Microorganisms

Appl Environ Microbiol, 2000 Mar, 66(3), 1050 - 6
Reduction of Fe(III), Mn(IV), and toxic metals at 100 degrees C by Pyrobaculum islandicum; Kashefi K et al.; It has recently been noted that a diversity of hyperthermophilic microorganisms have the ability to reduce Fe(III) with hydrogen as the electron donor, but the reduction of Fe(III) or other metals by these organisms has not been previously examined in detail . When Pyrobaculum islandicum was grown at 100 degrees C in a medium with hydrogen as the electron donor and Fe(III)-citrate as the electron acceptor, the increase in cell numbers of P . islandicum per mole of Fe(III) reduced was found to be ca . 10-fold higher than previously reported . Poorly crystalline Fe(III) oxide could also serve as the electron acceptor for growth on hydrogen . The stoichiometry of hydrogen uptake and Fe(III) oxide reduction was consistent with the oxidation of 1 mol of hydrogen resulting in the reduction of 2 mol of Fe(III) . The poorly crystalline Fe(III) oxide was reduced to extracellular magnetite . P . islandicum could not effectively reduce the crystalline Fe(III) oxide minerals goethite and hematite . In addition to using hydrogen as an electron donor for Fe(III) reduction, P . islandicum grew via Fe(III) reduction in media in which peptone and yeast extract served as potential electron donors . The closely related species P . aerophilum grew via Fe(III) reduction in a similar complex medium . Cell suspensions of P . islandicum reduced the following metals with hydrogen as the electron donor: U(VI), Tc(VII), Cr(VI), Co(III), and Mn(IV) . The reduction of these metals was dependent upon the presence of cells and hydrogen . The metalloids arsenate and selenate were not reduced . U(VI) was reduced to the insoluble U(IV) mineral uraninite, which was extracellular . Tc(VII) was reduced to insoluble Tc(IV) or Tc(V) . Cr(VI) was reduced to the less toxic, less soluble Cr(III) . Co(III) was reduced to Co(II) . Mn(IV) was reduced to Mn(II) with the formation of manganese carbonate . These results demonstrate that biological reduction may contribute to the speciation of metals in hydrothermal environments and could account for such phenomena as magnetite accumulation and the formation of uranium deposits at ca . 100 degrees C . Reduction of toxic metals with hyperthermophilic microorganisms or their enzymes might be applied to the remediation of metal-contaminated waters or waste streams.

Can J Microbiol, 2000 Jan, 46(1), 72 - 80
Growth kinetics of Escherichia coli with galactose and several other sugars in carbon-limited chemostat culture; Lendenmann U et al.; Kinetic models for microbial growth describe the specific growth rate (mu) as a function of the concentration of the growth-limiting nutrient (s) and a set of parameters . A typical example is the model proposed by Monod, where mu is related to s using substrate affinity (Ks) and the maximum specific growth rate (mu max) . The preferred method to determine such parameters is to grow microorganisms in continuous culture and to measure the concentration of the growth-limiting substrate as a function of the dilution rate . However, owing to the lack of analytical methods to quantify sugars in the microgram per litre range, it has not been possible to investigate the growth kinetics of Escherichia coli in chemostat culture . Using an HPLC method able to determine steady-state concentrations of reducing sugars, we previously have shown that the Monod model adequately describes glucose-limited growth of E . coli ML30 . This has not been confirmed for any other sugar . Therefore, we carried out a similar study with galactose and found steady-state concentrations between 18 and 840 micrograms.L-1 for dilution rates between 0.2 and 0.8.h-1, respectively . With these data the parameters of several models giving the specific growth rate as a function of the substrate concentration were estimated by nonlinear parameter estimation, and subsequently, the models were evaluated statistically . From all equations tested, the Monod model described the data best . The parameters for galactose utilisation were mu max = 0.75.h-1 and Ks = 67 micrograms.L-1 . The results indicated that accurate Ks values can be estimated from a limited set of steady-state data when employing mu max measured during balanced growth in batch culture . This simplified procedure was applied for maltose, ribose, and fructose . For growth of E . coli with these sugars, mu max and Ks were for maltose 0.87.h-1, 100 micrograms.L-1; for ribose 0.57.h-1, 132 micrograms.L-1, and for fructose 0.70.h-1, 125 micrograms.L-1.

J Clin Microbiol, 2000 Mar, 38(3), 1085 - 93
Touchdown enzyme time release-PCR for detection and identification of Chlamydia trachomatis, C . pneumoniae, and C . psittaci using the 16S and 16S-23S spacer rRNA genes; Madico G et al.; Three touchdown enzyme time release (TETR)-PCR assays were used to amplify different DNA sequences in the variable regions of the 16S and 16S-23S spacer rRNA genes specific for Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci as improved tests for sensitive diagnosis and rapid species differentiation . The TETR-PCR protocol used 60 cycles of amplification, which provided improved analytical sensitivity (0.004 to 0.063 inclusion-forming unit of Chlamydia species per PCR) . The sensitivity of TETR-PCR with primer set CTR 70-CTR 71 was 96.7%, and the specificity was 99.6%, compared to those of the AMPLICOR PCR for the detection of C . trachomatis in vaginal swab samples . TETR-PCR for C . pneumoniae with primer set CPN 90-CPN 91 was 90% sensitive and 93.3% specific compared with a nested PCR with primer set CP1/2-CPC/D for clinical respiratory samples . TETR-PCR for C . psittaci with primer set CPS 100-CPS 101 showed substantial agreement with cell culturing (kappa, 0.78) for animal tissue samples . Primer sets were then combined into a single multiplex TETR-PCR test . The respective 315-, 195-, and 111-bp DNA target products were precisely amplified when DNA from each of the respective Chlamydia species or combinations of them was used . Multiplex chlamydia TETR-PCR correctly identified one strain of each of the 15 serovars of C . trachomatis, 22 isolates of C . pneumoniae, and 20 isolates of C . psittaci . The primer sets were specific for each species . No target products were amplified when DNA from C . pecorum or a variety of other microorganisms was tested for specificity . TETR-PCR with primers selected for specific sequences in the 16S and 16S-23S spacer rRNA genes is a valuable test that could be used either with individual primers or in a multiplex assay for the identification and differentiation of Chlamydia species from culture isolates or for the detection of chlamydiae in clinical samples.

Parassitologia, 1999 Sep, 41(1-3), 397 - 402
Pre-erythrocytic malaria vaccine: mechanisms of protective immunity and human vaccine trials; Nardin E et al.; In order to provide a rational basis for the development of a pre-erythrocytic malaria vaccine we have aimed at: (a) elucidating the mechanisms of protection, and (b) identifying vaccine formulations that best elicit protection in experimental animals and humans . Based on earlier successful immunization of experimental animals with irradiated sporozoites, human volunteers were exposed to the bites of large numbers of Plasmodium falciparum or P . vivax infected irradiated mosquitoes . The result of this vaccine trial demonstrated for the first time that a pre-erythrocytic vaccine, administered to humans, can result in their complete resistance to malaria infection . However, since infected irradiated mosquitoes are unavailable for large scale vaccination, the alternative is to develop subunit vaccines . The human trials using irradiated sporozoites provided valuable information on the human immune responses to pre-erythrocytic stages and studies on mice an excellent experimental model to characterize protective immune mechanisms . The circumsporozoite protein, the first pre-erythrocytic antigen identified, is present in all malaria species, displaying a similar structure, with a central region of repeats, and two conserved regions, essential for parasite development . Most pre-erythrocytic vaccine candidates are based on the CS protein, expressed in various cell lines, microorganisms, and recently the corresponding DNA . We and others have identified CS-specific B and T cell epitopes, recognized by the rodent and human immune systems, and used them for the development of synthetic vaccines . We used synthetic peptide vaccines, multiple antigen peptides and polyoximes, for immunization, first in experimental animals, and recently in two human safety and immunogenicity trials . We also report here on our work on T cell mediated immunity, particularly the protection of mice immunized with viral vectors expressing CS-specific cytotoxic CD8+ T cell epitopes, and the striking booster effect of recombinant vaccinia virus . To what degree CD8+ T cells, and/or other T cells specific for sporozoites and/or liver stage epitopes, contribute to pre-erythrocytic protective immunity in humans, remains to be determined.

Parassitologia, 1999 Sep, 41(1-3), 159 - 62
Transmission stages of Plasmodium: does the parasite use the one same signal, provided both by the host and the vector, for gametocytogenesis and sporozoite maturation?
Milon G, David PH.
Among the microorganisms that strictly depend upon other organisms (hosts or vectors) for achieving their life cycle, protozoan and metazoan parasites have been often primarily distinguished through the major pathogenic processes they could induce . A variety of different mechanisms linked to parasitism can indeed systemically (e.g . Plasmodium falciparum) or locally (e.g . Toxoplasma gondii) induce important alterations of tissue homeostasis . But more than obvious pathogenicity, it is the capacity to be transmitted that is essential for parasite survival and there is increasing evidence that certain parasites can achieve their life cycle to the point of transmission in the absence of clinically detectable processes . For this, constitutive microenvironments of the host or vector can be exploited . Moreover, parasites are sometimes able to highjack effectors of the host's immune response towards conditioning the microenvironments which are permissive to differentiation of transmissible developmental stages . Based on a few examples taken from studies on the transmission stages of Leishmania, Toxoplasma and Plasmodium, we have here attempted to formulate a few hypothesis on the biology of the transmission stages of P . falciparum, i.e . on gametocytogenesis and sporozoite maturation . As discussants, we may have been somewhat dwarfed by issues evoked by the organizers of this meeting in the title of the session, i.e . 'Vector-parasite-man interactions'!.. . In reaction, we may have taken refuge in somewhat over-selective comments, biased by the objects of our personal research....

J Food Prot, 2000 Feb, 63(2), 174 - 8
Attempts to isolate Helicobacter from cattle and survival of Helicobacter pylori in beef products; Stevenson TH et al.; This study focused on important factors related to the potential of cattle and beef products to transmit Helicobacter pylori to humans . Mucosal samples were collected from the rumen and abomasum of 105 cattle and were plated on a selective medium to isolate Helicobacter spp.; none of the samples examined contained these bacteria . Studies were also conducted to determine how long H . pylori survives in refrigerated or frozen ground beef; results indicated that the microorganism dies rapidly in ground beef, whether refrigerated or frozen . Packaging in vacuum or air had little effect on survival of the organism . The number of H . pylori decreased in refrigerated samples from 3.3 log10 CFU/g on day 0 to 1.4 log10 CFU/g on day 6 . H . pylori died even more rapidly when frozen, decreasing from 3.3 log10 CFU/g on day 0 to 0.5 log10 CFU/g on day 6 . Retail beef cuts (n = 20) were also examined for the presence of H . pylori by direct plating on a selective medium and by incubation in an enriched broth followed by plating on a selective medium . None of the retail samples contained H . pylori . This research suggests that transmission of H . pylori from beef and beef products is not a primary factor in the high prevalence of this bacterium in humans.

J Periodontol, 2000 Jan, 71(1), 14 - 21
Persistence patterns of Porphyromonas gingivalis, Prevotella intermedia/nigrescens, and Actinobacillus actinomyetemcomitans after mechanical therapy of periodontal disease; Mombelli A et al.; BACKGROUND: The aim of this study was to determine the distribution patterns of Porphyromonas gingivalis, Prevotella intermedia/nigrescens, and Actinobacillus actinomycetemcomitans in periodontitis patients after standard mechanical periodontal therapy, and to determine factors increasing the odds to detect these target organisms in treated sites . METHODS: Eight hundred fifty-two (852) separate subgingival microbial samples were taken from the mesial and distal aspects of every tooth in 17 patients . Target organisms were identified culturally . RESULTS: The 3 microorganisms showed different persistence patterns: P . gingivalis was detected in a high percentage of subjects (59%), but in a low proportion of sites (5.4%) . P . intermedia/nigrescens was detected in all subjects except one, and in 40.6% of the tested sites . Only 5 subjects were A . actinomycetemcomitans positive, but 2 of them showed a very high number of positive sites (44% and 75%, respectively) . A highly significant relationship was found between a subject's tendency to bleed upon sampling and the number of P . intermedia/nigrescens-positive sites . A significant portion of the variation in frequency of persisting P . gingivalis could be explained by the frequency of persisting pockets deeper than 4 mm . No similar relationship could be established between clinical parameters and A . actinomycetemcomitans . On a site level, the odds of detecting P . gingivalis increased by a factor of 2.47 (P= 0.0001) for every millimeter of residual probing depth; the odds of detecting P . intermedia/nigrescens increased by a factor of 1.84 (P= 0.0001) . CONCLUSIONS: If, after standard mechanical periodontal therapy, a large number of sites continue to bleed, one may expect an increased number of sites positive for P . intermedia/ nigrescens . If many deep pockets persist, a greater number of P . gingivalis-positive sites can be expected.

J Physiol Pharmacol, 1999 Dec, 50(5), 735 - 42
The role of Helicobacter pylori in cardiovascular and cerebrovascular diseases; Gasbarrini A et al.; Classical risk factors for cardiovascular and cerebrovascular diseases do not fully coincide with the prevalence of these conditions . Emerging evidences show that new factors may be predisposing for the development of ischemic events . It has been demonstrated that atherosclerosis has a strong inflammatory background; such state of chronic inflammation may be related to the presence of persistent infectious agent . Helicobacter pylori (H . pylori), among other microorganisms, has been extensively investigated for its possible role . Many molecular mechanisms have been hypothesized to explain its eventual action . Epidemiological studies do not exclude a correlation between the infection and cardiovascular and cerebrovascular diseases . Many confounding factors, however, make difficult a definitive evaluation of the huge number of data present in the literature . Moreover, various therapeutic studies have been attempted to show if antibiotic treatment improves prognosis in patients affected by ischemic heart disease . Still, none of these trials focused specifically on the effects of H . pylori eradication on the clinical progression of vascular lesions.

Trends Biochem Sci, 2000 Mar, 25(3), 138 - 43
A novel FeS cluster in Fe-only hydrogenases; Nicolet Y et al.; Many microorganisms can use molecular hydrogen as a source of electrons or generate it by reducing protons . These reactions are catalysed by metalloenzymes of two types: NiFe and Fe-only hydrogenases . Here, we review recent structural results concerning the latter, putting special emphasis on the characteristics of the active site.

Proc Natl Acad Sci U S A, 2000 Mar 14, 97(6), 2486 - 90
Biosynthesis of terpenoids: YgbB protein converts 4-diphosphocytidyl-2C-methyl-D-erythritol 2-phosphate to 2C-methyl-D-erythritol 2,4-cyclodiphosphate; Herz S et al.; In many microorganisms, the putative orthologs of the Escherichia coli ygbB gene are tightly linked or fused to putative orthologs of ygbP, which has been shown earlier to be involved in terpenoid biosynthesis . The ygbB gene of E . coli was expressed in a recombinant E . coli strain and was shown to direct the synthesis of a soluble, 17-kDa polypeptide . The recombinant protein was found to convert 4-diphosphocytidyl-2C-methyl-D-erythritol 2-phosphate into 2C-methyl-D-erythritol 2,4-cyclodiphosphate and CMP . The structure of the reaction product was established by NMR spectroscopy using (13)C-labeled substrate samples . The enzyme-catalyzed reaction requires Mn(2+) or Mg(2+) but no other cofactors . Radioactivity from {2-(14)C}2C-methyl-D-erythritol 2,4-cyclodiphosphate was diverted efficiently to carotenoids by isolated chromoplasts from Capsicum annuum and, thus, was established as an intermediate in the deoxyxylulose phosphate pathway of isoprenoid biosynthesis . YgbB protein also was found to convert 4-diphosphocytidyl-2C-methyl-D-erythritol into 2C-methyl-D-erythritol 3,4-cyclophosphate . This compound does not serve as substrate for the formation of carotenoids by isolated chromoplasts and is assumed to be an in vitro product without metabolic relevance.

Biochem Biophys Res Commun, 2000 Mar 5, 269(1), 290 - 5
Identification of benzodiazepines in Artemisia dracunculus and Solanum tuberosum rationalizing their endogenous formation in plant tissue; Kavvadias D et al.; Sterile cultivated plant cell tissues and cell regenerates of several species were tested for their binding affinity to the central human benzodiazepine receptor . Binding activity was found in extracts of Artemisia dracunculus cell tissue (IC(50) = 7 microg/ml) and, to a lesser extent, in plant regenerates of potato herb (Solanum tuberosum) . Preparative HPLC led to the isolation of fractions with a significant displacing potency in the benzodiazepine receptor binding assay . Using on-line HPLC-electrospray-tandem mass spectrometry (HPLC-ESI-MS/MS) in the "selected reaction monitoring" (SRM) mode, delorazepam and temazepam were found in amounts of about 100 to 200 ng/g cell tissue of Artemisia dracunculus, whereas sterile potato herb contained temazepam and diazepam ranging approximately from 70 to 450 ng/g cell tissue . It is the first report on the endogenous formation of benzodiazepines by plant cells, as any interaction of microorganisms and environmental factors was excluded .

Stomatologiia (Mosk), 2000, 79(1), 13 - 6
{The evaluation of periodontal status by the chemical composition of the oral media}; Volozhin AI et al.; Twelve patients aged 21-38 years with gingivitis and periodontitis and 9 subjects with intact periodontium were examined . Air from the oral cavity was collected with a special device, liquid samples were collected by gargling with sterile water . Chemical composition of the air and washings was analyzed by chromato-mass-spectrometry, gas adsorption and gas liquid chromatography . Inflammation of periodontal tissues was associated with a sharp increase in the oral air concentration of methylethylketone . The concentrations of isovaleric, n-valeric, and n-enanthic aldehydes increased appreciably . Ethanol predominated over n-butyl alcohol . The levels of dimethylsulfide and isoprene increased several times . In the washings from the oral cavity, the content of microorganism's vital activity products (fatty acids) was increased . Possible metabolic mechanisms of the detected shifts are discussed.

J Immunol, 2000 Mar 1, 164(5), 2610 - 8
Purification and characterization of two mannan-binding lectins from mouse serum; Hansen S et al.; Mannan-binding lectin (MBL) is a serum protein that activates the complement system after binding to glycoconjugates found on the surface of microorganisms . By molecular cloning two forms of MBL have been identified in the mouse (mMBL-A and mMBL-C), but only mMBL-A has been purified and characterized at the protein level . MBL-C has been termed the liver form of MBL . The present report describes the purification and characterization of mMBL-A and mMBL-C from serum . The two forms of mMBL could be separated both by ion-exchange and carbohydrate-affinity chromatography . The initial identification by immunochemical technique was confirmed by N-terminal amino-acid sequencing . Both proteins give bands corresponding to polypeptide chains of 28 kDa on SDS-PAGE in the reduced state, but mMBL-A migrated more rapidly than mMBL-C in acid/urea-PAGE, in accordance with the calculated pIs . Both forms mediated activation of complement component C4 in mannan-coated microtiter wells . MBL-A showed a higher affinity for d -glucose and alpha-methyl-d -glucose then did MBL-C . Serum concentrations of mMBL-A in laboratory strains and wild mice were found to vary from 5 to 80 microg/ml, with wild mice tending to show higher levels than laboratory strains.

J Cutan Med Surg, 2000 Jan, 4(1), 30 - 5
Lichen planopilaris-like changes arising within an epidermal nevus: does this case suggest clues to the etiology of lichen planopilaris?
Smith KJ, Crittenden J, Skelton H.
BACKGROUND: Lichen planopilaris shows a perifollicular lymphocytic infiltrate at the level of infundibulum and the isthmus of the hair bulge resulting in necrotic changes within keratinocytes and eventually hair loss . OBJECTIVE: We present a 14-year-old black male with a history of a raised epidermal lesion on the scalp that was present at birth . Over the past few years, the patient developed gradual hair loss and increased verrucous changes of the skin within the original lesion . Histologic sections of the area showed features consistent with an epidermal nevus peripherally, with a central area showing some features characteristic of those seen in lichen planopilaris . In addition, there was marked hyperkeratosis with increased yeast and bacteria within the follicles . CONCLUSIONS: Initiating factors in lichen planopilaris are not well defined . Overgrowth of microorganisms with hyperkeratosis results in factors that disrupt the immune privilege of the hair follicle, leading to an immunologic reaction that is limited to the follicle and spares surrounding eccrine structures . This case suggests possible mechanisms involved in the induction of lichen planopilaris.

Gene, 2000 Feb 22, 244(1-2), 47 - 54
Mammalian genomes contain active recombinase recognition sites; Thyagarajan B et al.; Recombinases derived from microorganisms mediate efficient site-specific recombination . For example, the Cre recombinase from bacteriophage P1 efficiently carries out recombination at its loxP target sites . While this enzyme can function in mammalian cells, the 34bp loxP site is expected to be absent from mammalian genomes . We have discovered that sequences from the human and mouse genomes surprisingly divergent from loxP can support Cre-mediated recombination at up to 100% of the efficiency of the native loxP site in bacterial assays . Transient assays in human cells demonstrate that such pseudo-lox sites also support Cre-mediated integration and excision in the human cell environment . Pseudo sites for Cre and other recombinases may be useful for site-specific insertion of exogenous genes into mammalian genomes during gene therapy and other genetic engineering processes.

Gen Dent, 1999 Nov-Dec, 47(6), 572 - 5
The oral implications of Hodgkin's disease; Herrin HK; Hodgkin's disease is a cancer involving the lymphatics . While the yearly total of new cases is only approximately 7,500, the disease is very curable with modern radiotherapy and/or combination chemotherapy . This represents an increasing number of survivors who require dental treatment . Unfortunately, the treatment for Hodgkin's results in significant, permanent complications that persist for the duration of the patient's life . These complications can include xerostomia, radiation-induced caries, the risk of osteoradionecrosis in irradiated bone, and systemic complications such as a reduced immune response to microorganisms . These patients can and do undergo all types of dental treatment safely as long as the practitioner recognizes the risks involved and takes appropriate precautions.

Hum Pathol, 2000 Feb, 31(2), 263 - 8
Eradication of Borrelia burgdorferi infection in primary marginal zone B-cell lymphoma of the skin; Roggero E et al.; Primary cutaneous B-cell lymphomas have been associated with Borrelia burgdorferi, the spirochete responsible for Lyme disease . Recently, cutaneous marginal zone B-cell lymphoma has been proposed as a distinct clinical-pathological entity . We report a case of primary cutaneous marginal zone lymphoma, associated with B burgdorferi infection . Polymerase chain reaction (PCR) amplification of the third complementarity determining region (CDR3) of the immunoglobulin heavy chain gene showed the presence of a monoclonal lymphoproliferation, therefore strengthening the histological diagnosis of a malignant process . B burgdorfer-specific hbb gene sequences were detected by PCR in the lymphoma tissue at diagnosis but not after antibiotic treatment . A nearly complete clinical and histological regression was observed after B burgdorferi eradication, with immunohistochemistry studies showing disappearance of plasma cell differentiation and a marked decline in the number of CD3+ T cells and Ki-67+ cells . Our case confirms the link between B burgdorferi and some cutaneous lymphomas . The disappearance of the microorganism accompanied by the unequivocal decrease of most indicators of active T- and B-cell immune response strongly supported a pathogenetic role for B burgdorferi in sustaining an antigen-driven development and growth of this cutaneous marginal zone lymphoma . Antibiotic therapy (analogous to Helicobacter pylori infection in gastric MALT lymphoma) might be helpful with the aim of averting or at least deferring the indication for more aggressive treatment.

Int J Immunopharmacol, 2000 Mar, 22(3), 237 - 46
Aflatoxin B(1) inhibits CD14-mediated nitric oxide production in murine peritoneal macrophages; Moon EY et al.; Aflatoxin B(1) (AFB(1)), a potent hepatocarcinogen, has been known to impair non-specific and specific immunity . Macrophages play an important role in host defense against tumors and microorganisms and a number of compounds are implicated in macrophage cytotoxicity . Since activated by the reaction of LPS with CD14, macrophages produce nitric oxide (NO) that is a cytotoxic effector molecule in cell killing . In the present study, we investigated whether the alteration of CD14 level on macrophages by AFB(1) affects NO production in murine peritoneal macrophages . When macrophages were stimulated with LPS after AFB(1)-pretreatment, or they were co-treated with LPS and AFB(1), the NO production decreased in a dose-dependent manner . In contrast, when macrophages were post-treated with AFB(1) after LPS-stimulation, NO production was unchanged . DNA, RNA, and protein synthesis were reduced by AFB(1)-pretreatment of macrophages . The addition of anti-CD14 antibodies to the cultures decreased NO production further . FACS analysis showed that the binding of anti-CD14 antibodies to the macrophages was suppressed by AFB(1)-pretreatment followed by LPS-stimulation . However, AFB(1) does not alter the binding anti-CD14 antibodies to the macrophages without LPS-stimulation . In contrast, AFB(1) pretreatment increased an amount of CD14 released in culture medium . Taken together, these data indicate that the reduced NO production in murine peritoneal macrophages by AFB(1)-pretreatment is related to the suppressed expression of CD14 on macrophage membrane and to the increased secretion of it to culture medium after LPS-stimulation.

Bioessays, 2000 Mar, 22(3), 255 - 63
Phagosome dynamics and function; Tjelle TE et al.; Phagocytosis of microorganisms and other particles is mediated most efficiently by receptors such as Fc-receptors (FcR) and complement-receptors (C3R) . Interaction between these receptors and ligands on the particle results in signal transduction events that lead to actin polymerisation and phagosome formation . The phagosome then undergoes a maturation process whereby it transforms into a phagolysosome . Phagosome maturation depends on interactions (fusion events) with early and late endosomes as well as with lysosomes . The fusion processes are regulated by small GTP-binding proteins and other proteins that are also involved in fusion processes in the endocytic pathway . Although most phagocytosed microorganisms are killed in the lysosome, some pathogens have developed survival strategies and are able to live in the harsh conditions in the phagolysosome or interfere with the maturation process and thereby evade destruction by acid hydrolases .

Hua Xi Yi Ke Da Xue Xue Bao, 1997 Jun, 28(2), 122 - 7
{Immunogenecity of expressed protein p68 from recombinant plasmid rpDJt in L . interrogans serovar lai}; Jiang N et al.; There are two types of infection caused by pathogenic microorganisms, intracellular infection and intercellular infection . Infection of pathogenic leptospira is an intercellular infection . The immunological reaction of host to intercellular infection is unique . The potential immunogen of an expressed protein should meet three criteria: it can be degraded (by antigen-present cells in the host); it should have antigenic epitope which can be recognized by specific antibodies and have at least one epitope that can be recognized by an MHC II protein and T cell receptor . In this study we report the cloning of an L . interrogans protein in plasmid rpDJt and the immunogencity of the expressed protein derivative . A genomic library of L . interrogans serovar lai strain 017 was constructed with the plasmid vector pUC18 . Recombinant plasmids, designated pDJH2 and pDJ8 were screened from the bank . EcoRI-inserted fragment of 1 . 9 kb recombinant DNA of pDJH2 was ligated into T7 RNA polymerase/promoter vectors (pT7-7) . Then they were transformed into E . coli JM109 (De3), one of subclones, designated rpDJt was achieved . SDS-PAGE showed that the molecular weights of expression proteins were 68 kd and 23 kd respectively, designated p68 and p23 . Purifying and isolating p68 and p23, we separated them from SDS-Polyacrylamide gels by using Side-Strip method . After fragmenting and electroeluting, p68 and p23 were injected into guinea pigs and rabbits . An extremely strong immune response to p68 was obtained since an anti-p68 antibody response could be detected to a dilution 1:524,288 (guinea pigs) and 1:262,144 (rabbits) by ELISA while anti-P23 antibody being 1:1024 (the same to guinea pigs and rabbits) . The results of improved MTT and conA 3HTdR transformation methods showed the activities and proliferation of Th-cells were increased in guinea pigs after p68 immunization (IL-6, 83.25 IU/ml, IL-2, 28.75 IU/ml; RPI, 2.04, SI, 65.62%) Thlymphocyte existed in two subclasses, the Th1- and Th2-cells . A major role of Th2-cells is to "help" B-cells differentiate, replicate, and secrete antibody . The properties of these interactions explain why p68 makes good antigen and p23 does not . The antigens responsible for eliciting the production of protective antibodies are not known; however, several outer membrane proteins on L . interrogans are candidates for vaccine . Our results suggest that expresion protein p68 from recombinants (rpDJt) may be a candidate for gene engineered subunit vaccine for Leptospirosis.

Virology, 2000 Mar 1, 268(1), 122 - 31
Limitations of in vivo IL-12 supplementation strategies to induce Th1 early life responses to model viral and bacterial vaccine antigens; Kovarik J et al.; The limited induction of Th1 and cytotoxic immune responses is regarded as the main reason for the increased susceptibility to intracellular microorganisms in early life . Recently, in vitro IL-12 supplementation was shown to enhance the limited IFN-gamma release of measles-specific infant T cells . Using a series of IL-12 delivery systems, we show here that in vivo IL-12 supplementation may enhance early life murine Th1 responses to two model vaccine antigens, measles virus hemagglutinin and tetanus toxin peptide . However, this required multiple repeat injections of recombinant rIL-12, which were poorly tolerated in young mice . Local IL-12 delivery by an IL-12 expressing canarypox vector proved safe but failed to modulate vaccine responses . An IL-12 DNA plasmid or a CD40L DNA plasmid efficiently enhanced neonatal Th1 responses to measles hemagglutinin DNA vaccine . However, both plasmids only enhanced Th1 responses to DNA and not to peptide, protein, or live viral vaccines . Thus, inducing adult-like Th1 responses may be achieved in vivo by inducing (CD40L) or substituting for (IL-12 supplementation) optimal activation of neonatal APC . However, these immunomodulatory effects appear limited to certain antigen-presentation approaches and may not be broadly applicable to vaccines .

J Biotechnol, 2000 Feb 17, 77(2-3), 247 - 53
Calorimetrically recognized maximum yield of poly-3-hydroxybutyrate (PHB) continuously synthesized from toxic substrates; Maskow T et al.; The broader usage of poly-beta-hydroxybutyrate (PHB), for instance as bulk plastics, calls for cheap raw materials and greater overall process efficiency . The bacterial synthesis is generally induced and promoted by the limitation of growth via nitrogen, oxygen or phosphate depletion with the simultaneous excess and higher concentration of the carbon substrate . Consequently, toxic substrates have been considered unsuitable for PHB synthesis . Nevertheless, a single-stage continuous process for producing PHB from toxic substrates using microorganisms was developed and is reported here . The maximum heat flux during continuous growth and the maximum yield of PHB versus the substrate consumption rate were found to coincide . This suggests the possibility of controlling the conversion of a growth-inhibiting substrate into PHB and maximizing the process efficiency . The observed correlation occurred irrespective of the substrates investigated (phenol or sodium benzoate), the PHB-producing strain (Ralstonia eutropha JMP 134 or Variovorax paradoxus JMP 116), or the type of limitation imposed . The maximum PHB yields obtained comprised up to 50% of cell dry mass.

Phytochemistry, 2000 Jan, 53(2), 161 - 76
Phytoalexins from crucifers: synthesis, biosynthesis, and biotransformation; Pedras MS et al.; Phytoalexins play a significant role in the defense response of plants . These secondary metabolites, which are synthesized de novo in response to diverse forms of stress, including fungal infection, are part of the plants' chemical and biochemical defense mechanisms . Phytoalexins from crucifers are structurally and biogenetically related, but display significantly different biological activities . Here, we review work reporting the chemical structures, synthesis, biosynthesis and metabolism of cruciferous phytoalexins, as well as their biological activity towards different microorganisms.

Curr Opin Immunol, 2000 Feb, 12(1), 44 - 51
Human complement regulators: a major target for pathogenic microorganisms; Lindahl G et al.; The C3 convertases of the human complement system are controlled by fluid-phase and membrane proteins in the RCA (regulators of complement activation) family . Accumulated data show that many pathogenic microorganisms interact with these complement regulators . Recent advances in this field include determination of the crystal structure of the binding domains in the measles virus receptor CD46 and identification of a CD46 transgenic mouse line that is sensitive to measles virus . Moreover, recent findings support the hypothesis that pathogenic bacteria binding fluid-phase RCA proteins exploit these proteins to escape complement attack . These studies provide novel insight into the interplay between pathogens and the innate immune system and may have implications for the plans to use animals expressing an RCA protein for xenotransplantation.

Trends Cell Biol, 2000 Mar, 10(3), 85 - 8
Regulation of endocytic traffic by rho family GTPases; Ellis S et al.; Endocytosis is a complicated yet highly efficient process that involves the uptake and processing of cargoes, ranging from small molecules, to activated signalling receptors, to whole microorganisms . Regulation of endocytic pathways is poorly understood . Recent evidence suggests that the Rho GTPase family of signalling proteins is intimately involved in endocytic traffic, providing novel insights into the control mechanisms that govern this process.

J Chromatogr A, 1999 Dec 31, 865(1-2), 129 - 44
Expanded-bed chromatography in primary protein purification; Anspach FB et al.; Chromatography in stable expanded beds enables proteins to be recovered directly from cultivations of microorganisms or cells and preparations of disrupted cells, without the need for prior removal of suspended solids . The general performance of an expanded bed is comparable to a packed bed owing to reduced mixing of the adsorbent particles in the column . However, optimal operating conditions are more restricted than in a packed bed due to the dependence of bed expansion on the size and density of the adsorbent particles as well as the viscosity and density of the feedstock . The feedstock composition may become the most limiting restriction owing to interactions of adsorbent particles with cell surfaces, DNA and other substances, leading to their aggregation and consequently to bed instabilities and channeling . Despite these difficulties, expanded-bed chromatography has found widespread applications in the large scale purification of proteins from mammalian cell and microbial feedstocks in industrial bioprocessing . The basics and implementation of expanded-bed chromatography, its advantages as well as problems encountered in the use of this technique for the direct extraction of proteins from unclarified feedstocks are addressed.

Pediatr Res, 2000 Feb, 47(2), 225 - 32
Detection of microorganisms in the tracheal aspirates of preterm infants by polymerase chain reaction: association of adenovirus infection with bronchopulmonary dysplasia; Couroucli XI et al.; Bronchopulmonary dysplasia (BPD) is recognized as an important cause of morbidity and mortality in preterm infants . Because the role of congenital infections in BPD has been debated, the purpose of this study was to test the hypothesis that detection of infectious agents in tracheal aspirate samples was associated with the development of BPD . Tracheal aspirate samples were obtained within the 1st week of life and screened by polymerase chain reaction for adenovirus, cytomegalovirus, parvovirus, enteroviruses, Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma pneumoniae, and Chlamydia species . BPD was defined as persistent oxygen dependence at 28 d of age and 36 wk postconceptional age (PCA) . Infants that expired before these time points were excluded from statistical analysis . Out of 89 infants studied, at 28 d of life, 13 had expired, 45 had BPD, and 31 had no BPD (controls) . At 36 wk PCA, 15 infants expired, 39 still had BPD, and 35 did not . A significant increase in the frequency of adenovirus genome was identified in BPD patients compared with controls, both at 28 d of life (12/45 = 27% versus 1/31 = 3%: p< or =0.01) and at 36 wk PCA (10/39 = 29% versus 2/35 = 6%: p = 0.01) . Other microorganisms were rarely detected and not associated with the development of BPD . This is the first study reporting the frequency of detection of adenovirus DNA in tracheal aspirate samples obtained during the 1st week of life from infants with BPD and suggests that prenatal acquisition may be important in the development of BPD.

Rev Environ Health, 1999 Jul-Sep, 14(3), 159 - 68
Indoor allergen exposure in west and East Germany: a cause for different prevalences of asthma and atopy?
Hirsch T.
West and East Germans have been living in two different political systems for 40 years . These two populations have become a classic epidemiological example for the hypothesis that lifestyle changes accompanying the industrial and economic development of modern societies are responsible for an increase in the prevalence of atopic diseases . A higher prevalence of atopic sensitization, asthma, and hay fever was found in young West Germans after the unification . It has been hypothesized that this phenomenon was at least partially due to the installation of insulating windows and central heating systems in Western homes, favoring the growth of microorganisms like mites and moulds and increasing indoor allergen exposure . This review summarizes studies that have investigated reservoir concentrations of indoor allergens in public buildings and private homes in East and West Germany . Whereas a higher prevalence of atopic sensitization in West Germans was found for nearly all tested allergens (cat, mite, pollen), allergen exposure was higher only for cat allergens, but probably not for mite and cockroach allergens or moulds . The published data do not support the view that the differences in specific sensitization are caused by differences in the exposure to specific allergens.

Structure Fold Des, 2000 Feb 15, 8(2), 111 - 22
Structure of Aspergillus niger epoxide hydrolase at 1.8 A resolution: implications for the structure and function of the mammalian microsomal class of epoxide hydrolases; Zou J et al.; Background: Epoxide hydrolases have important roles in the defense of cells against potentially harmful epoxides . Conversion of epoxides into less toxic and more easily excreted diols is a universally successful strategy . A number of microorganisms employ the same chemistry to process epoxides for use as carbon sources . Results: The X-ray structure of the epoxide hydrolase from Aspergillus niger was determined at 3.5 A resolution using the multiwavelength anomalous dispersion (MAD) method, and then refined at 1.8 A resolution . There is a dimer consisting of two 44 kDa subunits in the asymmetric unit . Each subunit consists of an alpha/beta hydrolase fold, and a primarily helical lid over the active site . The dimer interface includes lid-lid interactions as well as contributions from an N-terminal meander . The active site contains a classical catalytic triad, and two tyrosines and a glutamic acid residue that are likely to assist in catalysis . Conclusions: The Aspergillus enzyme provides the first structure of an epoxide hydrolase with strong relationships to the most important enzyme of human epoxide metabolism, the microsomal epoxide hydrolase . Differences in active-site residues, especially in components that assist in epoxide ring opening and hydrolysis of the enzyme-substrate intermediate, might explain why the fungal enzyme attains the greater speeds necessary for an effective metabolic enzyme . The N-terminal domain that is characteristic of microsomal epoxide hydrolases corresponds to a meander that is critical for dimer formation in the Aspergillus enzyme.

Res Microbiol, 1999 Nov-Dec, 150(9-10), 579 - 87
Characteristics of Chi distribution on different bacterial genomes; El Karoui M et al.; The availability of full genome sequences provides the bases for analyzing global properties of the genetic text . For example, oligonucleotide sequences that are over- or underrepresented can be identified by taking into account the overall genome composition and organization . One of the most overrepresented oligonucleotides in Escherichia coli is the Chi site, an octanucleotide that stimulates DNA repair by homologous recombination . Here we analyze the genomic distribution of Chi in E . coli and in the three other bacteria where a Chi sequence has been identified; note that Chi is a different sequence in each organism . For each bacterial genome, Chi sequences are frequent, regularly distributed, and overrepresented . This suggests that selection for Chi may have occurred during evolution to favor efficient repair of a damaged chromosome . Other characteristics of Chi distribution are not conserved and might reflect specific features of DNA repair in each host . The different sequence and characteristics of Chi in each microorganism suggest that selection for Chi occurred independently in different bacteria.

