Bacteria

Arch Virol, 1995, 140(6), 1007 - 14
LTR-directed homologous recombination of full-length HIV-1 provirus clone in recA(-) bacteria; Yamada K et al.; During molecular cloning of full-length retroviral plasmid clones occurrence of homologous recombination (HR) between LTR regions is frequently observed . In order to evaluate appropriate host bacterial strains for cloning such HR-prone plasmids, we utilized a linearized template plasmid containing a full-length HIV-1 proviral sequence . The plasmid was linearized within the viral sequence so that plasmid transformed bacteria would grow only when the plasmid was circularized by HR . Using this genetic system for detecting HR, we evaluated the frequency of HR in various recA(-) bacterial strains which are commercially available and in some recA-null strains in which recA-defective phenotype was constructed by P1 transduction . We found that HR occurred even in recA-null strains although in lesser frequencies . The nucleotide sequence analysis at the junction of recombination revealed no loss, insertion or duplication of DNA sequence . It is suggested that recombination machinery other than the RecA system is involved.

J Anim Sci, 1995 Jan, 73(1), 257 - 66
Fractionation of nitrogen isotopes by mixed ruminal bacteria; Wattiaux MA et al.; Mixed ruminal bacteria were cultured with glucose, cellulose or no carbohydrate, and ammonium bicarbonate or casein hydrolysate . Changes in amounts of bacterial ammonia and non-ammonia N were measured . Ratios of N isotopes expressed as delta 15N (delta 15N) were measured by isotope ratio mass spectrometry . When bacteria were cultured with glucose and ammonium bicarbonate, bacterial delta 15N decreased from .9 to -5.8/1000 and residual ammonia delta 15N increased from -1.4 to 12.7/1000 . Fractionation of N isotope occurred during ammonia incorporation because the difference between delta 15N of ammonia and delta 15N of bacteria (delta 15N) was 18.8/1000 (P < .01) . However, when casein hydrolysate was the N source, delta 15N between non-ammonia and bacteria averaged only 1.3/1000 (P > .1), indicating no fractionation of N isotopes occurred during utilization of amino acids . The amount of bacterial N was highest at 24 h of incubation when cellulose was the carbohydrate source . At that time, delta 15N between ammonia and bacteria was 8.9/1000 when ammonia was the N source, but delta 15N between non-ammonia and bacteria was 1.7/1000 when casein hydrolysate was the N source . Bacterial N decreased after 24 h when cellulose was the source of carbohydrate . Results indicate that fractionation of N isotopes occurred during ammonia incorporation, but not during incorporation of N from amino acids, deamination, and release of ammonia . Fractionation of N isotopes during incorporation of ammonia N may be used as a marker to study N metabolism by ruminal bacteria.

Sci Prog, 1995, 78 ( Pt 1), 19 - 34
Biological activities of lipopolysaccharides from oral bacteria and their relevance to the pathogenesis of chronic periodontitis; Wilson M; Chronic periodontitis is a major cause of tooth loss in adults and is a consequence of the colonisation of the subgingival region by organisms such as Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum . Lipopolysaccharide (LPS) is a constituent of the cell walls of all of these bacteria and is found in large quantities on the surfaces of periodontally-diseased teeth . LPS from oral bacteria has a marked effect on most types of cell found in the periodontal tissues including macrophages, lymphocytes, fibroblasts and osteoblasts . Fibroblasts and macrophages respond to oral LPS by secreting a range of cytokines, and other effector molecules, with inflammatory, immunomodulatory and tissue-destroying capabilities . Lymphocytes are stimulated by LPS to produce a wide range of antibodies with different specificities, hence exacerbating the inflammatory response . By its actions on bone cells, LPS can stimulate bone resorption and inhibit bone formation resulting in erosion of the tooth-supporting alveolar bone . There is, therefore, considerable evidence implicating LPS in the pathogenesis of chronic periodontitis . However, the possible involvement of other biologically-active bacterial components must not be overlooked.

Arch Surg, 1994 Dec, 129(12), 1338 - 42
Treatment of burned mice with hyperbaric oxygen reduces mesenteric bacteria but not pulmonary neutrophil deposition; Tenenhaus M et al.; OBJECTIVE: Hyperbaric oxygen (HBO) is used but unproven for many conditions, including burns . We hypothesized that HBO therapy might increase oxygen delivery to intestine during burn shock and decrease mucosal injury . SETTING: University research laboratory . DESIGN AND STUDY PARTICIPANTS: We studied the effects of HBO therapy (100% oxygen at 2.4 atm absolute) on mesenteric bacterial colonies (MBCs) in mice following 32% total body surface area burns . MBCs were counted 24 or 48 hours postburn by culturing mesenteric tissue . Intestinal histologic features were examined, acid-base balance was measured, and pulmonary neutrophil deposition was estimated by lung myeloperoxidase content . INTERVENTIONS: HBO delivered in a compression chamber . MAIN OUTCOME MEASURE: Numbers of mice with MBCs . RESULTS: With twice-daily HBO treatments, each treatment lasting 1.5 or 2 hours, fewer burned mice had MBCs . Three HBO treatments within 24 hours produced seizures, death, and increased numbers of mice with MBCs . Numbers of mice with MBCs were not influenced when compressed air (2.4 atm absolute) or 100% oxygen (1 atm absolute) was used . Villus histologic findings showed less damage in burned mice that received HBO therapy than in controls . Metabolic acidosis was not affected by HBO therapy, nor were lung myeloperoxidase levels . CONCLUSION: HBO therapy was associated with reduced numbers of mice with MBCs after burn injury and reduced histologic evidence of mucosal damage, but lung myeloperoxidase levels and metabolic acidosis were not affected . HBO therapy may increase oxygen delivery to ischemic intestine and improve cellular metabolism; alternatively, increased tissue oxygen may augment killing of translocated bacteria by phagocytic cells . HBO deserves further investigation for burn treatment, but because of the narrow therapeutic window and continued neutrophil sequestration in the lungs, we should proceed cautiously.

J Am Coll Surg, 1994 Dec, 179(6), 679 - 88
Effect of secretory IgA on transepithelial passage of bacteria across the intact ileum in vitro; Albanese CT et al.; BACKGROUND: Bacterial translocation is a process believed to result in nosocomial infections . Secretory IgA (sIgA) may have a role in the prevention of translocation by its ability to bind and aggregate bacteria, a function termed "immune exclusion." The present study was done to determine the effect of specific binding of sIgA to bacteria on the movement of these organisms across the intact epithelial membrane . STUDY DESIGN: Bacterial translocation across intact intestinal segments of rats were assessed in vitro using the Ussing model . Secretory IgA (0.25 mg per mL) from pooled human colostrum was added to the perfused segments of ileum in the Ussing system . Subsequently, the membranes were exposed to 5 x 10(9) cfu per mL Escherichia coli on their mucosal side . A second experiment tested the effect of human IgG when perfused with E . coli using the same preparation . All experiments had paired matched rats in a control group without immunoglobulin . The ability of sIgA and IgG to bind to E . coli was studied by an in vitro assay, as well as by transmission electron microscopy and immunofluorescence of random IgA/E . coli experiments . Measurements obtained in all experimental and control groups were the incidence and amount of bacterial passage and the potential difference generated by the intestinal segments (an index of viability) . RESULTS: There were no differences in potential difference between control and experimental groups in either of the two experiments . Secretory IgA bound E . coli and completely prevented passage of E . coli as compared with rats in the control group . IgG bound E . coli; however, the incidence of passage was equal to that of rats in the control group . However, the presence of IgG resulted in a significantly reduced number of bacteria that passed when compared with controls (p < 0.05) . Electron microscopic studies revealed intact surface morphology and immunofluorescence revealed aggregates of IgA and E . coli on the mucosal, but not submucosal, surface of the ileal membranes . CONCLUSIONS: This study provides direct evidence of immune exclusion by sIgA . When bound to bacteria, it prevents passage across a morphologically intact segment of viable intestinal tissue.

Appl Environ Microbiol, 1994 Dec, 60(12), 4239 - 44
Cloning of an insecticidal cholesterol oxidase gene and its expression in bacteria and in plant protoplasts; Corbin DR et al.; We cloned and sequenced structural gene choM, which encodes an insecticidally active cholesterol oxidase in Streptomyces sp . strain A19249 . The primary translation product was predicted to be a 547-amino-acid protein whose first 43 amino acids constitute a secretory signal peptide . Expression of the gene with the signal sequence in Escherichia coli resulted in production of a protein that had enzymatic and insecticidal properties which were indistinguishable from those of the cholesterol oxidase secreted by Streptomyces sp . strain A19249 . Expression of the gene with or without the signal sequence in tobacco protoplasts resulted in production of an enzymatically active cholesterol oxidase.

Biodegradation, 1994 Dec, 5(3-4), 175 - 84
Molecular genetics of carbon-phosphorus bond cleavage in bacteria; Wanner BL; Phosphonates (Pn) are a large class of organophosphorus molecules that have direct carbon-phosphorus (C-P) bonds in place of the carbon-oxygen-phosphorus ester bond . In bacteria two pathways exist for Pn breakdown for use as a P source: the phosphonatase and C-P lyase pathways . These pathways differ both in regard to their substrate specificity and their cleavage mechanism . The phosphonatase pathway acts on the natural Pn alpha-aminoethylphosphonate (AEPn) . In a two-step process it leads to cleavage of the C-P bond by a hydrolysis reaction requiring an adjacent carbonyl group . In contrast the C-P lyase pathway has a broad substrate specificity . It leads to cleavage of substituted Pn (such as AEPn) as well as unsubstituted Pn by a mechanism involving redox or radical chemistry . Due to its broad substrate specificity, the C-P lyase pathway is generally thought to be responsible for the breakdown of Pn herbicides (such as glyphosate) by bacteria . As a way to gain a more in-depth understanding of these Pn degradative pathways, their respective genes have been isolated and characterized . In the absence of a biochemical assay for the C-P lyase pathway such molecular approaches have been especially valuable . The roles of individual genes have been inferred from DNA sequence analysis and mutational effects . Genes for the C-P lyase pathway exist in a fourteen-gene operon that appears to encode both a binding protein-dependent Pn transporter and a C-P lyase . Genes for the phosphonatase pathway also exist in a gene cluster containing Pn uptake and degradative genes . A combination of biochemistry, molecular biology, and molecular genetics approaches has provided more detailed understanding of the mechanisms of C-P bond cleavage . Such basic information may provide a new handle for improvement of Pn degradation capabilities in bacteria, or in other cells in which the respective genes may be introduced and expressed.

Biotechnology (N Y), 1994 Dec, 12(13), 1376 - 8
A carbohydrate biosensor surface for the detection of uropathogenic bacteria; Nilsson KG et al.; We have developed a new surface for use in biosensors that is based on a gold plate covered with a specific carbohydrate receptor structure . The carbohydrate, Gal alpha 1-4Gal, was bound covalently via a thioalkylcarboxy-spacer, or adsorbed as a neoglycoprotein, to a two-dimensional gold surface . Both types of surfaces showed high specificity in the binding of the uropathogenic bacteria P-fimbriated Escherichia coli compared to the binding of non-infectious bacteria . The signal to noise ratio is sufficiently high to allow specific detection of the bacteria in biosensor applications.

Br J Theatre Nurs, 1994 Dec, 4(9), 10 - 3
Damp dusting in the operating theatre: implications for bacteria counts; Mackrodt K; This paper describes a research study replicating and expanding on Pickering's paper on damp dusting and its effect on bacteria counts, which concluded that there had been little difference in the counts for both the damp dusting and non-damp dusting period . However there were unexplained fluctuations in levels of bacteria that the author could not explain . A recommendation of the study was to try to ascertain whether damp dusting alters airborne concentrations or whether it is a combination of other variables . This study hoped to explain this.

Appl Environ Microbiol, 1994 Dec, 60(12), 4461 - 7
Phylogenetic analysis of a highly specific association between ectosymbiotic, sulfur-oxidizing bacteria and a marine nematode; Polz MF et al.; The phylogenetic relationship of chemoautotrophic, sulfur-oxidizing, ectosymbiotic bacteria growing on a marine nematode, a Laxus sp . (formerly a Catanema sp.), to known endosymbionts and free-living bacteria was determined . Comparative 16S rRNA sequencing was used to investigate the unculturable nematode epibionts, and rRNA-targeted oligonucleotide hybridization probes were used to identify the ectosymbionts in situ . Both analyses revealed a remarkably specific and stable symbiosis . Unique hybridization of a specific probe to the ectosymbionts indicated that only one species of bacteria was present and growing on the cuticle of the nematode . Distance and parsimony methods used to infer phylogenetic trees both placed the nematode ectosymbionts at the base of a branch containing chemoautotrophic, sulfur-oxidizing endosymbionts of three bivalve families and of the tube worm Riftia pachyptila . The most closely related free-living bacteria were chemoautotrophic sulfur oxidizers belonging to the genus Thiomicrospira . Furthermore, our results suggested that a second, only distantly related group of thioautotrophic endosymbionts has as its deepest branch surface-colonizing bacteria belonging to the genus Thiothrix, some of which are capable of sulfur-oxidizing chemoautotrophic growth.

Infect Immun, 1994 Dec, 62(12), 5205 - 12
Effects of cytokines and periodontopathic bacteria on the leukocyte function-associated antigen 1/intercellular adhesion molecule 1 pathway in gingival fibroblasts in adult periodontitis; Hayashi J et al.; We investigated the effects of inflammatory cytokines and periodontopathic bacteria on expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1, and E-selectin (endothelial leukocyte adhesion molecule 1) in cultured human gingival fibroblasts (HGF) . Cell surface ICAM-1 was upregulated on HGF under transcriptional control by exposure not only to interleukin-1 beta, tumor necrosis factor alpha, and gamma interferon but also to sonic extracts prepared from Porphyromonas gingivalis and Prevotella intermedia (nigrescens) and lipopolysaccharides from Escherichia coli . However, these stimuli induced only minimal expression of vascular cell adhesion molecule 1 and E-selectin on HGF . Binding assays using HGF and Molt 4, the human T-cell leukemia cell line, showed induced ICAM-1 to be functional, and the increased binding was blocked by a combination of monoclonal antibodies against ICAM-1 and leukocyte function-associated antigen 1 . Furthermore, gingival tissues from adult periodontitis patients showed increased mRNA expression of ICAM-1 compared with that in tissues from normal healthy donors . In immunohistological analysis, we also observed in vivo that the expression of ICAM-1 on fibroblasts in adult periodontitis tissues was greater than that in normal gingiva . Thus, the overexpression of ICAM-1 on gingival fibroblasts induced by cytokines and periodontopathic bacteria is speculated to be deeply involved in the accumulation and retention of leukocyte function-associated antigen 1-bearing leukocytes in adult periodontitis lesions.

Biochem Biophys Res Commun, 1994 Nov 30, 205(1), 558 - 64
The nucleotide and deduced amino-acid sequences of a cDNA encoding lactate dehydrogenase from Caenorhabditis elegans: the evolutionary relationships of lactate dehydrogenases from mammals, birds, amphibian, fish, nematode, plants, bacteria, mycoplasma, and plasmodium; Tsoi SC et al.; The nucleotide and deduced amino-acid sequences of a cDNA encoding L-lactate dehydrogenase (LDH) from nematode, Caenorhabditis elegans, were reported . This first invertebrate LDH sequence of 333 amino acids, including the initiation methionine, exhibits 63% identity with that of the most primitive vertebrate lamprey . The evolutionary relationships among 36 LDH isozymes from mammals, birds, amphibian, fish, nematode, plants, bacteria, mycoplasma and plasmodium were analyzed . The invertebrate nematode LDH is evolutionarily positioned between plant LDH and mammalian testicular LDH-C isozymes . The mammalian LDH-C isozyme appears to have arisen after the invertebrate LDH, but prior to the divergence of vertebrate LDH-A (muscle) and LDH-B (heart) isozymes as described previously.

Can J Microbiol, 1994 Nov, 40(11), 955 - 64
Characterization of the diversity of sulfate-reducing bacteria in soil and mining waste water environments by nucleic acid hybridization techniques; Telang AJ et al.; Nucleic acid hybridization techniques were used to characterize the sulfate-reducing bacterial communities at seven waste water and two soil sites in Canada . Genomic DNA was obtained from liquid enrichment cultures of samples taken from these nine sites . The liquid enrichment protocol favored growth of the sulfate-reducing bacterial component of the communities at these sites . The genomic DNA preparations were analyzed with (i) a specific gene probe aimed at a single genus (Desulfovibrio), (ii) a general 16S rRNA gene probe aimed at all genera of sulfate-reducing bacteria and other bacteria, and (iii) whole genome probes aimed at specific bacteria . This three-pronged approach provided information on the sulfate-reducing bacterial community structures for the nine sites . These were compared with each other and with the sulfate-reducing bacterial communities of western Canadian oil field production waters, studied previously . It was found that there is considerable diversity in the sulfate-reducing bacterial community at each site . Most sulfate-reducing bacteria isolated from distinct sites are genomically different and differ also from sulfate-reducing bacteria found in oil field production waters.

Zentralbl Bakteriol, 1994 Nov, 281(4), 415 - 32
Characterization of the specific antigenicity of representatives of M . senegalense and related bacteria; Besra GS et al.; Representative strains of M . senegalense and an unusual strain, labelled M . farcinogenes (M280) were examined by thin-layer chromatography for the presence of characteristic surface glycolipids . In the case of M . farcinogenes M280 and M . senegalense M264, the glycolipids were of the alkali-labile acyltrehalose lipooligosaccharide (LOS) class of antigens, whereas M . senegalense M263 was found to contain the alkali-stable glycopeptidolipids (GPL) . Through a combination of 1H-NMR, methylation analysis, FAB/MS, and other analytical techniques, the structures of these glycolipids were deduced . The LOS glycolipids were found to be similar in structure to the characteristic glucosyltrehalose-based glycolipids isolated previously from clinical isolates of M . fortuitum, but distinct from the diacyltrehaloses characteristic of the type strain of M fortuitum . The glycopeptidolipids from M . senegalense M263 were closely similar to those characterized previously from M.

EMBO J, 1994 Oct 3, 13(19), 4629 - 35
Self-splicing group I intron in cyanobacterial initiator methionine tRNA: evidence for lateral transfer of introns in bacteria; Biniszkiewicz D et al.; A group I self-splicing intron has been found in the anticodon loop of tRNA(fMet) genes in three cyanobacterial genera: Dermocarpa, Scytonema and Synechocystis; it is absent in nine others . The Synechocystis intron is also interrupted by an open reading frame (ORF) of 150 codons . Of these three bacteria, only Scytonema also contains the group I intron that has previously been reported in tRNA(Leu) (UAA) genes in both cyanobacteria and chloroplasts . The presence of an ORF in the tRNA(fMet) intron, the sporadic distribution of the intron among cyanobacteria and the lack of correlation between relatedness of the intron sequences and the bacteria in which they reside, are all consistent with recent introduction of this intron by lateral transfer.

FEMS Microbiol Rev, 1994 Oct, 15(2-3), 239 - 49
Genetic adaptation of bacteria to chlorinated aromatic compounds; van der Meer JR; Genetic mechanisms in bacteria provide a continuous source of alterations in DNA sequences that may lead to favourable adaptations . Bacteria that use chlorinated aromatics as sole carbon and energy sources show evidence of these different genetic alterations . The distinct effects of single base-pair mutations on adaptation of bacterial strains (e.g . by changing the substrate specificity of a key metabolic enzyme or regulator protein) have been demonstrated in various studies . In addition to these small sequence modifications, intermolecular or intercellular gene exchange mechanisms can result in new strains with altered metabolic capabilities . The details of these evolutionary processes with respect to the metabolism of chlorobenzenes and chlorocatechols are reviewed in this manuscript.

Arch Surg, 1994 Oct, 129(10), 1063 - 6
Translocation of bacteria and endotoxin in organ donors; van Goor H et al.; OBJECTIVE: To determine if bacterial translocation and endotoxin absorption occur in organ donors with an anatomically intact gastrointestinal tract . DESIGN: Case series . SETTING: Intensive care units in general and university hospitals . PATIENTS: Twenty-one (multiple) organ donors . INTERVENTION: None . MAIN OUTCOME MEASURES: Occurrence of factors that may promote bacterial translocation and/or endotoxin absorption . Bacterial concentration in mesenteric lymph nodes, abdominal fluid, blood, liver, lung, and spleen . Endotoxin level in abdominal fluid, peripheral blood, and portal blood . Anatomical integrity of the bowel wall . RESULTS: Factors that may promote bacterial translocation and/or endotoxin absorption were present in all organ donors . Culture specimens revealed bacteria in 14 organ donors (67%) . In 210 (81%) of 260 culture specimens, the bacteria isolated were identical to those isolated from the bowel content, demonstrating bacterial translocation . Endotoxin was found in nine (53%) of 17 abdominal fluid samples, in four (19%) of 21 peripheral blood samples, and in two (10%) of 21 portal blood samples . Light- and electron-microscopic examination of the bowel wall showed no anatomical abnormalities . CONCLUSION: Bacterial translocation and endotoxin absorption are frequent among organ donors and may adversely influence organ function in transplant recipients and other critically ill patients.

Curr Biol, 1994 Oct 1, 4(10), 920 - 2
Evolution . Archaea and eukaryotes versus bacteria?
Klenk HP, Doolittle WF.
The recent discovery of homologs of the eukaryotic transcription factor TATA-binding protein in archaea has been taken as support for the view that archaea and eukaryotes have a close phylogenetic relationship.

J Pediatr Surg, 1994 Oct, 29(10), 1348 - 51
Colonization of intestinal bacteria in the normal neonate: comparison between mouth and rectal swabs and small and large bowel specimens; Van Camp JM et al.; Seventy-four New Zealand white rabbit pups were divided into four groups: group I, 2 days of age (n = 9); group II, 3 to 5 days of age (n = 24); group III, 6 to 8 days of age (n = 27); and group IV, 10 to 13 days of age (n = 14) . Mouth swabs (MS), rectal swabs (RS), small bowel specimens (SB), and large bowel specimens (LB) were obtained from each rabbit, incubated for 24 hours in thioglycolate broth, and plated on blood agar in aerobic and anaerobic environments . After 24 hours, growth on blood agar plates were observed . All MS specimens and all but one RS specimen showed positive growth . Growth of both LB and SB specimens increased significantly with age (P < .04) . In addition, SB growth was significantly less than RS or MS growth in groups I, II, and III (P < .05) . LB growth was significantly less than RS or MS growth in group I (P < .01) and tended to be less in groups II and III (62.5% v 100% and 93% v 100%, respectively) . These data show that nearly half of normal rabbits under 6 days of age have sterile small and large intestines despite almost 100% growth from rectal and mouth swabs . These findings partially explain the absence of spontaneous bacterial translocation in young rabbit pups (under 4 days of age) and have important implications for the prophylaxis and treatment of neonatal sepsis.

Zhonghua Wai Ke Za Zhi, 1994 Oct, 32(10), 615 - 8
{Relationship between gut origin bacteria and wound infection after thermal injury}; Fu WL et al.; The pUC19 plasmid vector trace with restriction map analysis and fluorescence labelling bacteria method were applied to study the relationship between the gut origin bacteria and wound infection . According to the characteristic of pUC19 plasmid, a special animal model was designed . 110 Wistar rats received 30% TBSA full thickness burns . On hours 6, 12, 24, 48 and day 12 postburn, injured animal were killed . Subeschar tissue homogenates were examined under fluorescence microscope, and bacterial culture, isolation of plasmids and restriction map analysis were also carried out . The results show that during early stage of burns, 32.5% of fluorescence labelling bacteria and 10.81% of pUC19 plasmid vectors could be detected from the subeschar specimens . 12 day postburn, the detectable rage of pUC19 plasmid vector increased to 62.5% . Beside the factor of early colonization, the contaminative route form gut perineum and then wounds should be considered.

Proc Natl Acad Sci U S A, 1994 Sep 27, 91(20), 9392 - 6
Evolutionary relationships of lactate dehydrogenases (LDHs) from mammals, birds, an amphibian, fish, barley, and bacteria: LDH cDNA sequences from Xenopus, pig, and rat; Tsuji S et al.; The nucleotide sequences of the cDNAs encoding LDH (EC 1.1.1.27) subunits LDH-A (muscle), LDH-B (liver), and LDH-C (oocyte) from Xenopus laevis, LDH-A (muscle) and LDH-B (heart) from pig, and LDH-B (heart) and LDH-C (testis) from rat were determined . These seven newly deduced amino acid sequences and 22 other published LDH sequences, and three unpublished fish LDH-A sequences kindly provided by G . N . Somero and D . A . Powers, were used to construct the most parsimonious phylogenetic tree of these 32 LDH subunits from mammals, birds, an amphibian, fish, barley, and bacteria . There have been at least six LDH gene duplications among the vertebrates . The Xenopus LDH-A, LDH-B, and LDH-C subunits are most closely related to each other and then are more closely related to vertebrate LDH-B than LDH-A . Three fish LDH-As, as well as a single LDH of lamprey, also seem to be more related to vertebrate LDH-B than to land vertebrate LDH-A . The mammalian LDH-C (testis) subunit appears to have diverged very early, prior to the divergence of vertebrate LDH-A and LDH-B subunits, as reported previously.

Proc Natl Acad Sci U S A, 1994 Sep 13, 91(19), 9037 - 41
Evidence for multiple adaptive peaks from populations of bacteria evolving in a structured habitat; Korona R et al.; Natural selection tends to promote the divergence of populations living in different environments . Even in identical environments, however, replicate populations may diverge if they find alternative adaptive solutions . We describe the evolution of 18 bacterial populations (Comamonas sp.) founded from a single progenitor genotype and propagated separately for 1000 generations in two distinct environments, one physically unstructured (mass-action liquid) and the other structured (agar surfaces) . Phenotypic diversity, as reflected in colony morphology, was greater in the structured habitat than in the unstructured habitat . More importantly, the trajectories for mean fitness, as measured by competition against the common ancestor, were more divergent for populations in the structured habitat than those in the unstructured habitat . Structured environments may accelerate evolutionary diversification by promoting genetic polymorphisms within populations, thereby increasing the complexity of genetic constraints that allow divergence among replicate populations.

Gut, 1994 Sep, 35(9), 1271 - 4
In vitro acetaldehyde formation by human colonic bacteria; Jokelainen K et al.; Incubation of human colonic contents with various ethanol concentrations (2.75-44 mM) in vitro at 37 degrees C resulted in significant accumulation of acetaldehyde--a toxic and highly reactive compound . At pH 9.6, all samples produced notable acetaldehyde concentrations (58 (13) microM; mean (SEM)) even from the lowest (2.75 mM) ethanol concentration, and the production of acetaldehyde increased lin-early with rising ethanol concentration (r = 0.97; p < 0.005), reaching a peak concentration of 238 (37) microM at 44 mM ethanol . The formation of acetaldehyde took place rapidly, as almost 50% of acetaldehyde formed during the total eight hour incubation was detectable after one hour, and 75% of the total after four hours . Maximal acetaldehyde production from 22 mM ethanol occurred at pH 9.6 (160 (35) microM) but appreciable concentrations were also seen at pH 7.4 (110 (38) microM) and pH 6.0 (63 (19) microM) . At pH 4.0, by contrast, acetaldehyde formation was negligible (17 (5) microM) . 4-Methylpyrazole, a potent inhibitor of alcohol dehydrogenase, showed a decreasing effect on acetaldehyde production in vitro but first at a concentration of 100 mM . Considerable acetaldehyde production by human colonic bacteria--if it occurs also in vivo--could constitute a risk factor for rectal cancer in heavy drinkers and also provide a pathogenetic mechanism for alcohol induced diarrhoea.

Microbiology, 1994 Sep, 140 ( Pt 9), 2349 - 54
Evolutionary relationships between sugar kinases and transcriptional repressors in bacteria; Titgemeyer F et al.; We have characterized a new family of proteins (the ROK family) which includes six transcriptional repressors for sugar catabolic operons, three sugar kinases, and three unidentified open reading frames . Analysis of the aligned sequences and phylogenetic tree construction allow predictions regarding the functional nature of conserved domains and residues within these proteins as well as the pathway of evolutionary divergence that gave rise to the family.

FEMS Microbiol Lett, 1994 Sep 1, 121(3), 303 - 7
Detection of stress proteins in Porphyromonas gingivalis and other oral bacteria by western immunoblotting analysis; Vayssier C et al.; Detection of stress proteins in Porphyromonas gingivalis was investigated by SDS-PAGE and Western immunoblotting procedure using a polyclonal antibody (anti hsp60) and a monoclonal antibody (anti-Dnak) . Results indicate that P . gingivalis can elicit a hsp60-like stress protein when submitted to different environmental stresses such as a heat shift from 35 degrees C to 43 degrees C, a pH drop from 7.2 to 6.0 or an increase in oxygen concentration . Virulent and non-virulent strains of P . gingivalis responded the same way . The other bacterial species tested also showed an increased synthesis of a GroEL-like protein after heat shock, as detected by the anti hsp60 antibody . However, the monoclonal anti-Dnak recognized an hsp70-like protein only in two of the tested species.

Mol Gen Mikrobiol Virusol, 1994 Sep-Oct, (5), 17 - 21
{Cloning and identification of the gene controlling nitrogen metabolism in the photosynthetic purple bacteria Rhodobacter sphaeroides}; Glazer VM et al.; A recombinant plasmid has been selected from the genomic library of Rhodobacter sphaeroides that restores the properties of the wild type strain in the mutant Drn121 . The latter possesses the derepressed synthesis of nitrogenase when grown in the light, inability of nitrogen fixation in the dark and growth on potassium nitrate as a single source of nitrogen, disruption of ammonium ions and methylamine transportation, decreased activity of glutamine synthetase . The gene complementing the drn121 mutation is localized within the EcoRI-HindIII fragment of Rhodobacter sphaeroides chromosome 2.25 kb in size . Analysis of the fragment nucleotide sequence has revealed the fragments with a high level of homology to regulatory genes ntrB (the 3'-end) and ntrC of Rhodobacter capsulatus . The plasmid pRCN102, containing the nifR3-ntrB-ntrC operon of Rhodobacter capsulatus, is able to complement the drn121 mutation while its derivatives having inactivated ntrN or ntrC genes are not . Hence, in Rhodobacter sphaeroides mutant Drn121 the mutation is localized in ntrC gene the product of which is involved not only in nitrogen fixation but also in nitrogen metabolism on the whole.

Biol Pharm Bull, 1994 Sep, 17(9), 1277 - 81
Mechanism of an early lysis by fatty acids from axenic Phormidium tenue (musty odor-producing cyanobacterium) and its growth prolongation by bacteria; Yamada N et al.; We have previously demonstrated that bacteria-containing Phormidium tenue, a cyanobacterium which produces musty odor 2-methylisoborneol, grew beyond 8 weeks, whereas axenic alga perished suddenly between the 3rd week and the 4th week while being cultured in the laboratory . This mechanism was investigated . It is assumed that when algal cells grow beyond a certain level, the supply of CO2 becomes inadequate and results in the rapid lysis of axenic alga . At that time, inhibitory substances liberated from algal cells kill the surviving alga . Since the process occurs continuously, this alga is finally annihilated . On the other hand, since inhibitory substances are metabolized or degraded by bacteria coexistent with alga, bacteria-containing P . tenue maintains growth for a long time . The growth-inhibitory substance was found to be unsaturated free fatty acids.

Trends Microbiol, 1994 Sep, 2(9), 329 - 32
Role of bacteria-specific T cells in the immunopathogenesis of reactive arthritis; Probst P et al.; Reactive arthritis is a usually self-limited sterile inflammation of joints that follows certain bacterial gastrointestinal or urogenital infections . The immunopathogenesis involves CD4+ T cells, which mediate an antigen-specific TH1 response to bacterial constituents within the joint . Properties of the arthritogenic bacteria and the physicochemical characteristics of the bacterial antigens may contribute to the development of reactive arthritis.

Izv Akad Nauk Ser Biol, 1994 Sep-Oct, (5), 810 - 7
{The participation of vaginal bacteria in Phodopus campbelli in the chemical communication between male and female}; Sokolov VE et al.; Phodopus campbelli commonly occurs in dry steppe and semidesert zone of south Siberia, Mongolia and China . Using radiotelemetry we found that a male has to cover about 2 km from his burrow to encounter a receptive female . Female in estrus marks a small area around its burrow by vaginal smear . Experiments were carried out in laboratory to discover the nature of this strong signal . In a "open field" area four boxes within stimuli we recorded the time complemented spent by males near boxes to study the attractive effect of intact receptive female, germ culture of vaginal smear and artificial mixed culture of bacteria which were found in the vaginal smear of Ph . campbelli receptive female . Males (n = 15) spent significantly more time near the boxes with female in estrus or day before estrus as compared with two other days of cycle . Germ culture from vaginal smear sampled on the estrus day was more attractive to males on 6th day than on the 2, -3, -5, -7, -8--or 9th days of cultivation, pure culture or germ culture sampled on anestrus . Mixed culture, which simulated the proportion of predominant bacteria in the estrus vaginal smear, was significantly more attractive for males on the 3rd day of cultivation . Thus sexual attractant of Ph . campbelli could be produced by some bacteria located in the vagina in estrus and it takes a couple of days of cultivation for maximum attractive effect.

