Peptides, 1997, 18(9), 1295 - 9 Expression of rat pro cholecystokinin (CCK) in bacteria and in insect cells infected with recombinant baculovirus; Wang W et al.; Neuropeptide prohormones are generally not abundant in nature as they exits to be processed and contain sites which could be cleaved by a number of cellular proteases . In order to study the processing of prohormones in vitro it is necessary to produce them in quantity . Finding an expression system which produces intact prohormone has been a matter of trial and error . We report that intact rat pro CCK was produced with an amino-terminal His-Tag in e . coli, and it was secreted from sf9 and other insect cells infected with a recombinant baculovirus vector . The bacteria contained about 0.1 micrograms pro CCK/ml of cells . The High 5 insect cells produced 4.3 micrograms/ml medium (as determined by RIA), 10 times as much as sf9 or sf21 . Using a combination of ion exchange, gel filtration and HPLC, the insect cell protein was purified about 150 fold with a recovery of about 16% . The secreted insect cell pro CCK is tyrosine sulfated like its mammalian equivalent . Using these expression systems it is possible to produce significant (microgram to mg) quantities of pro CCK for immunologic, enzymatic and structural studies. Nature, 1997 Nov 27, 390(6658), 395 - 8 Test of synergistic interactions among deleterious mutations in bacteria; Elena SF et al.; Identifying the forces responsible for the origin and maintenance of sexuality remains one of the greatest unsolved problems in biology . The mutational deterministic hypothesis postulates that sex is an adaptation that allows deleterious mutations to be purged from the genome; it requires synergistic interactions, which means that two mutations would be more harmful together than expected from their separate effects . We generated 225 genotypes of Escherichia coli carrying one, two or three successive mutations and measured their fitness relative to an unmutated competitor . The relationship between mutation number and average fitness is nearly log-linear . We also constructed 27 recombinant genotypes having pairs of mutations whose separate and combined effects on fitness were determined . Several pairs exhibit significant interactions for fitness, but they are antagonistic as often as they are synergistic . These results do not support the mutational deterministic hypothesis for the evolution of sex. Curr Opin Genet Dev, 1997 Oct, 7(5), 582 - 8 Adaptation of gene expression in stationary phase bacteria; Ishihama A; In nature, bacteria can survive for long periods in non-growing stationary states . Some species of bacteria survive by forming spores but non-spore-forming bacteria, including Escherichia coli, survive in the stationary phase . Gross changes in morphology and physiology occur in the stationary-phase bacteria and concomitantly a state of increased resistance against various stresses is established . The stationary-phase adaptation of E . coli has only recently begun to be investigated at the molecular level. Zhonghua Wai Ke Za Zhi, 1996 Apr, 34(4), 201 - 4 {Extremity gangrene caused by rare co-infection of multiple bacteria: a case report}; Liu S et al.; Because of progressive infectious necrosis on right hand and forearm for 3 months and the necrosis on left mid-finger for 2 months, a girl patient, Yang Xiaoxia was admitted on 15th, Nov . 1994 . Systemic intoxicative symptom was slight and the necrotic tissue presented black scar . After 3 months treatment by application of multiple antibiotics, local dressing changes and an amputation of right froearm, the necrosis could not be stopped but keeping deteriorating . Through experts' consultation, systemic surpportive therapy, wide-spectrum antibiotics cilastatin sodium and complete debridement were adopted . One week later, the fresh surface of granulation tissue was seen, and skin grafting was performed . The wound healed 3 months later . After further rehabilitation, the left thumb, index and fifth finger showed normal function . A mechanical motional artificial limb was installed on right forearm and discharged . The deep necrotic tissue of left mid-finger was examined . Results of culture from several hospital presented 2 kinds of aerobic bacteria and 10 kinds of the anaerobic, of which, the names of 3 kinds are still unknown . Pathological examination showed chronic pyogenic necrotic infection, spreading from skin to deep muscles and interosseous membrane . And infiltration of eosinophilic granulocytes was found in the infectious region . CONCLUSION: This patients is progressive gangrene of the extremity caused by rare co-infection of multiple bacteria . The characteristics were slight systemic intoxicative symptom, local progressive necrosis and formation of black scar . By means of systemic surpportive therapy, application of wide-spectrum antibiotics cilastatin sodium, complete debridement and skin grafting, the patient was cured. Biochem Biophys Res Commun, 1997 Oct 29, 239(3), 769 - 74 A molecular aspect of symbiotic interactions between the weevil Sitophilus oryzae and its endosymbiotic bacteria: over-expression of a chaperonin; Charles H et al.; Specific proteins of symbiosis were analyzed by the comparison of two-dimensional electrophoresis protein patterns of symbiotic and aposymbiotic strains of the weevil Sitophilus oryzae . One protein was shown to be exclusively expressed in the aposymbiotic strain and three proteins, including a chaperonin, were characterized in the symbiotic strain pattern . The groE-like operon, encoding the two chaperonins groES and GroEL-like proteins of the endocytobiotes, was sequenced . It was found to be very similar to the groE operon of Escherichia coli (82% identity) . In vitro and ex vivo experiments of protein labelling demonstrated that almost 40% of the endocytobiote protein synthesis ex vivo is focused on the GroEL-like protein . Finally, we showed by northern blotting that heat shock at 38 degrees C results in groEL mRNA accumulation inside the endocytobiotes . This work supports the hypothesis that chaperonins could have an essential physiological function in the maintenance of the symbiotic association. Appl Environ Microbiol, 1997 Nov, 63(11), 4237 - 42 Numerical dominance of a group of marine bacteria in the alpha-subclass of the class Proteobacteria in