J Photochem Photobiol B, 1999 Nov-Dec, 53(1-3), 1 - 6
Measurement of UV radiation using suspensions of microorganisms; Sommer R et al.; The measurement of solar UV radiation is usually performed using physical devices like photodiodes or photomultipliers or with chemical substances (actinometry) . The application of biological material such as microorganisms for this purpose has gained increasing importance in the last few years . The microorganisms may be dried and spread on a flat surface or they may be in aqueous suspensions contained in UV-transparent vessels . If the measurements are done on flat surfaces, the irradiance weighted by the action spectrum of the dried microorganism used is the result of the measurement . If aqueous suspensions of microorganisms are used, contained for instance in spherical vessels, the fluence weighted by the action spectrum of the microorganisms in the aqueous suspension is the result . A problem of this method of measurement can be that inside the vessel the distribution of UV radiation is usually not homogeneous, causing distributions of fluences among the irradiated microorganisms, which may result in variation of the results depending on the mixing characteristics of the suspension during irradiation.

Am J Epidemiol, 2000 Feb 1, 151(3), 324 - 34
Genetic distances for the study of infectious disease epidemiology; Salamon H et al.; Molecular epidemiologic studies of infectious pathogens 1) generate genetic patterns from a collection of microorganisms, 2) compare the degree of similarity among these patterns, and 3) infer from these similarities infectious disease transmission patterns . The authors propose a quantitative approach using genetic distances to study the degree of similarity between patterns . Benefits of such genetic distance calculations are illustrated by an analysis of standard DNA fingerprints of Mycobacterium tuberculosis in San Francisco collected during the period 1991-1997 . Graphical representation of genetic distances can assist in determining if the disappearance of a specific pattern in a community is due to interruption of transmission or ongoing evolution of the microorganism's fingerprint . Genetic distances can also compensate for varying information content derived by DNA fingerprints of contrasting pattern complexity . To study demographic and clinical correlates of transmission, the authors calculated the smallest genetic distance from each patient sample to all other samples . With correlation of genetic distances and nearest genetic distances with previously understood notions of the epidemiology of M . tuberculosis in San Francisco, factors influencing transmission are investigated.

Zentralbl Chir, 1999, 124 Suppl 4, 1 - 8
{General infection prevention in abdominal surgery with special reference to intestinal decontamination}; Schardey HM; In surgery prophylaxis for infection is necessary, because patients are immunocompromised due to the underlying disease and the operation while at the same time being increasingly exposed to potentially pathogenic germs . Prophylaxis is based on the control of endogenous and exogenous microorganisms . For this purpose either systemic or locally active topical agents may be employed . Systemically active substances are applied with the aim to kill and eliminate invasive microorganisms in deep tissue levels, either by their own biological activity or by stimulating specific or unspecific host immune reactions . Local topical measures in contrast are to prevent the primary contact between microorganisms and host . The central pillar of systemic measures is the perioperative systemic antibiotic prophylaxis, immunonutrition is beginning to gain importance, and in the future possibly substances such as G-CSF, which directly stimulate the immune system, may be employed . Standard topical measures are sterilization and desinfection while decontamination of the digestive tract has until now not found a wide spread acceptance . For certain indications especially high risk surgical resections with anastomoses at the level of the oesophagus or the lower rectum it is possible to eliminate endogenous intestinal microorganisms effectively using topical decontamination in combination with systemic antibiotics and improve the surgical results, especially anastomotic healing.

Jpn J Pharmacol, 1999 Dec, 81(4), 317 - 23
Evaluation of NOx in the cardiovascular system: relationship to NO-related compounds in vivo; Ishibashi T et al.; Diverse attention should be paid to evaluating NOx (NO2- and NO3-) in plasma as an index of endothelial nitric oxide (NO) formation in vivo . Nitric oxide, which subsequently appears as NOx, originates from different types of NO synthase and from nonenzymatic reactions . NOx also comes from exogenous sources such as food and gastrointestinal microorganisms . The fate of the NO incorporated into activation of guanylate cyclase, formation of nitrosyl hemoglobin (or nitrosohemoglobin), nitrosothiols, peroxynitrite and its derivatives and other possible compounds is not clear at present . However, some of these compounds would produce NOx as by-products or as final products through metabolism . Therefore, plasma NOx contains information about these pathways, although how extensively these factors contribute to plasma NOx has not been quantitatively defined . A theoretical simulation of NOx in the systemic circulation indicates that only small changes are expected by inhibition or stimulation of endothelial NO production . Measuring NOx production during coronary circulation has the advantage that some degree of NOx accumulation is expected from intact endothelial cells because an excretion system is absent in the heart.

Invest Clin, 1999 Dec, 40(4), 277 - 300
{The NADPH-oxidase complex in chronic granulomatous disease: preliminary description of a cluster in Mérida-Venezuela}; Salmen S et al.; Chronic Granulomatous Disease (CGD) is a primary immunodeficiency characterized by an unusual predisposition to develop bacterial and fungal infections due to a failure of phagocytic leukocytes to generate superoxide, required for the intracellular killing of microorganisms . The lack of superoxide production is secondary to a defect in the NADPH-oxidase enzymatic complex activation, as a result of mutations of any of the components . Both, X-linked and autosomal recessive patterns of inheritance have been demonstrated in this disease, being the X-linked the most frequent and characterized by mutations in gp91phox . Mutations in p47phox, p67phox and p22phox have been shown in the autosomal recessive pattern . The molecular and genetic characteristic of NADPH-oxidase complex and its pathology in CGD are reviewed along with a brief description of the preliminary findings in two families from Merida, Venezuela.

Orig Life Evol Biosph, 1999 Dec, 29(6), 625 - 31
Did Viking discover life on Mars?
Klein HP.
A major argument in the claim that life had been discovered during the Viking mission to Mars is that the results obtained in the Labeled Release (LR) experiment are analogous to those observed with terrestrial microorganisms . This assertion is critically examined and found to be implausible.

HNO, 2000 Feb, 48(2), 147 - 51
{Herpes simplex virus type 1-induced rising dbl quote, left (low)tumor" in the nasal vestibule . The problem of resistance development of herpes simplex in a patient with chronic lymphatic B-cell leukemia}; Althof F et al.; Herpes simplex viruses are known to be among the most common disease-causing microorganisms . Their prevalence can exceed 90% depending on the socioeconomic status of the population . Since the number of immunocompromised patients has increased because of the increased incidence in the acquired immunodeficiency syndrome and an increase in organ transplantation, herpes virus infection may have a greater clinical significance . While treatment of otherwise healthy individuals will not usually cause any clinical problems herpes infection in an immunocompromised patient can have severe consequences . Additionally, development of viral resistance can be observed that may require alternative drugs in treatment . We present a case history of a man with a B-cell chronic lymphocytic leukemia that was associated with a very unusual herpes simplex virus infection in the nasal vestibule . Possible causes for the development of resistance in herpes infections and the use of famciclovir and forscarnet as two therapeutic alternatives to aciclovir are discussed.

Trends Microbiol, 2000 Feb, 8(2), 68 - 73
New perspectives on nitrogen-fixing microorganisms in tropical and subtropical oceans; Zehr JP et al.; New molecular and microscopic evidence indicates that the open ocean harbors a diverse range of novel free-living and symbiotic nitrogen-fixing microorganisms . Although the extent to which these microorganisms fix nitrogen is currently unclear, ongoing research indicates that they might make a substantial contribution to the open ocean nitrogen budget.

J Biol Chem, 2000 Feb 11, 275(6), 3977 - 83
The multiple activities of polyphosphate kinase of Escherichia coli and their subunit structure determined by radiation target analysis; Tzeng CM et al.; Polyphosphate kinase (PPK), the principal enzyme required for the synthesis of inorganic polyphosphate (polyP) from ATP, also exhibits other enzymatic activities, which differ significantly in their biochemical optima and responses to chemical agents . These several activities include: polyP synthesis (forward reaction), nATP --> polyP(n) + nADP (Equation 1); ATP synthesis from polyP (reverse reaction), ADP + polyP(n) --> ATP + polyP(n - 1) (Equation 2); general nucleoside-diphosphate kinase, GDP + polyP(n) --> GTP + polyP(n - 1) (Equation 3); linear guanosine 5'-tetraphosphate (ppppG) synthesis, GDP + polyP(n) --> ppppG + polyP(n - 2) (Equation 4); and autophosphorylation, PPK + ATP --> PPK-P + ADP (Equation 5) . The Mg(2+) optima are 5, 2, 1, and 0.2 mM, respectively, for the activities in Equations 1, 2, 3, and 4 . Inorganic pyrophosphate inhibits the activities in Equations 1 and 3 but stimulates that in Equation 4 . The kinetics of the activities in Equations 1, 2, and 3 are highly processive, whereas the transfer of a pyrophosphoryl group from polyP to GDP (Equation 4) is distributive and demonstrates a rapid equilibrium, random Bi-Bi catalytic mechanism . Radiation target analysis revealed that the principal functional unit of the homotetrameric PPK is a dimer . Exceptions are a trimer for the synthesis of ppppG (Equation 4) and a tetrameric state for the autophosphorylation of PPK (Equation 5) at low ATP concentrations . Thus, the diverse functions of this enzyme involve different subunit organizations and conformations . The highly conserved homology of PPK among 18 microorganisms was used to determine important residues and conserved regions by alanine substitution, by site-directed mutagenesis, and by deletion mutagenesis . Of 46 single-site mutants, seven exhibit none of the five enzymatic activities; in one mutant, ATP synthesis from polyP is reduced relative to GTP synthesis . Among deletion mutants, some lost all five PPK activities, but others retained partial activity for some reactions but not for others.

Caring, 1999 Nov, 18(11), 6 - 11
Preventing and controlling the transmission of antibiotic-resistant microorganisms in the home care setting; Friedman MM; Antibiotic-resistant microorganisms can spread to other home care patients by an infected or colonized patient receiving home care services and the home care staff member unknowingly carrying it to another home care patient's home . Controlling the transmission of antibiotic-resistant microorganisms is the primary responsibility of those providing direct patient care . The ultimate goal for home care is to prevent staff colonization and cross-contamination to other home care patients.

Semin Thorac Cardiovasc Surg, 1999 Oct, 11(4 Suppl 1), 157 - 62
The Toronto SPV bioprosthesis: review of morphological findings in eight valves; Butany J et al.; The morphological findings in eight explanted Toronto SPV bioprostheses were described . Clinical records were reviewed for patient information and data regarding the explanted bioprosthesis, all of which were analyzed in detail by gross and histological examination . All valves were also examined radiologically and detailed specimen photographs obtained . When warranted, tissue cultures were taken and special stains for microorganisms obtained . The Toronto SPV bioprosthesis has been used for aortic valve replacement in 270 patients since its introduction in 1991 . The follow-up evaluation was 99.5% complete . Eight valves have been explanted: three at surgery and five at autopsy . Patient age ranged from 35 to 69 years, with five male and three female patients . Indications for aortic valve replacement were aortic stenosis in all cases . Implant duration ranged from 5 weeks to just over 6 years (mean 38 months) . Early failures (2) were due to infective endocarditis . Two patients died of acute myocardial infarction, related to pre-existing coronary artery disease, and two died from lung cancer . All late explants showed host tissue growth (grade 2-3), with variable extension onto both the proximal and distal suture lines, as well as extension onto the cusps and commissures on the flow and nonflow surfaces . Extension of pannus onto native aortic tissues was seen but did not encroach on the coronary ostia . Tissue degenerative changes were present, as were small tears (type 1) in two valves . Mild calcification was seen in two valves . The Toronto SPV has excellent clinical performance at up to 8 years of follow-up evaluation . In this series, early failures are related to infective endocarditis, and later explants (6 of 8) are associated with mild tissue degeneration and an occasional cusp tear . At up to 5 years, only minimal/mild calcification was seen in two of the eight valves.

Adv Exp Med Biol, 1999, 473, 319 - 37
New approaches to mucosal immunization; Cardenas-Freytag L et al.; Every year more than 17 million deaths worldwide are caused by infectious diseases . The great majority of these deaths occur in underdeveloped countries and are attributed to diseases preventable by existing vaccines, or diseases that could potentially be prevented with new vaccines . The fact that most human and veterinary pathogens establish infection in the host by initiating contact at a mucosal surface, provide the rationale for the development of mucosal vaccines . An increasing number of strategies have been proposed to facilitate mucosal immunization . Among the most widely investigated strategies are the use of attenuated microorganisms; the inclusion of immunizing antigens in lipid-based carriers, the genetic creation of transgenic plants and the use of mucosal adjuvants derived from bacterial toxins . This review provides a brief summary of the most recent advances in the field of mucosal immunization with an special emphasis on a promising genetically detoxified mucosal adjuvant, LT(R192G), derived from the heat-labile toxin of enterotoxigenic E . coli . We present evidence regarding the safety, immunogenicity, and efficacy of LT(R192G) for the development of a new generation of mucosal vaccines.

J Immunol, 2000 Feb 15, 164(4), 2193 - 9
CD47 engagement inhibits cytokine production and maturation of human dendritic cells; Demeure CE et al.; Upon encounter with bacterial products, immature dendritic cells (iDCs) release proinflammatory cytokines and develop into highly stimulatory mature DCs . In the present study, we show that human monocyte-derived DCs functionally express the CD47 Ag, a thrombospondin receptor . Intact or F(ab')2 of CD47 mAb suppress bacteria-induced production of IL-12, TNF-alpha, GM-CSF, and IL-6 by iDCs . 4N1K, a peptide derived from the CD47-binding site of thrombospondin, also inhibits cytokine release . The inhibition of IL-12 and TNF-alpha is IL-10-independent inasmuch as IL-10 production is down-modulated by CD47 mAb and blocking IL-10 mAb fails to restore cytokine levels . CD47 ligation counteracts the phenotypic and functional maturation of iDCs in that it prevents the up-regulation of costimulatory molecules, the loss of endocytic activity, and the acquisition of an increased capacity to stimulate T cell proliferation and IFN-gamma production . Interestingly, regardless of CD47 mAb treatment during DC maturation, mature DC restimulated by soluble CD40 ligand and IFN-gamma, to mimic DC/T interaction, produce less IL-12 and more IL-18 than iDCs . Finally, CD47 ligation on iDCs does not impair their capacity to phagocytose apoptotic cells . We conclude that following exposure to microorganisms, CD47 ligation may limit the intensity and duration of the inflammatory response by preventing inflammatory cytokine production by iDCs and favoring their maintenance in an immature state.

Aviakosm Ekolog Med, 1999, 33(6), 48 - 52
{Endogenous regulatory peptides, interferons and cytokines as adaptogens in exposure of the body to adverse environmental factors}; Kalinin IuT et al.; The authors summarize data on the efficacy of various prefabricated recombinant interferons against virus, bacterial, and chlamydial infections, and in unfavorable environments . The spaceflight factors were shown to have a negative influence on natural killers in the human body providing the immunological resistance and defence not only from foreign microorganisms but also the body cells transformed because of a virus infection or malignancy . Entalferon awakes a particular interest for its convenience in extreme conditions, space flight included . It is still an open issue whether the interferon sensitivity of natural killers is compromised by space flight . This trend of investigation seems to be of paramount importance and promise in the context of enhancing the antiviral, antimicrobic and antineoplastic immunity of cosmonauts.

Pediatrics, 2000 Feb, 105(2), 311 - 5
Detection of pathogen transmission in neonatal nurseries using DNA markers as surrogate indicators; Oelberg DG et al.; OBJECTIVE: Nosocomial infections are a major problem confronting neonatal intensive care units (NICUs) . This study was conducted to determine if DNA markers designed from the cauliflower mosaic virus (CaMV 35S DNA) can serve as surrogate indicators of nosocomial pathogen transmission in NICUs . METHODS: Regions of cauliflower CaMV 35S promoter DNA were designed to serve as surrogate markers of microbial transmission pathways . Each of 6 pods within the NICU under study houses 8 newborn infants . DNA marker was placed on the telephone handle in only 1 of the 6 NICU pods (study pod) . Bedside caregivers were blinded as to when placebo or marker were placed in the pod . Thirty-two samples were collected from predetermined sites within each pod at 0, 4, 8, 24, and 48 hours and 7 days after DNA placement . Similar sites were sampled in each of the 6 pods . Additional samples were collected concurrently from areas of the NICU segregated from direct patient care . Polymerase chain reactions were performed on collected samples, and products were analyzed by agarose gel electrophoresis . RESULTS: One thousand three hundred samples of the environment and hands of personnel were collected and analyzed . Within the study pod, 58% of sites tested positive for the DNA marker throughout all time points; positive sites peaked at 8 hours (78%) and declined to 23% positive at 7 days . The other 5 pods had a mean of 18% of sites positive throughout the 7 days and exhibited a similar decline throughout time . The most consistently positive sites within all pods were the blood gas analyzers, computer mice, telephone handles, medical charts, ventilator knobs, door handles, radiant warmer control buttons, patient monitors, and personnel hands . In areas outside the pods, the nurse's station, resident physician charting area, changing room, and staff break room had a mean of 50% positive sites throughout all time points . CONCLUSIONS: DNA markers proved useful as safe, surrogate indicators of microorganism transmission within and outside pods in the NICU . We speculate that utilization of these techniques in the hospital environment will provide important information about transmission of pathogens in the NICU, assist in developing and enforcing cleaning procedures, and permit testing of educational intervention programs targeting a decrease in nosocomial infections.nosocomial infection, neonatal intensive care, DNA marker, polymerase chain reaction, infection control.

Aliment Pharmacol Ther, 2000 Feb, 14(2), 247 - 56
Characterization of M cell development during indomethacin-induced ileitis in rats; Kucharzik T et al.; BACKGROUND: M cells play an important role in the intestinal immune system as they have a high capacity for transcytosis of a wide range of microorganisms and macromolecules . However, little is known about the role of M cells during intestinal inflammation . AIM: We studied M cell development during indomethacin-induced intestinal inflammation in rats . METHODS: Ileitis in rats was induced by two subcutaneous injections with indomethacin (7.5 mg/kg) given 24 h apart . Rats were sacrificed after 14 days and tissue was analysed by fluorescence microscopy and electron microscopy . M cells could be visualized by using the FITC-labelled mAb anti-cytokeratin (CK)-8 (clone 4.1.18), which was recently identified as specific M cell marker in rats . The number of cytokeratin-8 positive M cells was related to the surface of the follicle associated epithelium . For morphological studies, we used both transmission electron microscopy (T.E.M.) and scanning electron microscopy (S.E.M.) . RESULTS: In non-inflamed ileum M cells were scarce . Only 4% of the follicle associated epithelium were M cells, whereas an increase of M cells up to 11% was found in inflamed follicle associated epithelium (P < 0.001) . The rate of M cell induction depended on the macroscopic degree of inflammation . T.E.M./S.E.M . studies showed that in inflamed tissue most M cells underwent apoptosis with typical morphological signs . In contrast to apoptotic M cells, the neighbouring enterocytes usually appeared intact . The number of mononuclear cells below the follicle associated epithelium was significantly increased . S.E.M . studies revealed that during induced ileitis mononuclear cells migrated from the lamina propria into the gut lumen by passing through apoptotic M cells . CONCLUSIONS: During indomethacin-induced ileitis in rats the increase in M cell number in association with apoptosis of M cells may alter the intestinal barrier function . These observations may play a pivotal role in the pathogenesis of chronic intestinal inflammation, e.g . in inflammatory bowel disease.

Phytochemistry, 1999 Dec, 52(7), 1203 - 10
Effectiveness of ascorbate and ascorbate peroxidase in promoting nitrogen fixation in model systems; Ross EJ et al.; Ascorbate and ascorbate peroxidase are important antioxidants that are abundant in N2-fixing legume root nodules . Antioxidants are especially critical in root nodules because leghemoglobin, which is present at high concentrations in nodules, is prone to autoxidation and production of activated oxygen species such as O2.- and H2O2 . The merits of ascorbate and ascorbate peroxidase for maintaining conditions favorable for N2 fixation were examined in two model systems containing oxygen-binding proteins (purified myoglobin or leghemoglobin) and N2-fixing microorganisms (free-living Azorhizobium or bacteroids of Bradyrhizobium japonicum) in sealed vials . The inclusion of ascorbate alone to these systems led to enhanced oxygenation of hemeproteins, as well as to increases in nitrogenase (acetylene reduction) activity . The inclusion of both ascorbate and ascorbate peroxidase resulted in even greater positive responses, including increases of up to 4.5-fold in nitrogenase activity . In contrast, superoxide dismutase did not provide beneficial antioxidant action and catalase alone provided only very marginal benefit . Optimal concentrations were 2 mM for ascorbate and 200 micrograms/ml for ascorbate peroxidase . These concentrations are similar to those found in intact soybean nodules . These results support the conclusion that ascorbate and ascorbate peroxidase are beneficial for maintaining conditions favorable for N2 fixation in nodules.

Plant Mol Biol, 1999 Nov, 41(5), 669 - 77
Comparative differential RNA display analysis of arbuscular mycorrhiza in Pisum sativum wild type and a mutant defective in late stage development; Lapopin L et al.; In order to analyse gene expression associated with the late stages of arbuscular mycorrhizal development between Pisum sativum and Glomus mosseae, comparative differential RNA display was carried out using wild-type P . sativum and a mutant, RisNod24, where the fungal partner is not able to form functional arbuscules . Comparison of RNA accumulation patterns between controls, G . mosseae-colonized mutant and wild-type roots resulted in the identification of four differentially occurring cDNA fragments . One of the corresponding genes was from the fungus and three of plant origin . One plant gene, Psam4 (P . sativum arbuscular mycorrhiza-regulated), was analysed in more detail . Sequencing of a cDNA clone showed that Psam4 encodes a proline-rich protein . Northern blot analysis and quantitative RT-PCR revealed a higher basal level of Psam4 RNA accumulation in the mutant compared to the wild type . In both pea genotypes, RNA accumulation was reduced after inoculation with mycorrhiza- or nodule-forming symbiotic microorganisms, but enhanced after infection with a root pathogenic fungus.

Bioorg Khim, 1999 Nov, 25(11), 811 - 5
{Endogenous immunoregulatory peptides (myelopeptides): structure, function, and mechanism of action}; Petrov RV et al.; Previously unknown bioregulators from bone marrow, myelopeptides, were isolated, identified, and synthesized, and their biological properties and mechanism of action were studied in detail . Phe-Leu-Gly-Phe-Pro-Thr (MP-1) manifests an immunocorrecting effect by restoring the level of antibody production in animals suffering from immunodeficiencies of various etiologies; Leu-Val-Val-Tyr-Pro-Trp (MP-2) manifests an antitumor effect by abolishing the inhibitory action of tumor cells on the functional activity of T-lymphocytes; Leu-Val-Cys-Tyr-Pro-Gln (MP-3) stimulates phagocytosis by macrophages and, in this way, protects animals from infections caused by pathogenic microorganisms; and Phe-Pro-Arg-Ile-Met-Thr-Pro (MP-4) is a new factor of cell differentiation inducing terminal cell differentiation in the HL-60 and K-562 leukemic cell lines.

Vet Pathol, 2000 Jan, 37(1), 82 - 5
Small intestinal adenomatous polyposis resulting in protein-losing enteropathy in a horse; Patterson-Kane JC et al.; A 4-year-old Quarter Horse gelding was presented with a history of weight loss of 6 months duration, along with extensive ventral subcutaneous edema . Clinicopathologic findings included a markedly low serum total protein (2.9 g/dl) and a low packed cell volume (24%) . The mucosal surface of the distal jejunum and entire ileum were carpeted with numerous polypoid, papillary, and glandular masses comprised of pseudostratified tall columnar cells and large numbers of interspersed goblet cells . Neoplastic change was diffuse throughout the mucosa of each mass, but abrupt demarcation occurred between neoplastic masses and adjacent mucosa . Immunohistochemical staining for protein of the p53 tumor suppressor gene revealed only occasional cytoplasmic reactivity within polyps and normal mucosa . Nuclear staining for papillomavirus antigens was not observed . Electron microscopic examination revealed features of well-differentiated intestinal epithelial cells, including apical tight junctions and microvilli, desmosomes, and the presence of numerous goblet cells . Microorganisms were not detected . Small intestinal polyposis should be considered as a rare differential diagnosis for protein-losing enteropathy in the horse.

Dev Biol, 1999 Dec 15, 216(2), 426 - 41
Regulation of cell-fate determination in Dictyostelium; Brown JM et al.; A key step in the development of all multicellular organisms is the differentiation of specialized cell types . The eukaryotic microorganism Dictyostelium discoideum provides a unique experimental system for studying cell-type determination and spatial patterning in a developing multicellular organism . Unlike metazoans, which become multicellular by undergoing many rounds of cell division after fertilization of an egg, the social amoeba Dictyostelium achieves multicellularity by the aggregation of approximately 10(5) cells in response to nutrient depletion . Following aggregation, cell-type differentiation and morphogenesis result in a multicellular organism with only a few cell types that exhibit a defined patterning along the anterior-posterior axis of the organism . Analysis of the mechanisms that control these processes is facilitated by the relative simplicity of Dictyostelium development and the availability of molecular, genetic, and cell biological tools . Interestingly, analysis has shown that many molecules that play integral roles in the development of higher eukaryotes, such as PKA, STATs, and GSK-3, are also essential for cell-type differentiation and patterning in Dictyostelium . The role of these and other signaling pathways in the induction, maintenance, and patterning of cell types during Dictyostelium development is discussed.

Infect Immun, 2000 Feb, 68(2), 680 - 7
Epitope mapping of immunogenic and adhesive structures in repetitive domains of Mycoplasma bovis variable surface lipoproteins; Sachse K et al.; The family of variable surface lipoproteins (Vsps) of the bovine pathogen Mycoplasma bovis includes some of the most immunogenic antigens of this microorganism . Vsps were shown to undergo high-frequency phase and size variations and to possess extensive reiterated coding sequences extending from the N-terminal end to the C-terminal end of the Vsp molecule . In the present study, mapping experiments were conducted to detect regions with immunogenicity and/or adhesion sites in repetitive domains of four Vsp antigens of M . bovis, VspA, VspB, VspE, and VspF . In enzyme-linked immunosorbent assay experiments, sera obtained from naturally infected cattle showed antibodies to different repeating peptide units of the Vsps, particularly to units R(A)1, R(A)2, R(A)4.1, R(B)2.1, R(E)1, and R(F)1, all of which were found to contain immunodominant epitopes of three to seven amino acids . Competitive adherence trials revealed that a number of oligopeptides derived from various repeating units of VspA, VspB, VspE, and VspF partially inhibited cytoadhesion of M . bovis PG45 to embryonic bovine lung cells . Consequently, putative adherence sites were identified in the same repeating units (R(A)1, R(A)2, R(A)4.1, R(B)2.1, R(E)1, and R(F)1) and in R(F)2 . The positions and lengths of the antigenic determinants were mostly identical to those of adhesion-mediating sites in all short repeating units, whereas in the considerably longer R(F)1 unit (84 amino acid residues), there was only one case of identity among four immunogenic epitopes and six adherence sites . The identification of epitopes and adhesive structures in repetitive domains of Vsp molecules is consistent with the highly immunogenic nature observed for several members of the Vsp family and suggests a possible function for these Vsp molecules as complex adherence-mediating regions in pathogenesis.

Gynecol Oncol, 2000 Feb, 76(2), 176 - 82
Expression of complement regulatory proteins-CD 35, CD 46, CD 55, and CD 59-in benign and malignant endometrial tissue; Murray KP et al.; OBJECTIVE: Complement system plays an important role in host defense mechanisms against microorganisms and tumor cells . To protect themselves from autologous complement-mediated damage, normal host tissues express cell membrane-associated complement regulatory proteins (CRPs) . To investigate whether neoplastic endometrial tissues overexpress these proteins to escape complement damage, we examined the distribution of complement receptor type 1 (CR1, CD35), membrane cofactor protein (MCP, CD46), decay-accelerating factor (DAF, CD55), and protectin (MACIF, CD59) on frozen endometrial tissue samples . METHODS: A total of 54 endometrial tissue samples were collected . Cryosections were obtained of 31 benign and 23 malignant tissue specimens . Tissue sections were stained by immunohistochemical staining procedure using specific antibodies and employing the avidin-biotin technique . Quantitation of the protein content of these CRPs was determined using the Samba 4000 image analysis system . RESULTS: For all four of the CRPs studied, a statistically significant difference in protein expression between the benign and malignant endometrial tissue specimens (P < 0.0001) was observed . CONCLUSIONS: Overexpression of all the CRPs studied (CD35, CD46, CD55, CD59) was observed in the malignant as compared with the benign endometrial tissues . The upregulation of these CRPs may promote resistance of the endometrial malignant tissue to complement-mediated damage, thereby allowing the tumor cells to escape from cytolysis and thus promoting carcinogenesis .

Rev Clin Esp, 1999 Nov, 199(11), 705 - 10
{Pyogenic liver abscess: changes in etiology, diagnosis and treatment over 18 years}; Corredoira Sanchez JC et al.; BACKGROUND: There are no detailed studies in our country on the impact of modern imaging techniques on diagnosis, treatment and prognosis of pyogenic liver abscesses . MATERIAL AND METHODS: All patients with the diagnosis of PLA from 1981 to 1998 were included in the study . The study was divided in two periods: 1981 to 1989 and 1990 to 1998 . RESULTS: Compared with the first time period, the following was observed from 1990 to 1998: the mean age was higher (52 versus 65 years, p = 0.006), infections with identified source increased (33% versus 74%, p = 0.003), diagnosis was earlier (13 versus 3 days, p = 0.0002), modern imaging techniques were used more frequently (17% versus 96%, p = 0.002), the proportion of recovered microorganisms increased (53% versus 88%, p = 0.002), as well as use of percutaneous drainage (0% versus 37%, p = 0.002) and the prognosis was better (mortality rate 40% versus 10%, p = 0.01) . CONCLUSIONS: Relevant changes were observed among patients in our hospital in the nineties regarding epidemiology, management and prognosis of PLAs . Part of these changes are due to a higher use of new imaging techniques.

Berl Munch Tierarztl Wochenschr, 1999 Dec, 112(12), 454 - 8
{Nature and frequency of the existence of mold fungi in garbage cans for biological waste and the resultant airborne spore pollution}; Weinrich M et al.; In organic waste, numerous mold fungi and other microorganisms develop sometimes within a few hours only which decompose the organic material already in the collecting containers generating heat and odor . With regard to the emission of mold fungus spores out of garbage cans for bio-waste and the potential environmental-hygienic danger connected with it, considerable worries have been expressed recently . A wide spectrum of mold fungi can be found in bio-waste in strongly varying concentrations . No noticeable difference could be ascertained between the settlement structure areas and the cities respectively as to the fungus concentration in the bio-waste substrate . A . fumigatus and A . niger can be recommended as leading spores for the behavior of the total concentration of fungi in the bio-waste due to their frequency of detection and their seasonal dynamism . The intensity of the air spore pollution through emission of mold fungus spores correlates closely with the climatic conditions, such as variations of temperature, relative humidity and solar radiation . The airborne release of mold fungus spores out of garbage cans for bio-waste and the formation of a respective exposure connected with it is judged as harmless for healthy persons . Risk patients and persons having a weakened immune system or assumed to have such a one due to an existent basic illness and/or other reasons should avoid any handling of bio-waste as well as any other waste if possible.

Circulation, 2000 Jan 18, 101(2), 137 - 41
Association of serology with the endovascular presence of Chlamydia pneumoniae and cytomegalovirus in coronary artery and vein graft disease; Bartels C et al.; BACKGROUND: Chemotherapeutic treatment for patients with symptomatic coronary artery disease to reduce cardiovascular events may be initiated in response to elevated antibody titers against Chlamydia pneumoniae or cytomegalovirus . How antibody titers are associated with the endovascular presence of these microorganisms is still unclear . METHODS AND RESULTS: Antibody titers against C pneumoniae (microimmunofluorescence) and cytomegalovirus (ELISA) in patients undergoing primary (coronary desobliterates, n=80) or repeated CABG (occluded vein grafts, n=45) were correlated with the endovascular presence of the 2 microorganisms . C pneumoniae was detected by means of a nested polymerase chain reaction (PCR) and by culturing . Both conventional PCR and quantitative PCR were applied for detection of cytomegalovirus . C pneumoniae (PCR/culture) was detected in 19/9% (15/80 and 7/80) of coronary desobliterates and in 18/11% (8/45 and 5/45) of occluded vein grafts . There was no statistical evidence that IgG values differed between patients with or without C pneumoniae detection who were undergoing primary CABG . In contrast, repeated-CABG patients with a positive PCR (P=0.0027) or C pneumoniae culture (P=0.0018) had distinctly elevated IgG titers compared with patients in whom C pneumoniae was not detected . Cytomegalovirus could not be detected in the examined specimens . CONCLUSIONS: Cytomegalovirus infection does not seem to be associated with advanced coronary artery lesions . C pneumoniae antibody titers are not associated with the endovascular presence of C pneumoniae in patients with coronary artery disease . The observed strong association between elevated IgG titers and the detection of C pneumoniae in occluded vein grafts warrants further investigation.

Chemosphere, 1999 Dec, 39(15), 2723 - 36
A comparative investigation on the biosorption of lead by filamentous fungal biomass; Lo W et al.; The removal of lead from aqueous solutions by adsorption on filamentous fungal biomass was studied . Batch biosorption experiments were performed to screen a series of selected fungal strains for effective lead removal at different metal and biomass concentrations . Biosorption of the Pb2+ ions was strongly affected by pH . The fungal biomass exhibited the highest lead adsorption capacity at pH 6 . Isotherms for the biosorption of lead on fungal biomass were developed and the equilibrium data fitted well to the Langmuir isotherm model . At pH 6, the maximum lead biosorption capacity of Mucor rouxii estimated with the Langmuir model was 769 mg/g dry biomass, significantly higher than that of most microorganisms . Biomass of Mucor rouxii showed specific selectivity for Pb2+ over other metals ions such as Zn2+, Ni2+ and Cu2+ . This fungal strain may be applied to develop potentially cost-effective biosorbent for removing lead from effluents . The technique of scanning electron microscopy coupled with X-ray dispersion analysis shows that Pb2+ has exchanged with K+ and Ca2+ on the cell wall of Mucor rouxii, thereby suggesting ion exchange as one of the dominant mechanisms of metal biosorption for this fungal strain.

Aliment Pharmacol Ther, 2000 Jan, 14(1), 15 - 22
Personal review: is profound acid inhibition safe?
Waldum HL, Brenna E.
Inhibitors of gastric acid secretion, particular proton pump inhibitors, are effective drugs in the treatment and prophylaxis of acid-related diseases . Proton pump inhibitors are therefore prescribed widely, often for minor complaints . Gastric acidity kills swallowed microorganisms, and acid secretion must be of biological importance because it is maintained in phylogenesis . Acid secretion is controlled by feedback mechanisms, mainly via gastrin . A decrease in acidity always causes an increase in plasma gastrin . The trophic effect of gastrin leads to hyperplasia and neoplasia of the enterochromaffin-like (ECL) cell . ECL cell derived tumours in man were previously regarded as rare, and also as rather benign . It is now clear that the ECL cell gives rise to a significant proportion of gastric carcinomas . Moreover, ECL cell carcinoids secondary to hypergastrinaemia may develop into highly malignant tumours . Treatment with a proton pump inhibitor is followed by rebound acid hypersecretion and decreased efficiency of H2-blockers, thus such treatment may induce a type of physical dependence . It is therefore reasonable to be cautious and not to treat younger (< 50 years) patients for long periods of time with profound inhibitors of gastric acid secretion . Chromogranin A in the blood is a sensitive marker of the ECL cell mass, and it could be used to survey patients on long-term proton pump inhibitors.

Bioorg Med Chem, 1999 Nov, 7(11), 2329 - 41
Microbial models of drug metabolism: microbial transformations of Trimegestone (RU27987), a 3-keto-delta(4,9(10))-19-norsteroid drug; Lacroix I et al.; Screening microorganisms for the biotransformation of the 3-keto-delta(4,9(10))-19-norsteroid RU27987 (Trimegestone) resulted in the isolation of nine identified metabolites, some of them being selectively produced by different strains . Eight metabolites were found to be hydroxylated on various positions of the rings, and one was additionally epoxidized . These microbial metabolites could be used as chromatographic standards and two of them were found identical to the unknown major human metabolites . Moreover, most microbial metabolites were produced in sufficient amounts to be tested for their biological activities . All these features demonstrate the usefulness and versatility of microbial biotransformation systems as a tool for early identification and convenient production of potentially active mammalian and non-mammalian metabolites.

Trends Biotechnol, 2000 Jan, 18(1), 19 - 21
Environmental biotechnology; Wackett LP; There is an increasing interest in environmental biotechnology owing to a worldwide need to feed the world's growing population and to maintain clean soil, air and water . The major technological developments are in plant and microbial biology . Plants can be more readily engineered for resistances that enhance yield or produce new products whereas microorganisms are exploited for their catalytic diversity and ease of genetic engineering.

Toxicol Sci, 1999 Dec, 52(2 Suppl), 107 - 10
Conjugated linoleic acid and the control of cancer and obesity; Pariza MW et al.; The effects of conjugated linoleic acid (CLA) in animals are reviewed . In most of the CLA preparations that have been investigated to date for biological activity, two CLA isomers are present in about equal concentrations: cis-9,trans-11 CLA, and trans-10,cis-12 CLA . The occurrence of these isomers in foods and their production by rumen microorganisms are discussed . Potential mechanisms of action as regards the effects of CLA on cancer and body composition are reviewed, including recent evidence that body composition changes are produced by the trans-10,cis-12 CLA isomer . Evidence is presented indicating that CLA may modulate cellular response to tumor necrosis factor-alpha (TNF-alpha) . The mechanistic implications of this finding are considered.

J Dairy Sci, 1999 Dec, 82(12), 2651 - 8
Evidence of a role for plant proteases in the degradation of herbage proteins in the rumen of grazing cattle; Zhu WY et al.; Protein breakdown in the rumen is generally regarded as a two-stage process in which proteases produced by rumen microorganisms cleave plant protein into peptides and amino acids . However, many of the fiber-degrading cellulolytic species in the rumen are not in fact proteolytic, and the proteolytic activity of the entire rumen microbial population is only moderate when compared to the gastric and pancreatic secretions in the abomasum . Moreover, plant cell walls remain largely intact after initial chewing (particularly in cattle), presenting a physical barrier that must be breached prior to their effective colonization . The present study considers the hypothesis that the plant enzymes are at least partly responsible for herbage protein degradation in grazing ruminants . Ryegrass, red clover, white clover, and bird's-foot trefoil were incubated in the presence and absence of rumen microorganisms . The production of volatile fatty acids indicated the level of microbial activity, whereas the relative disappearance of the large subunit of ribulose 1,5 bisphosphate carboxylase/oxygenase (Rubisco LSU) indicated proteolytic activity . In all incubations, the relative abundance of the Rubisco LSU decreased as the incubation progressed . When rumen microorganisms were absent, low molecular weight peptides (below 20 kDa) accumulated as the incubation progressed . This accumulation was not observed in the presence of rumen microorganisms . Therefore we suggest that the intrinsic plant proteases contribute to the initial stages of proteolysis of grazed herbage.