J Mol Biol, 1994 Aug 12, 241(2), 233 - 45
The major dimerization determinants of the nitrogen regulatory protein NTRC from enteric bacteria lie in its carboxy-terminal domain; Klose KE et al.; The NTRC protein (nitrogen regulatory protein C) of enteric bacteria is an enhancer-binding protein that activates transcription by the sigma54-holoenzyme form of RNA polymerase . NTRC is a homodimeric protein that binds to a dyad-symmetrical site in DNA . To activate transcription NTRC must be phosphorylated and must form an appropriate oligomeric species at an enhancer . In order to study subunit exchange between NTRC dimers, we constructed a fusion of the maltose-binding protein (MBP) to the amino-terminal end of NTRC (MBP-NTRC) and visualized the formation of heterodimers between MBP-NTRC and wild-type NTRC by a gel-mobility shift assay for DNA-binding . When MBP-NTRC is mixed with wild-type NTRC at 37 degrees C, subunit exchange occurs rapidly . The apparent half-life for dissociation of homodimers of NTRC is two to three minutes at 37 degrees C and is not changed by phosphorylation . The isolated carboxy-terminal domain of NTRC (91 amino acid residues) forms heterodimers with both wild-type NTRC and MBP-NTRC, indicating that the C-terminal domain is sufficient for dimerization . The apparent rate of dissociation of homodimers of the C-terminal domain is essentially the same as that of full-length NTRC, indicating that the major dimerization determinants of the protein lie in its C-terminal domain . Congruent with this, a truncated form of NTRC from which the last 58 amino acid residues were removed is a monomer in solution . Moreover, truncated forms of NTRC from which the last 16 or 26 amino acid residues were removed are predominantly monomeric in solution, as is a mutant form with the amino acid substitution A410E in its C-terminal domain . Monomerization of the above mutant forms of NTRC can be rationalized on the basis of homology between the C-terminal region of NTRC and a 50 amino acid residue region of the factor for inversion stimulation (FIS) protein.

Appl Environ Microbiol, 1994 Aug, 60(8), 2736 - 45
Influence of substrate diffusion on degradation of dibenzofuran and 3-chlorodibenzofuran by attached and suspended bacteria; Harms H et al.; Dibenzofuran uptake-associated kinetic parameters of suspended and attached Sphingomonas sp . strain HH19k cells were compared . The suspended cells were studied in a batch system, whereas glass beads in percolated columns were used as the solid support for attached cells . The maximum specific activities of cells in the two systems were the same . The apparent half-maximum uptake rate-associated concentrations (Kt') of attached cells, however, were considerably greater than those of suspended cells and depended on cell density and on percolation velocity . A mathematical model was developed to explain the observed differences in terms of substrate transport to the cells . This model was based on the assumptions that the intrinsic half-maximum uptake rate-associated concentration (Kt) was unchanged and that deviations of Kt' from Kt resulted from the stereometry and the hydrodynamics around the cells . Our calculations showed that (i) diffusion to suspended cells and to single attached cells is efficient and therefore only slightly affects Kt'; (ii) diffusion to cells located on crowded surfaces is considerably lower than that to single attached cells and greatly increases Kt', which depends on the cell density; (iii) the convective-diffusive transport to attached cells that occurs in a percolated column is influenced by the liquid flow and results in dependency of Kt' on the flow rate; and (iv) higher specific affinity of cells correlates with higher susceptibility to diffusion limitation . Properties of the experimental system which limited quantitative proof of exclusively transport-controlled variations of Kt' are discussed.

Biopolymers, 1994 Aug, 34(8), 1049 - 58
Morphology and primary crystal structure of a silk-like protein polymer synthesized by genetically engineered Escherichia coli bacteria; Anderson JP et al.; The morphology and primary crystal structure of SLPF, a protein polymer produced by genetically engineered Escherichia coli bacteria, were characterized . SLPF is a segmented copolymer consisting of amino acid sequence blocks modeled on the crystalline segments of silk fibroin and the cell attachment domain of human fibronectin . Wide angle x-ray scattering (WAXS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and molecular simulations were used to analyze the primary crystal structure of SLPF . TEM experiments conducted on SLPF droplets cast from formic acid on amorphous carbon film demonstrated that these protein films have a microstructure formed of woven sheaves . The sheaves are composed of well-defined whisker crystallites . The width of the whiskers, 11.8 +/- 2.2 nm, may be correlated to the length of the silk-like segment in SLPF as predicted by molecular simulations . WAXS data, TEM images, SAED, patterns, molecular simulations, and theoretical diffraction patterns all were consistent with the crankshaft model proposed for Silk I by Lotz and Keith.

J Immunol Methods, 1994 Aug 1, 173(2), 149 - 56
A two fusion partner system for raising antibodies against small immunogens expressed in bacteria; Hey AW et al.; Production of antisera against proteins that are not amenable to easy purification is most efficiently achieved by expressing the protein as a fusion product in bacteria . However, smaller polypeptides may present difficulties, since the majority of the antibodies may be directed against the fusion partner if the whole fusion protein is used as immunogen, while the target peptide alone may be a poor immunogen due to its small size . We have circumvented this problem through the use of two different fusion partners . The first fusion protein is used for priming the immune response and the first boost, while another fusion partner is substituted for the second boost . Five different polypeptides derived from the human polyomavirus BK, ranging in molecular weight from 4400 (39 amino acid residues) to 11,500 (96 amino acid residues), were used to test this approach . The results obtained indicate that this procedure may be very useful in raising antibodies against small antigens.

J Mol Endocrinol, 1994 Aug, 13(1), 11 - 21
Overexpression of the extracellular domain of the thyrotrophin receptor in bacteria; production of thyrotrophin-binding inhibiting immunoglobulins; Costagliola S et al.; The availability of high affinity antibodies to the human TSH receptor (TSHR) would help in defining its functional domains, but this requires the production of pure receptor as immunogen . We have expressed the extracellular domain (ECD) of the TSHR (residues 21-414) as a fusion protein with maltose-binding protein (MBP) in Escherichia coli, using the pMAL-cR1 vector . The major protein in an electrophoretically separated, crude bacterial lysate had a molecular mass of 89 kDa, in agreement with the size predicted for the MBP-ECD fusion product . Its identity was confirmed by Western blotting in which it was recognized by two polyclonal antibodies to synthetic peptides of the TSHR and an anti-MBP . Following purification on an amylose column, 15 mg pure MBP-ECD per litre of culture were produced, which was 5% of the total bacterial protein . Following extensive dialysis in a buffer which produces slight denaturation, MBP-ECD was cleaved with factor Xa . The identity of each protein was confirmed by Western blotting . To investigate the possibility of using the fusion protein as an immunogen we produced rabbit polyclonal antibodies to the ECD which were able to produce immunofluorescent staining of Chinese hamster ovary cells that expressed the TSHR, and revealed a protein of 95 kDa in Western blots of the same cells, in addition to a protein of 55 kDa . Only the protein of 55 kDa was detected in Western blots of human thyroid membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Curr Opin Neurobiol, 1994 Aug, 4(4), 474 - 80
Chemosensing and signal transduction in bacteria; Stock J et al.; Major advances have been made over the past year in understanding the molecular mechanisms involved in membrane receptor function, and in resolving the global organization of intracellular signaling pathways . Crystallographic and biochemical studies are revealing details of transmembrane signaling mechanisms and the phosphorylation reactions of the two-component regulatory systems . In addition, the discovery of new signal transduction pathways and new inputs into known pathways are providing a clearer view of the basic architecture of the signal transduction networks within the bacterial cell.

Biochemistry, 1994 Jul 12, 33(27), 8306 - 12
Interaction between cytochrome c2 and reaction centers from purple bacteria; Wang S et al.; The kinetics of electron transfer of cytochrome c2 from Rhodobacter sphaeroides, Rhodobacter capsulatus, and Rhodospirillum centenum to reaction centers from Rb . sphaeroides and Rb . capsulatus have been measured . Observed in the kinetics of decay of the oxidized donor are a rapid first-order rate and one or more slower rates that are due to diffusion-limited complex formation . For reaction centers from Rb . sphaeroides, the fast component had time constants of 1.0 and 0.5 microsecond for cytochrome c2 from Rb . sphaeroides and Rb . capsulatus, respectively, but only a slow component was observed for cytochrome c2 from Rs . centenum . For reaction centers from Rb . capsulatus, the kinetics from all three cytochromes had a fast component with time constants of 1.0, 0.7, and 1.9 microseconds for cytochrome c2 from Rb . sphaeroides, Rb . capsulatus, and Rs . centenum, respectively, although the dissociation constant for cytochrome c2 from Rs . centenum was approximately 20 times larger than that of the other cytochromes . The observation of the fast component for cytochrome c2 from Rs . centenum in reaction centers from Rb . capsulatus but not Rb . sphaeroides demonstrates that the binding interactions for the two reaction centers differ, and the involvement of amino acid residues in the binding is discussed . The kinetics of electron transfer from cytochrome c2 to reaction centers of Rb . sphaeroides from wild type and three mutant strains that have altered carboxyl-terminal regions of the M subunit of the reaction center have also been measured . For cytochrome c2 from Rb . sphaeroides, the kinetics are very similar between the mutants and wild type.(ABSTRACT TRUNCATED AT 250 WORDS)

Can J Microbiol, 1994 Jul, 40(7), 561 - 6
Construction of a DNA probe to detect isoquinoline-degrading bacteria; Richards NK et al.; To facilitate the cloning of DNA encoding isoquinoline degradation an assay was developed that allowed the rapid visual scoring of the isoquinoline degradation phenotype of single colonies . Transposon mutagenesis of one of the isolates . Comamonas acidovorans IQ3, was performed using Tn5, and nine Isq-mutants deficient in the ability to utilise isoquinoline as the sole nitrogen source were isolated . These mutants were also incapable of utilising the first metabolite of the isoquinoline degradation pathway, 1-hydroxyisoquinoline, as the sole carbon source . For each Isq-mutant, the EcoRI fragment containing the Tn5 insertion was cloned into pBR322 . Restriction and Southern analyses of the cloned DNA revealed that of the nine Isq-mutants, six contained Tn5 insertions in a common 8.9-kb EcoRI fragment derived from the wild type, C . acidovorans IQ3 . The cloned DNA thought to be involved in the degradation of isoquinoline proved to be specific when used as a probe in colony hybridization to some bacteria possessing the ability to degrade isoquinoline.

Biotechniques, 1994 Jul, 17(1), 144 - 6, 148-9
A molecular technique for identification of bacteria using small subunit ribosomal RNA sequences; Avaniss-Aghajani E et al.; We have recently developed a novel molecular technique for identification of specific bacterial species within a complex mixture . The technique uses PCR to amplify small subunit ribosomal RNA (SSU rRNA) genes from a mixture of bacteria . One of the PCR primers is labeled with a fluorescent dye to allow detection of the amplified product . The PCR product is then digested with restriction enzymes and a capillary electrophoresis unit equipped with a laser-induced fluorescence detector is employed to analyze the restriction fragments . Only restriction fragments that contain the fluorescent-labeled primer are detected . Generally, the nucleotide sequence of the SSU rRNA genes is unique for each bacterial species . Consequently, the fluorescent-labeled restriction fragments from different bacterial species often have characteristic lengths . Thus, the different fluorescent peaks that appear in a capillary electropherogram correspond to labeled restriction fragments from different bacterial species . This protocol allows us to identify a number of different bacterial species in a complex mixture . Only a minute sample of bacterial DNA and a minimal amount of time (8-10 h) are required for this analysis . The protocol is sensitive, rapid and capable of identifying a broad spectrum of bacterial species.

Adv Dent Res, 1994 Jul, 8(2), 285 - 90
Control of specific plaque bacteria; Russell RR; The Specific Plaque Hypothesis posits that particular bacteria are of unique importance in the etiology of dental caries and periodontal diseases, and a logical conclusion is that these bacteria should be the targets for our 'magic bullets' in devising plaque-control methods . This paper considers the development of preventive measures based on understanding of the significance of particular bacterial species and the properties of those bacteria . Knowledge of the importance of specific organisms as mediators of disease and molecular studies on the properties of potential virulence factors may reveal potential targets for inhibition, blocking by synthetic analogues, or functional inactivation by antibodies.

FEBS Lett, 1994 Jun 6, 346(1), 73 - 7
Protein translocation: common themes from bacteria to man; Jungnickel B et al.; Protein transport across the endoplasmic reticulum membrane in eukaryotes and across the cytoplasmic membrane in bacteria have turned out to be highly related . The core component of the translocation apparatus is the Sec61/SecYp complex; at least two of its subunits are conserved in evolution . The Sec61/SecYp complex is involved in both co- and post-translational transport pathways . The two modes require probably distinct additional components.

Science, 1994 Jun 3, 264(5164), 1460 - 3
Liquid-crystalline mesophases of plasmid DNA in bacteria; Reich Z et al.; Bacterial plasmids may often reach a copy number larger than 1000 per cell, corresponding to a total amount of DNA that may exceed the amount of DNA within the bacterial chromosome . This observation highlights the problem of cellular accommodation of large amounts of closed-circular nucleic acids, whose interwound conformation offers negligible DNA compaction . As determined by x-ray scattering experiments conducted on intact bacteria, supercoiled plasmids segregate within the cells into dense clusters characterized by a long-range order . In vitro studies performed at physiological DNA concentrations indicated that interwound DNA spontaneously forms liquid crystalline phases whose macroscopic structural properties are determined by the features of the molecular supercoiling . Because these features respond to cellular factors, DNA supercoiling may provide a sensitive regulatory link between cellular parameters and the packaging modes of interwound DNA in vivo.

J Infect Dis, 1994 Jun, 169(6), 1265 - 70
Virus and bacteria enhance histamine production in middle ear fluids of children with acute otitis media; Chonmaitree T et al.; Histamine levels were measured in 677 middle ear fluid (MEF) samples from 248 children (aged 2 months to 7 years) with acute otitis media (AOM); of these, 116 (47%) had documented viral infection . Histamine content was higher in bacteria-positive than in bacteria-negative MEF samples (P = .007) and higher in samples from patients with viral infection than in those from patients with no viral infection (P = .002) . Bacteria and viruses together had an additive effect on histamine content in MEF . Histamine concentration in the initial MEF sample tended to be higher in patients with persistent otitis than in those with good response to treatment (P = .14) . Results suggest that viruses, bacteria, or both induce histamine production, which leads to increased inflammation in the middle ear . Antihistaminic drugs may be beneficial . Large, prospective, controlled trials of the effects of antihistamine as an adjunct therapy in bacterial and viral AOM are required before recommendations can be made.

Gastroenterology, 1994 Jun, 106(6), 1405 - 17
Natural gastric infection with Helicobacter pylori in monkeys: a model for spiral bacteria infection in humans; Dubois A et al.; BACKGROUND/AIMS: There is no generally accepted model for Helicobacter pylori infection in humans . The aim of this study was to examine the natural history and effect of treatment in rhesus monkeys and sequentially define the immune response to H . pylori in relation to treatment . METHODS: Infection and gastritis were graded blindly by histological analysis and culture of biopsy specimens harvested during gastroduodenoscopies in 26 anesthetized colony-bred monkeys . Plasma H . pylori-specific immunoglobulin (Ig) G levels were determined by enzyme-linked immunosorbent assay . RESULTS: H . pylori and Gastrospirilum hominis-like organisms were present in 13 and 9 monkeys, respectively; 3 animals harbored both organisms, whereas 4 monkeys were not infected . Gastritis score was < or = 1.5 in animals uninfected or infected only with G . hominis-like organisms and > or = 2.0 in all H . pylori-infected animals . IgG ratios were > or = 0.5 in 12 of 13 H . pylori-infected animals and in 2 of 13 H . pylori-negative animals (P < 0.001) . One monkey became infected with H . pylori during the observation period, with concurrent increase of gastritis and plasma IgG levels . In untreated animals, infection, gastritis, and plasma IgG levels remained unchanged over 7-15 months . Triple therapy eradicated H . pylori at 6 months in 4 of 6 animals while suppressing gastritis and plasma IgG levels . CONCLUSIONS: Rhesus monkeys harboring H . pylori are persistently infected and have gastritis and elevated specific IgG levels, all of which may respond to appropriate therapy, whereas G . hominis infection is associated with little inflammation.

FEMS Microbiol Lett, 1994 Jun 1, 119(1-2), 199 - 207
Anaerobic degradation of halogenated benzoic acids by photoheterotrophic bacteria; van der Woude BJ et al.; From light-exposed enrichment cultures containing benzoate and a mixture of chlorobenzoates, a pure culture was obtained able to grow with 3-chlorobenzoate (3-CBA) or 3-bromobenzoate (3-BrBA) as the sole growth substrate anaerobically in the light . The thus isolated organism is a photoheterotroph, designated isolate DCP3 . It is preliminarily identified as a Rhodopseudomonas palustris strain . It differs from Rhodopseudomonas palustris WS17, the only other known photoheterotroph capable of using 3-CBA for growth, in its independence of benzoate for growth with 3-CBA and in its wider substrate range: if grown on 3-CBA, it can also use 2-CBA, 4-CBA or 3,5-CBA.

Hua Xi Yi Ke Da Xue Xue Bao, 1994 Jun, 25(2), 145 - 8
{Pathological study of enamel caries produced by oral bacteria in vitro}; Zhou X et al.; The authors used the bacterial culture method to study early enamel caries-like lesions in vitro . Pathologic changes in the lesions were observed under polarized light microscope and scanning electron microscope . The results showed that this method could simulate the destructive procedures in carious development . The destructive way and pathologic changes of the caries-like lesions were very similar to those of natural caries . Under microscope, the ultrastructures of the relatively intact layer of the enamel surfaces were already changed . The prisms in the enamel surfaces were destroyed, and dissolved to form small pores . The pores could be an important path of the carious development.

Mol Gen Mikrobiol Virusol, 1994 May-Jun, (3), 23 - 5
{Expression of the gene for the gp46 surface glycoprotein from the human T-cell leukemia virus type I (HTLV-I) in bacteria}; Sankov MN et al.; A set of recombinant plasmids containing different fragments of HTLV-I env gene has been constructed on the basis of pUR290-pUR292 vectors . The hybrid proteins containing different fragments of ENV predecessor in the C-terminal of beta-galactosidase differed in stability in Escherichia coli cells . The presence of N-terminal of ENV predecessor in recombinant proteins considerably decreases their resistance to proteases of the bacterial cell . Elimination of this fragment led to obtaining of the recombinant plasmid pESG coding for the high level of synthesis of the env-specific hybrid polypeptide (up to 30% of the total cellular protein) . This 134 Kda protein is able to interact efficiently with the HTLV-I positive sera and may be used in the diagnostic test-systems for identification of the HTLV-I infected patients.

J Clin Microbiol, 1994 May, 32(5), 1354 - 6
Mycobacterium smegmatis strain for detection of Mycobacterium tuberculosis by PCR used as internal control for inhibition of amplification and for quantification of bacteria; Kolk AH et al.; For the detection of Mycobacterium tuberculosis by PCR, the IS6110 sequence was used . A modified target was constructed by insertion of 56 nucleotides in the IS6110 insertion element of Mycobacterium bovis BCG . This modified insertion sequence was integrated into the genome of Mycobacterium smegmatis, a mycobacterium species which does not contain the IS6110 element . When DNA from the modified M . smegmatis 1008 strain was amplified with IS6110-specific primers INS1 and INS2, a band of 301 bp was seen on agarose gel, whereas the PCR product of M . tuberculosis complex DNA was a 245-bp fragment with these primers . The addition of a small number of M . smegmatis 1008 cells to clinical samples before DNA purification enables the detection of problems which may be due to the loss of DNA in the isolation procedure or to the presence of inhibitors . The presence of inhibitors of the amplification reaction can be confirmed by the addition of M . smegmatis 1008 DNA after the DNA isolation procedure . Furthermore, competition between the different target DNAs of M . smegmatis 1008 DNA and M . tuberculosis complex DNA enables the estimation of the number of IS6110 elements in the clinical sample.

J Invertebr Pathol, 1994 May, 63(3), 275 - 84
Chemotaxis of Mercenaria mercenaria hemocytes to bacteria in vitro; Fawcett LB et al.; Hemocytes of the hard clam Mercenaria mercenaria migrate toward secreted bacterial products in vitro by chemotaxis (i.e., by detection of an increasing chemical gradient of attractant) . The attractants produced by Escherichia coli are peptides or small proteins . Clam hemocytes also migrate toward formyl-methionyl-leucyl-phenylalanine (fMLF), a mammalian neutrophil chemoattractant produced by bacteria, but not toward the related compound formyl-methionyl-valine . Migration of hemocytes to fMLF was blocked with the neutrophil fMLF receptor antagonist, t-Boc-MLF, suggesting that the hemocytes possess this receptor and that the response is receptor-mediated . However, fMLF is not the major bacterial chemoattractant for clam hemocytes, as t-Boc-MLF did not block migration of these cells to secreted bacterial chemoattractants.

J AOAC Int, 1994 May-Jun, 77(3), 623 - 7
Enumeration of total bacteria in raw and pasteurized milk by reflectance colorimetry: collaborative study; Richardson GH et al.; Seven out of 9 laboratories completed a collaborative study comparing a reflectance colorimetric (RC) bioactivity monitor (Omnispec 4000) method to the standard plate count (SPC) method for estimation of total bacteria in raw and homogenized pasteurized milk . Each laboratory analyzed 12 different samples by the SPC method and 24 samples (12 blind duplicates) by the RC method . For the RC method RSDr was 1.7%, and RSDR was 4.5% . RSDR for the SPC method was 20.8% . The method was adopted first action by AOAC INTERNATIONAL.

Proc Natl Acad Sci U S A, 1994 Apr 12, 91(8), 3117 - 21
Synthesis of circular RNA in bacteria and yeast using RNA cyclase ribozymes derived from a group I intron of phage T4; Ford E et al.; Studies on the function of circular RNA and RNA topology in vivo have been limited by the difficulty in expressing circular RNA of desired sequence . To overcome this, the group I intron from the phage T4 td gene was split in a peripheral loop (L6a) and rearranged so that the 3' half intron and 3' splice site are upstream and a 5' splice site and 5' half intron are downstream of a single exon . The group I splicing reactions excise the internal exon RNA as a circle (RNA cyclase ribozyme activity) . We show that foreign sequences can be placed in the exon and made circular in vitro . Expression of such constructs (RNA cyclase ribozymes) in Escherichia coli and yeast results in the accumulation of circular RNA in these organisms . In yeast, RNA cyclase ribozymes can be expressed from a regulated promoter like an mRNA, containing 5' leader and 3' trailer regions, and a nuclear pre-mRNA intron . RNA cyclase ribozymes have broad application to questions of RNA structure and function including end requirements for RNA transport or function, RNA topology, efficacy of antisense or ribozyme gene control elements, and the biosynthesis of extremely long polypeptides.

Clin Exp Immunol, 1994 Apr, 96(1), 91 - 7
Oral and aerosol immunization with viable or inactivated Actinobacillus pleuropneumoniae bacteria: antibody response to capsular polysaccharides in bronchoalveolar lavage fluids (BALF) and sera of pigs; Hensel A et al.; To investigate the antibody response after local application of lung-pathogenic bacteria, pigs were immunized with viable or inactivated Actinobacillus pleuropneumoniae by the oral and aerogenous route . After 3 weeks class-specific immunoglobulins against purified A . pleuropneumoniae capsular polysaccharides (CP) were determined in serum and BALF by ELISA . A significant increase of IgA antibodies was found in BALF but not in sera of all immunized pigs . Oral immunization with viable A . pleuropneumoniae and aerosol immunization with either viable or inactivated bacteria resulted in a significant increase of IgG antibodies to the CP antigen in BALF, whereas only aerosol exposure to viable bacteria resulted in a significant increase in IgG antibodies in serum . A significant increase in anti-CP IgM in BALF was observed after aerosol exposure but not after oral immunization . IgM antibodies towards CP increased significantly by both routes of immunization with viable bacteria . The anti-CP activity of all three isotypes in sera and BALF was low in all groups compared with the positive controls, although inoculation of viable A . pleuropneumoniae led to higher levels of antibody concentration than inactivated bacteria . Our results indicate a traffic of primed lymphocytes from the gut into the bronchoalveolar airways and further support the hypothesis that polysaccharide-specific B cells may functionally mature at the mucosal surfaces.

Mol Microbiol, 1994 Apr, 12(1), 153 - 63
A seven-gene operon essential for formate-dependent nitrite reduction to ammonia by enteric bacteria; Hussain H et al.; The DNA sequence of the regulatory region and the structural gene, nrfA, for cytochrome c552 of Escherichia coli K-12 have been reported . We have now established that nrfA is the first gene in a seven-gene operon, designated the nrf operon, at least five of which are essential for formate-dependent nitrite reduction to ammonia . This operon terminates just upstream of the previously sequenced gltP gene encoding a sodium-independent, glutamate and aspartate transporter . Expression of lac fused to nrfA, nrfE or nrfG is regulated by oxygen repression, FNR-dependent anaerobic induction, nitrite induction and nitrate repression during anaerobic growth, exactly as previously reported for the nrfA promoter . In contrast, expression of the gltP-lac fusion was FNR-independent . The open reading frame immediately downstream of nrfA encodes NrfB, a hydrophilic, penta-haem cytochrome c with an M(r) of 20,714 . The structure of the N-terminal region is typical of a signal peptide for a periplasmic protein: cleavage at the putative signal peptide cleavage site, Ala-26, would result in a periplasmic cytochrome with a molecular mass of 18 kDa . The NrfC polypeptide, M(r) 24,567, contains 16 cysteine residues arranged in four clusters typical of the CooF super-family of non-haem iron-sulphur proteins . The NrfD sequence predicts a 318-residue hydrophobic protein with a distribution of acidic and basic amino acids which suggests that NrfD is an integral transmembrane protein with loops in both the periplasm and the cytoplasm . Proteins most similar to NrfD include the PsrC subunit of polysulphide reductase from Wolinella, but, as seven of the 10 most similar proteins are NADH-ubiquinone oxidoreductases, we propose that NrfD participates in the transfer of electrons from the quinone pool into the terminal components of the Nrf pathway . NrfE, M(r) 60,851, is predicted to be another hydrophobic, integral membrane protein homologous to the CdI1 protein of Rhodobacter capsulatus, which has been implicated in the assembly of periplasmic c-type cytochromes . The sequence of the 127 residue NrfF polypeptide, M(r) 14,522, is strikingly similar to the CcI2 protein of R . capsulatus, especially in the putative haem-binding motif, RCPQCQNQN.(ABSTRACT TRUNCATED AT 400 WORDS)

Mol Microbiol, 1994 Apr, 12(1), 1 - 9
Cytochrome c biogenesis in bacteria: a possible pathway begins to emerge; Thony-Meyer L et al.; Cytochrome c biogenesis describes the posttranslational pathway for the conversion of pre-apocytochrome c into the mature holocytochrome c . It involves an unknown number of consecutive biochemical steps, including translocation of the precursor polypeptide and haem into the periplasm and the covalent linkage between these two molecules . Genetic and molecular analysis of several bacterial mutants suggest that at least eight genes contribute to this process . In this review we summarize the present knowledge of the cytochrome c maturation pathway in bacteria and propose a model in which certain genes and their products are attributed to specific functions.

Microsc Res Tech, 1994 Apr 1, 27(5), 389 - 401
Electron microscopic studies of magnetosomes in magnetotactic bacteria; Bazylinski DA et al.; Electron microscopic studies on magnetosomes in magnetotactic bacteria have revealed much information on their composition, structure, and even the formation of their mineral phase . The mineral phases of the magnetosomes are of two general types: iron oxides and iron sulfides . Iron oxide-type magnetosomes contain particles of the ferrimagnetic mineral magnetite (Fe3O4) while the iron sulfide-type contain ferrimagnetic greigite (Fe3S4), greigite and non-magnetic pyrite (FeS2), or possibly ferrimagnetic pyrrhotite (Fe7S8) . Regardless of their composition, the crystalline particles in magnetosomes have a narrow size range: approximately 35 to 120 nm . Magnetite crystals in this size range are single-magnetic-domains and confer a permanent magnetic dipole moment to the cell . The single-domain size range for greigite is not known but is probably similar to that for magnetite . The morphology of the particles in the bacterial magnetosomes appears to be species-specific . Morphologies of magnetite crystals in different species of magnetotactic bacteria include cubo-octahedra, parallelepipedal (truncated hexahedral or octahedral prisms), and tooth- or bullet-shaped (anisotropic) . Morphologies of greigite particles include cubo-octahedra and rectangular prismatic . The greigite-pyrite particles are generally pleomorphic with no consistent crystalline morphology . A membrane has been shown to surround the particles in some organisms and may be involved in the formation of the crystalline phase while also providing physical constraints on the size and the shape of the crystal . These results clearly indicate that the biomineralization process involved in the bacterial magnetosome, a good example of a self-assembled structure on a nanometer scale, is highly controlled by the organism.

Appl Environ Microbiol, 1994 Apr, 60(4), 1179 - 83
Blood agar to detect virulence factors in tap water heterotrophic bacteria; Payment P et al.; Cytolytic colonies were found in 57% of tap water samples, and up to 6% of samples were found to contain bacteria having three or more virulence factors . The factors evaluated were cytotoxicity, hemolysis, cell adherence, and cell invasiveness . Overall, 17% of the samples contained cytolytic colonies that were adherent and hemolytic . Among the media tested, tryptic soy agar with sheep blood (incubated at 35 degrees C for 48 h) was the best medium for the detection of cytolytic colonies . Of the colonies growing on this medium, 13% were cytolytic, whereas on medium R2A, less than 3% were cytolytic . Furthermore, when tryptic soy agar with blood was used, 24% of the samples contained colonies with at least three virulence factors whereas only 5% were positive with R2A . Routine monitoring by using tryptic soy agar with sheep blood is suggested as an appropriate procedure for the detection of bacteria with pathogenic potential in drinking water.

Rev Argent Microbiol, 1994 Apr-Jun, 26(2), 59 - 64
Relationship of physical factors and salinity with indicator bacteria in Bahía Blanca estuary waters, Argentina; Cabezali CB et al.; The relationship between the number of Escherichia coli, terrestrial and marine heterotrophic bacteria, with certain physical and chemical parameters in Bahia Blanca estuary waters, were investigated by means of a statistical analysis of multiple linear regression . The samples were taken during a period of 16 months . Although distance from the sewage outlet seems to be the factor having the greatest effect on the number of alien bacteria, the models obtained for E . coli are inappropriate to predict bacterial behaviour in this particular natural habitat, while for heterotrophic bacteria descriptive models were selected . The results of this study suggest that many factors affect bacterial population densities in this estuarine ecosystem . This should be taken into account trying to solve the problem in order to avoid progressive degradation.

Comput Methods Programs Biomed, 1994 Apr, 42(4), 255 - 62
A simple data compression scheme for binary images of bacteria compared with commonly used image data compression schemes; Wilkinson MH; A run length code compression scheme of extreme simplicity, used for image storage in an automated bacterial morphometry system, is compared with more common compression schemes, such as are used in the tag image file format . These schemes are Lempel-Ziv and Welch (LZW), Macintosh Packbits, and CCITT Group 3 Facsimile 1-dimensional modified Huffman run length code . In a set of 25 images consisting of full microscopic fields of view of bacterial slides, the method gave a 10.3-fold compression: 1.074 times better than LZW . In a second set of images of single areas of interest within each field of view, compression ratios of over 600 were obtained, 12.8 times that of LZW . The drawback of the system is its bad worst case performance . The method could be used in any application requiring storage of binary images of relatively small objects with fairly large spaces in between.

Lett Appl Microbiol, 1994 Apr, 18(4), 214 - 7
Vegetable sponge as a matrix to immobilize micro-organisms: a trial study for hyphal fungi, yeast and bacteria; Iqbal M et al.; The vegetable sponge of Luffa cylindrica was studied as a matrix for the immobilization of hyphal fungi, yeast and bacteria . All were observed to be entrapped within the sponge . When the various immobilized systems were subcultured in their respective fresh nutrient media, the hyphal fungi showed an increase in biomass with no cellular release and secondary colony formation . The immobilized yeast and bacteria released cells into the medium . Advantages of the reticulated biostructure as an immobilization matrix are discussed.

Rev Biol Trop, 1994 Apr-Aug, 42(1-2), 9 - 13
{Isolation of the bacteria Ureaplasma sp . in the reproductive tract of milking cows in Costa Rica}; Leon BA et al.; This is the first report of Ureaplasma sp . from the reproductive tract of Costa Rican cows . Among 204 animals sampled from 11 dairy farms in the country's Central Plateau, the infection rate was 0-71% . Isolation was more frequent in vulvo-vestibular (38.7%) than in cervical swabs (23%) . Ureaplasma was correlated with clinical granular vulvitis symptoms.

Artif Organs, 1994 Mar, 18(3), 188 - 92
Bacteria- and endotoxin-free dialysis fluid for use in chronic hemodialysis; Bambauer R et al.; As the quality of water in the dialysis fluid varies considerably, dialysis fluid is contaminated with a high percentage of bacteria and endotoxins . The bacterial populations contained in the dialysis fluid are as heterogeneous as the chemical structure of the endotoxins that result . The latter can pass through the dialysis membrane whereby high-flux membranes permit a larger number of retransportable molecules than low-flux membranes . A central aim toward a future, safe dialysis process should, therefore, be the production of a dialysate that is free of bacteria and endotoxins . As we were able to demonstrate in various examinations, this goal is most likely to be achieved with the aid of sterile filtration using hollow fiber modules of polyamid . To avoid disinfection of the polyamid membrane, as this would only reach bacteria but not endotoxins, the filter was changed after at most 10 h . The achieved dialysis fluid was free of bacteria and endotoxins . We were also able to show that the release of interleukin-1 was reduced . In addition, side-effects, such as a drop in blood pressure, headaches, muscular cramps, and nausea, were reduced.