coastal seawater; Gonzalez JM et al.; A cluster of marine bacteria within the alpha-3 subclass of the class Proteobacteria accounted for up to 28% of the 16S ribosomal DNA (rDNA) sequences in seawater samples from the coast of the southeastern United States . Two independent oligonucleotide probes targeting 16S rDNA of this "marine alpha" cluster indicate that the group dominates bacterioplankton communities in estuarine and nearshore regions of the southeastern U.S . coast . Marine alpha bacteria decline predictably in abundance with decreasing salinity along estuarine transsects and are not detectable in low-salinity (5%) or freshwater samples . Sequences of 16S rDNA obtained from seawater by PCR with one group-specific oligonucleotide as a primer confirm that the oligonucleotide targets only members of this phylogenetic cluster . Likewise, sequences of 16S rDNA obtained from seawater by PCR with several different pairs of nonspecific primers show an unusually high abundance of marine alpha sequences (52 to 84%) among the clones, which possibly indicates a PCR bias toward the group . Members of the marine alpha group were readily cultured from coastal seawater, accounting for 40% of the colonies isolated on low-nutrient marine agar, based on hybridizations with the group-specific 16S rDNA probe and on sequence analysis . This is the first description of a numerically dominant cluster of coastal bacteria, identified by molecular techniques, that can be readily cultured and studied in the laboratory. J Bacteriol, 1997 Nov, 179(21), 6764 - 8 Photoresponses of the purple nonsulfur bacteria Rhodospirillum centenum and Rhodobacter sphaeroides; Sackett MJ et al.; We have measured the photoresponse of two purple nonsulfur bacteria, Rhodobacter sphaeroides and Rhodospirillum centenum, under defined conditions in a light beam propagating at 90 degrees to the optical axis of the microscope . This beam presented cells with a steep gradient of intensity perpendicular to the direction of propagation and a shallow gradient in the direction of light propagation . R . centenum, a species that reverses to change direction, accumulated in the light beam, as expected for a "scotophobic" response, while R . sphaeroides, which stops rather than reverses, accumulated outside the light beam . We also compared the behavior of liquid-grown R . centenum, which swims by using a single polar flagellum, to that of surface-grown R . centenum, which swarms over agar by using many lateral flagella and has been shown to move as colonies toward specific wavelengths of light . When suspended in liquid medium, both liquid- and surface-grown R . centenum showed similar responses to the light gradient . In all cases, free-swimming cells responded to the steep gradient of intensity but not to the shallow gradient, indicating they cannot sense the direction of light propagation but only its intensity . In a control experiment, the known phototactic alga Chlamydamonas reinhardtii was shown to swim in the direction of light propagation. J Comp Pathol, 1997 Aug, 117(2), 185 - 90 Segmented filamentous bacteria in the bovine small intestine; Smith TM; Segmented filamentous bacteria (SFB) were observed in a 28-day-old calf, attached to the absorptive villi . Morphologically, they were similar to SFB described in other animal species . Because these organisms cannot be cultured, further characterization was not possible . The organisms were confined to the upper third of the absorptive villi and were not seen attached to the follicle-associated epithelium of the Peyer's patch, or observed in the caecum or colon . Although they were often associated with minor lesions, their pathological significance was doubtful . With this report, segmented filamentous bacteria have now been described in virtually all the commercially important livestock and poultry species, in other domestic animals, and in man. J Appl Microbiol, 1997 Oct, 83(4), 518 - 23 A quantitative PCR-ELISA for the rapid enumeration of bacteria in refrigerated raw milk; Gutierrez R et al.; We have developed a quantitative PCR-ELISA for the rapid enumeration of bacteria in refrigerated raw milk using primers designed from conserved regions in the 16S ribosomal RNA gene (rRNA) . The designed primers permitted the amplification of a 147 bp DNA fragment from a wide selection of bacteria which may grow in milk at refrigeration temperatures . Amplified PCR products generated using a digoxigenin-labelled primer were heat-denatured before being quantified by an enzyme-linked immunosorbent assay (ELISA) . A biotinylated probe immobilized onto streptavidin-coated microplates was used to capture the digoxigenin-labelled fragments that were detected with a peroxidase anti-digoxigenin conjugate . Subsequent enzymic conversion of substrate gave distinct absorbency differences when assaying milk samples containing bacteria in the range 10(3)-10(7) cfu ml-1 . The detection threshold for the PCR-ELISA assay developed in this work is 103 cfu ml-1. J Appl Microbiol, 1997 Oct, 83(4), 421 - 9 Diversity among aromatic hydrocarbon-degrading bacteria and their meta-cleavage genes; Daly K et al.; Sixty-one strains of bacteria capable of growth on 4-methyl benzoic acid (29 isolates) or naphthalene (32 isolates) as the sole source of carbon and energy were isolated from sediments and water samples from the River Tyne, UK . Random amplification of polymorphic DNA from genomic DNA extracted from the different strains demonstrated that 14 of the 4-methyl benzoate-degrading isolates were unique and the remainder fell into seven groups containing two or three isolates that produced identical banding patterns . Thirteen of the naphthalene-degrading isolates were unique and nine groups with two or three identical representatives encompassed all other isolates . Screening of the bacterial strains for the presence of genes homologous to xylE, nahC and bphC by polymerase chain reaction and dot blot hybridization demonstrated that most strains harboured xylE- and/or nahC-like genes and only a single isolate was found that did not harbour any of these genes . None of the isolates harboured bphC-like genes . It was concluded that, while considerable diversity existed in host strains isolated using a single simple enrichment procedure, the extradiol dioxygenase genes involved in aromatic ring cleavage, present