Antibiot Khimioter, 1999, 44(11), 23 - 30
{The comparative activity of cefepime and other current antibiotics against microorganisms isolated from patients in pediatric intensive therapy units}; Kurchavov VA et al.; Comparative activity of cefepime, ceftazidime, ceftriaxone, ciprofloxacin, imipenem and piperacillin/tazobactam against isolates from patients of pediatric intensive care units within October-December 1998 was studied . The isolates were identified with the Walkaway-40 System . The antibiotic susceptibility was evaluated by the E-test on the Mueller-Hinton II agar . The data were interpreted in accordance with the NCCLS . The number of the isolates totaled 100 . Among them not more than 10 to 12 strains belonged to the same species . 92 per cent of the isolates was susceptible to cefepime and 70 to 75 per cent of the isolates were susceptible to the third generation cephalosporins . Piperacillin/tazobactam proved to be highly susceptible, the number of the isolates resistant and moderately resistant to it being 6 and 1 per cent respectively . The results showed that cefepime was intermediate between the third generation cephalosporins and carbapenems.

Circulation, 2000 Dec 12, 102(24), 2919 - 22
Transfer of CD4(+) T cells aggravates atherosclerosis in immunodeficient apolipoprotein E knockout mice; Zhou X et al.; BACKGROUND: Atherosclerosis is associated with immune responses to oxidized lipoproteins and certain microorganisms, but the role of specific immunity has remained unclear . METHODS AND RESULTS: To study the role of immunity in atherosclerosis, we crossed atherosclerosis-prone apoE(-/-) mice with immunodeficient scid/scid mice . The offspring showed a 73% reduction in aortic fatty streak lesions when compared with immunocompetent apoE(-/-) mice . Transfer of CD4(+) T cells from apoE(-/-) to immunodeficient apoE(-/-)/scid/scid mice increased lesions by 164% . This was associated with the infiltration of transferred T cells into lesions, increased circulating interferon-gamma levels, and increased I-A expression in lesions . CONCLUSIONS: CD4(+) T cells carry disease-promoting immunity in atherosclerosis.

Stroke, 2000 Dec, 31(12), 2930 - 5
Chlamydia pneumoniae does not influence atherosclerotic plaque behavior in patients with established carotid artery stenosis; Gibbs RG et al.; BACKGROUND AND PURPOSE: Research for infectious agents in the etiology of atherosclerosis has identified Chlamydia pneumoniae as a possible candidate . While there is evidence of an association between presence of this microorganism and atherosclerosis, it is unclear whether infection has a genuinely etiologic role in this disease, whether its presence influences clinical outcomes, and, if so, at which stages of disease this occurs . We have approached this issue in patients with advanced carotid artery atherosclerosis using molecular biological detection methods and clinically relevant indicators of pathology in carotid artery atheroma to determine whether the presence of C pneumoniae correlates with plaque instability . METHODS: C pneumoniae was detected with the use of a sensitive nested polymerase chain reaction . Preoperative embolization and preoperative infarcts were recorded with the use of transcranial Doppler insonation of the middle cerebral artery and cerebral CT, respectively . RESULTS: C pneumoniae DNA was detected in 25.5% of a cohort of 98 symptomatic patients . There was no significant difference in plaque stability as measured by embolization rates between the chlamydial-positive and -negative specimens . There was also no correlation between the number of ipsilateral hemispheric infarcts in the territory of the middle cerebral artery and chlamydial status . CONCLUSIONS: This study confirms that C pneumoniae is a common finding in atherosclerotic plaques of the carotid artery but suggests that the presence of the infectious organism has little detectable impact on plaque instability when measured by clinically significant markers . This raises important questions for the rationale of antibiotic therapy in atherosclerosis.

Mol Gen Genet, 1999 Dec, 262(4-5), 772 - 80
Non-LTR retrotransposons with unique integration preferences downstream of Dictyostelium discoideum tRNA genes; Szafranski K et al.; Retrotransposable elements are genetic enti ties which move and replicate within host cell genomes We have previously reported on the structures and ge nomic distributions of two non-long terminal repea (non-LTR) retrotransposons, DRE and Tdd-3, in the eukaryotic microorganism Dictyostelium discoideum DRE elements are found inserted upstream, and Tdd-3 elements downstream, of transfer RNA (tRNA) genes with remarkable position and orientation specificities The data set currently available from the Dictyostelium Genome Project led to the characterisation of two repetitive DNA elements which are related to the D . discoideum non-LTR retrotransposon Tdd-3 in both their structural properties and genomic distributions . It appears from our data that in the D . discoideum genome tRNA genes are major targets for the insertion of mobilised non-LTR retrotransposons . This may be interpreted as the consequence of a process of coevolution, allowing a viable population of retroelements to transpose without being deleterious to the small microbial host genome which carries only short intergenic DNA sequences . A new nomenclature is introduced to designate all tRNA gene-targeted non-LTR retrotransposons (TREs) in the D . discoideum genome . TREs inserted 5' and 3' of tRNA genes are named TRE5 and TRE3, respectively . According to this nomenclature DRE and Tdd-3 are renamed TRE5-A and TRE3-A, respectively . The new retroelements described in this study are named TRE3-B (formerly RED) and TRE3-C.

J Biol Chem, 2000 Jan 14, 275(2), 823 - 7
The cytotoxic plant protein, beta-purothionin, forms ion channels in lipid membranes; Hughes P et al.; Thionins are small cysteine-containing, amphipathic plant proteins found in seeds and vegetative tissues of a number of plant genera . Many of them have been shown to be toxic to microorganisms such as fungi, yeast, and bacteria and also to mammalian cells . It has been suggested that thionins are present in seeds to protect them, and the germinating seedling, from attack by phytopathogenic microorganisms, but the mechanism by which they kill cells remains unclear . Using electrophysiological measurements, we have shown that beta-purothionin from wheat flour can form cation-selective ion channels in artificial lipid bilayer membranes and in the plasmalemma of rat hippocampal neurons . We suggest that the generalized toxicity of thionins is due to their ability to generate ion channels in cell membranes, resulting in the dissipation of ion concentration gradients essential for the maintenance of cellular homeostasis.

Ann Biomed Eng, 1999 Nov-Dec, 27(6), 697 - 711
Development and application of cell-based biosensors; Pancrazio JJ et al.; Biosensors incorporate a biological sensing element that converts a change in an immediate environment to signals conducive for processing . Biosensors have been implemented for a number of applications ranging from environmental pollutant detection to defense monitoring . Biosensors have two intriguing characteristics: (1) they have a naturally evolved selectivity to biological or biologically active analytes; and (2) biosensors have the capacity to respond to analytes in a physiologically relevant manner . In this paper, molecular biosensors, based on antibodies, enzymes, ion channels, or nucleic acids, are briefly reviewed . Moreover, cell-based biosensors are reviewed and discussed . Cell-based biosensors have been implemented using microorganisms, particularly for environmental monitoring of pollutants . Biosensors incorporating mammalian cells have a distinct advantage of responding in a manner that can offer insight into the physiological effect of an analyte . Several approaches for transduction of cellular signals are discussed: these approaches include measures of cell metabolism, impedance, intracellular potentials, and extracellular potentials . Among these approaches, networks of excitable cells cultured on microelectrode arrays are uniquely poised to provide rapid, functional classification of an analyte and ultimately constitute a potentially effective cell-based biosensor technology . Three challenges that constitute barriers to increased cell-based biosensor applications are presented: analytical methods, reproducibility, and cell sources . Possible future solutions to these challenges are discussed.

Biofizika, 1999 Sep-Oct, 44(5), 773 - 95
{Biophysics at the turn of the century: autowaves}; Ivanitskii GR; By the example of the formation of dissipative patterns in Belousov-Zhabotinsky reactions and in population waves of mobile microorganisms, an attempt was made to analyze the development of the "autowave conception" in the last ten years . New results obtained at the Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, were demonstrated . The place of the "autowave conception" among other methods of studying nonlinear cooperative bioprocesses that form the basis of synergism is shown . The review was prepared on the occasion of the 275th anniversary of the Russian Academy of Sciences and the 2nd Biophysical Meeting of Russia.

Srp Arh Celok Lek, 1999 Jul-Aug, 127(7-8), 254 - 7
{Sociopathologic behavior and repeated infection with venereal disease}; Bjekic M et al.; INTRODUCTION: The sexually transmitted diseases (STDs) comprise a large group of infections produced by different microorganisms including spirochetes, bacteria, chlamydia, mycoplasme, protozoa, fungi, parasites, and viruses . A considerable number of sexually transmitted diseases patients are STD repeaters . As reported by Marjanovitsh and Laloshevitsh {2}, in Belgrade, among patients who during the years 1985 and 1986 visited the City Department for Skin and Veneral Diseases, because of syphilis or gonorrhea, 22.8% had these diseases two or more times during their lives (male/female ratio 10:1) . In Richert et al . {6} study over 30% of all patients who in one year visited sexually transmitted diseases clinic in Dade County, Florida, returned with a new infection within 3 years of their index visit . The aim of this study was to test the hypothesis that there is a relationship between antisocial behaviour and repeated STD . MATERIAL AND METHODS: Case-control study was performed in the population of Belgrade, from June 1997 to April 1998 . Participants were recruited among patients attending the City Department for Skin and Venereal Diseases of Belgrade because of sexually transmitted diseases (syphilis, gonorrhea, nongonoccocal urethritis and genital warts) . The group comprised 101 patients who in their personal histories already had STD two or more times . The control group consisted of 210 patients treated at the same institution for micotic diseases, patients who in their personal histories have never had STD or had it only once (13% of controls) . All participants were men aged 20 to 50 years and all were from Belgrade . Data on demographic characteristics, sexual history and sexual behaviour, as well as data on use of sedatives, smoking habit and sport activity, and data on antisocial behaviour (alcohol abuse, prostitution, drug abuse, prosecution for minor and criminal offences) were collected from all participants by an anonymous questionnaire . In the present paper only data on antisocial behaviour are presented . In the analysis of data chi 2 was used . RESULTS: According to the results obtained, STD repeaters in comparison to their controls used more frequently alcohol (17.8%:0.9%) and drug 18.8%:3.8%), had more frequently sex for money (17.8%:2.8%), and were more frequently prosecuted for minor offences (58.4%:24.8%) and criminal offences (24.8%:4.3%) . All these differences were statistically significant (p < 0.01) . DISCUSSION: In the present study STD repeaters consumed alcohol more frequently than their controls, especially hard liquors, and 55.5% of them had used alcohol at the time of STD infection . In the study of Myliueva et al . {4}, 50% of venereal disease patients consumed alcohol now and then and 10% consumed alcohol frequently . Scheidt and Windle {5} found that 60% of alcoholics had at least one sexually transmitted disease as the result of a high number of sexual partners, low use of condoms and practicing sex for drugs or money . Alcohol has depressive effect on the central nervous system, reduces anxiety and increases libido . In this study STD repeaters in comparison with their controls were significantly more frequently drug users (the majority of them inhaled drugs) . In several studies conducted in the USA {7, 8} the increase of gonorrhea and syphilis was related to drug use . Upchurch et al . {9} reported that individuals with repeated episodes of gonorrhea were frequently intravenous drug abusers . Drugs are most frequently used by young people, at ages of the highest sexual activity . While most of the subjects developed sexual disinterest and dysfunction with prolonged crack cocaine use, some of them become more sexually promiscuous and consequently contracted sexually transmitted diseases more often . Inciardi /10/ found that 1/3 of men who had exchanged sex for crack (or for money needed to by crack) had 100 or more sex partners during a 30-day period prior to study recruitment . Cleghorn et al . (ABSTRACT TRUNCAT

Am J Vet Res, 1999 Dec, 60(12), 1531 - 5
Influence of age and parity on the distribution of cells expressing major histocompatibility complex class II, CD4, or CD8 molecules in the endometrium of mares during estrus; Tunon AM et al.; OBJECTIVE: To evaluate effect of age and parity on distribution and number of cells expressing major histocompatibility complex (MHC) class II, CD4, or CD8 molecules in the endometrium of mares during estrus . ANIMALS: 32 gynecologically healthy mares, categorized as young (3 to 8 years; n = 17) or old (9 to 16 years; 15) and nulliparous (n = 6), nulliparous embryo donors (16), or parous (10) . PROCEDURES: Endometrial specimens collected from the uterine body and horns during estrus were stained by use of the avidin-biotin-peroxidase method, using monoclonal antibodies against equine MHC class II, CD4, and CD8 molecules . Labeled cells in the stratum compactum within 5 randomly selected fields at 400x magnification (total area = 0.31 mm2) were counted, and numbers were compared among groups and between locations . RESULTS: Age did not affect cell numbers within the 3 cell subsets examined . Numbers in each subset were higher in the uterine body than in the horns, although the difference was not significant for cells expressing MHC class II . Significantly more cells expressing MHC class II molecules were detected in the uterine body of nulliparous and parous mares than in embryo donors, whereas in the horns, these cells were significantly higher in number only in parous mares . Parity did not affect number of CD4+ or CD8+ cells . CONCLUSIONS AND CLINICAL RELEVANCE: The increased likelihood for endometritis to develop in mares as they age cannot be explained by a decrease in number of cells expressing MHC class II, CD4, or CD8 molecules within the endometrium . However, greater number of cells within these 3 subsets detected in the uterine body, compared with the horns, during estrus suggests a local readiness to act against microorganisms or semen introduced during mating or insemination.

Am J Vet Res, 1999 Dec, 60(12), 1474 - 7
Isolation and characterization of the eighth component of the bovine complement system; Menger M et al.; OBJECTIVE: To isolate and characterize the eighth component of the complement system (C8) in cattle . SAMPLE POPULATION: Fresh plasma obtained from beef cattle . PROCEDURES: Plasma samples were fractionated, using sequential precipitation and ion-exchange and gel-filtration chromatography, to yield C8 . The protein was identified throughout the procedure on the basis of its hemolytic function . Electrophoresis in polyacrylamide gels was used to determine molecular weight and composition of polypeptide chains . Reconstitution of classical and alternative complement pathways was used to characterize the hemolytic function of bovine C8 . RESULTS: The bovine C8 protein consisted of a disulfide-bonded alpha-gamma heterodimer that was noncovalently associated with a beta chain . Apparent molecular weight of the alpha, beta, and gamma chains under reducing conditions were 66, 61, and 23 kd, respectively . In the classical pathway of activation, bovine C8 and the ninth component of the complement system (C9) had species incompatibility with human C8 and C9 on sheep erythrocyte target cells . CONCLUSIONS: A simple 4-step fractionation procedure provided good yield of bovine C8 from plasma . The isolated protein was structurally comparable to C8 from other species . Purified bovine C8 may be useful in functional hemolytic assays to investigate the roles of complement-mediated lysis in the pathogenesis of inflammatory diseases and the killing of susceptible microorganisms.

Mol Ecol, 1999 Nov, 8(11), 1935 - 45
Acetone preservation: a practical technique for molecular analysis; Fukatsu T; In attempts to establish a convenient and reliable method for field collection and archival preservation of insects and their endosymbiotic microorganisms for molecular analysis, acetone, ethanol, and other organic solvents were tested for DNA preservability of the pea aphid Acyrthosiphon pisum and its intracellular symbiotic bacterium Buchnera sp . After 6 months' storage, not only the band of high-molecular-size DNA but also the bands of rRNA were well preserved in acetone, ethanol, 2-propanol, diethyl ether and ethyl acetate . Polymerase chain reaction (PCR) assays confirmed that the DNA of both the insects and their symbionts was well preserved in these solvents . In contrast, methanol and chloroform showed poor DNA preservability . When water-containing series of acetone and ethanol were examined for DNA preservability, acetone was apparently more robust against water contamination than ethanol . Considering that most biological materials contain high amounts of water, acetone may be a more recommendable preservative for DNA analysis than ethanol which has been widely used for this purpose . The DNA of various insects could be preserved in acetone at room temperature in good condition for several years . In addition to the DNA of the host insects, the DNA of their endosymbionts, including Buchnera and other mycetocyte symbionts, Wolbachia, and gut bacteria, was amplified by PCR after several years of acetone storage . The RNA and protein of the pea aphid and its endosymbiont were also preserved for several years in acetone . After 2 years' storage in acetone, proteins of A . pisum could be analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting, and the endosymbiotic bacteria were successfully detected by immunohistochemistry and in situ hybridization on the tissue sections.

J Steroid Biochem Mol Biol, 1999 Nov, 71(1-2), 83 - 90
Biotransformation XLVII: transformations of 5-ene steroids in Fusarium culmorum culture; Kolek T; The course of the transformation of six 5-ene steroids with varying substituents at C-17 or/and C-3: dehydroepiandrosterone (DHEA), 5-androsten-3beta,17beta-diol, 17alpha-methyl-5-androsten-3beta,17beta-diol, 5-androsten-17-one, 5-androsten-3beta-ol and pregnenolone by Fusarium culmorum was investigated . Three substrates with oxygen functions at C-3 and C-17 i.e . DHEA, 5-androsten-3beta,17beta-diol and 17alpha-methyl-5-androsten-3beta,17beta-diol were hydroxylated entirely at 7alpha-axial, allylic position . The mixture of 7alpha-hydroxy- and 7alpha,15alpha-dihydroxyderivatives was formed during the transformation of pregnenolone and 5-androsten-17-one, from the latter 2alpha,7alpha-dihydroxyderivative was also obtained . 7alpha,15alpha- Dihydroxyderivative was the only product isolated from the 5-androsten-3beta-ol post-transformation mixture . The time-course of the DHEA transformation by F . culmorum shows that the substrate induces 7alpha-hydroxylase activity . DHEA was transformed by androstenedione induced F . culmorum cultures to a larger extent than by a noninduced microorganism; the selectivity of the transformation remained unchanged.

Mod Pathol, 1999 Dec, 12(12), 1152 - 7
Alendronate-associated esophageal injury: pathologic and endoscopic features; Abraham SC et al.; Ingestion of alendronate sodium (Fosamax) by osteoporotic patients can be associated with esophagitis and esophageal ulcer . Alendronate can damage the esophagus both by toxicity from the medication itself and by nonspecific irritation secondary to contact between the pill and the esophageal mucosa, similar to other cases of "pill esophagitis." Despite its wide use, the histologic appearances of alendronate-associated esophageal ulceration have not been previously described in detail, nor is this type of medication-induced injury commonly appreciated by pathologists when evaluating biopsies from ulcer sites . We report a series of 10 patients who experienced erosive/ulcerative esophagitis while ingesting alendronate, and describe the associated endoscopic and pathologic features . Biopsies from all patients showed inflammatory exudate and inflamed granulation tissue as characteristic of any ulcer site . Polarizable crystalline foreign material was present in six of 10 biopsies (60%) . Multinucleated giant cells within the inflammatory exudate were present near this crystalline foreign material in three of 10 biopsies (30%) . Adjacent squamous epithelium typically showed active inflammation and a reactive appearance with enlarged, hyperchromatic nuclei . Multinucleated squamous epithelial giant cells were present in two of 10 cases (20%) . Microorganisms were unusual; scattered fungi and/or viral inclusions were present in only two of 10 biopsies (20%) . Recognition of alendronate-associated erosive or ulcerative esophagitis, particularly in postmenopausal women, and communication of this possibility to the clinician can improve patient care.

Appl Environ Microbiol, 2000 Jan, 66(1), 439 - 42
Use of sublimation to prepare solid microbial media with water-insoluble substrates; Alley JF et al.; A method was developed to deposit a visible layer of water-insoluble compounds via sublimation onto the surface of solid media . The compound is sublimed from a heated aluminum dish containing the compound onto the surface of an inverted, ice-cooled, inoculated agar petri dish . The method results in the deposition of a thin, even layer on the agar surface without the use of solvent . After incubation, clearing zones around colonies indicate the presence of compound-degrading microorganisms.

Appl Environ Microbiol, 2000 Jan, 66(1), 339 - 44
A theoretical study on the metabolic requirements resulting from alpha-ketoglutarate-dependent cleavage of phenoxyalkanoates; Muller RH et al.; The etherolytic cleavage of phenoxyalkanoic acids in various bacteria is catalyzed by an alpha-ketoglutarate-dependent dioxygenase . In this reaction, the electron acceptor is oxidatively decarboxylated to succinate, whereas the proper substrate is cleaved by forming the oxidized alkanoic acid and the phenolic intermediate . The necessity of regenerating alpha-ketoglutarate and the consequences for the overall metabolism were investigated in a theoretical study . It was found that the dioxygenase mechanism is accompanied by a significant loss of carbon amounting to up to 62.5% in the assimilatory branch, thus defining the upper limit of carbon conversion efficiency . This loss in carbon is almost compensated for in comparison to a monooxygenase-catalyzed initial step when the dissimilatory efforts of the entire metabolism are included: the yield coefficients become similar . The alpha-ketoglutarate-dependent dioxygenase mechanism has more drastic consequences for microorganisms which are restricted in their metabolism to the first step of phenoxyalkanoate degradation by excreting the phenolic intermediate as a dead-end product . In the case of phenoxyacetate derivatives, the cleavage reaction would quickly cease due to the exhaustion of alpha-ketoglutarate and no growth would be possible . With the cleavage products of phenoxypropionate and phenoxybutyrate herbicides, i.e., pyruvate and succinate(semialdehyde), respectively, as the possible products, the regeneration of alpha-ketoglutarate will be guaranteed for stoichiometric reasons . However, the maintenance of the cleavage reaction ought to be restricted due to physiological factors owing to the involvement of other metabolic reactions in the pool of metabolites . These effects are discussed in terms of a putative recalcitrance of these compounds.

Appl Environ Microbiol, 2000 Jan, 66(1), 219 - 22
Dehalogenation of haloalkanes by Mycobacterium tuberculosis H37Rv and other mycobacteria; Jesenska A et al.; Haloalkane dehalogenases convert haloalkanes to their corresponding alcohols by a hydrolytic mechanism . To date, various haloalkane dehalogenases have been isolated from bacteria colonizing environments that are contaminated with halogenated compounds . A search of current databases with the sequences of these known haloalkane dehalogenases revealed the presence of three different genes encoding putative haloalkane dehalogenases in the genome of the human parasite Mycobacterium tuberculosis H37Rv . The ability of M . tuberculosis and several other mycobacterial strains to dehalogenate haloaliphatic compounds was therefore studied . Intact cells of M . tuberculosis H37Rv were found to dehalogenate 1-chlorobutane, 1-chlorodecane, 1-bromobutane, and 1,2-dibromoethane . Nine isolates of mycobacteria from clinical material and four strains from a collection of microorganisms were found to be capable of dehalogenating 1,2-dibromoethane . Crude extracts prepared from two of these strains, Mycobacterium avium MU1 and Mycobacterium smegmatis CCM 4622, showed broad substrate specificity toward a number of halogenated substrates . Dehalogenase activity in the absence of oxygen and the identification of primary alcohols as the products of the reaction suggest a hydrolytic dehalogenation mechanism . The presence of dehalogenases in bacterial isolates from clinical material, including the species colonizing both animal tissues and free environment, indicates a possible role of parasitic microorganisms in the distribution of degradation genes in the environment.

J Arthroplasty, 1999 Dec, 14(8), 903 - 10
The arthroscopic drainage, irrigation, and débridement of late, acute total hip arthroplasty infections: average 6-year follow-up; Hyman JL et al.; We present our experience with arthroscopy for the treatment of late, acute periprosthetic hip infections in 8 consecutive patients, treated from 1989 to 1994 . After a hip aspiration confirmed the presence of bacterial infection, all patients underwent prompt arthroscopic treatment, which consisted of drainage, lavage, and debridement . Postoperatively, patients were given 2 to 6 weeks of intravenous antibiotics, followed by long-term oral antibiotic suppression . At a mean follow-up of 70 months (range, 29-104 months), no recurrence of infection occurred . No progressive radiographic loosening was noted . Based on this initial study, we believe that arthroscopic irrigation and debridement can benefit well-selected patients who suffer late, acute hip periprosthetic infections . Effective treatment requires early diagnosis, prompt arthroscopic debridement, well-fixed components, a sensitive microorganism, and patient tolerance to and compliance with the antibiotic therapy.

Int Rev Immunol, 1999, 18(1-2), 141 - 80
Superantigens: mechanisms by which they may induce, exacerbate and control autoimmune diseases; Macphail S; Superantigens are polypeptide molecules produced by a broad range of infectious microorganisms which elicit excessive and toxic T-cell responses in mammalian hosts . In light of this property and the fact that autoimmune diseases are frequently the sequelae of microbial infections, it has been suggested that superantigens may be etiologic agents of autoreactive immunological responses resulting in initiation, exacerbation or relapse of autoimmune diseases . This article relates the biology of superantigens to possible mechanisms by which they may exert these activities and reviews the evidence for their roles in various human and animal models of autoimmune disease . Finally, a mechanism of active suppression by superantigen-activated CD4+ T-cells that could be exploited for therapy as well as prophylaxis of human autoimmune diseases is proposed.

Diagn Cytopathol, 2000 Jan, 22(1), 45 - 8
Acid-fast-positive Legionella pneumophila: a possible pitfall in the cytologic diagnosis of mycobacterial infection in pulmonary specimens; Bentz JS et al.; The acid-fast stain is commonly used in the rapid cytologic assessment of bronchoalveolar lavage (BAL) fluid to detect pulmonary mycobacterial infections, particularly in immunocompromised patients . The identification of acid-fast, rod-shaped organisms may be taken as presumptive evidence of such an infection, in the appropriate clinical setting . However, this determination is made less specific by the occasional acid-fast positivity of microorganisms other than mycobacteria . We report on the occurrence of a fatal pneumonia caused by acid-fast positive Legionella pneumophila detected by BAL . This is a potential pitfall in the rapid diagnosis of pulmonary mycobacterial infections .

Diagn Cytopathol, 2000 Jan, 22(1), 11 - 5
Demonstration of parasites in toxoplasma lymphadenitis by fine-needle aspiration cytology: report of two cases; Zaharopoulos P; Two cases of toxoplasma lymphadenitis diagnosed by fine-needle aspiration (FNA) cytology, in which the microorganisms were identified in the cytologic preparations, are presented . The first case was that of an 8-yr-old boy with bilateral cervical lymphadenopathy of 2-mo duration, in which an FNA specimen of one of the lymph nodes in a Papanicolaou-stained smear disclosed a toxoplasma cyst, and in Wright-Giemsa preparation, dispersed tachyzoites and a pseudocyst . The second case was that of a 52-yr-old man with enlargement of a single lymph node in the neck, of 3-mo duration, FNA of which in Wright-Giemsa preparation disclosed numerous tachyzoites dispersed free in exudate, and also within cells, forming pseudocysts . In both cases, immunocytochemistry by the peroxidase method for Toxoplasma gondii antigen was positive . The tachyzoites seen in Wright-Giemsa preparations, when subjected to fluorescence microscopy, emitted autofluorescence, facilitating their identification . While the presence of parasites in toxoplasma lymphadenitis is quite unusual, having been reported occasionally in histologic preparations and only rarely in cytologic FNA materials, our 2 cases suggest that in active disease, tachyzoites may not be so uncommon in FNA specimens . Besides the use of immunocytochemistry in the diagnosis of the disease, air-dried preparations stained by the Wright-Giemsa method are valuable for the demonstration of such parasites through careful search, along with the possible use of fluorescence microscopy .

Tidsskr Nor Laegeforen, 1999 Nov 10, 119(27), 4070 - 2
{Nitric oxide in the nose and paranasal sinuses--respiratory tract physiology in a new perspective}; Djupesland PG et al.; Nitric oxide (NO) has important functions in a variety of physiological and pathophysiological processes in the body, including vasoregulation, haemostasis, neurotransmission, immunity and respiration . The discovery of surprisingly high concentrations of NO in the nasal airway and paranasal sinuses has important implications for the understanding of airway physiology . The high NO levels in the nasal and paranasal airways contribute to the first line defence against microorganisms . Furthermore, autoinhalation of nasal NO may improve pulmonary function and other remote physiological processes . This airborne messenger system represents a new physiological concept of potential clinical importance . However, NO, like several other mediators, has a dualistic function . Airway NO levels are increased in airway inflammations, such as asthma and allergic rhinitis, but is reduced in cystic fibrosis and other conditions with ciliary dysfunction, sinusitis and after exposure to tobacco and alcohol . Consequently, NO may prove valuable as a non-invasive marker in the diagnosis and monitoring of airway pathologies.

FEMS Microbiol Lett, 2000 Jan 1, 182(1), 57 - 62
Peptostreptococcus micros coaggregates with Fusobacterium nucleatum and non-encapsulated Porphyromonas gingivalis; Kremer BH et al.; Coaggregation is one of the potential colonization strategies of oral microorganisms, often involving fimbrial structures in the interactions . In this study, the coaggregation characteristics of the rough and smooth genotypes of the periodontal pathogen Peptostreptococcus micros were compared to investigate the role of the fibril-like structures of the rough genotype in coaggregation . Of the 11 oral species tested, only Fusobacterium nucleatum strains and non-encapsulated Porphyromonas gingivalis strains coaggregated with P . micros . No differences in coaggregation between the smooth type (Sm), the rough type (Rg) and the smooth variant of the Rg type (Rg(Sm)) of P . micros were observed . Heat-stable, periodate-sensitive structures on P . micros appeared to interact with heat- and protease-sensitive structures on F . nucleatum and P . gingivalis . These data indicate that these unimodal coaggregations are not mediated by the proteinaceous fibril-like structures of the Rg genotype, but by carbohydrates present on both genotypes of P . micros.

Am J Health Syst Pharm, 1999 Dec 15, 56 Suppl 5, S5 - 8
Etiology of neutropenia in HIV-infected patients; Jaresko GS; The causes of neutropenia in HIV-infected patients are described, as is the association of absolute neutrophil count (ANC) and the risk of bacterial infections . In patients with HIV infection, neutropenia can result from the disease or related malignancies, drug therapies, or opportunistic infections . HIV can cause neutropenia by directly or indirectly impairing hematopoiesis . Similarly, microorganisms that cause opportunistic infections, such as cytomegalovirus and Mycobacterium avium complex, can infiltrate the bone marrow and cause myelosuppression . Hematologic toxicities of drug therapy targeted against HIV and opportunistic infections, such as zidovudine, cidofovir, foscarnet, ganciclovir, and trimethoprim/sulfamethoxazole, can further reduce blood cell formation . Several retrospective studies are reviewed that examined the relationship between ANC and the development of bacterial infections in patients infected with HIV . Since neutropenia appears to be associated with increased risk of bacterial infections in HIV-infected patients, approaches to shorten or prevent neutropenia in these patients will likely provide substantial clinical benefit.

Pneumologie, 1999 Nov, 53(11), 530 - 8
{Pathogenesis of pneumocystis carinii pneumonia}; Hoffken G et al.; Pneumocystis carinii is a ubiquitous fungus and opportunistic resident of the bronchoalveolar lumen of men and a variety of other mammalian species . This microorganism replicates under immunosuppressive conditions, ultimately resulting in lethal pneumonia (PcP) if left untreated . In the past decade, considerable progress has been made concerning the understanding of the underlying pathogenic mechanisms of this infection, mostly with the help of animal models such as SCID (severe combined immunodeficiency) or gene-knock-out mice . Partially conflicting data derived from animal studies lead to the assumption that there is no single relevant model for PcP . The T cell-mediated branch of the immune system is recognised as the major component in the host's ability to resist or overcome an infection with P . carinii . Natural, nonspecific immune mechanisms involving mononuclear phagocytes and elaborating a variety of cytokines and other immunomediators play an important role in initiating the immunoresponse as well as in its effector phase, but it is the CD4+ T lymphocytes which are essential for coordinating the complete eradication of this pathogen . The biological function and immunological effects of antigens expressed on the surface of or secreted by P . carinii organisms is not yet fully known . Hopefully, characterisation of these molecules, clarification of their immunological properties and the evaluation of the interactions between humoral and cellular as well as specific and nonspecific parts of the immune system will lead to new insights into the pathogenesis of P . carinii pneumonia.

Microbes Infect, 1999 Jul, 1(9), 727 - 35
Phagocytosis of microorganisms by means of overshooting pseudopods: where do we stand?
Rittig MG, Wilske B, Krause A.
During the endocytic uptake of particulate material such as microorganisms, the transition from the engulfment step to the internalization step of phagocytosis may be disturbed . Thus, the pseudopods flanking the particles do not close to a phagosome, but lie on top of each other . This uncoupling of pseudopod extension and phagosome formation provides useful information about the regular course of phagocytosis . Experimental models on the phenomena of coiling and overlapping phagocytosis have so far been established with legionellas, spirochetes, trypanosomatids, fungal cells, and zymosan.

Epilepsia, 1999 Dec, 40(12), 1780 - 3
Colitis may be part of the antiepileptic drug hypersensitivity syndrome; Eland IA et al.; PURPOSE: To show that colitis may be part of the antiepileptic hypersensitivity syndrome . METHODS: Description of two case histories . RESULTS: The first patient was a 47-year-old man who developed fever, lymphadenopathy, influenza-like symptoms, facial edema, skin rash and diarrhea after 3 weeks of carbamazepine (CBZ) treatment . Laparotomy because of severe abdominal pain 2 weeks later showed severe colitis with perforations . The second patient was a 41-year-old woman who developed fever, diarrhea, and skin rash 4 weeks after start of CBZ treatment . A colon biopsy confirmed colitis . Stool examinations did not show pathogenic microorganisms, and there was no evidence of Crohn's disease or ulcerative colitis . Both patients had elevated liver enzymes, peripheral eosinophilia, and eosinophils in the infiltrate of the colon . CONCLUSIONS: In view of the close temporal relation between start of CBZ intake and development of colitis, the presence of fever, lymphadenopathy, and rash, and improvement after discontinuation of CBZ, we conclude that the two patients developed an AED hypersensitivity syndrome . Our case histories demonstrate that severe colitis may be part of this syndrome.

Insect Biochem Mol Biol, 1999 Dec, 29(12), 1129 - 42
Molecular cloning of cDNAs encoding a range of digestive enzymes from a phytophagous beetle, Phaedon cochleariae; Girard C et al.; To gain better knowledge of the variety of digestive enzymes in phytophagous coleopteran pests, a sequencing screen of 76 random cDNAs from a gut library from Phaedon cochleariae larvae was performed . The screen yielded 21 cDNAs encoding amino-acid sequences homologous to known digestive enzymes, most of them were cell wall-hydrolysing enzymes . The deduced protein sequences of 7 cDNAs encoding putative alpha-amylase, cysteine proteinase, trypsin, chymotrypsin, cellulase, pectinase and xylanase display all the structural features that characterize these enzymes in other eukaryotic organisms . Except the alpha-amylase and chymotrypsin cDNAs, the other cDNAs probably derive from multigene families . The distribution of the corresponding enzymatic activities at various developmental stages of P . cochleariae was examined . alpha-amylase activity is present in guts of larvae and adults, proteinases are abundant in guts of larvae and adults, but scarce in eggs and larval carcasses, xylanases are present in the guts of larvae and adults, as well as in carcasses of larvae, whereas cellulase and pectinase activities are distributed in larval and adult guts, larval carcasses, and eggs . Only a minor fraction of the cellulases is secreted by microorganisms, suggesting that P . cochleariae synthesizes most of its own cell-wall hydrolysing enzymes . The physiological role of the enzymes is discussed, as well as the significance of these results for pest management strategies involving transgenic plants expressing enzyme inhibitors.

Annu Rev Cell Dev Biol, 1999, 15, 113 - 40
Lymphocyte survival--the struggle against death; Arch RH et al.; Cell proliferation and cell death must be closely regulated to maintain the integrity of the immune system during the lifetime of multicellular organisms . Proliferative expansion of lymphoid cells is required for effective immune responses against invading microorganisms . However, following infection eradication, expanded effector cells must be eliminated to prevent non-adaptive accumulation of cells . Therefore, higher vertebrates have developed an extensive network of signal transduction pathways that allow integration of cell survival and cell death stimuli . This network functions to ensure the controlled activation and expansion of cells during an immune response and the deletion of lymphoid cells that are no longer needed at the end of an immune response . Extracellular signals appear to control both mechanisms . Ultimate responses are integrated through cell surface receptors that are linked to intracellular signaling cascades . These signal transduction pathways converge to regulate cell fate at both transcriptional and post-transcriptional levels . In this review, the role of pathways triggered by TNFR-related molecules that determine the fate of lymphoid cells during development and activation is summarized.

Biochemistry (Mosc), 1999 Nov, 64(11), 1230 - 43
Regulation and physiological role of cyanide-resistant oxidases in fungi and plants; Medentsev AG et al.; Data on the induction and regulation of cyanide-resistant oxidases in eucaryotic microorganisms and higher plants are reviewed . Expression of an alternative oxidase gene can be caused by a decrease in energy charge in cells . Some evidence exists suggesting that cAMP and Ca2+ act as intracellular signals inducing the expression of the alternative oxidase genes . Under certain conditions cells produce alternative oxidases which remain in an inactive state . Activation of the alternative pathway of cell respiration is usually observed when electron transport via cytochromes is inhibited . The physiological role of the alternative oxidase is discussed.

Methods, 2000 Jan, 20(1), 47 - 54
Impact of genomics and genetics on the elucidation of bacterial metabolism; Downs DM et al.; In the last few years, the emergence of complete genome sequences has had profound effects on all fields of biology . While the existence of these genome sequences has served to facilitate experimental work, it has also highlighted the gaps in our knowledge of bacterial metabolism . Our current knowledge of metabolism is primarily the result of data accumulated from decades of study by biochemists and geneticists . In general these studies focused on discrete pathways and their regulation . The technical innovations of the last decade, culminating with the sequencing of complete genomes, provide us with the ability to address the next frontier in physiology, metabolic integration . Herein we describe current approaches that can be used to complement classic genetic approaches and further our understanding of both novel metabolic functions and metabolic integration in microorganisms .

J Protein Chem, 1999 Aug, 18(6), 721 - 8
Ligand-protein interaction in plant seed thiamine-binding proteins . Binding of various thiamine analogues to the sepharose-immobilized buckwheat-seed protein; Rapala-Kozik M et al.; Soluble thiamine-binding proteins occur in microorganisms, some animal tissues, and plant seeds . Their representative, the buckwheat-seed protein, was chosen as a model for chemical studies on the mechanism of ligand-protein interaction in these systems . In this work, in order to refine a concept of the chemical topography of the thiamine-binding center, the buckwheat seed protein was immobilized in Sepharose gel and probed with a new set of thiamine-related compounds . In terms of the standard change of Gibbs free energy on the complex formation, the following energetic contributions were specifically assigned to major structural features of the thiamine molecule: (i) 35-45% to the specific electronic structure of planar, unsaturated thiazolium ring with positive charge asymmetrically delocalized, one half of that contribution being attributable to the S(1) atom, (ii) 11-18% to nitrogen atoms and their electronic coupling within the pyrimidine ring, (iii) 15% to the 4'-amino group, and (iv) less than 10% to the hydroxyethyl chain.