Mol Microbiol, 1994 Mar, 11(6), 1151 - 7
Lon-dependent proteolysis of CcdA is the key control for activation of CcdB in plasmid-free segregant bacteria; Van Melderen L et al.; The ccd locus contributes to the stability of plasmid F by post-segregational killing of plasmid-free bacteria . The ccdB gene product is a potent cell-killing protein and its activity is negatively regulated by the CcdA protein . In this paper, we show that the CcdA protein is unstable and that the degradation of CcdA is dependent on the Lon protease . Differences in the stability of the killer CcdB protein and its antidote CcdA are the key to post-segregational killing . Because the half-life of active CcdA protein is shorter than that of active CcdB protein, persistence of the CcdB protein leads to the death of plasmid-free bacterial segregants.

J Cell Sci, 1994 Mar, 107 ( Pt 3), 673 - 82
The distribution of cytoplasmic bacteria in the early Drosophila embryo is mediated by astral microtubules; Callaini G et al.; Maternally inherited cytoplasmic bacteria have occasionally been observed in embryos and adults of different strains of several Drosophila species . While there is a considerable body of data on the relationship between bacteria and embryo viability, little is known about the behavior of these bacteria during the early development of Drosophila . In eggs laid by infected Drosophila melanogaster females we showed that cytoplasmic bacteria were initially concentrated in a thin cortical layer and scattered in the yolk region . During the following syncytial blastoderm mitoses the bacteria mainly accumulated towards the poles of the mitotic spindles, suggesting that astral microtubules play a role in localizing bacteria . This is supported by the observation that treatment of the infected embryos with the microtubule-disrupting drug colchicine led to the partial dissociation of the bacteria from the spindle poles, whereas cytochalasin treatment left almost all the bacterial clusters intact . Moreover, bacteria were not found near the polar bodies and yolk nuclei, which were without astral microtubules . In mitosis-defective embryos, with centrosomes dissociated from the nuclei, the bacteria were concentrated in association with the isolated astral microtubules, and in cold-treated embryos, in which microtubules regrew from isolated centrosomes after recovering, the bacteria clustered around the newly formed asters . These observations, also supported by electron microscope analysis, indicate a close relationship between cytoplasmic bacteria and astral microtubules, and suggest that the latter were able to build discrete cytoplasmic domains ensuring the proper distribution of cytoplasmic components during the blastoderm mitoses, despite the lack of cell membranes.

J Androl, 1994 Mar-Apr, 15(2), 151 - 6
Spermagglutination by bacteria: receptor-specific interactions; Monga M et al.; The influence of genital infection on infertility has yet to be elucidated . We examined receptor-ligand interactions between sperm and Escherichia coli from patients with prostatitis . Two E . coli surface adhesins (P-fimbriae, type 1 fimbriae) and their specific receptor saccharides (alpha-galp-1-4-beta-galp-O-methyl {gal-gal}, mannose) were evaluated . Bacterial concentrations of 10(4) caused spermagglutination . P-fimbriae caused tail-tail spermagglutination that was inhibited by gal-gal . D-mannose concentrations are highest in the acrosomal region and type 1 fimbriae caused head-head agglutination that was inhibited by mannose . Strains with both fimbriae caused head-head and tail-tail agglutination that was inhibited by a mannose/gal-gal combination . E . coli agglutinated 40-75% of motile sperm . Seminal fluid provided 50-100% protection, with lower effectiveness against type 1 fimbriae . Understanding bacteria-spermatozoa interactions at the receptor-ligand level holds potential for treatment of infertility and development of spermagglutinating contraceptives.

Virus Res, 1994 Mar, 31(3), 291 - 303
Expression of the non-structural protein NS1 of bluetongue virus in bacteria and yeast: identification of two antigenic sites at the amino terminus; Gould AR et al.; cDNA transcribed from bluetongue virus serotype 1 (Australia) dsRNA 5 coding for non-structural protein NS1 was amplified in a polymerase chain reaction and ligated downstream of the T7 RNA polymerase promoter in the bacterial expression plasmid pET-5b, as a fusion protein with glutathione S-transferase using the pGEX bacterial expression system or the metallothionein promoter in the yeast expression plasmid pYELC5 . The linear epitopes bound by six monoclonal antibodies to NS1 were localised to two antigenic regions at the amino terminus by Western blots using a series of carboxy-terminal truncations of the NS1 protein overexpressed in Escherichia coli . Expression of truncated NS1 genes using the pGEX expression system in E . coli enabled a more detailed map of the two epitopes to be constructed . The first epitope is thought to lie between amino acid residues 40-59, while the second is defined by the peptide sequences flanking amino acid 96.

Microbiology, 1994 Feb, 140 ( Pt 2), 255 - 61
Isolation and characterization of Bordetella parapertussis-like bacteria from ovine lungs; Porter JF et al.; Bacteria resembling two Bordetella species were isolated from both normal and pneumonic ovine lungs using a selective charcoal agar . Twenty-eight of the 33 isolates showed similarities to stock NCTC B . parapertussis strains in their SDS-PAGE gel protein profiles, in their biochemical reactions and in causing browning on tyrosine agar . Five isolates behaved similarly to stock B . bronchiseptica strains, in being actively motile, in giving identical positive reactions in three out of four biochemical tests and in causing no colour change in tyrosine agar . Multilocus enzyme electrophoresis separated the isolates into two electrophoretic types distinguishable from those of stock B . parapertussis and stock B . bronchiseptica strains.

J Endod, 1994 Feb, 20(2), 75 - 7
Relationship between clinical symptoms and enzyme-producing bacteria isolated from infected root canals; Hashioka K et al.; The object of this study was to determine the correlation between clinical symptoms and the activity of enzymes such as collagenase, chondroitinase, and hyaluronidase produced by bacteria isolated from infected root canals . The materials examined consisted of 28 teeth with apical periodontitis from 25 patients . Bacteria producing collagenase or chondroitinase and hyaluronidase were found to be significantly related to subacute clinical symptoms involving percussion pain . The frequency of bacteria producing collagenase was higher in isolates from root canals with a radiolucent area over 5 mm in diameter than in those from canals having a radiolucent area less than 5 mm in diameter.

Appl Environ Microbiol, 1994 Feb, 60(2), 626 - 36
Phylogenetic analysis and development of probes for differentiating methylotrophic bacteria; Brusseau GA et al.; Fifteen small-subunit rRNAs from methylotrophic bacteria have been sequenced . Comparisons of these sequences with 22 previously published sequences further defined the phylogenetic relationships among these bacteria and illustrated the agreement between phylogeny and physiological characteristics of the bacteria . Phylogenetic trees were constructed with 16S rRNA sequences from methylotrophic bacteria and representative organisms from subdivisions within the class Proteobacteria on the basis of sequence similarities by using a weighted least-mean-square difference method . The methylotrophs have been separated into coherent clusters in which bacteria shared physiological characteristics . The clusters distinguished bacteria which used either the ribulose monophosphate or serine pathway for carbon assimilation . In addition, methanotrophs and methylotrophs which do not utilize methane were found to form distinct clusters within these groups . Five new deoxyoligonucleotide probes were designed, synthesized, labelled with digoxigenin-11-ddUTP, and tested for the ability to hybridize to RNA extracted from the bacteria represented in the unique clusters and for the ability to detect RNAs purified from soils enriched for methanotrophs by exposure to a methane-air atmosphere for one month . The 16S rRNA purified from soil hybridized to the probe which was complementary to sequences present in 16S rRNA from serine pathway methanotrophs and hybridized to a lesser extent with a probe complementary to sequences in 16S rRNAs of ribulose monophosphate pathway methanotrophs . The nonradioactive detection system used performed reliably at amounts of RNA from pure cultures as small as 10 ng.

J Bacteriol, 1994 Jan, 176(1), 44 - 9
GTPase-dependent signaling in bacteria: characterization of a membrane-binding site for era in Escherichia coli; Lin YP et al.; Era is an Escherichia coli GTPase that is essential for cell viability and is peripherally associated with the cytoplasmic membrane . Both immunoelectron microscopy and subcellular-fractionation experiments have shown that Era is present in cytoplasmic as well as membrane-associated pools . These data led to speculation that the mechanism of action of Era may require cycling between membrane and cytoplasmic sites . In order to investigate this possibility, an in vitro binding assay was developed to characterize the binding of Era to membrane fractions . Competition and saturation binding experiments suggest that a site that is specific for Era and capable of binding up to 5 ng of Era per microgram of membrane protein is present in membrane preparations . The binding curve is complex, indicating that multiple equilibria describe the interaction . The binding of Era to this putative receptor is dependent on guanine nucleotides; binding cannot be measured in the absence of nucleotide, and neither ATP nor UTP can substitute . Subfractionation of cell walls showed that the guanine nucleotide-dependent binding site was present in fractions enriched in cytoplasmic membrane . These data provide evidence that Era may be involved in a GTPase-receptor-coupled membrane-signaling pathway that is essential for growth in E . coli.

Adv Biochem Eng Biotechnol, 1994, 51, 71 - 89
Convective drying of bacteria . II . Factors influencing survival; Lievense LC et al.; In the previous part of this review, the parameters of the drying process that can be important for the survival of bacteria upon drying, were reviewed . In this part the other factors which can be important for survival, will be discussed . The discussion starts with the mechanisms that can be responsible for thermal and dehydration inactivation . Moreover, the influence of storage conditions on the stability of dried bacterial cultures will be reviewed.

Int J Syst Bacteriol, 1994 Jan, 44(1), 167 - 71
Assignment of human-derived CDC group 1 coryneform bacteria and CDC group 1-like coryneform bacteria to the genus Actinomyces as Actinomyces neuii subsp . neuii sp . nov., subsp . nov., and Actinomyces neuii subsp . anitratus subsp . nov; Funke G et al.; Almost the entire 16S rRNA gene sequences of some strains of CDC group 1 and group 1-like coryneform bacteria, isolated from human sources, were determined . Comparative analysis of the rRNA sequence data revealed that both groups of coryneforms belong to the genus Actinomyces . On the basis of the present molecular findings and previous biochemical studies, we propose a new Actinomyces species, Actinomyces neuii sp . nov., containing Actinomyces neuii subsp . neuii subsp . nov . for CDC group 1 coryneform bacteria and Actinomyces neuii subsp . anitratus subsp . nov . for CDC group 1-like coryneform bacteria.

Curr Opin Periodontol . 1994;:28-38.
Modulation of immune responses to periodontal bacteria; Gemmell E et al.; There is little doubt that the interaction between the host immune mechanisms and putative periodontal bacteria is fundamental in the clinical manifestations of the different forms of adult chronic inflammatory periodontal disease . Recent work regarding the function of polymorphonuclear neutrophils indicates that, in addition to their established protective and destructive roles, these cells may have a regulatory function in periodontal disease . Equally, emerging evidence suggests that T-cell responses in adult periodontal disease are antigen specific . Further, the migration and retention of specific T cells in the periodontal tissues appears to be related not to the expression of adhesion molecules but rather to the presence of a specific antigen . T-cell subsets are now characterized on the basis of their cytokine profiles . Type 1 T cells produce interleukin-2 and interferon-gamma, whereas type 2 T cells produce interleukin-4 and interleukin-10 . A hypothesis based on this characterization of T cells is presented . According to this hypothesis, susceptible subjects have a type 2 response, whereas nonsusceptible subjects respond predominantly with type 1 T cells . The possible role of interleukin-12 in controlling this response is highlighted, thus demonstrating the marriage of innate and adaptive immune responses in adult periodontal disease.

J Clin Dent, 1994, 4(4), 114 - 9
Relationship between volatile sulfur compounds, BANA-hydrolyzing bacteria and gingival health in patients with and without complaints of oral malodor; De Boever EH et al.; The aim of this study was to obtain measurements of oral malodor, as measured by volatile sulfur compounds (VSC), in periodontally healthy individuals without any complaints of bad breath, and to compare the results with data obtained from patients with complaints of oral malodor . The quality of the mouth air was assessed organoleptically and a portable sulfide monitor was used to measure the concentration of VSC in mouth air . The gingival health of 35 individuals (21 M, 14 F; ages 18-57 years) without any malodor complaints was evaluated according to the Papillary Bleeding Score (PBS) . Pocket depths and Bleeding upon Probing (BOP) were also recorded in 20 patients (11 females and 9 males ranging in age from 14 to 71 years) who complained of oral malodor . Scrapings of the dorsal surface of the tongue and each of 6 plaque samples per patient were evaluated for the presence of BANA-positive species, such as T . denticola, P . gingivalis, and B . forsythus . The organoleptic ratings and VSC values were significantly higher in the complaint group (p < 0.05) . Subjects in the complaint group had a significantly higher percentage of bleeding sites (p < 0.005) and had significantly more plaques that tested positive for the presence of BANA-hydrolyzing species (p < 0.05) . Tongue scrapings of subjects with a high organoleptic score consistently yielded a positive BANA reaction suggesting that the dorsal surface of the tongue is an important niche for BANA-positive, VSC-producing bacteria . This study suggests that the primary sources of VSC production are BANA-hydrolyzing bacteria in the plaque and on the dorsal surface of the tongue.

Microbiol Immunol, 1994, 38(4), 287 - 93
Detection of antibody-coated bacteria in expectorated sputum for diagnosis of lower respiratory infections; Matsumoto T et al.; We evaluated antibody-coated bacteria (ACB) in expectorated sputum to discriminate contaminating or colonizing organisms from true pathogens . We examined 60 expectorated sputum samples from 51 patients with lower respiratory infections (chronic obstructive pulmonary disease 25, pneumonia 20, purulent tracheobronchitis 6) . All samples were examined with quantitative culture and immunofluorescent demonstration of ACB . From the results of quantitative culture, we divided specimens into pathogen-isolated and pathogen-free samples . Among pathogen-isolated samples, in which we isolated accepted pathogenic organisms at > or = 10(7) colony-forming units per ml, 16 of 23 samples were ACB-positive (69.5%) . In contrast, among pathogen-free samples, in which we isolated accepted pathogens at < 10(7) colony forming units per ml or only upper respiratory flora, only 3 of 37 samples were ACB-positive (8.1%) . The ACB-positive rate was significantly higher in pathogen-isolated than in pathogen-free samples (P < 0.001) . Consequently, detecting ACB in expectorated sputum shows good potential as another criterion for distinguishing contaminating or colonizing organisms from true pathogens.

Can J Microbiol, 1994 Jan, 40(1), 67 - 71
Molecular analysis of archael flagellins: similarity to the type IV pilin-transport superfamily widespread in bacteria; Faguy DM et al.; Ultrastructural, biochemical and genetic evidence has shown that the flagella and flagellin proteins from members of the archaea are distinct from their bacterial counterparts . The most important evidence is the sequence dissimilarity between archael and bacterial flagellins . We report here similarity between archael flagellins and members of the bacterial type IV pilin-transport superfamily . In addition to sequence similarity, the archael flagellins and the type IV pilin-transport superfamily share an unusual signal sequence cleavage site and may have functional parallels . This relationship has important implications for the assembly and biogenesis of archael flagella.

Biochimie, 1994, 76(7), 655 - 65
Localization and specificity of cytochromes and other electron transfer proteins from sulfate-reducing bacteria; Le Gall J et al.; Recently data have accumulated concerning the electron transfer chains of sulfate-reducing bacteria in general and of the genus Desulfovibrio in particular . Because of the ever growing number of newly discovered individual redox proteins, it has become essential to try to assign them to physiologically relevant chains . This work presents some new data concerning the localization of these proteins within the bacterial cell and the specificity of electron transfer between the three types of hydrogenases which have been found so far in Desulfovibrio, namely the iron-only, the iron-nickel and the iron-nickel-selenium enzymes . The iron-only hydrogenase reduces cytochromes which have bis-histidinyl heme ligation or histidinyl-methionyl heme ligation . In contrast, the iron-nickel and iron-nickel-selenium hydrogenases cannot reduce cytochromes having a His-Met heme ligation, but are very active toward the cytochromes having a bis-histidinyl ligand . This observation has been used to demonstrate that the tetraheme cytochrome c3 can exchange electrons with the monoheme cytochrome c553 . No clear specificity has been established for the reaction of hydrogenases toward the hexadecaheme cytochromes from either D vulgaris or D gigas.

Biochimie, 1994, 76(6), 569 - 79
Interaction between cytochrome c and the photosynthetic reaction center of purple bacteria: behaviour at low temperature; Mathis P et al.; In purple photosynthetic bacteria the electron donor to the special pair, after its oxidation by a light-induced reaction, is a c-type cytochrome: either a soluble monoheme cytochrome which forms a transitory complex with the reaction center, or a tetraheme cytochrome which remains permanently bound to the reaction center . The effects of low temperatures on electron transfer in the complex are presented and discussed . They provide estimates for the reorganization energy . The most prominent effect of low temperature is that a dominant fast phase of electron transfer becomes impossible at a temperature of around 250 K (monoheme cytochrome) or located between 250 K and 80 K according to the redox state (tetraheme cytochrome) . This inhibition is attributed to a freezing-like transition of pools of water molecules which blocks structural changes of the protein which are normally associated with the cytochrome oxidation.

Ciba Found Symp, 1994, 180, 228 - 38; discussion 238-46
Haem d1 and other haem cofactors from bacteria; Chang CK; Several bacterial haem prosthetic groups whose structures deviate significantly from the ubiquitous protohaem (Fe-protoporphyrin) have been discovered recently . These newly discovered pigments contain dramatic modifications in their aromatic core and/or side chains . Examples include the dioxoisobacteriochlorin-type haem d1 and the chlorin-type haem d as well as the haem a-like haem o . Total syntheses of these macrocycles have been accomplished . Synthetic haem d1 and its analogues were used in reconstitution studies with nitrite reductase which revealed the importance of the oxo groups and the acrylate side chain for enzymic activity . The structural features of these porphyrinoids immediately suggest some possible, but as yet unproven, biosynthetic pathways.

Annu Rev Microbiol, 1994, 48, 223 - 56
Pathways and mechanisms in the biogenesis of novel deoxysugars by bacteria; Liu HW et al.; Science has long recognized the ubiquitously occurring deoxysugars as a novel and important class of carbohydrate, by virtue of the variety of potent and intriguing biological activities they exhibit . The study of the biosynthesis of these naturally vital molecules at a molecular level has received a great deal of attention in recent years, whether it be the well-established study of deoxyribonucleotide biosynthesis via ribonucleotide reductase or newer areas that include 3,6-dideoxyhexose construction and O antigen variation, as well as the emerging scrutiny of the biosynthesis of deoxysugar ligands of antibiotics and cardiac glycosides . This review attempts to update the various classes of deoxy, dideoxy, trideoxy, branched-chain, and amino sugars with respect to our current knowledge regarding the vast biological activities, genetics of formation, and molecular basis of their biosynthesis . In particular, the primary focus utilizes CDP-ascarylose biosynthesis, currently the best genetically and biochemically characterized dideoxysugar system, as a basis for comparison and postulation . This review helps display the elegant complexities of these essential natural saccharides and speculates upon tomorrow's potential applications.

Antonie Van Leeuwenhoek, 1994, 66(1-3), 151 - 64
Photosynthetic electron transport and anaerobic metabolism in purple non-sulfur phototrophic bacteria; McEwan AG; Purple non-sulfur phototrophic bacteria, exemplified by Rhodobacter capsulatus and Rhodobacter sphaeroides, exhibit a remarkable versatility in their anaerobic metabolism . In these bacteria the photosynthetic apparatus, enzymes involved in CO2 fixation and pathways of anaerobic respiration are all induced upon a reduction in oxygen tension . Recently, there have been significant advances in the understanding of molecular properties of the photosynthetic apparatus and the control of the expression of genes involved in photosynthesis and CO2 fixation . In addition, anaerobic respiratory pathways have been characterised and their interaction with photosynthetic electron transport has been described . This review will survey these advances and will discuss the ways in which photosynthetic electron transport and oxidation-reduction processes are integrated during photoautotrophic and photoheterotrophic growth.

Acta Microbiol Immunol Hung, 1994, 41(3), 273 - 81
Bacteria-host relationships in the bivalve mollusc Loripes lucinalis; Herry A et al.; Loripes lucinalis, a lucinid species found in reduced sediments, contains endosymbiotic bacteria within specialized gill cells which contribute to the bivalve's nutrition . An additional bivalve-bacteria association can be seen in the digestive gland where large inclusion bodies filled with rickettsia- or chlamydia-like organisms are observed in the duct and tubule cells . Despite indications of a possible energy parasitism on the part of these endocellular digestive gland bacteria, the digestive epithelium of the host is not significantly damaged by the infection suggesting that this is a generalized and normal bivalve-bacteria association in adults of this species.

Arch Immunol Ther Exp (Warsz), 1994, 42(2), 101 - 6
The reduced expression of HLA-class II antigens and adhesion molecules on monocyte surface after phagocytosis of bacteria; Baran J et al.; The reduced expression of HLA-class II antigens (DQ and DP) and some intercellular adhesion molecules (CD11b, CD54 and CD58) was found on monocytes after phagocytosis of bacteria (S . aureus, E . coli, P . aeruginosa, S . enteritidis) but not of latex particles . In contrast, the expression of HLA-DR, CD11a and CD18 was not changed in the course of phagocytosis . The observed changes were related to the amount of phagocytosed bacteria but not to their viability or phagocytosis induced physical changes expressed as the reduction of FSC signal during flow cytometry analysis.

FEMS Microbiol Lett, 1993 Dec 15, 114(3), 253 - 7
Membrane fatty acid analysis of Antarctic bacteria; Rotert KR et al.; Randomly selected strains of a bacterial collection of marine sea-ice bacteria from Antarctica were analyzed to obtain a profile of the membrane fatty acids . Results showed that short chain saturated and unsaturated fatty acids were more common in the psychrotrophs when compared to psychrophiles . In contrast, branched-chain fatty acids were more abundant in the psychrophiles.

J Virol Methods, 1993 Dec 15, 45(2), 179 - 88
The use of African horse sickness virus VP7 antigen, synthesised in bacteria, and anti-VP7 monoclonal antibodies in a competitive ELISA; Wade-Evans AM et al.; A full-length cDNA clone of genome segment 7 of African Horse Sickness Virus, serotype 9 (AHSV9) was obtained using the PCR technique . The clone was sequenced and found to be 98.27% homologous to the previously published sequence of the equivalent cDNA clone from AHSV4 at the nucleotide level and to exhibit 99.7% identity at the amino acid level . The cDNA clone was transferred to pGEX-2T (Pharmacia), a bacterial expression vector, such that the reading frame of AHSV9 VP7 was continuous with that of the bacterial glutathione-S-transferase (GST) protein, under the control of the bacterial tac promoter . On induction with IPTG a fusion protein consisting of GST and VP7 was synthesised, which was readily purified on a GST-sepharose column (Pharmacia) . The fusion protein reacted equally well in an indirect ELISA using monoclonal antibodies specific for AHSV9 VP7 or polyclonal guinea pig antisera raised against AHSV9 infectious sub-viral particles . This protein was also shown to be a suitable substitute for virus antigen, prepared from infected BHK cell extracts, in a competitive ELISA . Antibodies titres recorded for AHSV9 positive and negative horse sera were similar in the competitive ELISA using either bacterial AHSV VP7 or BHK extracted virus as the source of antigen, in combination with monoclonal or polyclonal antibodies, respectively, as the detectors.

J Biol Chem, 1993 Dec 5, 268(34), 26018 - 25
Structural and functional characterization of the HPV16 E7 protein expressed in bacteria; Pahel G et al.; The E7 gene of the human papillomaviruses (HPV) encodes a 98-amino acid, multifunctional nuclear phosphoprotein with functional and structural similarities to adenovirus E1A and the papovavirus T antigens . E7 is a viral oncoprotein, which will cooperate with an activated ras oncogene to transform primary rodent cells, and can cooperate with the HPV E6 protein for the efficient immortalization of primary human keratinocytes . Due to the compelling epidemiological and experimental association between HPV infection and cervical cancer, we have undertaken a detailed study of the structure of the HPV16 E7 protein . The E7 protein was expressed in Escherichia coli as a native, unfused polypeptide, and soluble protein was purified by conventional chromatographic techniques . The purified protein was assessed for various biochemical and biophysical properties . Purified E7 binds the retinoblastoma protein avidly and specifically, and it can dissociate the E2F transcription factor when assayed in vitro . Circular dichroism spectroscopy indicated that E7 reversibly binds Zn2+ and Cd2+, resulting in a substantial increase in the alpha-helical content of the metal-bound E7 consistent with the stabilization of a hydrophobic core in the COOH terminus of the protein.

Epidemiol Infect, 1993 Dec, 111(3), 499 - 502
Intracellular growth of Legionella pneumophila serogroup 1 monoclonal antibody type 2 positive and negative bacteria; Edelstein PH et al.; Epidemiological evidence suggests that monoclonal antibody type 2 positive (MAB 2+) Legionella pneumophila serogroup 1 (LP1) more often causes disease than do MAB 2- isolates, and there is evidence that MAB 2- LP1 grow less well in cells than do MAB 2+ bacteria . We tested the intracellular growth rates of ten randomly selected MAB 2- LP1 isolates, by using guinea-pig alveolar macrophages, and human monocyte-derived macrophages . Save a low virulence control, all ten MAB 2- isolates grew as well in cells as a virulent MAB 2+ isolate . Heterogeneity of MAB 2- LP1 growth in cells exists, making poor intracellular growth an unlikely explanation for why MAB 2+ LP1 appear to cause disease more often.

Carcinogenesis, 1993 Dec, 14(12), 2633 - 6
Intestinal bacteria and endogenous production of malonaldehyde and alkylators in mice; Kautiainen A et al.; Association of intestinal bacteria with endogenous production of some reactive compounds was studied by determination of adducts to haemoglobin in blood from germ-free and corresponding control mice . N-terminal valines in haemoglobin were analysed with regard to adducts from malonaldehyde (MA), ethene/ethylene oxide, propene/propylene oxide and methylating agents . It was found that the adduct levels from MA were 1.65 and 3.32 nmol/g globin in germ-free and control mice, respectively . The levels of adducts from ethylene oxide and propylene oxide were 10.8 and 10.3 pmol/g globin, respectively, in germ-free and 21.7 and 17.7 pmol/g globin, respectively, in control mice . The level of adducts from endogenous methylating agents was higher in germ-free mice than in controls (473 and 408 pmol/g globin, respectively) . These differences in adduct levels between germ-free and conventional mice are statistically significant . The causes of the observed variations are so far not identified . This study confirms earlier findings on background levels of adducts in unexposed individuals and supports the hypothesis that these adducts reflect the occurrence of reactive intermediates in vivo that may constitute cancer risks in background cancer incidence . The present study also shows that intestinal bacteria may be an important determinant of such endogenous risk factors.

Hua Xi Yi Ke Da Xue Xue Bao, 1993 Dec, 24(4), 392 - 4
{Spiral shaped bacteria in the human gastric biopsy}; Chen Z et al.; Biopsy specimens from the gastric mucosa of 149 patients who underwent gastroduodenal endoscopy for upper gastrointestinal complaints were studied by light microscopy and culture . Spiral shaped bacteria were detected in four of the specimens by smears with Gram stain . The positive rate was 2.68%, but these bacteria and HP did not grow in culture . The characteristic helical morphology of the bacteria appears to be similar to that of the bacteria found in the stomach of cats and dogs . And what of significance in these cases is the presence of spiral shaped bacteria in association with chronic gastritis.

PCR Methods Appl, 1993 Dec, 3(3), 181 - 5
Effect of amplicon size on PCR detection of bacteria exposed to chlorine; McCarty SC et al.; The effect of amplicon size on the PCR detection of Legionella pneumophila after chlorine inactivation was investigated . Two amplicons specific to the L . pneumophila mip gene were used for the PCR analyses: a 650-bp amplicon and smaller 168-bp amplicon within the 650-bp amplicon; a 108-bp amplicon specific to species rRNA coding sequence also was used . After exposure to chlorine, viable agar grown cells were not detected by plate counts or direct counts with p-iodonitrotetrazolium (INT) after 1 min for treatment at 10 mg/l, after 2 min for treatment at 5 mg/l, and after 4 min for treatment at 2.5 mg/l; viable water grown cells were present at least 4 min after biocide addition even with a chlorine dose of 5 mg/l . At the 10-mg/l dosage, PCR products from the 168-bp amplicon were detected on agarose gels up to 16 min after chlorination; even after 24 hr of PCR the 168-bp products were detectable using a capture probe hybridization assay . However, the 650-bp target was not detected after 4 min chlorine contact time at the same biocide dosage using agarose gels, and PCR products could not be detected by hybridization after 32 min . At lower chlorine concentrations, a similar pattern was seen with the 168-bp amplicon detectable longer after biocide addition than the 650-bp mip amplification target . On the basis of these data, larger amplicons appear to correlate better with viability of L . pneumophila in water samples.

Curr Opin Genet Dev, 1993 Dec, 3(6), 849 - 54
The accessory genetic elements of bacteria: existence conditions and (co)evolution; Levin BR; The accessory elements of bacteria, transposons, plasmids and phages provide tillable as well as fertile ground for studying the ecology and (co)evolution of parasite and symbiont interactions with their hosts . The recent climate has yielded a bountiful harvest of delicious evolutionary food for thought.

Nippon Koshu Eisei Zasshi, 1993 Dec, 40(12), 1163 - 8
{Cognitive ability regarding dental plaque and oral bacteria in schoolchildren: results from an interview research of primary and junior high school students}; Watanabe M et al.; The cognitive abilities regarding dental health terms, especially of dental plaque, were examined among schoolchildren . An interview of 112 primary and junior high school students was performed to test knowledge of the cause of dental caries and meaning of some dental health terms . Results indicate that most schoolchildren had difficulty understanding the correct meaning of dental plaque and oral bacteria . Some of them did not recognize the existence of oral bacteria, much less dental plaque . From these results, factors which may interfere with correct understanding of dental plaque were examined . Among them, inaccurate knowledge of existence of oral bacteria appears to be an important factor.

Biull Eksp Biol Med, 1993 Nov, 116(11), 536 - 8
{Changes in the chromatin structure under the influence of intranuclear bacteria with antihistone activity}; Sokolov VIu; Computed TV morphodensitometry was used to examine the integration of bacteria into the human nuclear genome . The bacterial strains with antihistone activity were shown to be incorporated into the structure of chromatin structure of an epithelial cell with its network organization impaired . The microscopic analysis of cultured Hep 2 cells by manual scanning indicated that genetically active bacteria were incorporated into the nucleus and nucleolus.

Poult Sci, 1993 Nov, 72(11), 2152 - 6
An evaluation of a rinse procedure using sodium bicarbonate and hydrogen peroxide on the recovery of bacteria from broiler carcasses; Fletcher DL et al.; A patent entitled "Reduction of Bacteria Count on Poultry Being Processed into Food at a Poultry Processing Plant" (U.S . Patent No . 4,683,618) claimed that a three-step rinse process using sodium bicarbonate and hydrogen peroxide solutions would remove bacteria from the surface of broiler carcasses . In three replicate trials, 40 broilers were obtained postchill from a commercial processing plant . Broilers (n = 20) were treated according to the patent by spraying the inside and outside surfaces of each carcass with a 2% NaHCO3 solution for 5 s and rinsing with water, repeating, spraying with a 3% H2O2 solution for 5 s, and rinsing a final time with water . Controls (n = 20) were treated identically except that in each of the rinse steps tap water was used in place of the test solutions . Whole carcass rinses were conducted and total aerobic plate counts (TPC) and impedance detection times (DT) were determined after 1 h and 7 days at 4 C . The NaHCO3 + H2O2 treatment resulted in no significant difference in TPC at 1 h post-treatment but did result in lower TPC after 7 days and greater DT at both 1 h and 7 days . The procedure was effective in reducing the recovery of bacteria at 7 days post-treatment by .3 log10 but was not effective in removing the bacteria to the extent implied in the patient . Based on previous studies using H2O2, these results are not unexpected, but commercial applicability remains questionable based on actual reduction levels.

Toxicology, 1993 Oct 5, 82(1-3), 21 - 37
Expression of human cytochrome P450 enzymes in yeast and bacteria and relevance to studies on catalytic specificity; Guengerich FP et al.; Heterologous expression systems can be utilized to great advantage in the study of cytochrome P450 (P450) and other enzymes involved in the biotransformation of drugs and other xenobiotics . The list of studies made possible with the technology includes discernment of catalytic specificity, elucidation of structure-activity relationships, and various biophysical measurements . There are advantages and disadvantages to each of the vector systems and choices must be made on the basis of needs . Yeast expression systems were used to establish that different P450 2C enzymes are involved in the hydroxylations of tolbutamide and (S)-mephenytion . P450 3A4 was also expressed in yeast and its very broad catalytic specificity was confirmed . Recently, it has been possible to express P450 3A4 as well as other human and animal P450s in bacteria after slight modification of their 5'-coding sequences.

