Vet Microbiol, 2001 Mar 20, 79(2), 171 - 82 Effects of an experimental infection with Actinobacillus pleuropneumoniae on the interferon-alpha and interleukin-6 producing capacity of porcine peripheral blood mononuclear cells stimulated with bacteria, virus or plasmid DNA; Johansson E et al.; The effect of a bacterial infection on interferon-alpha (IFN-alpha) and interleukin-6 (IL-6) production by porcine cells was studied in specific pathogen-free (SPF) pigs, infected intranasally with Actinobacillus pleuropneumoniae serotype 2 . Three experimental groups of five pigs were used: infected non-treated pigs, infected pigs that were treated with enrofloxacin at disease onset, and non-infected, non-treated control pigs . Blood samples were collected from all pigs on the day of infection and on days 1, 4, 7, 13 and 17 post-infection . Sera were analysed for presence of antibodies to A . pleuropneumoniae and for the cytokines IL-6 and IFN-alpha . Ability to produce these cytokines was tested in vitro using whole blood cultures stimulated with inactivated virus (Aujeszky's disease virus infected porcine kidney cells (ADV/PK-15)), inactivated bacteria (A . pleuropneumoniae) or bacterial plasmid (pcDNA3) . All cytokine inducers were used neat or pre-incubated with the transfectious agent lipofectin . IL-6 appeared in the serum of all infected non-treated animals but no IFN-alpha was found in the serum of any of the experimental pigs . Accordingly, the bacteria induced a substantial IL-6 but hardly any IFN-alpha production when tested in vitro . However, following incubation with lipofectin, the inactivated bacteria as well as pcDNA3 became efficient inducers of IFN-alpha in whole blood cultures . The increased IFN-alpha production, previously recorded in vitro during the acute phase of infection with A . pleuropneumoniae, was confirmed using lipofected plasmid DNA and it was indicated that leukocytes obtained from infected but apparently cured animals also exhibited an increased production of IFN-alpha . Thus, even mild/sub-clinical bacterial infections may affect cytokine production in pigs. Appl Environ Microbiol, 2001 Mar, 67(3), 1392 - 5 Recovery and analysis of formyltetrahydrofolate synthetase gene sequences from natural populations of acetogenic bacteria; Leaphart AB et al.; Primers for PCR amplification of partial (1,102 of 1,680 bp) formyltetrahydrofolate synthetase (FTHFS) gene sequences were developed and tested . Partial FTHFS sequences were successfully amplified from DNA from pure cultures of known acetogens, from other FTHFS-producing organisms, from the roots of the smooth cordgrass, Spartina alterniflora, and from fresh horse manure . The amplimers recovered were cloned, their nucleotide sequences were determined, and their translated amino acid sequences were used to construct phylogenetic trees . We found that FTHFS sequences from homoacetogens formed a monophyletic cluster that did not contain sequences from nonhomoacetogens and that FTHFS sequences appear to be informative regarding major physiological features of FTHFS-producing organisms. Appl Environ Microbiol, 2001 Mar, 67(3), 1371 - 4 Oligophilic bacteria as tools to monitor aseptic pharmaceutical production units; Nagarkar PP et al.; The bacterial loads of air, surfaces, and personnel in clean rooms are routinely monitored using a set of standard media . Bacteria that can grow on these media are a tiny fraction of the total numbers in any environment . A substantial proportion of bacteria long thought to be unculturable were recently shown to be oligophilic . Oligophile counts in clean rooms in our studies exceeded the standard plate counts by up to 2 orders of magnitude . They responded to disinfection routines in ways similar to the responses of conventional bacteria . We suggest that oligophiles are better tools than conventional bacteria for environmental monitoring in aseptic pharmaceutical production units. Appl Environ Microbiol, 2001 Mar, 67(3), 1328 - 34 Suboxic deposition of ferric iron by bacteria in opposing gradients of Fe(II) and oxygen at circumneutral pH; Sobolev D et al.; The influence of lithotrophic Fe(II)-oxidizing bacteria on patterns of ferric oxide deposition in opposing gradients of Fe(II) and O(2) was examined at submillimeter resolution by use of an O(2) microelectrode and diffusion microprobes for iron . In cultures inoculated with lithotrophic Fe(II)-oxidizing bacteria, the majority of Fe(III) deposition occurred below the depth of O(2) penetration . In contrast, Fe(III) deposition in abiotic control cultures occurred entirely within the aerobic zone . The diffusion microprobes revealed the formation of soluble or colloidal Fe(III) compounds during biological Fe(II) oxidation . The presence of mobile Fe(III) in diffusion probes from live cultures was verified by washing the probes in anoxic water, which removed ca . 70% of the Fe(III) content of probes from live cultures but did not alter the Fe(III) content of probes from abiotic controls . Measurements of the amount of Fe(III) oxide deposited in the medium versus the probes indicated that ca . 90% of the Fe(III) deposited in live cultures was formed biologically . Our findings show that bacterial Fe(II) oxidation is likely to generate reactive Fe(III) compounds that can be immediately available for use as electron acceptors for anaerobic respiration and that biological Fe(II) oxidation may thereby promote rapid microscale Fe redox cycling at aerobic-anaerobic interfaces. Mol Biochem Parasitol, 2001 Feb, 112(2), 239 - 52 A bifunctional dihydrofolate synthetase--folylpolyglutamate synthetase in Plasmodium falciparum identified by functional complementation in yeast and bacteria; Salcedo E et al.; Folate metabolism in the human malaria parasite Plasmodium falciparum is an essential activity for cell growth and replication, and the target of an important class of therapeutic agents in widespread use . However, resistance to antifolate drugs is a major health problem in the developing world . To date, only two activities in this complex pathway have been targeted by antimalarials . To more fully understand the mechanisms of antifolate resistance and to identify promising targets for new chemotherapies, we have cloned genes encoding as yet uncharacterised enzymes in this pathway . By means of complementation experiments using 1-carbon metabolism mutants of both Escherichia coli and Saccharomyces cerevisiae, we demonstrate here that one of these parasite genes encodes both dihydrofolate synthetase (DHFS) and folylpolyglutamate synthetase (FPGS) activities, which catalyse the synthesis and polyglutamation of folate derivatives, respectively . The malaria parasite is the first known example of a eukaryote encoding both DHFS and FPGS activities in a single gene . DNA sequencing of this gene in antifolate-resistant strains of P . falciparum, as well as drug-inhibition assays performed on yeast and bacteria expressing PfDHFS--FPGS, indicate that current antifolate regimes do not target this enzyme . As PfDHFS--FPGS harbours two activities critical to folate metabolism, one of which has no human counterpart, this gene product offers a novel chemotherapeutic target with the potential to deliver a powerful blockage to parasite growth. Immunol Lett, 2001 Feb 1, 76(1), 63 - 7 A clinically approved oral vaccine against pneumotropic bacteria induces the terminal maturation of CD83+ immunostimulatory dendritic cells; Zelle-Rieser C et al.; Dendritic cells (DCs) are important antigen-presenting cells of the immune system that have attracted interest as cellular adjuvants to induce immunity in clinical settings . We have investigated the effects of Broncho-Vaxom, an oral vaccine composed of lysates from eight pneumotropic bacteria, on human monocyte-derived dendritic cells (moDCs) . Broncho-Vaxom induced the terminal maturation of CD83+ moDCs . MoDCs stimulated with Broncho-Vaxom displayed a phenotype of activated DCs with high levels of major histocompatibility complex (MHC) molecules and increased levels of adhesion and co-stimulatory molecules . In addition, moDCs activated with Broncho-Vaxom exhibited enhanced T cell-stimulatory capacity in the allogeneic mixed leukocyte reaction . Broncho-Vaxom at 100 microg/ml was as potent as TNF-alpha at 1000 U/ml in activating human moDCs . Neither LPS-like activity nor bacterial DNA was found to be responsible for the maturation-inducing activity of Broncho-Vaxom, suggesting that Broncho-Vaxom contains other bacterial factors that are capable of inducing the terminal maturation of moDCs . In DC-based immunotherapy, Broncho-Vaxom could be used as a stimulus of DC maturation, which meets the standards of good manufacturing practice (GMP) . In addition, vaccination with Broncho-Vaxom-loaded moDCs may be an attractive treatment option in preventing recurrent airway infection in predisposed individuals. Indian J Exp Biol, 2000 Feb, 38(2), 160 - 6 Validity of mechanism of gene transfer in the process called conjugation in bacteria; Banerjee M et al.; We have attempted a new evaluation of the process of conjugation in bacteria, because of some basic dissimilarities observed between this and that of eukaryotes, or plants and animals . Reference donor and recipient strains, widely used to prove conjugation in bacteria, were chosen; addition of DNase during the conjugation process, led to an unexpected but highly reproducible increase in the transconjugant colony counts (TCC; ca . > or = 1 log), when compared with that of the controls without DNase . Transconjugants were also obtained when the same live donors were substituted with the UV-killed ones although the TCC was very low initially . Contrarily, donors treated with DNA-intercalating agents, e.g . acridine orange or ethidium bromide, resulted in a complete failure to produce transconjugants . There was a quantitative relationship between the DNase used on donors and levels of DNA sugars/nucleotides/DNA, which possibly resulted from interaction between the DNase and DNA being present/produced on the donor surface . This may be indicative of what may actually happen in the donor-recipient mixtures in the conjugation test proper, where the recipient DNase may activate a donor DNA production cycle . The evidences presented did not suggest that the donor DNA in the conjugation process is actually vestibuled through any intercellular conjugation passages, and is susceptible to the action of DNase or the intercalating dyes. Ultramicroscopy, 2001 Jan, 86(1-2), 121 - 8 Comparative studies of bacteria with an atomic force microscopy operating in different modes; Bolshakova AV et al.; Escherichia coli bacterial cells of two strains JM109 and K12 J62 were imaged with atomic force microscopy (AFM) in different environmental conditions . The AFM results show that the two strains have considerable difference in the surface morphology . At the same time after rehydration both strains show the loss of the topographic features and increase in lateral and vertical dimensions . Results obtained in different AFM modes (contact, tapping, MAC) were compared . Imaging in culture medium was applied for direct observation of the surface degradation effect of lysozyme . The treatment of the cells with the enzyme in the culture medium lead to the loss of surface rigidity and eventually to dramatic changes of the bacteria shape. Int J Syst Evol Microbiol, 2001 Jan, 51(Pt 1), 119 - 22 Hyphomicrobium chloromethanicum sp . nov . and Methylobacterium chloromethanicum sp . nov., chloromethane-utilizing bacteria isolated from a polluted environment; McDonald IR et al.; Two chloromethane-utilizing facultatively methylotrophic bacteria, strains CM2T and CM4T, were isolated from soil at a petrochemical factory . On the basis of their morphological, physiological and genotypical properties, strain CM2T (= VKM B-2176T = NCIMB 13687T) is proposed as a new species of the genus Hyphomicrobium, Hyphomicrobium chloromethanicum, and strain CM4T (= VKM B-2223T = NCIMB 13688T) as a new species of the genus Methylobacterium, Methylobacterium chloromethanicum. Philos Trans R Soc Lond B Biol Sci, 2001 Jan 29, 356(1405), 29 - 39 Hypermutation in bacteria and other cellular systems; Bridges BA; A temporary state of hypermutation can in principle arise through an increase in the rate of polymerase errors (which may or may not be triggered by template damage) and/or through abrogation of fidelity mechanisms such as proofreading and mismatch correction . In bacteria there are numerous examples of transient mutator states, often occurring as a consequence of stress . They may be targeted to certain regions of the DNA, for example by transcription or by recombination . The initial errors are made by various DNA polymerases which vary in their error-proneness: several are inducible and are under the control of the SOS system . There are several structurally related polymerases in mammals that have recently come to light and that have unusual properties, such as the ability to carry out 'accurate' translesion synthesis opposite sites of template damage or the possession of exceedingly high misincorporation rates . In bacteria the initial errors may be genuinely spontaneous polymerase errors or they may be triggered by damage to the template strand, for example as a result of attack by active oxidative species such as singlet oxygen . In mammalian cells, hypermutable states persisting for many generations have been shown to be induced by various agents, not all of them DNA damaging agents . A hypermutable state induced by ionizing radiation in male