Ann Agric Environ Med, 1999, 6(2), 167 - 70
Allergic alveolitis due to herb dust exposure; Mackiewicz B et al.; We report an episode of allergic alveolitis in a female farmer due to massive exposure to organic dust contaminated with microorganisms during threshing of herbs (thyme) . The patient's medical history, the results of exposure test, inhalation challenge, and bronchoalveolar lavage suggested the diagnosis of allergic alveolitis

Curr Pharm Des, 1999 Dec, 5(12), 1015 - 27
The immune system and the effects of non-volatile anesthetics on neutrophil transmigration through endothelial cell monolayers; Hofbauer R et al.; Inflammation represents the consequence of capillary dilation with accumulation of fluid and transmigration of leukocytes into the surrounding tissue . Leukocytes play a major role in the defense system of the body against invading microorganisms . This defense system has a non-specific branch consisting of granulocytes and macrophages and a specific branch of lymphocytes . Granulocytes release cytotoxic compounds from their intracellular granules into their local environment when encountering microorganisms . This random destruction happens rapidly, but it may also harm healthy tissue of the body . Leukocytes patrol the body by circulating through the blood and lymphatic system ensuring a continuous surveillance which is a prerequisite for an efficient defense . Upon tissue damage and inflammation, leukocytes are recruited from the blood to sites of injury, and this trafficking displays exquisite specificity . In the late 1890 s, Metchnikoff noted the power of certain blood cells to move towards microorganisms and ingest them . In fact, leukocytes adhere to the endothelium of the blood vessels, and subsequently leave the circulation by transmigration through the intercellular junctions of the endothelial cell monolayer . Transmigration is driven by chemoattractants, a process known as diapedesis . Reversible adherence of leukocytes to the endothelium, basement membranes, and other surfaces is an essential event in the establishment of inflammation, whose molecular basis is beginning to be understood . Inflammation may become chronic in many pathophysiologic processes and disease states . In long-term mechanically ventilated critically ill patients, non-volatile anesthetics are needed over a prolonged time period . Perioperative infections are a major cause of morbidity and mortality in critically ill patients . Therefore, the influence of non-volatile anesthetics and opioid agents on the immune system is of high interest . After presentation of the different effectors of the immune system and their fluxes through the body, the aim of this review is to propose a general model of leukocyte transmigration through endothelial cell monolayers . It emphasizes in which way different non-volatile anesthetic drugs may affect the non-specific branch of the immune system, i.e . the leukocyte transmigration through endothelial cell monolayers.

Curr Opin Genet Dev, 1999 Dec, 9(6), 664 - 71
Insights into the evolutionary process of genome degradation; Andersson JO et al.; Studies of noncoding and pseudogene sequence diversity, particularly in Rickettsia, have begun to reveal the basic principles of genome degradation in microorganisms . Increasingly, studies of genes and genomes suggest that there has been an extensive amount of horizontal gene transfer among microorganisms . As this inflow of genetic material does not seem generally to have resulted in genome size expansions, however, degenerative processes must be at the very least as widespread as horizontal gene transfer . The basic principles of gene degradation and elimination that are being explored in Rickettsia are likely to be of major importance for our understanding of how microbial genomes evolve.

Rev Inst Med Trop Sao Paulo, 1999 Sep-Oct, 41(5), 319 - 23
Onychomycosis caused by Scytalidium dimidiatum . Report of two cases . Review of the taxonomy of the synanamorph and anamorph forms of this coelomycete; Lacaz CS et al.; The authors report two cases of onychomycosis in the dystrophic form, one of them involving an HIV-positive patient, provoked by Scytalidium dimidiatum, previously called Scytalidium lignicola . The subject is reviewed from the taxonomic viewpoint, considering the anamorph Hendersonula toruloidea as a synonym of Nattrassia mangiferae, and having Scytalidium dimidiatum as the major synanamorph . According to many mycologists, Scytalidium hyalinum may be a separate species or a hyaline mutant of Scytalidium dimidiatum . Scytalidium lignicola Pesante 1957 was considered to be the type-species of the genus by ELLIS (1971)13 and later to be a "conidial state" of Hendersonula toruloidea by the same author, today known as Nattrassia mangiferae . The microorganism lives only on the roots of certain plants (mainly Platanus and Pinus) . It produces pycnidia and is not considered to be a pathogen, although it is considered as a possible emerging agent capable of provoking opportunistic fungal lesions . The importance of this topic as one of the most outstanding in fungal taxonomy, so likely to be modified over time, as well as its interest in the field of dermatologic mycology, are emphasized.

Vet Microbiol, 1999 Dec, 70(3-4), 239 - 50
Occurrence and characterization of gastric Helicobacter spp . in naturally infected dogs; Cattoli G et al.; Helicobacter-like organisms are frequently observed in the stomach of dogs but the relationship between these microorganisms and gastric pathology has not been clearly established . Different species of helicobacters are known to be present in the canine stomach but their specific prevalence in naturally infected dogs is unknown . The aims of this study were to isolate and characterize helicobacters in canine gastric biopsies, to compare the commonly used tests for the identification of Helicobacter spp . and to determine the occurrence of these species in dogs . Twenty-three out of 25 dogs (92%) were positive for Helicobacter-like organisms in cytological screening . Culture was successful from biopsies of 5/25 dogs . The isolates were analyzed by electron microscopy, biochemical and physiological tests, whole protein analysis and 16S rDNA sequencing . Helicobacter felis was identified in four samples and Helicobacter bizzozeronii in one sample . Only the whole protein analysis in combination with electron microscopy was able to clearly discriminate the two species . Compared to the high prevalence of Helicobacter-like organisms, the occurrence of H . felis and H . bizzozeronii, was low (17 and 4%, respectively) . No Flexispira rappini-like organisms or H . salomonis were detected . Electron microscopy revealed that H . bizzozeronii-like microorganisms were present in three additional biopsies where we were unable to culture any Helicobacter-like organisms . These observations indicate that in the stomach of dogs not all helicobacters are culturable . The unculturable bacteria appeared to be the prevalent ones and may represent different spiral organisms . The presence of distinct helicobacters with different characteristics can reflect different roles in the pathogenesis of canine gastric disease.

J Food Prot, 1999 Dec, 62(12), 1372 - 5
Biological control of postharvest decays of apple can prevent growth of Escherichia coli O157:H7 in apple wounds; Janisiewicz WJ et al.; Fresh cells of the antagonist Pseudomonas syringae at 2.4 x 10(8) CFU/ml inoculated into wounds of 'Golden Delicious' apple prevented Escherichia coli O157:H7 (concentrations ranging from 2.4 x 10(5) to 2.4 x 10(7) CFU/ml) from growing in the wounds . This occurred when the two microorganisms were co-inoculated or inoculation with E . coli O157:H7 was conducted 1 or 2 days after inoculation with the antagonist . In similar tests, application of the commercial formulation of this antagonist prevented the growth of E . coli O157:H7 in wounds when inoculated 1 or 2 days after application of the antagonist . Populations of E . coli O157:H7 in wounds treated with water (control) before inoculation with this pathogen increased approximately 2 log units during the first 48 h after inoculation . These results indicate that biocontrol agents developed for controlling storage decays of fruits may have the additional benefit of preventing the growth of foodborne pathogens in freshly wounded tissue of intact and fresh-cut fruits.

Anal Chem, 1999 Dec 1, 71(23), 5348 - 53
High-resolution capillary isoelectric focusing of complex protein mixtures from lysates of microorganisms; Shen Y et al.; High-resolution capillary isoelectric focusing separations of complex protein mixtures have been obtained for cellular lysates of Saccharomyces cerevisiae, Eschericia coli, and Deinococcus radiodurans . High quality separations are shown to be achievable for total protein concentrations of < 0.1 mg/mL . The separation reproducibility was examined, and the influence of the capillary inner wall coating on resolution investigated using fusedsilica capillaries coated with various hydrophilic polymers including hydroxypropyl cellulose, poly(vinyl alcohol), and linear polyacrylamide . Proteins having an isoelectric point (pI) difference of 0.004 are shown to be separated using a linear carrier ampholyte (linear pH gradient between two electrodes) of 3-10 . Approximately 45 discrete peaks in the pI range of 5-7 were obtained for S . cerevisiae, approximately 80 peaks in the pI range of 4.5-8.5 for E . coli, and approximately 210 peaks in the pI range of 3-8.8 for D . radiodurans.

J Agric Food Chem, 1999 Sep, 47(9), 3905 - 10
Microbial release and degradation of nonextractable anilazine residues; Liebich J et al.; Humic substance fractions obtained from a degraded loess soil taken from a long-term lysimeter experiment with the fungicide anilazine were incubated in aerated liquid cultures together with native soil microorganisms . Biomineralization, remobilization of {U-phenyl-(14)C}anilazine, respectively, its metabolites, and changes of the humic matrix were observed under variable nutrient conditions . Stimulated microbial activity favored the degradation of nonextractable (14)C-anilazine residues . However, nitrogen deficiency enhanced structural changes in the humic substances, which seemed to be used then as a nitrogen source . Along with the microbial degradation of the humic substances, parts of the bound anilazine residues became remobilized . Furthermore with the use of AMD-TLC, dihydroxy anilazine was detected within the nonextractable residues . The portion of rather weak bondings between the soil organic acids and the anilazine residues turned out to be considerably lower in the humic acids fractions than in the fulvic acids fraction.

J Agric Food Chem, 1999 Sep, 47(9), 3457 - 79
Chemistry, nutrition, and microbiology of D-amino acids; Friedman M; Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all L-amino acids to D-isomers and concurrent formation of cross-linked amino acids such as lysinoalanine . Racemization of L-amino acids residues to their D-isomers in food and other proteins is pH-, time-, and temperature-dependent . Although racemization rates of the 18 different L-amino acid residues in a protein vary, the relative rates in different proteins are similar . The diet contains both processing-induced and naturally formed D-amino acids . The latter include those found in microorganisms, plants, and marine invertebrates . Racemization impairs digestibility and nutritional quality . The nutritional utilization of different D-amino acids varies widely in animals and humans . In addition, some D-amino acids may be both beneficial and deleterious . Thus, although D-phenylalanine in an all-amino-acid diet is utilized as a nutritional source of L-phenylalanine, high concentrations of D-tyrosine in such diets inhibit the growth of mice . Both D-serine and lysinoalanine induce histological changes in the rat kidney . The wide variation in the utilization of D-amino acids is illustrated by the fact that whereas D-methionine is largely utilized as a nutritional source of the L-isomer, D-lysine is totally devoid of any nutritional value . Similarly, although L-cysteine has a sparing effect on L-methionine when fed to mice, D-cysteine does not . Because D-amino acids are consumed by animals and humans as part of their normal diets, a need exists to develop a better understanding of their roles in nutrition, food safety, microbiology, physiology, and medicine . To contribute to this effort, this multidiscipline-oriented overview surveys our present knowledge of the chemistry, nutrition, safety, microbiology, and pharmacology of D-amino acids . Also covered are the origin and distribution of D-amino acids in the food chain and in body fluids and tissues and recommendations for future research in each of these areas . Understanding of the integrated, beneficial effects of D-amino acids against cancer, schizophrenia, and infection, and overlapping aspects of the formation, occurrence, and biological functions of D-amino should lead to better foods and improved human health.

J Agric Food Chem, 1999 Aug, 47(8), 3389 - 96
Factors influencing transformation rates and formation of products of phenylurea herbicides in soil; Berger BM; Transformation rates of phenylurea herbicides and their products were measured in native soil, sterile soil, soil suspensions, and soil inoculated with pure cultures of microorganisms . In native soil, transformation rates generally increased with decreasing adsorption of the herbicides, but correlations with adsorption coefficients were poor . In sterile soil, substitution patterns of the compounds influenced transformation rates . In soil suspensions, transformation rates increased with lipophilicity of the herbicides . In sterilized soil inoculated with specific microorganisms, transformation was mainly influenced by substrate specificities of the microorganisms to reactive sites of the phenylureas . In all cases, N-demethylation was an important, but not the only, transformation pathway . The data indicate that transformation rates of phenylureas in soils are affected by several parameters, related to the soil, the compounds, and the type of transformation . Although the results were gained in the laboratory under artificial conditions, they form a basis to establish quantitative structure-reactivity relationships and provide explanations for quality and quantity of the formed products.

J Agric Food Chem, 1999 Aug, 47(8), 3197 - 201
Chromatographic identification of a new flavin derivative in plain yogurt; Gliszczynska A et al.; The presence of flavin derivatives in plain yogurt was assessed by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) . The total amount of flavins in yogurts produced by different companies was variable and oscillated between 150.0 and 218.8 microg/100 g . Riboflavin (RF) was the predominant flavin . Besides RF, flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN), 7alpha-hydroxyriboflavin (7alpha-HRF), 4'- or 5'-D-riboflavin-beta-D-galactoside (RFgal), and traces of 10-formylmethylflavin (10-FMF) and 10-hydroxyethylflavin (10-HEF) have been found . It is known that RFgal may be obtained using enzymes or cultures of different microorganisms, but its presence in foodstuffs has not been demonstrated, yet.

Curr Microbiol, 2000 Feb, 40(2), 135 - 6
News & notes: detection of microorganisms with overall cellulolytic activity; Volokita M et al.; A modification is described of the plate method for the detection of microorganisms with overall cellulolytic activity, including those like Cytophaga, in which the activity is cell bound . Within a few days of incubation colonies of cellulose-degrading bacteria formed holes in discs of lens paper placed on freshly inoculated agar plates.

J Lab Clin Med, 1999 Dec, 134(6), 567 - 76
Use of the plasminogen activation system by microorganisms; Coleman JL et al.; The use of host-derived PAS components by invasive bacteria is an increasingly recognized mechanism for acquisition of extracellular proteolytic activity . This overview summarizes the pertinent contributions to this field and is divided into three parts: (1) the PAS, (2) the interaction of bacteria that produce their own plasminogen activators with the host's PAS, and (3) the interaction of bacteria that do not produce their own plasminogen activators but use plasminogen activators supplied by the host . The significance of these mechanisms in relation to the invasive potentials of the various organisms is discussed.

Protein Sci, 1999 Nov, 8(11), 2355 - 65
Crystal structure analysis of a pentameric fungal and an icosahedral plant lumazine synthase reveals the structural basis for differences in assembly; Persson K et al.; Lumazine synthase catalyzes the penultimate step in the synthesis of riboflavin in plants, fungi, and microorganisms . The enzyme displays two quaternary structures, the pentameric forms in yeast and fungi and the 60-meric icosahedral capsids in plants and bacteria . To elucidate the structural features that might be responsible for differences in assembly, we have determined the crystal structures of lumazine synthase, complexed with the inhibitor 5-nitroso-6-ribitylamino-2,4-pyrimidinedione, from spinach and the fungus Magnaporthe grisea to 3.3 and 3.1 A resolution, respectively . The overall structure of the subunit and the mode of inhibitor binding are very similar in these enzyme species . The core of the subunit consists of a four-stranded parallel beta-sheet sandwiched between two helices on one side and three helices on the other . The packing of the five subunits in the pentameric M . grisea lumazine synthase is very similar to the packing in the pentameric substructures in the icosahedral capsid of the plant enzyme . Two structural features can be correlated to the differences in assembly . In the plant enzyme, the N-terminal beta-strand interacts with the beta-sheet of the adjacent subunit, thus extending the sheet from four to five strands . In fungal lumazine synthase, an insertion of two residues after strand beta1 results in a completely different orientation of this part of the polypeptide chain and this conformational difference prevents proper packing of the subunits at the trimer interface in the icosahedron . In the spinach enzyme, the beta-hairpin connecting helices alpha4 and alpha5 participates in the packing at the trimer interface of the icosahedron . Another insertion of two residues at this position of the polypeptide chain in the fungal enzyme disrupts the hydrogen bonding in the hairpin, and the resulting change in conformation of this loop also interferes with proper intrasubunit contacts at the trimer interface.

Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov, 27(5-6), 469 - 74
The performance and kinetic study of membrane anaerobic system in treating POME . Palm oil mill effluent; Lai LS et al.; The application of the three known kinetic models on MAS (membrane anaerobic system) process treating the POME and the overall MAS treatment efficiency were investigated . The MAS consists of a cross-flow ultrafiltration membrane (Model Micro 240) for solid-liquid separation . Six steady states were attained over a range of mixed liquor suspended solids of 12,681 - 30,460 mg/l . The study showed a good fitting of the Monod Model (91.1%), Contois Model (98.5%) and Chen and Hashimoto Model (95%) for the MAS treating raw POME at organic loadings between 1.5 kgCOD/m3/d to 6.5 kgCOD/m3/d . The growth yield coefficient, Y, was found to be 0,604 kg VSS/kgCOD while the specific microorganism decay rate was 0.099 day(-1) . The k values were in the range of 0,242 to 0.425 mg COD/mg VSS.d and the microm values were between 0.145 to 0.257 day(-1) . Throughout the study, the removal efficiency of COD was 83.2 to 97.97% . The methane production rate was between 0.262 to 0.473 l/g-COD-utilised/d . The MAS treatment efficiency was greatly affected by SRT and OLRs . In the study, membrane fouling and polarization at the membrane surface played a significant role in the formation of the strongly attached cake layer limiting membrane permeability

Microb Ecol, 1999 Oct, 38(3), 225 - 233
Molecular Ecological Analysis of Methanogens and Methanotrophs in Blanket Bog Peat; McDonald IR et al.; Abstract Methane production and methane oxidation potential were measured in a 30 cm peat core from the Moorhouse Nature Reserve, UK . The distribution of known groups of methanogens and methane oxidizing bacteria throughout this peat core was assessed . Using 16S rRNA gene retrieval and functional gene probing with genes encoding key proteins in methane oxidation and methanogenesis, several major groups of microorganisms were detected . Methane production and oxidation was detected in all depths of the peat core . PCR amplification and oligonucleotide probing experiments using DNA isolated from all sections of the peat core detected methanotrophs from the groups Methylosinus and Methylococcus and methanogens from the groups Methanosarcinaceae, Methanococcaceae, and Methanobacteriaceae . 16S rDNA sequences amplified with the Methylosinus-specific primer were shown to have a high degree of identity with 16S rDNA sequences previously detected in acidic environments . However, no methanogen sequences were detected by the probes available in this study in the sections of the peat core (above 7 cm) where the majority of methanogenesis occurred, either because of low methanogen numbers or because of the presence of novel methanogen sequences.http://link.springer-ny.com/link/service/journals/00248/bibs/38n3p225.html</hea

Nippon Rinsho, 1999 Oct, 57(10), 2218 - 22
{Pantothenic acid}; Shimizu S; Pantothenic acid is the antipellagra vitamin essential to many animals for growth and health . It is widely distributed in nature; appreciable amounts are found in liver and some microorganisms . Bound forms of pantothenic acid, such as coenzyme A and 4'-phosphopantetheine, play important roles in various metabolic processes, especially, in fatty acid synthesis and degradation.

Mund Kiefer Gesichtschir, 1999 Sep, 3(5), 242 - 6
{Clinical studies on the pathophysiology of odontogenic abscesses}; Wiese KG et al.; In 26 patients with abscesses in the maxillofacial area, the electrolyte concentrations, pH and osmotic and hydrostatic pressures of the pus fluid were measured and calculated . The main cations identified were sodium (134 +/- 38 mmol/l) and potassium (37 +/- 16 mmol/l) and as anions chloride (183 +/- 46 mmol/l) and bicarbonate (10 +/- 4 mmol/l) . The pH value of the pus liquid was 6.164 +/- 0.233 . The calculated mean osmotic pressure of the pus liquid was 7910 +/- 1455 mm Hg, whereas the measured physical pressure inside the abscess was 49 +/- 13 mm Hg . Both pressure types show time-dependent pressure curves . With time, the real pressure inside the abscess cavity increases, whereas the osmotic pressure decreases . There was no relationship between the two pressure types and the different species of microorganisms responsible for the inflammation . The results of the study reveal that abscesses can be regarded as osmotically active systems, and the mechanism by which the abscess is formed might be as follows . After penetration of virulent microorganisms into the tissue space, the area of acute inflammation is walled off by the collection of inflammatory cells . Destruction of tissue by products of the polymorphonuclear leucozytes takes place and results in liquefactive necrosis and a hypertonic abscess cavity . The inwards-directed flow of tissue fluids into the cavity via the abscess membrane causes volume expansion and generates pressure, two facts that can explain the swelling dynamics and typical symptoms of abscesses in the maxillofacial area.

Biosci Biotechnol Biochem, 1999 Sep, 63(9), 1563 - 8
Selective and continuous degradation of carbazole contained in petroleum oil by resting cells of Sphingomonas sp . CDH-7; Kirimura K et al.; Microbial degradation of carbazole (CA), a model of hard-removal heterocyclic nitrogen compounds contained in petroleum oil, was examined using Sphingomonas sp . CDH-7 isolated from a soil sample by screening for CA-assimilating microorganisms . CDH-7 used CA as a sole source of carbon and nitrogen, and metabolized CA to ammonia via anthranilic acid as an intermediate product . When CDH-7 was cultivated in the medium containing CA at the concentration of 500 mg/l (2.99 mM), CA was completely degraded within 50 h . By the reaction with the resting cells of CDH-7, 500 mg/l of CA was completely degraded within 4 h, with 1.64 mM of ammonia accumulated in the reaction mixture . When CA was added at the concentration of 100 mg/l (0.599 mM) periodically to the reaction mixture ten times, 925 mg/l (5.54 mM) of CA was degraded within 48 h by the resting cells, and 4.50 mM of ammonia was accumulated in the reaction mixture with a 75.1% molar conversion yield based on total CA added . The resting cells could almost completely degrade CA in a two-liquid-phase system which consists of water and organic solvent, even in the presence of 20% (v/v) isooctane, n-hexane, cyclohexane, and kerosene as a model petroleum oil . In the presence of an organic solvent system such as 20% (v/v) pxylene, toluene, and heptanol, however, CA degradation yields decreased.

Biosci Biotechnol Biochem, 1999 Sep, 63(9), 1557 - 62
Inhibition of Candida rugosa lipase by berberine and structurally related alkaloids, evaluated by high-performance liquid chromatography; Grippa E et al.; It is known that certain microorganisms produce extracellular lipase to better colonize the skin and mucosal surfaces . Since different extracts from medicinal plants have anti-lipase activity (Shimura et al., Biosci . Biotechnol . Biochem., 56: 1478-1479, 1992), we examined the effects of selected natural substances on Candida rugosa lipase . In the presence of the compounds under examination, the enzyme was incubated with beta-naphthyl laurate, and beta-naphthol, produced by the enzymatic reaction, was extracted with ethyl acetate and analyzed by reversed phase HPLC, using a C-18 column . Thus, the inhibitory activity was calculated by a proper formula based on the variations of the area under the chromatographic peak of beta-naphthol . The method was validated by analyzing substances with known anti-lipase activity such as saturated fatty acids (C10-16) and tetracycline . Berberine and a number of structurally related alkaloids such as chelidonine, chelerythrine, and sanguinarine appeared active . This property of berberine and sanguinarine is of interest because they are used in pathological conditions in which microbial lipases could play a pathogenic role.

Adv Biochem Eng Biotechnol, 2000, 66, 133 - 84
Biomass quantification by image analysis; Pons MN et al.; Microbiologists have always rely on microscopy to examine microorganisms . When microscopy, either optical or electron-based, is coupled to quantitative image analysis, the spectrum of potential applications is widened: counting, sizing, shape characterization, physiology assessment, analysis of visual texture, motility studies are now easily available for obtaining information on biomass . In this chapter the main tools used for cell visualization as well as the basic steps of image treatment are presented . General shape descriptors can be used to characterize the cell morphology, but special descriptors have been defined for filamentous microorganisms . Physiology assessment is often based on the use of fluorescent dyes . The quantitative analysis of visual texture is still limited in bioengineering but the characterization of the surface of microbial colonies may open new prospects, especially for cultures on solid substrates . In many occasions, the number of parameters extracted from images is so large that data-mining tools, such as Principal Components Analysis, are useful for summarizing the key pieces of information.

Int Arch Occup Environ Health, 1999 Nov, 72(8), 507 - 15
Inflammation markers in nasal lavage, and nasal symptoms in relation to relocation to a newly painted building: a longitudinal study; Wieslander G et al.; INTRODUCTION: There is a need to evaluate possible health effects of ventilation improvements and emissions from new buildings, in longitudinal studies . New methods to study biological effects on the eyes and upper airways are now available . MATERIAL AND METHODS: A longitudinal study was performed on 83 trained social workers in two offices in Uppsala, Sweden . The exposed group (n = 57) moved to a newly redecorated building nearby . Low emitting building material had been used, including a new type of solvent-free water-based paint . The control group (n = 26) worked in the same office during the study period (November 1995 to February 1996) . Hygiene management was carried out in both offices, at the beginning and the end of the investigation . Tear film stability (BUT) was measured . Nasal patency was measured by acoustic rhinometry, and eosinophilic cationic protein (ECP), myeloperoxidase (MPO), lysozyme and albumin were analyzed in nasal lavage fluid (NAL) . RESULTS: The relocation resulted in an increase in the personal outdoor airflow rate from 11 to 22 l/s . Indoor concentrations of terpenes were higher in the new building, and powdering of the new linoleum floor was observed . Measurements showed low levels of volatile organic compounds (VOC), formaldehyde, carbon dioxide (CO(2)), nitrogen dioxide, respirable dust, and microorganisms in the air of all buildings . The move resulted in an increased nasal patency and an increase of ECP and lysozyme in NAL, after adjusting for changes in the control group . No changes were observed for nasal or ocular symptoms . A seasonal effect, with a decrease of ECP, was observed in the control group . CONCLUSSION A well-ventilated office building can be redecorated without any major ocular or nasal effects, or measurable increase of indoor air pollution if low-emitting building materials are selected . In agreement with previous evidence, the improved ventilation flow may explain the increase of nasal patency . The increase of ECP and lysozyme in NAL suggested an inflammatory effect in the new building . Since this building had increased ventilation flow, increased concentrations of terpenes, and powdering from the polish on the new linoleum floor, identification of causative agents was difficult . The hygiene measures did not give any evidence that emissions from the new type of solvent-free water-based paints or building dampness were responsible for the observed nasal effects . Considering the higher emissions of VOC reported from older types of water-based latex paints and solvent-based wall paints, the new type of solvent-free water-based paint seems to be a good choice from the hygiene point of view.

Science, 1999 Dec 10, 286(5447), 2138 - 41
More than 200 meters of lake ice above subglacial Lake Vostok, Antarctica; Jouzel J et al.; Isotope studies show that the Vostok ice core consists of ice refrozen from Lake Vostok water, from 3539 meters below the surface of the Antarctic ice sheet to its bottom at about 3750 meters . Additional evidence comes from the total gas content, crystal size, and electrical conductivity of the ice . The Vostok site is a likely place for water freezing at the lake-ice interface, because this interface occurs at a higher level here than anywhere else above the lake . Isotopic data suggest that subglacial Lake Vostok is an open system with an efficient circulation of water that was formed during periods that were slightly warmer than those of the past 420,000 years . Lake ice recovered by deep drilling is of interest for preliminary investigations of lake chemistry and bedrock properties and for the search for indigenous lake microorganisms . This latter aspect is of potential importance for the exploration of icy planets and moons.

Fungal Genet Biol, 1999 Nov, 28(2), 126 - 34
Disruption of the cyanide hydratase gene in Gloeocercospora sorghi increases its sensitivity to the phytoanticipin cyanide but does not affect its pathogenicity on the cyanogenic plant sorghum; Wang P et al.; The release of hydrogen cyanide (HCN) from preformed cyanogenic compounds in plants such as sorghum is thought to provide a protective barrier against infection by microorganisms . Gloeocercospora sorghi, a fungal pathogen of sorghum, produces the enzyme cyanide hydratase (CHT) which converts HCN to the less toxic compound formamide . There is considerable prior evidence indicating that this mechanism for detoxifying HCN plays an important role in the pathogenicity of G . sorghi on sorghum . In the present study, the CHT gene was made nonfunctional in G . sorghi through transformation-mediated gene disruption . The transformant lacked CHT activity and no reacting polypeptides were detected with CHT-specific antibodies . This CHT mutant was highly sensitive to HCN, confirming that CHT is an HCN detoxifying mechanism, but it retained virulence on sorghum, causing lesions indistinguishable from those caused by the wild-type strain . This result indicates that G . sorghi does not require CHT for pathogenicity on cyanogenic lines of sorghum and suggests that cyanogenic compounds in plants may serve functions other than providing a mechanism of disease resistance .

Curr Opin Clin Nutr Metab Care, 1999 Sep, 2(5), 405 - 11
Gastrointestinal flora and its alterations in critical illness; Marshall JC; The normal indigenous flora of the human gastrointestinal tract comprises a remarkably complex yet stable colony of more than 400 separate species, living in a symbiotic relationship with the human host . Stability of that flora is accomplished by multiple mechanisms including gastric acidity, gut motility, bile, products of immune cells in the gut epithelium, and competition between microorganisms for nutrients and intestinal binding sites . The indigenous flora influences multiple aspects of physiologic homeostasis and forms a key component of normal host defenses against infection by exogenous pathogens . Critical illness is associated with striking changes in patterns of microbial colonization, best described in the oropharynx and upper gastrointestinal tract . Pathological colonization occurs with the same species that is predominate in nosocomial infections, and descriptive studies suggest that such colonization is a risk factor for infection . Moreover, prophylactic measures that prevent pathological gut colonization in experimental circumstances reduce rates of nosocomial infection in critically ill patients and, in the case of selective decontamination of the digestive tract, reduce mortality risk . Conventional approaches to infectious diseases have conceptualized microorganisms as inimical and focused on eradicating them as rapidly and fully as possible . Insights from the study of critically ill patients suggest that that relationship is better understood as a symbiotic one and that preservation, rather than elimination, of the indigenous flora provides the greatest promise of clinical benefit to this vulnerable population.

Proc Natl Acad Sci U S A, 1999 Dec 7, 96(25), 14547 - 52
Bacterial diversity within the human subgingival crevice; Kroes I et al.; Molecular, sequence-based environmental surveys of microorganisms have revealed a large degree of previously uncharacterized diversity . However, nearly all studies of the human endogenous bacterial flora have relied on cultivation and biochemical characterization of the resident organisms . We used molecular methods to characterize the breadth of bacterial diversity within the human subgingival crevice by comparing 264 small subunit rDNA sequences from 21 clone libraries created with products amplified directly from subgingival plaque, with sequences obtained from bacteria that were cultivated from the same specimen, as well as with sequences available in public databases . The majority (52.5%) of the directly amplified 16S rRNA sequences were <99% identical to sequences within public databases . In contrast, only 21.4% of the sequences recovered from cultivated bacteria showed this degree of variability . The 16S rDNA sequences recovered by direct amplification were also more deeply divergent; 13.5% of the amplified sequences were more than 5% nonidentical to any known sequence, a level of dissimilarity that is often found between members of different genera . None of the cultivated sequences exhibited this degree of sequence dissimilarity . Finally, direct amplification of 16S rDNA yielded a more diverse view of the subgingival bacterial flora than did cultivation . Our data suggest that a significant proportion of the resident human bacterial flora remain poorly characterized, even within this well studied and familiar microbial environment.

J Periodontol, 1999 Nov, 70(11), 1376 - 82
Bacterial adhesion of Actinobacillus actinomycetemcomitans serotypes to titanium implants: SEM evaluation . A preliminary report; Okte E et al.; BACKGROUND: In this study, the adherence ability of Actinobacillus actinomycetemcomitans serotypes to titanium implant surfaces was evaluated to demonstrate if any selective adherence occurs according to the serotypes of the microorganism . METHODS: The study material included 3 reference strains of A . actinomycetemcomitans serotypes a, b, and c (ATCC 29523, ATCC 43718, ATCC 33384) and 2 clinical isolates of A . actinomycetemcomitans serotypes d and e (IDH 781, IDH 1705), together with commercially available titanium blade implants . For each strain, bacterial suspensions with identical concentrations (5 x 10(7) cells/ml) were prepared and 0.5 ml of each was added on to the implant surfaces, which had been precoated with glycine-bovine serum albumin (BSA) . After incubation at 37 degrees C for 60 minutes in 5% CO2 in air, the implants with attached bacteria were prepared for scanning electron microscopic (SEM) observations . Bacterial adhesion was quantified on the textured body surfaces of the implants, and results were statistically analyzed with analysis of variance followed by Duncan's test . The surface ultrastructure of the bacterial cells was also evaluated descriptively . RESULTS: The tested strains adhered to implant surfaces in different quantities . Serotype a (ATCC 29523) showed the highest adherence affinity (statistically significant, P <0.01) . When compared with each other, serotypes b, c, and d (ATCC 43718, ATCC 33384, and IDH 781) attached equally well, whereas serotype e (IDH 1705) had a statistically significant low adherence capability . CONCLUSIONS: It is suggested that in vitro A . actinomycetemcomitans adhesion to implant surfaces is strain dependent.

J Antimicrob Chemother, 1999 Oct, 44(4), 465 - 9
Amoxycillin/clavulanic acid combinations increase transmigration of leucocytes through endothelial cell monolayers: endothelial cells play a key role; Hofbauer R et al.; Postoperative inflammation is still viewed as an unresolved problem . During inflammation, leucocytes play a tremendous role and migrate from intravascular spaces into the tissue to attack microorganisms . Different agents, e.g . anaesthetic drugs, are able to influence leucocyte recruitment . Previous studies have investigated the influence of amoxycillin on chemotaxis of leucocytes alone . The aim of our study was to examine the effect of amoxycillin/clavulanic acid (co-amoxiclav) on leucocyte migration through endothelial cell monolayers (ECMs) . Human umbilical endothelial cells were cultured on microporous membranes, achieving a monolayer . Polymorphonuclear neutrophil leucocytes (PMNLs) were used in a migration assay . The numbers of untreated PMNLs migrating through untreated ECMs were used as control and set as 100% . PMNLs and/or ECMs were pretreated with co-amoxiclav using clinically relevant as well as higher and lower concentrations . Co-amoxiclav was able to increase PMNL migration through ECMs significantly (P<0.05) when both cell types were treated (291+/-18.7%) . When PMNLs or ECMs were treated alone, it could be shown that ECMs were more affected than PMNLs . The greatest effect was shown when both cell types, PMNLs and ECMs, were treated . In conclusion, co-amoxiclav was identified as a potent drug to increase leucocyte transmigration through ECMs . ECMs were also critically involved . Co-amoxiclav also affects endothelial cells.

J Gastroenterol, 1999 Dec, 34(6), 668 - 74
Helicobacter pylori infection reduces intraluminal nitric oxide in humans; Shiotani A et al.; It has recently been demonstrated that nitric oxide (NO) is highly concentrated in the gastric lumen and plays an important role in defending against pathogenic microorganisms in the stomach . NO in the gastric lumen is mainly delivered by extrinsic sources from saliva . We studied whether Helicobacter pylori infection affected intraluminal NO levels in humans . H . pylori infection was diagnosed on the basis of histology and culture or (13C)-urea breath test . Air and gastric juice in the gastric lumen were collected endoscopically . The concentration of intraluminal NO was measured by a chemiluminescence system, using an NO analyzer . The concentration of nitrite in gastric juice was measured by the Griess reaction . The intraluminal concentration of NO in H . pylori-positive patients (198.2 +/- 41 parts per billion {ppb} mean +/- SE; n = 70) was significantly lower than that in H . pylori-negative patients (353.0 +/-57.9ppb; n = 43; P < 0.05) . In contrast, the concentration of nitrite in gastric juice in H . pylori-positive patients (57.7 +/- 12.3 RM; n = 70) was significantly higher than that in H . pylori-negative patients (25.9 +/- 6.4 microM; n = 43, P < 0.01) . The intraluminal concentration of NO in H . pylori-positive patients was markedly increased and the concentration of nitrite in H . pylori-positive patients was markedly decreased following the completion of eradication therapy . Based on these results, we propose that a decrease in NO and excess nitrite production in the gastric lumen are associated with H . pylori infection and may play an important role in the pathogenesis of H . pylori-related abnormalities.

FEMS Microbiol Lett, 1999 Dec 15, 181(2), 199 - 204
Molecular pathogenesis of the cell surface proteins and lipids from Treponema denticola; Ishihara K et al.; Treponema denticola, frequently isolated from the human oral cavity, is thought to be a major pathogen of human periodontal disease . Recent developments in molecular analysis have clarified the surface structure of this microorganism and the characteristics of its pathogenic factors . Structural analysis of the outer sheath showed T . denticola to have a new type of outer membrane lipid . Limited exposure of the major outer sheath protein is suggested by electron-microscopic analysis . A protease-deficient mutant has revealed the roles of the protease in the organization of the outer sheath material and in T . denticola pathogenicity . The surface features that contribute to the pathogenicity of T . denticola in periodontal disease are gradually being elucidated, and are reviewed.

Klin Khir, 1999, (8), 25 - 7
{The role of microorganisms of the wound in postop complications}; Kholodna LS et al.; Sensitivity of mostly wide-spread pathogenic microorganisms to modern antibiotics of the wide spectrum of action (Tienam, Mefoxin, Cifran), and to antibiotics, widely applied in everyday clinical practice was studied.

Appl Environ Microbiol, 1999 Dec, 65(12), 5510 - 4
Production of sulfur flavors by ten strains of Geotrichum candidum; Berger C et al.; Ten strains of Geotrichum candidum were studied on a liquid cheese model medium for the production of sulfur compounds which contribute to the aroma of cheeses . The volatile components produced by each cultured strain were extracted by dynamic headspace extractions, separated and quantified by gas chromatography (GC), and identified by GC-mass spectrometry . It was shown that four strains of this microorganism produced significant quantities of S-methyl thioacetate, S-methyl thiopropionate, S-methyl thiobutanoate, S-methyl thioisobutanoate, S-methyl thioisovalerate, and S-methyl thiohexanoate . This is the first example of the production of these compounds by a fungus . In addition, dimethyldisulfide, dimethyltrisulfide, dimethylsulfide, and methanethiol, which are more commonly associated with the development of cheese flavor in bacterial cultures, were also produced by G . candidum in various yields, depending on the strain selected . The potential application of these strains in cultured microbial associations to produce modified cheeses with more desirable organoleptic properties is discussed.

Am J Rhinol, 1999 Sep-Oct, 13(5), 335 - 8
Applications of in situ hybridization techniques in the diagnosis of chronic sinusitis; Hwang PH et al.; The clinical significance of positive bacterial cultures in chronic sinusitis is often difficult to assess . Contaminants from surface colonization of the sinus mucosa may be difficult to distinguish from true intramucosal or bone involvement . Furthermore, tissue Gram stains are frequently unable to demonstrate the presence of bacteria in tissue despite endoscopic evidence of active sinusitis . In situ hybridization (ISH) techniques using bacterial rRNA probes were applied to evaluate the presence of intramucosal and intraosseous bacteria in chronic sinusitis surgical specimens . A total of 22 specimens of chronically inflamed human ethmoid bone were evaluated by ISH and by Gram stain . In three specimens, ISH identified bacterial rRNA within sinus mucosa and mucin . Notably, in these three ISH-positive specimens, Gram stain was negative in two . No specimen showed evidence of bacterial rRNA within bone . These preliminary results suggest that in situ hybridization may be a useful adjunct to current methods of detecting microorganisms within chronically infected sinus tissue.