Proc Natl Acad Sci U S A, 1993 Oct 1, 90(19), 8787 - 91
Phosphorylation-dependent binding of a signal molecule to the flagellar switch of bacteria; Welch M et al.; Regulation of the direction of flagellar rotation is central to the mechanism of bacterial chemotaxis . The transitions between counterclockwise and clockwise rotation are controlled by a "switch complex" composed of three proteins (FliG, FliM, and FliN) and located at the base of the flagellar motor . The mechanism of function of the switch is unknown . Here we demonstrate that the diffusible clockwise-signal molecule, the CheY protein, binds to the switch, that the primary docking site is FliM, that the extent of CheY binding to FliM is dependent upon the phosphorylation level of CheY, and that it is unaffected by the other two switch proteins . This study provides a biochemical demonstration of binding of a signal molecule to the bacterial switch and demonstrates directly that phosphorylation regulates the activity of this molecule.

Eur J Surg, 1993 Oct, 159(10), 531 - 4
Multivariate analysis for predicting the presence of bacteria in bile in patients with acute cholecystitis; Farinon AM et al.; OBJECTIVE: to find out whether the presence of bacteria in bile could be predicted accurately from preoperative data in patients with acute cholecystitis . DESIGN: Prospective open study . SETTING: University hospital . SUBJECTS: 42 patients undergoing cholecystectomy for acute gallstone cholecystitis . MAIN OUTCOME MEASURES: Correlations between 24 preoperative clinical and laboratory variables, and the incidence of pathogenic organism in bile . RESULTS: 4 of the 24 variables tested were of predictive significance . These were external body temperature on admission, percentage of neutrophils, preoperative white blood cell count, and total serum concentration of bilirubin . When these predictive variables were evaluated in the discriminant analysis equation they had a sensitivity of 92% and a specificity of 100% in predicting positive bile culture . CONCLUSION: Multivariate discriminant analysis permits accurate preoperative prediction of bile cultures growing pathogens in patient undergoing cholecystectomy for acute cholecystitis.

Appl Environ Microbiol, 1993 Oct, 59(10), 3360 - 6
Variations in the uptake and metabolism of peptides and amino acids by mixed ruminal bacteria in vitro; Armstead IP et al.; Mixed ruminal bacteria, isolated from sheep (Q and W) fed a concentrate and hay diet, were anaerobically incubated with either 14C-peptides or 14C-amino acids . Experiment 1 showed that uptake of both 14C-labeled substrates was rapid, but the rate for amino acids was twofold greater than for peptides (molecular weight, 1,000 to 200) initially but was similar after 10 min . Experiment 2 demonstrated that metabolism was also rapid; at least 90% of either 14C-labeled substrate was metabolized by 3 min . Of the radioactivity remaining in bacteria, approximately 30% was in the form of 14C-amino acids, but only in leucine, tyrosine, and phenylalanine . Supernatant radioactivity was contained only in tyrosine, phenylalanine, and mostly proline for incubations with 14C-amino acids but in up to 10 amino acids when 14C-peptides were the substrates . Short-term incubations (< 5 min; experiment 3) confirmed previous uptake patterns and showed that the experimental system was responsive to substrate competition . Experiment 4 demonstrated that bacteria from sheep Q possessed initial and maximum rates of 14C-amino acid uptake approximately fourfold greater (P < 0.01) than those of 14C-peptides, but with no significant differences (P > 0.1) between four 14C-peptide substrate groups with molecular weights of 2,000 to < 200 . By contrast, bacteria from sheep W showed no such distinctions (P > 0.1) between rates for 14C-peptides and 14C-amino acids . Calculations suggested that peptides could supply from 11 to 35% and amino acids could supply from 36 to 68% of the N requirements of mixed ruminal bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Appl Environ Microbiol, 1993 Oct, 59(10), 3306 - 13
Mobile bacteria and transport of polynuclear aromatic hydrocarbons in porous media; Jenkins MB et al.; Sorption of hydrophobic pollutants such as polynuclear aromatic hydrocarbons (PAHs) to soil and aquifer materials can severely retard their mobility and the time course of their removal . Because mobile colloids may enhance the mobility of hydrophobic pollutants in porous media and indigenous bacteria are generally colloidal in size, bacterial isolates from soil and subsurface environments were tested for their ability to enhance the transport of phenanthrene, a model PAH, in aquifer sand . Batch isotherm experiments were performed to measure the ability of selected bacteria, including 14 isolates from a manufactured gas plant waste site, to sorb 14C-phenanthrene and to determine whether the presence of the suspended cells would reduce the distribution coefficient (Kd) for phenanthrene with the sand . Column experiments were then used to test the mobility of isolates that reduced the Kd for phenanthrene and to test the most mobile isolate for its ability to enhance the transport of phenanthrene . All of the isolates tested passively sorbed phenanthrene, and most but not all of the isolates reduced the Kd for phenanthrene . Some, but not all, of those isolates were mobile in column experiments . The most mobile isolate significantly enhanced the transport of phenanthrene in aquifer sand, reducing its retardation coefficient by 25% at a cell concentration of approximately 5 x 10(7) ml-1 . The experimental results demonstrated that mobile bacteria may enhance the transport of PAHs in the subsurface.

Appl Environ Microbiol, 1993 Oct, 59(10), 3250 - 4
Effect of monensin on the specific activity of ammonia production by ruminal bacteria and disappearance of amino nitrogen from the rumen; Yang CM et al.; When unadapted mixed ruminal bacteria (312 mg of protein per liter) were treated with monensin (5 mM) in vitro, the rates of ammonia production from enzymatic digests of casein, gelatin, and soy protein (0.5 g of N per liter) were decreased from 46 +/- 2 to 24 +/- 1, 20 +/- 1 to 7 +/- 1, and 40 +/- 2 to 18 +/- 2 nmol/mg of protein per min, respectively . Monensin also caused a decrease in ammonia production in vivo . Nonlactating dairy cows which were fed 0.56 kg of timothy hay 12 times per day had a steady-state ruminal ammonia concentration of 2.7 +/- 0.1 mM, and the ammonia concentration decreased to 1.2 +/- 0.2 mM when monensin (350 mg/day) was added to the diet . The decrease in ammonia production was associated with a 10-fold reduction (4.1 x 10(6) versus 4.2 x 10(5)/ml) in the most probable number of ammonia-producing ruminal bacteria that could use protein hydrolysate as an energy source . Monensin had little effect on the most probable number of carbohydrate-utilizing ruminal bacteria (6.5 versus 7.0 x 10(8)/ml) . The addition of protein hydrolysates (560 g) to the rumen caused a rapid increase in the ammonia concentration, but this increase was at least 30% lower when the animals were fed monensin.(ABSTRACT TRUNCATED AT 250 WORDS)

Anal Biochem, 1993 Oct, 214(1), 149 - 55
In situ determination of the reduction levels of cytochromes b and c in growing bacteria: a case study with N2-fixing Azorhizobium caulinodans; Pronk AF et al.; The determination of the in situ reduction levels of cytochromes b and c in growing bacteria is achieved by coupling a chemostat with a dual wavelength spectrophotometer . Visible light absorption spectra of cytochromes present in bacterial cells actively growing in a chemostat at a specific growth rate of 0.1 h-1 are recorded . This is accomplished by transporting the emitted light from the spectrophotometer via glass fibers to one side of the chemostat vessel and detecting the transmitted light via a photomultiplier at the other side . The vessel itself is enclosed in a dark box, which contains mirrors on the inside surfaces . The reduction levels of cytochromes b and c during steady state in chemostat cultures are expressed as percentage absorbance of fully reduced cytochromes in the alpha-region of the spectrum . Steady state spectra are recorded in N2-fixing, succinate-limited continuous cultures of Azorhizobium caulinodans at dissolved oxygen tensions in the range between 0.1 and 3.5% O2 . Spectra of fully reduced cytochromes are obtained on the basis of spectra recorded after having reached anoxic conditions by sparging pure nitrogen gas through the culture . These spectra of cytochromes b and c reduced by endogenous substrates are corrected as to give the spectrum of fully reduced cytochromes . The respective contributions of cytochromes b and c to spectra in the alpha-region are estimated by deconvolution using best-fit analysis . Using this in situ technique it is observed that at each dissolved oxygen tension the reduction level of the cytochromes b is higher than that of the cytochromes c.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral Microbiol Immunol, 1993 Oct, 8(5), 277 - 82
Fimbria damage and removal of adherent bacteria after exposure to acoustic energy; McInnes C et al.; The physical effects of low-frequency acoustic energy on Actinomyces viscosus were studied with electron microscopy to explore both acoustically induced damage to fimbriae on the surface of these bacteria and acoustic removal of bacteria from saliva-treated hydroxyapatite disks . A bacterial suspension was exposed to acoustic energy from a laboratory acoustic generator (50 kPa, 200 Hz) and from a new electronic toothbrush, the Sonicare . The exposed bacteria were examined with electron microscopy after negative staining . A decrease in both the percentage of bacterial surface covered with fimbriae and the fimbria length was observed after acoustic exposure . To study the acoustic effects on adherent bacteria, A . viscosus bound to hydroxyapatite disks were exposed to acoustic energy and examined with scanning electron microscopy . Quantitative evaluation of the micrographs for the number of bacteria present after exposure revealed that acoustic energy removed both bacteria adherent to the hydroxyapatite surface and adherent to each other . The results support the concept that an electronic toothbrush employing low-frequency acoustic energy may help prevent and control periodontal diseases by altering bacterial adherence.

FEMS Microbiol Lett, 1993 Sep 15, 112(3), 287 - 90
Instability of waves formed by motile bacteria; Medvinsky AB et al.; Many motile chemotactic bacteria (for instance, Escherichia coli) inoculated at some point in a semisolid nutrient medium can form circular expanding population waves . The formation of these motile structures is due to chemotaxis . The circular waves originate from an expanding bacterial lawn (a parent population) . The regular shape of these waves results from the isotropic distribution of freely diffusible nutrient molecules which are also attractants . In this paper we show that the regular shape of the bacterial population waves can be spontaneously disturbed . As this takes place arc-shaped population waves ('bursts') are formed . It was found that initially the mean length of the cells forming the bursts was greater than that of the parent cell population . But then it decreased resulting in a value characteristic of the parent population.

FEBS Lett, 1993 Sep 6, 330(1), 5 - 7
Excitonic interactions in the light-harvesting antenna of photosynthetic purple bacteria and their influence on picosecond absorbance difference spectra; Novoderezhkin VI et al.; A new model of the light-harvesting antenna (core complex) of purple photosynthetic bacteria is proposed based on excitonic interactions in circular aggregates of bacteriochlorophyll molecules . The calculated absorbance difference spectra of circular aggregates demonstrate all special features observed in the experimental spectra of purple bacteria . In particular, the absorption changes with high amplitude of bleaching at the long-wavelength side of the absorption band at different excitation energy are predicted.

Mol Biol Evol, 1993 Sep, 10(5), 1048 - 59
Positive selection for colicin diversity in bacteria; Riley MA; To examine the hypothesis that colicin proteins are subject to diversity-enhancing selection, we studied the rates of synonymous, nonsynonymous, and intergenic nucleotide substitution in three pairs of closely related colicin clusters . The results indicate that the immunity gene and the immunity-binding domain of the colicin gene, which interact to provide specific immunity from the lethal action of the colicin toxin, accumulate substitutions at synonymous and nonsynonymous sites several times more rapidly than does the remainder of the colicin cluster . We suggest that this increased level of divergence, centered at the immunity protein, may be the result of the combined action of recombination and positive selection acting to increase colicin diversity in natural populations of Escherichia coli.

J Bone Joint Surg Br, 1993 Sep, 75(5), 724 - 30
Effect of antiseptics, ultraviolet light and lavage on airborne bacteria in a model wound; Taylor GJ et al.; We modelled a 'clean' surgical wound lightly contaminated with airborne bacteria, using agar, ovine muscle and ovine adipose tissue . This was used to assess the effect on bacteria of ultraviolet C light (UVC) 1200 mu W/cm2, hydrogen peroxide 3%, povidone-iodine 1% and 10%, chlorhexidine 0.05%, pulsed jet lavage with UVC and syringe and needle lavage with chlorhexidine 0.05% . All the agents were effective on agar, but mixing with blood or plasma neutralised hydrogen peroxide and povidone-iodine 1% . All the agents were less effective on tissue specimens than on agar, but were more effective on adipose tissue than on muscle . All the antiseptics except chlorhexidine were less effective when blood or plasma was added to muscle specimens before disinfection . UVC after pulsed jet lavage had an additive effect . Syringe and needle lavage with chlorhexidine 0.05% was the most effective method tested; it reduced colony counts by 99.8% and warrants clinical investigation.

Microbiol Rev, 1993 Sep, 57(3), 655 - 82
Genetics of lipopolysaccharide biosynthesis in enteric bacteria; Schnaitman CA et al.; From a historical perspective, the study of both the biochemistry and the genetics of lipopolysaccharide (LPS) synthesis began with the enteric bacteria . These organisms have again come to the forefront as the blocks of genes involved in LPS synthesis have been sequenced and analyzed . A number of new and unanticipated genes were found in these clusters, indicating a complexity of the biochemical pathways which was not predicted from the older studies . One of the most dramatic areas of LPS research has been the elucidation of the lipid A biosynthetic pathway . Four of the genes in this pathway have now been identified and sequenced, and three of them are located in a complex operon which also contains genes involved in DNA and phospholipid synthesis . The rfa gene cluster, which contains many of the genes for LPS core synthesis, includes at least 17 genes . One of the remarkable findings in this cluster is a group of several genes which appear to be involved in the synthesis of alternate rough core species which are modified so that they cannot be acceptors for O-specific polysaccharides . The rfb gene clusters which encode O-antigen synthesis have been sequenced from a number of serotypes and exhibit the genetic polymorphism anticipated on the basis of the chemical complexity of the O antigens . These clusters appear to have originated by the exchange of blocks of genes among ancestral organisms . Among the large number of LPS genes which have now been sequenced from these rfa and rfb clusters, there are none which encode proteins that appear to be secreted across the cytoplasmic membrane and surprisingly few which encode integral membrane proteins or proteins with extensive hydrophobic domains . These data, together with sequence comparison and complementation experiments across strain and species lines, suggest that the LPS biosynthetic enzymes may be organized into clusters on the inner surface of the cytoplasmic membrane which are organized around a few key membrane proteins.

Endod Dent Traumatol, 1993 Aug, 9(4), 127 - 52
Resin restorations: leakage, bacteria, pulp; Qvist V; Through the development of composite resin materials, the acid-etch technique and dentin adhesives, dentists can now complete perfect and permanent dental restorations--restorations with a color and shape approximating the natural tooth, with perfect marginal adaptation, and no harmful effects to the surrounding tissues, including the dental pulp . However, newer cross-sectional studies indicate that marginal defects are still the main cause of replacement of resin restorations, and that their clinical durability is shorter than that of other types . Moreover, there is no doubt that gap preventive treatments can intensify pulpal reactions to resin restorations if bacterial leakage occurs . The present thesis is based on nine previously published studies (I-IX) . The aims of the studies were: to examine the possibilities of minimizing the occurrence of bacterial leakage around resin restorations through the use of various gap preventive procedures, to extend our understanding of their mode of action, and to investigate the pulpal reactions associated with restorations with and without bacterial leakage . The results of earlier research are reviewed, as well as the various methods for registration of gap occurrence around restorations . Studies I-IX are described briefly and followed by a discussion of the results, a summary and some concluding remarks.

Protein Eng, 1993 Aug, 6(6), 629 - 35
Predicting the point at which transmembrane helices protrude from the bilayer: a model of the antenna complexes from photosynthetic bacteria; Donnelly D et al.; We describe a method for predicting the point at which a transmembrane helix leaves the bilayer and enters the more polar region of the aqueous exterior . This is achieved by comparing the relative directions of the hydrophobic and internal faces of the transmembrane helices which should be opposite for the regions within the bilayer but equivalent for the regions on the outside . This information provides a strong constraint in the process of modelling membrane proteins . We go on to use the approach to model the monomers of the bacterial light-harvesting antenna complexes . This information is then combined with some preliminary crystallographic data and biochemical results to produce a 3-D model of a tetramer.

Can J Microbiol, 1993 Aug, 39(8), 780 - 6
Digestion of cell-wall monosaccharides of ryegrass and alfalfa hays by the ruminal bacteria Fibrobacter succinogenes and Butyrivibrio fibrisolvens; Miron J et al.; The ruminal bacteria Fibrobacter succinogenes strains S85 and BL2 were grown in monocultures or in coculture with strain D1 of Butyrivibrio fibrisolvens, and the solubilization of ryegrass and alfalfa cell walls (CW) and digestion of CW monosaccharides were measured . Fibrobacter succinogenes monocultures and cocultures with B . fibrisolvens D1 degraded 58-69% of ryegrass CW, solubilizing 67-78% of CW glucose, 65-71% of CW xylose, 69-75% of hemicellulose, and 68-77% of total CW monosaccharides . When grown on alfalfa CW, those cultures degraded 28-39% of alfalfa CW, solubilizing 42-58% of CW glucose, 30-36% of CW xylose, and 37-45% of hemicellulose . With respect to both substrates, F . succinogenes strains solubilized CW carbohydrates better than did B . fibrisolvens D1 . Complementary interaction between B . fibrisolvens D1 and the F . succinogenes strains was identified with respect to the utilization of some solubilized carbohydrates, but not with respect to the extent of CW solubilization, which was determined mainly by the F . succinogenes strains . For both substrates, utilization of cellulose by F . succinogenes monocultures was high (96-98%), whereas that of hemicellulose was lower (24-26% in ryegrass and 49-50% in alfalfa) . Under scanning electron microscopy, F . succinogenes bacterial cells attached to and colonized on CW particles were characterized by the appearance of protuberant surface structures that we have identified as "polycellulosome complexes."

Planta Med, 1993 Aug, 59(4), 347 - 50
Metabolism of strychnine N-oxide and brucine N-oxide by human intestinal bacteria; el-Mekkawy S et al.; Anaerobic incubation of strychnine N-oxide with human intestinal bacteria resulted in its transformation to strychnine and 16-hydroxystrychnine . Similarly, brucine N-oxide was transformed to brucine and 16-hydroxybrucine.

Nature, 1993 Jul 22, 364(6435), 358 - 61
Group II self-splicing introns in bacteria; Ferat JL et al.; Like nuclear premessenger introns, group II self-splicing introns are excised from primary transcripts as branched molecules, containing a 2'-5' phosphodiester bond . For this reason, it is widely believed that the ribozyme (catalytic RNA) core of group II introns, or some evolutionarily related molecule, gave rise to the RNA components of the spliceosomal splicing machinery of the eukaryotic nucleus . One difficulty with this hypothesis has been the restricted distribution of group II introns . Unlike group I self-splicing introns, which interrupt not only organelle primary transcripts, but also some bacterial and nuclear genes, group II introns seemed to be confined to mitochondrial and chloroplast genomes (reviewed in ref . 6) . We now report the discovery of group II introns both in cyanobacteria (the ancestors of chloroplasts) and the gamma subdivision of purple bacteria, or proteobacteria, whose alpha subdivision probably gave rise to mitochondria . At least one of these introns actually self-splices in vitro.

Eur J Biochem, 1993 Jul 15, 215(2), 401 - 10
Calcium binding by chick calretinin and rat calbindin D28k synthesised in bacteria; Cheung WT et al.; Calretinin is a member of the EF-hand calcium-binding protein family, with a high similarity with calbindin D28k . The chick calretinin cDNA sequence was reconstructed in a M13 vector and transferred into an expression plasmid derived from the pET series . The calretinin gene was expressed in Escherichia coli and produced immunoreactive calretinin of the expected size . Bacterially expressed calretinin was purified with successive ammonium-sulfate precipitation, DEAE chromatography, hydroxyapatite chromatography, Sephadex G-75 chromatography and Mono-Q chromatography . Normally, 1.0-1.5 mg calretinin was obtained from 1 l bacterial culture with a protein recovery of 0.5-1.5% . Calbindin D28k was purified similarly from bacteria using an expression plasmid provided by W . Hunziker . Calcium-binding activity of purified proteins was measured by equilibrium dialysis in calcium/EGTA mixtures with 45Ca as tracer . Both calretinin and calbindin D28k bound 3-4 Ca2+/molecule (calretinin, 4.0 +/- 0.5; calbindin D28k, 3.5 +/- 0.4), implying that at least one of the canonical EF-hand domains does not bind calcium . The Kd was 0.3-0.5 microM with little difference between the values for the two proteins.

Biochim Biophys Acta, 1993 Jul 11, 1157(3), 275 - 84
Resonance Raman study of sirohydrochlorin and siroheme in sulfite reductases from sulfate reducing bacteria; Underwood-Lemons T et al.; Soret-excited resonance Raman (RR) spectra are reported for the sirohemes in the oxidized and Cr11(EDTA)-reduced forms of both desulforubidin from D . baculatus (DSR) and the low molecular weight sulfite reductase from D . vulgaris (1SIR) and for sirohydrochlorin in the oxidized form of desulfoviridin from D . gigas (DSV) . Several patterns in the RR spectra of these enzymes can be utilized as signatures for the siroheme/sirohydrochlorin moiety . The active site for DSR and 1SIR consists of a siroheme exchange-coupled to a {4Fe-4S}2+ cluster . Upon addition of Cr11(EDTA), the active center of DSR and 1SIR undergoes a one-electron and two-electron reduction, respectively . The RR spectra of DSR suggest that the siroheme iron is high spin and 5-coordinate in the oxidized enzyme and probably remains high spin and 5-coordinate upon reduction . The iron in the siroheme of oxidized 1SIR changes from a low spin and probably 6-coordinate configuration to a high spin, 5-coordinate complex upon two-electron reduction of the active site . Close similarities between the RR spectral features of the two-electron-reduced assimilatory sulfite reductases from E . coli and from D . vulgaris (1SIR) are discussed.

Int J Syst Bacteriol, 1993 Jul, 43(3), 471 - 3
Molecular taxonomic studies of Actinomyces-like bacteria isolated from purulent lesions in pigs and description of Actinomyces hyovaginalis sp . nov; Collins MD et al.; The 16S rRNA gene sequence of some Actinomyces-like bacteria isolated from purulent lesions in pigs was determined . A comparative analysis of the rRNA sequence data revealed that the bacteria are members of the genus Actinomyces, but are phylogenetically distinct from Actinomyces suis . On the basis of our findings and the results of previous phenotypic studies it is formally proposed that the bacteria from pigs should be designated a new species, Actinomyces hyovaginalis.

Poult Sci, 1993 Jul, 72(7), 1224 - 9
Effects of different floor types and levels of washing of waterers on broiler performance and bacteria count of drinking water; Andrews LD et al.; The objective of the present experiment was to determine the effect of different flooring materials and washing of waterers on broiler performance . The floor treatments were 1) black, plastic-coated expanded metal, relatively rigid (B); 2) white plastic, semi-rigid, with rectangular openings (WR); 3) white plastic, semi-rigid, with square openings (WS); and 4) 3 cm of rice hull litter (C) . One hanging waterer was placed in each pen . Wash treatments were 1) trough and bell washed every Monday, Wednesday, and Friday (AW); 2) wash trough only on Monday, Wednesday, and Friday (TW); and 3) the waterers were never washed after the 2nd wk (NW) . Broilers reared on C has significantly lower BW than those broilers on B floors . Broilers reared on the B and WS floors had significantly higher breast blister scores and percentage of birds with blisters than broilers reared on C floors . Broilers reared on C had lower enlarged feather follicle scores than those reared on all raised floors and a lower percentage of enlarged feather follicles than those broilers reared on WS or WR floors . Broilers reared on WS+TW had significantly better feed conversion than WS+AW, B+TW, and B+AW treatments . Broilers reared on WR+TW treatment were significantly higher in breast blister score than broilers reared on WR+AW, C+TW, and C+AW treatments . Broilers reared on C+TW and C+AW treatments were significantly lower in breast blister score except for broilers reared on C+NW, WR+AW, and WS+AW treatments . Broilers reared on C+NW treatment were significantly lower in enlarged feather follicle score than those broilers reared on B+TW, WR+AW, and WS+NW treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Gene, 1993 Jun 15, 128(1), 111 - 7
A revised strategy for cloning antibody gene fragments in bacteria; Posner B et al.; The ability to clone and overexpress genes encoding mouse Fab (antigen-binding fragment) proteins in bacteria led to the development of a methodology which has the potential to replace traditional hybridoma technology {Huse et al., Science 246 (1989) 1275-1281}; however, several observations have suggested that clones with desirable chemical properties may be missed in immunoscreens of large combinatorial libraries due to low levels of functional Ab protein . To increase the efficiency of cloning and characterization of Ab gene fragments, we have reconsidered several features of the original cloning vehicles . These studies show that at the present time a unique expression system cannot adequately accommodate the requirements of plaque-lift immunoassays for clonal selection and biochemical assays for further characterization in vitro . A monocistronic arrangement of heavy- and light-chain-encoding genes using two lacP promoters produces sufficient amounts of functional Ab protein for clonal selection from phage lambda libraries and minimizes interference with the lytic cycle of recombinant vectors . In liquid culture, a strong coliphage promoter and a relatively abundant RNA polymerase can be used to produce quantities of Ab protein sufficient for further characterization in vitro . A rapid purification protocol obviates the need for fusing heavy-chain protein to a decapeptide sequence, an affinity-tail sequence which slows the folding and assembly of the Ig heterodimer . These results have been used to formulate a new strategy for cloning and characterization of Ab gene fragments in bacteria.

Proc Natl Acad Sci U S A, 1993 Jun 15, 90(12), 5695 - 9
Transovarial inheritance of endosymbiotic bacteria in clams inhabiting deep-sea hydrothermal vents and cold seeps; Cary SC et al.; Vesicomyid clams are conspicuous fauna at many deep-sea hydrothermal-vent and cold-seep habitats . All species examined have specialized gill tissue harboring endosymbiotic bacteria, which are thought to provide the hosts' sole nutritional support . In these species mechanisms of symbiont inheritance are likely to be key elements of dispersal strategies . These mechanisms have remained unresolved because the early life stages are not available for developmental studies . A specific 16S rRNA-directed oligodeoxynucleotide probe (CG1255R) for the vesocomyid endosymbionts was used in a combination of sensitive hybridization techniques to detect and localize the endosymbionts in host germ tissues . Symbiont-specific polymerase chain reaction amplifications, comparative gene sequencing, and restriction fragment length polymorphisms were used to detect and confirm the presence of symbiont target in tissue nucleic acid extracts . Nonradioactive in situ hybridizations were used to resolve the position of the bacterial endosymbionts in host cells . Symbiont 16S rRNA genes were consistently amplified from the ovarial tissue of three species of vesicomyid clams: Calyptogena magnifica, C . phaseoliformis, and C . pacifica . The nucleotide sequences of the genes amplified from ovaries were identical to those from the respective host symbionts . In situ hybridizations to CG1255R labeled with digoxigenin-11-dUTP were performed on ovarial tissue from each of the vesicomyid clams . Detection of hybrids localized the symbionts to follicle cells surrounding the primary oocytes . These results suggest that vesicomyid clams assure successful, host-specific inoculation of all progeny by using a transovarial mechanism of symbiont transmission.

Biochim Biophys Acta, 1993 Jun 11, 1157(2), 209 - 10
On the inactivation of bacteria by singlet oxygen--another view; Parker JG; Midden and Dahl, in a recent paper, have presented important data on the inactivation of bacteria by singlet oxygen . In analyzing the data, use was made of a theory published earlier by the present author . The purpose of this paper is to point out that theory and experiment can be brought into better agreement by assuming that the interaction of singlet oxygen with the bacteria takes place in an essentially lipid environment rather than aqueous.

J Steroid Biochem Mol Biol, 1993 Jun, 45(6), 539 - 48
Expression of 5 alpha-reductase in bacteria as a trp E fusion protein and its use in the production of antibodies for immunocytochemical localization of 5 alpha-reductase; Hiipakka RA et al.; A cDNA encoding a full-length rat 5 alpha-reductase was isolated using female rat liver mRNA and the polymerase chain reaction, and fused to the Escherichia coli trp E gene in a pATH expression vector . The trp E-5 alpha-reductase fusion protein expressed in bacteria and a synthetic oligopeptide corresponding to the C-terminus of rat 5 alpha-reductase were used as antigens to produce rabbit polyclonal antibodies to 5 alpha-reductase . Antibodies to the 5 alpha-reductase portion of the fusion protein and to the peptide were purified by affinity chromatography . Antibodies against the 5 alpha-reductase fusion protein reacted with a single component of rat liver microsomes with M(r) 26,000 on Western blots, consistent with the size of 5 alpha-reductase predicted from its cDNA, and with a M(r) 23,000 component on Western blots of detergent extracts of rat ventral prostate nuclei; other rat ventral prostate cellular fractions (mitochondrial, microsomal, cytosol) bound little or no antibody . Antibody against the synthetic peptide reacted with a M(r) 26,000 component of rat liver microsomes as well as with several components in various cellular fractions of rat ventral prostate . With anti-5 alpha-reductase fusion protein antibodies, specific immunocytochemical staining was observed in the epithelial cell nuclei of the rat ventral prostate, seminal vesicle, epididymis and other accessory sex glands . This nuclear staining was specific, since antibodies from non-immunized rabbits did not give nuclear staining and preincubation of the anti-5 alpha-reductase fusion protein antibodies with the trp E-5 alpha-reductase fusion protein eliminated nuclear staining . Incubation of antibodies with trp E (without the 5 alpha-reductase fusion) had no effect on nuclear staining . Specific staining was not detected in the cytoplasm of these epithelial cells . Little or no specific staining was observed in stromal cells in these rat tissues . Human prostate was also immunocytochemically stained with this antibody . Specific staining was found in both epithelial and stromal cell nuclei.

Biochemistry, 1993 Jun 1, 32(21), 5615 - 21
Unexpected similarities of the B800-850 light-harvesting complex from Rhodospirillum molischianum to the B870 light-harvesting complexes from other purple photosynthetic bacteria; Germeroth L et al.; The B800-850 light-harvesting complex (also called LH2) was isolated from photosynthetic membranes of Rhodospirillum molischianum DSM 119 using molecular sieve and ion-exchange chromatography . Its two bacteriochlorophyll a-binding polypeptides (alpha-subunit and beta-subunit) were purified with a reverse-phase HPLC system . The complete amino acid sequences of both subunits have been determined . The alpha- and beta-subunits consist of 56 and 45 amino acids, respectively, corresponding to molecular weights of 5939 and 5133 . In contrast to the B800-850 complexes from other photosynthetic bacteria, the native B800-850 complex from Rs . molischianum is most likely an octamer of monomers with a stoichiometry of three bacteriochlorophyll a and 1.5 lycopenes per alpha,beta-subunit . Resonance Raman spectra provide evidence for a 5-coordinated Mg2+ in the BChl, and a carotenoid mainly in the all-trans configuration . A comparison between resonance Raman data from different photosynthetic bacteria indicates that the BChl a-binding site of the B800-850 complex from Rs . molischianum is more similar to the B870 complexes (also called LH1) than to the B800-850 complexes of other photosynthetic bacteria . Sequence similarities especially between the beta-subunits of the B800-850 complex of Rs . molischianum and the B870 and B800-850 complexes of other photosynthetic bacteria agree with this result and provide information on the mode of pigment binding in bacterial antenna complexes.

J Virol, 1993 Jun, 67(6), 3630 - 4
Effect of linker insertion mutations in the human immunodeficiency virus type 1 gag gene on activation of viral protease expressed in bacteria; Luban J et al.; We have expressed the human immunodeficiency virus type 1 (HIV-1) protease (PR) in bacteria as a Gag-PR polyprotein (J . Luban and S.P . Goff, J . Virol . 65:3203-3212, 1991) . The protein displays enzymatic activity, cleaving the Gag polyprotein precursor Pr55gag to the expected products . The PR enzyme is only active as a dimer, and we hypothesized that PR activation might be used as an indicator of polyprotein multimerization . We constructed 25 linker insertion mutations throughout gag and assessed the PR activity of mutant Gag-PR polyproteins by the appearance of Gag cleavage products in bacterial lysates . All mutant constructs produced stable protein in bacteria . PR activity of the majority of the Gag-PR mutants was indistinguishable from that of the wild type . Six mutants, one with an insertion in the matrix (MA), four with insertions in the capsid (CA), and one with insertions in the nucleocapsid (NC), globally disrupted polyprotein processing . When PR was provided in trans on a separate plasmid, the Gag proteins were cleaved with wild-type efficiency . These results suggest that the gag mutations identified as disruptive of polyprotein processing did not conceal the scissile bonds of the polyprotein . Rather, the mutations prevented PR activation in the context of a Gag-PR polyprotein, perhaps by preventing polyprotein dimerization.

Zentralbl Bakteriol, 1993 Jun, 279(1), 140 - 5
Isolation and characterization of group EF-4 bacteria from various lesions in cat, dog and badger; Corboz L et al.; Bacteria of Group EF-4 were isolated from local purulent lesions in 7 dogs and in 5 cats, from pneumonic lungs in 2 additional cats and from internal organs in a badger . Results of characterization were compared with those of a human strain of Group EF-4a isolated from an infected dog-bite wound . Lungs of 2 necropsied cats showed a severe focal necrotizing pneumonia in the various lobes . Organs of the badger were typical for a case of septicemia . The organisms were isolated mostly in pure culture . Colonies were up to 1.5 mm in size, round, entire, more or less yellowish pigmented and non hemolytic . Culture smelled slightly like popcorn . In conventional biochemical tests, 12 isolates as well as the human strain were shown to belong to Group EF-4a and the 3 remaining strains to EF-4b . Belonging to Group EF-4 was confirmed by assimilation tests with the gallery ATB 32 GN of BioMerieux . However some differences to other reports were observed when compared with results obtained with similar methods . Results of this study seem to indicate that bacteria of Group EF-4 are important in veterinary medicine not only from an epidemiological but also from an etiological point of view.