germ cells in the mouse results in a high rate of sequence errors in certain unstable minisatellite loci; the mechanism is unclear but believed to be associated with recombination events. Z Naturforsch {C}, 2000 Nov-Dec, 55(11-12), 965 - 70 10-Hydroxystearic acid--identified after homogenization of tissue--is derived from bacteria; Adam P et al.; 10-Hydroxystearic acid seems to be widely distributed in nature: Bacteria generate it by hydroxylation of oleic acid, but it was found also as constituent of plants, in cancer cell cultures and in mammalian tissue homogenates . Investigation of 10-hydroxystearic acid, obtained from mammalian tissue homogenates, revealed its identity with that of bacteria . Thus not 10-hydroxystearic acid is widely distributed in nature but its producers: bacteria . When biological material is processed in aqueous media, lipases are activated, these cleave membrane phospholipids . Thus liberated oleic acid is the substrate for widespread bacteria which are introduced into the media when the work up procedure is done in not sterile surrounding . The bacteria transform then oleic acid to 10R-hydroxystearic acid. Orig Life Evol Biosph, 2000 Dec, 30(6), 567 - 77 Fine structure of fossilized bacteria in Volyn kerite; Gorlenko VM et al.; Ultrathin sectioning and cryofracture of fibrous kerite, sampled from 1.8-1.75 billion year old Volyn sediments (Ukraine), revealed in bacteria-like bodies the presence of structures similar to sheath, cell wall, periplasm, cytoplasm, septum, membranes, intramembrane particles, poly-beta-hydroxybutyrate inclusions . On the strength of these data and also the fatty acid profiles of these microfossils, we concluded that fibrous kerites are biogenic formations, namely fossilized bacterial mats. Mikrobiologiia, 2000 Nov-Dec, 69(6), 753 - 63 {Organization and regulation of polyhydroxybutyrate/valerate biosynthesis in bacteria}; Trotsenko IuA et al.; Recent data on the biosynthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/V) and its regulation in bacteria are reviewed, with special emphasis on the properties and regulation of the relevant enzymes and their genes . Some conditions promoting the synthesis of PHB and PHB/V by natural, mutant, and recombinant producers are considered. Subcell Biochem, 2000, 35, 621 - 76 Reaction centres of purple bacteria; van Brederode ME et al.; The bacterial reaction centre is undoubtedly one of the most heavily studied electron transfer proteins and, as this article has tried to describe, it has made some unique contributions to our understanding of biological electron transfer and coupled protonation reactions, and has provided fascinating information in areas that concern basic properties such as protein heterogeneity and protein dynamics . Despite intensive study, much remains to be learned about how this protein catalyses the conversion of solar energy into a form that can be used by the cell . In particular, the dynamic roles played by the protein are still poorly understood . The wide range of time-scales over which the reaction centre catalyses electron transfer, and the relative ease with which electron transfer can be triggered and monitored, will ensure that the reaction centre will continue to be used as a laboratory for testing ideas about the nature of biological electron transfer for many years to come. Stud Health Technol Inform, 2000, 77, 106 - 10 Application of artificial neural network for the identification of fresh water bacteria; Giacomini M et al.; A method based on artificial neural network (ANN) for monitoring aquatic bacteria which would be useful for health care is presented . Environmental micro-organisms include a large number of taxa . Some species that normally are not pathogenic can represent a risk in certain conditions, such as old people and immuno-compromised individuals . A system based on unsupervised ANN has been set up using the fatty acid profiles of standard strains, obtained by gas-chromatography, as learning data . The Kohonen output map resulted in a powerful tool for identification of fresh isolates coming from a line of the major civil water system of Genova (Italy). J Nutr Sci Vitaminol (Tokyo), 2000 Aug, 46(4), 193 - 8 Volatile sulfur production by pig cecal bacteria in batch culture and screening inhibitors of sulfate reducing bacteria; Arakawa T et al.; We studied the effects of specific inhibitors of methanogenesis (2-bromoethane sulfonate, BES) and sulfate reduction (sodium molybdate) on volatile sulfur production in batch cultures of pig cecal bacteria . The volatile sulfur concentration in headspace gas was determined by flame-photometric detector gas chromatography . BES stimulated production of hydrogen sulfide (H2S) and methanethiol, and sodium molybdate completely inhibited the production of these volatile sulfur compounds . The results indicated that dissimilate sulfate reduction is mainly responsible for volatile sulfur production in the hindgut . Therefore the extracts of herbs, food colors, and aroma chemicals were tested for their inhibitory effects on H2S production by a dissimilatory sulfate-reducing bacteria . Desulfovibrio desulfuricans DSM642 . H2S was measured by the chromatography of the headspace gas, using a flame photometric detector . Of 306 herbal extracts tested, 69 extracts from 38 herbs inhibited H2S production at 1.0 mg/mL . Sisymbrium officinale (hedge mustard) was the most potent inhibitor . Six pigments inhibited H2S release . Erythrosine and rose bengal showed inhibitory effects at 0.01 mg/mL . Peppermint oil and 96 aroma chemicals were assayed for their effects on H2S release . Thirty-two aroma chemicals suppressed H2S production at 0.1 mg/mL, and camphene, 1-decanol, and 2-nonanone were effective at 0.01 mg/mL. J Bacteriol, 2001 Feb, 183(3), 1012 - 21 Size comparisons among integral membrane transport protein homologues in bacteria, Archaea, and Eucarya; Chung YJ et al.; Integral membrane proteins from over 20 ubiquitous families of channels, secondary carriers, and primary active transporters were analyzed for average size differences between homologues from the three domains of life: Bacteria, Archaea, and Eucarya . The results showed that while eucaryotic homologues are consistently larger than their bacterial counterparts, archaeal homologues are significantly smaller . These size differences proved to be due primarily to variations in the sizes of hydrophilic domains localized to the N termini, the C termini, or specific loops between transmembrane alpha-helical spanners, depending on the family . Within the Eucarya domain, plant homologues proved to be substantially smaller than their animal and fungal counterparts . By contrast, extracytoplasmic receptors of ABC-type uptake systems in Archaea proved to be larger on average than those of their bacterial homologues, while cytoplasmic enzymes from different organisms exhibited little or no significant size differences . These observations presumably reflect evolutionary pressure and molecular mechanisms that must have been operative since these groups of organisms diverged from each other. Med Sci Monit, 2000 Mar-Apr, 6(2), 291 - 9 Adherence of bile-isolated bacteria to the bile ducts mucosa as a pathogenic factor in the development of inflammatory lesions; Kosowski K et al.; Bacterial infection of the bile system appears to be an important factor in the formation of stones . In view of the hypothesis that strains of E . c . form an essential factor in infections of the bile ducts, an attempt has been made to determine the connection between infections of the bile ducts and the adherence of E . c . to the epithelium of the gallbladder . The research covered 148 patients operated electively for cholecystolithiasis (121), cholecystocholedocholithiasis (26) and recurrent lithiasis (1) . In bile collected from the gallbladder in the course of the operation, E . coli strains were isolated . Cholangioscopy performed in 26 patients enabled the macroscopic evaluation and grading of inflammatory lesions of bile duct mucosa . The mucosa of the gallbladder was evaluated histologically . The adherence test was performed using homologous and heterologous strains of E . c . isolated from the bile of gallstone patients . The adherence occurred most frequently in the neck of the gallbladder (71-100%) in those patients in whom an infectious process of the bile ducts mucosa was endoscopically diagnosed . The adherence of bacteria to the epithelium of the gallbladder did not depend on the type of inflammation (acute, chronic). ALTEX, 1989, 6(2), 27 - 44 {Testing the acute toxicity of chemicals using bacteria}; Hartung J; Two bacterial tests are used to screen the acute toxicity of 8 compounds which are known as pollutants in the air of stables . The procedures applied were batch-microcalorimetry (E.coli) and the Microtox(R)-test (P . phosphoreum) . It is shown that both bacterial "screening models" are suitable to evaluate the acute toxicity of the compounds tested . The test results are compared to results from other toxicity tests using higher developed organisms; additionally the comparison included compounds from the literature . It is found that the results from the different test systems are significantly correlated as far as linear correlation and as rank correlation are concerned . The range of the results supports the suggestion to apply two or more short-term tests involving different test organisms in a "test battery" . Bacterial short-term assays may not completely replace experiments involving animals but they allow an estimation of the toxic potential of substances which have not yet been tested and may thus reduce the necessary amount of experiments with animals. Environ Microbiol, 1999 Oct, 1(5), 457 - 67 Effect of temperature on sulphate reduction, growth rate and growth yield in five psychrophilic sulphate-reducing bacteria from Arctic sediments; Knoblauch C et al.; Five psychrophilic sulphate-reducing bacteria (strains ASv26, LSv21, PSv29, LSv54 and LSv514) isolated from Arctic sediments were examined for their adaptation to permanently low temperatures . All strains grew at -1.8 degrees C, the freezing point of sea water, but their optimum temperature for growth (T(opt)) were 7 degrees C (PSv29), 10 degrees C (ASv26, LSv54) and 18 degrees C (LSv21, LSv514) . Although T(opt) was considerably above the in situ temperatures of their habitats (-1.7 degrees C and 2.6 degrees C), relative growth rates were still high at 0 degrees C, accounting for 25-41% of those at T(opt) . Short-term incubations of exponentially growing cultures showed that the highest sulphate reduction rates occurred 2-9 degrees C above T(opt) . In contrast to growth and sulphate reduction rates, growth yields of strains ASv26, LSv54 and PSv29 were almost constant between -1.8 degrees C and T(opt) . For strains LSv21 and LSv514, however, growth yields were highest at the lowest temperatures, around 0 degrees C . The results indicate that psychrophilic sulphate-reducing bacteria are specially adapted to permanently low temperatures by high relative growth rates and high growth yields at in situ conditions. Environ Microbiol, 1999 Apr, 1(2), 175 - 82 A novel system for efficient gene expression and monitoring of bacteria in aquatic environments; Espinosa-Urgel M et al.; In a previous study, we reported the identification of Escherichia coli genes with increased expression in an aquatic environment . Here, we describe the use of one of these genes, gapC, as an expression system in freshwater habitats . We have identified the transcriptional start site of gapC and analysed the synthesis of the GapC protein during incubation in aquatic medium . The promoter of gapC was used to construct fusions to the reporter genes lacZ and gfp . Analysis of these fusions indicates the potential of gapC as a valuable tool for the detection of E . coli in freshwater habitats, as well as for expressing other genes in aquatic environments. Genome Biol . 