Immunol Res, 1999, 20(2), 117 - 26
The immune system in the elderly: III . Innate immunity; Ginaldi L et al.; The capability to cope with infectious agents and cancer cells resides not only in adaptive immune responses against specific antigens, mediated by T and B lymphocytes clonally distributed, but also in natural immune reactions . These innate defence mechanisms include chemotaxis, phagocytosis, natural cytotoxicity, cell interactions, and soluble mediators or cytokines . However, specific and natural immune mechanisms are always closely linked and interconnected, providing the primary defense against pathogens . The Authors discuss the main changes observed with advancing age in granulocytes and natural killer (NK) cell activity, in the expression and function of adhesion molecules, and in the pattern of cytokine production . Since phagocytic function is the primary mechanism through which the immune system eliminates most extracellular pathogenic microorganisms, analysis of this function is of clinical importance . Neutrophils from aged subjects often exhibit a diminished phagocytic capacity, as well as a depressed respiratory burst, notwithstanding an activated state . The activity of NK cells during aging has been studied extensively and different results have been reported . The most consistent data indicate an increase in cells with high NK activity with advancing age . Cells from healthy centenarians can efficiently kill target cells . This finding seems to suggest that innate immunity and in particular NK cell activity, is not heavily deteriorated with age . Conversely, a low NK activity is a predictor of impending morbidity . Immunosenescence is associated with increased expression of several cell adhesion molecules (CAM) resulting in an augmented capacity to adhere . Finally, also the cytokine network, responsible for differentiation, proliferation, and survival of lymphoid cells, undergoes complex changes with age . The main findings are a Th1 to Th2 cytokine production shift and an increased production of proinflammatory cytokines, which could explain many aspects of age-associated pathological events, such as atherosclerosis and osteoporosis.

Bioorg Med Chem, 1999 Oct, 7(10), 2131 - 8
Purification and characterization of extracellular lipases from Ophiostoma piliferum; Brush TS et al.; Interest in lipases from microorganisms, animals, and plants has greatly increased in the past decade due to their applications in biotransformations and organic syntheses . We are reporting the purification and characterization of two lipases from the fungus, Ophiostoma piliferum, a saprophytic organism commonly found on wood . A major and a minor lipase have been co-purified by hydrophobic interaction chromatography on octyl sepharose FF, followed by ion exchange chromatography on Q sepharose FF . The lipases bound very tightly to octyl sepharose resulting in greater than 100-fold purification in this one step . The major lipase has a molecular weight of approximately 60 kDa, a pI of 3.79, and is glycosylated as determined by PAS staining . The minor lipase, which composes 10% of the total protein, has a pI of 3.6, and molecular weight of approximately 52 kDa and did not stain with the PAS reagent . Deglycosylation of the major lipase produced two proteins of lower molecular weight, a 55 kDa protein and a 52 kDa protein . The deglycosylated protein at 52 kDa co-migrates with the minor lipase on SDS-PAGE gels . N-terminal amino acid sequencing of the major and minor lipases indicated both lipases have the same N-termini and MALDI-TOF mass spectral analysis showed similar peptide patterns . Available data indicate that the lipases are derived from the same protein and appear to differ in their post-translational modification as evidenced by their pIs and molecular weight difference . The pH rate profile and thermal stability were determined for the purified O . piliferum lipase and were consistent with a mesophilic lipase . In aqueous solution, the lipases exhibited a higher rate of hydrolysis for p-nitrophenylbutyrate (C4) than for p-nitrophenylstearate (C18), which is an unexpected result.

Infect Dis Clin North Am, 1999 Dec, 13(4), 851 - 70, vi-vii
Principles and practice of antibiotic therapy; Johnson BS; The oral cavity and surrounding structures harbor an extremely complex array of microorganisms . As a result, when structures become acutely or chronically infected, diseases can present very differently . Surgical and pharmacologic management decisions become equally complex, depending on the source site of the infection and the areas to which it spreads . This article first reviews the various domains of the oral and maxillofacial structures, and then reviews each class of antibiotics, describing how the antibiotics are likely to be used.

Diagn Microbiol Infect Dis, 1999 Oct, 35(2), 105 - 8
Multiplex PCR for rapid and differential diagnosis of Mycoplasma pneumoniae and Chlamydia pneumoniae in respiratory infections; Corsaro D et al.; A duplex polymerase chain reaction (PCR) was developed for the simultaneous detection of Chlamydia pneumoniae and Mycoplasma pneumoniae . A study of 163 respiratory specimens from in-patients of the "Centre Hospitalier et Universitaire de Nancy" showed the good sensitivity of this duplex PCR allowing the detection of C . pneumoniae and M . pneumoniae from 8 and 13 patients, respectively, whereas the culture was negative for C . pneumoniae for all the samples and positive for M . pneumoniae only in 9 cases . The value of these results has been confirmed by running on the same samples specific nested PCRs for these two microorganisms that gave the same results . Thus, the proposed duplex amplification technique may facilitate the diagnosis of infection by these two agents that are difficult to isolate.

Cytometry, 1999 Jan 1, 35(1), 55 - 63
Accurate flow cytometric membrane potential measurement in bacteria using diethyloxacarbocyanine and a ratiometric technique; Novo D et al.; BACKGROUND: Membrane potential (MP) plays a critical role in bacterial physiology . Existing methods for MP estimation by flow cytometry are neither accurate nor precise, due in part to the heterogeneity of size of the particles analyzed . The ratio of a size- and MP-sensitive measurement, and an MP-independent, size-sensitive measurement, should provide a better estimate of MP . METHODS: Flow cytometry and spectrofluorometry were used to detect red (488 --> 600 nm) fluorescence associated with aggregates of diethyloxacarbocyanine (DiOC2(3)), which, in the monomeric state, is normally green (488 --> 530 nm) fluorescent . RESULTS: In bacteria incubated with 30 microM dye, aggregate formation increases with the magnitude of the interior-negative membrane potential . Green fluorescence from stained bacteria predominantly reflects particle size, and is relatively independent of MP, whereas red fluorescence is highly dependent on both MP and size . The ratio of red to green fluorescence provides a measure of MP that is largely independent of cell size, with a low coefficient of variation (CV) . Calibration with valinomycin and potassium demonstrates that the method is accurate over the range from -50 mV through -120 mV; it also accurately tracks reversible reductions in MP produced by incubation at 4 degrees C and washing in glucose-free medium . CONCLUSIONS: The ratiometric technique for MP estimation using DiOC2(3) is substantially more accurate and precise than those previously available, and may be useful in studies of bacterial physiology and in investigations of the effects of antibiotics and other agents on microorganisms.

Int J Pediatr Otorhinolaryngol, 1999 Oct 5, 49 Suppl 1, S223 - 6
Non-specific and specific immunity to bacterial invasion of the middle ear cavity; Stenfors LE; The role of the non-specific (mucociliary clearance, mucus, lactoferrin, lysozyme, fibronectin, lactoperoxidase, complement, phagocytosis) and specific (immunoglobulins) immune systems in combating bacterial pathogens invading the middle ear cavity is discussed . The non-specific system is present from birth, acts promptly against a broad spectrum of microorganisms, has no memory, and is present for life . In contrast, immunoglobulins act specifically . Secretory IgA antibody prevents bacteria from attaching to the epithelium, has no pro-inflammatory effect and does not activate complement . IgG antibodies can opsonize the bacteria for phagocytosis and eventually prevent the bacteria from penetrating the epithelium . IgG is pro-inflammatory and can activate a complement cascade.

Int J Pediatr Otorhinolaryngol, 1999 Oct 5, 49 Suppl 1, S137 - 9
What is wrong in chronic adenoiditis/tonsillitis immunological factor; Agren K et al.; The local immune response in adenoid and tonsil tissue can be visualized and the complexity of the cytokine network and effector molecule expression has not been illustrated in several different tonsillar entities . Many factors still remain to be learned in order to help us to understand the interactions between microorganisms and host in peripheral lymphatic tissue.

Crit Rev Biotechnol, 1999, 19(3), 179 - 96
Cloning of fish enzymes and other fish protein genes; Macouzet M et al.; Fish metabolism needs special enzymes that have maximum activity at very different conditions than their mammalian counterparts . Due to the differences in activity, these enzymes, especially cold-adapted proteases, could be used advantageously for the production of some foods . In addition to the enzymes, this review describes some other unique fish polypeptides such as antifreeze proteins, fluorescent proteins, antitumor peptides, antibiotics, and hormones, that have already been cloned and used in food processing, genetic engineering, medicine, and aquaculture . Recombinant DNA technology, which allows these biological molecules to be cloned and overexpressed in microorganisms is also described, highlighting innovative applications . The expected impact of cloning fish proteins in different fields of technology is discussed.

Pigment Cell Res, 1999 Oct, 12(5), 331 - 9
Location and catalytic characteristics of a multipotent bacterial polyphenol oxidase; Fernandez E et al.; The melanogenic marine bacterium Marinomonas mediterranea contains a multipotent polyphenol oxidase (PPO) able to oxidize substrates characteristic for tyrosinase and laccase . Thus, this enzyme shows tyrosine hydroxylase activity and it catalyzes the oxidation of a wide variety of o-diphenol as well as o-methoxy-activated phenols . The study of its sensitivity to different inhibitors also revealed intermediate features between laccase and tyrosinase . It is similar to tyrosinases in its sensitivity to tropolone, but it resembles laccases in its resistance to cinnamic acid and phenylthiourea, and in its sensitivity to fluoride anion . This enzyme is mostly membrane-bound and can be solubilized either by non-ionic detergent or lipase treatments of the membrane . The expression of this enzymatic activity is growth-phase regulated, reaching a maximum in the stationary phase of bacterial growth, but L-tyrosine, Cu(II) ions, or 2,5-xylidine do not induce it . This enzyme can be separated from a second PPO form by gel permeation chromatography . The second PPO is located in the soluble fraction and shows a sodium dodecyl sulfate (SDS)-activated action on the characteristic substrates for tyrosinase, L-tyrosine, and L-dopa, but it does not show activity towards laccase-specific substrates . The involvement of the multipotent PPO in melanogenesis and its relationship with the SDS-activated form and with the alternative functions proposed for multicopper oxidases in other microorganisms are discussed.

Int J Parasitol, 1999 Aug, 29(8), 1137 - 47
Molecular epidemiology and evolutionary genetics of Leischmania parasites; Banuls AL et al.; In order to illustrate the relevance of the concepts and methods of evolutionary genetics in the understanding of the epidemiology of pathogenic agents, we develop in this paper the case of the Leishmania, a genus of parasitic protozoa . An extensive study of various natural populations of Leishmania in different countries (Old and New World) was carried out by using Multilocus Enzyme Electrophoresis (MLEE) and Random Amplified Polymorphic DNA fingerprinting (RAPD) as genetic markers . The data have been interpreted in evolutionary genetic terms . The main benefit of this approach has been to better define the concept of species in the genus Leishmnania, on rigorous phylogenetic bases . As a matter of fact, a sound taxonomical background is a prerequisite for any epidemiological approach . Since the biological concept of species is difficult or impossible to apply for most pathogenic microorganisms, we recommend relying on criteria of both phylogenetic discreteness and of epidemiological/medical relevance to describe new species of Leishmania . Through this approach, for example, we have shown that the species status of L . ( V.) perzzl.ianza can be supported . On the contrary, we have been unable to clearly distinguish L . (V.) panamensis from L . (V.) guyanensis with genetic tools . Additionally, we have shown that the epidemiological inferences based on a limited set of genetic markers can be misleading . As a matter of fact, we have demonstrated that a collection of L . (L.) infantum stocks identified as zymodeme 'MON 1' by other authors present additional genetic heterogeneity and do not correspond to a distinct 'Discrete Typing Unit' DTU, and are actually polyphyletic . Lastly, in the samples that were conveniently designed, we have confirmed that Leishmania parasites have a basically clonal population structure . As the clonal model specifies it, occasional bouts of genetic exchange remain nevertheless possible . Telling comparisons are drawn with the evolutionary genetics of other pathogens Trypanosoma cruzi and Trypanosoma congolense.

Life Sci, 1999, 65(18-19), 1865 - 74
Chemistry, physiology and pathology of free radicals; Bergendi L et al.; The superoxide anion radical and other reactive oxygen species (ROS) are formed in all aerobic organisms by enzymatic and nonenzymatic reactions . ROS arise in both physiological and pathological processes, but efficient mechanisms have evolved for their detoxification . Similarly, reactive nitrogen intermediates (RNI) have physiological activity, but can also react with different types of molecules, including superoxide, to form toxic products . ROS and RNI participate in the destruction of microorganisms by phagocytes, as in the formation of a myeloperoxidase-hydrogen peroxide-chloride/iodide complex which can destroy many cells, including bacteria . It is known that the cellular production of ROS and RNI is controlled by different mechanisms . These free radicals can react with key cellular structures and molecules, thus altering their biological function . An imbalance between the systems producing and removing ROS and RNI may result in pathological consequences.

Glycobiology, 2000 Jan, 10(1), 59 - 65
C-reactive protein binds to phosphorylated carbohydrates; Culley FJ et al.; C-reactive protein (CRP) is a major acute phase protein in man . In order to more fully understand the physiological role of this serum protein, we have demonstrated high avidity binding for a defined chemically synthesized carbo-hydrate ligand which represents the repeating disaccharide of lipophosphoglycan, the major surface glycoconjugate of the unicellular parasite Leishmania donovani . Increasing the number of phosphorylated disaccharides in a molecule from one up to seven did not increase the avidity for CRP, however increasing this to 10 potential CRP binding sites did . In order to define the important features of this complex and variable structure for CRP binding we competed CRP binding to whole Leishmania parasites with amino, sulfated, phosphorylated, and unsubstituted monosaccharides, of which only phosphorylated monosaccharides were able to inhibit . Both the carbohydrate and the position of phosphorylation influenced the avidity for CRP . Synthetic oligosaccharides and phospho-oligosaccharides of various lengths and conformations were used to define the structural requirements for CRP recognition . The optimum structure for recognition of a single phosphate group was between two monosaccharide pyranose rings, and within a linear rather than a cyclic molecule . This stresses the importance of the interaction of the CRP binding site with both the carbohydrate and the phosphate group . CRP function may be mediated via the recognition of large arrays of phosphorylated carbohydrates as are characteristic of the surface of microorganisms.

Int J Food Microbiol, 1999 Oct 15, 51(2-3), 95 - 103
Thermal inactivation of Alicyclobacillus acidoterrestris spores under different temperature, soluble solids and pH conditions for the design of fruit processes; Silva FM et al.; Alicyclobacillus acidoterrestris, a thermoacidophilic, non-pathogenic and spore-forming bacterium has been detected in several spoiled commercial pasteurised fruit juices . A . acidoterrestris spores, besides being resistant to the pasteurisation treatment conditions normally applied to acidic fruit products, can germinate and grow causing spoilage . Therefore, this microorganism was suggested as the target to be used in the design of adequate pasteurisation processes . The objectives of this work were to investigate the influence of temperature (T: 85-97 degrees C), total soluble solids (SS: 5-60 degrees Brix or % by weight) and pH (2.5-6.0) on D-values (decimal reduction time) of Alicyclobacillus acidoterrestris (type strain, NCIMB 13137) spores, and to fit a model using response surface methodology . A central composite face-centred experimental design was used, and the response, D-value determined in malt extract broth, ranged between 0.498+/-0.045 and 94.9+/-6.7 min . Within the factor ranges studied, temperature was the parameter that most affected the D-value . Following this was the SS and, lastly, the pH value . A linear decrease in D-value was observed with decreasing SS and pH, and a non-linear decrease in D-value was noticed with increasing temperature . A second order polynomial was successfully fitted to the data (R2 = 0.98) . In general, D-values measured in real fruit systems, such as orange, apple and grape juices, blackcurrant concentrates, cupuacu (exotic fruit) extract and orange juice drink, were higher than those predicted by the malt extract broth model . This result emphasises the importance of experimental validation of any model-derived process.

J Nutr, 1999 Dec, 129(12), 2212 - 7
Intestinal microorganisms do not supply associated gnotobiotic rats with conjugated linoleic acid; Kamlage B et al.; Conjugated linoleic acid (CLA) is produced from linoleic acid (LA) by bacteria in the rumen of herbivores . CLA enters the human diet mainly via milk fat and fatty beef; it acts as an effective anticarcinogen and exhibits other important physiological effects . The objective of the current study was to investigate the capability of a LA-conjugating bacterial community isolated from a human volunteer and associated with germ-free rats to supply the host with CLA . Gnotobiotic rats were fed a diet enriched with esterified LA in the form of sunflower-seed oil . The control group was fed the same diet and remained germ-free . Bacterial cell counts, in vitro LA-conjugation activities, and CLA concentration in feces and in the contents of various intestinal segments were determined . After 10 wk, various tissues were analyzed for CLA concentrations . LA-conjugation activity was found only in feces, cecum and colon content samples from associated rats, but CLA accumulation in various body tissues did not differ significantly between the two groups . The ratio of CLA to LA in feces and in cecal and colonic contents did not differ between groups, indicating that the microorganisms in the cecum and the colon do not synthesize substantial amounts of CLA in vivo and therefore, do not contribute to the CLA supplementation of the host.

Int J Food Microbiol, 1999 Nov 1, 52(1-2), 1 - 27
Predictive food microbiology for the meat industry: a review; McDonald K et al.; Predictive food microbiology (PFM) is an emerging multidisciplinary area of food microbiology . It encompasses such disciplines as mathematics, microbiology, engineering and chemistry to develop and apply mathematical models to predict the responses of microorganisms to specified environmental variables . This paper provides a critical review on the development of mathematical modelling with emphasis on modelling techniques, descriptions, classifications and their recent advances . It is concluded that the role and accuracy of predictive food microbiology will increase as understanding of the complex interactions between microorganisms and food becomes clearer . However the reliance of food microbiology on laboratory techniques and skilled personnel to determine process and food safety is still necessary.

Ecotoxicol Environ Saf, 1999 Oct, 44(2), 174 - 81
Influences of copper forms on the toxicity to microorganisms in soils; Kunito T et al.; Soil samples with wide ranges of pH (4.9 to 8.1), organic carbon (0.1 to 77%), and total Cu contents from 32 to 11700 mg kg(-1), collected near a copper mine, were used to investigate the relationships between microbial features and Cu speciation in order to clarify the form(s) of Cu adversely affecting microorganisms . The effects of Cu on soil microorganisms were evaluated by two indicators: the ratio of microbial biomass carbon to soil organic carbon (Cmic/Org-C) and Cu tolerance level of bacterial community (IC50) . The sequential extraction scheme of McLaren and Crawford (1973) was used to quantify the different Cu forms (soluble and exchangeable, specifically adsorbed, and organically bound) . These influences were investigated using simple correlation analysis, multiple regression analysis, and principal component analysis . The IC50 was positively correlated with the log concentration of soluble and exchangeable Cu (Ex-Cu) (r = 0.757, P<0.01) . The IC50 value was also influenced by the amount of specifically adsorbed Cu . The Cmic/Org-C ratio was not significantly correlated with any Cu forms . Thus, other soil properties had more influence on the size of microbial biomass carbon in the soils used . The amount of Ex-Cu exerting high toxicity was affected by pH and the amount of total Cu.

Proc Natl Acad Sci U S A, 1999 Nov 23, 96(24), 13611 - 4
Silver-based crystalline nanoparticles, microbially fabricated; Klaus T et al.; One mechanism of silver resistance in microorganisms is accumulation of the metal ions in the cell . Here, we report on the phenomenon of biosynthesis of silver-based single crystals with well-defined compositions and shapes, such as equilateral triangles and hexagons, in Pseudomonas stutzeri AG259 . The crystals were up to 200 nm in size and were often located at the cell poles . Transmission electron microscopy, quantitative energy-dispersive x-ray analysis, and electron diffraction established that the crystals comprise at least three different types, found both in whole cells and thin sections . These Ag-containing crystals are embedded in the organic matrix of the bacteria . Their possible potential as organic-metal composites in thin film and surface coating technology is discussed.

Prof Dev Ser (Chic Ill) . 1997 May;:1-17; suppl 24 p.
Healthcare environmental services infection control: the basics of microbiology; Otero RB; Support service staff members, regardless of their specific work assignment, frequently come into contact with infected patients and contaminated facility surfaces . Their thorough understanding of the basics of microbiology is critical to the development and implementation of an effective infection control program . Workers who have the benefit of appropriate education as well as the most recent, up-to-date information are positioned to make safe and effective decisions as they go about the task of addressing the many and various environmental situations that occur during the course of the day . These decisions often directly affect the patient care delivery process as well as the quality of its outcomes . The following document provides basic information about the science of microbiology and the disease-producing microorganisms commonly found in a health care facility as well as how those organisms are spread and controlled.

J Agric Food Chem, 1999 Feb, 47(2), 554 - 7
Preparation and characteristics of rumen-bypass microcapsules for improvement of productivity in ruminants; Yoshimaru T et al.; Rumen-bypass microcapsules were prepared by a spray-dry method for protection against microbial hydrogenation in the rumen (neutral pH) . Porous starch was used as the core material, and the microcapsules were prepared by a triple coating of Eudragit E100, AS-HF, and shellac . Capsules were generated with yield of about 48% and a mean particle diameter of 20-30 microm . The microcapsules had high stability in a neutral solution that mimicked a ruminal pH (pH 6.5) . Moreover, when microcapsules were incubated in the presence of ruminal microorganisms, about 65% of the microcapsules were resistant to digestion in ruminal fluids, and protection of the inclusion substance was observed . In addition, the efficiency of release of these microcapsules was about 85% within only 30 min in the abomasal environment (pH 3.0).

J Agric Food Chem, 1999 Feb, 47(2), 524 - 32
Lipid oxidation in fillets of herring (Clupea harengus) during ice storage; Undeland I et al.; The influence of ice storage on lipid oxidation, odor, antioxidants, water-soluble catalysts, and microorganisms was investigated in fillets of herring (Clupea harengus) during 15 days . Based on linear regression analyses of the data, significant rises (p </= 0.05) in lipid oxidation products were seen after 2-3 days and in "rancid" odor after 2.5 days . Peroxide value (PV), fluorescent product (FP), and ascorbic acid analyses were the chemical measures most strongly correlated to "rancid" odor (r = 0.97) . Antioxidants decreased in the following order: alpha-tocopherol > ascorbic acid > glutathione peroxidase (GSH-px); however, GSH-px correlated best to the development of lipid oxidation products (r(mean) = -0.96) . The activity of aqueous pro-oxidants, which were enzymatic in nature to a great extent, had decreased by 75% at day 15 . No significant increase in total bacteria was seen until after 7 days . There were major local differences in both composition and stability throughout the fillet . Oxidation proceeded most rapidly in the tissue right under the skin, probably explained by its high initial pro-oxidative activity.

Nat Cell Biol, 1999 Nov, 1(7), E183 - 8
Controlling the maturation of pathogen-containing vacuoles: a matter of life and death; Meresse S et al.; Once considered to be contained, infectious diseases of bacterial origin are now making a comeback . A lack of innovative therapies and the appearance of drug-resistant pathogens are becoming increasingly serious problems . A better understanding of pathogen-host interactions at the cellular and molecular levels is necessary to define new targets in our fight against microorganisms . In the past few years, the merging of cell biology and microbiology has started to yield critical and often surprising new information on the interactions that occur between various pathogens and their mammalian host cells . Here we focus on the intracellular routing of vacuoles containing microorganisms, as well as on the bacterial effectors and their host-cell targets that control vacuole maturation . We also describe new approaches for isolating microorganism-containing vacuoles and analysing their molecular composition, which will help researchers to define the molecules and mechanisms governing vacuole biogenesis.

Infect Immun, 1999 Dec, 67(12), 6439 - 44
Acquisition of plasmin activity by Fusobacterium nucleatum subsp . nucleatum and potential contribution to tissue destruction during periodontitis; Darenfed H et al.; Fusobacterium nucleatum subsp . nucleatum has been associated with a variety of oral and nonoral infections such as periodontitis, pericarditis, bone infections, and brain abscesses . Several studies have shown the role of plasmin, a plasma serine protease, in increasing the invasive capacity of microorganisms . In this study, we investigated the binding of human plasminogen to F . nucleatum subsp . nucleatum, and its subsequent activation into plasmin . Plasminogen-binding activity of bacterial cells was demonstrated by a solid-phase dot blot assay using an anti-plasminogen antibody . The binding activity was heat resistant and involved cell-surface lysine residues since it was abolished in the presence of the lysine analog epsilon-aminocaproic acid . Activation of plasminogen-coated bacteria occurred following incubation with either streptokinase, urokinase-type plasminogen activator (u-PA), or a Porphyromonas gingivalis culture supernatant . In the case of the P . gingivalis culture supernatant, a cysteine protease was likely involved in the activation . The plasmin activity generated on the cell surface of F . nucleatum subsp . nucleatum could be inhibited by aprotinin . Activation of plasminogen by u-PA was greatly enhanced when plasminogen was bound to bacteria rather than in a free soluble form . u-PA-activated plasminogen-coated F . nucleatum subsp . nucleatum was found to degrade fibronectin, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis . Tissue inhibitor of metalloproteinase-1 was also degraded by the plasmin activity generated on the bacterial cells . This study suggests a possible role for plasminogen, which is present in affected periodontal sites, in promoting tissue destruction and invasion by nonproteolytic bacteria such as F . nucleatum subsp . nucleatum.

Scand J Work Environ Health, 1999 Oct, 25(5), 436 - 41
Meta-analysis of Hodgkin's disease among farmers; Khuder SA et al.; OBJECTIVES: This study examined the association between Hodgkin's disease and farming . METHODS: A series of meta-analyses of peer-reviewed studies was performed, using 30 studies published between 1981 and 1998 . Prior to the meta-analyses, all the studies were reviewed and evaluated for heterogeneity and publication bias . Combined relative risks (RR) were calculated using the random effect model . RESULTS: The combined RR was 1.25 {95% confidence interval (95% CI) 1.11-1.42} for all the studies, and 1.08 (95% CI 0.91-1.29) for the studies involving female farmers . Significant heterogeneity among the studies was detected, and a stratified analysis was carried out by study design, country of study, and time of publication . Significantly elevated RR values were obtained for the case-referent studies (odds ratio 1.53, 95% CI 1.18-1.98) and proportionate mortality studies (PMR)(PMR 1.18, 95% CI 1.02-1.36) . A decrease in risk was eminent in the more recent studies . CONCLUSIONS: The findings suggest that male farmers have a slightly elevated risk of developing Hodgkin's disease . No specific etiologic exposure was identified, but exposures commonly experienced by farmers (infectious microorganisms, herbicides and insecticides) may contribute to the occurrence of the disease.

Immunol Rev, 1999 Aug, 170, 197 - 222
Mucosal immunity and tolerance: relevance to vaccine development; Czerkinsky C et al.; The mucosal immune system of mammals consists of an integrated network of lymphoid cells which work in concert with innate host factors to promote host defense . Major mucosal effector immune mechanisms include secretory antibodies, largely of immunoglobulin A (IgA) isotype, cytotoxic T cells, as well as cytokines, chemokines and their receptors . Immunologic unresponsiveness (tolerance) is a key feature of the mucosal immune system, and deliberate vaccination or natural immunization by a mucosal route can effectively induce immune suppression . The diverse compartments located in the aerodigestive and genitourinary tracts and exocrine glands communicate via preferential homing of lymphocytes and antigen-presenting cells . Mucosal administration of antigens may result in the concomitant expression of secretory immunoglobulin A (S-IgA) antibody responses in various mucosal tissues and secretions, and under certain conditions, in the suppression of immune responses . Thus, developing formulations based on efficient delivery of selected antigens/tolerogens, cytokines and adjuvants may impact on the design of future vaccines and of specific immunotherapeutic approaches against diseases associated with untoward immune responses, such as autoimmune disorders, allergic reactions, and tissue-damaging inflammatory reactions triggered by persistent microorganisms.

FEMS Microbiol Lett, 1999 Dec 1, 181(1), 123 - 9
Phylogenetic relationships of symbiotic spirochetes in the gut of diverse termites; Ohkuma M et al.; Phylogenetic relationships of symbiotic spirochetes in the gut of diverse termites were analyzed without cultivation of these microorganisms . A portion of the 16S rDNA (ca . 850 bp) was amplified directly from DNA of the mixed population in the gut by PCR and cloned . A total of 30 spirochetal phylotypes affiliated with the treponemes were identified from four termite species and they were compared with those already reported from other termites . They represented separate lines of descent from any known species of Treponema, and they were divided into two discrete clusters; one was related to Spirochaeta stenostrepta and S . caldaria, and the other was grouped together with members of the Treponema bryantii subgroup . Although some sequences from evolutionarily related termites showed close similarity, most of the sequences of spirochetes were dissimilar among different termite species, and spirochetal sequences from a single termite species occurred in several distinct phylogenetic positions . These findings suggest that termites constitute a rich reservoir of novel spirochetal diversity and that evolution of the symbiosis is not simple.

J Med Assoc Thai, 1999 Oct, 82(10), 1011 - 6
Comparison of BACTEC automated blood culture system and conventional system in hospitalized pediatric patients; Chokephaibulkit K et al.; A prospective study in pediatric patients compared the BACTEC system, an automated blood culture system using Bactec Ped Plus/F broth media, with the conventional system using Brain Heart Infusion broth media . Each single blood sample drawn for culture from hospitalized children was evaluated by both systems simultaneously . Of 244 pairs of blood samples, 44 (18%) were positive for microorganisms . Of these isolates, 24 (55%) were detected by both systems, 10 (23%) were detected by the BACTEC system only, and 10 (23%) were detected by the conventional system only . The mean turn around time of the BACTEC system (0.56 +/- 0.34, range 0.08-1.55 days) was significantly shorter than that of the conventional system (3.36 +/- 2.72, range 1-7 days, p < 0.001) . Seven isolates strongly suspected to be due to contaminants grew out after 5 days of incubation and were detected by the conventional system only . In this study the BACTEC system and the conventional system were equally effective in detecting microorganisms in the patients' blood samples even if antibiotic therapy had been previously administered . However, the results from the BACTEC system were available much sooner and less likely to be contaminants.

Blood, 1999 Nov 15, 94(10), 3448 - 55
Enhanced liver uptake of opsonized red blood cells after in vivo transfer of FcgammaRIIA cDNA to the liver; Bezdicek P et al.; Fcgamma receptors convey to phagocytic cells the ability to recognize, bind, and internalize IgG-coated cells and microorganisms . The present study demonstrates the use of adenovirus (Ad)-mediated gene transfer of human Fcgamma receptor IIA cDNA to convert normally nonphagocytic cells (hepatocytes) into functional equivalents of phagocytic cells . Ad vector in vitro transfer and expression of FcgammaRIIA cDNA in primary rat hepatocytes was confirmed by flow cytometry anti-FcgammaRIIA immunodetection, and the function of the receptor was demonstrated by enhanced binding and phagocytosis of (51)Cr-labeled IgG-opsonized erythrocytes . After in vivo gene transfer to rats, expression of FcgammaRIIA cDNA in hepatocytes was confirmed by Northern analysis and immunohistochemistry . Rats infected with the Ad vector carrying the FcgammaRIIA cDNA demonstrated enhanced clearance of opsonized erythrocytes, but not nonopsonized erythrocytes, from the circulation with increased sequestration within the liver . Together, these data demonstrate that Ad-mediated FcgammaRIIA gene transfer can convert normally IgG-nonphagocytic cells into phagocytic cells capable of recognizing, binding, and ingesting an opsonized particulate antigen, suggesting that gene transfer strategies might be used to transiently augment host defense by enhancing the clearance of immune complexes.

Arterioscler Thromb Vasc Biol, 1999 Nov, 19(11), 2680 - 6
Chlamydia pneumoniae in abdominal aortic aneurysms: abundance of membrane components in the absence of heat shock protein 60 and DNA; Meijer A et al.; In this article, we describe the results of a comparative study for the detection of Chlamydia pneumoniae in abdominal aortic aneurysm specimens of 19 patients through the use of immunocytochemistry (ICC), in situ hybridization (ISH), and polymerase chain reaction (PCR), along with the detection of cytomegalovirus (CMV) and herpes simplex virus (HSV) by ICC and PCR . C pneumoniae-specific membrane protein was detected in specimens of all 19 (100%; 95% confidence interval {CI} 82% to 100%) and of 15 (79%; 95% CI 54% to 94%) patients with monoclonal antibodies RR-402 and TT-401, respectively . Chlamydial lipopolysaccharide was detected in specimens of 15 (79%; 95% CI 54% to 94%) patients when the results of 4 different monoclonal antibodies were combined . Surprisingly, chlamydial heat shock protein 60 was not detected in any of the specimens by ICC . Furthermore, C pneumoniae DNA was not detected by ISH when a C pneumoniae major outer membrane protein gene fragment was used as probe, nor was it reproducibly detected by PCR on extracted DNA . These results may be explained either by different kinetics of degradation of the different components of C pneumoniae after infection of the vessel wall or by the involvement of other Chlamydia-like microorganisms . Coexistence of C pneumoniae antigens and HSV antigens but not CMV antigens was observed in specimens from 10 of 18 (56%; 95% CI 31% to 78%) patients by ICC . CMV and HSV DNAs were not detected by PCR . In conclusion, we have demonstrated the presence of antigens of C pneumoniae in the absence of specific DNA in abdominal aortic aneurysms, suggesting persistence of the antigens rather than a persistent infection.

Med Klin (Munich), 1999 Oct 15, 94 Suppl 3, 29 - 34
{Expression of selenoproteins in monocytes and macrophages--implications for the immune system}; Ebert-Dumig R et al.; Monocytes differentiate from myeloid precursors towards the macrophage state of differentiation under the influence of 1,25-dihydroxy vitamins D3 (1,25 {OH}2 vitamin D3) and other factors and this is further propagated by colony stimulating factors (MCSF and GMCSF) . Macrophage activation and phagocytosis of foreign particles are regularly accompanied by a so called "respiratory burst", an increase in the production of reactive oxygen species (ROS), exerted by the enzyme complex NADPH oxidase . A number of antioxidant enzymes is expressed at the same time to protect the cells from the cytotoxic effects of ROS directed against engulfed microorganisms . The selenium-dependent glutathione peroxidases and thioredoxin reductases are important examples . The cytosolic GPx isoenzyme (cGPx) and thioredoxin reductase alpha (TrxR alpha) are upregulated during the process of differentiation and under the influence of 1.25 (OH)2 vitamin D3 . GPx isoenzymes neutralize H2O2 . TrxR reduce sulfhydryl-groups like in cysteins either directly or via their cofactor thioredoxin and thus are involved in protein folding and critical protein-protein and protein-DNA interactions, e.g . modulation of dimerization and/or DNA-binding and ligand binding of transcription factors (glucocorticoid receptor and other steroid receptors, NF kappa B) . In addition, the antibiotic peptide NK-lysin was shown to be a substrate for TrxR alpha, suggesting that TrxR protects the cell itself from the cytotoxic effects of NK-lysin . Selenium is incorporated into selenocysteine (Secys) in a regulated fashion in the presence of a hairpin structure (Secis element) in the 3'UTR of selenoprotein genes . Secis elements direct the insertion of Secys at UGA codons, which function as opal stop codons in the absence of a suitable Secis element and in selenium deficiency . The above mentioned processes might therefore be altered in relative selenium deficiency or vice versa be upregulated through selenium supplementation . We have shown that TrxR alpha is a 1.25 (OH)2 vitamin D3-responsive early gene in monocytic cells and that TrxR activity as well as GPx activity in these cells can be upregulated by the addition of selenium in vitro and ex vivo . Recent work demonstrates that thioredoxin rapidly enters the cell nucleus upon treatment of cells with H2O2, but little is known about the compartimentalization of the respiratory burst and the intracellular localization of antioxidant enzymes during that process . Macrophage function is insufficient if the generation of a respiratory burst is altered like in hereditary chronic granulomatous disease on one hand, but on the other hand is as well disturbed, if there is a lack in antioxidant enzyme activity . Thioredoxin has been identified as a lymphocyte growth factor and might therefore be involved in the crosstalk between macrophages and lymphocytes . The relevance of the above mentioned and other yet undefined monocytic selenoproteins remains to be elucidated in detail as well as the relevance of selenium supplementation in nutrition in general and in situations of critical infectious disease and autoimmunity.

Proc Natl Acad Sci U S A, 1999 Nov 9, 96(23), 13330 - 5
Cytokine-mediated Bax deficiency and consequent delayed neutrophil apoptosis: a general mechanism to accumulate effector cells in inflammation; Dibbert B et al.; Neutrophils are important effector cells in immunity to microorganisms, particularly bacteria . Here, we show that the process of neutrophil apoptosis is delayed in several inflammatory diseases, suggesting that this phenomenon may represent a general feature contributing to the development of neutrophilia, and, therefore, in many cases to host defense against infection . The delay of neutrophil apoptosis was associated with markedly reduced levels of Bax, a pro-apoptotic member of the Bcl-2 family . Such Bax-deficient cells were also observed upon stimulation of normal neutrophils with cytokines present at sites of neutrophilic inflammation, such as granulocyte and granulocyte-macrophage colony-stimulating factors, in vitro . Moreover, Bax-deficient neutrophils generated by using Bax antisense oligodeoxynucleotides demonstrated delayed apoptosis, providing direct evidence for a role of Bax as a pro-apoptotic molecule in these cells . Interestingly, the Bax gene was reexpressed in Bax-deficient neutrophils under conditions of cytokine withdrawal . Thus, both granulocyte expansion and the resolution of inflammation appear to be regulated by the expression of the Bax gene in neutrophils.

Trends Biotechnol, 1999 Dec, 17(12), 462 - 5
Treatment of metal-contaminated wastes: why select a biological process?
Eccles H.
Nature has demonstrated some subtle and intricate mechanisms for selectively controlling the mobility of metal pollutants in the environment . However, the application of this science to technology has been disappointing . A small number of pilot-plant studies have been carried out to investigate the potential of microorganisms (primarily bacteria) to remove metals from liquid wastes but only one system in the past 15 years has been commercialized . In order to explain this lack of application, it is important to understand the effectiveness, robustness and reliability of biological processes involving metals and their ability to compete with proven physicochemical technologies.