Am J Physiol, 1993 Jun, 264(6 Pt 1), E966 - 72
Binding and degradation of 3,5,3'-triiodothyronine and thyroxine by rat intestinal bacteria; DiStefano JJ 3rd et al.; Intestinal bacteria hydrolyze conjugates of thyroxine (T4) and 3,5,3'-triiodothyronine (T3) secreted in bile, but it is not clear whether they have any other role in metabolism, storage, transport, or action of thyroid hormone in the intestines . We have examined aspects of T3 and T4 binding and degradation processes in fresh feces and cecum contents, obtained from normal control rats and from rats partially decontaminated by treatment with oral antibiotics for 2-3 wk . Samples were homogenized in phosphate buffer, fractionated, and subjected to various test conditions and incubated at 37 degrees C with 125I-labeled T3 (T3*) or T4 (T4*) for 2 or 24 h . Supernatants of high-speed centrifuged incubates were chromatographed to test for degradation products, and percentage binding was measured in the pellets . Substantial binding of T3* and T4* was found in all control rat feces and cecum content samples by 2 h, but binding was absent or significantly reduced in partially decontaminated rat samples . Bacterial binding of T3* and T4* were further shown to be competitive with graded doses of bovine serum albumin . Considerable degradation of T3* and T4* to labeled iodide (I*) only was also observed in feces and cecum content samples and was much greater in control rat than in corresponding partially decontaminated rat samples . Light had no effects in our system and heat reduced I* production . Propylthiouracil and sodium ipodate had little effect or equivocal effects, but dithiothreitol substantially inhibited I* production.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral Microbiol Immunol, 1993 Jun, 8(3), 182 - 7
Sensitization of periodontopathogenic bacteria to killing by light from a low-power laser; Wilson M et al.; Cultures of Porphyromonas gingivalis, Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans were treated with a range of photosensitizers and then exposed to light from a 7.3 mW helium/neon laser for up to 80 s . Toluidine blue O (25 micrograms/ml) and methylene blue (25 micrograms/ml) were effective lethal photosensitizers of all 3 target organisms, enabling substantial light dose-related reductions in viable counts . Dihaematoporphyrin ester and aluminium disulphonated phthalocyanine were lethal photosensitizers only of P . gingivalis . In the absence of a photosensitizer, exposure to laser light had no significant effect on the viability of the cultures . If such low doses of light (22 J/cm2) are effective at killing bacteria in vivo, the technique may be useful as a means of eliminating periodontopathogenic bacteria from diseased sites.

Biochemistry, 1993 May 11, 32(18), 4793 - 800
The interaction between cytochrome c2 and the cytochrome bc1 complex in the photosynthetic purple bacteria Rhodobacter capsulatus and Rhodopseudomonas viridis; Guner S et al.; The rates of electron transfer from a ubiquinol analogue to cytochrome c2 catalyzed by the cytochrome bc1 complexes of Rhodobacter capsulatus and Rhodopseudomonas viridis were measured as a function of ionic strength . The effects of ionic strength on the kinetic parameters for the reactions are consistent with a role for electrostatic complex formation between cytochrome c2 and the cytochrome bc1 complex in the electron-transfer pathways in both photosynthetic purple non-sulfur bacteria . Additional support for a docking model in which positively charged lysines on cytochrome c2 interact with negatively charged groups on the Rb . capsulatus cytochrome bc1 complex was obtained from kinetic experiments using Rb . capsulatus cytochrome c2 and equine cytochrome c in which specific lysine residues were altered by site-directed mutagenesis and chemical modification, respectively . Equine cytochrome c, which is a poor electron donor to the reaction center of Rps . viridis, is an effective electron acceptor for the Rps . viridis cytochrome bc1 complex . Chemical modification of lysine residues on Rps . viridis cytochrome c2 has a substantially greater effect on the reduction of the Rps . viridis reaction center by ferrocytochrome c2 than on the oxidation of the Rps . viridis cytochrome bc1 complex by ferricytochrome c2 . These data suggest that the docking site for Rps . viridis cytochrome c2 on the Rps . viridis reaction center tetraheme subunit differs in structure from the docking site for the cytochrome on the Rps . viridis cytochrome bc1 complex to a significant extent . In this respect, Rps . viridis differs from photosynthetic purple non-sulfur bacteria in which the reaction center does not contain a tetraheme subunit, where the binding sites for cytochrome c2 on the reaction center and the cytochrome bc1 complex appear to be quite similar.

FEBS Lett, 1993 Apr 19, 321(1), 6 - 10
Expression of mouse rod photoreceptor cGMP phosphodiesterase gamma subunit in bacteria; Qin N et al.; We expressed the gamma subunit of mouse rod photoreceptor cGMP phosphodiesterase (PDE) in the bacterial pGFX-2TK expression vector which produces a cleavable 40 kDa fusion protein . The fusion protein can be isolated in a one step procedure by affinity chromatography on glutathione beads . The yield of purified fusion protein is approximately 10 mg from 1 liter of bacterial culture, or about 3 mg of PDE gamma equivalent to the PDE gamma content of approximately 200,000 mouse retinas . Both the fusion protein and the cleaved PDE gamma, to which a short kinase domain remains attached, are biologically active, inhibiting activated PDE in a manner comparable to native PDE gamma . Immobilized PDE gamma binds transducin alpha subunit charged with GTP, PDE alpha and beta subunits, and, unexpectedly, arrestin (S-antigen).

Lab Anim, 1993 Apr, 27(2), 141 - 50
Intestinal, segmented, filamentous bacteria in a wide range of vertebrate species; Klaasen HL et al.; Segmented, filamentous bacteria (SFBs) form a group of bacteria with similar morphology and are identified on the basis of their morphology only . The relationships of these organisms are unclear as the application of formal taxonomic criteria is impossible currently due to the lack of an in vitro technique to culture SFBs . The intestine of laboratory animals such as mice, rats, chickens, dogs, cats and pigs is known to harbour SFBs . To see whether this extends to other animal species, intestines from 18 vertebrate species, including man, were examined . SFBs were detected with light microscopy in the cat, dog, rhesus monkey, crab-eating macaque, domestic fowl, South African claw-footed toad, carp, man, laboratory mouse and rat, wood mouse, jackdaw and magpie . These results suggest that non-pathogenic SFBs are ubiquitous in the animal kingdom . Among apparently identical animals, there was considerable variation in the degree of SFB colonization . It is suggested that SFB colonization could serve as a criterion of standardization of laboratory animals.

Eur J Biochem, 1993 Apr 1, 213(1), 81 - 6
Phosphorylation and activation of the arachidonate-mobilizing phospholipase A2 in macrophages in response to bacteria; Svensson U et al.; The role of potential target enzymes in the protein-kinase-C-independent eicosanoid response triggered by certain bacteria in murine peritoneal macrophages {Svensson, U., Holst, E . & Sundler, R . (1991) Eur . J . Biochem . 202, 699-705} has been investigated . The eicosanoid response was found to be due to an increase in the mobilization of arachidonate rather than to inhibition of arachidonate esterification or activation of the cyclooxygenase pathway and to be accompanied by a persistent increase in the activity of the arachidonate-mobilizing phospholipase A2 (PLA2-85) . Also, down-regulation of protein-kinase C by prolonged treatment with 4 beta-phorbol 12-myristate 13-acetate did not reduce the bacterial activation of PLA2-85 . The increase in activity of PLA2-85, like the increase in eicosanoid formation, showed a lag period of approximately 10 min . Furthermore, exposure of 32P-labeled macrophages to either bacteria (Gardnerella vaginalis) or the protein-phosphatase inhibitor okadaic acid caused an increase in the phosphorylation of PLA2-85 . Okadaic acid (0.5 microM), which itself caused arachidonate mobilization and activation of PLA2-85 after a lag period of approximately 45 min, greatly promoted the response to bacteria even at earlier time points . This study provides strong evidence that the eicosanoid response to bacteria in macrophages occurs via a protein-kinase-C-independent activation of PLA2-85 and that this activation is due to an increase in the phosphorylation of the enzyme.

J Bacteriol, 1993 Apr, 175(8), 2414 - 22
bchFNBH bacteriochlorophyll synthesis genes of Rhodobacter capsulatus and identification of the third subunit of light-independent protochlorophyllide reductase in bacteria and plants; Burke DH et al.; We present the nucleotide and deduced amino acid sequences of four contiguous bacteriochlorophyll synthesis genes from Rhodobacter capsulatus . Three of these genes code for enzymes which catalyze reactions common to the chlorophyll synthesis pathway and therefore are likely to be found in plants and cyanobacteria as well . The pigments accumulated in strains with physically mapped transposon insertion mutations are analyzed by absorbance and fluorescence spectroscopy, allowing us to assign the genes as bchF, bchN, bchB, and bchH, in that order . bchF encodes a bacteriochlorophyll alpha-specific enzyme that adds water across the 2-vinyl group . The other three genes are required for portions of the pathway that are shared with chlorophyll synthesis, and they were expected to be common to both pathways . bchN and bchB are required for protochlorophyllide reduction in the dark (along with bchL), a reaction that has been observed in all major groups of photosynthetic organisms except angiosperms, where only the light-dependent reaction has been clearly established . The purple bacterial and plant enzymes show 35% identity between the amino acids coded by bchN and chlN (gidA) and 49% identity between the amino acids coded by bchL and chlL (frxC) . Furthermore, bchB is 33% identical to ORF513 from the Marchantia polymorpha chloroplast . We present arguments in favor of the probable role of ORF513 (chlB) in protochlorophyllide reduction in the dark . The further similarities of all three subunits of protochlorophyllide reductase and the three subunits of chlorin reductase in bacteriochlorophyll synthesis suggest that the two reductase systems are derived from a common ancestor.

J Med Chem, 1993 Mar 19, 36(6), 784 - 9
Structure-activity relationship of glycine betaine analogs on osmotolerance of enteric bacteria; Abdel-Ghany YS et al.; Bacterial cells have the ability to accumulate compatible solutes within the cytoplasm to maintain their osmolarity above that of the extracellular milieu . Glycine betaine (GB) and its biosynthetic precursor choline (Chol) are the major compatible solutes that bacteria accumulate when osmotically challenged . Different osmotically triggered active transport mechanisms have been identified for GB and Chol . In the present study we examined the bioisosteric replacement of the carboxylic group of GB with sulfonic, phosphonic or benzenesulfonamido groups . The sulfonic acid analog (sulfobetaine, compound 3) showed osmoprotectant activity equivalent to that of GB . In addition, we tested the possibility of utilizing GB/Chol transport systems to deliver cytotoxic analogs of GB into three strains of E . coli that differed in their salt resistance . We found that N1-betainyl-N4-(haloacetyl)sulfanilamides (compounds 17c-e) that are GB analogs containing alkylating side chain within their structures inhibited the bacterial growth of the tested standard and salt sensitive strains of E . coli . We also showed that the (N-methyl-cyclic ammonio)methanesulfonates (compounds 21a-c) are able to block Chol transport system in both the standard and the salt-sensitive E . coli strains used . At the concentration used (0.1 mM), none of the tested compounds showed any significant effect on the salt-resistant strain used.

J Exp Zool, 1993 Mar 15, 265(4), 346 - 55
The role of organic osmolytes in osmoregulation: from bacteria to mammals; Kinne RK; Cells of marine species are known to establish osmotic balance with their environment by adjusting the concentrations of organic osmolytes rather than inorganic osmolytes such as sodium, potassium, and chloride . These organic osmolytes fall into three classes: polyhydric alcohols such as sorbitol, amino acids and amino acid derivatives, and urea and trimethylamines . Substantial evidence is available for a central role of each of these classes in osmoregulation in marine species . In this chapter information on the importance of organic osmolytes is extended to a study of isolated mammalian kidney cells . The intracellular concentration of organic osmolytes in these cells responds dramatically to changes in the osmotic environment . The release of sorbitol following hypoosmotic exposure appears to be triggered by calcium, possibly via a mechanism involving membrane recycling . The summarized experiments provide a basis for further work in marine species.

Br Dent J, 1993 Mar 6, 174(5), 167 - 74
Control of bacteria in dental water supplies; Douglas CW et al.; A simple device which releases chlorhexidine acetate into dental unit water supplies is described . The device comprised methyl methacrylate resin containing 40% by weight of chlorhexidine powder, cast into a rod shape and placed in a reservoir . After initial cleaning by flushing with hypochlorite, five dental units were fitted with the device and five units acted as controls . The device successfully kept four units virtually free of bacteria over a 3-month period but effective cleaning of the tubing within the units was found to be essential for success . Sustained release of chlorhexidine offers one means of tackling the problem of contaminated water in dental units, without resorting to complex pumping or metering systems.

Somat Cell Mol Genet, 1993 Mar, 19(2), 193 - 202
Expression of catalytic domains of human UMP synthase in uridine auxotrophic bacteria; Lin T et al.; Orotate phosphoribosyltransferase (OPRT) and orotidine-5'-monophosphate decarboxylase (ODC), which catalyze the last two steps in de novo UMP biosynthesis, are two distinct monofunctional proteins in bacteria and lower eukaryotes . In mammals, OPRT and ODC activities are contained in a single bifunctional protein labeled UMP synthase . The human UMP synthase cDNA was separated into the predicted OPRT and ODC domains using polymerase chain reaction techniques and the domains inserted into pUC19 expression vectors . Following transformation into OPRT- and ODC-deficient E . coli, the strains were able to grow on minimal media without uridine . The ODC-transformed bacteria expressed up to 24 times the level of activity found in a wild-type E . coli line . The OPRT-transformed E . coli contained only 4-9% of wild-type activity . Western blot analysis with antiserum to human UMP synthase demonstrates that OPRT and ODC domains are being produced in the deficient cells by the respective vectors . The level of the domain protein approximates the level of enzyme activity . The complementation of the OPRT and ODC activities in the transformed deficient E . coli strains demonstrates that human UMP synthase can be separated into active monofunctional domains that will function in the bacterial cell environment.

J Pediatr Surg, 1993 Mar, 28(3), 428 - 33; discussion 433-4
Biology of fetal repair: the presence of bacteria in fetal wounds induces an adult-like healing response; Frantz FW et al.; The minimal acute inflammatory response to tissue injury is one of the most dramatic differences between fetal and adult wound healing . Considering the prominent role of inflammation in adult tissue repair, this study tested the hypothesis that the minimal fetal inflammatory response to tissue injury plays a central role in the "scarless" fetal repair process . Sponge implants were treated with lethally irradiated or live bacteria and placed subcutaneously in fetal rabbits to test the ability of the fetus to mount an acute inflammatory response to bacterial antigens present at the wound site and to analyze the effects of this inflammatory response on fetal fibroplasia and neovascularization . After harvest, these implants were examined histologically for inflammation, fibroblast infiltration, collagen deposition, and neovascularization, and collagen deposition was measured using hydroxyproline quantitation by high-performance liquid chromatography . Bacteria-treated implants showed dose-dependent acute inflammatory responses and significant increases in collagen deposition compared with control sponges . Implants containing live bacteria demonstrated maximal fibroplasia and neovascularization . These findings suggest that, despite neutropenia and immaturity of the fetal immune system, the fetus is capable of mounting an acute inflammatory response to avirulent bacteria present at the wound site . Fetal inflammatory cells which respond to this bacterial stimulus appear capable of initiating an adult-like healing response . Thus, by failing to provide a bacterial stimulus for leukocyte recruitment at the site of tissue injury, the sterile fetal environment appears to play a role in effecting "scarless" fetal wound healing.

Microbiol Rev, 1993 Mar, 57(1), 164 - 82
Ether polar lipids of methanogenic bacteria: structures, comparative aspects, and biosyntheses; Koga Y et al.; Complete structures of nearly 40 ether polar lipids from seven species of methanogens have been elucidated during the past 10 years . Three kinds of variations of core lipids, macrocyclic archaeol and two hydroxyarchaeols, were identified, in addition to the usual archaeol and caldarchaeol (for the nomenclature of archaeal {archaebacterial} ether lipids, see the text) . Polar head groups of methanogen phospholipids include ethanolamine, serine, inositol, N-acetylglucosamine, dimethyl- and trimethylaminopentanetetrol, and glucosaminylinositol . Glucose is the sole hexose moiety of glycolipids in most methanogens, and galactose and mannose have been found in a few species . Methanogen lipids are characterized by their diversity in phosphate-containing polar head groups and core lipids, which in turn can be used for chemotaxonomy of methanogens . This was shown by preliminary simplified analyses of lipid component residues . Core lipid analysis by high-pressure liquid chromatography provides a method of determining the methanogenic biomass in natural samples . There has been significant progress in the biosynthetic studies of methanogen lipids in recent years . In vivo incorporation experiments have led to delineation of the outline of the synthetic route of the diphytanylglycerol ether core . The mechanisms of biosynthesis of tetraether lipids and various polar lipids, and cell-free systems of either lipid synthesis, however, remain to be elucidated . The significance and the origin of archaeal ether lipids is discussed in terms of the lipid composition of bacteria living in a wide variety of environments, the oxygen requirement for biosynthesis of hydrocarbon chains, and the physicochemical properties and functions of lipids as membrane constituents.

Zentralbl Veterinarmed B, 1993 Mar, 40(2), 97 - 104
Identification of Moraxella-like bacteria isolated from caprine and ovine nasal flora; Kodjo A et al.; Twenty four Moraxella related bacterias were isolated from healthy caprine and ovine nasal swabs and were investigated by classic biochemical tests and by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins in comparison with 9 reference strains . Proteolytic and haemolytic strains were investigated by electron microscopy . The biochemical results clustered field isolates in four groups corresponding to Branhamella and Moraxella species . Proteolytic, haemolytic and fimbriated field isolates showed the same morphological structure and biochemical features as Moraxella bovis . SDS-PAGE results indicated that DICE coefficient between a field isolate and the corresponding reference strain can be as 62.5%; 41.7% and 36% respectively for the groups 1, 3 and 4 . The group 2 showed a similarity percentage over 75% with the reference strain Moraxella nonliquefaciens . This results indicated that a non proteolytic but haemolytic bacteria, closely related to Moraxella nonliquefaciens was commonly isolated from small ruminants nasal flora . These animals can also be hosts of a subspecies of Moraxella bovis.

J Immunoassay, 1993 Mar-Jun, 14(1-2), 63 - 81
Evaluation of mouse salivary IgA directed against indigenous oral bacteria; Marcotte H et al.; We are developing an ELISA to follow the evolution of specific salivary IgA directed against the indigenous oral bacteria of the BALB/c mouse . To reduce the variability of the IgA levels detected between different mice, we standardized the method used for sampling saliva and the method used for bacterial cell fixation . Incubation of whole bacteria for one hour at 4 degrees C in poly-L-lysine-treated plates followed by glutaraldehyde fixation increased ELISA reactivities by improving cell fixation . Our results also indicate that salivary IgA concentrations in BALB/c mice peak at the age of three months and that biweekly carbachol-stimulated saliva sampling does not significantly affect the amount of salivary IgA detected.

Eur J Biochem, 1993 Feb 1, 211(3), 663 - 9
Inhibition of proton-translocating transhydrogenase from photosynthetic bacteria by N,N'-dicyclohexylcarbodiimide; Palmer T et al.; The effects of N,N'-dicyclohexylcarbodiimide {(cHxN)2C} on the proton-translocating enzyme, NAD(P) H(+)-transhydrogenase (H(+)-Thase), from two species of phototrophic bacteria have been investigated . The polypeptides of H(+)-Thase from Rhodobacter capsulatus are membrane-associated, requiring detergent to maintain solubility . The enzyme from Rhodospirillum rubrum, however, has a water soluble polypeptide (Ths) and a membrane-associated component (Thm) which, separately, have no activity but which can be fully reconstituted to give a functional complex . Two observations suggest that (cHxN)2C inhibited H(+)-Thase from both species by modification either close to or at the NADP(H)-binding site on the enzyme: (a) the presence of NADP+ or NADPH caused increased inhibition by (cHxN)2C and (b) after treatment of the purified enzyme from Rb . capsulatus with (cHxN)2C, the release of NADP+ became rate-limiting, as evidenced by a stimulated rate of NADPH-dependent reduction of acetylpyridine adenine dinucleotide by NADH . Experiments in which Ths and Thm from R . rubrum were separately treated with (cHxN)2C then reconstituted with the complementary, untreated component revealed that the NADP(H)-enhanced modification by (cHxN)2C was confined to Thm . In contrast to some experiments with mitochondrial H(+)-Thase {Wakabayashi, S . & Hatefi, Y . (1987) Biochem . Int . 15, 667-675}, there was no protective effect of either NAD+ or NADH on the inhibition by (cHxN)2C of enzyme from photosynthetic bacteria . However, amino acid sequence analysis of proteolytic fragments of Ths revealed that the NAD(H)-protectable, (cHxN)2C-reactive glutamate residue in mitochondrial H(+)-Thase might be replaced by glutamine in R . rubrum.

Appl Environ Microbiol, 1993 Feb, 59(2), 644 - 7
p-Coumaroyl and feruloyl arabinoxylans from plant cell walls as substrates for ruminal bacteria; Akin DE et al.; Growth of the ruminal bacteria Ruminococcus flavefaciens FD1, Selenomonas ruminantium HD4, and Butyrivibrio fibrisolvens 49 was limited by ester-linked feruloyl and p-coumaroyl groups . The limitation of growth on phenolic acid-carbohydrate complexes varied with individual bacteria and appeared to be influenced by ability to hydrolyze carbohydrate linkages.

Infect Immun, 1993 Feb, 61(2), 742 - 50
Identification of a Mycobacterium bovis BCG 45/47-kilodalton antigen complex, an immunodominant target for antibody response after immunization with living bacteria; Romain F et al.; Increased protection against a virulent challenge with Mycobacterium tuberculosis is induced mainly by a previous immunization with living avirulent mycobacteria, usually Mycobacterium bovis BCG . Only a transient and marginal protection is obtained after immunization with bacterial extracts or dead bacteria . Both living and heat-killed bacteria share a number of common antigens . In order to identify mycobacterial molecules which are dominant antigens during immunization with living bacteria, a two-step selection method was used . Two groups of guinea pigs were immunized either with living or with heat-killed BCG . Sera were then collected and used to select and counterselect antigens present in BCG culture filtrates . Each major fraction eluted from a series of high-pressure liquid chromatography columns (gel filtration, DEAE, and reverse-phase chromatography) was run on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred on polyvinylidene difluoride sheets . The molecules present on twin immunoblots were stained with antibodies raised in guinea pigs immunized either with living or with heat-killed BCG . Cross-reactive antigens stained in twin immunoblots were eliminated . Major antigens interacting with antibodies raised after immunization only with living bacteria were further purified . A complex of 45- and 47-kDa major molecules (45/47-kDa complex) was thus identified and further purified . The complex was found to interact only with antibodies present in sera of guinea pigs immunized with living bacteria and not at all with antibodies raised after immunization with dead bacteria . The 45/47-kDa antigen complex molecules were resolved on two-dimensional electrophoresis in three major and seven minor proteins detected with silver staining . All the molecules interacted with the antibodies present in sera of guinea pigs immunized with living BCG . The three major proteins (two at 47 kDa and one at 45 kDa) were amino-terminal sequenced . The sequence A-P-E-P-A-P-P-V-P-P-A-A-A-A-P-P-A, which was not previously reported, was the same for these three molecules . By using a competitive enzyme-linked immunosorbent assay, the concentrations of the 45/47-kDa antigen complex were measured in BCG culture filtrates, freeze-dried BCG, and dried heat-killed BCG; they were, respectively, 2, 0.01, and 0.001% of the total mass . The low or very low values compared with the high antibody concentration emphasized the ability of the 45/47-kDa complex delivered through live BCG to trigger an antibody response.

J Virol, 1993 Feb, 67(2), 989 - 96
RNA-stimulated NTPase activity associated with yellow fever virus NS3 protein expressed in bacteria; Warrener P et al.; The nonstructural protein NS3 of the prototypic flavivirus, yellow fever virus, was investigated for possession of an NTPase activity . The entire NS3 protein coding sequence and an amino-terminal truncated version thereof were engineered into Escherichia coli expression plasmids . Bacteria harboring these plasmids produced the expected polypeptides, which upon cell disruption were found in an insoluble aggregated material considerably enriched for the NS3-related polypeptides . Solubilization and renaturation of these materials, followed by examination of their ability to hydrolyze ATP, revealed an ATPase activity present in both the full-length and amino-terminal truncated NS3 preparations but not in a similarly prepared fraction from E . coli cells engineered to express an unrelated polypeptide . The amino-terminal truncated NS3 polypeptide was further enriched to greater than 95% purity by ion-exchange and affinity chromatography . Throughout the purification scheme, the ATPase activity cochromatographed with the recombinant NS3 polypeptide . The enzymatic activity of the purified material was shown to be a general NTPase and was dramatically stimulated by the presence of particular single-stranded polyribonucleotides . These results are discussed in view of similar activities identified for proteins of other positive-strand RNA viruses.

Biull Eksp Biol Med, 1993 Feb, 115(2), 180 - 3
{Antihistone activity of bacteria}; Sokolov VIu; For the first time an anti-histone activity of bacteria has been revealed and a method of its determination has been suggested . Bacteria used in the study and isolated from anterior section of nasal mucosa of the children have been identified on a species level and characterized in terms of their antihistone activity . With employment of light microscopic technique different stages of interaction between bacteria and nuclei of epitheliocytes of anterior section of nasal mucous membrane of children under school age were studied . A biological significance of antihistone activity of bacteria as well as a possibility of its use in biotechnology, Medicine, Ecology is discussed.

J Theor Biol, 1993 Jan 21, 160(2), 249 - 64
Does HIV "piggyback" on CD4-like surface proteins of sperm, viruses, and bacteria? Implications for co-transmission, cellular tropism and the induction of autoimmunity in AIDS; Root-Bernstein RS et al.; Coinfections of human immunodeficiency virus (HIV), EBV, and HTLV or sperm proteins act synergistically to enhance infectivity and replication and expand cellular tropism . While some aspects of these synergisms are understood, others are not . We have found that membrane or surface proteins of CMV, HTLV, EBV and sperm proteins share large regions of similarity with the CD4 protein of T-helper lymphocytes . Since HIV uses CD4 as a receptor, it may bind to CD4 homologues on CMV, HTLV, EBV or sperm proteins . HIV could then "piggyback" with these viruses into cells with which it normally has no tropism . Similarly, HIV may expand the cellular tropism of CMV, or EBV . Such a piggyback mechanism may provide insight into the formation or presentation of CD4-like antigens from CMV, HTLV, EBV and sperm proteins with class II MHC-like antigens on HIV (gp160 and Nef proteins) and may break immunological tolerance, inducing the autoimmunity observed against both CD4+ and class II MHC+ T cells in AIDS patients.

Bioessays, 1993 Jan, 15(1), 17 - 24
Exploitation of host signal transduction pathways and cytoskeletal functions by invasive bacteria; Rosenshine I et al.; Many bacteria that cause disease have the capacity to enter into and live within eukaryotic cells such as epithelial cells and macrophages . The mechanisms used by these organisms to achieve and maintain this intracellular lifestyle vary considerably, but most mechanisms involve subversion and exploitation of host cell functions . Entry into non-phagocytic cells involves triggering host signal transduction mechanisms to induce rearrangement of the host cytoskeleton, thereby facilitating bacterial uptake . Once inside the host cell, intracellular pathogens either remain within membrane bound inclusions or escape to the cytoplasm . Those living in the cytoplasm can further pirate the host actin system, using actin as a mechanism to facilitate movement within and between host cells . Organisms remaining within the vacuole have specialized mechanisms for intracellular survival and growth which involve additional communication with the host cell . Some of the processes involved in the various steps of facultative intracellular parasitism are discussed in the context of subverting the host cell cytoskeleton and signal transduction pathways for bacterial benefit.

Arch Microbiol, 1993, 159(2), 101 - 8
Expression study with the Escherichia coli lep gene for leader peptidase in phototrophic purple bacteria; Dierstein R et al.; Synthesis and assembly of leader peptidase of Escherichia coli (signal peptidase I), was studied by heterologous expression of its lep gene in three species of phototrophic purple bacteria . Cell extracts of the recipient species showed neither cross reaction with antibodies against E . coli leader peptidase nor cleavage of the model substrate M13-procoat in vitro . The lep gene was transferred via conjugation using the plasmid expression vector for phototrophic bacteria pJAJ9 . Plasmid-borne leader peptidase enzyme was identified by immunochemical means . However, extracts of transconjugant cells showed no cleavage function . Trypsin digestion studies revealed that the enzyme was not properly integrated across the host membranes . The data suggest that cleaving enzymes for protein export and/or their assembly pathway in purple bacteria differ from the E . coli type.

Mol Microbiol, 1993 Jan, 7(1), 1 - 5
Copper uptake and resistance in bacteria; Cooksey DA; Copper ions are essential for bacteria but can cause a number of toxic cellular effects if levels of free ions are not controlled . Investigations of copper-resistant bacteria have revealed several mechanisms, mostly plasmid-determined, that prevent cellular uptake of high levels of free copper ions . However, these studies have also revealed that bacteria apparently have efficient chromosomally encoded systems for uptake and management of trace levels of copper . This review will explore the relationship of copper uptake systems to resistance mechanisms and the possibility that copper resistance has evolved directly through modification of chromosomal copper uptake genes.

J Cell Biochem, 1993 Jan, 51(1), 47 - 54
Gene regulation by phosphate in enteric bacteria; Wanner BL; The Escherichia coli phosphate (PHO) regulon includes 31 (or more) genes arranged in eight separate operons . All are coregulated by environmental (extra-cellular) phosphate and are probably involved in phosphorus assimilation . Pi control of these genes requires the sensor PhoR, the response regulator PhoB, the binding protein-dependent Pi-specific transporter Pst, and the accessory protein PhoU . During Pi limitation, PhoR turns on genes of the PHO regulon by phosphorylating PhoB that in turn activates transcription by binding to promoters that share an 18-base consensus PHO Box . When Pi is in excess, PhoR, Pst, and PhoU together turn off the PHO regulon, presumably by dephosphorylating PhoB . In addition, two Pi-independent controls that may be forms of cross regulation turn on the PHO regulon in the absence of PhoR . The sensor CreC, formerly called PhoM, phosphorylates PhoB in response to some (unknown) catabolite, while acetyl phosphate may directly phosphorylate PhoB . Cross regulation of the PHO regulon by CreC and acetyl phosphate may be examples of underlying control mechanisms important for the general (global) control of cell growth and metabolism.

FEMS Microbiol Rev, 1993 Jan, 10(1-2), 1 - 38
Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria; Willison JC; The biochemical genetics approach is defined as the use of mutants, in comparative studies with the wild-type, to obtain information about biochemical and physiological processes in complex metabolic systems . This approach has been used extensively, for example in studies on the bioenergetics of the photosynthetic bacteria, but has been applied less frequently to studies of intermediary carbon and nitrogen metabolism in phototrophic organisms . Several important processes in photosynthetic bacteria--the regulation of nitrogenase synthesis and activity, the control of intracellular redox balance during photoheterotrophic growth, and chemotaxis--have been shown to involve metabolism . However, current understanding of carbon and nitrogen metabolism in these organisms is insufficient to allow a complete understanding of these phenomena . The purpose of the present review is to give an overview of carbon and nitrogen metabolism in the photosynthetic bacteria, with particular emphasis on work carried out with mutants, and to indicate areas in which the biochemical genetics approach could be applied successfully . In particular, it will be argued that, in the case of Rhodobacter capsulatus and Rb . sphaeroides, two species which are fast-growing, possess a versatile metabolism, and have been extensively studied genetically, it should be possible to obtain a complete, integrated description of carbon and nitrogen metabolism, and to undertake a qualitative and quantitative analysis of the flow of carbon and reducing equivalents during photoheterotrophic growth . This would require a systematic biochemical genetic study employing techniques such as HPLC, NMR, and mass spectrometry, which are briefly discussed . The review is concerned mainly with Rb . capsulatus and Rb . sphaeroides, since most studies with mutants have been carried out with these organisms . However, where possible, a comparison is made with other species of purple non-sulphur bacteria and with purple and green sulphur bacteria, and recent literature relevant to these organisms has been cited.

Dig Dis Sci, 1993 Jan, 38(1), 39 - 44
Bile-induced acute pancreatitis in cats . Roles of bile, bacteria, and pancreatic duct pressure; Arendt T; The relationship between pancreatic duct pressure, bile, bacterial infection of bile, and the development of acute pancreatitis was studied in a feline model . The cat main pancreatic duct was perfused from the head to the tail of the gland with bile and/or Escherichia coli bacteria at "basal" pancreatic duct pressure (< 10 cm H2O) and at pancreatic duct pressure in the upper physiologic range (45 cm H2O) . Sterile bile and sterile control solution produced no inflammatory alterations at either pressure . Infected control solution caused a mild acute edematous pancreatitis under low and high pressure . Infected bile caused a severe acute edematous pancreatitis at basal duct pressure; at high pressure, additional focal acinar necrosis was observed in the majority of animals . Infected bile was found to raise basal pancreatic duct pressure by 30% . The other test solutions, which caused only mild inflammatory alterations of the pancreas, did not alter duct pressure . We conclude: (1) Bacterial infection is important for the initiation of acute pancreatitis in this model . (2) High physiologic duct pressure may result in the conversion of nondestructive forms of the inflammation to acinar necrosis . (3) Infected bile-induced increase in duct pressure is likely to result from compression of the duct lumen by the inflammatory edema of the gland.

