in GCF from patients with EOP can be of value in the early identification of individuals at higher risk of developing EOP The findings also suggest that host mechanisms leading to higher betaG activity in EOP represent systemic responses and are only partly related to the presence of local factors at the site-level.

J Bacteriol, 1998 Sep, 180(17), 4644 - 9
Expression of glnB and a glnB-like gene (glnK) in a ribulose bisphosphate carboxylase/oxygenase-deficient mutant of Rhodobacter sphaeroides; Qian Y et al.; In a ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO)-deficient mutant of Rhodobacter sphaeroides, strain 16PHC, nitrogenase activity was derepressed in the presence of ammonia under photoheterotrophic growth conditions . Previous studies also showed that reintroduction of a functional RubisCO and Calvin-Benson-Bassham (CBB) pathway suppressed the deregulation of nitrogenase synthesis in this strain . In this study, the derepression of nitrogenase synthesis in the presence of ammonia in strain 16PHC was further explored by using a glnB::lacZ fusion, since the product of the glnB gene is known to have a negative effect on ammonia-regulated nif control . It was found that glnB expression was repressed in strain 16PHC under photoheterotrophic growth conditions with either ammonia or glutamate as the nitrogen source; glutamine synthetase (GS) levels were also affected in this strain . However, when cells regained a functional CBB pathway by trans complementation of the deleted genes, wild-type levels of GS and glnB expression were restored . Furthermore, a glnB-like gene, glnK, was isolated from this organism, and its expression was found to be under tight nitrogen control in the wild type . Surprisingly, glnK expression was found to be derepressed in strain 16PHC under photoheterotrophic conditions in the presence of ammonia.

Mol Microbiol, 1998 Jul, 29(2), 449 - 63
Structural homologues P(II) and P(Z) of Azospirillum brasilense provide intracellular signalling for selective regulation of various nitrogen-dependent functions; de Zamaroczy M; P(II) (glnB) is a signal transduction protein that in Azospirillum brasilense is specifically required for nitrogen fixation . Little is known about whether and how its homologue P(Z) (glnZ) participates in the regulation of cellular functions . In this study, we have shown the regulatory action of the two proteins by analysing the relevant single and double null-mutant strains . The transcription of glnZ is monocistronic, and it starts mainly from a sigma54-dependent promoter, activated by NtrC . glnZ expression is dependent on the ntr system, even under conditions of nitrogen excess, and is greatly enhanced in the presence of aspartate . P(Z) is uridylylated in response to nitrogen limitation, like P(II), although different amounts of the two proteins are synthesized . P(II) is required for the dephosphorylation of NtrC . Thus, in the absence of P(II), the repression of nitrate assimilation is not promoted, which, in turn, leads to a high rate of ammonium excretion . Unexpectedly, P(II) and P(Z) proteins are not essential for the reversible modification of glutamine synthetase . (Methyl)ammonium transport into the cell is negatively regulated by P(Z) . The growth of a double-mutant strain (glnB::kan; glnZ::omega) is drastically disabled, although wild-type growth is restored by complementation with either glnB or glnZ . We conclude that P(II) and P(Z), despite their structural similarity, are involved in different regulatory processes, except for that required for cell growth.

Appl Microbiol Biotechnol, 1998 Jul, 50(1), 129 - 34
Biological degradation of diesel fuel in water and soil monitored with solid-phase micro-extraction and GC-MS; Eriksson M et al.; Solid-phase micro-extraction (SPME) was used for monitoring degradation of hydrocarbons in diesel-fuel-contaminated (1% v/v) water and soil . Natural soil bacteria with and without external addition of inoculum were used . Directly after a 10-s exposure of the sample, the polydimethylsiloxane fibre was injected into the GC-MS . This method strongly reduced the time of analysis compared to a conventional liquid/liquid extraction . A comparison of SPME and pentane extraction of diesel oil was made and found to be consistent . The degradation of diesel fuel in water was monitored for 10 weeks using SPME . After 5 weeks all hydrocarbons were degraded except for the decahydronaphthalenes . These compounds were approximately 3% of the total hydrocarbons in the diesel oil used and remained undegraded throughout the study although none of the chemical or physical parameters was limiting . In the soil study the degradation of diesel fuel in normal soil was completed after 3 weeks, when the only remaining substances were decahydronaphthalenes . All samples were compared to sterile references to make up for evaporation losses . SPME proved to be a fast and reliable method to monitor changes in concentrations of semivolatile organic compounds.

Anim Genet, 1998 Jun, 29(3), 185 - 93
Associations of the bovine major histocompatibility complex DRB3 (BoLA-DRB3) alleles with occurrence of disease and milk somatic cell score in Canadian dairy cattle; Sharif S et al.; Potential associations were investigated between bovine leucocyte antigen (BoLA) alleles and occurrence of disease . Cows (Holstein n = 835; Jersey n = 66) were examined for polymorphisms of the second exon of the BoLA-DRB3 gene, using the polymerase chain reaction (PCR), followed by digestion of the amplified fragments with three restriction endonucleases . Disease occurrences were recorded for each cow throughout one lactation . Milk somatic cell count data were retrieved through the Dairy Herd Improvement records and converted to somatic cell score (SCS) . There were no effects of BoLA alleles on SCS in Jersey cows, but BoLA-DRB3.2*16 was significantly associated (P < or = 0.05) with lower SCS in Holsteins . Since the number of Jerseys was relatively small and prevalence of diseases in this population was low, health records of Jerseys were not analyzed further . BoLA associations with occurrence of disease in Holsteins were investigated using a log-linear model . There was a significant (P < or = 0.05) association between BoLA-DRB3.2*23 and occurrence of severe mastitis, from which coliforms were the most commonly isolated bacteria . The BoLA allele *3 was associated with a lower risk of retained placenta (P < or = 0.05) and alleles *16 (P < or = 0.05) and *22 (P < or = 0.05) with a lower risk of cystic ovarian disease . Although more studies are required to confirm the present findings, it can be concluded that BoLA alleles may have potential usefulness as genetic markers of higher or lower risk of disease occurrence in cows.

Inflamm Res, 1998 Jul, 47(7), 308 - 15
Characterization of rat lung ICAM-1; Beck-Schimmer B et al.; OBJECTIVE AND DESIGN: We expressed soluble rat ICAM-1, generated a polyclonal anti-ICAM-1 antibody, and studied ICAM-1 upregulation in lung inflammatory conditions . Bacterial and baculovirus expression systems were employed . MATERIAL: 250 g adult, male Long Evans rats were used . For in vitro studies, rat pulmonary artery endothelial cells (RPAEC), rat alveolar macrophages and aortic rings were stimulated (as described below) and evaluated for ICAM-1 expression . TREATMENT: RPAEC and macrophages were stimulated with lipopolysaccharide (LPS) and recombinant murine tumour necrosis factor alpha (TNFalpha) . In vivo immunoglobulin G (IgG) immune complex-induced lung injury was employed . METHODS: Enzyme-linked immunoassay (ELISA) Western and Northern blot analyses and immunohistochemical evaluations were performed . All experiments were done at least in duplicate . Data were analyzed by two-tailed Student's t-test . RESULTS: ICAM-1 expression of RPAEC was time- and dose-dependent, peaking at 6h after LPS-stimulation . LPS and TNFalpha each enhanced ICAM-1 expression on alveolar macrophages (reaching a maximum at 2 h) . In IgG immune complex-induced lung injury, ICAM-1 mRNA isolated from whole lung peaked at 4 h, while lung ICAM- I protein peaked at 6 h . CONCLUSIONS: Quantitation of ICAM-1 expression in vitro and in vivo suggests that ICAM-1 plays a central role in two lung inflammatory models . Furthermore, lung ICAM-1 upregulation involves at least two cell types: vascular endothelial cells and alveolar macrophages.

Cancer Lett, 1998 Jul 17, 129(2), 223 - 8
Potent suppressive activity of pheophytin a and b from the non-polyphenolic fraction of green tea (Camellia sinensis) against tumor promotion in mouse skin; Higashi-Okai K et al.; Chlorophyll-related compounds pheophytin a and b have been recently identified as antigenotoxic substances in the non-polyphenolic fraction of green tea (Camellia sinensis), which suppressed umu C gene expression in tester bacteria induced by various genotoxins (Okai and Higashi-Okai, Cancer Lett . 118 (1997) 117-123) . In the present study, the authors analyzed in vivo and in vitro effects of pheophytin a and b from the non-polyphenolic fraction of green tea on tumor promotion in mouse skin as follows . (1) When pheophytin a and b from green tea were topically applied prior to each treatment with a tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA) on BALB/c mouse skin initiated by 7,12 dimethylbenz{a}anthracene (DMBA), they caused suppression in a dose-dependent fashion against skin tumorigenesis . (2) Pheophytin a and b exhibited significant suppressions against TPA-induced inflammatory reaction, such as edema formation, in BALB/c mouse ear skin in a dose-dependent manner . (3) Pheophytin a and b from green tea showed inhibitory effects against early induction of ornithine decarboxylase (ODC) in BALB/c mouse skin fibroblasts caused by TPA . These results suggest that pheophytin a and b from the non-polyphenolic fraction have potent suppressive activities against tumor promotion in mouse skin.