Arch Surg, 1999 Nov, 134(11), 1243 - 6; discussion 1246-7
Sensitivity and specificity of bronchoalveolar lavage and protected bronchial brush in the diagnosis of pneumonia in pediatric burn patients; Barret JP et al.; BACKGROUND: Infection is still one of the leading causes of death in burn patients . The diagnosis of respiratory tract infection in critically ill burn patients is still difficult . The diagnostic technique of choice remains uncertain, especially because of the lack of a criterion standard by which other diagnostic methods can be compared . HYPOTHESIS: Bronchoalveolar lavage (BAL) and protected bronchial brush (PBB) cultures are not efficacious for the diagnosis of pneumonia in critically ill burn patients . DESIGN: All pediatric patients with burns who died at Shriners Burns Hospital, Galveston, Tex, in the past 10 years were studied . We compared the clinical diagnosis of pneumonia, BAL quantitative culture results, and PBB culture results with autopsy findings . The diagnosis of pneumonia at autopsy was considered the criterion standard, and it was used to calculate the sensitivity and specificity of BAL and PBB cultures . RESULTS: Forty-three patients were studied . Pneumonia was present in 19 (44%) of the 43 autopsies . Pneumonia was diagnosed clinically in 12 (28%) of the 43 patients, and 6 (50%) of them had negative autopsy findings . The sensitivity and specificity of BAL were 56% and 28%, respectively; PBB, 55% and 61%, respectively . The same microorganisms were found at autopsy, in BAL cultures, and in PBB cultures in fewer than 10% of the patients . CONCLUSIONS: Bronchoalveolar lavage and protected bronchial brush have a low sensitivity and specificity and cannot be relied on by themselves for the diagnosis of pneumonia in critically ill burn patients . The results of these sampling techniques must be interpreted in the context of the overall clinical picture of each individual patient.

Cell Tissue Res, 1999 Oct, 298(1), 161 - 6
Secretion of TFF-peptides by human salivary glands; Jagla W et al.; TFF-peptides (formerly P-domain peptides, trefoil factors) are typical secretory products of mucin-producing cells and seem to influence the rheological properties of mucous gels . Here, localization studies of TFF-peptides in human salivary glands are presented . Expression studies (polymerase chain reaction) revealed mainly TFF3 transcripts in submandibular and sublingual glands and trace amounts in parotid glands . Only low levels of expression of TFF1 could be monitored in submandibular and sublingual glands, and TFF2 transcripts were hardly detectable in all three major salivary glands . This result was partly confirmed by Western blot analysis, which only detected TFF3 in submandibular glands, but not in sublingual and parotid glands . TFF3 was also shown to be a constituent of human saliva . Immunofluorescence localized TFF3 solely in the secretory granules of serous cells of submandibular glands but not in mucous cells . This localization is remarkably similar to that of the unique low-molecular-weight mucin MUC7, which interacts with a number of oral microorganisms.

Oral Microbiol Immunol, 1999 Oct, 14(5), 275 - 80
Enhanced interleukin-8 production in THP-1 human monocytic cells by lipopolysaccharide from oral microorganisms and granulocyte-macrophage colony-stimulating factor; Baqui AA et al.; Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been used to assist in bone marrow recovery during cancer chemotherapy . Interleukin-8 (IL-8) plays an important role in macrophage mediated inflammatory processes including exacerbation of periodontal diseases, one of the most common complications in GM-CSF receiving cancer patients . The effect of GM-CSF supplementation on IL-8 production was investigated in a human monocyte cell line THP-1, stimulated with lipopolysaccharide extracted from two oral microorganisms, Porphyromonas gingivalis and Fusobacterium nucleatum . Resting THP-1 cells were treated with lipopolysaccharide (1 microgram/ml) of P . gingivalis or F . nucleatum and/or GM-CSF (50 IU/ml) for varying time periods . The production of IL-8 in THP-1 cells was measured by a solid-phase enzyme-linked immunosorbent assay (ELISA) . A very low level of the cytokine IL-8 was produced constitutive in THP-1 cells . Starting from 8 h of treatment and afterwards GM-CSF alone significantly increased IL-8 production in THP-1 cells . Lipopolysaccharide (1 microgram/ml) extracts from either F . nucleatum or P . gingivalis amplified IL-8 production 500-800 times in comparison to resting THP-1 cells . When lipopolysaccharide of F . nucleatum or P . gingivalis was supplemented with 50 IU/ml of GM-CSF, there was a statistically significant enhanced production of IL-8 by THP-1 cells after 1 day to 7 days of treatment as compared with lipopolysaccharide treatment alone . GM-CSF (50 IU/ml) also significantly increased IL-8 production from 2-7 days of treatment of THP-1 cells when supplemented with a positive control, phorbol-12-myristate-13 acetate (PMA), as compared to PMA treatment alone . These investigations using the in vitro THP-1 human monocyte cell model indicate that there may be an increase in the response on a cellular level to oral endotoxin following GM-CSF therapy as evidenced by enhanced production of the tissue-reactive inflammatory cytokine, IL-8.

Clin Diagn Lab Immunol, 1999 Nov, 6(6), 946 - 52
Specificity and prevalence of natural bovine antimannan antibodies; Srinivasan A et al.; Immune responses to the carbohydrate components of microorganisms, mediated both by antibodies and by lectins, are an important part of host defense . In the present experiments, the specificity and presence of natural bovine antibodies against mannan, a common fungal antigen, were examined by enzyme-linked immunosorbent assay (ELISA), using Saccharomyces cerevisiae mannan as an antigen . The results showed that all serum samples from animals of three age groups (newborn, calf, and adult) tested contained antimannan antibodies, and the titer of these antibodies increased significantly in adults . However, titers among individual adult cattle differed widely . Inhibition assays showed that yeast mannan was the strongest inhibitor . D-Mannose exhibited only a minor inhibitory effect at high concentrations . This suggests that most of these antibodies recognize an oligosaccharide-based epitope(s) different from those recognized by lectins . Cattle possess three serum C-type lectins (collectins) capable of recognizing mannan in a calcium-dependent manner . Addition of EDTA to the reaction did not reduce antibody binding, suggesting that the binding of these antibodies to mannan was not affected by the presence of collectin . The antibodies purified from either calf or adult serum by mannan-Sepharose affinity chromatography consisted of mainly immunoglobulin G (IgG) and a smaller amount of IgM . IgG1 was shown to be the dominant antimannan IgG isotype by isotype-specific ELISA . Together, these results demonstrate the production of natural antimannan antibodies in cattle in an age-dependent manner . These antibodies might be involved in defending the host against mannan-containing pathogens as a specific line of defense in conjunction with the innate response by lectins.

APMIS, 1999 Oct, 107(10), 921 - 8
Experimental corticosteroid induction of Pneumocystis carinii pneumonia in piglets; Nielsen J et al.; Animal models of Pneumocystis carinii (Pc) pneumonia (PCP) play a central role in research on the Pc microorganism itself and the disease, especially the pathogenesis and the host defence . The classic rat model with corticosteroid-induced reactivation of a latent infection has been most widely used . In our search for alternative non-rodent models, six 31/2-week-old piglets were injected intramuscularly with methylprednisolone acetate, at 18 mg/kg body weight, once a week for 6 weeks . Six littermate piglets constituted the control group . The principals showed a markedly lower growth rate than the controls . Furthermore, they developed "moon face" and "pot belly", snoring sounds while eating, and pronounced respiratory distress during handling . Significant changes in haematological parameters, including lymphopenia, were observed in the principal group . The Pc antibody titres of the controls increased to high levels, whereas the principals were all low-titred or seronegative for Pc at the last blood sampling . At necropsy, the mean body weight of the principals was about half that of the controls . In addition, they had an extreme reduction of the thymus together with dark red consolidations of the frontal lung lobes and/or atelectatic looking diaphragmatic lobes . Histopathologically, there was a focal interstitial pneumonia . Alveolar walls and interstitia had mononuclear cell infiltrations and the alveolar lumina were occluded by foamy acidophilic honeycomb material with a varying number of Pc cysts . The reduced body weight, the thymus involution, and the lymphopenia, together with the reduced levels of specific Pc antibodies and the histomorphology of the PCP, were consistent parameters of the principal group and comparable to the findings of the classic rat model . Thus, the present study is the first to describe that prolonged administration of high doses of methylprednisolone acetate can induce PCP in piglets.

Indian J Biochem Biophys, 1999 Feb, 36(1), 39 - 43
n-Propanol as a substrate for assaying the ligninperoxidase activity of Phanerochaete chrysoporium; Shanmugam V et al.; The steady state kinetics of ligninperoxidase catalysed reaction using n-propanol as the organic substrate and monitoring the formation of propanaldehyde at lambda = 300 nm spectrophotometerically as functions of different reaction parameters has been studied . It has been concluded that n-propanol can be used as a substrate for analysing the activity of ligninperoxidase . The turnover number of ligninperoxidase of Phanerochaete chrysosporium using n-propanol as substrate has been found to be higher approximately by a factor of 10(3) as compared to that using veratryl alcohol as the substrate . The method works in assaying the activity of ligninperoxidase produced by Aspergillus fumigatus indicating that it can be used for assaying the ligninperoxidase activities produced by other microorganisms also and is not limited to assaying the ligninase activity produced by Phanerochaete chrysosporium alone . Under identical experimental conditions, horseradish peroxidase does not show peroxidase activity using n-propanol as substrate indicating that the method does not interfere with the activities of other peroxidases.

Arch Tierernahr, 1999, 52(2), 115 - 38
Metabolic functions of L-carnitine and its effects as feed additive in horses . A review; Zeyner A et al.; L-carnitine, a betaine derivative of beta-hydroxybutyrate, is found in virtually all cells of higher animals and also in some microorganisms and plants . In animals it is synthesized almost exclusively in the liver . Two essential amino acids, i.e., lysine and methionine serve as primary substrates for its biosynthesis . Also required for its synthesis are sufficient amounts of vitamin B6, nicotinic acids, vitamin C and folate . The first discovered ergogenic function of L-carnitine is the transfer of activated long-chain fatty acids across the inner mitochondrial membrane into the mitochondrial matrix . For this transfer acyl-CoA esters are transesterified to form acylcarnitine esters . Thus, in carnitine deficiency fat oxidation and energy production from fatty acids are markedly impaired . Skeletal muscles constitute the main reservoir of carnitine in the body and have a carnitine concentration at least 200 times higher than blood plasma . Uptake of carnitine by skeletal muscles takes place by an active transport mechanism which transports L-carnitine into muscles probably in the form of an exchange process with gamma-butyrobetain . In young animals including foals, the capacity for biosynthesis of carnitine is not yet fully developed and apparently cannot meet the requirements of sucking animals . Sucking animals depend therefore on an extra supply of carnitine which is usually provided with milk . Additionally, young animals including foals possess a lower concentration of carnitine in blood plasma than adult animals . Besides its role as carrier of activated acyl groups, L-carnitine functions as a buffer for acetyl groups which may be present in excess in different tissues during ketosis and hypoxic muscular activity . Other functions of L-carnitine are protection of membrane structures, stabilizing of a physiologic CoA-SH/acetyl-CoA ratio and reduction of lactate production . Animal's derived feeds are rich in L-carnitine whereas plants contain usually very little or no carnitine . Carnitine is absorbed from the small intestine by active and passive transport mechanisms . From the increase in renal excretion of L-carnitine after oral supplementations of 10 g/d to horses it has been concluded that the efficiency of absorption of L-carnitine is rather low (about 5 to 10% of the supplied dose) . A further decrease in fractional carnitine absorption was observed when the oral dose of carnitine was increased . L-carnitine is virtually not degraded in the body and renal excretion of carnitine is comparatively small under normal conditions . The concentration of L-carnitine in blood plasma of horses varies markedly between animals and between different days . In addition, circadian changes in carnitine concentration in plasma have been reported . Peak concentrations were found during late afternoon, being up to 30% higher than those in the morning . In breeding mares the carnitine concentration in blood plasma declines with onset of lactation . In resting skeletal muscles about 90% of the total carnitine content is present as free carnitine with the remaining part being available as carnitine esters . With increasing exercise intensity a continuing greater proportion of free carnitine (up to 80%) is converted into carnitine esters, mainly into acetylcarnitine . This shift from free to acetylcarnitine is readily reversed within about 30 min after termination of exercise . It appears that acute exercise does not have a marked effect on the content of total carnitine in skeletal muscle whereas training seems to elevate its total concentration in the middle gluteal muscle of 3 to 6 year old horses and to reduce variation of its concentration compared to age-matched untrained horses . Oral supplementations of 5 to 50 g of L-carnitine per day to horses elevated the carnitine concentration in blood plasma to about twice its basal concentration . No clear relationship existed, however, between the orally administered dose of carnitine and the increase of L-carni

Recent Prog Horm Res, 1999, 54, 133 - 81; discussion 181-3
Neuroendocrinology of infection and the innate immune system; Reichlin S; This chapter deals with two topics: the evolutionary and functional implications of the effects of bacterial endotoxin on the neuroendocrine system in higher vertebrates and a newly recognized neuroendocrine mechanism of immune regulation by the direct secretion of immunoregulatory cytokines from the brain . Endotoxin is a highly specific stimulus to hypothalamic-hypophysial activity; neuroendocrine responses are integrated with behavioral, body temperature, and innate immune responses . All depend upon the genetically programmed capacity of several classes of cells to distinguish molecular patterns foreign to self that are characteristic of pathogenic microorganisms . One component of the response to endotoxin and inflammation in the brain is the direct secretion into the blood (by bulk flow) of appreciable amounts of immunoregulatory cytokines that can modify peripheral levels of IL-6 and TNF-alpha . These can arise from activated glia, endothelia, choroid plexus, and possibly specific neuronal groups . Despite its being an "immune-privileged" organ, brain-presented antigens provoke a greater humoral immune response than by other routes . The capacities of the brain to regulate peripheral cytokine levels by their direct secretion into the blood and to induce antibody response are potential pathways of peripheral neuroimmunomodulation . This mechanism is integrated with the better-established modes of neuroimmunomodulation, sympathetic nervous system, and hypothalamic-pituitary axis.

Gene, 1999 Nov 1, 239(2), 381 - 91
Human phosphoribosylformylglycineamide amidotransferase (FGARAT): regional mapping, complete coding sequence, isolation of a functional genomic clone, and DNA sequence analysis; Patterson D et al.; Purines play essential roles in many cellular functions, including DNA replication, transcription, intra- and extra-cellular signaling, energy metabolism, and as coenzymes for many biochemical reactions . The de-novo synthesis of purines requires 10 enzymatic steps for the production of inosine monophosphate (IMP) . Defects in purine metabolism are associated with human diseases . Further, many anticancer agents function as inhibitors of the de-novo biosynthetic pathway . Genes or cDNAs for most of the enzymes comprising this pathway have been isolated from humans or other mammals . One notable exception is the phosphoribosylformylglycineamide amidotransferase (FGARAT) gene, which encodes the fourth step of this pathway . This gene has been cloned from numerous microorganisms and from Drosophila melanogaster and C . elegans . We report here the identification of a human cDNA containing the coding region of the FGARAT mRNA and the isolation of a P1 clone that contains an intact human FGARAT gene . The P1 clone corrects the purine auxotrophy and protein deficiency of Chinese hamster ovary (CHO) cell mutants (AdeB) deficient in both the activity and the protein for FGARAT . The P1 clone was used to regionally map the FGARAT gene to chromosome region 17p13, a location consistent with our prior assignment of this gene to chromosome 17 . A comparison of the DNA sequence of the human FGARAT and FGARAT DNA sequence from 17 other organisms is reported . The isolation of this gene means that DNA clones for all the 10 steps of IMP synthesis have been isolated from humans or other mammals.

Annu Rev Microbiol, 1999, 53, 71 - 102
Wolbachia pipientis: microbial manipulator of arthropod reproduction; Stouthamer R et al.; The alpha-proteobacterium Wolbachia pipientis is a very common cytoplasmic symbiont of insects, crustaceans, mites, and filarial nematodes . To enhance its transmission, W . pipientis has evolved a large scale of host manipulations: parthenogenesis induction, feminization, and male killing . W . pipientis's most common effect is a crossing incompatibility between infected males and uninfected females . Little is known about the genetics and biochemistry of these symbionts because of their fastidious requirements . The affinity of W . pipientis for the microtubules associated with the early divisions in eggs may explain some of their effects . Such inherited microorganisms are thought to have been major factors in the evolution of sex determination, eusociality, and speciation . W . pipientis isolates are also of interest as vectors for the modification of wild insect populations, in the improvement of parasitoid wasps in biological pest control, and as a new method for interfering with diseases caused by filarial nematodes.

Curr Opin Hematol, 1999 Nov, 6(6), 427 - 31
Storage of blood components; Hogman CF; Recent studies have shown that a restrictive transfusion policy results in lower mortality in patients undergoing surgery . The negative effects of red cell transfusion are associated with the presence of contaminating leukocytes, leukocyte products, and probably also with effects of nonviable and poorly functioning red cells . By relatively simple means it is possible to improve the quality of red cells in these respects . The removal of leukocytes from platelet concentrates (PCs) is even more important because of high immunogenicity and capacity to produce cytokines under the storage conditions applied . Prestorage leukocyte removal has clear advantages . Bacterial contamination of PCs is common, but fatal bacterial complications are rare because most contaminating microorganisms grow slowly and do not produce toxins, which are frequent causes of death . Suitable methods for routine bacterial culture of PCs are available and used in some countries.

Obstet Gynecol, 1999 Nov, 94(5 Pt 1), 787 - 91
Uterine flora at cesarean and its relationship to postpartum endometritis; Sherman D et al.; OBJECTIVE: To evaluate the relationship between the presence of microorganisms at the time of cesarean at different sites of the genital tract and the development of postpartum endometritus . METHODS: One-hundred thirty-three healthy women who delivered by cesarean were enrolled in this prospective study . Cultures were obtained during the surgery and on days 3-5 postoperatively . Gram staining of uterine cavity fluid was done on days 3-5 . Gram stains were examined under a high-power microscope for the presence of polymorphonuclear leukocytes . RESULTS: Twenty patients (15.0%) met the criteria for postpartum endometritis . Forty-five patients (33.8%) had one or more positive cultures (n = 133) at the time of surgery, resulting in 93 positive cultures and 123 bacterial isolates . Forty-four patients had positive postoperative uterine cavity cultures at days 3-5 postpartum, resulting in 65 isolates . Of 44 patients with a positive postoperative culture, 26 (59.1%) also had Gram stain positive for polymorphonuclear leukocytes in the uterine cavity fluid, whereas only six of 89 patients (6.7%) with negative postoperative culture had a positive Gram stain (P < .05) . The relative risk of having a positive culture on postoperative day 3-5 if the culture at surgery was positive at any site was 15.6 (95% confidence interval {CI} 5.9, 42.2), and it was 19.5 (95% CI 6.8, 57.8) if the culture was positive at the lower uterine segment . CONCLUSION: The presence of bacteria in the lower uterine segment at the time of the surgery predicts their presence in the uterine cavity during puerperium . The Gram stain of uterine cavity fluid on postcesarean days 3-5 is another quick tool that can expedite the diagnosis of postpartum endometritis.

Zentralbl Hyg Umweltmed, 1999 Sep, 202(5), 363 - 75
Hygienic monitoring of environmental surroundings in office-based ambulatory surgery units--an instrument for infection control; Christiansen B et al.; Out-patient operations cause lower costs and they are a method the patients are less burdened with than it is the case with usual operating methods . Avoiding nosocomial infections is regarded as another advantage . The rate of infection can be given by a carefully kept nosocomial infection surveillance . Ambulatory surgery units have difficulties in keeping these statistics because they often do not take over the after-treatment of this patients . Out-patient operations in surgeries must guarantee the same standard of hygiene which can usually be found in hospitals . Hospital epidemiologists, health authorities and professional associations have published corresponding guidelines with organizational/functional and structural requirements . These requirements, however, are only met by few ambulatory practices . Surgery holders justify the non-observance of the guidelines by supposing that the spectrum of germs in their office differs from that in a hospital and that there aren't any pathogens . The standard of hygiene in ambulatory surgery units is not controlled regularly . Therefore the hygienic conditions and the microbial burden of five surgeries that carry out out-patient operations under general anaesthesia were determined within the scope of microbial monitoring of the surroundings . Only two surgeries achieved a standard of hygiene which is comparable with that of a hospital . Up to 42% of the taken samples were sterile . The other three surgeries did not meet the requirements . The microbial burden in these surgeries was distinctly higher . The spectrum of detected microorganisms was very wide and there were pathogens too . Hygienic controls and monitoring of the surroundings should be carried out regularly as a measure to guarantee the production and maintenance of quality . Thus the actually achieved hygienic standard in the surgeries can be controlled and improved if necessary . Ambulatory surgeries should be liable to similar hygienic controls as hospitals.

Appl Environ Microbiol, 1999 Nov, 65(11), 4767 - 74
Quantification of syntrophic fatty acid-beta-oxidizing bacteria in a mesophilic biogas reactor by oligonucleotide probe hybridization; Hansen KH et al.; Small-subunit rRNA sequences were obtained for two saturated fatty acid-beta-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYB, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae . S . wolfei LYB was closely related to S . wolfei subsp . wolfei, but S . sapovorans did not cluster with the other members of the genus Syntrophomonas . Five oligonucleotide probes targeting the small-subunit rRNA of different groups within the family Syntrophomonadaceae, which contains all currently known saturated fatty acid-beta-oxidizing syntrophic bacteria, were developed and characterized . The probes were designed to be specific at the family, genus, and species levels and were characterized by temperature-of-dissociation and specificity studies . To demonstrate the usefulness of the probes for the detection and quantification of saturated fatty acid-beta-oxidizing syntrophic bacteria in methanogenic environments, the microbial community structure of a sample from a full-scale biogas plant was determined . Hybridization results with probes for syntrophic bacteria and methanogens were compared to specific methanogenic activities and microbial numbers determined with most-probable-number estimates . Most of the methanogenic rRNA was comprised of Methanomicrobiales rRNA, suggesting that members of this order served as the main hydrogen-utilizing microorganisms . Between 0.2 and 1% of the rRNA was attributed to the Syntrophomonadaceae, of which the majority was accounted for by the genus Syntrophomonas.

Trends Microbiol, 1999 Nov, 7(11), 447 - 53
Pressure-regulated metabolism in microorganisms; Abe F et al.; There has been a renewal of interest in the survival strategies employed by deep-sea, high-pressure-adapted (piezophilic) microorganisms as well as in the effects of high pressure on mesophilic, 1-atmosphere-pressure-adapted microorganisms . This is partly the result of a greater appreciation of the adaptations of microorganisms to life in extreme environments and partly the result of the development of new techniques for examining physiological and molecular processes as a function of pressure.

Lakartidningen, 1999 Oct 6, 96(40), 4315 - 7
{New and re-emergent epidemics in the changing surrounding world}; Iwarson S; In discussion of the emergence of 'new' diseases or the re-emergence of old ones, much attention has been focused on the appearance of hitherto unknown agents versus the transfer of known agents to new populations . The appearance of a new pathogenic microorganism is often assumed to be the result of a change in its genetic properties . Although this may occasionally be the case, in fact most emergent pathogens have already existed in nature . Some occurring in isolated human populations, others well-established in animal species for centuries . Microbial traffic between animals and man is of special interest . Such cross-species transfer of infectious agents is often the result of changes in human behaviour, or in such human activities as deforestation, dam-building and migration.

Support Care Cancer, 1999 Nov, 7(6), 391 - 5
Strategies for prevention of catheter-related bloodstream infections; Sitges-Serra A; Prevention of catheter-related bloodstream infections is critically dependent on an accurate knowledge of the two main routes by which intravascular devices become contaminated: the extraluminal (skin-related) and the intraluminal (hub-related) routes . Extraluminal catheter seeding results from infection of the catheter entry site by microorganisms and leads to bacteremia most often during the week following catheter placement . The main ways of preventing it are appropriate skin disinfection and the adoption of maximal antiseptic barriers at the time of catheter insertion . Avoiding the internal jugular and the femoral veins, whenever possible, will reduce the likelihood of bacteremia . Intraluminal contamination is the consequence of improper handling of the catheter hub at the time of connection and disconnection of the administration set . It is the most common origin of catheter infections after the first week of catheter placement . Multiple-lumen catheters, side-ports and multipurpose catheters particularly increase the risk of endoluminal contamination . To prevent it, strict asepsis should be observed in hub handling and hubs should be protected against environmental soiling with an antiseptic impregnated gauze at all times . New technology is available for prevention of catheter infections: antibiotic and antiseptic-coated catheters, antiseptic hubs, disinfecting caps and flushing solutions are currently undergoing scientific assessment.

Arch Pathol Lab Med, 1999 Nov, 123(11), 1098 - 100
Lack of Epstein-Barr virus infection in cervical carcinomas; Elgui de Oliveira D et al.; CONTEXT: The Epstein-Barr virus (EBV) is a ubiquitous microorganism strongly associated with lymphoproliferative disorders and a large number of human neoplasms, mainly undifferentiated nasopharyngeal carcinoma and Burkitt lymphoma . The viral DNA has been detected in other tumors, such as carcinomas from tonsil, salivary glands, and thymus, and malignancies of the female genital tract . Some authors have proposed that EBV could play a role in the carcinogenesis of cervical tumors; however, other studies do not support this hypothesis . OBJECTIVE: To assess whether EBV is associated with female genital tract neoplasms . DESIGN: Sixty-five biopsy specimens (5 in situ carcinomas, 24 invasive squamous cell carcinomas, 6 lymphoepithelioma-like carcinomas, and 30 endocervical adenocarcinomas) were used to perform EBV detection through RNA in situ hybridization . RESULTS: None of the cervical carcinoma cases studied was positive for EBV infection . CONCLUSIONS: The results suggest that it is still premature to incriminate EBV in the carcinogenesis of cervical carcinoma.

J Investig Dermatol Symp Proc, 1999 Sep, 4(2), 158 - 63
Dendritic cells play a crucial role in innate immunity to simple chemicals; Aiba S et al.; Recently, it has been demonstrated that immunity to infectious agents is composed of innate immunity and acquired immunity, and that dendritic cells (DC) and macrophages, both of which are the participants in the innate immunity, play a crucial role in acquired immune responses, via their expression of several costimulatory molecules and production of cytokines . It is clear that the immune system responds not only to infectious organisms but also to simple chemicals . Allergic contact hypersensitivity reaction is a good example of the immune response to simple chemicals . In contrast to the immunity to microorganisms, however, the role of the innate immune system in responses to simple chemicals still remains unclear . This paper demonstrates that the activation and apoptosis of DC are directly induced by certain simple chemicals, and we suggest that DC, as cells involved in the innate immune system, play a crucial role in the immunity to simple chemicals.

Nucleic Acids Res, 1999 Nov 15, 27(22), 4409 - 15
Markerless gene replacement in Escherichia coli stimulated by a double-strand break in the chromosome; Posfai G et al.; A simple and efficient gene replacement method, based on the recombination and repair activities of the cell, was developed . The method permits the targeted construction of markerless deletions, insertions and point mutations in the Escherichia coli chromosome . A suicide plasmid, carrying the mutant allele and the recognition site of meganuclease I- Sce I, is inserted into the genome by homologous recombination between the mutant and the wild-type (wt) alleles . Resolution of this cointegrate by intramolecular recombination of the allele pair results in either a mutant or a wt chromosome which can be distinguished by allele-specific PCR screening . The resolution process is stimulated by introducing a unique double-strand break (DSB) into the chromosome at the I- Sce I site . Cleavage by the nuclease not only enhances the frequency of resolution by two to three orders of magnitude, but also selects for the resolved products . The DSB-stimulated gene replacement method can be used in recombination-proficient E.coli cells, does not require specific growth conditions, and is potentially applicable in other microorganisms . Use of the method was demonstrated by constructing a 17-bp and a 62-kb deletion in the MG1655 chromosome . Cleavage of the chromosome induces the SOS response but does not lead to an increased mutation rate.

Gastroenterology, 1999 Nov, 117(5), 1113 - 8
Human gastrin: a Helicobacter pylori--specific growth factor; Chowers MY et al.; BACKGROUND & AIMS: Helicobacter pylori resides within the gastric mucosa, a niche hostile to other microorganisms . Human gastrin levels are elevated after infection and return to normal after eradication . The aim of this study was to test the direct effect of gastrin on the growth of H . pylori . METHODS: H . pylori and control bacteria were grown with gastrin or control peptides and growth rate was determined . (125)I-labeled gastrin was used to determine uptake . RESULTS: Human gastrin stimulated H . pylori growth in a specific, dose-dependent manner . Gastrin shortened the lag time, increased growth rate in the logarithmic phase, and increased final bacterial concentration at the stationary phase . These effects were shown over a wide concentration range, including physiological luminal and serum levels . Labeled gastrin uptake was inhibited by unlabeled gastrin . Controls consisting of cholecystokinin and pentagastrin inhibited gastrin uptake but did not stimulate growth . In contrast, somatostatin and epidermal growth factor had no effect on either gastrin uptake or bacterial growth . These results suggest a structurally restricted, receptor-mediated, gastrin-specific effect . CONCLUSIONS: Human gastrin is a specific growth factor for H . pylori and may have a role in the adaptation of H . pylori to its unique habitat.

J Med Microbiol, 1999 Nov, 48(11), 991 - 7
Fine structural characterisation of a Rickettsia-like organism in human platelets from patients with symptoms of ehrlichiosis; Arraga-Alvarado C et al.; Since 1982, Ehrlichia platys infection has been diagnosed in canines from Venezuela by the use of buffy coat smears . In 1992, ehrlichia-like bodies were observed in platelets from a severely ill girl by light microscopy . The patient was seropositive to E . chaffeensis by the indirect fluorescent antibody test (IFAT) . Tetracycline was administered and the patient recovered . More than 400 cases with such intra-platelet organisms have been studied at this laboratory over the past 6 years, and all the patients had a good response to the treatment . To determine whether the organisms in human blood platelets were truly platelet ehrlichiae, IFAT and transmission electron microscopy (TEM) studies were undertaken in four patients . Light microscopic examination of blood samples revealed the dense organism inside platelets, and a great reactivity of the blood cells . Sera from the four patients were seronegative against E . chaffeensis and E . platys antigens . Three of four samples contained the intra-platelet organisms when examined by TEM . Electron microscopy showed platelets with vacuoles containing pleomorphic organisms . These organisms had a thickened membrane, an electron-translucent inner area and an electron-dense granular component in the periphery . An abundant electron-dense material was observed surrounding them . The ultrastructure of such micro-organisms has not been reported previously, Based on the similarity of many of their characteristics with rickettsiae, we suggest that the microorganisms found in the present study might belong to the family Rickettsiaceae.

Sci Total Environ, 1999 Sep 15, 236(1-3), 135 - 52
Indoor air quality at the Correr Museum, Venice, Italy; Camuffo D et al.; Two multidisciplinary field surveys, one in winter and the other in summer have monitored the indoor microclimate, air pollution, deposition and origin of the suspended particulate matter and microorganisms of the Correr Museum, Venice . In addition, this study was focused to identify the problems caused by the heating and air conditioning system (HAC) and the effects due to the presence of carpets . Heating and air conditioning systems (HACs), when chiefly designed for human welfare, are not suitable for conservation and can cause dangerous temperature and humidity fluctuations . Improvements at the Correr Museum have been achieved with the assistance of environmental monitoring . The carpet has a negative influence as it retains particles and bacteria which are resuspended each time people walk on it . The indoor/outdoor pollutants ratio is greater in the summertime, when doors and windows are more frequently open to allow for better ventilation, illustrating that this ratio is mainly governed by the free exchange of the air masses . The chemical composition, size and origin of the suspended particulate matter have been identified, as well as the bacteria potentially dangerous to the paintings . Some general suggestions for improving indoor air quality are reported in the conclusions.

Infect Immun, 1999 Nov, 67(11), 5792 - 8
Invasion of human coronary artery cells by periodontal pathogens; Dorn BR et al.; There is an emerging paradigm shift from coronary heart disease having a purely hereditary and nutritional causation to possibly having an infectious etiology . Recent epidemiological studies have shown a correlation between periodontal disease and coronary heart disease . However, to date, there is minimal information as to the possible disease mechanisms of this association . It is our hypothesis that invasion of the coronary artery cells by oral bacteria may start and/or exacerbate the inflammatory response in atherosclerosis . Since a few periodontal pathogens have been reported to invade oral epithelial tissues, we tested the ability of three putative periodontal pathogens-Eikenella corrodens, Porphyromonas gingivalis, and Prevotella intermedia-to invade human coronary artery endothelial cells and coronary artery smooth muscle cells . In this study we demonstrate by an antibiotic protection assay and electron microscopy that specific species and strains invade coronary artery cells at a significant level . Actin polymerization and eukaryotic protein synthesis in metabolically active cells were required since the corresponding inhibitors nearly abrogated invasion . Many intracellular P . gingivalis organisms were seen to be present in multimembranous vacuoles resembling autophagosomes by morphological analysis . This is the first report of oral microorganisms invading human primary cell cultures of the vasculature.

J Periodontol, 1999 Oct, 70(10), 1185 - 93
Humoral immunity to stress proteins and periodontal disease; Lopatin DE et al.; BACKGROUND: There is evidence that microbial heat shock (stress) proteins (Hsp) are immunodominant antigens of many microorganisms . Immunity to these proteins has been shown in non-oral infections to contribute to protection . This study was undertaken to assess the relationship(s) between immunity to human and microbial heat shock proteins, periodontal disease status, and colonization by periodontal disease-associated microorganisms . METHODS: Subgingival plaque and blood samples obtained from 198 patients during an earlier clinical study were examined for the presence of specific periodontal disease-associated microorganisms and antibodies to selected human and microbial heat shock proteins (Hsp70, Hsp90, DnaK, and GroEL) . Particle concentration immunofluorescence assay (PCFIA) was used to detect anti-Hsp antibodies and slot immunoblot assay (SIB) was used to detect subgingival plaque species . Regression models were used to examine the contribution of age, gender, gingival index, probing depth, attachment loss, calculus index, plaque index, and microbial colonization to the anti-Hsp antibody concentrations . RESULTS: Our studies demonstrated that, when evaluated by ANOVA, patients with higher anti-Hsp (Hsp90, DnaK, and GroEL) antibody concentrations tended to have significantly (P< or =0.05) healthier periodontal tissues . This was most obvious when the relationship between mean probing depths and antibody concentrations were studied . For Hsp90 antibodies, 2 variables (probing depth and P . gingivalis concentration) were found to have significant contributions (R = 0.293, P<0.0002) . The equation derived from the regression model was y = 12558-2070*PD +1842*PG . This confirmed the inverse relationship with probing depth and the positive relationship with colonization by P . gingivalis . Attempts to model the other stress protein antibodies were not successful . CONCLUSIONS: We believe that the present observations reflect the presence of protective anti-Hsp antibodies, rather than simply the presence of the microorganism in the gingival sulcus . The clinical significance of these observations lies in the potential of identifying patients who are at risk for developing periodontal disease based on their inability to mount an immune response to specific Hsp or Hsp epitopes, as well as the development of vaccines based on Hsp epitopes.

Lancet, 1999 Oct 16, 354(9187), 1347 - 51
Effects of mutations in Pneumocystis carinii dihydropteroate synthase gene on outcome of AIDS-associated P . carinii pneumonia; Helweg-Larsen J et al.; BACKGROUND: Sulpha drugs are widely used for the treatment and long-term prophylaxis of Pneumocystis carinii pneumonia (PCP) in HIV-1-infected individuals . Sulpha resistance in many microorganisms is caused by point mutations in dihydropteroate synthase (DHPS), an enzyme that is essential for folate biosynthesis . We assessed whether mutations in the DHPS gene of P . carinii were associated with exposure to sulpha drugs and influenced outcome from PCP . METHODS: We studied bronchoalveolar samples collected in 1989-99 from a prospective cohort of HIV-1-infected patients who had PCP . In 144 patients with 152 episodes of PCP, we analysed portions of DHPS using PCR and direct sequencing . The relation between survival, P . carinii DHPS mutations, and other predictors of treatment failure was assessed by Kaplan-Meier and multivariate Cox regression analysis . FINDINGS: P . carinii DHPS mutations were found in 31 (20.4%) of 152 PCP episodes . 3-month survival was significantly lower in patients infected with mutant P . carinii DHPS strains than in those with wild-type strains (p=0.002) . After adjustment for other prognostic variables, presence of DHPS mutations remained the most important predictor of mortality (hazard ratio 3.1 {95% CI 1.2-8.1}) . DHPS mutations were significantly more common in patients who had previous exposure to sulpha drugs (18 of 29 {62%}) than in those who had no exposure (13 of 123 {10.5%}; p<0.0001) . A significant increase with time in the rate of DHPS mutations (p=0.01 for trend) was closely correlated with the rate of previous or current use of sulpha drugs as chemoprophylaxis . INTERPRETATION: Mutations in DHPS are associated with impaired prognosis in PCP, and may develop as a result of exposure to sulpha drugs.

Adv Biochem Eng Biotechnol, 1999, 65, 23 - 40
Reaction kinetics, molecular action, and mechanisms of cellulolytic proteins; Mosier NS et al.; Cellulolytic proteins form a complex of enzymes that work together to depolymerize cellulose to the soluble products cellobiose and glucose . Fundamental studies on their molecular mechanisms have been facilitated by advances in molecular biology . These studies have shown homology between cellulases from different microorganisms, and common mechanisms between enzymes whose modes of action have sometimes been viewed as being different, as suggested by the distribution of soluble products . A more complete picture of the cellulolytic action of these proteins has emerged and combines the physical and chemical characteristics of solid cellulose substrates with the specialized structure and function of the cellulases that break it down . This chapter combines the fundamentals of cellulose structure with enzyme function in a manner that relates the cellulose binding and biochemical kinetics at the catalytic site of the proteins to the macroscopic behavior of cellulase enzyme systems.

Med Hypotheses, 1999 Aug, 53(2), 91 - 102
Is the pathogen of prion disease a microbial protein?
Fuzi M.
Though considerable circumstantial evidence suggests that the pathogen of prion disease is proteinaceous, it has not yet been conclusively identified . Epidemiological observations indicate that a microbial vector is responsible for the transmission of natural prion disease in sheep and goats and that the real causative agent may correspond to a structural protein of that microorganism . The microbial protein should resemble prion protein (PrP) and may replicate itself in the host by using mammalian DNA . A similar phenomenon was already described with a protein antigen of the ameba Naegleria gruberi . The various serotypes of the microbial protein may account for the existence of scrapie strains . It is proposed that many microbial proteins may be capable of replicating themselves in mammalian cells eliciting and sustaining thereby degenerative and/or autoimmune reactions subsequent to infections with microorganisms.