in these strains, were conserved to a considerable degree. Exp Cell Res, 1997 Oct 10, 236(1), 43 - 50 Autofluorescence of live purple bacteria in the near infrared; Albrecht-Buehler G; We have developed a novel microscope with which to study the fluorescence of cells in the near-infrared region (lambda = 750-2500 nm) . For one of its first applications we report on the autofluorescence of live purple bacteria, Rhodospirillum rubrum, and suggest that the autofluorescent component is bacteriochlorophyll . The rapid fading of the autofluorescence of fixed bacteria and of purified bacteriochlorophyll suggests that the live bacteria are able to regenerate their pigment with a time constant of approximately 20 s. J Biol Chem, 1997 Oct 10, 272(41), 25623 - 7 A component of the chloroplast protein import apparatus functions in bacteria; Pang P et al.; Toc36 is a family of 44-kDa envelope polypeptides previously identified as components of the chloroplast protein import apparatus by virtue of their close physical proximity to translocating proteins . An indication of their function thus remains at large . A heterologous in vivo approach for studying the function of Toc36 was developed in this study by introducing a member of Toc36 into E . coli to assess its effect on bacterial protein translocation . The presence of Toc36 enhances the translocation of two bacterial periplasmic proteins in a manner resembling the chloroplast system . Translocation of the two bacterial periplasmic proteins was less sensitive to sodium azide, resembling more the azide-insensitive nature of the chloroplast protein import process . Mutated Toc36 proteins were not capable of causing the same effect as that observed for unaltered Toc36 . Toc36 was also capable of complementing bacterial strains with temperature-sensitive secA mutations that affected protein translocation . The combined results provide evidence that Toc36 plays a central role in the chloroplast protein translocation process. J Mol Biol, 1997 Sep 26, 272(3), 301 - 11 Characterization of nucleosome core particles containing histone proteins made in bacteria; Luger K et al.; The four core histone proteins, H2A, H2B, H3, and H4 of Xenopus laevis have been individually expressed in milligram quantities in Escherichia coli . The full-length proteins and the "trypsin-resistant" globular domains were purified under denaturing conditions and folded into histone octamers . Both intact and truncated recombinant octamers, as well as chicken erythrocyte octamer, were assembled into nucleosome core particles using a 146 bp defined-sequence DNA fragment from a 5 S RNA gene . The three types of core particles were characterized and compared by gel electrophoresis, DNase I cleavage, and tyrosine fluorescence emission during stepwise dissociation with increasing ionic strength . Nucleosome core particles containing native and mutant histones made in bacteria have facilitated its X-ray structure determination at 2.8 A resolution . Vestn Ross Akad Med Nauk, 1997, (7), 8 - 13 {Theoretical rationale for structure-genotoxicity relationships in the series of halogenated short-chain aliphatic compounds for mammals and bacteria}; Kharchevnikova NV et al.; Structure-genotoxicity relationships for mammals and structure-mutagenic activity relationships for bacterial were derived in the series of halogenated short-chain hydrocarbons and alcohols, by using the calculated quantum chemical parameters, namely the energy differences of frontier molecular orbitals and the electronic characteristics of the probable metabolites. Biosci Rep, 1997 Jun, 17(3), 335 - 42 How do bacteria avoid high oxygen concentrations? Zhulin IB, Johnson MS, Taylor BL. Bacteria, such as Escherichia coli and Azospirillum brasilense, avoid microenvironments with elevated oxygen concentrations, not by sensing reactive oxygen derivatives, but by sensing a metabolic down-shift that results from elevated oxygen levels . A novel protein, Aer, and the chemotaxis serine receptor, Tsr, have recently been identified as transducers for aerotaxis which monitor internal energy levels in the bacteria. Biotechnol Prog, 1997 Sep-Oct, 13(5), 519 - 23 Acetate-specific stress response in acetate-resistant bacteria: an analysis of protein patterns; Lasko DR et al.; Many metabolic byproducts have toxic effects on bacteria, and acetic acid is an excellent model for such molecules . The negative effects of acetate, which include decreased growth rates and specific productivities, appear for Escherichia coli at acetate concentrations lower than 5 g/L . Acetic acid bacteria, however, are naturally resistant to the detrimental effects of acetate in their surroundings; they remain active at acetate levels well over 40 g/L . This study investigated the response to acetate challenges by the naturally acetate-resistant bacteria Acetobacter aceti and Gluconobacter suboxydans to learn more about possible mechanisms of tolerance to otherwise toxic low molecular weight metabolites . Growth studies showed that the resistant bacteria grow more slowly in the presence of acetate but are not slowed nearly so much as is E . coli . In addition, two-dimensional gel electrophoresis (2DE) was applied to study the relative protein patterns of acetate-resistant bacteria during growth in the presence and absence of acetate . In each organism, growth in acetate-containing medium led to elevated levels of many stress response proteins . 