J Dent Res, 1998 Aug, 77(8), 1622 - 9
The activation and function of host matrix metalloproteinases in dentin matrix breakdown in caries lesions; Tjaderhane L et al.; Matrix metalloproteinases (MMPs) are a family of enzymes which, in concert, are capable of degrading collagen . We investigated whether human MMPs could participate in the degradation of dentin organic matrix after demineralization . We performed Western blot analyses using MMP-specific antibodies to identify MMPs in human dental caries lesions . Enzymography and functional activity assays, with 125I-labeled gelatin as substrate or quantitating the degradation of type I collagen, were used to determine the activity of purified and salivary gelatinolytic (MMP-2 and MMP-9) and collagenolytic (MMP-8) enzymes with and without acid-activation in pHs relevant to caries . Respective analyses were done with caries-related bacteria . We performed electron microscope analyses to assess the degradative activity of sterilized salivary host MMPs on demineralized human dentin . Human MMP-2, MMP-8, and MMP-9 were identified in demineralized dentinal lesions . The latent purified forms of these enzymes were activated at low pH (4.5), followed by neutralization, mimicking the conditions during caries progression . Incubation of human saliva at low pH followed by neutralization resulted in a four-fold increase in the gelatinolytic activity . No gelatinolytic or collagenolytic activity was observed in bacterial samples . The activated enzymes in saliva degraded demineralized dentin organic matrix in vitro . These results demonstrate the pH-dependent activation mechanism of MMPs, which may have a distinct role in different physiological and pathological conditions . They further demonstrate that host MMPs, activated by bacterial acids, have a crucial role in the destruction of dentin by caries.

Insect Biochem Mol Biol, 1998 Jul, 28(7), 473 - 82
Purification and characterization of NADH-dependent glutamate synthase from the silkworm fat body (Bombyx mori); Hirayama C et al.; NADH-dependent glutamate synthase (Nadh-Gogat; EC 1.41.14) was purified 766-fold from the fat body of 5th instar larvae of the silkworm with a final specific activity of 13.8 units/mg protein by a produce including ammonium sulfate fraction, Q-Sepharose HP ion exchange column chromatography, Blue Sepharose FF affinity column chromatography and Superdex 200 HR gel filtration . The purified enzyme yielded a single band corresponding to a molecular mass of 195kDa by SDS-polyacrylamide gel electrophoresis . Molecular mass of the native enzyme was estimated to be 190 kDa by Superdex 200HR gel filtration, suggesting that the enzyme is composed of a monomeric polypeptide . The enzyme showed an absorption spectrum with maximum values at 272, 375, and 435 nm, suggesting the presence of a flavin prosthetic group in the enzyme . The N-terminal amino acid sequence showed a high similarity to those of other GOGATs from plants, yeast and bacteria, but no similarity to other known proteins was detected . The enzyme exhibited a strong specificity to the electron donor and substrates; NADH as electron donor, 2-oxoglutarate as amino acceptor and glutamine as amino donor were essential for the catalytic activity . The optimum pH was around 7.5, at which Km values for 2-oxoglutarate, glutamine and NADH were 17, 220 and 5.7 micro M, respectively . Azaserine, 6-diazo-5-oxonorleucine and p-chloromercuribenzoic acid were strong inhibitors of the activity . These result show that NADH-GOGAT in the silkworm fat body strongly resembles other eukaryotic NADH-GOGATs, suggesting that it plays a significant role in ammonia assimilation in the same manner as the other enzymes.

Rev Environ Health, 1998 Jan-Jun, 13(1-2), 73 - 90
Exposure to nitrogen dioxide (NO2) and respiratory disease risk; Chauhan AJ et al.; Epidemiological evidence suggests that exposure to nitrogen dioxide (NO2) through the use of unvented gas cookers in homes is associated with respiratory symptoms . Toxicological evidence, mainly in animal models, suggests that NO2 may increase the susceptibility to infection by viruses and bacteria . This review examines the evidence and proposes mechanisms whereby such exposure may occur, in particular how NO2 may aggravate respiratory symptoms in the presence of coexistent infection.

Mol Biotechnol, 1998 Jun, 9(3), 205 - 23
Peptide and peptidomimetic libraries . Molecular diversity and drug design; al-Obeidi F et al.; Various techniques for generation of peptide and peptidomimetic libraries are summarized in this article . Multipin, tea bag, and split-couple-mix techniques represent the major methods used to make peptides and peptidomimetics libraries . The synthesis of these libraries were made in either discrete or mixture format . Peptides and peptidomimetics combinatorial libraries were screened to discover leads against a variety of targets . These targets, including bacteria, fungus, virus, receptors, and enzymes were used in the screening of the libraries . Discovered leads can be further optimized by combinatorial approaches.

Proteins, 1998 Aug 15, 32(3), 268 - 75
Molecular dynamics study of femtosecond events in photoactive yellow protein after photoexcitation of the chromophore; Yamato T et al.; Molecular dynamics simulations were carried out to study what happens in a photoreceptor protein, photoactive yellow protein (PYP), immediately after the vertical transition of the chromophore from the ground to the excited state . A photon absorption simulation was performed to investigate the movement of amino acid residues upon photoexcitation . To calculate the excited state of the chromophore, SCF-CI calculation was carried out with INDO/S Hamiltonian . We observed that some amino acid residues have strong interactions with the chromophore . Most of these amino acid residues are conserved in PYPs from three different species of bacteria . This observation indicates the biological importance of these residues.

Plant Cell, 1998 Aug, 10(8), 1295 - 306
Maize endosperm ADP-glucose pyrophosphorylase SHRUNKEN2 and BRITTLE2 subunit interactions
Greene TW, Hannah LC.
ADP-glucose pyrophosphorylase (AGP) represents a key regulatory step in polysaccharide synthesis in organisms ranging from bacteria to plants . Higher plant AGPs are complex in nature and are heterotetramers consisting of two similar but distinct subunits . How the subunits are assembled into enzymatically active polymers is not yet understood . Here, we address this issue by using naturally occurring null mutants of the Shrunken2 (Sh2) and Brittle2 (Bt2) loci of maize as well as the yeast two-hybrid expression system . In the absence of the maize endosperm large AGP subunit (SH2), the BT2 subunit remains as a monomer in the developing endosperm . In contrast, the SH2 protein, in the absence of BT2, is found in a complex of 100 kD . A direct interaction between SH2 and BT2 was proven when they were both expressed in yeast . Several motifs are essential for SH2:BT2 interaction because truncations removing the N or C terminus of either subunit eliminate SH2:BT2 interactions . Analysis of subunit interaction mutants (sim) also identified motifs essential for protein interactions.

Mol Endocrinol, 1998 Aug, 12(8), 1184 - 92
Estrogen receptor, a common interaction partner for a subset of nuclear receptors; Lee SK et al.; Nuclear receptors regulate transcription by binding to specific DNA response elements as homodimers or heterodimers . Herein, the yeast and mammalian two-hybrid tests as well as glutathione-S-transferase pull-down assays were exploited to demonstrate that estrogen receptor (ER) directly binds to a subset of nuclear receptors through protein-protein interactions between ligand-binding domains . These receptors include hepatocyte nuclear factor 4, thyroid hormone receptor (TR), retinoic acid receptor (RAR), ERbeta, and retinoid X receptor (RXR) . In yeast cells, a LexA fusion protein to the human ER ligand-binding domain (LexA/ER-LBD) was an inert transactivator of a LacZ reporter gene controlled by upstream LexA-binding sites . However, LexA/ER-LBD differentially modulated the LacZ reporter gene expression when coexpressed with native TRs, RARs, or RXRs . Similarly, cotransfection of these receptors in CV1 cells up- or down-regulated transactivations by ER . From these results, we propose that ER is a common interaction partner for a subset of receptors, and these interactions should mediate novel signaling pathways in vivo.

Arch Oral Biol, 1998 Jun, 43(6), 485 - 96
Experimental chronic infection induced in mice by Actinomyces israelii entrapped in alginate gel; Moral MA et al.; Tissue responses to experimentally induced actinomycotic lesions were investigated in mice by both light and transmission electron microscopy . Micro-organisms of Actinomyces israelii were entrapped in alginate gel and injected into the subcutaneous tissue over the periosteum of the mouse cranium . One day after the injection (initial stage), a non-stained amorphous structure was located in the core of the lesion, corresponding to the injected gel with bacteria . Numerous neutrophils surrounded the core region and phagocytized the injected complex actively . At days 3-7 (intermediate stage), the lesion became well developed . The core structure became eosinophilic and separated to form island-like structures . No lesion was recognized in the control group (gel without bacteria) until day 14 . After 30 days (late stage), the lesions displayed more static features, similar to the "sulphur granules" characteristic of actinomycotic lesions . At the late stage, foamy cells increased in number and took the place of neutrophils in the alginate islands . By transmission electron microscopy these foamy cells were seen to be filled with lysosomal vesicles containing electron-dense foreign material . Thus, these cells appeared to be macrophages that had phagocytized degenerated neutrophils containing bacteria . Along with the active phagocytosis by foamy cells that progressed in the late stage, a collagenous capsule became conspicuous and separated the lesion from the intact tissue . The bacteria remained in the gel islands until at least day 60, although they considerably decreased in number with time . Serum IgG antibody titres began to rise within 24 h of the injection, reached a peak concentration at day 14 and remained a significantly high (p < 0.01, vs 0 time) until day 120 . These results suggest that this animal model is useful for inducing experimental chronic infectious lesions.

Trends Microbiol, 1998 Jul, 6(7), 288 - 94
The ins and outs of peptide signaling; Lazazzera BA et al.; Many bacteria communicate by secreting and responding to extracellular peptides (pheromones) . Some peptide pheromones act via receptors on the cell surface, which are often membrane-bound histidine protein kinases . Other peptide pheromones are transported into the cell by an oligopeptide permease and interact with intracellular receptors to modulate gene expression.