2000;1(4):REVIEWS1024 . Epub 2000 Oct 10. Expression profiling in reference bacteria: dreams and reality; Danchin A et al.; Profiling of gene expression in bacteria is now being used to uncover unknown genes expressed in particular genetic backgrounds or environmental conditions . Obtaining the best possible information from the expected avalanche of such experiments will require standardization of both experimental approach and statistical analysis . The first such experiments reveal challenges, pitfalls and reasonable solutions. Infect Immun, 2001 Mar, 69(3), 1364 - 72 Interleukin-8 and intercellular adhesion molecule 1 regulation in oral epithelial cells by selected periodontal bacteria: multiple effects of Porphyromonas gingivalis via antagonistic mechanisms; Huang GT et al.; Interaction of bacteria with mucosal surfaces can modulate the production of proinflammatory cytokines and adhesion molecules produced by epithelial cells . Previously, we showed that expression of interleukin-8 (IL-8) and intercellular adhesion molecule 1 (ICAM-1) by gingival epithelial cells increases following interaction with several putative periodontal pathogens . In contrast, expression of IL-8 and ICAM-1 is reduced after Porphyromonas gingivalis ATCC 33277 challenge . In the present study, we investigated the mechanisms that govern the regulation of these two molecules in bacterially infected gingival epithelial cells . Experimental approaches included bacterial stimulation of gingival epithelial cells by either a brief challenge (1.5 to 2 h) or a continuous coculture throughout the incubation period . The kinetics of IL-8 and ICAM-1 expression following brief challenge were such that (i) secretion of IL-8 by gingival epithelial cells reached its peak 2 h following Fusobacterium nucleatum infection whereas it rapidly decreased within 2 h after P . gingivalis infection and remained decreased up to 30 h and (ii) IL-8 and ICAM-1 mRNA levels were up-regulated rapidly 2 to 4 h postinfection and then decreased to basal levels 8 to 20 h after infection with either Actinobacillus actinomycetemcomitans, F . nucleatum, or P . gingivalis . Attenuation of IL-8 secretion was facilitated by adherent P . gingivalis strains . The IL-8 secreted from epithelial cells after F . nucleatum stimulation could be down-regulated by subsequent infection with P . gingivalis or its culture supernatant . Although these results suggested that IL-8 attenuation at the protein level might be associated with P . gingivalis proteases, the Arg- and Lys-gingipain proteases did not appear to be solely responsible for IL-8 attenuation . In addition, while P . gingivalis up-regulated IL-8 mRNA expression, this effect was overridden when the bacteria were continuously cocultured with the epithelial cells . The IL-8 mRNA levels in epithelial cells following sequential challenge with P . gingivalis and F . nucleatum and vice versa were approximately identical and were lower than those following F . nucleatum challenge alone and higher than control levels or those following P . gingivalis challenge alone . Thus, together with the protease effect, P . gingivalis possesses a powerful strategy to ensure the down-regulation of IL-8 and ICAM-1. Nat Cell Biol, 2001 Feb, 3(2), 210 - 4 Origin of eukaryotic cell nuclei by symbiosis of Archaea in Bacteria is revealed by homology-hit analysis; Horiike T et al.; The origin of eukaryotic cell nuclei by symbiosis of Archaea in Bacteria was proposed on the basis of the phylogenetic topologies of genes . However, it was not possible to conclude whether or not the genes involved were authentic representative genes . Furthermore, using the BLAST and FASTA programs, the similarity of open reading frame (ORF) groups between three domains (Eukarya, Archaea and Bacteria) was estimated at one threshold . Therefore, their similarities at other thresholds could not be clarified . Here we use our newly developed 'homology-hit analysis' method, which uses multiple thresholds, to determine the origin of the nucleus . We removed mitochondria-related ORFs from yeast ORFs, and determined the number of yeast orthologous ORFs in each functional category to the ORFs in six Archaea and nine Bacteria at several thresholds (E-values) using the BLAST . Our results indicate that yeast ORFs related to the nucleus may share their origins with archaeal ORFs, whereas ORFs that are related to the cytoplasm may share their origins with bacterial ORFs . Our results thus strongly support the idea of nucleus symbiosis. Biochemistry (Mosc), 2000 Dec, 65(12), 1429 - 34 Why is electron transport in the reaction centers of purple bacteria unidirectional? Borisov AY. Although the two electron-transfer branches in the reaction centers (RC) of purple bacteria are virtually symmetric, it is well known that only one of them is functionally active (the A-branch) . The mechanisms of functional asymmetry of structurally symmetric branches of the electron transport system are analyzed in this work within the framework of the theory of bimolecular charge-transfer complexes (CTC) . CTC theory is shown to provide an explanation of this phenomenon . According to the CTC theory, the dominance of one branch is required to implement the CTC state in special bacteriochlorophyll pairs of RC, in which more than 30% of the excited electron density in the CTC is shifted toward one of the bacteriochlorophyll molecules . This causes a significant increase in the efficiency of further electron transfer to the primary quinone acceptor as compared to a system with two absolutely symmetric electron transfer branches . Specific features of dielectric asymmetry near the RC special pair are discussed . It is emphasized that a strong CTC is able to provide effective trapping of electronic excitation energy from antenna chlorophyll, which is a main function of the RC . Hypothetical stages of CTC formation in other classes of photosynthesizing bacteria during evolution are discussed. J Microbiol Methods, 2001 Mar 1, 44(2), 183 - 91 The use of a solid adsorber resin for enrichment of bacteria with toxic substrates and to identify metabolites: degradation of naphthalene, O-, and m-xylene by sulfate-reducing bacteria; Morasch B et al.; Anaerobic sulfate-reducing bacteria were enriched from contaminated aquifer samples with naphthalene, o-, and m-xylene as sole carbon and energy source in the presence of Amberlite-XAD7, a solid adsorber resin . XAD7 served as a substrate reservoir maintaining a constantly low substrate concentration in the culture medium . In equilibration experiments with XAD7, the aromatic hydrocarbons needed up to 5 days to achieve equilibrium between the water and the XAD7 phase . The equilibrium concentration was directly correlated with the amount of added substrate and XAD7 . In the enrichments presented here, XAD7 and aromatic hydrocarbons were adjusted to maintain substrate concentrations of 100 microM m-, or o-xylene, or 50 microM naphthalene . After five subsequent transfers, the three cultures were able to grow with higher substrate concentrations in the absence of XAD7 although they grew best with lower hydrocarbon concentrations . Two new xylene-degrading cultures were obtained that could not utilise toluene as carbon source . O-xylene was degraded anaerobically by a culture, which could also oxidise m-xylene but not p-xylene . Eighty-three percent of the electrons from o-xylene oxidation were recovered in the produced sulfide, indicating a complete oxidation to CO2 . Another sulfate-reducing enrichment culture oxidised m-xylene completely to CO2 but not o-, or p-xylene . A naphthalene-degrading sulfate-reducing enrichment culture oxidised naphthalene completely to CO2 . Metabolites of naphthalene degradation were recovered from the XAD7 phase and subjected to GC/MS analysis . Besides the metabolites 2-naphthoic acid and decahydro-2-naphthoic acid which were identified by the mass spectrum and coelution with chemically synthesised reference compounds, the reduced 2-naphthoic acid derivatives 5,6,7,8-tetrahydro-2-naphthoic acid and octahydro-2-naphthoic acid were tentatively identified by their mass spectra . Cultivation of bacterial cultures in the presence of XAD7 and subsequent derivatisation and extraction of metabolites directly from the solid XAD7 resin provides a new method for the isolation of sensitive bacteria and identification of metabolites. J Microbiol Methods, 2001 Mar 1, 44(2), 121 - 9 How to optimize the drop plate method for enumerating bacteria; Herigstad B et al.; The drop plate (DP) method can be used to determine the number of viable suspended bacteria in a known beaker volume . The drop plate method has some advantages over the spread plate (SP) method . Less time and effort are required to dispense the drops onto an agar plate than to spread an equivalent total sample volume into the agar . By distributing the sample in drops, colony counting can be done faster and perhaps more accurately . Even though it has been present in the laboratory for many years, the drop plate method has not been standardized . Some technicians use 10-fold dilutions, others use twofold . Some technicians plate a total volume of 0.1 ml, others plate 0.2 ml . The optimal combination of such factors would be useful to know when performing the drop plate method.This investigation was conducted to determine (i) the standard deviation of the bacterial density estimate, (ii) the cost of performing the drop plate procedure, (iii) the optimal drop plate design, and (iv) the advantages of the drop plate method in comparison to the standard spread plate method . The optimal design is the combination of factor settings that achieves the smallest standard deviation for a fixed cost . Computer simulation techniques and regression analysis were used to express the standard deviation as a function of the beaker volume, dilution factor, and volume plated . The standard deviation expression is also applicable to the spread plate method. J Biotechnol, 2001 Jan 23, 85(1), 25 - 33 Acetate as a carbon source for hydrogen production by photosynthetic bacteria; Barbosa MJ et al.; Hydrogen is a clean energy alternative to fossil fuels . Photosynthetic bacteria produce hydrogen from organic compounds by an anaerobic light-dependent electron transfer process . In the present study hydrogen production by three photosynthetic bacterial strains (Rhodopseudomonas sp., Rhodopseudomonas palustris and a non-identified strain), from four different short-chain organic acids (lactate, malate, acetate and butyrate) was investigated . The effect of light intensity on hydrogen production was also studied by supplying two different light intensities, using acetate as the electron donor . Hydrogen production rates and light efficiencies were compared . Rhodopseudomonas sp . produced the highest volume of H2 . This strain reached a maximum H2 production rate of 25 ml H2 l(-1) h(-1), under a light intensity of 680 micromol photons m(-2) s(-1), and a maximum light efficiency of 6.2% under a light intensity of 43 micromol photons m(-2) s(-1) . Furthermore, a decrease in acetate concentration from 22 to 11 mM resulted in a decrease in the hydrogen evolved from 214 to 27 ml H2 per vessel. Small Rumin, Res. . 2001 Jan, 39(1), 73 - 85 Reproductive performance of South African indigenous goats inoculated with DHP-degrading rumen bacteria and maintained on Leucaena leucocephala/grass mixture and natural pasture; Akingbade AA et al.; This study examined the reproductive performance of dihydroxy pyridone (DHP)-inoculated South African indigenous (SAIG) female goats maintained on two dietary treatments: (i) Leucaena leucocephala/grass mixture and (ii) natural pasture prior to conception, and during gestation . Leucaena leucocephala/grass mixture was nutritionally superior (crude protein and mineral elements) than the natural pasture . The average daily gain, products of pregnancy and foetal development in gravid goats raised on leucaena/grass mixture were significantly (P<0.03, P<0.009 and P<0.005, respectively) higher than those raised on natural pasture . Conception rate of goats fed natural pasture was higher than the band fed Leucaena leucocephala/grass mixture . Leucaena/grass mixture fed goats had kids that were heavier at birth than their counterparts on natural pasture . Pre-weaning kid mortality over the period of study was significantly (P<0.01) higher in the Leucaena leucocephala/grass mixture treatment . Colostrum from kidded goats fed leucaena was viscous and difficult to sample . The absence of mimosine toxicity symptoms suggests a possibility of safe use of leucaena as a feed resource to DHP-inoculated SAIG. Appl Environ Microbiol, 2001 Feb, 67(2), 1015 - 9 Nickel-resistance-based minitransposons: new tools for genetic manipulation of environmental bacteria; Taghavi S et al.; The ncc and nre nickel resistance determinants from Ralstonia eutropha-like strain 31A were used to construct mini-Tn5 transposons . Broad host expression of nickel resistance was observed for the nre minitransposons in members of the alpha, beta, and gamma subclasses of the Proteobacteria, while the ncc minitransposons expressed nickel resistance only in R . eutropha-like strains. Appl Environ Microbiol, 2001 Feb, 67(2), 972 - 6 Quantification of ammonia-oxidizing bacteria in arable soil by real-time PCR; Hermansson A et al.; Real-time PCR was used to quantify populations of ammonia-oxidizing bacteria representing the beta subdivision of the class Proteobacteria in samples of arable soil, both nitrogen fertilized and unfertilized, from Mellby, Sweden . Primers and probes targeting a 16S ribosomal DNA region of the ammonia-oxidizing bacteria were designed and used . In the fertilized soil there were approximately 6.2 x 10(7) ammonia-oxidizing bacteria per g of soil, three times more than the number of bacteria in the unfertilized soil . The lytic efficiency of bead beating in these soils was investigated by using populations of free or loosely attached bacteria, bacteria tightly bound to particles, and bacteria in nonfractionated samples . The shapes of the curves generated in these tests showed that the concentration of template DNA released at various times remained constant after 10 to 100 s of bead beating. Appl Environ Microbiol, 2001 Feb, 67(2), 814 - 20 Effects of hydrophobic and electrostatic cell surface properties of bacteria on feeding rates of heterotrophic nanoflagellates; Matz C et al.; The influence of cell surface hydrophobicity and electrostatic charge of bacteria on grazing rates of three common species of interception-feeding nanoflagellates was examined . The hydrophobicity of bacteria isolated from freshwater plankton was assessed by using two different methods (bacterial adhesion to hydrocarbon and hydrophobic interaction chromatography) . The electrostatic charge of the cell surface (measured as zeta potential) was analyzed by microelectrophoresis . Bacterial ingestion rates were determined by enumerating bacteria in food vacuoles by immunofluorescence labelling via strain-specific antibodies . Feeding rates varied about twofold for each flagellate species but showed no significant dependence on prey