2DE analysis of heat-shocked cultures was used to determine which were nonspecific . Elimination of those proteins that were also amplified following heat shock left only eight proteins, here designated acetate-specific stress proteins (Asps), which are overexpressed specifically in response to acetate . Three of these, AspA, AspB, and AspC, appear to be analogous in the two bacterial strains studied, based on their apparent pIs and molecular weights. Infect Immun, 1997 Oct, 65(10), 4243 - 9 Involvement of p21racA, phosphoinositide 3-kinase, and vacuolar ATPase in phagocytosis of bacteria and erythrocytes by Entamoeba histolytica: suggestive evidence for coincidental evolution of amebic invasiveness; Ghosh SK et al.; Trophozoites of Entamoeba histolytica, the protozoan parasite that causes amebic dysentery, phagocytose bacteria in the colonic lumen and erythrocytes (RBC) in host tissues . Because tissue invasion is an evolutionary dead end, it is likely that amebic pathogenicity is coincidentally selected, i.e., the same methods used to kill bacteria in the colonic lumen are used by parasites to damage host cells and cause disease . In support of this idea, the amebic lectin and pore-forming peptide are involved in binding and killing, respectively, bacteria and host epithelial cells . Here amebic phagocytosis of bacteria, RBC, and mucin-coated beads was disrupted by overexpression of E . histolytica p21(racA-V12), a ras-family protein involved in selection of sites of actin polymerization, which had been mutated to eliminate its GTPase activity . p21(racA-V12) transformants were also defective in capping and cytokinesis, while pinocytosis of fluorescent dextrans was not affected . Wortmannin, a fungal inhibitor of phosphoinositide 3-kinase, markedly inhibited phagocytosis of bacteria, RBC, and mucin-coated beads by wild-type amebae . In contrast to p21(racA-V12) overexpression, wortmannin abolished amebic pinocytosis of dextrans but had no inhibitory effects on capping . Inhibition of amebic vacuolar acidification by bafilomycin also decreased bacterial and RBC uptake . These results, which demonstrate similarities between mechanisms of phagocytosis of bacteria and RBC by amebae and macrophages, support the idea of coincidental selection of amebic genes encoding proteins that mediate destruction of host cells. Arch Biochem Biophys, 1997 Sep 15, 345(2), 223 - 9 Direct evidence for a soluble methane monooxygenase from type I methanotrophic bacteria: purification and properties of a soluble methane monooxygenase from Methylomonas sp . GYJ3; Shen R et al.; The hydroxylase and reductase components of a soluble methane monooxygenase from type I methanotrophs--Methylomonas sp . GYJ3--were purified by a multiple-step LC procedure . The hydroxylase (approximately 240 kDa, determined by an HPLC-size exclusion chromatography method) has three subunits with molecular masses of 56, 43, and 27 kDa, suggesting that the enzyme has an (alphabeta gamma)2 subunit structure . The HPLC method was developed to purify the hydroxylase component, and the purified protein has a specific activity of 541 nmol propene oxide x mg(-1) protein x min(-1), which is two times the specific activity of the protein purified by the two-step LC procedure . The iron content in the hydroxylase purified by the two-step LC procedure is 2.1 mol of Fe per mole of protein, but the iron content in the protein by the HPLC procedure is 3.78 mol of Fe per mole of protein . The diversity of iron contents in this protein is due mainly to the use of different purification methods . The reductase has a molecular mass of 42 kDa . The UV-VIS spectrum of the protein is similar to that of proteins from other methanotrophs, suggesting that the protein contains a FAD cofactor and a {2Fe-2S} center . The partially purified component B stimulated the MMO activity of the hydroxylase and reductase system by 40-fold. Gene, 1997 Aug 22, 195(2), 257 - 66 Three insertion sequences from the cyanobacterium Synechocystis PCC6803 support the occurrence of horizontal DNA transfer among bacteria; Cassier-Chauvat C et al.; Three insertion sequences were characterized from the widely-used cyanobacterium Synechocystis PCC6803 . They all harbored a putative transposase sequence flanked by two imperfect inverted repeats, seemed to have duplicated their target insertion site and occurred as multiple copies in the host genome . They exhibited no obvious homology with any other cyanobacterial ISs and were termed IS5S (871 bp), IS4S (1299 bp) and ISS1987 (949 bp) because they were, respectively, homologous to IS5- and IS4-bacterial elements, and to several members of the IS630-Tc1-mariner superfamily of IS elements occurring in a wide range of hosts . This suggests that these IS-elements were spread through horizontal transfer between evolutionary distant organisms . Three IS5S-copies were isolated as a rescue insertion into a replicating plasmid (IS5Sa), or subsequently cloned from a Synechocystis DNA-library probed with IS5Sa (IS5Sb and IS5Sc), and appeared to be almost identical . In the vicinity of IS5Sb, we found the ISS1987 element inserted into the IS4S element . This indicates that the ISS1987 element has been, and could still be, mobile since its transposase sequence is not interrupted with stop codons or translational frameshifts, unlike that which is found in most members of the IS630-Tc1-mariner superfamily of transposable elements. Zhonghua Hu Li Za Zhi, 1997 Mar, 32(3), 132 - 4 {Analysis of influential factors of suspended bacteria in air in operating rooms}; Ma ZY et al.; In order to control the air borne bacterial contamination of operation in operating rooms, we designed to do air sampling with FA-1 suspending air bacterial particle sampling kits . Samples were from purified operating rooms and nonpurified operating rooms, aseptic operation and contaminated operation . Data were collected in 7 different stages and 3 different altitudes . Data were statistically analysed by means of logistic linear model . The results help us understand the influencing factors of air contamination . Strategies of control of those factors were discussed. Biosci Biotechnol Biochem, 1997 Aug, 61(8), 1244 - 51 The phylogeny of acetic acid bacteria based on the partial sequences of 16S ribosomal RNA: the elevation of the subgenus Gluconoacetobacter to the generic level; Yamada Y et al.; Thirty-six strains of acetic acid bacteria classified in the genera Acetobacter, Gluconobacter, and Acidomonas were examined for their partial base sequences in positions 1220 through 1375, 156 bases, of 16S rRNA . The strains of the Q10-equipped Gluconobacter species examined were divided into two subgroups, which included the type strains of Gluconobacter oxydans, the type species of the genus Gluconobacter, and of a second species, Gluconobacter cerinus, respectively . The base differences numbered four between the two type strains . The strains of the Q9-equipped species examined classified in the type subgenus Acetobacter of the genus Acetobacter were not very distant phylogenetically from those of the genus Gluconobacter . The calculated number of base differences was 9-6 between the type strains of G . oxydans and G . cerinus and the type strains of Acetobacter aceti and