Trends Microbiol, 1998 Jul, 6(7), 263 - 8
Reductive evolution of resident genomes; Andersson SG et al.; Small, asexual populations are expected to accumulate deleterious substitutions and deletions in an irreversible manner, which in the long-term will lead to mutational meltdown and genome decay . Here, we discuss the influence of such reductive processes on the evolution of genomes that replicate within the domain of a host genome.

Int J Oral Maxillofac Implants, 1998 Jul-Aug, 13(4), 465 - 73
Morphologic studies on the biologic seal of titanium dental implants . Report II . In vivo study on the defending mechanism of epithelial adhesions/attachment against invasive factors; Kawahara H et al.; Clinical measurements on gingival indices and morphologic observations were performed in this study to verify the defending mechanism of gingival soft tissue against foreign invasions from the perspective of epithelial adhesion/attachment to implant surfaces in the monkey mandible . The following zones were observed using scanning electron microscopy: (1) plaque zone, suggesting susceptibility of the gingival tissue to bacterial invasion; (2) nude zone, demonstrating indirect adhesion of epithelial cells to the implant surface through the mucous layer and preventing bacterial invasion; and (3) epithelial cell attached zone, having greater bond strength of epithelial cells at the cell-implant interface as compared to cell-cell bonding within the epithelial cell layer . This study suggested that epithelial cell attachment/adhesion may play a dominant role in retaining the successful condition of a dental implant.

Biochim Biophys Acta, 1998 Aug 10, 1366(1-2), 113 - 26
Mitochondria, glutamate neurotoxicity and the death cascade; Montal M; This review focuses on two questions: the role of mitochondria in excitotoxic neuronal death and the connection of mitochondria with the apoptotic death cascade . The goal is to highlight the regulatory role of mitochondrial channels on the mitochondrial membrane potential, Deltapsi, and their involvement in determining neuronal survival or death . A hypothesis is developed centered on the notion that protein-protein interactions between members of the Bcl-2 family of death suppressor and promoter proteins lead to the selective elimination of depolarizing currents that, in turn, collapse Deltapsi and set in motion the irreversible pathway of cell death . The model considers the remarkable propensity of Bcl-2 family proteins to dimerize or oligomerize and thereby restrict the localization of partner molecules to mitochondrial membrane contact sites . The fundamental principle invoked here is that through a concerted set of protein-protein interactions, information is exchanged by specific heterodimers, one of the partners acting as a toxic protein and the second as its antidote . The review concludes with the elaboration of a speculative model about cellular mechanisms for the prevention of cell destruction as triggered by extracellular signals which may be conserved in its molecular design from bacteria to eukaryotes.

Biochim Biophys Acta, 1998 Jul 30, 1399(1), 31 - 9
Cloning and characterization of the genes coding for two porins in the unicellular cyanobacterium Synechococcus PCC 6301; Hansel A et al.; The genes somB and somA (Synechococcus outer membrane), lying in tandem organization in the genome of Synechococcus PCC 6301, encode two porins in the outer membrane of this unicellular cyanobacterium . Northern blot and primer extension experiments revealed that somA and somB are not comprising an operon, as each gene encodes a transcript of 1.7 kb length and has a distinct transcriptional start site . The deduced SomA and SomB protein sequences include typical N-terminal signal peptides and reveal 60% homology (50% identical residues) to each other as well as significant homology to six protein sequences deduced from open reading frames sequenced in the genome of the unicellular cyanobacterium Synechocystis PCC 6803 . Furthermore, SomA possesses an overall identity of 97% to the functionally not yet characterized outer-membrane protein SomA from the closely related cyanobacterial strain Synechococcus PCC 7942 . Analyses performed on the sequences suggest that SomA and SomB form 14- or 16-stranded porin-like beta-barrels . Moreover, all sequences share an N-terminal motif with significant homology to 'S-layer homology' domains, which might form a periplasmic extension . SomA and SomB therefore may, in addition to their porin function, act as linkers connecting the outer membrane with the peptidoglycan layer.

Biochem Pharmacol, 1998 Jun 1, 55(11), 1835 - 42
Role of nitric oxide in the inhibition of cytochrome P450 in the liver of mice infected with Chlamydia trachomatis; Khatsenko OG et al.; In this study, we attempted to determine the effect of a systemic infection with Chlamydia trachomatis on cytochrome P450(CYP)-dependent metabolism in mice . Furthermore, we wanted to assess if these effects were mediated through NO . BALB/c(H-2d) female mice were inoculated intraperitoneally with the C . trachomatis mouse pneumonitis (MoPn) biovar, and induction of NO synthase (NOS) was detected by measuring {NOx} levels and inducible NOS protein content in peritoneal macrophages by Western blotting . Recovery of C . trachomatis from liver, lung, and spleen peaked at 4 days postinfection . Following cotreatment with N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthase, there was a significant increase in the intensity and the length of the infection . Six days after inoculation with C . trachomatis, CYP1A- and CYP2B-mediated metabolism in the liver of the mice was diminished up to 49% of control levels . However, when animals were treated with N(G)-nitro-L-arginine methyl ester at days 4 and 6 postinfection, the decrease in the metabolism of CYP1A and CYP2B was largely blocked . These results suggest that C . trachomatis infection can depress cytochrome P450 in a manner similar to other types of infections and that NO is likely to be a mediator of this depression . This finding may be of significance to patients taking drugs that are metabolized by phase I enzymes during infections with some bacteria such as C . trachomatis.

Acta Gastroenterol Latinoam, 1998, 28(2), 199 - 201
{Is dental plaque a normal Helicobacter pylori reservoir?}; Amendola R et al.; The mechanisms of transmission and reservoir of Helicobacter pylori is still unclear; even it has been suggested that dental plaque could be the bacterial reservoir and one important factor in the reinfection . The aim of the study was to evaluate the prevalence of Helicobacter pylori in dental plaque in 20 patients with non ulcer dyspepsia (12 females, 7 males; mean age 40.5 years) and antral infection; and to establish the presence of bacteria in dental plaque and gastric mucosa after eradication . Gastric colonization in all of them was confirmed by five samples (three of antrum and two of body) with Giemsa conventional technique, clotest and culture . When clotest was positive in gastric mucosa, we performed the scrape of dental plaque and sending the material for culture . All patients were treated with a scheme of seven days with one protom pump inhibitor and two antibiotics . After four weeks all the patients were controlled with endoscopy and culture of dental plaque to confirm eradication . Dental plaque culture was positive in 1/20 patients (5%), and this results was similar to developed countries, using as detection method culture or polymerase chain reaction (PCR).

J Biol Chem, 1998 Aug 28, 273(35), 22648 - 56
Translational inhibition in vitro of human papillomavirus type 16 L2 mRNA mediated through interaction with heterogenous ribonucleoprotein K and poly(rC)-binding proteins 1 and 2; Collier B et al.; Human papillomavirus (HPV) type 16 belongs to the group of "high risk" HPV types that are frequently detected in anogenital cancers . The expression of HPV-16 late genes encoding the virus capsid proteins L1 and L2 is restricted to terminally differentiated epithelial cells in the superficial layers of the squamous epithelium . We have previously identified negative elements in the 3' end of L2 RNA that act in cis to reduce mRNA utilization without substantially affecting mRNA levels . The experiments reported here demonstrate the interaction of cellular proteins with an inhibitory sequence present in the coding region of the L2 mRNA . Using RNA gel shift assays and UV cross-linking, we have detected three cellular proteins interacting specifically with the sense strand of the L2 mRNA, two of which were identified as heterogeneous ribonucleoprotein K (hnRNP K) and the poly(rC) binding- protein (PCBP) . Recombinant hnRNP K, PCBP-1, and PCBP-2 that were over expressed in bacteria and partially purified bound to the HPV-16 L2 mRNA in a sequence-specific manner . Interestingly, PCBP-1, PCBP-2, and hnRNP K specifically and efficiently inhibited translation of the HPV-16 L2 mRNA in vitro . Therefore, these proteins may play an important role in the regulation of HPV-16 late gene expression and virus production in vivo.

J Biol Chem, 1998 Aug 28, 273(35), 22506 - 14
Characterization of interactions between the anti-apoptotic protein BAG-1 and Hsc70 molecular chaperones; Stuart JK et al.; The anti-cell death protein BAG-1 binds to 70-kDa heat shock proteins (Hsp70/Hsc70) and modulates their chaperone activity . Among other facilitory roles, BAG-1 may serve as a nucleotide exchange factor for Hsp70/Hsc70 family proteins and thus represents the first example of a eukaryotic homologue of the bacterial co-chaperone GrpE . In this study, the interactions between BAG-1 and Hsc70 are characterized and compared with the analogous GrpE-DnaK bacterial system . In contrast to GrpE, which binds DnaK as a dimer, BAG-1 binds to Hsc70 as a monomer with a 1:1 stoichiometry . Dynamic light scattering, sedimentation equilibrium, and circular dichroism measurements provided evidence that BAG-1 exists as an elongated, highly helical monomer in solution . Isothermal titration microcalorimetry was used to determine the complex stoichiometry and an equilibrium dissociation constant, KD, of 100 nM . Kinetic analysis using surface plasmon resonance yielded a KD consistent with the calorimetrically determined value . Molecular modeling permitted a comparison of structural features between the functionally homologous BAG-1 and GrpE proteins . These data were used to propose a mechanism for BAG-1 in the regulation of Hsp70/Hsc70 chaperone activity.