Rev Gastroenterol Mex, 1999 Apr-Jun, 64(2), 70 - 4
{Microsporidiasis in AIDS patients with chronic diarrhea . Expieriences at the National Institute of Nutrition "Salvador Zubrirán"}; Gamboa Dominguez A et al.; BACKGROUND: Microsporidium sp . has been considered as a rare cause of diarrhea in AIDS patients . However, the improvement of some histochemical stains in the analysis of small bowel biopsies has shown an increase in its prevalence . In Mexico there are no series reporting intestinal microsporidiasis . DESIGN: Small bowel biopsies of 98 patients with AIDS and chronic diarrhea stained with HE and Giemsa were reviewed (January 1987-December 1994) . The clinical, demographic and laboratory information was obtained from the clinical charts . RESULTS: In 50 patients an opportunistic microorganism was identified in the small bowel biopsy (51%) . Microsporidium sp . was identified in 30 patients (31%) . The clinical charts were reviewed in all but six cases . Of the 24 patients with microsporidiasis as the cause of diarrhea, 17 were male and seven female with a median age, of 33 years, old . Homosexuality was the main risk factor in males (11/17), and blood transfusion in females (4/7) . A low socioeconomical classification was found in 75% cases . The initial manifestation of AIDS was diarrhea in 16/24 (67%), CD4 count cell below 200 mm3 was identified in 13/24 patients and more than 200 mm3 in 2/24 . The stool examination and the original histologic interpretations were negative for Microsporidium sp . Lymphoplasmocytic inflammatory infiltrate with eosinophils in the lamina propia and atrophy was frequently seen . A pale red and gray color was observed in spore and merogonial phases of Microsporidium stained with Giemsa . CONCLUSION: Microsporidium sp . was present as the only pathogen in 31% of the small bowel biopsies reviewed by light microscopy . Diarrhea due to Microsporidium sp . is frequently seen in advanced stages of AIDS with CD4 count cell below 200 mm3 Giemsa stain in the evaluation of small biopsies is a cheap and useful method to, identify Microsporidium sp.

J Tissue Viability, 1998 Jan, 8(1), 5 - 11
Observations on mattress covers: results of a pilot study; Thomas S; Samples of covers from three commercially available mattresses were examined in the laboratory using test methods originally devised for testing surgical dressings . These revealed that although the covers shared many common features, there were differences in the conformability and tensile properties which may be of some clinical relevance . The study also confirmed that with some minor modifications, the experimental techniques used would be suitable for a future, more comprehensive review of mattress performance . In a separate investigation designed to examine the consequences of a failure of a mattress cover, the bioburden of a foam core removed from a damaged cover revealed the presence of very large numbers of microorganism, well in excess of 10(10) per gram of foam which could act as a recevoir of contamination and thus a source of cross infection.

Invest Clin, 1999 Sep, 40(3), 165 - 77
{Ultrastructural identification of Ehrlichia sp in an experimentally infected dog in Venezuela}; Gutierrez N et al.; This study is the first report made in Venezuela concerning the ultrastructural characteristics of Ehrlichia sp in mononuclear blood cells from an experimentally infected dog . The animal developed clinical manifestations characteristic of the infection, and typical intracitoplasmic inclusion bodies were clearly seen in blood smears stained with modified Giemsa examined by light microscopy . Microorganisms were visualized by transmission electron microscopy . The cytoplasmic inclusions, consisted of membrane-lined vacuole-containing elementary bodies . The organisms were extremely pleomorphic . Elementary bodies were surrounded by two distinct membranes and each was constituted by electro-dense granules . These findings corresponded to the described electron microscopy morphology which characterizes the Ehrlichia genus.

Cell Signal, 1999 Sep, 11(9), 665 - 70
Dexamethasone differentially regulates cytokine transcription and translation in macrophages responding to bacteria or okadaic acid; Gewert K et al.; Many microorganisms and microbial products induce expression of pro-inflammatory cytokines such as interleukin-1 (IL-1alpha/beta) and tumour necrosis factor-alpha (TNF-alpha) in macrophages, primarily by transcriptional activation . We show here, by using mouse macrophages in primary culture, that pre-treatment with dexamethasone inhibits bacteria-induced IL-1beta expression as mRNA and cellular pro-IL-1beta in parallel, consistent with an effect primarily on transcriptional activation . In contrast, the expression of TNF-alpha mRNA was only partly inhibited despite virtually complete inhibition of TNF-alpha protein formation . Furthermore, the selective induction of primarily cell-associated 26,000 M, pro-TNF-alpha by the protein phosphatase inhibitor okadaic acid also was partly inhibited at the mRNA level by dexamethasone, whereas additional translational inhibition appeared to be lacking . This latter finding is reminiscent of earlier findings regarding signalling to activation of cytosolic phospholipase A2, which is sensitive to dexamethasone when elicited by bacteria, but not when elicited by okadaic acid . The present results raise the possibility that the inhibitory effect of dexamethasone on TNF-alpha translation, but not on transcriptional activation, is mediated by one or more okadaic acid-sensitive protein phosphatases.

Clin Infect Dis, 1999 Sep, 29(3), 522 - 5
Study on microbial persistence in end-stage idiopathic dilated cardiomyopathy; de Leeuw N et al.; Microbial persistence may be involved in the pathogenesis of idiopathic dilated cardiomyopathy (IDC) . Therefore, we evaluated the role of various cardiopathogenic microorganisms in patients with end-stage IDC . In a previous study, we did not find evidence for the persistence of enterovirus RNA in end-stage IDC . In the present study, we looked for other microorganisms that are frequently associated with heart disease, including cytomegalovirus, hepatitis B virus, hepatitis C virus, Borrelia burgdorferi, Chlamydia species, mycoplasmata, and Toxoplasma gondii . Serology, polymerase chain reaction (PCR) analysis specific for detection of microbial genomic sequences, or both investigations were performed on myocardial samples from 37 patients with end-stage IDC . PCR analysis was performed on multiple myocardial samples per patient . Thirty-nine patients with end-stage heart disease of known cause were included as controls . On the basis of our serological data and PCR analyses, we did not find any evidence that microbial persistence in the heart is involved in the end-stage disease process of IDC.

An Acad Bras Cienc, 1999, 71(3 Pt 2), 491 - 503
Evaluating the microbial diversity of soil samples: methodological innovations; Coutinho HL et al.; This manuscript is a review of the innovative methodologies that enable more precise evaluations of soil microbial diversity . Highlighting the molecular approach, which does not require the isolation of microorganisms and allows the inclusion of non-culturable genotypes in the analyses, the described methodologies revolutionised the environmental microbiology and opened gateways for an accurate understanding of the ecology and diversity of microorganisms . The application of techniques based on soil total DNA extraction, PCR amplification of genes or gene fragments, and sequence analysis revealed that the microbial universe is far more complex than ever imagined . Examples of applications of the molecular approach to study the diversity of soil diazotrophic bacteria are given.

Int Endod J, 1999 May, 32(3), 204 - 10
Black-pigmented anaerobic rods in closed periapical lesions; Bogen G et al.; AIM: This study determined the frequency of Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens in 20 closed periapical lesions associated with symptomatic and asymptomatic refractory endodontic disease . METHODOLOGY: To deliniate possible oral sources of P . endodontalis, the presence of the organism was assessed in selected subgingival sites and saliva in the same study patients . Periapical samples were obtained by paper points during surgical endodontic procedures using methods designed to minimize contamination by non-endodontic microorganisms . Subgingival plaque samples were obtained by paper points from three periodontal pockets and from the pocket of the tooth associated with the closed periapical lesion . Unstimulated saliva was collected from the surface of the soft palate . Bacterial identification was performed using a species-specific polymerase chain reaction (PCR) detection method . RESULTS: P . endodontalis was not identified in any periapical lesion, even though subgingival samples from eight patients (40%) revealed the P . endodontalis-specific amplicon . P . gingivalis occurred in one periapical lesion that was associated with moderate pain . P . nigrescens, P . endodontalis and P . intermedia were not detected in any periapical lesion studied . CONCLUSIONS: Black-pigmented anaerobic rods appear to be infrequent inhabitants of the closed periapical lesion.

Acta Biol Hung, 1998, 49(2-4), 421 - 7
Are the reductions in nematode attack on plants treated with seaweed extracts the result of stimulation of the formaldehyde cycle?
Jenkins T, Blunden G, Wu Y, Hankins SD, Gabrielsen BO.
Soil application to the roots of tomato plants (Lycopersicon esculentum) of a commercially-available alkaline extract of the brown alga, Ascophyllum nodosum, resulted in a significant reduction in the number of second-stage juveniles of both Meloidogynejavanica and M . incognita invading the roots, compared to those of plants treated with water alone . Egg recovery from the seaweed extract treated plants was also significantly lower . The three major betaines found in the seaweed extract (gamma-aminobutyric acid betaine, delta-aminovaleric acid betaine and glycinebetaine) also led to significant reductions in both the nematode invasion profile and egg recovery when applied at concentrations equivalent to those present in the extract . This led to the conclusion that the betaines present in the seaweed extract play a major role in bringing about the observed effects . Treatment of Arabidopsis thaliana plants with seaweed extract also resulted in a significant decrease in the number of females of M . javanica which developed in the roots . Significant reductions in egg recovery were also achieved from plants treated with the seaweed extract and similar effects were produced with the betaines found in the seaweed extract . As the experiments were conducted under monoxenic conditions, it can be concluded that the results obtained with the application of either the seaweed extract or betaines are not dependent on microorganisms associated with the rhizosphere.

Arch Microbiol, 1999 Oct, 172(4), 193 - 203
Physiology, phylogenetic relationships, and ecology of filamentous sulfate-reducing bacteria (genus desulfonema)
Fukui M, Teske A, Assmus B, Muyzer G, Widdel F.
Microscopy of organic-rich, sulfidic sediment samples of marine and freshwater origin revealed filamentous, multicellular microorganisms with gliding motility . Many of these neither contained sulfur droplets such as the Beggiatoa species nor exhibited the autofluorescence of the chlorophyll-containing cyanobacteria . A frequently observed morphological type of filamentous microorganism was enriched under anoxic conditions in the dark with isobutyrate plus sulfate . Two strains of filamentous, gliding sulfate-reducing bacteria, Tokyo 01 and Jade 02, were isolated in pure cultures . Both isolates oxidized acetate and other aliphatic acids . Enzyme assays indicated that the terminal oxidation occurs via the anaerobic C(1) pathway (carbon monoxide dehydrogenase pathway) . The 16S rRNA genes of the new isolates and of the two formerly described filamentous species of sulfate-reducing bacteria, Desulfonema limicola and Desulfonema magnum, were analyzed . All four strains were closely related to each other and affiliated with the delta-subclass of Proteobacteria . Another close relative was the unicellular Desulfococcus multivorans . Based on phylogenetic relationships and physiological properties, Strains Tokyo 01 and Jade 02 are assigned to a new species, Desulfonema ishimotoi . A new, fluorescently labeled oligonucleotide probe targeted against 16S rRNA was designed so that that it hybridized specifically with whole cells of Desulfonema species . Filamentous bacteria that hybridized with the same probe were detected in sediment samples and in association with the filamentous sulfur-oxidizing bacterium Thioploca in its natural habitat . We conclude that Desulfonema species constitute an ecologically significant fraction of the sulfate-reducing bacteria in organic-rich sediments and microbial mats.

Clin Infect Dis, 1999 Nov, 29(5), 1287 - 94
Skin hygiene and infection prevention: more of the same or different approaches?
Larson E.
The purpose of this article is to review research indicating a link between hand hygiene and nosocomial infections and the effects of hand care practices on skin integrity and to make recommendations for potential changes in clinical practice and for further research regarding hand hygiene practices . Despite some methodological flaws and data gaps, evidence for a causal relationship between hand hygiene and reduced transmission of infections is convincing, but frequent handwashing causes skin damage, with resultant changes in microbial flora, increased skin shedding, and risk of transmission of microorganisms, suggesting that some traditional hand hygiene practices warrant reexamination . Some recommended changes in practice include use of waterless alcohol-based products rather than detergent-based antiseptics, modifications in lengthy surgical scrub protocols, and incorporation of moisturizers into skin care regimens of health care professionals.

Arthritis Rheum, 1999 Oct, 42(10), 2198 - 203
Detection of bacterial DNA in serial synovial samples obtained during antibiotic treatment from patients with septic arthritis; van der Heijden IM et al.; OBJECTIVE: The management of septic arthritis could benefit from sensitive tests that detect the persistence of microorganisms in the joint . The aim of this study was to determine the feasibility of monitoring the presence of bacterial DNA in synovial samples from septic arthritis patients during antibiotic treatment . METHODS: Synovial fluid (SF) and synovial tissue (ST) samples were collected serially from 6 patients with septic arthritis before and during antibiotic therapy . In addition, peripheral blood (PB) samples were available for polymerase chain reaction (PCR) analysis from 5 of the 6 patients before treatment . All samples were analyzed for the presence of bacterial DNA with the use of a PCR with universal 16S ribosomal RNA primers . Automated sequencing and comparative data analysis were performed to identify the species . These data were compared with Gram staining and culture results . RESULTS: The bacterial species cultured from the synovium could be identified in all 6 patients using PCR and subsequent sequence analysis of the amplicons . In virtually all cases, positive Gram stain and culture findings in the synovial samples became negative after 2-3 days of antibiotic treatment . Bacterial DNA persisted in the SF and/or ST after culture conversion; in 2 patients, bacterial DNA was still detected at day 10, in 1 patient, at day 20, and in another patient, at day 22 after the initiation of treatment . Synovial samples were available for PCR analysis from 2 patients at day 26 . At this time point, bacterial DNA could not be detected anymore . All PB samples were negative by both culture and PCR analysis . CONCLUSION: PCR analysis can be used to monitor the presence of bacterial DNA in synovial samples from patients with septic arthritis during antibiotic treatment . The absence of bacterial DNA could help in the decision to discontinue antibiotic treatment.

Ugeskr Laeger, 1999 Sep 13, 161(37), 5161 - 4
{Infections and cardiovascular disease}; Kolmos HJ et al.; Epidemiological studies indicate that respiratory tract and dental infections increase the risk of atherosclerotic cardiovascular disease . Several microorganisms have been claimed as clinically important, especially Chlamydia pneumoniae (Cp) and cytomegalovirus (CMV), Cp is frequently isolated from atherosclerotic plaques, and treatment with macrolide antibiotics may have a beneficial effect on the course of ischaemic heart disease . CMV seems to play a role in the development of coronary stenosis following coronary bypass surgery and heart transplantation . Likewise, inflammatory markers are associated with atherosclerotic cardiovascular disease . The pathogenetic role of microorganisms may be ascribed to the inflammatory response, which is elicited during infection . There is an urgent need for more documentation of the role of microorganisms in cardiovascular disease, and of the possible clinical effect of antibiotic treatment.

Oncol Rep, 1999 Nov-Dec, 6(6), 1257 - 9
A radioimmunoassay for the measurement of paclitaxel and taxanes in biological specimens using commercially available reagents; Guillemard V et al.; We have developed a rapid and sensitive radioimmunoassay for the measurement of paclitaxel and related taxanes in biological specimens using commercially available reagents . The presence of paclitaxel competitively inhibited the binding of radioactive paclitaxel to polyclonal anti-taxane antibody or anti-taxane monoclonal antibody . When using polyclonal antibody, this method detected paclitaxel in concentrations as low as 0.87 nM and was also effective in 20% methanol . This radioimmunoassay is useful for the measurement of paclitaxel and taxanes in biological specimens like culture medium of paclitaxel-producing microorganisms and may be useful for the measurement of paclitaxel and related compounds in other potential natural sources.

J Clin Microbiol, 1999 Nov, 37(11), 3761 - 3
Recovery of mycobacteria from patients with cystic fibrosis; Bange FC et al.; Despite decontamination, overgrowth by pseudomonads renders cultural isolation of mycobacteria from respiratory specimens of patients with cystic fibrosis (CF) difficult or impossible . We performed a prospective study by comparing levels of reduction of overgrowth and recovery of mycobacteria using either pretreatment with N-acetyl-L-cysteine (NALC)-NaOH alone or pretreatment with NALC-NaOH and then with oxalic acid . From 406 specimens of 148 CF patients, 11 specimens were positive for mycobacteria, 5 of which grew mycobacteria after decontamination by either procedure . Three specimens grew mycobacteria only after decontamination with NALC-NaOH, whereas three specimens grew mycobacteria only after treatment with NALC-NaOH followed by oxalic acid but were overgrown after decontamination with NALC-NaOH . Thus, inactivation of mycobacteria by the more aggressive oxalic acid treatment offsets its beneficial effect of reducing the proportion of cultures overgrown with microorganisms other than mycobacteria.

Oral Dis, 1999 Apr, 5(2), 144 - 9
Noma (cancrum oris): questions and answers; Enwonwu CO et al.; Noma (cancrum oris) is an infectious disease which destroys the oro-facial tissues and other neighboring structures in its fulminating course . It affects predominantly children aged 2-16 years in sub-Saharan Africa where the estimated frequency in some communities may vary from one to seven cases per 1000 children . The key risk factors are poverty, malnutrition, poor oral hygiene, deplorable environmental sanitation, close residential proximity to livestock, and infectious diseases, particularly measles . Malnutrition acts synergistically with endemic infections in promoting an immunodeficient state, and noma results from the interaction of general and local factors with a weakened immune system as the common denominator . Acute necrotizing gingivitis (ANG) is considered the antecedent lesion . Current studies suggest that evolution of ANG to noma requires infection by a consortium of microorganisms with Fusobacterium necrophorum and Prevotella intermedia as the suspected key players . Without appropriate treatment, mortality rate is 70-90% . Survivors suffer the two-fold affliction of oro-facial disfigurement and functional impairment . Reconstructive surgery of the resulting deformity is time-consuming and financially prohibitive for the victims who are poor.

Am J Obstet Gynecol, 1999 Oct, 181(4), 989 - 94
A role for the novel cytokine RANTES in pregnancy and parturition; Athayde N et al.; OBJECTIVE: RANTES (regulated on activation, normal T cell expressed and secreted), a potent and versatile chemokine, is capable of attracting monocytes, lymphocytes, basophils, and eosinophils . This cytokine has been implicated in the regulation of the inflammatory response and in the recruitment of macrophages to the implantation site in early pregnancy . RANTES messenger ribonucleic acid and protein have been detected in fetal tissue and first-trimester trophoblast in response to bacterial endotoxin . The purpose of this study was to determine whether intrauterine infection, parturition (preterm and term), and gestational age affect the amniotic fluid concentrations of RANTES in human pregnancy . STUDY DESIGN: A cross-sectional study was designed to examine the relationship between labor, microbial invasion of the amniotic cavity, gestational age, and RANTES expression in amniotic fluid . Amniotic fluid was obtained from 214 women in the following groups: (1) midtrimester (n = 22), (2) preterm labor with intact membranes in the presence (n = 20) or absence (n = 74) of microbial invasion of the amniotic cavity, (3) term, not in labor (n = 44) and term, in labor in the presence (n = 27) and absence (n = 27) of microbial invasion of the amniotic cavity . Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture for microorganisms . RANTES concentrations were determined by use of a sensitive and specific immunoassay . RESULTS: (1) Amniotic fluid RANTES concentrations decrease with advancing gestational age (r = 0 . 43; P <.01) . (2) Labor at term was associated with an increase in median concentrations of RANTES (labor-median, 8.4 pg/mL; range, <1.3-94.4 vs no labor-median, <1.3 pg/mL; range, <1.3-230.3; P <.01) . (3) Women with preterm labor who delivered preterm (no microbial invasion of the amniotic cavity) had a higher median concentration of amniotic fluid RANTES than those who delivered at term (median, 12.7 pg/mL; range, <1.3-928 vs median, <1.3 pg/mL; range, <1.3-127 . 5; P <.001) . (4) Microbial invasion of the amniotic cavity was associated with a significant increase in median amniotic fluid RANTES in both preterm and term labor (preterm labor with microbial invasion of the amniotic cavity-median, 51.6 pg/mL; range, <1.3-2290 vs preterm labor without microbial invasion of the amniotic cavity-median, 12.7 pg/mL; range, <1.3-928 and vs preterm labor with delivery at term-median, <1.3 pg/mL; range, <1.3-127.5; P <.001 for each; term labor with microbial invasion of the amniotic cavity-median, 16.8 pg/mL; range, <1.3-171.4 vs term labor without microbial invasion of the amniotic cavity-median, 8.4 pg/mL; range, <1.3-94.4; P <.05 and vs no labor and no microbial invasion of the amniotic cavity-median, 1.4 pg/mL; range, <1.3-230.3; P <.001 and P <.05, respectively) . CONCLUSION: These results support a role for RANTES in the mechanisms of human parturition and in the regulation of the host response to intrauterine infection.

Science, 1999 Oct 15, 286(5439), 525 - 8
Beta-defensins: linking innate and adaptive immunity through dendritic and T cell CCR6; Yang D et al.; Defensins contribute to host defense by disrupting the cytoplasmic membrane of microorganisms . This report shows that human beta-defensins are also chemotactic for immature dendritic cells and memory T cells . Human beta-defensin was selectively chemotactic for cells stably transfected to express human CCR6, a chemokine receptor preferentially expressed by immature dendritic cells and memory T cells . The beta-defensin-induced chemotaxis was sensitive to pertussis toxin and inhibited by antibodies to CCR6 . The binding of iodinated LARC, the chemokine ligand for CCR6, to CCR6-transfected cells was competitively displaced by beta-defensin . Thus, beta-defensins may promote adaptive immune responses by recruiting dendritic and T cells to the site of microbial invasion through interaction with CCR6.

J Microbiol Methods, 1999 Oct, 38(1-2), 69 - 80
An immunochemical in situ approach to detect adaptation processes in the photosynthetic apparatus of diatoms of the Wadden Sea sediment surface layers; Hust M et al.; Intertidal Wadden Sea sediment surface layers located near the North Sea shore at Dangast (Germany) were subjected to quantitative chlorophyll and protein extractions followed by SDS-PAGE and Western immunoblotting . During the study, benthic diatoms were almost exclusively the only group of microphytobenthos in this area performing oxygenic photosynthesis . Three successive extractions with 90% acetone yielded more than 98% of the extractable pigments . The absorption spectra of the extracts of sediment samples were nearly identical to those obtained from the diatom Phaeodactylum tricornutum . Ten repetitive extractions with SDS containing loading buffer used for SDS-PAGE ensured that more than 98% of the extractable protein was recovered . Subsequent Western immunoblotting with an antiserum directed against the subunits of the main light harvesting complex of the diatom Cyclotella cryptica showed that the antiserum immunodecorated selectively subunits of diatomaceous light harvesting complexes . This finding demonstrated that a taxon specific class of polypeptides could be visualized and quantified directly in sediment samples . In shading experiments, shaded sedimient areas generally revealed higher amounts of light harvesting subunits which could be immunodecorized . The improved mnethodological approach and the results are discussed in the context of the current development of direct molecular methods for the investigation of activities and adaptation processes of specific groups of microorganisms in their natural habitats.

J Microbiol Methods, 1999 Oct, 38(1-2), 43 - 52
Combination of biomolecular and stable isotope techniques to determine the origin of organic matter used by bacterial communities: application to sediment; Creach V et al.; Natural isotopic composition is a good tool to trace organic matter in ecosystems . Recent studies used a combination of molecular and stable isotope techniques to determine the origin of the organic carbon used by bacteria in the water column . In our study, we show that this procedure can be used for analysis of sediment bacterial communities with few modifications . In the water column, bacterial recovery is done before DNA extraction . In the sediment, we tested qualitatively and quantitatively a direct and indirect extraction of DNA . The direct extraction was the most efficient . It recovered between 3.1 and 15.8 microg DNA g(-1) dry sediment and the contamination of field samples by eucaryotic DNA was less than 13% . In this preliminary study of the salt marsh ecosystem, the delta(13)C values of DNA (-26 to - 24%) recovered from the sediment were close to the delta(13)C values of halophytic plants (-26.4 and - 25.3%) showing a relationship between plants and microorganisms . Thus, this procedure can be used to trace the flow of carbon through the sediment microbial biomass and to understand the variation of bacterial activity according to the inputs of allocthonous and autochtonous organic matter.

Proc Assoc Am Physicians, 1999 Sep-Oct, 111(5), 383 - 9
Myeloperoxidase; Klebanoff SJ; Phagocytes respond to stimulation with a burst of oxygen consumption, and much, if not all, of the extra oxygen consumed in the respiratory burst is converted first to the superoxide anion and then to hydrogen peroxide (H2O2) . Myeloperoxidase (MPO), which is released from cytoplasmic granules of neutrophils and monocytes by a degranulation process, reacts with the H2O2 formed by the respiratory burst to form a complex that can oxidize a large variety of substances . Among the latter is chloride, which is oxidized initially to hypochlorous acid, with the subsequent formation of chlorine and chloramines . These products of the MPO-H2O2-chloride system are powerful oxidants that can have profound biological effects . The primary function of neutrophils is the phagocytosis and destruction of microorganisms, and the release of MPO and H2O2 into the phagosome containing the ingested microorganism generally leads to a rapid microbicidal effect . Neutrophils from patients with chronic granulomatous disease (CGD) have a microbicidal defect that is associated with the absence of a respiratory burst and, thus, H2O2 production . Neutrophils from patients with a hereditary MPO deficiency, who lack MPO, also have a microbicidal defect, although it is not as severe as that seen in CGD . MPO and H2O2 also can be released to the outside of the cell where a reaction with chloride can induce damage to adjacent tissue and, thus, contribute to the pathogenesis of disease . It has been suggested that pulmonary injury, renal glomerular damage, and the initiation of atherosclerotic lesions may be caused by the MPO system.

Eur J Biochem, 1999 Nov, 265(3), 896 - 901
Cloning, sequencing and heterologous expression of pyrogallol-phloroglucinol transhydroxylase from Pelobacter acidigallici; Baas D et al.; A genomic lambda-library of Pelobacter acidigallici has been established . Proteolytic digestion of homogeneous pyrogallol-phloroglucinol transhydroxylase from the same microorganism afforded polypeptide fragments whose N-terminal sequences allowed the generation of oligonucleotide primers . Together with primers deduced from the known N-terminal sequences of the two intact subunits these were used in PCR experiments to obtain three amplificates . Screening the lambda-library with the three amplificates led eventually to clones containing the whole gene coding for the transhydroxylase . Sequencing the gene revealed two open reading frames coding for 875 and 275 amino acids which correspond to the alpha- and beta-subunits of THL, respectively . The two subunits are separated by a 48-bp noncoding region . Comparison of the sequence with those of other molybdopterin cofactor (MoCo)-enzymes places THL in the dimethylsulfoxide reductase family . Possible contact sites to the MoCo and to the iron-sulphur clusters were spotted . Using the expression vectors pQE 30 and pT 7-7 three constructs harbouring the THL gene were created . One of them carried a His6-tag at the N-terminus of the alpha-subunit, another at the C-terminus of the beta-subunit . Immunoblot analysis showed high expression of THL, but the inclusion bodies could not be refolded to active enzyme.

Nucleic Acids Res, 1999 Nov 1, 27(21), 4218 - 22
Whole genome-based phylogenetic analysis of free-living microorganisms; Fitz-Gibbon ST et al.; A phylogenetic 'tree of life' has been constructed based on the observed presence and absence of families of protein-encoding genes observed in 11 complete genomes of free-living microorganisms . Past attempts to reconstruct the evolutionary relation-ships of microorganisms have been limited to sets of genes rather than complete genomes . Despite apparent rampant lateral gene transfer among microorganisms, these results indicate a single robust underlying evolutionary history for these organisms . Broadly, the tree produced is very similar to the small subunit rRNA tree although several additional phylogenetic relationships appear to be resolved, including the relationship of Archaeoglobus to the methanogens studied . This result is in contrast to notions that a robust phylogenetic reconstruction of microorganisms is impossible due to their genomes being composed of an incomprehensible amalgam of genes with complicated histories and suggests that this style of genome-wide phylogenetic analysis could become an important method for studying the ancient diversification of life on Earth . Analyses using informational and operational subsets of the genes showed that this 'tree of life' is not dependent on the phylogenetically more consistent informational genes.

Proc Natl Acad Sci U S A, 1999 Oct 12, 96(21), 11758 - 63
Cytidine 5'-triphosphate-dependent biosynthesis of isoprenoids: YgbP protein of Escherichia coli catalyzes the formation of 4-diphosphocytidyl-2-C-methylerythritol; Rohdich F et al.; 2-C-methylerythritol 4-phosphate has been established recently as an intermediate of the deoxyxylulose phosphate pathway used for biosynthesis of terpenoids in plants and in many microorganisms . We show that an enzyme isolated from cell extract of Escherichia coli converts 2-C-methylerythritol 4-phosphate into 4-diphosphocytidyl-2-C-methylerythritol by reaction with CTP . The enzyme is specified by the hitherto unannotated ORF ygbP of E . coli . The cognate protein was obtained in pure form from a recombinant hyperexpression strain of E . coli harboring a plasmid with the ygbP gene under the control of a T5 promoter and lac operator . By using the recombinant enzyme, 4-diphosphocytidyl-{2-(14)C}2-C-methylerythritol was prepared from {2-(14)C}2-C-methylerythritol 4-phosphate . The radiolabeled 4-diphosphocytidyl-2-C-methylerythritol was shown to be efficiently incorporated into carotenoids by isolated chromoplasts of Capsicum annuum . The E . coli ygbP gene appears to be part of a small operon also comprising the unannotated ygbB gene . Genes with similarity to ygbP and ygbB are present in the genomes of many microorganisms, and their occurrence appears to be correlated with that of the deoxyxylulose pathway of terpenoid biosynthesis . Moreover, several microorganisms have genes specifying putative fusion proteins with ygbP and ygbB domains, suggesting that both the YgbP protein and the YgbB protein are involved in the deoxyxylulose pathway . A gene from Arabidopsis thaliana with similarity to ygbP carries a putative plastid import sequence, which is well in line with the assumed localization of the deoxyxylulose pathway in the plastid compartment of plants.

Ann Occup Hyg, 1999 Aug, 43(6), 393 - 404
Field testing of a personal size-selective bioaerosol sampler; Kenny LC et al.; Existing samplers for the collection of bioaerosols have been designed with the aim of maintaining biological stability of the collected material, and in general do not select particles in accordance with international conventions for aerosol sampling . Many have uncharacterised sampling efficiencies and few are designed as personal samplers . If standard personal dust samplers are used for bioaerosols the viability of collected microorganisms may be compromised by dehydration . The objective of this study was to evaluate a novel personal bioaerosol sampler designed to collect the inhalable dust fraction and further subdivide the sample into thoracic and respirable fractions . The new sampler was tested to see whether it enhanced the survival of the collected microorganisms, and was assessed for ease of use in the field and in subsequent laboratory analyses . A number of occupation-related field sites were selected where large concentrations of bioaerosols were to be expected . The prototype sampler was found to be simple to use . Analysis could be carried out with similar efficiency either with all three fractions together for a total count, or separately for size selective data . The sampler performed at least as well as the standard IOM filter method but with the added advantage of size fractionation . The field trials showed that for sampling periods lasting several hours, microorganism survival within the sampler was adequate for culture and identification of the organisms present . This new sampler is now commercially available . In addition to bioaerosol sampling, the principle of size selective sampling using porous foams can be applied to other occupational hygiene problems, and also to indoor air monitoring of PM10 and PM2.5 concentrations.

Crit Rev Food Sci Nutr, 1999 Sep, 39(5), 391 - 440
Radiation processing to improve the quality of fishery products; Venugopal V et al.; Extensive investigations, worldwide, in the last 4 decades have shown the benefits of radiation processing for the preservation and microbial quality improvement of seafoods . In the present review, the various factors determining the quality of seafoods are first presented . The basic principles underlying the effects of ionizing radiation and specific effects on food constituents such as proteins, amino acids, lipids, vitamins, and tissue enzymes are discussed . Data on radiation processing of seafoods are reported and discussed with respect to shelf life enhancement under refrigeration by control of bacteria causing spoilage, radiation sensitivity of pathogenic microorganisms and parasites of public health significance and their elimination in fresh and frozen fishery products, control of insect disinfestation in dried fishery products, influence of irradiation on nutritional and sensory quality attributes, detection of irradiation treatment, economics, and international status.

Free Radic Biol Med, 1999 Oct, 27(7-8), 797 - 809
Role of distinct subpopulations of peritoneal macrophages in the regulation of reactive oxygen species release; Fernandez ML et al.; It has been reported in vitro that during the respiratory burst of phagocytic cells the superoxide anion production per cell shows a negative relation with the cell density . This process has been described as autoregulation . The aim of this work was to analyze the superoxide anion production in thioglycollate-elicited peritoneal macrophage exudates to evaluate the importance of the peritoneal cavity environment in the autoregulation process . 12-O-tetradecanoylphorbol-13-acetate (PMA) was used to stimulate the respiratory burst and superoxide anion production was measured evaluating the intracellular formazan deposits that precipitate as a result of nitro blue tetrazolium (NBT) reduction . We have demonstrated a negative correlation between superoxide anion production and cell density in the peritoneal cavity in macrophages challenged with PMA . The response of individual cells was analyzed by means of an image analyzer, measuring the amount of formazan per cell and cell-size changes during the process of activation . The results revealed that the decrease in individual cell response as a function of higher cell densities were due to a significant increase in the amount of basal reaction macrophages . Concomitantly, the number of reactive cells remained unchanged irrespective of the cell density of the population . A direct correlation between cell size and superoxide anion production was observed . This phenomenon was demonstrated in SENCAR and Balb/c strains . However, macrophages from SENCAR mice showed greater superoxide anion production than those from Balb/c.The differences between strains could be associated to the increased sensitivity to PMA tumor promotion of SENCAR mice . Based on this property, macrophages from SENCAR mice were stimulated with opsonized zymosan, a particulate stimulus that reflects the interaction macrophage-microorganism during the phagocytic process . This data will contribute to the knowledge of infection control . We conclude that variations in basal reaction cells modulates the macrophage activation response when excess macrophages are recruited to the peritoneum . This is demonstrated using different stimuli, thus suggesting that this response may be applied to a wide variety of stimuli-macrophage interactions . The differences between strains may be associated to the increased sensitivity to PMA tumor promotion of SENCAR mice.

Alcohol Clin Exp Res, 1999 Sep, 23(9), 1528 - 33
Nitric oxide-dependent ethanol stimulation of ciliary motility is linked to cAMP-dependent protein kinase (PKA) activation in bovine bronchial epithelium; Sisson JH et al.; BACKGROUND: The first line of protection in the lung from the outside environment is provided by the mucociliary apparatus, which continually clears the airways of inhaled microorganisms, dust, and debris . Because alcohol is known to impair airway host defenses, we have examined the effects of ethanol on mucociliary function . In earlier studies, we found that ethanol rapidly and transiently stimulates ciliary motility through a nitric oxide-dependent mechanism . Because many agonists stimulate ciliary motility through activation of cyclic nucleotide-dependent protein kinases, we hypothesized that ethanol stimulates ciliary motility by activating protein kinases . METHODS: Protein kinase activity and ciliary beat frequency (CBF) were assayed in primary cultures of bovine bronchial epithelial cells after exposure to ethanol . RESULTS: Ethanol markedly activated cyclic adenosine monophosphate (cAMP)-dependent protein kinase {protein kinase A (PKA)} at biologically relevant concentrations (20-100 mM), with activation detectable after 15 min and persisting up to 4 hr . Ethanol's PKA activation was blocked by nitric oxide synthase inhibitors, indicating a nitric oxide-dependent pathway, and was also specifically blocked by PKA inhibitors . Ethanol did not directly activate cyclic guanosine monophosphate (cGMP)-dependent protein kinase {protein kinase G (PKG)} in bovine bronchial epithelial cells, but inhibitors of PKG attenuated PKA activation, suggesting a link between PKA activation and PKG activation during ethanol exposure . CBF increased in parallel to PKA activation, suggesting tight coupling between stimulated CBF and PKA activation . CONCLUSION: We conclude that ethanol stimulates CBF through activating PKA in bovine bronchial epithelial cells and we suggest a cooperative mechanism involving PKA and nitric oxide.

Am J Infect Control, 1999 Oct, 27(5), 377 - 84
Compliance with recommended infection control procedures among Canadian dentists: results of a national survey; McCarthy GM et al.; OBJECTIVES: The objective of this study was to investigate compliance with recommended infection control (IC) practices by dentists in Canada in 1995 . DESIGN: A mailed survey of a stratified random sample of dentists (N = 6444), with 3 follow-up attempts . Weighted analyses included multiple logistic regression to identify the best predictors of "excellent" compliance (18 items) . RESULTS: The adjusted response rate was 66.4% . Respondents reported use of an IC manual (52%); postexposure protocol (41%); biologic monitoring of heat-sterilizers (71%); hepatitis B immunization of dentists (91%: of these 72% had post-immunization screening; natural immunity 3%) all hygienists (78%), and all other clinical staff (70%); handwashing (before treating patients 76%, after degloving 63%); always wearing gloves (95%); changing gloves after each patient (97%); masks (82%); protective eyewear (82%); protective uniform (48%); puncture-proof container for sharps (94%); recapping needles with scoop technique/device (60%); flushing waterlines (55%); heat-sterilizing handpieces (94%; after each patient 77%); high-volume suction (92%) and "excellent" compliance (6%) . Significant predictors of "excellent compliance" included attending continuing education about IC (>/=10 hours, odds ratio {OR} = 6.3; 6-10 hours, OR = 3.3), treating 20 to 29 patients per day (OR = 2.8), being women (OR = 2.7), and population of city in which practice is located (>500,000, OR = 2.5) . CONCLUSION: Improvements in IC are necessary in dental practice . The introduction of mandatory continuing education about IC may improve compliance with recommended IC procedures, which is important because of concerns related to transmission of bloodborne pathogens and drug-resistant microorganisms.

J Antimicrob Chemother, 1999 Sep, 44(3), 403 - 6
In-vitro activity of polycationic peptides against Cryptosporidium parvum, Pneumocystis carinii and yeast clinical isolates; Giacometti A et al.; The in-vitro activity of magainin II, indolicidin and ranalexin against 14 clinical isolates of eukaryotic microorganisms was evaluated . Antifungal susceptibility testing was performed by broth microdilution, and activity against Pneumocystis carinii and Cryptosporidium parvum was determined by inoculation on to cell monolayers . For yeasts, peptide MICs and MFCs ranged from 6.25 to > 50 mg/L . Ranalexin showed the highest activity against Candida spp., while magainin II demonstrated greatest anticryptococcal activity . The peptides suppressed the growth of P . carinii by > or = 50% and > or = 90% at 5 and 50 microM, respectively, with the exception of indolicidin . Ranalexin, the most effective compound against C . parvum, suppressed its growth by > or = 40% at 50 microM.

Arch Biochem Biophys, 1999 Oct 15, 370(2), 240 - 9
Sodium chloride-induced volume changes of freshwater cyanobacterium Synechococcus sp . PCC 7942 cells can be probed by chlorophyll a fluorescence; Stamatakis K et al.; Freshwater species of the cyanobacterial genus Synechococcus import NaCl passively, and export Na(+) actively, by means of primary and secondary extrusion mechanisms . As a result of the ion and water fluxes, cell volumes are enlarged . We show in this paper that the NaCl-induced volume enlargement of Synechococcus sp . PCC 7942 cells is attended by a rapid (k = 0.39 s(-1)) increase in chlorophyll (Chl) a fluorescence . The cell turgor threshold (measured by osmotic titration of Chl a fluorescence) was lower in the absence of NaCl (0.195 Osm kg(-1)) than in the presence of 0.4 M NaCl (0.248 Osm kg(-1)) indicating NaCl uptake by the cells . Turgor thresholds of cells suspended in NaCl-containing medium were enlarged further by protonophoric uncouplers, P-type ATPase inhibitors, and light starvation, conditions that are known to interfere with the active extrusion of Na(+) ions . Cell swelling exerts probably a regulation on the distribution of phycobilisome (PBS) excitation between photosystem II (fluorescent Chl a) and photosystem I (nonfluorescent Chl a), since it affects PBS-sensitized Chl a fluorescence, but not directly excited Chl a fluorescence . The dependence of the Chl a fluorescence of cyanobacteria on cell volumes allows probing of bioenergetic phenomena that are related to dynamic osmotic volume changes, transmembrane solute and water fluxes, plasma membrane permeabilities, and internal osmotic conditions of cyanobacterial cells . Thus, cyanobacteria may serve as quite convenient models of aquatic microorganisms in experimental studies directed toward the elucidation of perception mechanisms and defense mechanisms of water and solute stresses .