J Cell Physiol, 1993 Jan, 154(1), 1 - 6
Inhibitory effects of a bacteria-derived sulfated polysaccharide against basic fibroblast growth factor-induced endothelial cell growth and chemotaxis; Nakayama Y et al.; The effects of sulfated polysaccharides on the growth and chemotaxis of endothelial cells promoted by basic fibroblast growth factor (bFGF), a heparin-binding growth factor, and epidermal growth factor (EGF), a non-heparin-binding growth factor, were examined . The binding abilities of these two growth factors to D-gluco-D-galactan sulfate (DS-4152) were the same as to heparin . DS-4152 inhibited the growth and chemotaxis of the cells stimulated by bFGF, and prevented the binding of bFGF to the cells at both its low and high affinity binding sites: the former and the latter are heparin-like molecules and receptor proteins for bFGF, respectively . However, DS-4152 affected neither the binding of EGF to endothelial cells nor the proliferation and chemotaxis of the cells stimulated by the factor . Heparin also inhibited the binding of bFGF to low affinity binding sites to the same degree as DS-4152, but had little effect on the binding of bFGF to high affinity sites and no effects on bFGF-induced endothelial cell growth . Chondroitin sulfate A prevented neither the binding of bFGF to both sites of the cells nor bFGF-induced cell proliferation . We thus concluded that the inhibitory effects of DS-4152 against the growth and chemotaxis of endothelial cells induced by bFGF might be due to the prevention of bFGF binding to its receptor proteins resulting from the binding of DS-4152 to bFGF.

Trop Geogr Med, 1993, 45(3), 117 - 20
Preliminary epidemiological studies on tetracycline resistant plasmids isolated from enteric bacteria in Nigeria; Olukoya DK et al.; In an epidemiological investigation on the genetic determinants responsible for tetracycline resistance in Nigeria, 518 isolates of enteric bacteria from hospitals and clinics were screened for susceptibility to antibiotics . 305 (58.8%) were resistant to tetracycline . The commonest resistance pattern that involved tetracycline resistance was tetr ampr sxtr Smr . Of the 305 isolates, 207 (67.8%) transferred resistant plasmids to Escherichia coli K-12 . Altogether, 12 types of plasmids were isolated depending on the phenotypes of antibiotics resistant character borne on the plasmids; they ranged in sizes between 3 to 180 kilobases . The plasmids were evenly distributed in the country . Thus R plasmids are a major reason for resistance to tetracycline encountered in Nigeria.

J Cell Biochem, 1993 Jan, 51(1), 1 - 6
Introduction: protein phosphorylation and signal transduction in bacteria; Saier MH Jr; A single type of reversible protein-phosphorylating system, the ATP-dependent protein kinase/phosphatase system, is employed in signal transduction in eukaryotes . By contrast, recent work has revealed that three types of protein-phosphorylating systems mediate signal transduction in bacteria . These systems are (1) classical protein kinase/phosphatase systems, (2) sensor-kinase/response-regulator systems, and (3) the multifaceted phosphoenolpyruvate-dependent phosphotransferase system . Physiological, structural, and mechanistic aspects of these three evolutionarily distinct systems are discussed in the papers of this written symposium.

Pneumonol Alergol Pol, 1993, 61(3-4), 138 - 43
{Effect of bacteria on chemotaxis of peripheral blood lymphocytes from nonatopic asthmatics}; Zak-Nejmark T et al.; The chemotactic response of peripheral blood lymphocytes from nonatopic asthmatics and healthy subjects in the gradients of various bacterial strains obtained from the airways of the asthmatic patients was investigated . The dominant autologous strains were found to be effective chemoattractants for lymphocytes form the asthmatics . However, none of the bacterial strains investigated in this study induced increased motility of lymphocytes from healthy subjects . These findings might explain the mechanisms of the accumulation of lymphocytes in the airways of nonatopic asthmatics.

J Biomater Sci Polym Ed, 1993, 4(6), 567 - 78
Migration of bacteria along synthetic polymeric fibers; Mahmoud WM et al.; E . coli, S . epidermidis, and B . distasonis were observed to migrate readily along polymer fibers impressed upon the surface of nutrient agar . E . coli was also observed to migrate readily along polymer fibers embedded in brain-heart infusion agar . Within periods of about 24 h, migration distances of about several centimeters were observed . No migration was observed in control experiments conducted on or in the same media, but without fibers . Migration speed was greatest for E . coli and slowest for B . distasonis . Cell population density was found to decrease rapidly with distance from a source culture . Swimming motility or natural convection in liquid between fiber and gel appears to be improbable based on the expected dimensions of capillary-condensed liquid between fiber and gel.

Annu Rev Microbiol, 1993, 47, 139 - 66
Suicidal genetic elements and their use in biological containment of bacteria; Molin S et al.; The potential risks of unintentional releases of genetically modified organisms, and the lack of predictable behavior of these in the environment, are the subject of considerable concern . This concern is accentuated in connection with the next phase of gene technology comprising deliberate releases . The possibilities of reducing such potential risks and increasing the predictability of the organisms are discussed for genetically engineered bacteria . Different approaches towards designing disabled strains without seriously reducing their beneficial effects are presented . Principally two types of strain design are discussed: actively contained bacteria based on the introduction of controlled suicide systems, and passively contained strains based on genetic interference with their survival under environmental-stress conditions.

Pathobiology, 1993, 61(2), 95 - 7
Accurate flow cytometric measurement of bacteria concentrations; Cantinieaux B et al.; Accurate measurements of bacteria concentrations are required in numerous studies; they raise methodological problems that complicate, for instance, the investigations of polymorphonuclear neutrophil functions . We propose a new flow cytometric method of determining bacteria concentrations by comparison with a standardized fluorescent latex bead solution . Relative counts of beads and bacteria are established in a system using both fluorescence and light scatter for the two types of particles . On the one hand, the latex bead size (0.98 microns in diameter) permits counting on traditional hematological counters and, on the other, a flow cytometric detection with the same conditions for bacteria . The reproducibility of the study of bacteria concentration measurements gave a coefficient of variation of < 5%.

Reprod Nutr Dev, 1993, 33(3), 283 - 8
Interactions between proteolytic and cellulolytic rumen bacteria during hydrolysis of plant cell wall protein; Debroas D et al.; During the degradation of the plant cell wall protein of dried alfalfa, interactions may occur between hydrolytic activities of cellulolytic (Ruminococcus albus or Fibrobacter succinogenes) and proteolytic (Prevotella ruminicola or Butyrivibrio fibrisolvens) bacteria . In vitro the hydrolysis of these protein compounds begins after the depolymerization of the cell wall polysaccharides has started . Maximal degradation of cell wall protein of dried alfalfa (37.2%) was obtained with cocultures of Prevotella ruminicola and Ruminococcus albus.

Nephron, 1993, 64(3), 405 - 9
Renal scarring is enhanced by phorbol myristate acetate following infection with bacteria with mannose-sensitive pili; Matsumoto T et al.; Renal scarring is considered to develop in the later stages of chronic pyelonephritis . In our experimental model of pyelonephritis, bacteria with mannose-sensitive (MS) pili on their surface promoted renal scarring following inoculation into the renal parenchyma . The administration of cyclophosphamide to induce leukopenia and of superoxide dismutase to inactivate superoxide released from polymorphonuclear leukocytes (PMN) at the infection site suppressed any renal scarring following the infection . Conversely, the administration of phorbol myristate acetate at an early stage of infection significantly enhanced the renal scarring . These findings suggest that the PMNs which infiltrate the infection site and the superoxide they release play an important role in any renal scarring following infection with MS-piliated bacteria.

Antonie Van Leeuwenhoek, 1993-94, 64(3-4), 285 - 305
Phylogenetic relationships of Bacteria based on comparative sequence analysis of elongation factor Tu and ATP-synthase beta-subunit genes; Ludwig W et al.; Comparative sequence analyses were performed on 14 genes encoding bacterial elongation factors EF-Tu and 7 genes encoding the beta-subunit of bacterial F1F0 type ATP-synthases . The corresponding predicted amino acid sequences were compared with published primary structures of homologous molecules . Phylogenetic trees were reconstructed from both data sets of aligned protein sequences and from an equivalent selection of 16S rRNA sequences by applying distance matrix and maximum parsimony methods . The EF-Tu data were in very good agreement with the rRNA data, although the resolution within the EF-Tu tree was reduced at certain phylogenetic levels . The resolution power of the ATPase beta-subunit sequence data were more reduced than those of the EF-Tu data . In comparison with the 16S rRNA tree there are minor differences in the order of adjacent branchings within the ATPase beta-subunit tree.

Cytotechnology, 1993, 11 Suppl 1, S83 - 5
Interpretation of gascromatographic data via artificial neural networks for the classification of marine bacteria; Ruggiero C et al.; We propose a new method for classification of marine bacteria . This method uses gaschromatograms, which contain information of fatty acid percentage contents of the fresh isolate . For the interpretation of these gaschromatograms we use a surpervisioned artificial neural network . We present a preliminary study on this matter, whose first results show good convergence and classification features.

Arch Microbiol, 1993, 160(3), 238 - 40
Phylogenetic analysis of Syntrophobacter wolinii reveals a relationship with sulfate-reducing bacteria; Harmsen HJ et al.; A 16S rRNA sequence analysis of Syntrophobacter wolinii was done by using PCR amplification of the 16S rRNA-genes from DNA isolated from the S . wolinii-Desulfovibrio sp . coculture . Phylogenetic analysis using the obtained sequence revealed that S . wolinii was not related to bacteria growing syntrophically on other fatty acids than propionate, but was related to sulfate-reducing bacteria . The closest related bacteria are Desulfomonile tiedjei and Desulfoarculus baarsii.

Ren Fail, 1993, 15(2), 141 - 8
Effect of recombinant human granulocyte-colony-stimulating factor on renal scarring following infection with MS-piliated bacteria; Haraoka M et al.; Renal scars have been thought to occur only in later stages of chronic pyelonephritis . In our experimental pyelonephritis model, bacteria with mannose-sensitive (MS) pili on its surface promoted renal scarring when inoculated into renal parenchyma . Pretreatment with recombinant human granulocyte-colony-stimulating factor (rhGCSF) inhibited the renal scarring which followed inoculation with MS-piliated bacteria, whereas posttreatment at an early stage of infection had no effect on renal scarring . These findings suggest that rhGCSF may be useful for the prevention of infection without increasing the tissue damage to the renal parenchyma which leads to the renal scarring . Even when rhGCSF is used for treatment of kidney infection, it does not promote increased renal scarring through the increased invasion of leukocytes at the inflammatory site.

Annu Rev Microbiol, 1993, 47, 321 - 50
Regulation of the heat-shock response in bacteria; Yura T et al.; When bacteria cells are exposed to higher temperature, a set of heat-shock proteins (hsps) is induced rapidly and transiently to cope with increased damage in proteins . The mechanism underlying induction of hsps has been a central issue in the heat-shock response and studied intensively in Escherichia coli . Immediately upon temperature upshift, the cellular level of sigma 32 responsible for transcription of heat-shock genes increases rapidly and transiently . The increase in sigma 32 results from both increased synthesis and stabilization of sigma 32, which is ordinarily very unstable . A clue to further understanding of early regulatory events came from recent analysis of translational induction and subsequent shut-off of sigma 32 synthesis . Whereas a 5'-coding region of mRNA for sigma 32 is involved in the induction mediated by the mRNA secondary structure, a distinct segment of sigma 32 polypeptide further downstream is involved in the DnaK/DnaJ-mediated shut-off and destabilization of sigma 32 that may be mutually interconnected.

J Commun Dis, 1992 Dec, 24(4), 206 - 10
Evaluation of the common cockroach Periplaneta americana (L.) as carrier of medically important bacteria; Paul S et al.; The bacterial flora associated with external body parts, stomach and intestine of male and female Periplaneta americana inhabitating students' halls, teachers' residences and houses of low-paid employees in Jahangirnagar, University Campus were examined and analysed qualitatively and quantitatively . The qualitative study in P . americana revealed the presence of 31 species of bacteria belonging to 16 genera . Most of these bacteria are pathogenic to man and domestic animals . The total viable bacterial counts (TVBC/g) in students' halls, teachers' residences and houses of low-paid employees were 1.27 x 10(8), 6.04 x 10(7) and 1.65 x 10(8) respectively in the male and 1.43 x 10(8), 5.83 x 10(7) and 1.63 x 10(8) respectively in the female cockroaches . The highest prevalence of bacterial flora both in number and types occurred in stomach followed by intestine and the external body parts.

Trends Genet, 1992 Dec, 8(12), 457 - 62
DNA inversions in phages and bacteria; van de Putte P et al.; In certain phages and bacteria, there is a recombination system that specifically promotes the inversion of a DNA fragment . These inversion events appear to act as genetic switches allowing the alternate expression of different sets of genes which in general code for surface proteins . The mechanism of inversion in one class of inversion systems (Gin/Hin) has been studied in detail . It involves the formation of a highly specific nucleoprotein complex in which not only the two recombination sites and the DNA invertase participate but also a recombinational enhancer to which the DNA-bending protein Fis is bound.

J Bioenerg Biomembr, 1992 Dec, 24(6), 587 - 99
Proton-coupled bioenergetic processes in extremely alkaliphilic bacteria; Krulwich TA et al.; Oxidative phosphorylation, which involves an exclusively proton-coupled ATP synthase, and pH homeostasis, which depends upon electrogenic antiport of cytoplasmic Na+ in exchange for H+, are the two known bioenergetic processes that require inward proton translocation in extremely alkaliphilic bacteria . Energy coupling to oxidative phosphorylation is particularly difficult to fit to a strictly chemiosmotic model because of the low bulk electrochemical proton gradient that follows from the maintenance of a cytoplasmic pH just above 8 during growth at pH 10.5 and higher . A large quantitative and variable discrepancy between the putative chemiosmotic driving force and the phosphorylation potential results . This is compounded by a nonequivalence between respiration-dependent bulk gradients and artificially imposed ones in energizing ATP synthesis, and by an apparent requirement for specific respiratory chain complexes that do not relate solely to their role in generation of bulk gradients . Special features of the synthase may contribute to the mode of energization, just as novel features of the Na+ cycle may relate to the extraordinary capacity of the extreme alkaliphiles to achieve pH homeostasis during growth at, or sudden shifts to, an external pH of 10.5 and above.

J Exp Anim Sci, 1992 Dec, 35(3), 103 - 9
Different degree of ileal colonization by segmented, filamentous bacteria in two strains of mice; Klaasen HL et al.; Segmented, filamentous bacteria (SFBs) are autochthonous, apathogenic inhabitants of the ileum of various animal species . Outbred Swiss (Cpb:SE) mice have significantly higher degrees of SFB colonization than do inbred BALB/c mice . The present studies were carried out to identify determinants of this strain difference . In a cross-fostering experiment it was shown that SFB colonization of the pups is determined by the strain of the pups themselves rather than by the strain of the nursing dam . Thus, maternal effects may not be involved in SFB colonization . In a cross-infecting experiment using germ-free and SFB-positive animals of the two mouse strains, it was found that ileal SFB colonization is determined by host characteristics rather than by origin of the SFBs . Thus, SFBs that are specific for a given mouse strain may not exist in the two strains of mice . It is concluded that the mouse strain difference in SFB colonization is determined by host characteristics, which probably have a genetic basis.

Gesundheitswesen, 1992 Dec, 54(12), 716 - 9
{Legionella and other bacteria in air humidifiers and cooling systems of air conditioning units--a survey}; Dermitzel A et al.; Air humidifiers using cold water and cooling towers of air-conditioning systems provide the best settings for the growth of bacteria . Hence, we investigated 90 water samples for humidifiers and 15 water samples from cooling towers of hospitals, authorities, schools, and factories . The colony forming units/ml at 20 degrees C and 36 degrees C, the biological activity of added biocidal substances, and the occurrence of legionella were determined . About 90 percent of the samples showed no activity of the biocidal substance added, suggesting the uselessness of such substances . Furthermore, they exercised neither an influence on the CFU of the water samples nor on the occurrence of legionella . Legionella were isolated in 7 per cent of the humidifiers investigated, in 3 per cent of air conditioned buildings, respectively . 13 per cent of the cooling towers contained legionella . The risk of infection by air conditioning systems, humidifiers, cooling towers, and other emitters of infections agents should be controlled by the public health service.

Science, 1992 Nov 6, 258(5084), 936 - 42
Transport proteins in bacteria: common themes in their design; Nikaido H et al.; Bacterial transport proteins mediate passive and active transport of small solutes across membranes . Comparison of amino acid sequences shows strong conservation not only among bacterial transporters, but also between them and many transporters of animal cells; thus the study of bacterial transporters is expected to contribute to our understanding of transporters in more complex cells . During the last few years, structures of three bacterial outer membrane transporters were solved by x-ray crystallography . Much progress has also occurred in the biochemical and molecular genetic studies of transporters in the cytoplasmic membranes of bacteria, and a unifying design among membrane transporters is gradually emerging . Common structural motives and evolutionary origins among transporters with diverse energy-coupling mechanisms suggest that many transporters contain a central module forming a transmembrane channel through which the solute may pass . Energy-coupling mechanisms can be viewed as secondary features added on to these fundamental translocation units.

J Appl Bacteriol, 1992 Nov, 73(5), 438 - 44
Characterization of bacteria by multiparameter flow cytometry; Allman R et al.; An arc-lamp based flow cytometer was used to obtain high resolution measurements of the light scattering characteristics and DNA contents of eight different bacteria . Light scatter profiles of bacteria are a useful first step when flow cytometry is used to characterize organisms . Scanning and transmission electron microscopy of the bacterial samples demonstrate that the structural basis of the light scattering profiles is not always clear, i.e . some organisms appear to have anomalous light scattering characteristics . The use of a third measurement parameter, DNA content, allowed much better discrimination of the organisms . Flow cytometry shows great promise as a method for the rapid discrimination and identification of bacterial populations.

J Clin Invest, 1992 Nov, 90(5), 1803 - 11
Acquisition and synthesis of folates by obligate intracellular bacteria of the genus Chlamydia; Fan H et al.; We undertook studies focused on folate acquisition by Chlamydia trachomatis L2, Chlamydia psittaci 6BC, and C . psittaci francis . Results from in situ studies, using wild-type host cells, confirmed that C . trachomatis L2 and C . psittaci 6BC are sensitive to sulfonamides whereas C . psittaci francis is resistant . In addition C . trachomatis L2 and C . psittaci francis were inhibited by methotrexate in situ whereas C . psittaci 6BC was not . In contrast to C . trachomatis, neither C . psittaci strain was affected by trimethoprim . Surprisingly our results indicate that all three strains are capable of efficient growth in folate-depleted host cells . When growing in folate-depleted cells C . psittaci francis becomes sensitive to sulfonamide . The ability of all three strains to carry out de novo folate synthesis was demonstrated by following the incorporation of exogenous {3H}pABA into intracellular folates and by detecting dihydropteroate synthase activity in reticulate body crude extract . Dihydrofolate reductase activity was also detected in reticulate body extract . In aggregate the results indicate that C . trachomatis L2, C . psittaci francis, and C . psittaci 6BC can all synthesize folates de novo, however, strains differ in their ability to transport preformed folates directly from the host cell.

DNA Cell Biol, 1992 Nov, 11(9), 701 - 6
Recombinant human acid alpha-glucosidase generated in bacteria: antigenic, but enzymatically inactive; Martiniuk F et al.; Genetic deficiency of acid alpha-glucosidase (GAA) results in glycogen storage disease type II . To investigate whether we could generate a functional recombinant human GAA protein for future enzyme replacement therapy, we subcloned the GAA cDNA into the bacterial expression plasmid pMaI and analyzed the recombinant protein produced . This nonglycosylated recombinant human GAA was found to be antigenic by reacting with polyclonal rabbit antibody to human placental GAA using ELISA and Western techniques . However, the protein was not enzymatically active, suggesting that glycosylation may play a role in enzymatic function.

Bioessays, 1992 Nov, 14(11), 757 - 62
The molecular and cell biology of anion transport by bacteria; Maloney PC; This article summarizes the study of anion exchange mechanisms in bacteria . Along with defining at least two different families of anion exchange, an examination of such carrier-mediated antiport reactions has led to techniques that considerably broaden the scope of biochemical methods for examining membrane proteins . Such advances have been exploited to show that anion exchange itself forms the mechanistic base of an entirely new kind of proton pump, one which may shed light on a variety of bacterial events, including methanogenesis . Perhaps most important, the study of exchange provided the final link in a chain of evidence pointing to a structural 'rhythm' that seems to characterize membrane carriers . These three issues--a biochemical tool, a new proton pump, and a common structural rhythm--are briefly examined in the context of their origins in the analysis of bacterial anion exchange.

J Med Virol, 1992 Nov, 38(3), 214 - 9
Use of antigen expressed in bacteria for detection of EBV-specific thymidine kinase antibodies in sera from patients with nasopharyngeal carcinoma; Hsu TY et al.; Two cDNA clones covering the N- and C-terminal portions of the EBV BXLF1 open reading frame were selected from a cDNA library derived from P3HR1 cells . The two clones were ligated, the N-terminal untranslated region truncated, and the product inserted into an E . coli expression vector, pET3CP* . The fusion protein was expressed under control of the T7 phage phi 10 gene promoter and shown to possess thymidine kinase activity . The protein was then used as an antigen to detect antibody reactivities in serum samples of nasopharyngeal carcinoma patients and healthy blood donors . Using a 1:400 dilution of serum samples in Western blot analyses, it was possible to differentiate the reactivities of serum IgA of NPC patients and healthy donors . The prevalence of positive reactivity to EBV TK in NPC was around 84% . The test was compared to others used for early diagnosis of NPC and was able to detect some patients who were negative in those tests.

Orv Hetil, 1992 Oct 18, 133(42), 2683 - 4, 2687-8
{Significance of leukocytes and bacteria in the gastric aspirate from neonates}; Gabriel A et al.; The cytological pictures of the gastric aspirates of 2582 newborns were evaluated by a semiquantitative method . A high number of germs was found in the majority of the early onset sepsis and pneumonia (19/22) . In the late onset and local connatal infections were found no significant cytological abnormalities . A high number of germs was a rare finding in the healthy newborn population (11/2456).

Int J Syst Bacteriol, 1992 Oct, 42(4), 645 - 8
Use of 16S rRNA analysis to investigate phylogeny of methylotrophic bacteria; Bratina BJ et al.; Small-subunit rRNAS from 24 gran-negative methylotropic bacteria have been sequenced . A phylogenetic tree was constructed on the basis of sequence similarities by using a weighted least-mean-square difference method . The methylotrophs were separated into coherent clusters in which bacteria in each group shared physiological characteristics.

Prog Food Nutr Sci, 1992 Oct-Dec, 16(4), 307 - 43
The production of menaquinones (vitamin K2) by intestinal bacteria and their role in maintaining coagulation homeostasis; Conly JM et al.; Vitamin K is an essential cofactor necessary for the production of clotting factors II, VII, IX, and X in humans and has recently been found to be an essential factor for many other proteins in the body . There are two sources of this essential vitamin, including vitamin K1, or phylloquinone which is primarily found in green leafy vegetables and vitamin K2 or menaquinone which is synthesized by certain intestinal bacteria . The precise contribution of the bacterially synthesized menaquinone to overall vitamin K requirements in man is unknown . This paper reviews the available literature regarding the production and liberation of menaquinones from bacteria, the animal experiments which have been done to examine the absorption of menaquinones and the indirect and direct evidence in humans regarding utilization of menaquinones . The preponderance of the evidence suggests that bacterially synthesized menaquinones, particularly in the ileum can and do play a significant role in contributing to vitamin K requirements in humans to prevent clinically significant coagulopathy, especially during periods of episodic dietary lack of the vitamin.

J Am Soc Nephrol, 1992 Oct, 3(4), 1002 - 7
A prospective study of pyrogenic reactions in hemodialysis patients using bicarbonate dialysis fluids filtered to remove bacteria and endotoxin; Pegues DA et al.; Pyrogenic reactions (PR) are a well-recognized complication of hemodialysis and have been associated with dialyzer reuse, high-flux dialysis, and bicarbonate dialysate . However, the roles of bacteria and endotoxin in dialysate for producing PR are not well defined . To determine the effect of removing most bacteria and endotoxin from the dialysate on the incidence of PR, a cohort of chronic hemodialysis patients receiving high-flux, high-efficiency, or conventional hemodialysis at three centers with bicarbonate dialysis fluids that had been filtered with a polysulfone high-flux hemodialyzer was prospectively studied . Unfiltered bicarbonate concentrate had median bacterial and endotoxin concentrations of 479,000 CFU/mL and 39,800 pg/mL, respectively . After filtration of the bicarbonate concentrate at the central proportioner, dialysate had a median 9.2 CFU/mL of bacteria and 17.8 pg/mL of endotoxin . Dialysate filtered at individual proportioning dialysis machines had a median 0.001 CFU/mL of bacteria and 0.19 pg/mL of endotoxin . Nine PR were identified among 303 patients after 28,007 hemodialysis treatments (0.3 PR/1,000 treatments) . The rate of PR was similar for the three hemodialysis treatment modalities and for first-use compared with reused dialyzers . Although the PR rate in this study was lower (P = 0.046) than the PR rate of a previous study with unfiltered dialysis fluids (0.7 PR/1,000 treatments), it represents a difference of only 10 PR in over 28,000 treatments . It was concluded that filtration of hemodialysis fluids is efficacious in removing bacterial and endotoxin contamination and can result in a lower incidence of PR in patients receiving high-flux, high-efficiency, or conventional hemodialysis.

Arch Oral Biol, 1992 Oct, 37(10), 821 - 9
Comparison of the effects of galactose and glucose on the pH responses of human dental plaque, salivary sediment and pure cultures of oral bacteria; Salako NO et al.; Comparisons made in dental plaque in vivo demonstrated that galactose produces a significantly smaller decrease in pH than does glucose . In vitro studies with plaque, salivary sediment and pure cultures of oral bacteria done in the absence of intraoral factors such as flowing saliva confirmed this lesser acidogenicity of galactose . Pure culture showed that most of the bacteria tested produce a moderate to large decrease with glucose but only a few do so with galactose; most produced a moderate to little or no pH response with this sugar . This suggested that the smaller decreases in pH seen in plaque in vivo with galactose were largely due to bacterial differences, basically that resident micro-organisms individually have less galactolytic than glucolytic capability . Variance in capability was attributed to differences in membrane transport processes and metabolic pathways normally available to bacteria for galactose and glucose catabolism . In the in vitro experiments, because plaque and sediment can produce base as readily as they can produce acid, the nitrogenous substrates identified earlier as major stimulants of base formation, urea and arginine, were concurrently examined for their attenuating effects on the galactose and glucose pH responses . These showed, consistent with its lesser acidogenicity, that galactose could be countered more readily in its ability to reduce the pH by either of these two base-forming substrates than could glucose . The effects were different with urea and with arginine, urea attenuation occurred sooner and arginine attenuation later in both plaque and sediment . The corresponding acid-base pH profiles for pure cultures were different.(ABSTRACT TRUNCATED AT 250 WORDS)

Cornell Vet, 1992 Oct, 82(4), 379 - 86
Bacteria and yeast on the surface and within non-inflamed hair follicles of skin biopsies from dogs with non-neoplastic dermatoses; Scott DW; Coccoid bacteria and/or yeasts were found in the surface keratin or exudate and/or in the pilar canal of non-inflamed hair follicles upon light microscopic examination of skin biopsies from 191 of 3,387 dogs (5.6%) with non-neoplastic skin disorders . The presence of surface cocci and/or yeast did not appear to suggest a specific dermatosis, nor the existence of a clinically relevant infection in the majority of cases . However, follicular cocci and/or yeast almost always indicated the presence of a clinically relevant infection.

Proc Natl Acad Sci U S A, 1992 Oct 1, 89(19), 8990 - 4
Proposed acquisition of an animal protein domain by bacteria; Bork P et al.; A systematic screen of a protein sequence data base confirms that the fibronectin type III (Fn3) domain is widely distributed among animal proteins and occurs also in several bacterial carbohydrate-splitting enzymes . The motif has yet to be identified in proteins from plants or fungi . All indications are that the bacterial sequences are much too similar to the animal type to be the result of conventional vertical descent . Rather, it is likely that the bacterial units were initially acquired from an animal source and are being spread further by horizontal transfers between distantly related bacteria.

Indian J Gastroenterol, 1992 Oct, 11(4), 168 - 9
Effect of blockade of transdiaphragmatic absorption of bacteria on survival in peritonitis: an experimental study in rats; Lal R et al.; An experimental rat model of established peritonitis was used to test the effect of intraperitoneal injection of platelet rich plasma (PRP) on blood and peritoneal fluid culture positivity and survival rates . Thirty animals divided into two groups of 15 each were studied . The first group served as control while animals in the second group received intraperitoneal injection of PRP . The use of PRP in established . Peritonitis was of no significant benefit.

Curr Microbiol, 1992 Oct, 25(4), 197 - 201
Effects of glycerol on the growth, adhesion, and cellulolytic activity of rumen cellulolytic bacteria and anaerobic fungi; Roger V et al.; The effect of glycerol on the growth, adhesion, and cellulolytic activity of two rumen cellulolytic bacterial species, Ruminococcus flavefaciens and Fibrobacter succinogenes subsp . succinogenes, and of an anaerobic fungal species, Neocallimastix frontalis, was studied . At low concentrations (0.1-1%), glycerol had no effect on the growth, adhesion, and cellulolytic activity of the two bacterial species . However, at a concentration of 5%, it greatly inhibited their growth and cellulolytic activity . Glycerol did not affect the adhesion of bacteria to cellulose . The growth and cellulolytic activity of N . frontalis were inhibited by glycerol, increasingly so at higher concentrations . At a concentration of 5%, glycerol totally inhibited the cellulolytic activity of the fungus . Thus, glycerol can be added to animal feed at low concentrations.

Indian J Lepr, 1992 Oct-Dec, 64(4), 529 - 35
Leprosy-derived chemoautotrophic nocardioform (CAN) bacteria closely resemble, or are identical with, Mycobacterium leprae on mycolate and other lipid profiles; Chakrabarty AN et al.; On the basis of thin layer chromatography and gas-chromatography-mass spectrometric studies, the lipid profiles of all the chemoautotrophic nocardioform (CAN) bacteria derived from human and animal leprosy tissues appear to be identical with each other, and closest to or identical with the most probable profile of M . leprae.

Proc Natl Acad Sci U S A, 1992 Sep 15, 89(18), 8517 - 21
Femtosecond spontaneous-emission studies of reaction centers from photosynthetic bacteria; Du M et al.; Spontaneous emission from reaction centers of photosynthetic bacteria has been recorded with a time resolution of 50 fs . Excitation was made directly into both the special-pair band (850 nm) and the Qx band of bacteriochlorophylls (608 nm) . Rhodobacter sphaeroides R26, Rhodobacter capsulatus wild type, and four mutants of Rb . capsulatus were studied . In all cases the fluorescence decay was not single exponential and was well fit as a sum of two exponential decay components . The short components are in excellent agreement with the single component detected by measurements of stimulated emission . The origin of the nonexponential decay is discussed in terms of heterogeneity, the kinetic scheme, and the possibility of slow vibrational relaxation.

FEMS Microbiol Lett, 1992 Sep 15, 75(2-3), 231 - 4
The mechanism of inhibition by EDTA and EGTA of methanol oxidation by methylotrophic bacteria; Chan HT et al.; Ethyleneglycol (aminoethylether) tetra-acetic acid (EGTA) was shown to be a potent competitive inhibitor of electron transfer between methanol dehydrogenase (MDH) and its electron acceptor cytochrome cL . Addition of Ca2+ ions relieved the inhibition by removal of the inhibitory EGTA . Removal of EGTA by gel filtration completely relieved the inhibition . EGTA did not remove the tightly bound Ca2+ present in the MDH . Indo-1, a fluorescent analogue of EGTA, bound tightly to MDH in a 1:1 ratio but not to cytochrome cL; binding was prevented by EGTA . It was concluded that EGTA inhibits methanol oxidation by binding to lysyl or arginyl residues on MDH thus preventing docking with cytochrome cL.

J Nutr, 1992 Sep, 122(9), 1875 - 83
Consumption of milk from cows immunized with intestinal bacteria influences age-related changes in immune competence in mice; Ishida A et al.; Milk was obtained from nonimmunized cows and cows immunized with a mixture of various human gut bacteria . Each milk was administered orally to 2-mo-old C57BL/6 mice at a dose of 150 g.kg-1.d-1 for either 6 or 16 mo . The study group had fewer enteric bacteria and a lower concentration of the serum antibodies against enteric bacteria compared with the control group at 8 and 18 mo of age . Furthermore, the study group at 18 mo old had a higher redirected cytotoxicity of intestinal intraepithelial lymphocytes, a higher proliferative response of mesenteric lymph nodes cells against mitogenic or alloantigenic stimulation and a greater ability of the spleen cells to produce anti-sheep erythrocytes IgG antibody after systemic immunization with sheep erythrocytes . A lower level of autoantibodies was observed at 8 mo and 18 mo of age in the study group compared with the control group . These results suggest that the senescence of the murine immune system may be delayed by consumption of milk from immunized cows.