Infect Immun, 1998 Sep, 66(9), 4469 - 73
Role of immunoglobulin A monoclonal antibodies against P23 in controlling murine Cryptosporidium parvum infection; Enriquez FJ et al.; Cryptosporidium parvum is an important diarrhea-causing protozoan parasite of immunocompetent and immunocompromised hosts . Immunoglobulin A (IgA) has been implicated in resistance to mucosal infections with bacteria, viruses, and parasites, but little is known about the role of IgA in the control of C . parvum infection . We assessed the role of IgA during C . parvum infection in neonatal mice . IgA-secreting hybridomas were developed by using Peyer's patch lymphocytes from BALB/c mice which had been orally inoculated with viable C . parvum oocysts . Six monoclonal antibodies (MAbs) were selected for further study based on indirect immunofluorescence assay reactivity with sporozoite and merozoite pellicles and the antigen (Ag) deposited on glass substrate by gliding sporozoites . Each MAb was secreted in dimeric form and recognized a 23-kDa sporozoite Ag in Western immunoblots . The Ag recognized comigrated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with P23, a previously defined neutralization-sensitive zoite pellicle Ag . MAbs were evaluated for prophylactic or therapeutic efficacy against C . parvum, singly and in combinations, in neonatal BALB/c mice . A combination of two MAbs given prophylactically prior to and 12 h following oocyst challenge reduced the number of intestinal parasites scored histologically by 21.1% compared to the numbers in mice given an isotype-matched control MAb (P < 0.01) . Individual MAbs given therapeutically in nine doses over a 96-h period following oocyst challenge increased efficacy against C . parvum infection . Four MAbs given therapeutically each reduced intestinal infection 34.4 to 42.2% compared to isotype-matched control MAb-treated mice (P < 0.05) . One MAb reduced infection 63.3 and 72 . 7% in replicate experiments compared to isotype-matched control MAb-treated mice (P < 0.0001) . We conclude that IgA MAbs directed to neutralization-sensitive P23 epitopes may have utility in passive immunization against murine C . parvum infection.

Infect Immun, 1998 Sep, 66(9), 4108 - 14
A peptide domain on gingipain R which confers immunity against Porphyromonas gingivalis infection in mice; Genco CA et al.; The cysteine proteinases referred to as gingipains R (gingipain R1 and gingipain R2) and gingipain K produced by Porphyromonas gingivalis are virulence factors of this periodontal pathogen which likely act by interrupting host defense mechanisms and by participating in the penetration and destruction of host connective tissue . To examine the effect of immunization with gingipains R on the ability of P . gingivalis to colonize and invade in the mouse chamber model, BALB/c mice were immunized intraperitoneally with the 95-kDa gingipain R1, the 50-kDa gingipain R2, or multiple antigenic peptide (MAP)-conjugated gingipain R-derived peptides and then challenged with P . gingivalis . Immunization of mice with the 95-kDa gingipain R1, the 50-kDa gingipain R2, or a peptide derived from the N-terminal sequence of the catalytic domain of gingipains R (peptide A) followed by challenge with P . gingivalis A7436 resulted in protection from P . gingivalis invasion . In contrast, immunization with peptides corresponding to either a sequence encompassing the catalytic cysteine residue of gingipains R (peptide B) or an identical sequence within the catalytic domains of gingipain R1 and gingipain K (peptide C), followed by challenge with P . gingivalis, did not protect animals, nor did immunization with a peptide corresponding to sequences within the adhesion/hemagglutinin domain of gingipain R1 (peptide D) which have been shown to be directly involved in the hemagglutinin activity of gingipain R1 . However, the immunoglobulin G (IgG) titer obtained following immunization with peptide D was comparable to that obtained following immunization with the N-terminal peptide (peptide A) . Competitive enzyme-linked immunosorbent assays, using either the 95-kDa gingipain R1 or gingipain K as the competing soluble antigen, indicated that 42 and 53% of the antibodies induced by immunization with heat-killed bacteria recognize gingipain R1 and gingipain K, respectively; however, even at very high concentrations, the 50-kDa gingipain R2 did not hinder IgG binding to P . gingivalis . These results indicate that antibodies directed to the amino-terminal region of the catalytic domain of gingipains R are capable of inducing a protective immune response against P . gingivalis infection in the mouse chamber model.

Hum Pathol, 1998 Aug, 29(8), 846 - 50
Intestinal metaplasia with adherent Helicobacter pylori: a hybrid epithelium with both gastric and intestinal features; Ota H et al.; Helicobacter pylori seem to avoid areas of intestinal metaplasia in the gastric mucosa, but attachment of these bacteria to epithelium with the appearance of incomplete intestinal metaplasia has been documented . To characterize the nature of the epithelium to which H pylori was attached, we carried out an immunohistochemical study using monoclonal antibodies against gastric surface mucous cell mucins (M1), blood group-related carbohydrates antigens (Le(a), sialyl Le(a), Le(b), type 1H, and type 2H) and sialyl Tn antigen . The results of this study suggest that these areas of H pylori attachment represent a hybrid epithelium whose cells share characteristics of both gastric surface mucous cells and intestinal metaplastic cells . Whether all areas of incomplete intestinal metaplasia represent an intermediate stage between the normal gastric epithelium and the fully developed complete type of metaplasia remains to be determined.

Carbohydr Res, 1998 Jun, 308(3-4), 423 - 9
Acceptor specificity of cellobiose phosphorylase from Cellvibrio gilvus: synthesis of three branched trisaccharides; Percy A et al.; Cellobiose phosphorylase from Cellvibrio gilvus was examined for its acceptor specificity in the synthetic reaction with glucose-1-phosphate, using substrates in which the C-6 substituent of D-Glc had been altered . A range of disaccharides were also tested for acceptor specificity but only those with (1-->6)-linkages were successful acceptors . Melibiose, gentiobiose, isomaltose and also the monosaccharide glucuronamide were found to react with cellobiose phosphorylase and glucose-1-phosphate giving beta-D-Glcp-(1-->4)-{alpha-D-Galp-(1-->6)}-D-Glcp, beta-D-Glcp-(1-->4)-{beta-D-Glcp-(1-->6)}-D-Glcp, beta-D-Glcp-(1-->4)-{alpha-D-Glcp-(1-->6)}-D-Glcp and beta-D-Glcp-(1-->4)-D-GlcUNp, respectively . These products were purified using a range of chromatographic methods and characterised by NMR and FAB-MS . This is the first time cellobiose phosphorylase has been shown to synthesise trisaccharides.

Vaccine, 1998 Aug-Sep, 16(14-15), 1396 - 400
Infant B cell responses to polysaccharide determinants; Rijkers GT et al.; Newborns and infants up to the age of 1.5-2 years of age are unable to produce antibodies to bacterial capsular polysaccharides . As a consequence, children up to the age of 2 years have an increased susceptibility for infections with encapsulated bacteria . Capsular polysaccharides are classified as so-called T cell independent type 2 antigens and induce IgG2 antibodies . The mechanism of B lymphocyte activation by polysaccharides differs from that of protein antigens and involves co-stimulation by CD21 (type 2 complement receptor) . Reduced expression of CD21 on neonatal B lymphocytes can explain unresponsiveness to polysaccharides . Polysaccharide protein conjugates have the ability to overcome unresponsiveness to polysaccharides early in life . The response induced is predominant IgGl.

Biol Res, 1997, 30(3), 117 - 23
Non random DNA evolution; Valenzuela CY; A model for testing random molecular evolution is proposed . Randomness of recurrent mutation is defined based on isotropy and zero covariance among nucleotide sites . Assuming an equal rate of mutation for the bases A, T, G, and C, in both DNA strands, a mutational matrix of transformation A, T, G, and C with 6 parameters is developed . Under this model the equilibrium proportions (F) of the bases are FA = FT = (D + E)/{2(D + E + H + J)} and FG = FC = (H + J)/{2(D + E + H + J)}, D, E, H, J being 4 of the 6 matrix parameters . Thus the expected (FA + FT)/(FG + FC) ratio can also be tested . If the average rate of mutation is 10(-8) per nucleotide site and cell replication, the equilibrium for every site, in most species, is reached in 10(8) years . Eight DNA segments from human, bacteria, fungus and insect genomes were chosen to test these proportions and their heterogeneity among coding and non coding subsegments . While FG was similar to FC as expected, FA was highly different from FT Huge heterogeneities were found between coding and non coding segments and among non coding segments . These results are a strong evidence for non randomness of molecular evolution.

Cytopathology, 1998 Aug, 9(4), 222 - 9
Fine needle aspiration (FNA) in HIV+ patients: results from a series of 655 aspirates; Ellison E et al.; There are many selected small series or case reports of FNAs in patients with HIV infection, but large series are rare and epidemic's characteristics have evolved over time . The current study, from a large public hospital in the USA, included women as well as men, hetero- and homosexuals, in-patients and out-patients, and deep radiologically guided aspirates as well as superficial masses . Of 655 FNAs, reactive or benign changes were present in 37% confirmed or suspected malignancy in 13%, specific infection with stainable organisms in 14%, and inflammation in 16% . Twenty percent of cases were inadequate for diagnosis . Most of the identifiable infections were associated with Mycobacterium tuberculosis, with fewer atypical mycobacteria, fungi and other bacteria . Clinically significant diagnoses were correlated with deep aspirate location and lesion size > 2 cm, confirming other studies which also identified tenderness and recent enlargement as important indicators . The liberal use of FNA in our HIV+ population has greatly reduced the necessity for surgical nodal resection, reassured clinicians in continuing observation of reactive lymphadenopathy, and allowed immediate therapy for specific infection, cyst or malignancy.