Acetobacter pasteurianus . In contrast, the strains of the Q10-equipped species examined classified in the subgenus Gluconoacetobacter of the genus Acetobacter were very distant phylogenetically from those of the Acetobacter and Gluconobacter species mentioned above . The number of base differences was calculated to be 14-8 . Furthermore, the strains of the methanol-assimilating, Q10-equipped species of the genus Acidomonas examined were located in phylogenetically isolated positions . The type strain of Acidomonas methanolica (identical to Acetobacter methanolicus), the type species of the genus Acidomonas, had 16-9 base differences . The data obtained here indicated that the members of the subgenus Gluconoacetobacter of the genus Acetobacter can be distinguished at the generic level . The new genus Gluconoacetobacter was proposed with the type species, Gluconoacetobacter liquefaciens, in recognition of the genus Acidomonas along with the genera Acetobacter and Gluconobacter in the classification of the acetic acid bacteria. Biotechniques, 1997 Sep, 23(3), 494 - 8 One primer pair amplifies small subunit ribosomal DNA from mitochondria, plastids and bacteria . Mitochondria, plastids and bacteria; Berschick P; A pair of PCR primers, directed towards conserved regions of small ribosomal subunit RNA (SSU rRNA) genes, was used to amplify segments of animal and plant mtDNA, chloroplast DNA and bacterial DNA by PCR . PCR products of animal, plant and bacterial DNA differ in length, enabling separation for an "individual" sequence analysis . Using this technique, it was found that preparations of the body wall muscle and of mitochondria from the lugworm Arenicola marina used for physiological studies contain significant amounts of bacterial DNA . Since the use of these primers seems not to be taxonomically restricted, it offers new opportunities for phylogenetic and population research. J Am Dent Assoc, 1997 Sep, 128(9), 1263 - 71 Can one acquire periodontal bacteria and periodontitis from a family member? Asikainen S, Chen C, Alaluusua S, Slots J. Recent findings suggest that two major periodontal pathogenes, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, are transmitted among family members . The authors discuss the evidence of person-to-person transmission of periodontal bacteria, the significance of saliva as a vehicle of transmission and the methods of verifying clonal similarity of bacterial strains obtained from family members . The authors also discuss the prophylactic and therapeutic implications of the person-to-person spread of periodontal bacteria. Arch Microbiol, 1997 Oct, 168(4), 249 - 61 Behavioural responses of bacteria to light and oxygen; Armitage JP; Motile bacteria have long been known to swim towards or away from specific environmental stimuli such as nutrients, oxygen or light . Although there has been a detailed description of chemosensory responses in enteric species for several years, there has been little information on the mechanisms involved in responses to stimuli affecting electron transport as these usually also change the electrochemical proton gradient - at least transiently - and, thus, directly change flagellar rotation . There have, however, been major advances recently . Halobacterium salinarium uses a retinal-based sensory system to sense changes in specific wavelengths of light and to signal via a transmembrane sensory protein, which turns out to be homologous to the transmembrane chemoreceptors of Escherichia coli . A FAD-binding protein, also related to these receptors, signals changes in respiratory electron transport in E . coli . Rhodobacter sphaeroides cells do not respond to light or oxygen specifically, but sense a change in the rate of electron transfer, probably again using an electron-transport-chain-linked redox sensor, signalling through a common sensory pathway . These recent studies reveal that bacteria not only sense a range of environmental stimuli but also integrate the signals through common pathways to produce a balanced flagellar response. Antonie Van Leeuwenhoek, 1997 Jul, 72(1), 29 - 38 Verrucomicrobia div . nov., a new division of the bacteria containing three new species of Prosthecobacter; Hedlund BP et al.; Four strains of nonmotile, prosthecate bacteria were isolated in the 1970s and assigned to the genus Prosthecobacter . These strains were compared genotypically by DNA/DNA reassociation and 16S rDNA based phylogenetic analyses . Genotypic comparisons were complemented with phenotypic characterizations . Together, these studies clearly indicate each Prosthecobacter strain represents a novel species of bacteria . We propose three new species of Prosthecobacter, P . dejongeii strain FC1, P . vanneervenii strain FC2, and P . debontii strain FC3; P . fusiformis is reserved for the type strain of the genus, strain FC4 . Additionally, we propose the genera Prosthecobacter and Verrucomicrobium, currently members of the order Verrucomicrobiales, to comprise a novel higher order taxonomic group, the division Verrucomicrobia div . nov . and the class Verrumicrobiae class nov . Many novel members of the Verrucomicrobia, as revealed by molecular ecology studies, await isolation and description. Microbiol Mol Biol Rev, 1997 Sep, 61(3), 337 - 76 Biogenesis of respiratory cytochromes in bacteria; Thony-Meyer L; Biogenesis of respiratory cytochromes is defined as consisting of the posttranslational processes that are necessary to assemble apoprotein, heme, and sometimes additional cofactors into mature enzyme complexes with electron transfer functions . Different biochemical reactions take place during maturation: (i) targeting of the apoprotein to or through the cytoplasmic membrane to its subcellular destination; (ii) proteolytic processing of precursor forms; (iii) assembly of subunits in the membrane and oligomerization; (iv) translocation and/or modification of heme and covalent or noncovalent binding to the protein moiety; (v) transport, processing, and incorporation of other cofactors; and (vi) folding and stabilization of the protein . These steps are discussed for the maturation of different oxidoreductase complexes, and they are arranged in a linear pathway to best account for experimental findings from studies concerning cytochrome biogenesis . The example of the best-studied case, i.e., maturation of cytochrome c, appears