hydrophobicity or surface charge . Further evidence was provided by an experiment involving flagellate grazing on complex bacterial communities in a two-stage continuous culture system . The hydrophobicity values of bacteria that survived protozoan grazing were variable, but the bacteria did not tend to become more hydrophilic . We concluded that variability in bacterial cell hydrophobicity and variability in surface charge do not severely affect uptake rates of suspended bacteria or food selection by interception-feeding flagellates. Oral Microbiol Immunol, 2000 Dec, 15(6), 371 - 7 Attachment of Fusobacterium nucleatum PK1594 to mammalian cells and its coaggregation with periodontopathogenic bacteria are mediated by the same galactose-binding adhesin; Weiss EI et al.; It has been shown that Fusobacterium nucleatum PK1594 coaggregates with Prophyromonas gingivalis PK1924 through a galactose-binding adhesin . In the present study, attachment of F . nucleatum PK1594 to a variety of mammalian cells was characterized . F . nucleatum PK1594 attached to all eukaryotic cells tested, including human buccal epithelial cells, gingival and periodontal ligament fibroblasts, HeLa cells and murine lymphocytes, macrophages, and polymorphonuclear leukocytes . These attachments were (i) inhibited by galactose, lactose and N-acetylgalactosamine and (ii) inhibited by monoclonal antibody specific for the galactose-binding adhesin of F . nucleatum PK1594 . In addition, a coaggregation-defective mutant of F . nucleatum PK1594 (PK2172), which does not exhibit galactose binding activity, did not attach to the mammalian cells . Coaggregation of F . nucleatum PK1594 with P . gingivalis PK 1924 and Actinobacillus actinomycetemcomitans JP2, but not with other bacteria, showed a similar pattern with sugars, monoclonal antibody, and the adhesin-deficient mutant . The results suggest that the attachment of F . nucleatum PK1594 to mammalian cells and its coaggregation with periodontal pathogens are mediated by the same galactose-binding adhesin. Vitam Horm, 2001, 61, 157 - 71 The biosynthesis of coenzyme A in bacteria; Begley TP et al.; Coenzyme A (I) and enzyme-bound phosphopantetheine (II) function as acyl carriers and as carbonyl activating groups for Claisen reactions as well as for amide-, ester-, and thioester-forming reactions in the cell . In so doing, these cofactors play a key role in the biosynthesis and breakdown of fatty acids and in the biosynthesis of polyketides and nonribosomal peptides . Coenzyme A is biosynthesized in bacteria in nine steps . The biosynthesis begins with the decarboxylation of aspartate to give beta-alanine . Pantoic acid is formed by the hydroxymethylation of alpha-ketoisovalerate followed by reduction . These intermediates are then condensed to give pantothenic acid . Phosphorylation of pantothenic acid followed by condensation with cysteine and decarboxylation gives 4'-phosphopantetheine . Adenylation and phosphorylation of 4'-phosphopantetheine completes the biosynthesis of coenzyme A . This review will focus on the mechanistic enzymology of coenzyme A biosynthesis in bacteria. Vitam Horm, 2001, 61, 103 - 19 The biosynthesis of nicotinamide adenine dinucleotides in bacteria; Begley TP et al.; The nicotinamide adenine dinucleotides (NAD, NADH, NADP, and NADPH) are essential cofactors in all living systems and function as hydride acceptors (NAD, NADP) and hydride donors (NADH, NADPH) in biochemical redox reactions . The six-step bacterial biosynthetic pathway begins with the oxidation of aspartate to iminosuccinic acid, which is then condensed with dihydroxyacetone phosphate to give quinolinic acid . Phosphoribosylation and decarboxylation of quinolinic acid gives nicotinic acid mononucleotide . Adenylation of this mononucleotide followed by amide formation completes the biosynthesis of NAD . An additional phosphorylation gives NADP . This review focuses on the mechanistic enzymology of this pathway in bacteria. Berl Munch Tierarztl Wochenschr, 2000 Nov-Dec, 113(11-12), 423 - 30 {Coxiella burnetii infections and infections with bacteria of the genus Chlamydia in dairy cattle}; Sting R et al.; Comparative studies on the prevalence of infections caused by Coxiella burnetii (C . burnetii) and Chlamydia were carried out with 592 cattle older than 2 years and 234 cattle younger than 2 years . Of these 477 originated from 24 dairy herds with considerable fertility problems (positive herds) and 349 from 14 dairy herds without major fertility problems (control herds) . For the direct detection of these pathogens in the genitals capture ELISAs were employed, for the demonstration of antibodies the complement fixation test (CFT) . Direct detection of C . burnetii and Chlamydia single as well as mixed infection revealed significant higher values for cattle from positive herds compared with those from the control herds . Animals revealing insemination ratios of > or = 2 showed significantly more frequent excretion of Chlamydia via the genitals and antibodies against C . burnetii than cattle with an insemination ratio of < 2 . Investigations of cows which had had an abortion showed no indications of significantly more frequent C . burnetii or chlamydial infections . Inseminated but non-pregnant cows excreted significantly more C . burnetii and Chlamydia than pregnant cows . Clinical signs of endometritis were associated with an enhanced excretion of Chlamydia . Animals younger than 2 years excreted significantly more frequently C . burnetii but not Chlamydia via the genitals than animals older than 2 years . Indirect test showed results vice versa. Eur J Med Res, 2000 Dec 29, 5(12), 523 - 9 Effect of three mouthrinses, containing amine/stannous fluoride, herbal extracts or Emser salt on the growth of oral bacteria--an in vitro study; Kagermeier-Callaway AS et al.; BACKGROUND/AIMS: Clinical studies have shown the efficacy of mouthrinses in reducing plaque accumulation and inflammation of oral tissues . The aim of this in vitro study was to compare the effect of three mouthrinses: Meridol, an organic amine/ stannous fluoride solution; Parodontax, containing herbal ingredients; and an 0.8 % Emser salt solution, on the growth of oral bacteria and dental plaque . METHODS: Growth of Actinomyces viscosus T14V, Capnocytophaga ochracea 25, C . sputigena 4, Actinobacillus actinomycetemcomitans (A.a.) Y4, and pooled supragingival plaque in the presence of the various mouthrinses, applied to paper discs, was tested in an agar diffusion test . In a second series of tests, the 4 bacterial strains were exposed to the agents for about 3 min to simulate rinsing, then the agent was removed, and the bacteria were inoculated into fresh nutrient broth . After 48 h bacterial growth was measured in a spectrophotometer and compared with the controls . RESULTS: In the agar diffusion test only Meridol, the organic amine/stannous fluoride-containing solution, could inhibit bacterial growth, except for A . a . Y4 . When the bacteria where in contact with the agents for only a few minutes these results were confirmed . Neither Paradontax nor Emser salt inhibited the growth of the bacteria, and A . a . Y4 proved to be resistant to all three agents . Growth of the other three strains was inhibited by Meridol 92-99% (undiluted), 85-96% (1:5) and 83-98% (1:10) . CONCLUSIONS: We conclude that only Meridol contains ingredients capable of inhibiting the growth of oral bacteria in vitro . The efficacy of the other two mouthrinses in reducing plaque accumulation in vivo has to be explained by other mechanisms. Trends Biotechnol, 2001 Jan, 19(1), 15 - 20 Bacteria as workers in the living factory: metal-accumulating bacteria and their potential for materials science; Klaus-Joerger T et al.; Metal micro-/nano-particles with suitable chemical modification can be organized into new ceramic-metal (cermet) or organic-metal (orgmet) composites or structured materials . These materials are attracting significant attention because of their unique structures and highly optimized properties . However, the synthesis of composite materials with inhomogeneities on the nanometer or sub-micrometer scale is a continuing challenge in materials science . Many industrial physical and chemical surface-coating processes using conventional techniques are both energy and cost inefficient and require sophisticated instrumentation . In the future, biology might offer a superior option. Dis Aquat Organ, 2000 Nov 14, 43(2), 153 - 7 Use of prawn blood agar hemolysis to screen for bacteria pathogenic to cultured tiger prawns Penaeus monodon; Chang CI et al.; A newly developed prawn blood agar consisting of 1 ml of tiger prawn hemolymph in medium containing 200 ppm Rose Bengal was used to determine the hemolytic activity of 35 isolates of bacteria obtained from cultured tiger prawns Penaeus monodon and their rearing water . For comparison, the hemolytic activity of these isolates was also determined in sheep blood agar . Nine isolates (25.7% of total) showed different hemolytic reactions on prawn blood agar and sheep blood agar . From the 35 isolates, 8 with various hemolytic characteristics were selected and the relationship between the type of hemolytic activity and pathogenicity was determined and compared . Four isolates that showed hemolytic activity in prawn blood agar caused high mortality to cultured tiger prawns . By contrast, a significantly lower mortality rate was observed for tiger prawns injected with 4 isolates that did not exhibit hemolytic activity on prawn blood agar . Results further showed that mortality did not correlate with hemolytic activity determined using sheep blood agar . Prawn blood agar containing P . monodon hemocytes was faster and more accurate for determining prawn hemolytic activity of bacterial isolates. Appl Environ Microbiol, 2001 Jan, 67(1), 307 - 16 Chloromethane utilization gene cluster from Hyphomicrobium chloromethanicum strain CM2(T) and development of functional gene probes to detect halomethane-degrading bacteria; McAnulla C et al.; Hyphomicrobium chloromethanicum CM2(T), an aerobic methylotrophic member of the alpha subclass of the class proteobacteria, can grow with chloromethane as the sole carbon and energy source . H . chloromethanicum possesses an inducible enzyme system for utilization of chloromethane, in which two polypeptides (67-kDa CmuA and 35-kDa CmuB) are expressed . Previously, four genes, cmuA, cmuB, cmuC, and purU, were shown to be essential for growth of Methylobacterium chloromethanicum on chloromethane . The cmuA and cmuB genes were used as probes to identify homologs in H . chloromethanicum . A cmu gene cluster (9.5 kb) in H . chloromethanicum contained 10 open reading frames: folD (partial), pduX, orf153, orf207, orf225, cmuB, cmuC, cmuA, fmdB, and paaE (partial) . CmuA from H . chloromethanicum (67 kDa) showed high identity to CmuA from M . chloromethanicum and contains an N-terminal methyltransferase domain and a C-terminal corrinoid-binding domain . CmuB from H . chloromethanicum is related to a family of methyl transfer proteins and to the CmuB methyltransferase from M . chloromethanicum . CmuC from H . chloromethanicum shows identity to CmuC from M . chloromethanicum and is a putative methyltransferase . folD codes for a methylene-tetrahydrofolate cyclohydrolase, which may be involved in the C(1) transfer pathway for carbon assimilation and CO(2) production, and paaE codes for a putative redox active protein . Molecular analyses and some preliminary biochemical data indicated that the chloromethane utilization pathway in H . chloromethanicum is similar to the corrinoid-dependent methyl transfer system in M . chloromethanicum . PCR primers were developed for successful amplification of cmuA genes from newly isolated chloromethane utilizers and enrichment cultures. Cytogenet Cell Genet, 2000, 90(3-4), 330 - 6 Isolation and characterization of a novel human gene, NIF3L1, and its mouse ortholog, Nif3l1, highly conserved from bacteria to mammals; Tascou S et al.; We report the cloning and characterization of novel human and murine genes NIF3L1 and Nif3l1 which are strongly homologous to the yeast Ngg1-interacting factor 3 homolog . Mouse Nif3l1 and human NIF3L1 encode predicted proteins of 376 amino acids and 377 amino acids, respectively . Northern blot analysis on RNA from different postnatal murine tissues showed a ubiquitous expression pattern of mouse Nif3l1 with a transcript of approximately 1.85 kb . RT-PCR analysis on prenatal mouse RNA and embryonic stem cell RNA demonstrated expression of Nif3l1 throughout embryonic development . Additionally, expression analysis on cell lines revealed strong overexpression of Nif3l1 in the spermatogonia-derived cell line GC-1 spg and in the teratocarcinoma cell line F9 . The mouse gene was mapped to chromosome 1, region C . Human NIF3L1 consists of seven exons spanning 14.5 kb of genomic DNA and is located on chromosome 2q33 . A fusion protein consisting of the GFP (green fluorescent protein) and the ORF of human NIF3L1 showed a localization of the predicted protein in the cytoplasm . In the N-terminal and C-terminal region, mouse Nif3l1 and human NIF3L1 are strongly homologous to proteins of other species, e.g . the recently cloned Drosophila symbol=anon-35F/36F gene with 41% amino acid identity and several proteins from yeast including the yeast Ngg1-interacting factor 3 homolog with 46% amino acid identity, the hypothetical protein YGL221c and yeast Ngg1-interacting factor 3 (Nif3) with 37% amino acid identity . Other proteins from lower organisms, e.g a conserved