Gene, 1992 Sep 1, 118(1), 145 - 6
An improved suicide vector for construction of chromosomal insertion mutations in bacteria; Penfold RJ et al.; We have constructed an R6K-based suicide vector (pJP5603) that requires a trans supply of the pir-encoded pi protein of plasmid R6K for replication . Therefore, efficient plasmid suicide results upon transfer to bacteria not harbouring pir . The 3.1-kb vector encodes kanamycin resistance and is mobilizable . When used in conjunction with a JM109 strain carrying pir, it has nine unique restriction sites available for alpha-complementation cloning . Vector functionality was demonstrated in Rhodobacter sphaeroides.

Clin Exp Allergy, 1992 Sep, 22(9), 863 - 6
Autologous bacteria induce chemotaxis of peripheral blood mononuclear cells (MNC) from non-atopic asthmatics; Zak-Nejmark T et al.; The chemotactic response of peripheral blood MNC from healthy subjects and non-atopic asthmatics against the respective pathogen isolated and cultured from sputum of individual patients was investigated . We found that the wide range of concentrations of autologous bacteria induced chemotaxis of MNC from asthmatics but showed no influence on MNC from healthy subjects . This finding might explain the mechanism of lymphocyte accumulation in the lungs of non-atopic asthmatics.

Poult Sci, 1992 Sep, 71(9), 1480 - 5
Evidence that bacteria are not causative agents of stunting syndrome in poults; Sell JL et al.; Two experiments were conducted to determine the effect of removing bacteria, including long segmented filamentous organisms (LSFO), from inoculum known to induce stunting syndrome (SS) in poults . Experiment 1 consisted of two identically designed trials . In each trial, each of four treatments was assigned to an isolator . Three treatments consisted of dosing, by crop intubation, groups of 1-day-old poults with unfiltered SS inoculum or filtrate of inoculum passed through .45- or .20-micron microfilters . Uninoculated poults were dosed with inoculum carrier, saline . Experiment 2 was done in battery facilities . Three rooms were used and each room housed one of three treatment groups . Triplicate pens of 10 poults each within each room were dosed by crop intubation with saline (uninoculated), unfiltered inoculum, or filtrate from .20-micron filtration . As compared with uninoculated poults, weight gain through 7 days was reduced 20% (P less than .05) by unfiltered and filtered inocula in both experiments . Jejunal maltase activity also was decreased (P less than .01) by unfiltered and filtered inocula . Feed efficiency (FE) was not determined in Experiment 1, but in Experiment 2, FE from 1 to 14 days of age was impaired by inoculum, irrespective of filtration . This effect was not evident during the 14- to 20-day period . The observation that the adverse effects of giving filtered inoculum to poults were the same as those caused by unfiltered inoculum indicated that bacteria, including LSFO, were not primary causative agents of the SS experimentally induced in poults.

J Clin Pathol, 1992 Sep, 45(9), 802 - 5
Possibility of separating toxins from bacteria associated with sudden infant death syndrome using anion exchange chromatography; Drucker DB et al.; AIMS: To develop techniques for the characterisation of toxins elaborated by a strain of Escherichia coli associated with sudden infant death syndrome (SIDS) . METHODS: E coli SIDS 04, isolated from the nasopharynx of a case of SIDS, was studied . Cell-free toxin preparations were standardised, their protein measured, and analytical separation of proteins achieved using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) . Acetone precipitation of proteins was required prior to Coomassie blue staining of bands . Preparative separation was achieved on an anion exchange column using a programmed concentration gradient of NaCl in TRIS buffer . Fractions were tested individually or pooled for presence of lethal toxin including endotoxin . Lethal toxin was detected with the chick embryo test system . Endotoxin was measured using a chromogenic modification of the Limulus amoebocyte assay . RESULTS: Twenty one peaks were detected by chromatography . Ten individual, or pooled, fractions were assayed for endotoxin which ranged from 27-33 pg/ml . Much greater variation was found when the same fractions were assayed in chick embryos . E coli fractions varied considerably in lethal toxicity, from 0/10 to 10/10 chick embryos killed/tested . Certain E coli fractions tested individually (lethality four out of 10 to eight out of 10) proved more lethal (10 out of 10) if pooled prior to testing . CONCLUSIONS: In E coli infection associated with SIDS relatively low concentrations of extracellular protein are lethally toxigenic for the chick embryo model of SIDS . These proteins can be separated analytically by SDS-PAGE and preparatively by anion exchange chromatography . Toxicity of individual fractions is not correlated with endotoxin concentrations in samples tested.

J Appl Bacteriol, 1992 Sep, 73(3), 263 - 8
Coliform bacteria from aquatic sources in Fiji; Roberts S; Coliform bacteria were abundant in water and bivalve molluscs in the rivers and present to a lesser extent in the coastal areas of Fiji . The rivers fed by treated sewage were highly polluted . There was a noticeable increase in concentration of coliforms in bivalve molluscs . It was also found that these bacteria could survive and grow in river water and seawater over a 5-d period, and had a rapid growth rate in nutrient broth under ideal laboratory conditions . They were characterized by the API 20E identification system.

J Periodontol, 1992 Sep, 63(9), 736 - 42
Inhibition of bone DNA and collagen production by surface-associated material from bacteria implicated in the pathology of periodontal disease; Meghji S et al.; Gentle extraction of oral bacteria implicated in the pathogenesis of periodontal disease, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, or Eikenella corrodens, with saline removes the extracellular components while leaving the bacteria intact . This readily-solubilized surface-associated material (SAM) has been demonstrated to significantly inhibit DNA and collagen synthesis by murine calvaria at concentrations as low as 10 ng/ml . DNA and collagen synthesis in isolated calvarial osteoblasts were also inhibited by these SAM preparations with similar dose responses . The inhibitory effect of these bacterial expolymers was blocked by 1 microM indomethacin . The potent inhibitory actions on bone synthesis of the SAM from these bacteria may contribute to the alveolar bone loss found in patients with periodontal disease.

Sci Total Environ, 1992 Aug 12, 123-124, 361 - 75
Evidence of reduced poly-B-hydroxybutyrate biosynthesis in free-living nitrogen-fixing bacteria, Azotobacter chroococcum, following acquired resistance to the fungicide captan; Miclaus N et al.; Some biological activities of Azotobacter chroococcum, strain Azcap 1, (spontaneous mutant, captan resistant up to 300 micrograms/ml) were assayed on RM medium with and without the presence of the fungicide . Comparisons were also carried out with Az . chroococcum sensitive strains Azwt, Azcan 10 and 14 . The hydrolysis of captan, incorporated in agar plates of RM at 100 micrograms/ml, was rapid, since on 4-day plates, no effect was found on the strain Azwt, while on freshly prepared ones its growth was completely blocked . As for Azcap 1, grown on RM only, the behaviour was similar to that of sensitive strains, whereas when grown on captan the results of experiments showed: (i) a lag of approximately 12 h to reach the maximum nitrogen-fixing activity; (ii) delay of 12-24 h in the full consumption of glucose present in the medium, although the invertase activity did not present differences; (iii) high ATP culture content during the 50 h of the experiment; (iv) approximately 6-10-fold lower production of PHB (poly-B-hydroxybutyrate); (v) lack of typical encystment phase, for the tested 96 h and reduced viability in developing colonies on agar RM medium . In contrast, when captan was added to cultural medium at sublethal concentration, 50 micrograms/ml for sensitive strain Azwt and 200 micrograms/ml for Azcap 1, the amount of glutathione produced (to remove the fungicide toxicity) was several times higher for the former.

J Bacteriol, 1992 Aug, 174(16), 5371 - 81
Multiple repetitive elements and organization of the lux operons of luminescent terrestrial bacteria; Meighen EA et al.; The complete nucleotide sequences of the luxA to luxE genes, as well as the flanking regions, were determined for the lux operons of two Xenorhabdus luminescens strains isolated from insects and humans . The nucleotide sequences of the corresponding lux genes (luxCDABE) were 85 to 90% identical but completely diverged 350 bp upstream of the first lux gene (luxC) and immediately downstream of the last lux gene (luxE) . These results show that the luxG gene found immediately downstream of luxE in luminescent marine bacteria is missing at this location in terrestrial bacteria and raise the possibility that the lux operons are at different positions in the genomes of the X . luminescens strains . Four enteric repetitive intergenic consensus (ERIC) or intergenic repetitive unit (IRU) sequences of 126 bp were identified in the 7.7-kbp DNA fragment from the X.luminescens strain isolated from humans, providing the first example of multiple ERIC structures in the same operon including two ERIC structures at the same site . Only a single ERIC structure between luxB and luxE is present in the 7-kbp lux DNA from insects . Analysis of the genomic DNAs from five X . luminescens strains or isolates by polymerase chain reaction has demonstrated that an ERIC structure is between luxB and luxE in all of the strains, whereas only the strains isolated from humans had an ERIC structure between luxD and luxA . The results indicate that there has been insertion and/or deletion of multiple 126-bp repetitive elements in the lux operons of X.luminescens during evolution.

Infect Immun, 1992 Aug, 60(8), 3468 - 71
Purification and immunological studies of the cross-reaction between the 65-kilodalton gonococcal parietal lectin and an antigen common to a wide range of bacteria; Benkirane R et al.; The 65-kDa gonococcal parietal lectin (GPL) has been purified and found to have a lectinlike activity exhibiting both structural and immunological similarities to the common antigen family . Ultrastructural localization of GPL was done by using anti-GPL monoclonal antibodies: GPL is a major component of the outer membrane and is also present in blebs formed by gonococci.

J Cell Biol, 1992 Aug, 118(4), 841 - 58
In vitro and in vivo characterization of four fibroblast tropomyosins produced in bacteria: TM-2, TM-3, TM-5a, and TM-5b are co-localized in interphase fibroblasts; Pittenger MF et al.; Most cell types express several tropomyosin isoforms, the individual functions of which are poorly understood . In rat fibroblasts there are at least six isoforms; TM-1, TM-2, TM-3, TM-4, TM-5a, and TM-5b . TM-1 is the product of the beta gene . TM-4 is produced from the TM-4 gene, and TMs 2, 3, 5a, and 5b are the products of the alpha gene . To begin to study the localization and function of the isoforms in fibroblasts, cDNAs for TM isoforms 2, 3, 5a, and 5b were placed into bacterial expression vectors and used to produce TM isoforms . The bacterially produced TMs were determined to be full length by sequencing the amino- and carboxy termini . These TMs were found to bind to F-actin in vitro, with properties similar to that of skeletal muscle TM . In addition, competition experiments demonstrated that TM-5b was better than TM-5a in displacing other TM isoforms from F-actin in vitro . To investigate the intracellular localization of these fibroblast isoforms, each was derivatized with a fluorescent chromophore and microinjected into rat fibroblasts . TM-2, TM-3, TM-5a, and TM-5b were each found to associate along actin filaments . There was no preferred cellular location or subset of actin filaments for these isoforms . Furthermore, co-injection of two isoforms labeled with different fluorochromes showed identical staining . At the level of the light microscope, these isoforms from the alpha gene do not appear to achieve different functions by binding to particular subsets of actin filaments or locations in cells . Some alternative possibilities are discussed . The results show that bacterially produced TMs can be used to study in vitro and in vivo properties of the isoforms.

Int J Immunopharmacol, 1992 Aug, 14(6), 953 - 61
Effect of apocynin on the induction of ulcerative lesions in rat skin injected with tubercle bacteria; Hart BA et al.; Apocynin is an effective and selective inhibitor of the neutrophil oxidative burst in vitro . Other neutrophil functions, tested in vitro, such as chemotaxis, exocytosis, phagocytosis and intracellular killing of bacteria are unaffected by apocynin . These properties make apocynin a potential anti-inflammatory agent in vivo . This was tested in WAG/Rij rats, injected intracutaneously with tubercle bacteria in oil (complete Freund's adjuvant) . We show here that continuous administration of apocynin via the drinking water prevents the formation of ulcerative lesions in the inflamed skin . No effects on humoral and cellular immunity were observed after treatment with apocynin (between 1 and 100 micrograms/ml drinking water) measuring serum antibodies and delayed-type hypersensitivity, respectively.

Cesk Epidemiol Mikrobiol Imunol, 1992 Aug, 41(3), 145 - 50
{Identification of enteric bacteria using the ENTEROtest 1 and 2 and the ENTERO-Rapid systems}; Sedlacek I et al.; The identification efficacy of two systems, ENTEROtest 1 & 2 and ENTERO-Rapid (fy . Lachema a . c., Brno), was compared . A total 123 well known strains of enteric bacteria were tested . The ENTEROtest 1 & 2 system correctly identified 87.0% tested strains to the species level, the ENTERO-Rapid system correctly identified 76.4% of these strains.

Biol Chem Hoppe Seyler, 1992 Aug, 373(8), 715 - 21
Isolation of a high-molecular mass glycoprotein from culture supernatant of an arthritogenic strain of the bacteria Erysipelothrix rhusiopathiae reacting with "inductive" monoclonal antibodies derived from rats with erysipelas polyarthritis; Meier B et al.; A glycoprotein exhibiting a relative molecular mass of about 1000 kDa was purified to homogeneity from culture supernatant of arthritogenic bacteria (Erysipelothrix rhusiopathiae, strain T28) by ultrafiltration, ammonium sulfate precipitation, molecular mass exclusion, and ion exchange chromatography . Fractions obtained were analysed for their antigenic content by an enzyme linked immunosorbent assay (ELISA) using rabbit immune serum raised against this strain of Erysipelothrix rhusiopathiae . Distinct monoclonal antibodies obtained from rats suffering from erysipelas polyarthritis display a unique property by inducing very efficiently protective and regulatory mechanisms while being unable to generate classical "passive immunity" . These "inductive" monoclonal antibodies recognize most likely linear epitopes on the purified glycoprotein . This makes it a prime source for analysing the target structure of these in vivo "inductive" antibodies.

Oral Microbiol Immunol, 1992 Aug, 7(4), 225 - 9
The establishment of human T cell lines reactive with specific periodontal bacteria; Ishii T et al.; Human T cell lines (TCLs) were obtained by stimulation of peripheral blood mononuclear cells (PBMCs) with the 2 periodontopathic bacteria, Porphyromonas gingivalis FDC-381 and Fusobacterium nucleatum FDC-263 . After the first round of stimulation and rest, the cells responded specifically to the bacteria originally used to establish each line . Throughout the culture period, the responsiveness of each of the TCLs to their specific bacteria increased . Phenotypic analysis of the TCLs revealed heterogeneity of cell types . In both TCLs approximately 80% of the cells were T cells, all of which bore the alpha beta T cell receptor . The P . gingivalis-reactive TCL (PG-TCL) showed approximately equal proportions of CD4+ and CD8+ cells, whereas the F . nucleatum-reactive TCL (FN-TCL) was predominantly CD4+ . The expression of CD25, HLA-DR, CD45RA and CD29 on these CD4+ cells varied throughout the culture period of 45 days . These results demonstrate that it is possible to establish long-term T cell lines reacting to specific periodontopathic bacteria.

Arch Oral Biol, 1992 Aug, 37(8), 667 - 70
Three types of binding by Porphyromonas gingivalis and oral bacteria to fibronectin, buccal epithelial cells and erythrocytes; Isogai E et al.; This study showed that the interaction of oral bacteria with fibronectin differed with the type of organism examined . Significant binding of fibronectin was found with Porphyromonas gingivalis non-fimbriated (F-) strain in comparison with the fimbriated strain (F+) . However, the F+ strain adhered to buccal epithelial cells in significantly larger numbers than the F- strain . Fibronectin binding and epithelial cell adherence were not associated with haemagglutinating activity . These assays clearly define at least three distinct types of binding by oral bacteria: to fibronectin, buccal epithelial cells and erythrocytes.

Anal Biochem, 1992 Aug 1, 204(2), 292 - 5
Use of diethyldithiocarbamate for quantitative determination of tellurite uptake by bacteria; Turner RJ et al.; We have developed a simple method for the quantitative determination of tellurite in biological media . This assay is suitable for studying tellurite uptake in bacteria and overcomes the problems of older techniques which are time consuming and labor intensive . In earlier protocols diethyldithiocarbamate was reacted with tellurite and the resulting complex was extracted into organic solvents before spectrophotometric determination . In this study, diethyldithiocarbamate was incubated with tellurite at neutral pH to form a yellow colloidal solution . The absorbance of the aqueous yellow sol was used to determine tellurite concentrations in the range of 1 to 50 micrograms/ml (4 to 200 microM) without the need for solvent extraction.

Arch Oral Biol, 1992 Aug, 37(8), 637 - 44
Anti-proliferative and cytotoxic activity of surface-associated material from periodontopathogenic bacteria; Meghji S et al.; The easily solubilized surface-associated material from three bacterial species associated with periodontal diseases, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Eikenella corrodens, produced dose-dependent inhibition of thymidine incorporation by human fibroblasts, the human monocytic cell line U937 and guinea pig epidermal cells . In contrast, lipopolysaccharides from A . actinomycetemcomitans and P . gingivalis were either inactive or substantially less active over the dose range tested . One of the constituents of surface-associated material from a 'non-leucotoxic' strain of A . actinomycetemcomitans was highly cytotoxic to human peripheral blood polymorphonuclear cells, with 50% killing from less than 1 ng/ml . A constituent of the surface-associated material from P . gingivalis was approximately one log order less active . The lipopolysaccharides from these bacteria were at least three log orders less active in neutrophil killing . These findings add weight to the hypothesis that easily solubilized exopolymers from periodontopathogens play a major part in the pathology of periodontal diseases.

Biochim Biophys Acta, 1992 Jul 17, 1101(2), 154 - 6
The photosystem I-like P840-reaction center of green S-bacteria is a homodimer; Buttner M et al.; An operon encoding the P840 reaction center of Chlorobium limicola f.sp.thiosulfatophilum has been cloned and sequenced . It contains two structural genes coding for proteins of 730 and 232 amino acids . The first protein resembles the large subunits of the Photosystem I (PS I) reaction center . Putative binding elements for the primary donor, P840 in Chlorobium and P700 in PS I and for the acceptors A(o), A(1) and FeS-center X are conserved . The second protein is related to the PS I subunit carrying the FeS-centers A and B . Since all our efforts to find a gene for a second, large subunit failed, the P840 reaction center probably is homodimeric.

Gene, 1992 Jul 15, 116(2), 165 - 72
Expression of a gene encoding a scorpion insectotoxin peptide in yeast, bacteria and plants; Pang SZ et al.; The nucleotide sequence encoding the scorpion insectotoxin I5A was chemically synthesized and expressed in yeast, bacteria and tobacco . The I5A peptides produced in these organisms were purified using an immunoaffinity chromatography procedure . I5A produced using the bacterial secretion system was efficiently secreted and released into the culture medium . In contrast, only a trace amount of I5A was detected in bacterial cytosols when expressed from a direct expression vector, suggesting that I5A was unstable in bacterial cells . I5A secreted from yeast using an alpha-factor signal sequence was shown to have an N-terminal (Glu-Ala)2 extension, indicating incomplete processing of the secreted peptide by dipeptidyl aminopeptidase A . In tobacco, a nonsecreted form of the protein was produced . No measurable insect toxicity was observed when insect larvae were assayed, regardless of whether I5A was produced in yeast, bacteria or tobacco . The lack of toxicity is almost certainly the result of improper folding due to incorrect disulfide bond formation . The inability to produce a biologically active peptide must be overcome before scorpion toxins might be used for the genetic engineering of plants for insect resistance . The yeast and bacterial expression systems described here may be useful for further studies on the problem of expressing a biologically active peptide.

Plasmid, 1992 Jul, 28(1), 46 - 60
Selection of Dictyostelium discoideum transformants and analysis of vector maintenance using live bacteria resistant to G418; Hughes JE et al.; A protocol that allows the rapid isolation and growth of large numbers of independent G418-resistant Dictyostelium discoideum transformant colonies on the surface of agar media with live bacteria was developed . Transformants grown under these conditions form normal fruiting bodies . Discovery that aggregation of nontransformants was inhibited at a nonselective level of G418 (25 to 35 micrograms/ml) led to the development of a vector maintenance assay . Using this assay we examined the stability of recombinant plasmids derived from the D . discoideum native plasmids Ddp1 and Ddp2 . We conclude that the origin of replication of plasmid Ddp1 does not alone confer stable maintenance and thus, Ddp1 must bear additional sequences required for its own maintenance . Analysis of the maintenance of vectors derived from Ddp2 showed that autonomously replicating shuttle vectors that contained bacterial plasmid DNA and from which one element of the Ddp2 inverted repeat was removed were much less stable than vectors that contained a complete inverted repeat or that did not carry a bacterial plasmid . Sequences between the 3' end of the rep gene and the inverted repeat appear to play a role in plasmid maintenance . An intact rep gene and one copy of the inverted repeat element were required for extrachromosomal replication . Maintenance of extrachromosomal vectors was found to be strain dependent . Four traits distinguishing integrating vectors from those capable of autonomous replication were identified.

Mikrobiologiia, 1992 Jul-Aug, 61(4), 692 - 6
{Conjugative transfer of plasmid DNA between bacteria in soil}; Lukin SA et al.; Conjugative transfer of plasmid RP4 between populations of azospirilla and between Escherichia coli and Azospirillum brasilense in nonsterile soil has been investigated . The process of genetic exchange was realized at the early stages of interpopulational interactions, further on the process intensity was obviously rather low . Population dynamics of azospirilla transconjugates in soil depends on the presence or the absence of additional food substrate.

Genetika, 1992 Jul, 28(7), 46 - 53
{Mutagenic effect on Escherichia coli bacteria of 8-hydroxy-2'-deoxyguanosine--a DNA base damage product induced by oxygen radicals and ionizing radiation}; Bruskov VI et al.; The effect of 8-oxo-2'-deoxyguanosine (8-oxo-dG) (8-hydroxydeoxyguanosine)--a DNA base damage product induced by oxygen radicals and irradiation on survival and mutagenesis in Escherichia coli strains C-600 and P-687 was investigated . Survival and mutagenesis curves, in dependence of 8-oxo-dG concentrations in the medium, ranging from 0.2 through 10 mM, were obtained . Bacterial survival at all 8-oxo-dG concentrations tested was shown to be no lesser than in the control . The mutagenic effect of 8-oxo-dG was tested by frequency of reversions in the absence of leucine and threonine . A non-linear dependence of mutagenesis on the concentration was observed . Linear increase in the amount of revertants took place at concentrations of 8-oxo-dG lower than 1 mM, and being kept constant at higher concentrations . Induction of SOS repair under the action of 8-oxo-dG in E . coli PQ37 strain was estimated according to alteration of activity of beta-galactosidase in the SOS chromotest . Weak induction of the SOS response was observed within the wide range of 8-oxo-dG concentration values, which points to a lack of genotoxicity and independence of mutagenesis on SOS repair.

Appl Environ Microbiol, 1992 Jul, 58(7), 2302 - 7
Localization of methanol dehydrogenase in two strains of methylotrophic bacteria detected by immunogold labeling; Fassel TA et al.; Antibodies to methanol dehydrogenase purified from Methylobacterium sp . strain AM1 and Methylomonas sp . strain A4 were raised . The antibody preparations were used in indirect immunogold labeling studies . With this approach, methanol dehydrogenase was found to be preferentially localized to the periplasmic region of the methylotroph Methylobacterium sp . strain AM1 and to the intracytoplasmic membrane of the methanotroph Methylomonas sp . strain A4 . Antibody cross-reactivity to other methylotrophic bacteria was detected.

Mol Gen Genet, 1992 Jun, 233(3), 331 - 6
Mutagenesis after exposure of bacteria to ultraviolet light and delayed photoreversal; Bridges BA; The induction of mutations by ultraviolet light and delayed photoreversal in bacteria defective for SOS mutagenesis is discussed in terms of two models: the two-step misincorporation and bypass model, and the model involving simple deamination of cytosine-containing dimers . In phage S13 the latter appears to be the predominant mechanism . In Escherichia coli there is little evidence that the simple deamination mechanism is of any significance except in ung strains lacking uracil glycosylase where uracils left after photoreversal are not removed . Deamination might, however, occur during the operation of translesion synthesis via the two-step model and if it did, subsequent photoreversal would lead to the "mutation" being extended from one to both strands by uracil glycosylase repair rather than being removed.

Mol Endocrinol, 1992 Jun, 6(6), 861 - 9
Structural requirements for high affinity ligand binding by estrogen receptors: a comparative analysis of truncated and full length estrogen receptors expressed in bacteria, yeast, and mammalian cells; Wooge CH et al.; In order to better understand the structural requirements for effective high affinity binding of estrogens and antiestrogens by the human estrogen receptor (ER), a comparative study was undertaken in which we examined: 1) native ER from the MCF-7 ER-positive human breast cancer cell line; 2) full length ER expressed in yeast; 3) the ER hormone binding domain (amino acid residues 302-595) expressed in yeast; 4) a bacterially expressed protein A fusion product encoding a truncated ER (amino acid residues 240-595); and 5) a synthetic peptide encompassing amino acids 510-551 of the ER . The binding parameters studied included affinity, kinetics, structural specificity for ligands, and stability . Full length ER expressed in yeast was very similar to the MCF-7 ER in its affinity {dissociation constant (Kd), 0.35 +/- 0.05 nM}, dissociation rate (t1/2, 3-4 h at 25 C), and structural specificity for both reversible and covalently attaching affinity ligands . While the truncated ER expressed in yeast was similar to MCF-7 ER in its specificity of ligand binding, it showed a slightly reduced affinity for estradiol (Kd, 1.00 +/- 0.17 nM) . The bacterially expressed ER also had a lower affinity for estradiol (Kd, 1.49 +/- 0.16 nM), which may be due in part to an increase in the dissociation rate (t1/2, 0.5 h at 25 C) . The attachment of covalent affinity ligands and structural specificity for a variety of reversible ligands was comparable in the bacterially expressed ER to that observed for the receptors expressed in MCF-7 cells and yeast.(ABSTRACT TRUNCATED AT 250 WORDS)

Biotechnology (N Y), 1992 Jun, 10(6), 661 - 6
Runaway-replication plasmids as tools to produce large quantities of proteins from cloned genes in bacteria; Nordstrom K et al.; Here we review the properties and uses of runaway-replication vectors, a class of versatile plasmids discovered and developed in Escherichia coli . They are based on the IncFII plasmid, R1, in which an antisense RNA (CopA RNA) negatively controls the formation of a protein that is rate-limiting for replication . The copy number of the plasmid is determined by the balance between the rates of formation of CopA RNA and RepA mRNA . A small increase in the rate of formation of the latter drastically reduces the rate of formation of CopA RNA due to convergent transcription, which may lead to a total loss of copy number control (runaway replication), resulting in massive DNA amplification, and plasmid copy numbers up to 1000 per genome . Since this amplification occurs in the presence of protein synthesis, the protein that is encoded by a cloned gene can also be amplified, and may constitute 10-50% of the total protein.

Trends Biochem Sci, 1992 Jun, 17(6), 207 - 11
Death and transfiguration among bacteria; Higgins NP; When bacteria are placed in sub-optimal environments, they can respond by increasing the frequency of mutants created by base substitution, frame-shift and transposition mutations . Also, during periods of restrictive growth, 'dead' bacterial cells may transfer genetic material to neighboring colony-forming cells . This can be beneficial, resulting in a heterogeneous population that may exhibit differentiation and even produce killer cells . These discoveries reveal several conundrums about the control of an organism over mutations and the supposed randomness of genetic variation.

J Dairy Sci, 1992 May, 75(5), 1305 - 12
Ventilation system to minimize airborne bacteria, dust, humidity, and ammonia in calf nurseries; Hillman P et al.; We installed a ventilation system that minimizes airborne bacteria, dust, humidity, and ammonia levels; conserves animal heat during the winter months by precise control of the amount of fresh air admitted to the calf nursery; and prevents cross transfer of airborne pathogens between neighboring calves by providing uniform air distribution throughout the calf nursery . Because of the effectiveness of air filtration and uniform air distribution within the nurseries, respiratory problems of calves were reduced greatly . Airborne dust and bacteria as small as .5 mu were filtered from the air.

Anal Biochem, 1992 May 1, 202(2), 293 - 8
New vectors for high level expression of recombinant proteins in bacteria; Hakes DJ et al.; A system has been developed for synthesis and rapid purification of recombinant polypeptides expressed in frame with glutathione S-transferase (D . B . Smith and K . S . Johnson, 1988, Gene 67, 31-40) . Expressed fusion proteins are purified from bacterial extracts by glutathione-agarose affinity chromatography . A thrombin protease cleavage site allowed for proteolysis of the fusion protein . We reported the construction of the vector pGEX-KG (K . Guan and J . E . Dixon, 1991, Anal . Biochem . 192, 262-267) which has a glycine-rich "kinker" immediately after the thrombin cleavage site . This kinker dramatically improved the thrombin cleavage efficiency of several fusion proteins . One potential drawback of expressing proteins in this vector is that, following proteolytic cleavage, unrelated amino acids from the vector remain at the amino terminus of the released protein . These extensions could affect enzymatic activity or protein structure . We have constructed two new vectors, pGEX-KT and pGEX-KN, which have the glycine kinker placed N-terminal to the thrombin cleavage site in order to minimize the unrelated amino acids associated with the cleaved protein . The change in location of the kinker had no effect on the increased thrombin cleavage efficiency . A strategy combining the kinker in the vector pGEX-KN with polymerase chain reaction has also been developed to express fusion proteins which when cleaved with thrombin released a protein having no amino terminal extensions of any kind.

Jpn J Pharmacol, 1992 May, 59(1), 1 - 5
The role of intestinal bacteria in the transformation of sodium picosulfate; Kim DH et al.; Sodium picosulfate, a laxative, was biotransformed to 4,4'-dihydroxydiphenyl-(2 pyridyl)-methane by intestinal flora that produced a novel sulfotransferase (not sulfatase) . The biotransformation was activated by adding phenolic compounds such as phenol, acetaminophen and flavonoids . The enzyme activity related to this biotransformation was the highest in the contents of the caecum region of the intestine . The enzyme activity was 3.0 mumole/hr/g wet feces in humans and 0.75 in rats (pH 8.0) . The optimal pH was 9.0.

Zh Evol Biokhim Fiziol, 1992 May-Jun, 28(3), 287 - 97
{The evolutionary changes in the amino acid sequences and properties of the ATP-synthase in chloroplasts, mitochondria and bacteria}; Ivashchenko AT et al.; Studies have been made on ATPase from chloroplasts, cyanobacteria and mitochondria of higher plants and animals . No intraspecies and interspecies variability of chloroplast and mitochondrial ATPase was found with respect to pH optimum of the activity, to specificity to cations as substrate components, to sensitivity to stimulating and inhibiting anions and ethanol, to optimal stimulating ethanol concentration . Intergenus variation of these properties of ATPase from chloroplasts, plant mitochondria, and cyanobacteria was revealed . Analysis of homology of the amino acid sequence in ATP-synthase subunits showed that ATP-synthase genes in chloroplast DNA originate from cyanobacterial genome, whereas ATP-synthase genes in plant and animal mitochondria-from genome of Rhodospirillum rubrum or closely related species . It was established that no recombination between the genetic material of chloroplasts and mitochondria took place during evolution.

Vet Med (Praha), 1992 May-Jun, 37(5-6), 293 - 305
{Changes in the amino acid levels in hydrolysates of bacteria adhering to the rumen in sheep during feeding with high and low nitrogen diets}; Legath J; The effects of low and high nitrogen diets on amino acid levels were studied in hydrolyzates of ruminal bacteria adhered to four topographically different anatomic parts of the ruminal wall (dorsal, ventral and caudal parts as well as reticulum) in 18 sheep + of the Slovak Merino breed divided into three experimental groups . The epimural bacteria of the dorsal and ventral parts of the ovine rumen revealed the most sensitive reaction to the varying amounts of nitrogen ingested with the diet . In hydrolyzates of ruminal bacteria adhered to the dorsal and ventral epithelium, 15 and 14 amino acids were changing (Figs . 1, 2) . In hydrolyzates of epimural bacteria, a sensitive reaction was observed in the following amino acids: alanine, histidine, thyroxin, arginine and proline (Tabs . I-IV) . In all topographical and anatomical parts of the rumen, both alanine and histidine levels in hydrolyzates of epimural ruminal bacteria significantly increased with the diet with high-nitrogen content fed, but was falling in sheep fed with low-nitrogen diet . Changes in alanine concentrations may be explained by the fact that alanine forms a part of the mechanism for short-time storage of ammonia in bacterial cells (Bartos, 1987) . The fact that alanine is in its lack deaminated to pyruvate (Havassy, 1976) is explained by significant fall in alanine contained in hydrolyzates of bacterial proteins when fed low nitrogen diets . Significant fall in alanine in shortage of amino acid bound nitrogen can be explained by the fact that under these conditions, the alanine skeleton is being incorporated in to 80% of amino acids synthetized de novo by ruminal bacteria (Syvaoja and Kreula, 1980) . When sheep flock was fed the high-nitrogen diet, thyroxin and proline levels were significantly reduced in hydrolyzates of epimural bacteria from all parts of the rumen, while low-nitrogen diet significantly increased the concentrations of both given amino acids in comparison with the control . Bartos (1987) gives in his study the table containing weight representation of different amino acids in proteins of bacteria of the ruminal content compiled on the basis of data of several authors . These data principally correspond to the results of our measurements in hydrolyzates of epimural bacteria . The highest weight representation of amino acids in hydrolyzates of epimural bacteria was found for glutamic acid, aspartic acid and arginine, while the lowest ones were detected for thyroxin, proline and phenylalanine.(ABSTRACT TRUNCATED AT 400 WORDS)

Mol Biol (Mosk), 1992 May-Jun, 26(3), 591 - 5
{Pea (Pisum sativum) genes, participating in symbiosis with nitrogen-fixing bacteria . III . Study of the structure of the ENOD12 early nodulin gene for various types of peas using the polymerase chain reaction (PCR)}; Kozik AV et al.; We have determined the length of early noduline gene ENOD12 in various varieties and lines of pea (Pisum sativum) using the polymerase chain reaction (PCR) . It was demonstrated that promoter regions of ENOD12A and ENOD12B genes in line 2150 (Afghanistan) are longer than these in variety "Feltham first" . The disparity is 14 bp . When studying these genes in 7 different lines and varieties of pea it was found that ENOD12A gene is more variable in size than the ENOD12B gene . We showed the possibility to analyze the heritage of ENOD12 gene's alleles by using the PCR method.