to consist of a pathway that requires at least nine specific genes and more general cellular functions such as protein secretion or the control of the redox state in the periplasm . Covalent attachment of heme appears to be enzyme catalyzed and takes place in the periplasm after translocation of the precursor through the membrane . The genetic characterization and the putative biochemical functions of cytochrome c-specific maturation proteins suggest that they may be organized in a membrane-bound maturase complex . Formation of the multisubunit cytochrome bc, complex and several terminal oxidases of the bo3, bd, aa3, and cbb3 types is discussed in detail, and models for linear maturation pathways are proposed wherever possible. Appl Environ Microbiol, 1997 Sep, 63(9), 3359 - 66 Dominant marine bacterioplankton species found among colony-forming bacteria; Pinhassi J et al.; The density of specific aquatic bacteria was determined by use of whole-genome DNA hybridization towards community DNA . From a coastal marine environment (northern Baltic Sea), 48 specific bacteria were isolated on solid media over a 1-year period . Based on the presented hybridization protocol, the total density of the isolates ranged between 7 and 69% of the bacteria determined by acridine orange direct counts . When compared to the number of nucleoid-containing cells, the range increased to 29 to 111% . Thus, our results showed that bacteria able to form colonies on solid media accounted for a large fraction of the bacterioplankton . There were significant changes in the density of the different bacteria over the year, suggesting that bacterioplankton exhibit a seasonal succession analogous to phytoplankton . The bacteria studied were of diverse phylogenetic origin, being distributed among the alpha, beta, and gamma subdivisions of the class Proteobacteria and the cytophaga-flexibacter group . Partial 16S rRNA gene sequence analysis of 29 Baltic Sea isolates as well as of 30 Southern California Bight isolates showed that a majority of the isolates had low similarity (0.85 to 0.95) to reported sequence data . This indicated that the diversity of marine bacteria able to grow on solid media is largely unexplored. Mol Mar Biol Biotechnol, 1997 Sep, 6(3), 260 - 7 Ribosomal RNA gene dosage in marine bacteria; Kerkhof L et al.; Ribosomal RNA gene dosage was determined for 20 marine heterotrophic bacteria using short probes (< 600 bp) from the Escherichia coli 16S rRNA gene and Southern blot analysis . All Bacterial strains had between 4 and 10 copies of the 16S rRNA genes in their genomes . This report presents important preliminary data for developing quantitative molecular methods to address population dynamics of marine based of 16S rRNA sequences. Mol Mar Biol Biotechnol, 1997 Sep, 6(3), 238 - 47 Alteration in plasmid DNA following natural transformation to populations of marine bacteria; Williams HG et al.; This article examines alterations in a broad-host-range plasmid (pQSR50) that were observed following transfer to indigenous marine bacteria by natural transformation . Plasmid DNA from the transformants had altered restriction profiles . However, with the exception of the EcoRI site from one transformant (BS10), fragments amplified by polymerase chain reaction (PCR) and encompassing the recognition sites were cleaved by the relevant endonucleases, providing the sites were present . Analysis with DpnI and MboI indicated differences in DNA methylation between pQSR50 and the transformants . The missing EcoRI site from BS10 and smaller EcoRI fragments observed in transformants indicated that rearrangements had also occurred . Evolution of novel plasmid molecules following gene transfer may be an important mechanism by which natural genetic diversity is generated. Biophys J, 1997 Aug, 73(2), 994 - 1000 Magneto-aerotaxis in marine coccoid bacteria; Frankel RB et al.; Magnetotactic cocci swim persistently along local magnetic field lines in a preferred direction that corresponds to downward migration along geomagnetic field lines . Recently, high cell concentrations of magnetotactic cocci have been found in the water columns of chemically stratified, marine and brackish habitats, and not always in the sediments, as would be expected for persistent, downward-migrating bacteria . Here we report that cells of a pure culture of a marine magnetotactic coccus, designated strain MC-1, formed microaerophilic bands in capillary tubes and used aerotaxis to migrate to a preferred oxygen concentration in an oxygen gradient . Cells were able to swim in either direction along the local magnetic field and used magnetotaxis in conjunction with aerotaxis, i.e., magnetically assisted aerotaxis, or magneto-aerotaxis, to more efficiently migrate to and maintain position at their preferred oxygen concentration . Cells of strain MC-1 had a novel, aerotactic sensory mechanism that appeared to function as a two-way switch, rather than the temporal sensory mechanism used by other bacteria, including Magnetospirillum megnetotacticum, in aerotaxis . The cells also exhibited a response to short-wavelength light (< or = 500 nm), which caused them to swim persistently parallel to the magnetic field during illumination. J Mol Evol, 1997 Aug, 45(2), 131 - 6 Horizontal transfer of genes coding for the photosynthetic reaction centers of purple bacteria; Nagashima KV et al.; Phylogenetic trees were drawn and analyzed based on the nucleotide sequences of the 1.5-kb gene fragment coding for the L and M subunits of the photochemical reaction center of various purple photosynthetic bacteria . These trees are mostly consistent with phylogenetic trees based on 16S rRNA and soluble cytochrome c, but differ in some significant details . This inconsistency implies horizontal transfer of the genes that code for the photosynthetic apparatus in purple bacteria . Possibilities of similar transfers of photosynthesis genes during the evolution of photosynthesis are discussed especially for the establishment of oxygenic photosynthesis. J Virol, 1997 Aug, 71(8), 5774 - 81 Human immunodeficiency virus type 1 (HIV-1) protein Vif inhibits the activity of HIV-1 protease in bacteria and in vitro; Kotler M et al.; Human immunodeficiency virus type 1 (HIV-1) Vif is required for productive infection of T lymphocytes and macrophages . Virions produced in the absence of Vif have abnormal core morphology and those produced in primary T cells carry immature core proteins and low levels of mature capsid (M . Simm, M . Shahabuddin, W . Chao, J . S . Allan, and D . J . Volsky, J . Virol . 