hypothetical protein from Ureaplasma urealyticum or a hypothetical protein SCC30.09c from Streptomyces coelicolor show approximately 25-30% amino acid identity in the two flanking regions of the protein . These similarities indicate a high degree of conservation of mouse Nif3l1 and human NIF3L1 from bacteria to mammals . J Appl Microbiol, 2000 Dec, 89(6), 1038 - 47 Mixing and sulphate-reducing activity of bacteria in swelling, compacted bentonite clay under high-level radioactive waste repository conditions; Pedersen K et al.; AIM: The fate of micro-organisms in the bentonite clay surrounding high-level radioactive waste (HLW)-containing copper canisters in a future Swedish underground (500 m) repository were investigated . METHODS AND RESULTS: Laboratory experiments were designed in which the mixing of various bacterial species with swelling bentonite was studied . A clear trend of fewer cultivable bacteria at depth was seen in the clay . This trend was consistent as the incubation time was increased from 8 h to 28 weeks . Sulphate-reducing bacteria were found to be active, reducing sulphate at the lowest density studied, 1.5 g cm-3, but sulphate reduction activity ceased at higher densities . CONCLUSIONS: The number of viable micro-organisms in an HLW repository bentonite clay buffer will decrease rapidly during swelling and very few viable cells will be present at full compaction . SIGNIFICANCE AND IMPACT OF THE STUDY: Sulphate-reducing bacteria will most probably not be able to induce corrosion of HLW-containing copper canisters. J Microbiol Methods, 2000 Dec 15, 43(2), 73 - 80 DNA extraction from coral reef sediment bacteria for the polymerase chain reaction; Guthrie JN et al.; A rapid and effective method for the direct extraction of high molecular weight amplifiable DNA from two coral reef sediments was developed . DNA was amplified by the polymerase chain reaction (PCR) using 16S rDNA specific primers . The amplicons were digested with HaeIII, HinP1I and MspI and separated using polyacrylamide gel electrophoresis and silver staining . The resulting amplified ribosomal DNA restriction analysis (ARDRA) patterns were used as a fingerprint to discern differences between the coral reef sediment samples . Results indicated that ARDRA is an effective method for determining differences within the bacterial community amongst different environmental samples. Metab Eng, 2000 Oct, 2(4), 328 - 38 Low-copy plasmids can perform as well as or better than high-copy plasmids for metabolic engineering of bacteria; Jones KL et al.; Multicopy plasmids are often chosen for the expression of recombinant genes in Escherichia coli . The high copy number is generally desired for maximum gene expression; however, the metabolic burden effects that usually result from multiple plasmid copies could prove to be detrimental for maximum productivity in certain metabolic engineering applications . In this study, low-copy mini-F plasmids were compared to high-copy pMB1-based plasmids for production of two metabolites in E . coli: polyphosphate (polyP) and lycopene derived from isopentenyl diphosphate (IPP) . The stationary-phase accumulation of polyP on a per cell basis was enhanced approximately 80% when either high- or low-copy plasmids were used, from 120 micromol/g DCW without augmented polyP kinase (PPK) activity to approximately 220 micromol/g DCW . The cell density of the high-copy plasmid-containing culture at stationary phase was approximately 24% lower than the low-copy culture and 30% lower than the control culture . This difference in cell density is likely a metabolic burden effect and resulted in a lower overall product concentration for the high-copy culture (approximately 130 micromol/L culture) relative to the low-copy culture (approximately 160 micromol/L culture) . When the gene for DXP (1-deoxy-D-xylulose 5-phosphate) synthase, the first enzyme in the IPP mevalonate-independent biosynthetic pathway, was expressed from the tac promoter on multicopy and low-copy plasmids, lycopene production was enhanced two- to threefold over that found in cells expressing the chromosomal copy only . Cell growth and lycopene production decreased substantially when isopropyl beta-D-thiogalactosidase (IPTG) was added to the high-copy plasmid-containing culture, suggesting that overexpression of DXP synthase was a significant metabolic burden . In the low-copy plasmid-containing culture, no differences in cell growth or lycopene production were observed with any IPTG concentrations . When dxs was placed under the control of the arabinose-inducible promoter (P(BAD)) on the low-copy plasmid, the amount of lycopene produced was proportional to the arabinose concentration and no significant changes in cell growth resulted . These results suggest that low-copy plasmids may be useful in metabolic engineering applications, particularly when one or more of the substrates used in the recombinant pathway are required for normal cellular metabolism. J Microbiol Methods, 2001 Jan, 43(3), 213 - 22 Method for enumeration of 5-cyano-2,3-ditoyl tetrazolium chloride (CTC)-active cells and cell-specific CTC activity of benthic bacteria in riverine, estuarine and coastal sediments; Proctor LM et al.; Bacteria are the most abundant and active organisms in marine sediments and are critical for nutrient cycling and as a food source to many benthic and pelagic organisms . Bacteria are found both as free-living cells and as particle-associated cells, which can make investigations of these communities difficult . We found that common procedures for extracting bacteria from sediments leave the bacteria clay particle-associated and the clay particles clump, which reduce the reproducibility of direct counts . We optimized a sonication/surfactant method that produces a homogeneous suspension of bacterial cells against a uniform background of clay particles, which results in reproducible samples for epifluorescence microscopy . We developed a method to estimate CTC-positive cells and cell-specific CTC content in intact cores of surficial sediment communities from riverine, estuarine and coastal sites . Benthic bacterial abundances averaged 4.9x10(8) cells/g dry wt sediments in Apalachicola River, Florida sediments, 4.9-13.8x10(9) cells/g dry wt sediments in a variety of Apalachicola Bay sediments and 3.6x10(8) cells/g dry weight in shallow, anoxic Gulf of Mexico sediments . Percent CTC-positive cells ranged from low values of 9-10% CTC-positive cells in Apalachicola River and Apalachicola Bay sediments to high values of 25% CTC-positive cells in anoxic Gulf of Mexico sediments . After correction for abiotic CTC reduction and chlorophyll interference, estimates of cell-specific CTC reduction ranged from 0.15 to 0.55 fmol CTC(red)/active cell in the Apalachicola Bay sediments to 1.6 to 3.8 fmol CTC(red)/active cell in anoxic Gulf of Mexico sediments. Biochemistry (Mosc), 2000 Nov, 65(11), 1266 - 71 The widely accepted model of primary photosynthetic processes in purple bacteria must be revised; Borisov AY; Using computer simulation, it was found that, at least in case of purple bacteria, the widely accepted model for the primary photosynthetic processes (energy migration to reaction centers and its further trapping) is unable to provide a fully consistent explanation for the available experimental data . Two physical mechanisms suggested in this work are thought to be able to resolve or at least decrease the severity of this problem. Int Microbiol, 2000 Jun, 3(2), 81 - 8 How bacteria protect themselves against channel-forming colicins; Alonso G et al.; Here we review the mechanisms that bacterial cells use to protect themselves against channel-forming colicins . Four mechanisms are examined: immunity, resistance, tolerance and PacB character . Immunity confers protection to colicinogenic cells against the colicin they produce, since the colicinogenic plasmid bears the genetic determinant for such immunity protein . Resistance is provided by modifications on colicin receptors located on the outer membrane . It prevents colicin adsorption and protects against those colicins sharing a common receptor . Tolerance is achieved by changes in the translocation system . The adsorbed colicin is not translocated toward the periplasmic space . This impedes its insertion into the cell membrane as well as the formation of the transmembrane channel . Tolerance confers protection against colicins that share the same translocation system . Finally, we discuss the PacB character, that confers protection against all known channel-forming colicins . The latter property is encoded by non-colicinogenic plasmids in the H-incompatibility complex. Int Microbiol, 2000 Mar, 3(1), 3 - 8 Oxidative stress in bacteria and protein damage by reactive oxygen species; Cabiscol E et al.; The advent of O2 in the atmosphere was among the first major pollution events occurred on earth . The reaction between ferrous iron, very abundant in the reductive early atmosphere, and oxygen results in the formation of harmful superoxide and hydroxyl radicals, which affect all macromolecules (DNA, lipids and proteins) . Living organisms have to build up mechanisms to protect themselves against oxidative stress, with enzymes such as catalase and superoxide dismutase, small proteins like thioredoxin and glutaredoxin, and molecules such as glutathione . Bacterial genetic responses to oxidative stress are controlled by two major transcriptional regulators (OxyR and SoxRS) . This paper reviews major key points in the generation of reactive oxygen species in bacteria, defense mechanisms and genetic responses to oxidative stress . Special attention is paid to the oxidative damage to proteins. Int Microbiol, 1999 Dec, 2(4), 233 - 40 Light absorption by phototrophic bacteria: effects of scattering, cell concentration and size of the culture vessel; Sanchez O et al.; This article analyzes how absorption of light by suspensions of phototrophic bacteria is modulated by changes in the biomass of the culture, the size of the culture vessel and by the presence of refractile structures within the cells . Increases in biomass and culture size result in higher rates of light absorption but in the decrease of the amount of energy available per cell . The presence of refractile structures has different consequences depending on the biomass concentration . In dense cultures, the accumulation of refractile structures increases the reflection of light, and also reduces specific light absorption . In diluted cultures, however, the effect is the opposite, and refractile structures seem to increase light absorption. Ann R Coll Surg Engl, 2000 Nov, 82(6), 405 - 7 The passage of bacteria through surgical drapes; Blom A et al.; The passage of bacteria through surgical drapes is a potential cause of wound infection . Previous studies have shown that liquids and human albumin penetrate certain types of drapes . We studied the passage of bacteria through seven different types of surgical drape and an operating tray . Bacteria easily penetrated all the woven re-usable fabrics within 30 min . The disposable non-woven drapes proved to be impermeable, as did the operating tray . We recommend the use of non-woven disposable drapes or woven drapes with an impermeable operating tray in all surgical cases. FEMS Microbiol Ecol, 2000 Sep 1, 33(3), 171 - 180 Uncultured giant sulfur bacteria of the genus Achromatium; Head IM et al.; Achromatium is a genus of large unicellular sulfur bacteria . Despite being first described in the late 19th century, no Achromatium spp . have yet been isolated in culture, and for over 100 years, knowledge of their ecology, physiology and relationships to other bacteria has been scant . In recent years, the application of culture-independent techniques combined with in situ process measurements and single-cell activity measurements in sediments harbouring large Achromatium populations, has expanded our knowledge of these bacteria . Aspects of carbon and sulfur metabolism in Achromatium are now better understood, but their preferred electron acceptor(s) remain unknown . Unexpected diversity has been uncovered in Achromatium populations and it is now clear that the organism routinely described as Achromatium oxaliferum actually comprises several distinct Achromatium spp. Biofizika, 2000 Sep-Oct, 45(5), 864 - 9 {Reducing centers on the surface of Escherichia coli bacteria and their role in copper-induced plasma membrane permeability}; Lebedev VS et al.; The reducing properties of Escherichia coli and their role in the induction of nonselective cationic permeability of plasma membrane by the action of Cu2+ ions were studied . The ability of cells to reduce exogenous dithiopyridine was shown to be maximal in freshly collected culture and to decrease upon starvation or exhaustion of bacteria by dinitrophenol, in the presence of other oxidants of cell thiols in the medium, and after the disturbance of the barrier properties of membrane by tetrachloracetic acid or butanol . The alkylation of cell thiols accessible for N-ethyl maleimide completely disrupted the reducing activity of bacteria . These data are consistent with the conception that the reduction of dithiopyridine and Cu2+ ions by bacteria occurs on the thiol-containing centers of the cell surface, which are continuously reduced by the transfer of cell reducing equivalents from the inner to the outer surface of plasma membrane . The analysis of data on the effect of external oxidizing and reducing agents on the copper-induced plasmolysis of bacteria showed that the induction of