J Biol Chem, 1992 Apr 25, 267(12), 8458 - 63
In vitro isoprenylation and membrane association of mouse rod photoreceptor cGMP phosphodiesterase alpha and beta subunits expressed in bacteria; Qin N et al.; We investigated the specificity of CAAX box-related isoprenylation of rod photoreceptor cGMP phosphodiesterase (PDE) subunits expressed in bacteria and the consequences of this modification on rod disk membrane association . Full-length cDNA sequences of the alpha and beta subunits of mouse PDE, inserted into bacterial pET expression vectors, were overexpressed as fusion proteins containing 28 (bMP-alpha) and 26 (bMP-beta) additional amino acid residues at their N termini . Both fusion proteins were overexpressed and stored in inclusion bodies . Purified bMP-alpha and bMP-beta were recognized by bovine PDE-specific polyclonal antibodies, but did not associate with depleted rod disk membranes and were catalytically inactive . Using bovine brain or retina extracts as sources of protein prenyltransferases and tritiated farnesyl- or geranylgeranylpyrophosphate as donors, bMP-alpha (CAAX sequence CCIQ) was exclusively farnesylated, and bMP-beta (CAAX sequence CCIL) was exclusively geranylgeranylated . After isoprenylation, bMP-alpha and bMP-beta each associated with rod photoreceptor outer segment disk membranes under isotonic, but not under hypotonic, conditions . The results indicate that isoprenylated bMP-alpha and bMP-beta each interact independently with membranes and that isoprenylation is the key modification that facilitates membrane association.

Microbiologica, 1992 Apr, 15(2), 205 - 8
Effect of storage upon the toxicity of synfuel process waters to bacteria; Lyon RB et al.; Storage of synfuel process waters at 4 degrees C for 8 years appeared to reduce the toxicity of these waters to indicator bacteria . When these waters were mixed in the amount of 10 percent process waters to 90 percent sewage, heterotrophic bacteria grew which indicate that storage or aeration may improve the treatability of these waters.

Infect Immun, 1992 Apr, 60(4), 1711 - 3
Modulation of a surface antigen of Entamoeba histolytica in response to bacteria; Bhattacharya A et al.; Changes in the cell surface of Entamoeba histolytica, a human intestinal parasite and the causative agent of amebic dysentery, were examined with a monoclonal antibody, 2D7.10, which selectively recognizes carbohydrate epitopes in some axenic amebic strains . While high-level expression of this epitope was observed in axenic amebae, it was either absent or present only in small amounts in xenic amebae . Furthermore, reassociation of the axenic amebae with intestinal flora resulted in loss of the 2D7.10 epitope . Our data suggest that surface antigens of E . histolytica can be modulated in response to bacteria and may provide an explanation for the observed influence of bacteria on amebic virulence.

Oral Microbiol Immunol, 1992 Apr, 7(2), 84 - 8
CD45RA and CD45RO positive CD4 cells in human peripheral blood and periodontal disease tissue before and after stimulation with periodontopathic bacteria; Gemmell E et al.; Flow cytometric analysis was used to examine naive and primed or memory CD4 cells extracted from periodontal lesions compared with cells from peripheral blood of healthy subjects before and after stimulation with the periodontopathic bacteria, Porphyromonas gingivalis and Fusobacterium nucleatum . In peripheral blood, approximately 60% and 40% of CD4 cells were CD45RO+ and CD45RA+ respectively at day 0 . Phytohaemagglutinin (PHA) induced CD45RO expression on almost 100% of CD4 cells . However, P . gingivalis and F . nucleatum stimulation did not cause any significant change in percentage of CD45RO+ CD4 cells except for a loss of antigen at day 6 together with re-expression at day 7, which also occurred on cells cultured in medium only . CD45RA expression on PHA and bacterial-stimulated peripheral blood CD4 cells remained fairly stable for the 10-d culture period . Greater than 90% CD4 cells extracted from healthy or marginal gingivitis (H/MG) and adult periodontitis (AP) lesions were CD45RO+ and this was maintained on AP cells throughout the 6-d culture period, except for a small decrease in the percentage of positive cells induced by P . gingivalis at day 3 . Approximately 9% CD4 cells from H/MG tissue were CD45RA+, but about 22% AP cells expressed this antigen, and this increased again in P . gingivalis- and F . nucleatum-stimulated cultures after 3 d . Therefore, in peripheral blood P . gingivalis and F . nucleatum do not act as nonspecific T-cell mitogens and, in AP cells, these bacteria induce changes in phenotype, supporting previous data that although they may be polyclonal B-cell activators, they activate antigen specific T-cells.

J Exp Anim Sci, 1992 Mar, 35(1), 2 - 15
Changes in rat leukocyte populations in peripheral blood, spleen, lymph nodes, and synovia during Erysipelas bacteria-induced polyarthritis; Ziesenis A et al.; Kinetics of leukocyte subsets were followed for several weeks in rats suffering from polyarthritis induced by experimental infection with erysipelas bacteria (Erysipelothrix rhusiopathiae, serovar 2, strain T28) . A marked leukocytosis was found in peripheral blood, and, with some delay, in the synovia and draining lymph nodes of affected joints . In the lymphoid organs tested considerable blast formation of lymphoid cells with a paucity of polymorphonuclear granulocytes was found, while the latter represented the majority of leukocytes in acutely inflamed joints . Cells isolated from spleen showed only moderate and transient alterations in proportions of subpopulations during the first week after inoculation of erysipelas bacteria . In contrast, cells isolated from synovia of inflamed joints and draining lymph nodes displayed more intense and longer lasting alterations: In arthritic animals, the proportion of MHC class II-positive lymphocytes generally increased and remained elevated at least during the first three weeks of the disease . Spontaneous release of IL-2 from cells isolated up to 20 days post induction of the arthritis indicated a considerable activation of lymphocytes in vivo . Interestingly, with exception of synovia, the relative amount of T-lymphocytes including their major CD4+ and minor CD8+ subsets showed little alteration during the course of the disease . Much more pronounced were the rapidly and the extent the membrane Ig-positive B-lymphocytes increased in the synovia as well as in the lymph nodes . Thus, B-lymphocytes may be of particular relevance for elucidating pathomechanisms of erysipelas polyarthritis.

J Virol, 1992 Mar, 66(3), 1746 - 51
Effect of zinc ions on the biochemical behavior of simian virus 40 small-t antigen expressed in bacteria; Goswami R et al.; The simian virus 40 small-t antigen contains 10 cysteine residues, 6 of which are organized in two CysXCysXXCys clusters . Mutation of individual Cys residues in the two clusters or mutation of specific residues found between these clusters causes pronounced instability of the protein in animal cells . Protein instability correlates with failure of the bacterially expressed mutant proteins to bind zinc ions, an interaction which allows purification of large amounts of small-t antigen in monomeric form.

Biochim Biophys Acta, 1992 Feb 13, 1119(1), 97 - 106
The interaction of methanol dehydrogenase and its electron acceptor, cytochrome cL in methylotrophic bacteria; Cox JM et al.; The interactions of methanol dehydrogenase (MDH, EC1.1.99.8) with its specific electron acceptor cytochrome cL has been investigated in Methylobacterium extorquens and Methylophilus methylotrophus . The MDHs of these two very different methylotrophs have the same alpha 2 beta 2 structure; the interaction of these MDHs with their specific electron acceptor, cytochrome cL, has been studied using a novel assay system . Electrostatic reactions are involved in 'docking' of the two proteins . EDTA inhibits the reaction by a process involving neither metal chelation nor the 'docking' process . Chemical modification studies showed that the two proteins interact by a 'docking' process involving interactions of lysyl residues on MDH and carboxyl residues on cytochrome cL . When 'zero length', two stage cross-linking was done (with proteins from both bacteria), the alpha-subunits of MDH cross-linked with cytochrome cL by way of lysyl groups on MDH and carboxyl groups on the cytochrome . Tuna mitochondrial cytochrome c provided a model for cytochrome cH which is the electron acceptor for cytochrome cL in the 'methanol oxidase' electron transport chain . Tuna cytochrome c was shown to form crosslinked products with carboxyl-modified cytochrome cL . MDH and tuna cytochrome c competed for the same domain on cytochrome cL . It was concluded that MDH reacts with cytochrome cL by an electrostatic reaction which involves carboxyl groups on cytochrome cL and amino groups on the alpha-subunit of MDH . The same domain on cytochrome cL is involved in subsequent 'docking' with its electron acceptor.

Pediatr Infect Dis J, 1992 Feb, 11(2), 105 - 13
Lack of evidence of efficacy of cohorting nursing personnel in a neonatal intensive care unit to prevent contact spread of bacteria: an experimental study; Ehrenkranz NJ et al.; Nurse cohorting was investigated in a modern neonatal intensive care unit (NICU) . During 99 days bacterial infection and colonization rates were determined in 100 infants experimentally assigned cohort or noncohorted care . Colonizing isolate identity was determined by plasmid profile analyses and biotyping in weekly surveillance cultures . Between Days 2 and 7, 3 infections occurred in cohorted infants but none in noncohorted ones . No secondary spread of infection or definitive colonization cluster occurred . The first colonization rate, at any site, was 0.53/patient-week in the noncohorted and 0.3 to 0.4 in the cohorted units (P greater than 0.05) . Colonization ratios with species other than usual skin bacteria in the respiratory tract and with species other than Escherichia coli in the rectum were lower for noncohorted infants . Effective infection control practices in a modern NICU, including alcohol hand antisepsis, should obviate a need for cohorting.

Anal Biochem, 1992 Feb 1, 200(2), 405 - 10
A zymographic assay for detection of hyaluronidase activity on polyacrylamide gels and its application to enzymatic activity found in bacteria; Steiner B et al.; A zymographic assay for the determination of hyaluronidase activity in cell-free extracts on native polyacrylamide gels has been developed . In this assay an agarose replica of the polyacrylamide gel which contains hyaluronic acid and bovine serum albumin (BSA) was used . After an incubation at 37 degrees C to allow transfer and development of enzymatic activity, the hyaluronic acid and BSA were precipitated in the agarose gel with 2 M acetic acid . Areas of enzymatic activity appeared as clear zones in the agarose replica . The assay was sensitive and was used to demonstrate hyaluronidase activity in cell-free extracts from a number of bacterial and mammalian species.

FEMS Microbiol Rev, 1992 Feb, 8(2), 93 - 108
Can the excretion of metabolites by bacteria be manipulated?
Konings WN, Poolman B, Driessen AJ.
Bacteria can release metabolites into the environment by various mechanisms . Excretion may occur by passive diffusion or by the reversal of the uptake process when the internal concentration of the metabolite exceeds the thermodynamic equilibrium level . In other cases, solutes are excreted against the concentration gradient by special extrusion systems . Their mode of energy coupling is different to that of the well-studied group of uptake systems . A thorough understanding of the transport processes will help to improve the excretion of metabolites of commercial interest, allow a more efficient production of metabolites in bulk quantities, and permit their exploitation to establish new markets.

J Anim Sci, 1992 Feb, 70(2), 538 - 46
Effect of asynchronous nitrogen and energy supply on growth of ruminal bacteria in batch culture; Newbold JR et al.; The effects of an asynchronous supply of fixed amounts of N and carbohydrate on bacterial growth were measured in two batch culture experiments . In Exp . 1, aqueous glucose and urea solutions were added at hourly intervals to culture flasks containing strained ruminal liquor and phosphate/bicarbonate buffer . The ratio of urea N to glucose was either constant (Synchrony, 26 mg of N/g of glucose) or increased exponentially over time (Asynchrony, .013 to 48,900 mg of N/g of glucose) . After 12 h, identical quantities of glucose and urea had been added in both treatments . Bacterial population size (estimated from optical density) was greater (P less than .001) from 5 to 8 h of incubation for Synchrony than for Asynchrony, but after 12 h there was no difference (P greater than .1) between treatments . In Exp . 2, large (1 to 1.5 mm) and small (less than .5 mm) corn particles were used as slowly and rapidly degraded energy sources, with soybean meal (1 to 1.5 mm) and a papaic digest of soybean meal as sources of slowly and rapidly degraded N . At incubation times, when the ratio between total starch and N degraded was equal between treatments, bacterial population size was unaffected by the relative rate of N and OM supply . In both experiments, bacterial growth recovered quickly from transient restriction caused by deficits of N.

Protein Expr Purif, 1992 Feb, 3(1), 57 - 64
A new series of trpE vectors that enable high expression of nonfusion proteins in bacteria; Mercy MR et al.; Expression of recombinant proteins in bacteria has facilitated the characterization of many gene products . However, the biochemical characterization of recombinant proteins is limited since the bacterially expressed proteins are often synthesized as fusion polypeptides . The presence of bacterial sequences in fusion proteins further limits the use of these proteins for generating antibodies since the bacterial sequences are also antigenic . We describe two new bacterial expression vectors based on the pATH series of plasmids . These vectors were made by precisely deleting all of the trpE coding sequences found in pATH . The new vectors have enabled us to express eukaryotic genes as nonfusion polypeptides . These altered plasmids can be used to insert any DNA sequence of interest through a multiple cloning site located just 3' of an ATG start codon . Protein expression is still under the control of the trp operon and is carried out at great efficiency when the bacteria are tryptophan deprived . Studies presented here test the expression system with neurofilament subunits, NF-L and NF-H . Large amounts of recombinant nonfusion proteins were produced . Also, a time course of induction shows that the production of the nonfusion proteins was under the control of the trp operon which is readily inducible after tryptophan starvation and addition of indoleacrylic acid . These vectors may be useful for the overexpression of many proteins in a form closely approximating their native state.

Mol Microbiol, 1992 Feb, 6(3), 277 - 82
Control of functional mRNA stability in bacteria: multiple mechanisms of nucleolytic and non-nucleolytic inactivation; Petersen C; Messenger RNA in bacteria may be inactivated by several parallel mechanisms acting independently on different target sites . For any species of mRNA the overall rate of inactivation is determined by the sum of the contributions from the different mechanisms . Transcripts may be inactivated directly by endonucleolytic attack or by processive nucleolytic degradation, which may proceed in the 3'-5' direction and probably also in the 5'-3' direction . Moreover, the functional lifetime of many mRNAs may be determined by processes that are not nucleolytic, such as the binding of translational repressors or the formation of secondary structures which prevent initiation of translation . These non-nucleolytic processes may also determine the chemical stability as chemical degradation frequently appears to be closely coupled to functional inactivation . The relative importance of the different mechanisms in the inactivation of bulk cellular mRNA, as well as the general prospects for engineering of stable mRNAs are discussed.

Poult Sci, 1992 Jan, 71(1), 76 - 80
Magnesium sulfate effects on coliform bacteria reduction in the intestines, ceca, and carcasses of broiler chickens; Stanley VG et al.; The objective of the study was to evaluate the effects of MgSO4 on intestinal and cecal content reduction with subsequent effects on carcass weight loss and coliform bacterial counts in the intestine and ceca, and on the processed carcass . Four hundred and eighty broiler chicks, 49 days of age, were fed MgSO4 at levels of 0, 2.5, 4.0, 5.5, 7.0, and 8.5 g/L via drinking water 24 h before processing . Samples from the intestinal and cecal contents and swabs from the processed carcass surface were plated for coliform bacteria colonization . The results indicated that carcass weight loss was not affected significantly by MgSO4, irrespective of the levels fed . The mean dressing percentage of the treated chicks was 64.9% compared with 65.2% for the controls . Although the reduction in the intestinal contents was not significant, the coliform bacterial counts declined from 1.4 x 10(6) to 1.4 x 10(4), a reduction of 2 logs when the MgSO4 was administered at 5.5 g/L . However, both the cecal contents and coliform bacteria were reduced significantly when the birds were given 5.5 g/L of MgSO4 . The reduction of the coliform bacteria in the ceca was significant when compared with the control, an approximate reduction of 3 logs . Also, the bacterial counts on the carcass surface were nonsignificantly reduced from 2.2 x 10(4) to 2 x 10(3), a 1-log reduction . Correlation coefficients showed that as the contents of the intestine decreased, the coliform bacterial counts in the ceca and on the carcass surface decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochim Biophys Acta, 1992 Jan 9, 1118(2), 194 - 210
Structure model of core proteins in photosystem I inferred from the comparison with those in photosystem II and bacteria; an application of principal component analysis to detect the similar regions between distantly related families of proteins; Otsuka J et al.; A principal component analysis based on the physico-chemical properties of amino acid residues is developed to assign similar regions between distantly related families of proteins, taking account of the species diversities in respective families . The most important advantage of this analysis should be that it reflects different physico-chemical properties and thus can predict more detailed structural properties, including the transmembrane helices, than the hydropathy analysis . Its first application reconfirms the similarity between the core proteins of photosynthetic reaction center in purple bacteria and those of photosystem II, indicating that the low percentage of identical amino acid residues estimated previously between them is due to much allowance for amino acid substitutions in purple bacteria . The application of this analysis to the core proteins of photosystem I reveals that any of these proteins includes two domains, each showing high similarity to the amino acid sequences of core proteins in photosystem II and purple bacteria . A core structure model of A1 and A2 proteins folded into four layers of sheets of transmembrane helices is proposed to provide a molecular basis for the electron pathway suggested by spectroscopic experiments as well as for the interaction sites with plastocyanin, 9 kDa protein and LHC proteins.

Plasmid, 1992 Jan, 27(1), 41 - 51
Copper resistance determinants in bacteria; Brown NL et al.; Copper is an essential trace element that is utilized in a number of oxygenases and electron transport proteins, but it is also a highly toxic heavy metal, against which all organisms must protect themselves . Known bacterial determinants of copper resistance are plasmid-encoded . The mechanisms which confer resistance must be integrated with the normal metabolism of copper . Different bacteria have adopted diverse strategies for copper resistance, and this review outlines what is known about bacterial copper resistance mechanisms and their genetic regulation.

Scand J Gastroenterol, 1992, 27(1), 77 - 80
Experimental clogging of biliary endoprostheses . Role of bacteria, endoprosthesis material, and design; Dowidar N et al.; The major problem facing patients treated with biliary endoprostheses is their frequent clogging, necessitating their exchange . Clogged endoprostheses contain mainly bacteria embedded in an amorphous proteinaceous material with the occasional presence of food fibres . We studied this problem in an in vitro model, evaluating the role of bacteria, endoprosthesis design, and material in sludge formation . We found endoprostheses perfused with artificially contaminated bile to contain significantly more sludge than those perfused with sterile bile (p less than 0.05) . The amount of sludge varied with the bacterial species used . Endoprostheses perfused with bacteria producing beta-glucuronidase were not associated with a particularly large amount of sludge . Endoprostheses with side holes contained significantly more sludge than those without (p less than 0.05) . Furthermore, endoprostheses made of material with a low friction coefficient, such as Teflon, contained significantly less sludge than endoprostheses made of materials with a higher friction coefficient, such as polyethylene and polyurethane (p less than 0.05) . These results emphasize the role of bacteria in endoprostheses clogging and clearly demonstrate the harmful effect that side holes have on endoprosthesis function.

Electron Microsc Rev, 1992, 5(1), 77 - 103
Freeze-substitution studies of bacteria; Graham LL; Typically, models of bacterial structure combine biochemical data obtained from bulk analyses of cell populations with electron microscopic observation of individual cells . Recent development of a battery of cryotechniques specific for biological electron microscopy have begun to supercede routine procedures such as conventional thin sectioning . One of these cryotechniques, freeze-substitution, combines the advantages of ultrarapid freezing with standard microtomy methods . This technique is particularly well suited to the examination of bacterial structure and has yielded additional ultrastructural information consistent with biochemical data but often challenging models of cell structure obtained from conventional microscopical methods . In addition to retaining more accurately the spatial distribution of cell components, freeze-substitution has been successfully combined with immunochemical labelling techniques and has enabled identification and localization of specific molecules both within the cell and on the cell surface . In this review, I describe current ideas on bacterial ultrastructure, modified in accordance with new data obtained from recent freeze-substitution studies.

Gene Expr, 1992, 2(2), 139 - 46
Detecting interactions between eukaryotic proteins in bacteria; Ma J; Few convenient genetic assays are available to study protein-protein interactions . This report describes a genetic scheme in E . coli to detect protein-protein interactions based on the concept of cooperative DNA binding of two interacting proteins . The yeast regulatory proteins GAL4 and GAL80, which are known to interact with each other, were used to test the scheme . A fusion protein, LexA-GAL80, was found to exert a cooperative effect on the DNA-binding activity of GAL4 as monitored by a bacterial repression assay.

Mol Gen Mikrobiol Virusol, 1992, (1-2), 23 - 9
{Mutations in Francisella tularensis, decreasing the virulence of these bacteria and leading to a change in the immune response upon infection of experimental animals with them}; Aleshkin GI et al.; The research was aimed at isolation of Francisella tularensis mutants possessing the decreased virulence for experimental animals and mediating the changes in the animal immune response . A number of spontaneous and induced mutants of the American and European subtypes of Francisella tularensis were selected for antibiotics resistance or detergent sensitivity . All the obtained mutants have the decreased virulence and differ in their ability to induce the protective antitularemia immunity or ability to induce the humoral immune response in the laboratory animals . The dimeric immunoprecipitation in gel as well as immunoblotting have shown the mutations decreasing the virulence to cause the loss by bacteria of a number of antigenic structures (in case the virulence is completely lost) or changes in antigenic structure resulting in inability of bacteria to induce the humoral immune response when immunizing the laboratory animals . The latter occurs in partially virulent mutants of the vaccine mutant type . The concomitant changes in virulence, ability to cause protective immunity or humoral immune response of the mutants is discussed.

Scand J Rheumatol, 1992, 21(2), 60 - 7
Monoclonal antibodies preventing the development of polyarthritis in rats induced by experimental infection with erysipelas bacteria; Ziesenis A et al.; Monoclonal IgM-antibodies specific for arthritogenic erysipelas bacteria (Erysipelothrix rhusiopathiae, serovar 2, strain T28) were isolated from rats suffering from erysipelas polyarthritis . Four of them (C52, D9, E51, R117) were administered to syngeneic Lewis rats . While D9 and an unrelated rat-IgM-antibody showed no effect, C52 protected partially and R117 as well as E51 fully from all symptoms of erysipelas polyarthritis . Prevention of the disease was associated with a lack of antibody-formation against the erysipelas bacteria . There is evidence that prevention is not due to classical passive immunization, but rather to induction of host mechanisms efficiently activated by "inductive" monoclonal antibodies.

Annu Rev Physiol, 1992, 54, 683 - 714
Behavioral responses in bacteria; Armitage JP; As has been stated, bacteria are able to sense a wide range of environmental stimuli through a variety of receptors and to integrate the different signals to produce a balanced response that maintains them or directs them to an optimum environment for growth . In addition, these simple, neuron-less organisms can adapt to the current concentration or strength of stimuli, i.e . they have a memory of the past . Although different species show responses to different chemicals or stimuli, depending on their niche, a consistent pattern is starting to emerge that links environmental sensing and transcriptional control to the chemosensing system, either directly, as in R . sphaeroides and the PTS system, or indirectly, as in the MCP-dependent system . This suggests a common evolutionary pathway from transcriptional activators to dedicated sensory systems . Currently the majority of detailed investigations into bacterial behavior have been carried out on single stimuli under laboratory conditions using well-fed cells . Only limited analysis, using a range of rhizosphere and pathogenic species, has been carried out on the role of behavioral responses in the wild . While laboratory studies are needed to provide the backbone for eventual in vivo investigations, we should remember the responses of whole cells to changes in their environment under laboratory conditions are essentially artificial compared to the natural environment of most species . Once the basic system is understood, it will be possible to investigate the role of these responses in vivo, under competitive, growth-limiting conditions with multiple gradients.

Cytometry, 1992, 13(2), 188 - 92
Comparison of flow cytometry and epifluorescence microscopy for counting bacteria in aquatic ecosystems; Monfort P et al.; Flow cytometry was used to count bacterial cells from diverse origins: one strain of E . coli, one sample of lake water, and 18 samples of estuary water . To verify the accuracy and the precision of this technique, total bacteria counts made by flow cytometry were compared with counts by direct observation using epifluorescence microscopy . The results of this study showed that flow cytometry was a reliable technique for counting a mixture of bacteria in samples from aquatic ecosystems.

Biomaterials, 1992, 13(1), 25 - 7
In vitro effects of titanium powder on oral bacteria; Elagli K et al.; Biomaterial research has been mostly concerned with biocompatibility, i.e . tissue response, of materials for dental or orthopaedic implantation . In this study, the effects of titanium powder on seven bacterial species commonly found in dental plaque or gingival sulcus, were determined by agar incorporation and by liquid medium culture . In neither culture system could any inhibitory or stimulatory activity be detected.

Poult Sci, 1992 Jan, 71(1), 203 - 7
Research note: isolation of two filamentous bacteria associated with enteritis in turkey poults; Morishita TY et al.; Two microaerophilic filamentous bacteria have been isolated from the intestines of turkey poults exhibiting signs of enteritis . These two filamentous bacteria, denoted as F-1 and F-2, were reinoculated into 4-day-old poults and those poults have shown a reduction in rate of gain when compared with aged-matched controls . Weight reduction was 14% for F-1 and 11% for F-2, respectively, at 21 days of age.

J Periodontal Res, 1992 Jan, 27(1), 34 - 9
Fibrinolytic activity of human gingiva in the presence or absence of plaque bacteria; Cortellini P et al.; Activators of fibrinolysis are found in the gingival connective tissue and in the sulcular epithelium . The influence of plaque bacteria and the related inflammatory reaction on the fibrinolytic activity has been evaluated in the human gingiva . An autohistographic technique was applied to sections taken from three groups of 6 specimens each: group A from clinically healthy sites with plaque index = 1 and no bleeding on probing; group B from areas with unambiguous visual signs of gingivitis, with plaque index = 2-3 and bleeding on probing; group C from sites previously treated with professional toothcleaning twice a week for 3 months and with chlorhexidine mouthrinses twice a day for the final 3 wk, in order to obtain a virtually complete elimination of the plaque bacteria . In group C the plaque index was 0 and there was no bleeding on probing . Connective tissue fibrinolytic activity was present in all the sections from the three groups . The sulcular fibrinolytic activity was observed in all the sections taken from the specimens of groups A and B . In contrast, no fibrinolytic activity was observed over the sulcular area in any section taken from the specimens of group C . Therefore, this study does not support previous claims that healthy sulcular epithelium is capable of releasing activators of fibrinolysis . It can be concluded that the presence of any amount of plaque bacteria is associated with sulcular fibrinolytic activity . Contrarily, the elimination of plaque bacteria is associated with the absence of any detectable sign of fibrinolytic activity in the gingival sulcus.

Adv Exp Med Biol, 1992, 312, 25 - 40
Genetically engineered bacteria to identify and produce anti-viral agents; Grafstrom RH et al.; We have prepared a strain of Escherichia coli that expresses both the HIV protease and a Tet protein which has been modified to contain the HIV protease recognition sequence . When the protease is expressed, the bacteria will not grow in the presence of tetracycline . However, when the protease is inhibited the bacteria can grow in tetracycline containing media (Block and Grafstrom 1990) . We have selected spontaneously arising Tet resistant mutants and have screened them for those that could be producing an inhibitor of HIV protease . The problems in the construction of this strain and the characterization of the various Tetr mutants are discussed.

Annu Rev Genet, 1992, 26, 29 - 50
Translational accuracy and the fitness of bacteria; Kurland CG; There are two aspects of the relationship between translational accuracy and the fitness of bacteria that I hope have been clarified in this review . One is that the impact of translational errors on the fitness of bacteria depends very much on nutritional conditions . It would seem that bacterial populations have the capacity to respond to different growth opportunities by the selection of suitable variants . It is particularly surprising how few mutations seem to be required to transform a slowly growing natural isolate with inefficient as well as inaccurate ribosomes into a growth-optimized laboratory strain . It would not be suprising if the selection of the slow, natural isolate phenotype under starvation conditions is equally facile . Another aspect of the accuracy-fitness relationship worth emphasizing is the strong impact of processivity errors and the weak impact of missense errors on the structures of proteins as well as on the growth of cells . What has been learned about translation mechanisms up to now is really only a preliminary to what remains to be discovered about the movements of tRNA, mRNA, and ribosomal subunits that support the processivity of translation . It would be very useful to have more direct methods at hand with which to study these movements . Likewise, the availability of methods to measure processivity errors in natural isolates would help to round out our view of the variability of the ribosomal mechanisms in nature.

Reprod Nutr Dev, 1992, 32(4), 321 - 9
Degradation of maize stem by two rumen fungal species, Piromyces communis and Caecomyces communis, in pure cultures or in association with cellulolytic bacteria; Roger V et al.; Two species of rumen fungi, Piromyces (Piromonas) communis FL and Caecomyces (Sphaeromonas) communis FG10, were cultured alone or in association with the cellulolytic bacteria Ruminococcus flavefaciens or Fibrobacter succinogenes on maize stem . A kinetic study of the degradation of the substrate was then made . After 48 h of culture, all non-lignified tissues observed by scanning electron microscopy disappeared with P communis and degradation was as complete as that observed in the rumen . In contrast, C communis degraded little of the plant cell walls . The ability of P communis to more rapidly degrade maize stem was probably due to the presence of filamentous rhizoids . The extent of dry matter loss after 8 days of incubation was practically the same in all the monocultures and in the 4 cocultures . However, the rate of degradation was faster in the bacterial than in the fungal monocultures and the co-cultures . No metabolic interaction was observed.

Vopr Virusol, 1992 Jan-Feb, 37(1), 16 - 9
{The use of the vif gene expression product of HIV-1 in bacteria for detecting specific antibodies in the sera of infected persons}; Zverev SIa et al.; A fragment of the genome of human immunodeficiency virus type 1 (HIV-1) coding for p23 protein, the product of vif gene, was cloned in a plasmid vector pUR291 . The resulting recombinant plasmid pLacVif1 was conducive in E . coli cells to the synthesis of a hybrid polypeptide with molecular weight of 136 kDa containing antigenic determinants of p23 protein of HIV-1 . The employment of this polypeptide for analysis of HIV-1-positive sera by indirect enzyme immunoassay showed that vif-specific antibodies were found in 53% of the cases and their appearance was not related to the stage of the disease.

Kansenshogaku Zasshi, 1992 Jan, 66(1), 1 - 5
{Activation of aerobic bacteria used as BOD measurement of seawater}; Matsumoto K et al.; Waste of seawater used for cooling water for machines in some kinds of industries in a littoral district in Sakai City, comes under the application of BOD control of the pollution control ordinance in Osaka Prefecture . But unfortunately the BOD measurement method of seawater sample has not been established . In order to establish the measurement method, we studied the strength of activation of aerobic bacteria in the incubation water used and the dilution water . From our results it was proved that we can use the incubation seawater consisting of more than 10(3) cells/ml general bacteria count and more than 0.50 microgram/l ATP (Adenosin triphosphate) as the incubation water and the artificial seawater as the dilution water.

Microsc Res Tech, 1992 Jan 1, 20(1), 87 - 94
Comparison of alcian blue and ruthenium red effects on preservation of outer envelope ultrastructure in methanotrophic bacteria; Fassel TA et al.; Alcian blue (AB) and ruthenium red (RR) effects on ultrastructural preservation of the bacterial cell envelope of methanotrophs are compared . A previous successful method with RR that enhanced preservation of outer envelope layers in two representative methanotroph species is applied to other genera and species of methanotropic bacteria . Alcian blue is substituted for RR in this en bloc protocol . The effect of AB on preservation of these layers is assessed at the ultrastructural level and compared to RR for all species examined . Further, comparison with freeze etch and a fixation in the absence of either RR or AB is made . Both RR and AB are found to aid preservation and help visualize additional components of the cell envelope which are lost or minimized in a standard fixation not employing these cationic reagents . For some species, images obtained are similar between RR and AB procedures and agree with images seen by freeze etch . For other species, AB preserves extended filamentous material that is partially condensed even with the use of RR . Thus, use of AB improves the preservation of outer envelope structure in these organisms equally or more effectively than use of RR.

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