69:4582-4586, 1995) . To investigate whether Vif influences the activity of HIV-1 protease (PR), the viral enzyme which is responsible for processing Gag and Gag-Pol precursor polyproteins into mature virion components, we transformed bacteria to inducibly express truncated Gag-Pol fusion proteins and Vif . We examined the cleavage of polyproteins consisting of matrix to PR (Gag-PR), capsid to PR (CA-PR), and p6Pol to PR (p6Pol-PR) and evaluated HIV-1 protein processing at specific sites by Western blotting using antibodies against matrix, capsid, and PR proteins . We found that Vif modulates HIV-1 PR activity in bacteria mainly by preventing the release of mature MA and CA from Gag-PR, CA from CA-PR, and p6Pol from p6Pol-PR, with other cleavages being less affected . Using subconstructs of Vif, we mapped this activity to the N-terminal half of the molecule, thus identifying a new functional domain of Vif . Kinetic study of p6Pol-PR autocatalysis in the presence or absence of Vif revealed that Vif and N'Vif reduce the rate of PR-mediated proteolysis of this substrate . In an assay of in vitro proteolysis of a synthetic peptide substrate by purified recombinant PR we found that recombinant Vif and the N-terminal half of the molecule specifically inhibit PR activity at a molar ratio of the N-terminal half of Vif to PR of about 1 . These results suggest a mechanism and site of action of Vif in HIV-1 replication and demonstrate novel regulation of a lentivirus PR by an autologous viral protein acting in trans. FEMS Microbiol Lett, 1997 Jul 15, 152(2), 355 - 61 Oral bacteria inhibit Helicobacter pylori growth; Ishihara K et al.; Various oral bacterial species were found to inhibit the growth of Helicobacter pylori strains . The growth inhibitory activities of most of these oral bacteria were adversely affected by heating at 80 degrees C for 60 min or by protease treatment, indicating that these bacteria produce bacteriocin-like inhibitory proteins against H . pylori strains . The antagonistic effects of oral bacteria against H . pylori may restrain colonization by this organism in the oral cavity. J Biochem (Tokyo), 1997 Jul, 122(1), 41 - 8 Structure and expression of the dnaKJ operon of Buchnera, an intracellular symbiotic bacteria of aphid; Sato S et al.; Buchnera sp., an intracellular symbiont of the pea aphid (Acyrthosiphon pisum Harris), is a close phylogenetical relative of Escherichia coli, and synthesizes a large amount of symbionin, a GroEL homolog . The other heat shock protein homologs, which are not expressed as much as symbionin, have not been studied yet . In this study, we cloned the dnaK and dnaJ genes of Buchnera, and revealed that its DnaK and DnaJ are structurally very similar to those of E . coli . Amino acid residues and motifs proposed so far to be essential for the function of the E . coli DnaK and DnaJ were completely conserved in the Buchnera counterparts . However, Buchnera dnaKJ operon could not fully complement mutations of either dnaK or dnaJ of E . coli . This is probably because of a difference in net charge of DnaK and DnaJ between Buchnera and E . coli, and a unique structure of Buchnera DnaJ that prevents heterologous components from operating in concert . Buchnera dnaK and dnaJ formed an operon whose transcription is governed by a promoter structurally homologous to heat shock promoters of E . coli, although the cellular amount of dnaKJ mRNA was not affected by heat shock . Two inverted repeats flanking both sides of E . coli dnaJ were also found in the gene of Buchnera at the corresponding positions, suggesting that expression ratio of DnaK to DnaJ is regulated in a similar manner in the two organisms. J Med Microbiol, 1997 Jul, 46(7), 571 - 8 Selective translocation of coliform bacteria adhering to caecal epithelium of rats during catabolic stress; Katouli M et al.; Adult conventional rats were starved for 48 h with or without haemorrhage at 24 h, and translocation of caecal coliforms to mesenteric lymph nodes (MLNs) was measured . Translocation was detected in three of 11 rats without haemorrhage, in 6 of 11 starved and sham-operated rats and in 12 of 22 rats after haemorrhage . In contrast, only one of 13 non-instrumented and fed control rats showed translocation . Translocation was associated with more coliforms adhering to caecal epithelium in rats . Coliform isolates from caecum, caecal epithelium and MLNs were characterised and grouped into different biochemical phenotypes (BPTs) by a biochemical fingerprinting method . Of 291 BPTs detected in the caecum of all rats, 108 were also found on caecal epithelium; 36 BPTs were detected in MLNs, of which 17 were not detected either in the caecum or on the caecal epithelium of the corresponding rats . One isolate from each of these 36 BPTs was selected and compared to the others . Four common (C) BPTs (i.e., C1-C4) were identified among them . Strains of C1 formed the majority of isolates from the caecum (79%), caecal epithelium (71%) and MLNs (91%) . In contrast, C2-C4 had a significantly lower incidence both in the caecum and on the caecal epithelium, but not in the MLNs . These findings indicate that not all caecal coliforms adhere to the epithelium during catabolic stress and that for translocation to occur, other bacterial properties besides adhesion are needed . It is also concluded that coliforms with a low incidence in the caecum can translocate with the same efficiency as those with a high incidence. Curr Microbiol, 1997 Jul, 35(1), 44 - 7 Competition between ruminal cellulolytic bacteria for adhesion to cellulose; Mosoni P et al.; Competition for adhesion to cellulose among the three main ruminal cellulolytic bacterial species was studied using differential radiolabeling (14C/3H) of cells . When added simultaneously to cellulose, Ruminococcus flavefaciens FD1 and Fibrobacter succinogenes S85 showed some competition; however, both species were surpassed competitively by Ruminococcus albus 20 . When R . flavefaciens FD1 and F . succinogenes S85 were already adherent, R . albus 20 adhesion occurred without inhibition but involved R . flavefaciens FD1 detachment. Microbiologia, 