membrane permeability by the action of copper can occur upon interaction with critical targets on the surface of Cu+ ions formed in the periplasmic space in the reaction of Cu2+ ions with reducing centers. Membr Cell Biol, 2000, 14(2), 173 - 80 The dipyridamole effect on the photoactive bacteriochlorophyll interaction with quinone acceptors in reaction centers of purple bacteria; Churbanova IYu et al.; The effect of Dipyridamole (10(-6)-10(-3) M) on the photomobilized electron transport in the system of quinone acceptors Q(A)-Q(B) of isolated photosynthetic reaction centers of Rhodobacter sphaeroides and on its temporary stabilization on Q(B) was studied . Depending on the type of the detergent present in the reaction center (lauryl dimethylamine oxide, Triton X-100, sodium dodecyl sulfate, and sodium cholate), dipyridamole could increase the time of the electron transfer to Q(B) . The dipyridamole effect on the efficiency of the electron stabilization on Q(B) for reaction centers with different detergents was revealed in slowing down the process of dark reduction of photoactive bacteriochlorophyll from Q(B) at initial concentrations of added dipyridamole (10(-6)-10(-5) M) with following acceleration of the process at the dipyridamole concentrations of 10(-4)-10(-3) M . The pH lowering from 6.8-7.0 to 5.9-6.0 increased the dipyridamole effect . The possibility of the dipyridamole effect on the structural-dynamic state of the reaction center complex, including its hydrogen bond system, which influences the studied parameters of functional activity, is suggested. Med Hypotheses, 2000 Dec, 55(6), 502 - 6 Single and multiple cholesterol gallstones and the influence of bacteria; Vitetta L et al.; Single and multiple cholesterol gallstones constitute at least 80% of the gallstone population observed at cholecystectomy in Western countries . While supersaturation of bile with cholesterol is necessary for gallstone growth, the kinetic determinant of crystal nucleation is perhaps the critical factor leading to the incidence of gallstones . Nucleation involves aggregation of nidus-forming materials like pigment precipitates and mucus proteins . In combination with cholesterol precipitates and crystal formation, gallstone propagation is enhanced . Bacterial species may augment the process of nucleation and gallstone growth by contributing specific enzyme activities resulting in the formation of insoluble precipitates in bile, or by acting as a nidus upon which the deposition of cholesterol crystals may initiate gallstone formation . The utilization of Raman microscopic techniques permits detailed mapping of the distribution of the gallstone components leading to identification and characterization of the site of nucleation . This, when coupled to molecular genetic tools such as PCR DNA amplification, would permit elucidation of the role of bacteria in vivo gallstone propagation mechanisms . Protein Expr Purif, 2000 Dec, 20(3), 435 - 43 Coexpression of proteins in bacteria using T7-based expression plasmids: expression of heteromeric cell-cycle and transcriptional regulatory complexes; Johnston K et al.; This report describes the development and application of a dual vector coexpression system for the overproduction of heteromeric cell cycle and transcriptional regulatory protein complexes in bacteria . To facilitate these studies we constructed a T7-based expression plasmid, pRM1 that contains an origin of replication derived from p15A, and a gene encoding kanamycin resistance . This expression vector is compatible with ColE1-derived plasmids found in the pET family of T7 expression vectors, which encode ampicillin resistance . It also has the same multiple cloning sites as the pET- derived pRSET vector, allowing easy shuttling between the two expression vectors . Cotransformation of the pRM1 and pET-derived expression vectors into an Escherichia coli strain such as BL21(DE3) results in a significant level of coexpression of heteromeric protein complexes . We demonstrate the applicability of combining the pRM1 and pET-derived vectors for the coexpression of cell cycle regulatory components, pRB/E7 and pRB/E1a, and the transcriptional regulatory complexes, SRF/SAP-1 and SRF/Elk-1 . We further use the pRB/E1a complex to demonstrate that these coexpressed complexes can be purified to homogeneity for further studies . Use of the pRM1 vector in combination with the pET-derived vectors should be generally applicable for the large-scale coexpression and purification of a wide variety of heteromeric protein complexes for biochemical, biophysical, and structural studies . J Gastrointest Surg, 2000 Sep-Oct, 4(5), 547 - 53 Pigment gallstone pathogenesis: slime production by biliary bacteria is more important than beta-glucuronidase production; Stewart L et al.; Pigment stones are thought to form as a result of deconjugation of bilirubin by bacterial beta-glucuronidase, which results in precipitation of calcium bilirubinate . Calcium bilirubinate is then aggregated into stones by an anionic glycoprotein . Slime (glycocalyx), an anionic glycoprotein produced by bacteria causing foreign body infections, has been implicated in the formation of the precipitate that blocks biliary stents . We previously showed that bacteria are present within the pigment portions of gallstones and postulated a bacterial role in pigment stone formation through beta-glucuronidase or slime production . Ninety-one biliary bacterial isolates from 61 patients and 12 control stool organisms were tested for their production of beta-glucuronidase and slime . The average slime production was 42 for biliary bacteria and 2.5 for stool bacteria (P <0.001) . Overall, 73% of biliary bacteria and 8% of stool bacteria produced slime (optical density >3) . In contrast, only 38% of biliary bacteria produced beta-glucuronidase . Eighty-two percent of all patients, 90% of patients with common bile duct (CBD) stones, 100% of patients with primary CBD stones, and 93% of patients with biliary tubes had one or more bacterial species in their stones that produced slime . By comparison, only 47% of all patients, 60% of patients with CBD stones, 62% of patients with primary CBD stones, and 50% of patients with biliary tubes had one or more bacteria that produced beta-glucuronidase . Most biliary bacteria produced slime, and slime production correlated better than beta-glucuronidase production did with stone formation and the presence of biliary tubes or stents . Patients with primary CBD stones and biliary tubes had the highest incidence of slime production . These findings suggest that bacterial slime is important in gallstone formation and the blockage of biliary tubes. Infection, 2000 Sep, 28(5), 301 - 4 Phagocytosis of periodontopathogenic bacteria by crevicular granulocytes is depressed in progressive periodontitis; Eick S et al.; BACKGROUND: The aim of this study was to examine crevicular polymorphonuclear neutrophils (PMN) of patients with rapidly progressive periodontitis (RPP) for their in vitro phagocytic activity and intracellular killing of Porphyromonas gingivalis ATCC 33277 and two strains of Actinobacillus actinomycetemcomitans (NCTC 9710 - type strain and Tanner FDC 44 - leukotoxin producing strain) . PATIENTS AND METHODS: 18 patients with RPP and nine healthy controls were included in the study . Phagocytosis and intracellular killing were assessed by fluorescence microscopy after staining with acridine orange . The percentage of phagocytosing PMN was determined.The phagocytic cells were then separated into two groups; those containing < 10 phagocytosed bacteria and those containing > 10 bacteria.The percentage of PMN containing viable bacteria was also determined . RESULTS: The leukotoxic A . actinomycetemcomitans strain was phagocytosed to a lesser degree than the corresponding type strain.The number of phagocytosing cells obtained from the RPP patients did not differ from the controls . However, in healthy subjects there were more phagocytes with more than ten ingested P . gingivalis than in RPP patients.The intracellular killing was diminished in the periodontitis group for P . gingivalis and for both A . actinomycetemcomitans strains . CONCLUSION: The PMN of patients with RPP show deficiencies in phagotcytic activity and in the intracellular killing or peridontopathogenic bacteria. Genome Inform Ser Workshop Genome Inform, 1998, 9, 13 - 21 Construction of the gyrB Database for the Identification and Classification of Bacteria; Kasai H et al.; Nucleotide sequences of small-subunit rRNA (16S rRNA) are most commonly used for the identification and characterization of bacteria and their complex communities . However, 16S rRNA evolves slowly and is often not very convenient to resolve bacterial strains at the species level . We have therefore attempted to develop a rapid and more convenient system for bacterial identification using the gyrB gene sequences . We chose the gyrB gene, because (i) it is rarely transmitted horizontally, (ii) its molecular evolution rate is higher than that of 16S rRNA, and (iii) the gene is distributed ubiquitously among bacterial species . We PCR-amplified the 1.2 kb-long gyrB segments from about 1,000 bacterial species by using degenerate primers and determined their nucleotide sequences . The resultant data have been assembled into the gyrB database accessible via WWW. Mol Microbiol, 2000 Nov, 38(3), 650 - 7 DNA-independent transport of plasmid primase protein between bacteria by the I1 conjugation system; Wilkins BM et al.; The ColIb-P9 (IncI1)-encoded conjugation system supports transfer of the plasmid T-strand plus hundreds of molecules of the Sog polypeptides determined by the plasmid primase gene . Here, we report that Sog primase is abundantly donated to the recipient cell from cells carrying a non-transferable ColIb plasmid deleted of the nic site essential for DNA export . Such DNA-independent secretion of Sog primase is typical of authentic conjugation, both in being blocked when the recipient cell specifies the entry exclusion function of ColIb and in requiring the thin I1 pilus encoded by the ColIb pil system under the mating conditions used . It is proposed that Sog polypeptides form a complex with the ColIb T-strand during conjugation and aid DNA transport through processive secretion of the proteins into the recipient cell . Functional and genetic relationships between the ColIb conjugation system and other type IV secretion pathways are discussed. Can J Microbiol, 2000 Oct, 46(10), 927 - 37 Methanogens and sulfate-reducing bacteria in oil sands fine tailings waste; Holowenko FM et al.; In the past decade, the large tailings pond (Mildred Lake Settling Basin) on the Syncrude Canada Ltd . lease near Fort McMurray, Alta., has gone methanogenic . Currently, about 60%-80% of the flux of gas across the surface of the tailings pond is methane . As well as adding to greenhouse gas emissions, the production of methane in the fine tailings zone of this and other settling basins may affect the performance of these settling basins and impact reclamation options . Enumeration studies found methanogens (10(5)-10(6) MPN/g) within the fine tailings zone of various oil sands waste settling basins . SRB were also present (10(4)-10(5) MPN/g) with elevated numbers when sulfate was available . The methanogenic population was robust, and sample storage up to 9 months at 4 degrees C did not cause the MPN values to change . Nor was the ability of the consortium to produce methane delayed or less efficient after storage . Under laboratory conditions, fine tailings samples released 0.10-0.25 mL CH4 (at STP)/mL fine tailings . The addition of sulfate inhibited methanogenesis by stimulating bacterial competition. Hautarzt, 2000 Sep, 51(9), 655 - 60 {Reduction of colonization of new mattresses with bacteria, moulds and house dust mites by complete mattress covers}; Pitten FA et al.; BACKGROUND AND OBJECTIVE: We investigated if the colonisation of new mattresses with house dust mites, bacteria, and fungi could be reduced by using synthetic mattress covers as compared to common cotton covers . PATIENTS/METHODS: 84 healthy volunteers were assigned to two groups . Group A (n = 43) received the cotton covers, group B (n = 41) the synthetic covers which were made of a polyester microfaser with a polyurethane surface layer (Pro-Tex, Germed, Schwarzenbek, Germany) . RESULTS: The mite antigen concentration after six months was significantly lower in group B . Three months after the start of the study counts of bacteria and moulds were significantly higher in group A compared to group B . CONCLUSIONS: It can be recommended that patients suffering from an allergy to mites or moulds may reduce their domestic allergen exposure by using the synthetic mattress covers tested in this study . Since cotton covers are very likely to become colonised by bacteria and moulds, they must be cleaned periodically (at least every 2nd-3d month). Transfus Med Rev, 2000 Oct, 14(4), 302 - 11 Blood group associations with parasites, bacteria, and viruses; Moulds JM et al.; Although recent investigations into the human blood groups have proceeded mainly at the molecular level, the RBC remains an exquisite model to study the expression of various genes and their related proteins . Although DNA may be informative, it may not always give meaningful information regarding protein expression on cell surfaces, which is where binding occurs . Because of their easy accessibility, RBCs will continue to be used as a major tool in the investigation of the causative agents for disease, whether