Dent Update, 1998 Jan-Feb, 25(1), 23 - 8, 30-2, 34
The status of indirect restorative dental materials; Brown D; The ideal restorative material should enable restoration of teeth that have either suffered trauma or have been prepared during the removal of caries to their original function and appearance . At the same time a seal should develop between the material and the tooth to prevent bacteria-laden fluids from permeating the dentine and reaching the pulp . Few, if any, of the available materials fulfil these requirements . This, the second of a short series, considers the status of indirect restorative materials as the millennium approaches . In this review indirect restorative materials are regarded as those which call not only upon the dexterity and judgement of the dental practitioner, but also upon the skills of the dental technician and techniques of construction that are suitable for use only in a laboratory . Included in this group are the dental casting and bonding alloys, dental ceramics and those resin composites that are shaped, cured and finished in the laboratory.

Biochemistry, 1998 Aug 18, 37(33), 11399 - 404
Correlation between protein flexibility and electron transfer from QA-* to QB in PSII membrane fragments from spinach; Garbers A et al.; To analyze a possible correlation between the extent of QA-* reoxidation and protein dynamics, fluorometric and Mossbauer spectroscopic measurements were performed in photosystem II membrane fragments from spinach . Numerical evaluation of the flash-induced change of the normalized fluorescence quantum yield revealed that the extent of reoxidation starts to decrease below 275 K and is almost completely suppressed at 230 K . Detailed analyses of Mossbauer spectra measured at different temperatures in 57Fe-enriched material indicate that the onset of fluctuations between conformational substates of the protein matrix occurs also at around 230 K . Based on this correspondence, protein flexibility is inferred to play a key role for QA-* reoxidation in photosystem II . Taking into account the striking similarities with purple bacteria and the latest structural information on these reaction centers {Stowell, M . H . B., McPhillips, T . M., Rees, D . C., Soltis, S . M., Abresch, E., and Feher, G . (1997) Science 276, 812-816}, it appears most plausible that also the headgroup of plastoquinone-9 bound to the QB-site in PSII requires a structural reorientation for its reduction to the semiquinone.

J Food Prot, 1998 Jan, 61(1), 66 - 72
Salt balance and rennet clotting properties of cow's, ewe's, and goat's milks preserved with carbon dioxide; de La Fuente MA et al.; Cow's, ewe's, and goat's milk samples were treated with carbon dioxide gas until a pH of 6.1 was reached and stored at 4 degrees C to determine the resulting modifications in the mineral balance . The amounts of calcium and phosphorus dissolved during the acidification were similar in the three species . The acidification with CO2 produced the dissolution of phosphorus and magnesium in concentrations similar to those attained by acidification with lactic acid or hydrochloric acid . Still, the contents of soluble calcium and ionic calcium were higher with the CO2 treatment . The increase of ionic calcium due to the addition of CO2 could explain why milk subjected to such treatment is better suited for coagulation . Removal of added CO2 by shaking the milk for several hours at atmospheric pressure resulted in a higher concentration of ionic-calcium than was found in control milks to which no CO2 had been added . Thus the addition of CO2 improved milk's technological suitability for cheesemaking.

Plant Cell, 1998 Aug, 10(8), 1321 - 32
EIN4 and ERS2 are members of the putative ethylene receptor gene family in Arabidopsis; Hua J et al.; The Arabidopsis ethylene receptor gene ETR1 and two related genes, ERS1 and ETR2, were identified previously . These three genes encode proteins homologous to the two-component regulators that are widely used for environment sensing in bacteria . Mutations in these genes confer ethylene insensitivity to wild-type plants . Here, we identified two Arabidopsis genes, EIN4 and ERS2, by cross-hybridizing them with ETR2 . Sequence analysis showed that they are more closely related to ETR2 than they are to ETR1 or ERS1 . EIN4 previously was isolated as a dominant ethylene-insensitive mutant . ERS2 also conferred dominant ethylene insensitivity when certain mutations were introduced into it . Double mutant analysis indicated that ERS2, similar to ETR1, ETR2, ERS1, and EIN4, acts upstream of CTR1 . Therefore, EIN4 and ERS2, along with ETR1, ETR2, and ERS1, are members of the ethylene receptor-related gene family of Arabidopsis . RNA expression patterns of members of this gene family suggest that they might have distinct as well as redundant functions in ethylene perception.

Curr Biol, 1998 Jul 30-Aug 13, 8(16), R578 - 81
Protein secretion: getting folded proteins across membranes; Stephens C; Work on metalloprotein export in bacteria, and protein import into chloroplasts, has converged in the recognition of a novel membrane translocation system with two fascinating properties: it is driven energetically by the transmembrane pH gradient, and it is capable of translocating folded proteins.

J Wildl Dis, 1998 Jul, 34(3), 508 - 23
Pathology of diseases in wild desert tortoises from California; Homer BL et al.; Twenty-four ill or dead desert tortoises (Gopherus agassizii) were received between March 1992 and July 1995 for necropsies from the Mojave and Colorado deserts of California (USA) . Diseases observed in these animals included cutaneous dyskeratosis (n = 7); shell necrosis (n = 2); respiratory diseases (n = 7); urolithiasis (n = 3); and trauma (n = 5) . In tortoises with cutaneous dyskeratosis the horn layer of shell was disrupted by multiple crevices and fissures and, in the most severe lesions, dermal bone showed osteoclastic resorption, remodeling, and osteopenia . In tortoises with shell necrosis, multiple foci of necrotic cell debris and heterophilic inflammation within the epidermal horn layer were subtended by necrotic dermal bone colonized by bacteria and fungi . Of the seven tortoises with respiratory disease, five were diagnosed with mycoplasmosis . The diagnosis of mycoplasmosis was based on the presence of chronic proliferative rhinitis and positive serologic tests and/or isolation of Mycoplasma sp . Chronic fungal pneumonia was diagnosed in one tortoise with respiratory disease . In the three tortoises with urolithiasis, two were discovered dead, and the live tortoise had renal and articular gout . Traumatic injuries consisted of one tortoise entombed within its burrow, one tortoise burned in a brush fire, two tortoises struck by moving vehicles, and one tortoise attacked by a predator . While the primary cause of illness could be attributed to one or two major disease processes, lesions were often found in multiple organ systems, and a variety of etiologies were responsible for morbidity and mortality.

Annu Rev Nutr, 1998, 18, 385 - 411
Nitrogen cycling in the gut; Fuller MF et al.; This review examines the involvement of the gastrointestinal tract in the utilization of nitrogen, the identities of the nitrogenous substances entering and leaving the gut, and the significance of this recycling in the overall nitrogen economy of the body . It is concerned with nonruminant mammals, including man.

J Membr Biol, 1998 Sep 1, 165(1), 11 - 8
Voltage-dependent closing of porin channels: analysis of relaxation kinetics; Mathes A et al.; The anion-selective porin Omp34 from Acidovorax delafieldii was unidirectionally reconstituted in planar lipid membranes . Pore closing was recorded particularly at low salt conditions for negative and positive membrane potentials in the range of +/-10 to +/-100 mV . Relaxation curves were fitted by exponential functions in order to describe and to analyze the voltage-dependent behavior . Omp34 exhibited the following characteristics: (i) The channels are asymmetric with respect to closing characteristics and corresponding functional parameters . (ii) Relaxation curves can be fitted by a single exponential function in the low voltage range only, at >/=40 mV combinations of two exponential functions are required . (iii) Beyond 60 to 70 mV a third exponential function is necessary to fit the fast closing components properly . The time constants differ by two to three orders of magnitude . (iv) Hysteresis in I-V-diagrams originate from slow relaxation components which are different for positive and negative voltages . The implications for models aiming at description of voltage-dependent closing are discussed.

J Histochem Cytochem, 1998 Sep, 46(9), 1073 - 6
Simultaneous visualization of the yellow and green forms of the green fluorescent protein in living cells; Baumann CT et al.; In this study we sought to develop a method for the co-localization of proteins in living cells utilizing the enhanced green fluorescent protein (EGFP) and a red-shifted EGFP variant, EYFP (enhanced yellow fluorescent protein) . EYFP was expressed as an unsubstituted molecule while EGFP was fused to NF1 (EGFP-NF1), a transcription factor found exclusively in the nucleus . The Leica TCS SP laser scanning confocal microscope was used . This microscope allows the user to monitor the emitted light at defined wavelengths owing to the presence of a monochrometer in the emission light path . pEGFP-NF1 and pEYFP were co-expressed in the same cell and excited with the 476-nm and 488-nm argon laser lines . To separate the EYFP and EGFP fluorescence, EGFP-NF1 emission was recorded between 496 and 505 nm . These wavelengths are on the left shoulder of the EGFP emission peak and exclude most of the EYFP fluorescence . The EYFP emission was followed between 670 and 754 nm, utilizing the tail of EYFP emission that extends well beyond that for EGFP . Under these conditions we obtained excellent discrimination between EYFP fluorescence and EGFP-NF1 emission . These observations demonstrate that EYFP- and EGFP-substituted chimeras can be used for simultaneous detection in living cells.