J Clin Gastroenterol, 1999 Oct, 29(3), 266 - 9
Pathologic features of the gastric mucosa adjacent to primary MALT-lymphomas; Herrera-Goepfert R et al.; The frequency of reported cases of primary gastric mucosa-associated lymphoid tissue (MALT)-lymphoma is increasing worldwide . Helicobacter pylori plays a preponderant role in its pathogenesis . Gastric MALT-lymphoma arises from nonrecirculating centrocytelike cells located at the periphery of reactive lymphoid follicles, which are common in patients infected with this microorganism . Histopathologic features other than lymphoid follicles have not been well described . In this study the authors describe the morphologic changes in the gastric mucosa adjacent to MALT-lymphomas . From the files of the departments of pathology at the Instituto Nacional de Cancerologia and the Instituto Nacional de la Nutricion in Mexico City, primary gastric MALT-lymphomas were retrieved . Patients with hematoxylin-eosin-stained histologic sections, including the overt neoplasia and the neighboring gastric mucosa, were selected . Lymphoid follicles as well as intestinal metaplasia, atrophy, and eosinophils were evaluated as present or absent and graded as proposed by the Updated Sydney System for gastritis . Fifty-one patients were eligible for analysis . There were 35 low-grade and 16 high-grade primary MALT-lymphomas . Forty-seven patients (92.6%) showed reactive lymphoid follicles in the neighboring mucosa, 32 patients (69.5%) had intestinal metaplasia, and 26 patients (54.1%) demonstrated atrophy . In 41 patients (73.8%) there was an increased number of eosinophils . Our findings suggest that lymphoid follicles, intestinal metaplasia, atrophy, and eosinophils in an endoscopic biopsy are markers of both gastric lymphoma and carcinoma.

Curr Opin Biotechnol, 1999 Oct, 10(5), 485 - 91
Novel approaches in food-processing technology: new technologies for preserving foods and modifying function; Knorr D; Recent advances in emerging food-processing technologies, such as high hydrostatic pressure or high-intensity electric field pulses, allow targeted and sophisticated modification and preservation of foods . We are beginning to understand the mechanisms involved in pressure inactivation of bacterial spores and have been collecting considerable amounts of kinetic data regarding inactivation mechanisms of enzymes and vegetative microorganisms . We are also gaining more insight into the permeabilization of plant membranes and related biosynthetic responses, making progress in food structure engineering and food modification for function, and have been initiating process developments for gentle processing of delicate biomaterials based on pressure-assisted phase transitions of water.

Curr Opin Biotechnol, 1999 Oct, 10(5), 411 - 21
Recombinant protein expression in Escherichia coli; Baneyx F; Escherichia coli is one of the most widely used hosts for the production of heterologous proteins and its genetics are far better characterized than those of any other microorganism . Recent progress in the fundamental understanding of transcription, translation, and protein folding in E . coli, together with serendipitous discoveries and the availability of improved genetic tools are making this bacterium more valuable than ever for the expression of complex eukaryotic proteins.

Angew Chem Int Ed Engl, 1999 Sep, 38(18), 2763 - 2766
The Concept of Docking/Protecting Groups in Biohydroxylation; Braunegg G et al.; A general principle for biohydroxylation, in which time-consuming screening and enrichment techniques are avoided, is demonstrated by the introduction of a docking/protecting group into the substrate . This facilitates acceptance by the microorganism and allows the use of a narrow range of microorganisms, for example Beauveria bassiana ATTC 7159 (B . b.), for the hydroxylation of compounds with diverse structures . After the biohydroxylation, the docking/protecting group is removed (see scheme).

Int Immunol, 1999 Oct, 11(10), 1693 - 700
Multivalent cross-linking of membrane Ig sensitizes murine B cells to a broader spectrum of CpG-containing oligodeoxynucleotide motifs, including their methylated counterparts, for stimulation of proliferation and Ig secretion; Goeckeritz BE et al.; We have previously reported that B cells that are activated by multivalent but not bivalent membrane Ig cross-linking ligands synergize with various B cell activators culminating in enhanced B cell proliferation . In this study we asked whether B cells that are activated by a multivalent mIg cross-linking agonist could respond to oligodeoxynucleotides (ODN) containing non-stimulatory motifs . Earlier reports have shown that ODN containing a CpG motif in which the cytosine is unmethylated and is flanked by two 5' purines and two 3' pyrimidines induce high levels of B cell activation, while ODN whose CpG are methylated or flanked by sequences other than the optimal two 5' purines and two 3' pyrimidines were non-stimulatory . In this manuscript we show that when B cells are stimulated in vitro with dextran-conjugated anti-IgD antibodies (anti-IgD-dex), as the multivalent mIg ligand, their proliferation is enhanced and they can be induced to secrete Ig in response to ODN containing various non-optimal motifs, both methylated and non-methylated . Furthermore we could induce synergistic levels of proliferation with concentrations of anti-IgD-dex that were in the picomolar concentration range and with concentrations of ODN that were 10- to 100-fold less than previously reported to be necessary for mitogenic activity . These data provided a model to explain how low concentrations of a multi-epitope-expressing microorganism in the context of mammalian (methylated) or microorganism (non-methylated) DNA can lead to dysregulated B cell proliferation and Ig secretion.

Appl Environ Microbiol, 1999 Oct, 65(10), 4464 - 9
Effects of combined shear and thermal forces on destruction of Microbacterium lacticum; Bulut S et al.; A twin-screw extruder and a rotational rheometer were used to generate shear forces in concentrated gelatin inoculated with a heat-resistant isolate of a vegetative bacterial species, Microbacterium lacticum . Shear forces in the extruder were mainly controlled by varying the water feed rate . The water content of the extrudates changed between 19 and 45% (wet weight basis) . Higher shear forces generated at low water contents and the calculated die wall shear stress correlated strongly with bacterial destruction . No surviving microorganisms could be detected at the highest wall shear stress of 409 kPa, giving log reduction of 5.3 (minimum detection level, 2 x 10(4) CFU/sample) . The mean residence time of the microorganism in the extruder was 49 to 58 s, and the maximum temperature measured in the end of the die was 73 degrees C . The D(75 degrees C) of the microorganism in gelatin at 65% water content was 20 min . It is concluded that the physical forces generated in the reverse screw element and the extruder die rather than heat played a major part in cell destruction . In a rotational rheometer, after shearing of a mix of microorganisms with gelatin at 65% (wt/wt) moisture content for 4 min at a shear stress of 2.8 kPa and a temperature of 75 degrees C, the number of surviving microorganisms in the sheared sample was 5.2 x 10(6) CFU/g of sample compared with 1.4 x 10(8) CFU/g of sample in the nonsheared control . The relative effectiveness of physical forces in the killing of bacteria and destruction of starch granules is discussed.

Vet Immunol Immunopathol, 1999 Sep 20, 70(3-4), 309 - 16
Serum levels of chicken mannan-binding lectin (MBL) during virus infections; indication that chicken MBL is an acute phase reactant; Nielsen OL et al.; Mannan-binding lectin (MBL) is a serum collectin which is believed to be an opsonin of the innate immune defence against various microorganisms . MBL is a minor acute phase reactant in man . We investigated the concentration of serum MBL in chickens infected with infectious bronchitis virus (IBV) and infectious laryngotracheitis virus (ILTV) . The concentration of serum MBL increased about twofold (from approximately 6 to 12 microg/ml) due to these viral infections . The concentration peaked 3-7 days after infection with IBV, and 3-5 days after ILTV infection, depending on the ILTV strain used . The increased levels returned to normal values 6-10 days after infection . The results indicated that MBL is a minor acute phase reactant in chickens.

Biotechnol Bioeng, 1999 Nov 20, 65(4), 474 - 9
Model of dissolved organic carbon distribution for substrate-sufficient continuous culture; Liu Y; The growth yields (Yobs) are greater under substrate-limited conditions than those under substrate-sufficient conditions in continuous cultures . This indicates that the excess substrate should cause uncoupling between anabolism and catabolism . It appears that the excess substrate could determine metabolic pathways of microorganisms, which further control dissolved organic carbon (DOC) distribution under substrate-sufficient conditions . However, how to quantitatively describe the DOC distribution remains unclear in substrate-sufficient continuous culture . Based on a balanced DOC reaction, a DOC distribution model was developed in relation to residual substrate concentration for substrate-sufficient continuous cultures . Results showed that a considerable portion of the DOC consumed was directly oxidized to carbon dioxide through energy spilling under substrate-sufficient conditions . The proposed model for the first time quantified the DOC distribution between nongrowth-associated and growth-associated metabolisms of cells . The proposed model was verified with literature data very well .

J Bone Joint Surg Am, 1999 Sep, 81(9), 1261 - 7
Anterior instrumentation for the treatment of spinal tuberculosis; Yilmaz C et al.; BACKGROUND: Kyphosis and neurological impairment are the major residual problems of spinal tuberculosis after the microorganism has been eradicated with use of appropriate medications . Spinal instrumentation is needed to support anterior strut grafts in patients who have kyphosis that affects more than two levels . Most surgeons use posterior instrumentation . Anterior instrumentation, despite its advantages, has not been widely accepted, partly because of concerns about introducing foreign material into infected tissue . The purpose of the current study was to address those concerns . METHODS: Twenty-two patients who had tuberculosis of the spine with moderate-to-severe localized kyphosis and sixteen patients who had more than two involved levels had stabilization with anterior instrumentation . Antituberculous medication was used postoperatively according to a standardized regimen . The patients were followed to determine if there was any recurrence of the disease and if the correction had been maintained . RESULTS: The twenty-two patients who had involvement of one or two levels had an average correction of the deformity of 64 percent (range, 58 to 90 percent), and the sixteen patients who had more than two levels of involvement had an average correction of 81 percent (range, 75 to 97 percent) . The correction was maintained in twenty-one patients, the maximum loss was 3 degrees in sixteen, and one patient died on the second postoperative day . There was no recurrence of the disease . CONCLUSIONS: We believe that anterior instrumentation is more effective than posterior instrumentation for reducing the deformity and stabilizing the vertebral column in patients who have kyphosis related to tuberculosis of the spine.

Environ Health Perspect, 1999 Oct, 107 Suppl 5, 753 - 65
Metals and kidney autoimmunity; Bigazzi PE; The causes of autoimmune responses leading to human kidney pathology remain unknown . However, environmental agents such as microorganisms and/or xenobiotics are good candidates for that role . Metals, either present in the environment or administered for therapeutic reasons, are prototypical xenobiotics that cause decreases or enhancements of immune responses . In particular, exposure to gold and mercury may result in autoimmune responses to various self-antigens as well as autoimmune disease of the kidney and other tissues . Gold compounds, currently used in the treatment of patients with progressive polyarticular rheumatoid arthritis, can cause a nephrotic syndrome . Similarly, an immune-mediated membranous nephropathy frequently occurred when drugs containing mercury were commonly used . Recent epidemiologic studies have shown that occupational exposure to mercury does not usually result in autoimmunity . However, mercury induces antinuclear antibodies, sclerodermalike disease, lichen planus, or membranous nephropathy in some individuals . Laboratory investigations have confirmed that the administration of gold or mercury to experimental animals leads to autoimmune disease quite similar to that observed in human subjects exposed to these metals . In addition, studies of inbred mice and rats have revealed that a few strains are susceptible to the autoimmune effects of gold and mercury, whereas the majority of inbred strains are resistant . These findings have emphasized the importance of genetic (immunogenetic and pharmacogenetic) factors in the induction of metal-associated autoimmunity . (italic)In vitro(/italic) and (italic)in vivo(/italic) research of autoimmune disease caused by mercury and gold has already yielded valuable information and answered a number of important questions . At the same time it has raised new issues about possible immunostimulatory or immunosuppressive mechanisms of xenobiotic activity . Thus it is evident that investigations of metal-induced renal autoimmunity have the potential to produce new knowledge with relevance to autoimmune disease caused by xenobiotics in general as well as to idiopathic autoimmunity.

Biosci Biotechnol Biochem, 1999 Aug, 63(8), 1475 - 7
Arg-gingipain inhibition and anti-bacterial activity selective for Porphyromonas gingivalis by malabaricone C; Shinohara C et al.; Effects of malabaricon C, isolated from nutmeg (Myristica fragrans), on Arg-gingipain activity and growth of several kinds of anaerobic and aerobic microorganisms were investigated . Malabaricone C irreversibly inhibited Arg-gingipain by 50% at a concentration of 0.7 microgram/ml and selectively suppressed Porphyromomas gingivalis growth.

Biosci Biotechnol Biochem, 1999 Aug, 63(8), 1467 - 70
Effects of glucose on lipase activity; Tsuzuki W et al.; To establish the utility of lipase as a biocatalyst, the effects of glucose on the hydrolysis activities of lipase were investigated . Among 13 kinds of lipase from microorganisms, 6 lipases were inhibited in hydrolysis up to 50% of the original activities by 10 mM glucose . The activities of other microbial lipases and 2 kind of porcine pancreatic lipases were not affected by the addition of glucose . Six lipases that were sensitive to glucose were modified by a synthetic detergent . After they were converted to modified lipases, they were not inhibited by glucose . Even at 20 mM glucose, each modified lipase retained more than 95% activity compared with that in the absence of glucose . In the modified lipase, the detergent attached to the lipase molecule would disturb the access of glucose to the enzyme . To detect the interaction between lipase and glucose, the fluorescence of tryptophan was traced . The fluorescence intensities of lipases that were inhibited by glucose depended on the concentration of glucose, suggesting that glucose induced some structural change in the lipase molecule.

Adv Microb Physiol, 1999, 41, 139 - 227
The histidine protein kinase superfamily; Grebe TW et al.; Signal transduction in microorganisms and plants is often mediated by His-Asp phosphorelay systems . Two conserved families of proteins are centrally involved: histidine protein kinases and phospho-aspartyl response regulators . The kinases generally function in association with sensory elements that regulate their activities in response to environmental signals . A sequence analysis with 348 histidine kinase domains reveals that this family consists of distinct subgroups . A comparative sequence analysis with 298 available receiver domain sequences of cognate response regulators demonstrates a significant correlation between kinase and regulator subfamilies . These findings suggest that different subclasses of His-Asp phosphorelay systems have evolved independently of one another.

Scand J Gastroenterol Suppl, 1999, 230, 9 - 16
24-h recording of intragastric pH: technical aspects and clinical relevance; van Herwaarden MA et al.; BACKGROUND: Information about gastric acid secretion and gastric acidity can be obtained using several techniques but, presently, continuous intragastric pH recording is probably the one applied most frequently . This paper aims to review the technical aspects and some important applications of intragastric pH monitoring in research and clinical practice . METHODS: Literature review . RESULTS: Most studies on intragastric pH are performed with either glass or antimony electrodes . Optimal measurement of 24-h intragastric pH requires accurate calibration of the pH measuring system, exact positioning of the pH electrodes, and a sufficient sample rate . Depending on the aim of the study the results of intragastric pH monitoring are expressed either as median H+ activity or as median pH values . Gastric acidity shows a circadian rhythm, modified by buffering meals and nocturnal duodenogastric reflux . In health, age, gender and smoking habits are known to influence gastric acidity . In duodenal ulcer disease an increased gastric acidity is found and in patients with gastric ulcer gastric acidity is decreased . In GERD, no relation between reflux oesophagitis and gastric acidity is found . Helicobacter pylori affects intragastric pH most pronounced during acid inhibitory therapy, both in DU patients and in healthy subjects . In the absence of H . pylori the effect of proton-pump inhibitors on intragastric pH is much less than in the presence of the microorganism, whereas the effect of ranitidine on intragastric pH is barely affected by the H . pylori status . CONCLUSIONS: Despite some limitations, intragastric pH monitoring provides important information about gastric acidity.

J Biol Inorg Chem, 1999 Apr, 4(2), 162 - 5
Ab initio structure solution of a dimeric cytochrome c3 from Desulfovibrio gigas containing disulfide bridges; Frazao C et al.; The 1.2 A resolution crystal structure of the 29 kDa di-tetrahaem cytochrome c3 from the sulfate reducing bacterium Desulfovibrio gigas was solved by ab initio methods, making this the largest molecule to be solved by this procedure . The actual refined model of the cysteine-linked dimeric molecule reveals that this molecule is very similar to the non-covalently linked symmetrical dimer of the di-tetrahaem cytochrome c3 from Desulfomicrobium norvegicum . Each monomer has the typical polypeptide fold, haem arrangement and iron coordination found for the tetrahaem cytochrome c3 molecules . The interface between the covalently linked monomers in the asymmetric unit of the crystal shows a pseudo two-fold arrangement, disturbed from symmetry by crystal packing forces . The fact that D . gigas contains a dimeric tetrahaem cytochrome with solvent accessible disulfide bridges and that this cytochrome specifically couples hydrogen oxidation to thiosulfate reduction in bacterial extracts provides an interesting aspect related to disulfide exchange reactions in this microorganism.

Biochemistry (Mosc), 1999 Aug, 64(8), 952 - 6
Degradation of maltose by proliferating cells of Desulfovibrio desulfuricans 2198; Zolotukhina LM et al.; Desulfovibrio desulfuricans 2198 can grow on maltose-based medium only in the presence of yeast extract . The results of kinetic measurements of maltose consumption by the cells show that there is no marked difference in Km and Vmax values for this bacterium versus other carbohydrate-utilizing microorganisms . The determination of some enzymes of sugar metabolism in D . desulfuricans 2198 suggests that maltose degradation occurs by the Embden--Meyerhof pathway . The cell extract also contains glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase . 2-Keto-3-deoxy-6-phosphogluconate aldolase, the key enzyme of the Entner--Doudoroff pathway, is not found in D . desulfuricans 2198 . In the bacterium grown on {U-14C}maltose-containing medium, a portion of the labeled carbon is incorporated into biomass . As degradation products, labeled acetate and carbon dioxide are found.

Med Mycol, 1999 Jun, 37(3), 159 - 62
Prevalence of Malassezia spp . in the ears of asymptomatic cattle and cattle with otitis in Brazil; Duarte EP et al.; Yeasts of the genus Malassezia are lipophilic microorganisms that are saprophytes that can act as opportunistic pathogens in animals . Malassezia pachydermatis is commonly isolated from the ear canal and skin of healthy dogs, or in association with seborrheic dermatitis and otitis externa conditions . The objective of the present study was to determine the occurrence of Malassezia spp . in the ears of healthy bovines and bovines with otitis . Specimens (secretion or cerumen) were collected with sterile swabs, inoculated onto Mycosel medium, supplemented with olive oil, and incubated at 35 degrees C for 1 week . Yeasts were identified according to morphological characteristics, growth in Dixon medium at 32 degrees C and Sabouraud glucose medium modified by the addition of Tween 20, 40 or 80 . The results showed that 54.7% of the cultures were positive in bovines with otitis (75) and 34.6% were positive in healthy bovines (378) . Analysis of the positive cultures (41) from animals with otitis allowed presumptive identification of 24 strains corresponding to M . globosa (12), M . slooffiae (5), M . furfur (5) and M . sympodialis (2) . Further studies on a larger number of animals may confirm the trend verified thus far, i.e . a higher frequency of isolation of Malassezia spp . from animals with otitis than from healthy animals (P<0.01) and a predominance of the species M . globosa.

Am J Trop Med Hyg, 1999 Sep, 61(3), 495 - 9
Antibodies to sulfatide in leprosy and leprosy reactions; Spierings E et al.; Antibodies to sulfatide have been reported in various demyelinating peripheral polyneuropathies . We have investigated the diagnostic value of these antibodies in leprosy . Anti-sulfatide IgM in leprosy patients was not significantly elevated . High anti-sulfatide IgG titers were observed in individuals from endemic areas, irrespective of their leprosy status, while western European controls were negative . No significant correlation was found between IgM or IgG antibody titers and leprosy classification, although multibacillary patients had higher anti-sulfatide IgM titers than paucibacillary patients . In addition, 23 patients developing leprosy reactions were followed longitudinally . Antibody titers in these patients fluctuated slightly during the follow-up period . There was no association with the occurrence of leprosy reactions or treatment . Thus, IgG titers against sulfatides are high in both leprosy patients and healthy controls in endemic areas, whereas such antibodies are not found in western European controls, suggesting that these antibodies are induced by environmental factors, such as microorganisms.

Can J Microbiol, 1999 Jul, 45(7), 541 - 54
Organotin compounds and their interactions with microorganisms; White JS et al.; Organotin compounds are ubiquitous in the environment . The general order of toxicity to microorganisms increases with the number and chain length of organic groups bonded to the tin atom . Tetraorganotins and inorganic tin have little toxicity . Because of their lipophilicity, organotins are regarded as membrane active . There is evidence that the site of action of organotins may be both at the cytoplasmic membrane and intracellular level . Consequently, it is not known whether cell surface adsorption or accumulation within the cell, or both is a prerequisite for toxicity . Biosorption studies on a fungus, cyanobacteria, and microalgae indicates that cell surface binding alone occurred in these organisms, while studies on the effects of TBT (tributyltin) on certain microbial enzymes indicated that in some bacteria TBT can interact with cytosolic enzymes . Microorganism-organotin interactions are influenced by environmental conditions . In aquatic systems, both pH and salinity can determine organotin speciation and therefore reactivity . These environmental factors may also alter selectivity for resistant microorganisms in polluted systems . Tin-resistant microorganisms have been identified, and resistance can be either plasmid or chromosomally mediated . In one TBT-resistant organism, an Altermonas sp., an efflux system was suggested as the resistance mechanism . Biotransformation of organotin compounds by debutylation or methylation has been observed . These reactions may influence the toxicity, mobility, and environmental fate of organotin compounds.

J Biol Chem, 1999 Oct 1, 274(40), 28436 - 44
Phagosomal maturation, acidification, and inhibition of bacterial growth in nonphagocytic cells transfected with FcgammaRIIA receptors; Downey GP et al.; Phagocytosis and killing of microbial pathogens by professional phagocytes is an essential component of the innate immune response . Recently, heterologous transfection of individual receptors into nonmyeloid cells has been used successfully to elucidate the early steps that signal phagosome formation . It is unclear, however, whether the vacuoles formed by such transfected cells are bona fide phagosomes, capable of fusion with endomembranes, of luminal acidification, and of controlling the growth of microorganisms . The aim of the current study was to determine whether COS-1 and Chinese hamster ovary cells, rendered phagocytic by expression of human FcgammaRIIA receptors, express the cellular machinery required to support phagosomal maturation . Immunolocalization studies demonstrated that early endosomes, as well as late endosomes and/or lysosomes, fuse sequentially with phagosomes in the transfectants . Microfluorescence ratio imaging of particles labeled with pH-sensitive dyes revealed that maturation of the phagosome was accompanied by luminal acidification . The drop in pH, which attained levels comparable to those reported in professional phagocytes, was prevented by inhibitors of vacuolar-type H(+)-ATPases . Optimal phagosomal acidification required elevation of cytosolic {Ca(2+)}, suggesting that it results from fusion of endomembranes bearing proton pumps . Moreover, the transfected cells effectively internalized live bacteria . Opsonization was essential for bacterial internalization, implying that it occurred by FcgammaRIIA-mediated phagocytosis, as opposed to invasion . Uptake into phagolysosomes was associated with inhibition of bacterial growth, due at least in part to the low intraphagosomal pH . These studies indicate that the biochemical events that follow receptor-mediated particle internalization in cells transfected with FcgammaRIIA receptors closely resemble the process of phagosomal maturation in neutrophils and macrophages . FcgammaRIIA-transfected cells can, therefore, be used as a model for the study of additional aspects of phagocyte biology.

Infect Immun, 1999 Oct, 67(10), 5441 - 6
Significance of host cell kinesin in the development of Chlamydia psittaci; Escalante-Ochoa C et al.; The influence of the microtubule-associated motor protein kinesin on Chlamydia psittaci inclusion development in epithelial and fibroblast cell lines was addressed . Kinesin was blocked early after chlamydial internalization (4 h postinfection {p.i.}) and before the initiation of active chlamydial multiplication (8 h p.i.) . Chlamydia development was monitored by fluorescence and transmission electron microscopy at different times during the cycle . In both host cell lines, kinesin blockage restricted mitochondria from the chlamydial vacuole . The effects of kinesin blockage on the C . psittaci replication cycle included the presence of multiple inclusions up to late in the cycle, the presence of enlarged pleomorphic reticulate bodies, and a delayed reappearance of elementary bodies . The last effect seems to be greater when kinesin is blocked early after infection . Our results show that kinesin activity is required for optimal development of these microorganisms, most probably acting through the apposition of mitochondria to the C . psittaci inclusions.

Neurology, 1999 Sep 22, 53(5), 1104 - 6
Interferon-gamma-inducing factor (IL-18) and interferon-gamma in inflammatory CNS diseases; Fassbender K et al.; OBJECTIVE: To examine the intrathecal production of a newly identified cytokine, interferon-gamma-inducing factor (IL-18), together with interferon-gamma itself, in inflammatory diseases of the CNS (i.e., bacterial meningitis, viral meningoencephalitis, and MS) . RESULTS: IL-18 concentrations in CSF were significantly increased in bacterial meningitis and tended toward increased levels in viral meningoencephalitis . In contrast, IL-18 was detectable only in a few patients with MS and healthy controls . Interestingly, interferon-gamma was significantly increased selectively in CSF of patients with viral meningoencephalitis . CONCLUSION: The observation of an intrathecal release of IL-18 in patients with meningitis argues for a pathophysiologic role of this novel cytokine in immunity against invading microorganisms the CNS.

Tsitologiia, 1999, 41(7), 605 - 9
{Features of consequences of osmotic modification at different steps of cell heating}; Morozov II et al.; The influence of media with different osmotic pressure (NaCl water solutions) on survival and permeability of Escherichia coli B/r and Escherichia coli Bs-1 cells heated up to 50, 52 and 60 degrees C was investigated . Hypotonic media increased, while hypertonic media, within a certain range of sodium chloride concentrations, decreased the damaging action of heating independently of the temperature . The effectiveness of thermoprotection was seen to increase, and the range of osmolyte concentrations, at which the highest effect of protection takes place, to move markedly towards higher concentrations of NaCl with increase in heating temperature . A certain relationship is suggested between the observed phenomenon and the osmotic homeostasis system of microorganisms under condition of thermogenic and tonic stress.

Prikl Biokhim Mikrobiol, 1999 May-Jun, 35(3), 275 - 81
{Quasichemical models of dynamics of cell populations after treatment with growth inhibitors and activators}; Ershov IuA; A uniform procedure is proposed, whereby growth characteristics of biological populations of various levels can be described as quantum chemistry equations . Using approaches of the kinetics of chain processes expressions have been derived, which make it possible to assess the effects of individual chemical substances and mixtures thereof on population dynamics . These expressions describe quantitatively synergistic and antagonistic effects of the substances . The models proposed describe the kinetics of growth of various populations (such as cultures of microorganisms) and can serve as a basis for targeted regulation of biotechnological processes.

Tohoku J Exp Med, 1999 May, 188(1), 89 - 94
Decrease in multiple sclerosis with acute transverse myelitis in Japan; Nakashima I et al.; Acute transverse myelitis (ATM) may be a manifestation of multiple sclerosis (MS) and was reported to be more common among Japanese MS patients than in Caucasian MS patients . Recently there are arguments whether clinical manifestations of MS may have changed . Therefore, we studied the frequency of ATM in MS and the clinical subtypes of MS in 86 clinically definite MS patients whose onsets were in 1970-1979, 1980-1989, and 1990-1998 in Sendai City, Japan . Fifty-six of the patients were women and 30 were men . Forty-four patients had the conventional form of MS (C-MS) commonly seen in Western countries, and 42 had optic-spinal or spinal forms of MS (OSS-MS) . Twenty MS patients had ATM, and all of them were belong to optic-spinal form of MS . ATM was not seen in any cases of C-MS . The mean onset age (years) of the clinical subtypes was 25.5 in C-MS, 34.1 in OSS-MS without ATM, and 30.9 in OSS-MS with ATM . Among the patients whose onset of the disease was in 1970-1979, 60.0% of them were cases of OSS-MS with ATM, but such cases were markedly decreased to 5.3% in 1990-1998 . In contrast, the frequency of C-MS increased to 63.2% in 1990-1998 compared with 20.0% in 1970-1979 . Analysis of the data by the year of birth of the patients showed similar results . Our data suggest that the frequency of ATM in MS markedly decreased, and that of C-MS increased during the last 30 years in Sendai, Japan . Since the genetic background of Japanese has not changed, some exogenous factors, such as food, infectious microorganisms, and chemicals in our environment, may be responsible for the change.

Biol Chem, 1999 Jul-Aug, 380(7-8), 909 - 14
Some of the early events underlying Th2 cell maturation and susceptibility to Leishmania major infection in BALB/c mice; Himmelrich H et al.; The first experimental evidence for the development of polarized CD4+ Th1 and Th2 responses in vivo has been obtained using the murine model of infection with Leishmania major, an intracellular parasite of macrophages in their vertebrate host . Genetically determined resistance and susceptibility to infection with this parasite have been clearly demonstrated to result from the development of polarized Th1 and Th2 responses, respectively . Using this model system, the dominant role of cytokines in the induction of polarized CD4+ responses has been validated in vivo . The requisite role of IL-4 in mediating both Th2 differentiation and susceptibility to infection in BALB/c mice has directed interest towards the search for evidence of IL-4 production early after infection and identification of its cellular source . We have been able to demonstrate a burst of IL-4 production in susceptible BALB/c mice within the first day of infection with L . major and could establish that this rapidly produced IL-4 instructed Th2 lineage commitment of subsequently activated CD4+ T cells and stabilized this commitment by downregulating IL-12 Rbeta2 chain expression, resulting in susceptibility to infection . Strikingly, this early IL-4 response to infection resulted from the cognate recognition of a single epitope in a distinctive antigen, LACK, from this complex microorganism by a restricted population of CD4+ T cells that express Vbeta4-Valpha8 T cell receptors.

Br J Biomed Sci, 1999, 56(1), 56 - 65
Deoxyribonucleic acid typing methods for medically important microorganisms; Williams DW et al.; The ability to type microorganisms to a sub-species level plays an essential role in the diagnosis, treatment and control of human infection . Traditionally, differentiation of microorganisms has involved analysis of phenotypic markers . However, these methods are not universally applicable to all microorganisms, and results may be influenced by environmental factors . Recent developments in DNA analysis, together with the limitations of phenotypic methods, have resulted in an increasing use of procedures based on DNA analysis for the typing of clinically important microorganisms . The aim of this review is to provide an overview of the advantages and disadvantages of the genetic typing techniques currently available.

Trans R Soc Trop Med Hyg, 1999 May-Jun, 93(3), 261 - 3
Seroconversion for Helicobacter pylori in adults from Brazil; de Oliveira AM et al.; We studied, prospectively, seroconversion for Helicobacter pylori in adults from a developing country and investigated risk factors for the acquisition of the microorganism in this population . A group of 213 volunteers of low socioeconomic level from a district in the metropolitan area of Belo Horizonte, south-east Brazil was evaluated . Anti-H . pylori IgG antibodies were measured by ELISA using Cobas Core anti-H . pylori EIA (Roche) in serum samples collected in 1992 and in 1997 . The subjects were interviewed and sociodemographic data were collected . A total of 174 (81.7%) subjects presented anti-H . pylori antibodies on the occasion of the first visit . During 56 months of follow-up, 2 of 39 seronegative adults converted to seropositive with an annual infection rate of 1.1%, and 2 of 174 seropositive subjects reverted to seronegative (0.2%/year) . The prevalence of infection increased significantly with age and an inverse association was observed between prevalence of infection and educational level . In conclusion, the results of the present study demonstrate that in a developing country there is a low but continuous risk of H . pylori infection in adulthood.

J Am Dent Assoc, 1999 Sep, 130(9), 1354 - 9
Assessing the clinical effectiveness of an aerosol reduction device for the air polisher; Muzzin KB et al.; BACKGROUND: Because of the growing concern of the infectious nature of aerosols produced by air polishers, the Centers for Disease Control and Prevention and the American Dental Association have made recommendations to minimize dental aerosols . In addition, a device was developed in 1997 to reduce the aerosol generated during air polishing . METHODS: The authors conducted a blinded clinical study to determine the effectiveness of an aerosol reduction device during air polishing . All 30 subjects underwent two minutes of air polishing, one with the aerosol reduction device on one side of the mouth and one without the device on the opposite side . Microbial samples were collected on blood agar plates positioned 12 inches from the subject's mouth and from one plate attached to the dental hygienist's face mask . The sample plates were then inverted and incubated for three days at 37 C . RESULTS: Using the paired t-test, the authors found that the air polisher without the aerosol reduction device generated a significantly greater mean quantity of colony-forming units, or CFUs, 12 inches from the subject's mouth (mean +/- standard deviation, 148.00 +/- 145.00 CFUs) than the air polisher with the aerosol reduction device (20.10 +/- 53.90 CFUs) (P < .0001) . In addition, the air polisher without the aerosol reduction device generated a significantly greater number of CFUs on the face mask plate (40.90 +/- 33.80 CFUs) than the air polisher with the aerosol reduction device (8.80 +/- 15.10 CFUs) (P < .0001) . CONCLUSION: The data suggest that the aerosol reduction device is effective in reducing the number of microorganisms generated during air polishing . CLINICAL IMPLICATIONS: Air polishing with the aerosol reduction device may decrease the potential for disease transmission.

J Food Prot, 1999 Sep, 62(9), 1088 - 96
Pulsed electric field processing of foods: a review; Jeyamkondan S et al.; Use of pulsed electric fields (PEFs) for inactivation of microorganisms is one of the more promising nonthermal processing methods . Inactivation of microorganisms exposed to high-voltage PEFs is related to the electromechanical instability of the cell membrane . Electric field strength and treatment time are the two most important factors involved in PEF processing . Encouraging results are reported at the laboratory level, but scaling up to the industrial level escalates the cost of the command charging power supply and of the high-speed electrical switch . In this paper, we critically review the results of earlier experimental studies on PEFs and we suggest the future work that is required in this field . Inactivation tests in viscous foods and in liquid food containing particulates must be conducted . A successful continuous PEF processing system for industrial applications has yet to be designed . The high initial cost of setting up the PEF processing system is the major obstacle confronting those who would encourage the system's industrial application . Innovative developments in high-voltage pulse technology will reduce the cost of pulse generation and will make PEF processing competitive with thermal-processing methods.

J Food Prot, 1999 Sep, 62(9), 1059 - 70
Giardia, Cryptosporidium, and Cyclospora and their impact on foods: a review; Rose JB et al.; While the risk from pathogenic microorganisms in foods has been recognized for hundreds of years, bacterial agents are generally implicated as the contaminants . Although many outbreaks of gastroenteritis caused by protozoan pathogens have occurred, it is only in the last 3 years that attention has focused on protozoan association with foodborne transmission . Recognized as waterborne parasites, Giardia, Cryptosporidium, and Cyclospora have now been associated with several foodborne outbreaks . The oocysts and cysts of these organisms can persist and survive for long periods of time both in water and on foods . While Cyclospora oocysts require a maturation period, Cryptosporidium oocysts and Giardia cysts are immediately infectious upon excretion from the previous host . As a result, these parasites have emerged as public health risks and have become a concern to the food industry . More than 200 cases of foodborne giardiasis (seven outbreaks) were reported from 1979 to 1990 . Four foodborne Cryptosporidium outbreaks (with a total of 252 cases) have been documented since 1993 . Cyclospora caused a series of sporadic outbreaks of cyclosporasis throughout North America that have affected over 3,038 people since 1995 . Control and prevention of protozoan foodborne disease depends upon our ability to prevent, remove, or kill protozoan contaminants . This review will address the biology, foodborne and waterborne transmission, survival, and methods for detection and control of Giardia, Cryptosporidium, and Cyclospora.

Science, 1999 Sep 17, 285(5435), 1889 - 92
Iron isotope biosignatures; Beard BL et al.; The (56)Fe/(54)Fe of Fe-bearing phases precipitated in sedimentary environments varies by 2.5 per mil (delta(56)Fe values of +0.9 to -1 . 6 per mil) . In contrast, the (56)Fe/(54)Fe of Fe-bearing phases in igneous rocks from Earth and the moon does not vary measurably (delta(56)Fe = 0.0 +/- 0.3 per mil) . Experiments with dissimilatory Fe-reducing bacteria of the genus Shewanella algae grown on a ferrihydrite substrate indicate that the delta(56)Fe of ferrous Fe in solution is isotopically lighter than the ferrihydrite substrate by 1.3 per mil . Therefore, the range in delta(56)Fe values of sedimentary rocks may reflect biogenic fractionation, and the isotopic composition of Fe may be used to trace the distribution of microorganisms in modern and ancient Earth.

Int J Food Microbiol, 1999 Sep 15, 50(1-2), 151 - 3
Physiology of food spoilage organisms; Roller S; A thorough understanding of the physiological responses of microorganisms to stresses imposed during food preservation is essential if novel combination systems based on mild food processing procedures are to be developed effectively . The influences of intrinsic characteristics as well as external factors such as water activity, temperature, preservatives, composition of the gaseous atmosphere, etc . on the stress response of microorganisms are discussed . The interaction of spoilage organisms with each other as well as with food pathogens and the ultimate consequences for food safety and quality are also explored in this review.

Int J Food Microbiol, 1999 Sep 15, 50(1-2), 119 - 30
Methodology for detection and typing of foodborne microorganisms; de Boer E et al.; Over the past decade many improvements have been seen in both conventional and modern methods for the detection of pathogenic bacteria in foods . Modifications and automation of conventional methods in food microbiology include sample preparation, plating techniques, counting and identification test kits . ATP bioluminescence techniques are increasingly used for measuring the efficiency of cleaning surfaces and utensils . Cell counting methods, including flow cytometry and the direct epifluorescent filter technique are suitable techniques for rapid detection of microorganisms, especially in fluids . Automated systems based on impedimetry are able to screen high numbers of samples based on total bacterial counts within 1 day . Immunoassays in a wide range of formats make rapid detection of many pathogens possible . Recently, there have been important developments in the use of nucleic acid-based assays for the detection and subtyping of foodborne pathogens . The sensitivity of these methods has been significantly increased by the use of the polymerase chain reaction and other amplification techniques . Alternative and rapid methods must meet several requirements concerning accuracy, validation, speed, automation, sample matrix, etc . Both conventional and rapid methods are used within hazard analysis critical control point programs . Further improvements especially in immunoassays and genetic methods can be expected, including the use of biosensors and DNA chip technologyPublication Types:

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