they be viral, bacterial, or parasitic in nature. J Bacteriol, 2000 Nov, 182(22), 6499 - 502 Evolutionary conservation of methyl-accepting chemotaxis protein location in Bacteria and Archaea; Gestwicki JE et al.; The methyl-accepting chemotaxis proteins (MCPs) are concentrated at the cell poles in an evolutionarily diverse panel of bacteria and an archeon . In elongated cells, the MCPs are located both at the poles and at regions along the length of the cells . Together, these results suggest that MCP location is evolutionarily conserved. Acta Biochim Pol, 2000, 47(2), 451 - 7 A new look at adaptive mutations in bacteria; Janion C; This is a short survey of the adaptive mutation processes that arise in non- or slowly-dividing bacterial cells and includes: (i) bacterial models in which adaptive mutations are studied; (ii) the mutagenic lesions from which these mutations derive; (iii) the influence of DNA repair processes on the spectrum of adaptive mutations . It is proposed that in starved cells, likely as during the MFD phenomenon, lesions in tRNA suppressor genes are preferentially repaired and no suppressor tRNAs are formed as a result of adaptive mutations . Perhaps the most provocative proposal is (iv) a hypothesis that the majority of adaptive mutations are selected in a pre-apoptotic state where the cells are either mutated, selected, and survive, or they die. Membr Cell Biol, 2000, 14(1), 37 - 45 Effect of dipyridamole on the recombination kinetics between photooxidized bacteriochlorophyll and photoreduced primary quinone in reaction centres of purple bacteria; Knox PP et al.; The action of dipyridamole (DIP) on dark recombination between the photooxidized special pair bacteriochlorophyll BChl2+ and reduced primary quinone acceptor Q(A)- in the reaction centres (RCs) of the bacteria Rhodobacter sphaeroides was studied in the presence of different detergents (LDAO, Triton X-100, sodium cholate, sodium dodecyl sulfate) . DIP accelerated this reaction approximately 4-5-fold . In RCs with the extracted H-subunit, the effect of DIP was observed at lower concentrations . The possibility of modification of the RC structure-dynamic state by DIP (including changes in RC hydrogen bonds) is proposed . The modification obviously disturbs the processes of the long-life electrostatic stabilization of Q(A)-. FEMS Microbiol Ecol, 2000 Oct 1, 34(1), 57 - 62 Geostatistical analysis of the distribution of NH(4)(+) and NO(2)(-)-oxidizing bacteria and serotypes at the millimeter scale along a soil transect; Grundmann GL et al.; Soil is known to be heterogeneous for different activities at several spatial scales . Most studies have focused on macro- and meso-scales but micro-scales are rarely addressed . Hence, the spatial structure of NH(4)(+)- and NO(2)(-)-oxidizers and of various serotypes of the latter was studied along two transects of approximately 10 cm, with two micro-samples taken from each millimeter . The presence of NH(4)(+)- and NO(2)(-)-oxidizers in a micro-sample was detected using colorimetric tests for the presence or absence of NO(2)(-) in cultures of the micro-samples . Geostatistics was used to determine the range of spatial influence of the bacterial types . For both types, semi-variograms indicated a non-random spatial pattern . The spatial dependence ranged from 2 to 4 mm for NO(2)(-)- and NH(4)(+)-oxidizers respectively, and the two bacterial types were not independently spatially located . Among the six serotypes of NO(2)(-)-oxidizers, only one exhibited a spatial dependence . The existence of a spatial structure at the millimeter scale suggests that micro-scale sampling should be employed for soil studies . Therby, data on bacterial populations and activities can be referred to a spatial scale which is meaningful to these organisms. Biotechnol Bioeng, 2000 Dec 5, 70(5), 533 - 43 Ethanol utilization by sulfate-reducing bacteria: an experimental and modeling study; Nagpal S et al.; A mixed culture of sulfate-reducing bacteria containing the species Desulfovibrio desulfuricans was used to study sulfate-reduction stoichiometry and kinetics using ethanol as the carbon source . Growth yield was lower, and kinetics were slower, for ethanol compared to lactate . Ethanol was converted into acetate and no significant carbon dioxide production was observed . A mathematical model for growth of sulfate-reducing bacteria on ethanol was developed, and simulations of the growth experiments on ethanol were carried out using the model . The pH variation due to sulfate reduction, and hydrogen sulfide production and removal by nitrogen sparging, were examined . The modeling study is distinct from earlier models for systems using sulfate-reducing bacteria in that it considers growth on ethanol, and analyzes pH variations due to the product-formation reactions . Biofizika, 2000 Jul-Aug, 45(4), 648 - 53 {Effect of dipyridamole on recombination of photooxidized bacteriochlorophylla and photoreduced primary quinone in reactive centers of purple bacteria and degradation of form M412 of bacteriorhodopsin}; Zakharov NL et al.; It is shown that the addition of dipyridamole (2,6-bis(diethanolamino)-4,8-dipiperidinopyrimido{5,4d}py rim idine) (up to 10(-4) M) leads to a drastic acceleration of the dark recombination reaction between photooxidized bacteriochlorophyll and photoreduced primary quinone in reaction centers of Rhodobacter sphaeroides . The value of the acceleration is similar to that registered under cryogenic temperatures . The extent of the effect of dipyridamole derivatives depended on their structure . In wild-type bacteriorhodopsin and D96N mutant, dipyridamole slowed down the Schiff base reprotonation (the kinetics of M412 form decay was registered) . It is suggested that dipyridamole can influence the structural and dynamic state of membrane proteins by affecting the system of their hydrogen-bonds and thus modify electron and proton transport processes. FEMS Microbiol Lett, 2000 Nov 1, 192(1), 145 - 52 Localization of Legionella bacteria within ribosome-studded phagosomes is not restricted to Legionella pneumophila; Gerhardt H et al.; In this report, we investigate the intracellular fate of selected members of the genus Legionella within the monocytic cell line Mono Mac 6 cells . By means of electron microscopy and immunocytochemistry, we could show that Legionella pneumophila as well as Legionella longbeachae are able to induce ribosome-studded phagosomes which associate with the rough endoplasmic reticulum (RER), whereas Legionella micdadei remains to be located within smooth phagosomes but also shows signs of RER association . In addition, we could demonstrate a remarkable correlation between the phagosome type and the morphological phenotype of intracellular bacteria: within ribosome-studded phagosomes, bacteria generally lacked the outer coat of low electron density whereas bacteria within the smooth phagosomes still possessed this outer coat . The virulence factors responsible for inhibition of phagosome maturation and their distribution within the genus Legionella as well as the biological significance of the morphological difference of bacteria within smooth and ER-associated phagosomes remain to be investigated. Protein Expr Purif, 2000 Oct, 20(1), 37 - 44 Expression of functional soluble human alpha-globin chains of hemoglobin in bacteria; Adachi K et al.; Individual, soluble human alpha-globin chains were expressed in bacteria with exogenous heme and methionine aminopeptidase . The yields of soluble alpha chains in bacteria were comparable to those of recombinant non-alpha chains expressed under the same conditions . Molecular mass and gel-filtration properties of purified recombinant alpha chains were the same as those of authentic human alpha chains . Biochemical and biophysical properties of isolated alpha chains were identical to those of native human alpha chains as assessed by UV/vis, circular dichroism (CD), and nuclear magnetic resonance (NMR) spectroscopy which contrasts with previous results of refolded precipitated alpha chains made in the presence of heme in vitro (M . T . Sanna et al., J . Biol . Chem . 272, 3478-3486, 1997) . Mixtures of purified, soluble recombinant alpha-globin and native beta-globin chains formed heterotetramers in vitro, and oxygen- and CO-binding properties as well as the heme environment of the assembled tetramers were experimentally indistinguishable from those of native human Hb A . UV/vis, CD, and NMR spectra of assembled Hb A were also the same as those of human Hb A . These results indicate that individual expressed alpha chains are stable in bacteria and fold properly in vivo and that they then can assemble with free beta chains to form hemoglobin heterotetramers in vivo as well as in vitro . Infect Immun, 2000 Nov, 68(11), 6496 - 504 Transmission electron microscopic demonstration of phagocytosis and intracellular processing of segmented filamentous bacteria by intestinal epithelial cells of the chick ileum; Yamauchi KE et al.; Segmented filamentous bacteria (SFB) are autochthonous bacteria colonizing the ileum of many young animals by attaching to intestinal epithelial cells . These nonpathogenic bacteria strongly stimulate the mucosal immune system and induce intestinal epithelial cells to express major histocompatibility complex class II molecules . We tried to discover whether SFB are phagocytized and intracellularly processed by the host cells, which is indicative of antigen processing . The middle part of the ileum was extracted from 10- and 20-day-old broiler chicks (Gallus gallus domesticus) . Samples were processed and examined by scanning and transmission electron microscopy (SEM and TEM, respectively) . In SEM, no, few, medium, and dense SFB colonization levels were classified . In TEM of cells from animals with medium or dense SFB colonization levels, we could observe extracellular particles ranging from those only indenting the cell membrane to particles found in the cytoplasmatic area beyond the terminal web . These particles had a structural similarity with SFB that were floating freely in the intestinal lumen . Furthermore, we observed unlacing of the membrane and septum surrounding the extracellular particles and their incorporation into host cytoplasmatic components, which strongly suggests that these particles are phagocytized and intracellularly processed SFB . This conclusion is supported by TEM analysis of samples with no or few SFB, in which we failed to find these characteristic morphologies . The phagocytosis process described here could be an important trigger for the stimulating effect of SFB on the mucosal immune system. FEBS Lett, 2000 Sep 1, 480(2-3), 73 - 8 Pigment-protein architecture in the light-harvesting antenna complexes of purple bacteria: does the crystal structure reflect the native pigment-protein arrangement? Leupold D, Voigt B, Beenken W, Stiel H. Structural analysis of crystallized peripheral (LH2) and core antenna complexes (LH1) of purple bacteria has revealed circular aggregates of high rotational symmetry (C8, C9 and C16, respectively) . Quantum-chemical calculations indicate that in particular the waterwheel-like arrangements of pigments should show characteristic structure-sensitive spectroscopic behavior in the near infrared absorption region . Laser-spectroscopic data obtained with non-crystallized, isolated LH2 of Rhodospirillum molischianum are in line with a highly symmetric (C8) circular aggregate, but deviations have been found for LH2 of Rhodobacter sphaeroides and Rhodopseudomonas acidophila . For both the latter, C-shaped incomplete circular aggregates (as seen only recently in electron micrographs of crystallized LH1-reaction center complexes) may be a suitable preliminary model. Gene, 2000 Sep 19, 255(2), 419 - 24 Purple acid phosphatases from bacteria: similarities to mammalian and plant enzymes; Schenk G et al.; Mammalian and plant purple acid phosphatases have similar active site structures despite low sequence identity (<20%) . Although no bacterial enzyme has been purified, a sequence database search revealed that genes that could encode potential purple acid phosphatases may be restricted to a small number of organisms (i.e . myco- and cyanobacteria) . Analysis of their deduced amino acid sequences and predicted secondary structures indicates that the cyanobacterial enzyme is similar to both the mammalian and the recently discovered low-molecular-weight plant purple acid phosphatases, while the mycobacterial enzyme is homologous to the fungal and high-molecular-weight plant purple acid phosphatases . Homology models indicate that both bacterial proteins appear to be similar to mammalian purple acid phosphatases in the immediate vicinity of the active site . It is likely that these enzymes act as Fenton-type catalysts in order to prevent damage caused by reactive oxygen species generated by invaded host cells (M . tuberculosis) or by the light-harvesting complex (Synechocystis sp.). Biophys J, 2000 Oct, 79(4), 2105 - 20 Exciton dynamics in the chlorosomal antennae of the green bacteria Chloroflexus aurantiacus and Chlorobium tepidum; Prokhorenko VI et al.; The energy transfer processes in isolated chlorosomes from green bacteria Chlorobium tepidum and Chloroflexus aurantiacus have been studied at low temperatures (1.27 K) by two-pulse photon echo and one-color transient absorption techniques with approximately 100 fs resolution . The decay of the coherence in both types of chlorosomes is characterized by four different dephasing times stretching from approximately 100 fs up to 300 ps . The fastest component reflects dephasing that is due to interaction of bacteriochlorophylls with the phonon bath, whereas the other components correspond to dephasing due to different energy transfer processes such as distribution of excitation along the rod-like aggregates, energy exchange between different rods in the chlorosome, and energy transfer to the base plate . As a basis for the interpretation of the excitation dephasing and energy transfer pathways, a superlattice-like structural model is proposed based on recent experimental data and computer modeling of the Bchl c aggregates (1994 . Photosynth . Res . 