Curr Microbiol, 1998 Aug, 37(2), 88 - 93
Helicobacter pylori in liquid culture: evaluation of growth rates and ultrastructure; Kitsos CM et al.; This study investigated the growth of Helicobacter (H.) pylori in Brucella broth supplemented with either IsoVitaleX (1% vol/vol), hemin (.01% wt.vol), agar (0.3% wt/vol), or blood agar blocks (1.5% wt/vol agar) . IsoVitaleX was found to significantly shorten the lag phase, while hemin inhibited the growth within the first 24 hours but later acted as a growth stimulant . There was a tendency toward stronger growth when blood agar blocks were added to the medium . Subsequent electron microscopic evaluation revealed that cells of H . pylori were attached to blood agar block surfaces . In contrast, the supplementation of Brucella broth with agar did not significantly increase the cell density . When H . pylori was grown in the presence of IsoVitaleX, strongly stainable electron-dense bodies (140-200 nm) were seen in the cytoplasms . Incubation of cultures on rotary shakers at 10 rpm significantly enhanced growth . The addition of glycerol (15% vol/vol) or fetal bovine serum (15% vol/vol) showed good ultrastructural preservation of bacteria with undamaged cell walls and cytoplasmic membranes, and cytoplasms were ribosome-dense . Cell counts revealed that cultures stored in glycerol or fetal bovine serum had a significantly lower loss in viability when compared with cultures stored without cryopreservatives . Unprotected cells of H . pylori showed on electron micrographs, clumping, cell lysis, and flagellar damage . Finally, the survival rates of H . pylori after multiple thawing from storage at -80 degrees C were best in Brucella broth/glycerol, Brucella broth/fetal bovine serum, and Brucella broth without cryopreservative (in descending order).

Nucleic Acids Res, 1998 Sep 1, 26(17), 4068 - 77
The human DEVH-box protein Ski2w from the HLA is localized in nucleoli and ribosomes; Qu X et al.; The human helicase gene SKI2W is located between RD and RP1 in the class III region of the major histocompatibility complex . Transcripts of SKI2W are detectable in RNA samples isolated from multiple tissues . The protein product Ski2w shares striking amino acid sequence similarities to the yeast antiviral protein Ski2p that controls the translation of mRNAs, probably based on the mRNA structural integrity . Whether this translational regulation mechanism for cellular and viral RNAs exists in mammals is under investigation . Antisera against human Ski2w were generated using fusion proteins produced in bacteria or insect cells . Western blot analysis showed that the endogenous Ski2w protein is approximately 140 kDa in size and is enriched in polysomal fractions of cytoplasmic extracts from HeLa cells . Ribosomal profile studies revealed that Ski2w distributed throughout the entire sucrose gradient in the presence of Mg2+, but co-sedimented with the 18S rRNA-containing 40S subunit and the small ribosomal subunit protein S27a in the presence of EDTA . The co-sedimentation of Ski2w with the 40S subunit is not affected by RNase A treatment of the cell extract, or the addition of KCl to 0.5 M, suggesting that Ski2w is associated with the 40S ribosomal subunit . Indirect immunofluorescence experiments showed that human Ski2w is localized in the nucleoli and in the cytoplasm . In essence, human Ski2w is present at the sites of ribosome biogenesis and protein synthesis.

J Clin Microbiol, 1998 Sep, 36(9), 2755 - 8
Nasal granuloma caused by Scedosporium apiospermum in a dog; Cabanes FJ et al.; A 10-month-old male American Staffordshire terrier was presented to the Autonomous University of Barcelona Veterinary Teaching Hospital because of a 6-month history of a mucopurulent bilateral nasal discharge . The dog had not responded to antibiotics . A follow-up X ray revealed a mixed pattern of osteolysis and increased radiodensity confined to the nasal cavity . Histologic sections of the biopsy specimens revealed the presence of granules containing numerous septate hyphae that were hyaline to pale brown and smooth, one-celled, subspherical-to-elongate conidia that were hyaline to brownish green, and bacteria . Cultures yielded numerous colonies belonging to Scedosporium apiospermum . Susceptibility tests were performed on the isolated strain . The isolate was sensitive to ketoconazole, intermediate to clotrimazole, and resistant to amphotericin B, 5-fluorocytosine, fluconazole, and itraconazole . The dog was treated with oral ketoconazole . During the treatment a general improvement in the lesions was observed . To our knowledge, S . apiospermum has not been implicated previously as an etiologic agent of nasal disease in dogs . This report provides its first description as such.

J Clin Microbiol, 1998 Sep, 36(9), 2499 - 502
Cat scratch disease: the rare role of Afipia felis; Giladi M et al.; Since its isolation in 1988, Afipia felis has been associated with cat scratch disease (CSD) in only one report and its role in CSD has been questioned . We have cultured A . felis from a lymph node of a patient with CSD . 16S rRNA gene sequencing, DNA relatedness studies, fatty acid analysis, and PCR of the A . felis ferredoxin gene showed that the isolate is identical to the previously reported A . felis isolate . To determine the role of A . felis in CSD, PCR of the 16S rRNA gene followed by hybridizations with specific probes were performed with lymph node specimens from CSD patients . All 32 specimens tested positive for Bartonella henselae and negative for A . felis . We conclude that A . felis is a rare cause of CSD . Diagnostic tests not conducive to the identification of A . felis might cause the diagnosis of CSD due to A . felis to be missed.

J Clin Microbiol, 1998 Sep, 36(9), 2399 - 403
Differentiation between Mycobacterium tuberculosis and Mycobacterium avium by amplification of the 16S-23S ribosomal DNA spacer; Sansila A et al.; Differentiation between Mycobacterium tuberculosis and M . avium is helpful for the treatment of disseminated mycobacterial infection in AIDS patients . This can traditionally be done by time-consuming biochemical tests or with Accuprobe . Previously, PCR restriction enzyme analysis (PCR-REA) of the 16S-23S rRNA gene spacer was shown to be able to identify a limited number of strains of Mycobacterium . In this study the method was improved by using more specific primers and was tested with 50 clinical isolates of M . tuberculosis and 65 clinical isolates of M . avium complex . Probes specific to the spacers of M . tuberculosis and M . avium were also tested . Both M . tuberculosis and M . avium could be reliably identified either by PCR-REA or by PCR-hybridization, with the results completely agreeing with those obtained by biochemical tests and with the Accuprobe, respectively . The method may therefore be useful as an alternative in-house method for identification of the bacteria.

Biol Chem, 1998 Jul, 379(7), 847 - 55
Ribosomal protection from tetracycline mediated by Tet(O): Tet(O) interaction with ribosomes is GTP-dependent; Trieber CA et al.; Tet(O) mediates tetracycline resistance by protecting the ribosome from inhibition . A recombinant Tet(O) protein with a histidine tag was purified and its activity in protein synthesis characterized . Tetracycline inhibited the rate of poly(Phe) synthesis, producing short peptide chains . Tet(O)-His was able to restore the elongation rate and processivity . 70S ribosomes bound tetracycline with high affinity . Tet(O)-His in the presence of GTP, but not GDP or GMP, reduced the affinity of the ribosomes for tetracycline . Non-hydrolyzable GTP analogs in the presence of the factor were also able to interfere with tetracycline binding . Ribosomes increased the affinity of Tet(O)-His for GTPgammaS . Tet(O), 70S ribosomes and GTPgammaS formed a complex that could be isolated by gel filtration . The GTP conformer is the active form of Tet(O) that interacts with the ribosome . GTP binding is necessary for Tet(O) activity.

Equine Vet J, 1998 Jul, 30(4), 324 - 8
Serum gentamicin concentrations in compromised neonatal foals; Raisis AL et al.; Twenty-one compromised neonatal foals hospitalised at the Rural Veterinary Centre (RVC) during 1993 were studied to determine i) serum gentamicin concentrations obtained when gentamicin was administered at 3.3 mg/kg bwt twice daily i.m.; ii) factors which contributed to inter-foal variation in serum gentamicin concentrations achieved and iii) clinical efficacy of gentamicin therapy in foals with confirmed septicaemia . Septicaemia was confirmed in 7 foals with positive blood cultures and suspected in 8 foals with a sepsis score > 11 . Peak serum concentrations (Ps) were > 6 microg/ml in all foals and > 8 microg/ml in 60% of foals . Trough serum concentrations (Ts) were < 2 microg/ml in all foals . Factors found to produce inter-foal variation in the Ps achieved included age (< 24 h; decreased), bodyweight (< 38 kg; decreased) and severity of dehydration (8-12% bodyweight; increased) . Clinical response was not associated with achievement of Ps > 8 microg/ml, but was negatively influenced by the severity of clinical signs of depression . None of the foals in this study developed septic arthritis or pneumonia during or after therapy . No serum biochemical evidence (i.e . elevated serum creatinine concentrations) of gentamicin-induced nephrotoxicity was noted during therapy.

Acta Vet Hung, 1998, 46(1), 71 - 84
Endocrine and reproductive consequences of certain endotoxin-mediated diseases in farm mammals: a review; Janosi S et al.; After giving an overview of the general pathology of endotoxin-mediated diseases, the authors summarise the endotoxin-induced endocrine changes and their clinical consequences, with particular regard to reproduction . The consequences of temporary activation of the cyclooxygenase-2 and lipoxygenase enzyme systems resulting in elevated release of various prostanoids are discussed in cyclic and pregnant ruminants, sows and mares . The clinical failures attributable to increased glucocorticoid secretion as well as the endotoxin-induced changes in thyroid function and in peripheral level of some other hormones (prolactin, growth hormone and insulin-like growth factor 1) are also reviewed.

Vox Sang, 1998, 74 Suppl 2, 441 - 5
The French haemovigilance system; Noel L et al.; Haemovigilance was part of the reform of the French transfusion system . The haemovigilance network is now operational with approximately 4600 transfusion incidents reported annually . Immediate incidents observed within 8 days after transfusion account for 85% of the reports . A cause cannot be identified in 41% of these, usually concerning minor clinical incidents with transient fever and/or shivers . An allergic reaction is described in 31% of transfusion reactions . Immunological conflicts account for 18% and bacteria associated transfusion reactions for 6% . The importance of bacteria associated transfusion reactions, the first identified cause of death associated with transfusion is one of the findings of haemovigilance . Improvement in the haemovigilance systems aims at obtaining better descriptions of transfusion incidents, standardisation of severity and imputability assessment and definitions of denominators such as the actual number of recipients . Delayed incidents will ultimately provide a true vision of post transfusion immunisation and infection The improvement of haemovigilance now considered as part of transfusion medicine practice is a continuous process.

Vox Sang, 1998, 74 Suppl 2, 29 - 64
Insights into the structure and function of membrane polypeptides carrying blood group antigens; Cartron JP et al.; In recent years, advances in biochemistry and molecular genetics have contributed to establishing the structure of the genes and proteins from most of the 23 blood group systems presently known . Current investigations are focusing on genetic polymorphism analysis, tissue-specific expression, biological properties and structure-function relationships . On the basis of this information, the blood group antigens were tentatively classified into five functional categories: (i) transporters and channels, (ii) receptors for exogenous ligands, viruses, bacteria and parasites, (iii) adhesion molecules, (iv) enzymes and, (v) structural proteins . This review will focus on selected blood groups systems (RH, JK, FY, LU, LW, KEL and XK) which are representative of these classes of molecules, in order to illustrate how these studies may bring new information on common and variant phenotypes and for understanding both the mechanisms of tissue specific expression and the potential function of these antigens, particularly those expressed in nonerythroid lineage.

Arkh Patol, 1998 May-Jun, 60(3), 63 - 7
{Ulcer disease: new facts--new issues}; Lapina TL; Involvement of Helicobacter pylori in pathogenesis of ulcer, the role of inflammation induced by the bacteria and possible mechanisms of hypergastrinemia are considered . The results of therapy directed to eradication of H . pylori from the clinical and pathogenetic point of view are presented . The role of H . pylori in asymptomatic gastritis and in gastric and duodenal ulcer is discussed . The information on genetic variability of H . pylori and its strains with different pathogenicity distinguished on the basis of genes encoding vacuolising cytotoxin and cytotoxin-associated protein is provided.

J Med Entomol, 1998 Jul, 35(4), 514 - 20
Interaction of entomopathogenic nematodes (Steinernematidae) with selected species of ixodid ticks (Acari: Ixodidae); Kocan KM et al.; Entomopathogenic nematodes, currently used for biological control of various insect pests, were tested for their ability to penetrate and kill replete females of several species of ticks including Dermacentor variabilis (Say), Rhipicephalus sanguineus (Latreille), Amblyomma maculatum Koch, and A . cajennense (F.) . These species were found to be susceptible to the entomopathogenic nematodes, Steinernema feltiae (Filipjev) or S . riobravus (Cabanillas & Poinar), shown in previous studies in our laboratory to be attracted to and kill replete A . americanum . S . riobravus killed D . variabilis (96%), R . sanguineus (89%), A . maculatum (24%), and A . cajennense (88%), and S . feltiae killed D . variabilis (91%) and R . sanguineus (71%) . Of the ticks that survived mean egg mass weights were significantly lower than those of the unexposed controls . When nematode-exposed ticks were examined with light microscopy, nematodes were found to have entered ticks but did not multiply or produce subsequent generations of infective juveniles . The nematodes were separated from surrounding tissues by a clear space, suggesting that they produced protective compounds . Bacteria, thought to be symbiotes released from the nematodes, multiplied initially in the hemocoel of the tick and subsequently were found throughout the degenerating tick tissues . These bacteria eventually filled the tick and appeared to be the cause of tick death . Nematode guts were filled with the bacteria, suggesting that the bacteria were a food source . When ticks were exposed to nematodes while feeding on cattle, partially engorged females were most susceptible to the nematodes . Tick mortality and reduced egg production resulted when the ticks had fed 6 and 9 d before nematode exposure but not when ticks were exposed after 3 d of feeding . Exposure of feeding female ticks demonstrated that the nematodes were able to penetrate tick orifices other than via the hypostome, which was embedded in the bovine epidermis for the duration of the feeding process.

Mol Microbiol, 1998 Jul, 29(1), 27 - 38
Molecular and functional analysis of the lipopolysaccharide biosynthesis locus wlb from Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica; Allen AG et al.; The Bordetella pertussis wlb locus (wlbpe, formerly bpl) is required for the biosynthesis of a trisaccharide that, when attached to the B . pertussis lipopolysaccharide (LPS) core (band B), generates band A LPS . The equivalent loci in Bordetella bronchiseptica (wlbbr) and Bordetella parapertussis (wlbpa) were identified and cloned . The wlbbr and wlbpa loci differ from wlbpe in that they lack the insertion sequence that defines the right-hand terminus of wlbpe . Deletion of 12 kb of DNA containing the whole wlb locus (delta wlb) by allelic exchange in each of the three bordetellae had no effect on band B biosynthesis, whereas band A biosynthesis was prevented in B . pertussis and B . bronchiseptica . In B . bronchiseptica and B . parapertussis, delta wlb mutants also lacked O-antigen . Reintroduction of the wlbpe or wlbbr loci on a shuttle vector into the three delta wlb mutants restored the wild-type LPS phenotype in the B . pertussis and B . bronchiseptica mutants . In the case of B . parapertussis, which normally does not synthesize an apparent band A structure, introduction of the wlbpe or wlbbr loci now enabled the generation of band A . This suggests that the attachment point for band A trisaccharide on the LPS core is present in B . parapertussis, and further suggests that the wild-type wlbpa locus is not fully functional . Introduction of the wlbpa locus into the delta wlbpe, delta wlbbr and delta wlbpa mutants had interesting consequences . The B . bronchiseptica and B . parapertussis recipients were now able to biosynthesize O-antigen, but no band A was generated . In the B . pertussis recipient, a truncated band A was expressed consistent with a mutation in the wlbH gene, but on Western blotting the expression of a small amount of full-length band A was also seen . Evidence that the wlbHpa protein is not fully functional was provided by the failure of the wlbpa locus to fully complement a B . pertussis wlbH (delta wlbHpe) mutant . This was supported by DNA sequence data showing that a single amino acid, conserved between homologous proteins from a range of bacteria, is altered in the B . parapertussis WlbH protein.

Arch Pathol Lab Med, 1998 Aug, 122(8), 732 - 6
A new triple stain for Helicobacter pylori suitable for the autostainer: carbol fuchsin/Alcian blue/hematoxylin-eosin; El-Zimaity HM et al.; OBJECTIVE: To develop an inexpensive stain to simultaneously visualize gastric morphology and Helicobacter pylori . METHODS: Gastric biopsies were stained with Genta stain using manual methods, and with carbol fuchsin/Alcian blue/hematoxylin-eosin using an automatic slide stainer (Sakura DRS-601) . Slides were then coded and interpreted by 2 pathologists . Helicobacter pylori was scored using a visual scale (0 {none} to 5 {maximum}) . RESULTS: One hundred slides were scored; H pylori was present in 64% . Carbol fuchsin/Alcian blue/hematoxylin-eosin stain gave excellent demonstration of gastric morphology . All positive cases (score > or =2) were correctly interpreted . Thirty-six slides had a score of 1 (< or =2 bacteria per entire slide) . Of these, 10 were scored negative by Genta stain and 12 were scored negative by the carbol fuchsin/Alcian blue/hematoxylin-eosin stain (P = not significant) . Hematoxylin-eosin was significantly less accurate than either of the other 2 stains (P < .02) . CONCLUSION: The carbol fuchsin/Alcian blue/hematoxylin-eosin (El-Zimaity) stain is an economical stain suitable for simultaneous visualization of H pylori infection and gastric morphology.

Pathol Int, 1998 Jul, 48(7), 507 - 11
Gastrospirillum hominis and Helicobacter pylori infection in Thai individuals: comparison of histopathological changes of gastric mucosa; Yali Z et al.; The presence of Helicobacter pylori (H . pylori) in the stomach is closely associated with histological signs of chronic active gastritis and peptic ulcer . Another spiral organism named Gastrospirillum hominis (G . hominis) has led to further interest in the bacterial pathogenesis of gastritis . Due to the low prevalence of G . hominis, it is difficult to evaluate its biological behavior . Recently 16 cases of G . hominis-associated gastritis were found in 257 Thai individuals, which made it possible to study the biological characteristics of G . hominis and its relationship with gastric mucosal inflammation . The results showed that H . pylori and G . hominis could be easily observed in the lower third of the mucous layer and in the mucosa of the gastric pits by means of toluidine blue staining . Both bacteria immunostained positive . Helicobacter pylori were usually in the shape of curved bacillary while G . hominis often appeared in spiral configuration . In 257 cases of Thai subjects, 169 cases were found to be H . pylori positive, the detection rate was 65.7%, and 16 cases were G . hominis positive, with a 6.2% detection rate . In G . hominis infection, 43.6% of cases had normal gastric mucosa . Superficial, erosive and atrophic gastritis cases were 13.2, 10.9 and 12.5%, respectively . Mucosal inflammation was usually severe in H . pylori, but neutrophil polymorph infiltration was often mild and focal in G . hominis infection . Although no G . hominis infection with carcinoma was shown in our cases, the occurrence of mucosal atrophy, metaplasia and dysplasia was higher in both bacterial infections compared with H . pylori- and G . hominis-negative cases . It is suggested that G . hominis may be partly responsible for the mucosal inflammation and some malignant-associated lesions.