41:225-233.) This model predicts a fine structure of the Q(y) absorption band that is fully supported by the present photon echo data. Ecotoxicol Environ Saf, 2000 Oct, 47(2), 186 - 94 Comparison of four chronic toxicity tests using algae, bacteria, and invertebrates assessed with sixteen chemicals; Radix P et al.; The performances of four chronic toxicity tests, comprising the Daphnia magna 21-day (d) (crustacean), Brachionus calyciflorus 2-d (rotifer), Pseudokirchneriella subcapitata 72-h (green algae), and the Microtox chronic 22-h (bacteria) tests, were compared . Sixteen chemicals with toxicity covering 6 orders of magnitude were studied . Very high correlations were found between the NOEC/EC(10) Pseudokirchneriella 72-h, NOEC/EC(10) Brachionus 2-d, and the NOEC Daphnia 21-d tests . The toxicological response of rotifers and microalgae were within the same order of magnitude as the response of Daphnia in 80% of cases (13/16 chemicals) . The Microtox chronic test also anticipated the overall results of the Daphnia 21-d test, but the prediction was rather imprecise, compared with microalgae and rotifers . The test measuring the algal growth inhibition of P . subcapitata after 72h was the most sensitive bioassay . Toxicity on microalgae after 72h could be estimated after 5h by measuring either the direct fluorescence of either photosynthetic pigments or fluorescein diacetate in 56 and 43% of cases, respectively . The median value of the ratio between EC(10) and EC(50) was 3.75, 2, and 1.5 with the algae, the rotifers, and the bacteria, respectively . Annu Rev Microbiol, 2000, 54, 681 - 708 DNA segregation in bacteria; Gordon GS et al.; Segregation of DNA in bacterial cells is an efficient process that assures that every daughter cell receives a copy of genomic and plasmid DNA . In this review, we focus primarily on observations in recent years, including the visualization of DNA and proteins at the subcellular level, that have begun to define the events that separate DNA molecules . Unlike the process of chromosome segregation in higher cells, segregation of the bacterial chromosome is a continuous process in which chromosomes are separated as they are replicated . Essential to separation is the initial movement of sister origins to opposite ends of the cell . Subsequent replication and controlled condensation of DNA are the driving forces that move sister chromosomes toward their respective origins, which establishes the polarity required for segregation . Final steps in the resolution and separation of sister chromosomes occur at the replication terminus, which is localized at the cell center . In contrast to the chromosome, segregation of low-copy plasmids, such as Escherichia coli F, P1, and R1, is by mechanisms that resemble those used in eukaryotic cells . Each plasmid has a centromere-like site to which plasmid-specified partition proteins bind to promote segregation . Replication of plasmid DNA, which occurs at the cell center, is followed by rapid partition protein-mediated separation of sister plasmids, which become localized at distinct sites on either side of the division plane . The fundamental similarity between chromosome and plasmid segregation-placement of DNA to specific cell sites-implies an underlying cellular architecture to which both DNA and proteins refer. Appl Environ Microbiol, 2000 Oct, 66(10), 4532 - 5 Pacific Northwest marine sediments contain ammonia-oxidizing bacteria in the beta subdivision of the Proteobacteria; Nold SC et al.; The diversity of ammonia-oxidizing bacteria in aquatic sediments was studied by retrieving ammonia monooxygenase and methane monooxygenase gene sequences . Methanotrophs dominated freshwater sediments, while beta-proteobacterial ammonia oxidizers dominated marine sediments . These results suggest that gamma-proteobacteria such as Nitrosococcus oceani are minor members of marine sediment ammonia-oxidizing communities. Appl Environ Microbiol, 2000 Oct, 66(10), 4518 - 22 Use of combined microautoradiography and fluorescence in situ hybridization to determine carbon metabolism in mixed natural communities of uncultured bacteria from the genus Achromatium; Gray ND et al.; Combined microautoradiography and fluorescence in situ hybridization (FISH) was used to investigate carbon metabolism in uncultured bacteria from the genus Achromatium . All of the Achromatium species identified in a freshwater sediment from Rydal Water, Cumbria, United Kingdom, which were distinguishable only by FISH, assimilated both {(14)C}bicarbonate and {(14)C}acetate . This extends previous findings that Achromatium spp . present at another location could only utilize organic carbon sources . Achromatium spp., therefore, probably exhibit a range of physiologies, i.e., facultative chemolithoautotrophy, mixotrophy, and chemoorganoheterotrophy, similar to other large sulfur bacteria (e.g., Beggiatoa spp.). Mikrobiologiia, 2000 Jul-Aug, 69(4), 483 - 7 {Destruction of chlorinated derivatives of phenol: ortho-chlorophenol, para-chlorophenol, and 2,4-dichlorophenoxyacetic acid by bacteria communities in anaerobic sludge}; Berestovskaia IuIu et al.; The bacterial community of anaerobic sludge could degrade ortho-chlorophenol, para-chlorophenol, and 2,4-dichlorophenoxyacetic acid at concentrations as high as 100 mg/l . The time needed for the degradation of a given chlorinated phenol derivative increased 1.5- to 2-fold upon a twofold increase in its concentration (from 50 to 100 mg/l) . The duration of the adaptation period depended on the compound studied and on its concentration . The degradation of 2,4-dichlorophenoxyacetic acid proceeded via 2,4-dichlorophenol and p-chlorophenol as intermediates; the degradation of o-chlorophenol occurred with the formation of phenol . The dynamics of p-chlorophenol degradation and chloride ion accumulation were studied. Biochem Biophys Res Commun, 2000 Sep 16, 276(1), 64 - 70 ppGpp-dependent leuO expression in bacteria under stress; Fang M et al.; Despite the known potential transcription regulatory role of leuO gene product, LeuO, the condition when leuO expresses during bacterial growth cycle remains unclear . Mechanistically, leuO expression was shown to be part of promoter relay mechanism, however, the factor(s) responsible for the regulation of leuO expression is not known . Combining Northern and Western results, we demonstrate in the present communication that leuO expression is normally low and enhanced when bacteria are in transition from exponential growth to stationary phase . The stationary phase-associated leuO expression is ppGpp dependent and rpoS (varsigma(s) factor) independent . Biotechnol Bioeng, 2000 Nov 20, 70(4), 464 - 6 High density cultivation of two strains of iron-oxidizing bacteria through reduction of ferric iron by intermittent electrolysis; Matsumoto N et al.; Electrolytic cultivation was applied to Leptospirillum ferrooxidans strains P3A and CF27, which use ferrous iron to respire aerobically . Ferrous iron was supplied to the bacteria by intermittent electrolytic reduction of ferric iron as electron shuttle using an electrode . The yield of L . ferrooxidans and strain CF27 reached 20- and 50-fold, respectively, higher density than were achievable yields without electrolysis . The time required to obtain high density depended not on the growth ratio, but rather on the original growth rate of each strain . Proc Natl Acad Sci U S A, 2000 Oct 10, 97(21), 11397 - 402 Genes identified by an expression screen of the vector mosquito Anopheles gambiae display differential molecular immune response to malaria parasites and bacteria; Oduol F et al.; We performed a gene expression screen of the entire transcriptome of the major African malaria vector Anopheles gambiae for immune response genes in adult female mosquitoes, which is the developmental stage infected by malaria parasites . Mosquitoes were immune-stimulated for subtractive cloning by treatment with bacterial lipopolysaccharide, a potent and general elicitor of the innate immune response, and by injury . The screen yielded a highly enriched cDNA library in which more than half of the clones were immune responsive . In this paper, we describe 23 immune-regulated genes, including putative protease inhibitors, serine proteases, regulatory molecules, and a number of genes without known relatives . A molecule related to the protease inhibitor alpha-2-macroglobulin responded strongly to malaria parasite infection, but displayed little or no response to bacteria, whereas other genes exhibited the inverse pattern . These results indicate that the insect immune system discriminates between molecular signals specific to infection with bacteria and malaria parasites. Biochim Biophys Acta, 2000 Aug 15, 1459(2-3), 370 - 82 Biogenesis of iron-sulfur proteins in eukaryotes: a novel task of mitochondria that is inherited from bacteria; Muhlenhoff U et al.; Fe/S clusters are co-factors of numerous proteins with important functions in metabolism, electron transport and regulation of gene expression . Presumably, Fe/S proteins have occurred early in evolution and are present in cells of virtually all species . Biosynthesis of these proteins is a complex process involving numerous components . In mitochondria, this process is accomplished by the so-called ISC (iron-sulfur cluster assembly) machinery which is derived from the bacterial ancestor of the organelles and is conserved from lower to higher eukaryotes . The mitochondrial ISC machinery is responsible for biogenesis iron-sulfur proteins both within and outside the organelle . Maturation of the latter proteins involves the ABC transporter Atm1p which presumably exports iron-sulfur clusters from the organelle . This review summarizes recent developments in our understanding of the biogenesis of iron-sulfur proteins both within bacteria and eukaryotes. Proc Natl Acad Sci U S A, 2000 Sep 26, 97(20), 10808 - 13 Femtosecond dynamics of the forbidden carotenoid S1 state in light-harvesting complexes of purple bacteria observed after two-photon excitation; Walla PJ et al.; Time-resolved excited-state absorption intensities after direct two-photon excitation of the carotenoid S(1) state are reported for light-harvesting complexes of purple bacteria . Direct excitation of the carotenoid S(1) state enables the measurement of subsequent dynamics on a fs time scale without interference from higher excited states, such as the optically allowed S(2) state or the recently discovered dark state situated between S(1) and S(2) . The lifetimes of the carotenoid S(1) states in the B800-B850 complex and B800-B820 complex of Rhodopseudomonas acidophila are 7+/-0.5 ps and 6+/-0.5 ps, respectively, and in the light-harvesting complex 2 of Rhodobacter sphaeroides approximately 1.9+/-0.5 ps . These results explain the differences in the carotenoid to bacteriochlorophyll energy transfer efficiency after S(2) excitation . In Rps . acidophila the carotenoid S(1) to bacteriochlorophyll energy transfer is found to be quite inefficient (phi(ET1) <28%) whereas in Rb . sphaeroides this energy transfer is very efficient (phi(ET1) approximately 80%) . The results are rationalized by calculations of the ensemble averaged time constants . We find that the Car S(1) --> B800 electronic energy transfer (EET) pathway ( approximately 85%) dominates over Car S(1) --> B850 EET ( approximately 15%) in Rb . sphaeroides, whereas in Rps . acidophila the Car S(1) --> B850 EET ( approximately 60%) is more efficient than the Car S(1) --> B800 EET ( approximately 40%) . The individual electronic couplings for the Car S(1) --> BChl energy transfer are estimated to be approximately 5-26 cm(-1) . A major contribution to the difference between the energy transfer efficiencies can be explained by different Car S(1) energy gaps in the two species. Ukr Biokhim Zh, 2000 Mar-Apr, 72(2), 72 - 6 {Effect of thallium of ATP-ase activity and transmembrane potential in bacteria}; Gruzina TG et al.; Effect of thallium (TlNO3) on the ATPase activity and transmembrane potential (Dj) of bacteria with different levels of resistance to this metal has been studied . The hypothesis has been made that the resistance biochemical mechanism is based on the energy transformation systems in the cell. Nihon Hansenbyo Gakkai Zasshi, 2000 Jul, 69(2), 83 - 6 {Protective immunity against intracellular parasitic bacteria}; Mitsuyama M; Facultative intracellular bacteria are resistant to the killing mechanism inside macrophages by virtue of various escape mechanisms . Activation of macrophages by cytokines is the key event to overcome of bacterial escape in macrophages of the infected host . Generation of TH1 type of antigen-specific T cell is the essentially required for the macrophage activation . This short review summarizes the escape mechanism of activated macrophages and the mechanisms involved in the generation of TH1 cells. Microb Ecol, 2000 Jul, 40(1), 57 - 63 Substrate Concentration and Plasmid Transfer