Aliment Pharmacol Ther, 1998 Feb, 12 Suppl 1, 61 - 71
Review article: Pathogenesis of the transformation from gastritis to malignancy; Sipponen P et al.; Helicobacter pylori acquisition is the main cause of chronic gastritis in humans . In up to half of the infected subjects, chronic gastritis progresses to atrophic gastritis and intestinal metaplasia . During this course, various mechanisms are triggered that may contribute to the pathogenesis of gastric cancer . Such mechanisms include the inflammation-related cascades of cytokine and free radical reactions, up- and downregulation of growth factors and their receptors, and the atrophy-related impairment of acid output and intraluminal acidity . An array of other factors may also have become significant including overgrowth of bacteria other than H . pylori in the hypochlorhydric or achlorhydric stomach, a high dietary consumption of salt, nitrate, or nitrite, smoking, deficiency of vitamins or micronutrients, influence of sex hormones, or an inherited liability of the dividing epithelial cells to gene errors . These factors may vary in effect between populations and individuals but, if active, may affect the cell genome which may further influence the course and progression of chronic gastritis, and can finally result in overt gastric neoplasia . The molecular biology of gastric cancer has revealed a spectrum of gene errors which vary in type and extent between different histological types of cancer, and between individual cases . There now is evidence that the intestinal metaplasia or the gastric epithelium in atrophic gastritis reveal signs of abnormal expression of various regulatory genes well before the appearance of gastric neoplasia . It is possible that the mechanisms leading to mutation of the genes in epithelial cells are triggered very early in the H . pylori gastritis cascade, and that atrophic gastritis and intestinal metaplasia result from these processes.

J Chromatogr A, 1998 Jul 17, 813(2), 285 - 97
Determination of arylphenoxypropionic herbicides in water by liquid chromatography-electrospray mass spectrometry; D'Ascenzo G et al.; A very sensitive and specific analytical procedure for determining arylphenoxypropionic herbicides in aqueous environmental samples, using pneumatically assisted electrospray (ESI) liquid chromatography-mass spectrometry (LC-MS) is presented . Arylphenoxypropionic acids are a new class of herbicides used for the selective removal of most grass species from any nongrass crop . These herbicides are commercialized as herbicide esters . It has been shown that the ester derivatives undergo fast hydrolysis in the presence of vegetable tissues and soil bacteria, yielding the corresponding free acid . The analytical procedure involves passing 1l of surface or ground water and 2l of drinking-water samples, through a 0.5-g graphitized carbon black (GCB) extraction cartridge . A conventional 4.6-mm I.D . reversed-phase LC C18, operating with a 1 ml/min mobile phase flow-rate, was used for chromatographing the analytes . A flow of 200 microliters/min of the column effluent was diverted to the ESI source . The ESI source was operated in positive-ion mode for neutral pesticides and in negative-ion mode for acid pesticides . For ion-signal optimization, the effect of the concentration of the acid in the mobile phase on the response of the ESI-MS detector was investigated . By evaluating the specificity and sensitivity of the method, the effects of varying the orifice plate voltage on the production of the diagnostic fragment and the response of the MS detector were also investigated . For the analyte considered, the response of the mass detector was linearly related to the amount of the analyte injected between 1 and 200 ng . In all cases, recoveries of the analytes were better than 91% . The limit of detection (signal-to-noise ratio = 3) of the method for the pesticides considered in drinking water samples was estimated to be about 3-10 ng/l.

J Invest Dermatol, 1998 Aug, 111(2), 183 - 8
DNA immunization targeting the skin: molecular control of adaptive immunity; Tuting T et al.; DNA-based immunization represents a novel approach for vaccine development . Recombinant DNA techniques are used to clone DNA sequences encoding antigens of choice into eukaryotic expression plasmids, which are readily and economically amplified in bacteria and recovered with a high degree of purity . For immunization, plasmid DNA is either coated onto microscopic gold particles and bombarded into skin using a gene gun or injected into skin or muscle . Expression of administered genes results in the induction of humoral and cellular immune responses against the encoded antigen . DNA immunization is capable of inducing protective immunity in a number of animal models of infectious disease and cancer . Recent studies suggest that antigen-specific cytotoxic T lymphocyte induction occurs through the presentation of appropriate peptides in the context of major histocompatibility complex molecules on bone marrow-derived professional antigen presenting cells . Following DNA inoculation into the skin, Langerhans cells and/or dermal dendritic cells are believed to acquire the newly synthesized antigen, either through direct transfection or via antigen uptake from transfected keratinocytes, and migrate to regional lymph nodes where they stimulate primary T cell responses . The nature of the immune response depends on the route, method, and timing of DNA delivery and can also be influenced by co-delivery of plasmids encoding immunomodulating cytokines like IFN-alpha, IL-2, or IL-12 and costimulatory molecules like B7-1 . While many aspects of the biology of cutaneous DNA immunization remain unknown, the skin appears to offer unique potential as a target for DNA-based immunization.

Mol Biol Rep, 1998 Jul, 25(3), 183 - 8
Independent patterns of expression of two alternative sigma factors, sigB and sigC, of the myxobacterium Stigmatella aurantiaca during development; Coudart MP; The transcription of many spatially and temporally controlled developmental genes is required for cellular differentiation of the myxobacterium Stigmatella aurantiaca . The expression patterns of the sigma factor gene sigB and of a novel alternative sigma factor gene sigC have been studied during development of Stigmatella aurantiaca . They are expressed at different stages of development . sigB is expressed from the very beginning of fruiting body formation to the sporulation step, while sigC expression takes place later, from the stalk formation to the sporulation step . Neither sigB nor sigC are expressed during heat shock . A sigB mutant and a sigC mutant have been constructed by gene replacement . Their analysis has shown that sigB and sigC expression are independent from each other.

J Dent, 1998 Jul-Aug, 26(5-6), 409 - 16
Pulp reactions to restoration of experimentally induced crown fractures; Robertson A et al.; OBJECTIVES: Reattachment of the avulsed enamel-dentine coronal fragment to the remaining tooth structure has become an accepted clinical alternative to a resin composite build-up for the restoration of crown fractured teeth . Since little knowledge exists as to the pulpal response to this procedure, this study was designed to observe the condition of the pulp following experimentally induced crown fracture and restoration in monkeys . METHODS: Experiments were conducted in eight young green Vervet monkeys (Cercopithecus aethiops) . In all, 64 fractured incisors were investigated . Light microscopic examination of pulp tissue specimens was carried out after 3 months of observation . RESULTS: The evaluation was restricted to specimens having a fracture plane within 2 mm of the pulp and no pulpal exposure . In general, pulp tissue was well preserved irrespective of the restorative procedure . Even if the restoration or the bonded tooth fragment had been lost during the follow-up period, the pulp generally remained in good condition . Inflammatory infiltrates where seen in only a few specimens and then as clusters of mononuclear leukocytes . Hard tissue repair was frequently observed and displayed various configurations from isolated hard tissue deposits to areas of extensive hard tissue repair in the coronal portion of the pulp . Pronounced hard tissue repair and occurrence of inflammatory cell infiltrates correlated with the presence of stainable bacteria on the fractured dentine surface . CONCLUSIONS: In the absence of direct exposure, reparative dentine is a frequent feature of the pulp's response to crown fracture and restoration with composite or reattachment of the crown fragment with dentine bonding . These restorative procedures appear to ensure continued function of the underlying pulp.

What Is Anthrax?, What Is Yeast?, What Is Molecular Biology?, What Is Cell Biology?, What Is Rhizobia?, n, Bacterium, c, Microorganisms, n, Bacteria, o, Microbe, a, Microbiology, e, Bacillus, i, Pseudomonas aeruginosa, i, Shigella, s, Yeasts, a, Enterococci, n, Neisseria, e, Water treatment, i, Cell cultures, i, Corynebacter, c, Microorganism, e, Yeasts, e, Enterococci, i, Microbial, i, Microbial, c, Micrococci, r, Phage, n, Fermentations, e, Microorganisms, a, Candida albicans, i, Escherichia coli, r, Serratia

Scientific Publications - Work Done by Microbiology Reader Bioscreen C
Agricultural Microbiology Anaerobic Microbiology Antimicrobial Susceptibility Artificial Atmosphere Bioassay of Antibiotics Biofilm Microbiology Bioreactor Technology Biotechnology Cell Biology Clinical Microbiology Environmental Microbiology Experiments with Yeast	Fermentation Food Microbiology Functional Genomics Gene Technology Growth Media Development Growth Rate and Lag Time Industrial Microbiology Medical/Pharmaceutical Field Microbiological Assay Microbiological Research Microbiology of Cosmetics go to a specific theme...	Military Microbiology Molecular Microbiology Mutagenicity and Genotoxicity Oral Microbiology Patents Postantibiotic Studies Soil Microbiology Spore Microbiology Veterinary Microbiology Waste/Wastewater Treatment Water Microbiology Wine Microbiology

� 2005 Transgalactic Ltd (manufacturer of Bioscreen C software) | Privacy Statement | P.O. Box 1393, 00101 Helsinki, Finland, phone: +358 9 85172920, fax: +358 9 8749481, e-mail: microbiology@bionewsonline.com

Last modified: May 25, 2005