1997 Jun, 13(2), 209 - 14 Growth of methylaminotrophic, acetotrophic and hydrogenotrophic methanogenic bacteria on artificial supports; Urrutia H et al.; The efficiency of organic matter degradation in attached biomass reactors depends on the suitable selection of artificial support for the retention of bacterial communities . We have studied the growth on glass and clay beads of methylaminotrophic, acetotrophic and hydrogenotrophic methanogenic bacterial communities isolated from anaerobic reactors . Bacterial counts were performed by the standard MPN technique . Experiments were performed in 50 ml vials for 12 days at 35 degrees C . Increase in the counts of methylaminotrophic and hydrogenotrophic methanogens occurred on both glass and clay beads . The latter support material also stimulated the growth rate of methylaminotrophic methanogens. J Anim Sci, 1997 Jun, 75(6), 1621 - 32 Regulation of uterine immune function during the estrous cycle and in response to infectious bacteria in sheep; Ramadan AA et al.; Uterine infections are a major reproductive problem in livestock . We conducted two experiments to investigate factors that may modulate uterine responses to infectious bacteria . In Exp . 1, ewes received intrauterine inoculations of either saline or bacteria (75 x 10(7) cfu of Actinomyces pyogenes and 35 x 10(7) cfu of Escherichia coli) on either d 0 or 7 of the estrous cycle . Vena caval samples containing uteroovarian blood were collected twice daily from 12 h before until 6 d after inoculation . Only ewes inoculated with bacteria on d 7 developed infections . Basal (4.8 vs .4 pmol), lipopolysaccharide-stimulated (14.2 vs 6.1 pmol), and concanavalin A-stimulated (65.8 vs 21.6 pmol) blastogenesis (i.e., {3H}thymidine incorporation) of vena caval lymphocytes was greater (P < or = .002) for ewes inoculated with bacteria or saline on d 0 rather than on d 7 . The number (per 100 white blood cells) of lymphocytes was greater (41.3 vs 30.8, P < .001) and that of neutrophils was less (42.5 vs 51.6, P < .001) in ewes inoculated on d 0 rather than d 7 . Bacteria increased (P < .05) vena caval PGF(2 alpha) but not PGE2 concentrations . In Exp . 2, two protein fractions (molecular weights of > or = 100 kDa and approximately 12.7 kDa) from chromatography of uterine flushings collected on d 0 or 7, or 18 d after ovariectomy on d 0 or 7, modulated phytohemagglutinin-stimulated blastogenesis; the heavier fraction from d 0 had a stimulatory component, but the major effects of the fractions were inhibitory . The differences in immune function and regulation between d 0 and 7 probably explain how the uterus of follicular phase ewes was able to prevent the development of an infection. J Trauma, 1997 Jun, 42(6), 1073 - 9 Influence of selective decontamination of the digestive tract on cell-mediated immune function and bacteria/endotoxin translocation in thermally injured rats; Yao YM et al.; OBJECTIVE: To determine the influence of pretreatment with selective decontamination of the digestive tract (SDD) on systemic immunosuppression, and the relationship between bacteria/endotoxin translocation and abnormalities of immune function in thermally injured rats . DESIGN, MATERIALS, AND METHODS: Animals were subjected to a 40% full-thickness scald injury, and divided into SDD-treated and control groups . The treatment group received SDD (polymyxin E, tobramycin, and 5-flucytosine) by gavage twice daily for 3 days before the experiment and continued for 5 days after thermal injury . The control group was given the same amount of water . The parameters reflecting cell-mediated immunity, including splenocyte proliferation in response to mitogens, interleukin 2 (IL-2) production, and lymphocyte subpopulation, were measured before injury and 1 and 5 days after burn, respectively . MEASUREMENTS AND MAIN RESULTS: Thermal injury resulted in marked reduction in splenocyte proliferative response to T-cell mitogens, IL-2 production, and T-helper/suppressor cells (CD4/CD8) ratio . Prophylactic treatment with SDD significantly decreased the incidences of bacterial translocation and endotoxemia, prevented suppressive mitogenic response and inadequate IL-2 production (p < 0.05-0.01) but did not affect the abnormal ratio of CD4 to CD8 T lymphocytes in blood (p > 0.05) . CONCLUSIONS: These results suggest that bacteria/endotoxin translocation from the gut appears to be involved in cell-mediated immune dysfunction as a consequence of thermal injury . Pretreatment with SDD might attenuate postburn immunosuppression by preventing translocation events. Curr Opin Struct Biol, 1997 Jun, 7(3), 407 - 15 Modular multidomain phosphoryl transfer proteins of bacteria; Reizer J et al.; Recent phylogenetic and structural analyses of multidomain phosphoryl transfer proteins of bacteria have revealed that interdomain (but not intradomain) splicing and fusion, as well as domain duplication and deletion, have occurred frequently during evolution . These events have been found to be exceedingly rare in certain other protein families . Domain-shuffling events are illustrated by examples from the superfamilies of phosphoenolpyruvate-dependent sugar phosphotransferase systems, their transcriptional regulatory protein targets of phosphorylation, sensor autokinase/response regulator signal transduction systems, and permeases of the ATP-binding-cassette type. Surg Clin North Am, 1997 Jun, 77(3), 637 - 50 Wound infection . A failure of wound healing caused by an imbalance of bacteria; Robson MC; Infection in a wound, like infection elsewhere in the body, is a manifestation of a disturbed host-bacteria equilibrium in favor of the bacteria . This not only elicits a systemic septic response but actually inhibits the multiple processes involved in the wound healing scheme . Each process involved in healing is affected when bacteria proliferate in a wound . Wound infection, whether in an intentional operative incision, an acute traumatic laceration, or a chronic pressure ulcer, results when bacteria indigenous to the patient or exogenous to the wound achieve dominance over the systemic and local factors of host resistance . To be able to prevent and manage wound infections requires an understanding of how each prophylactic or therapeutic maneuver works to maintain or re-establish the bacteria-host balance . Only when this equilibrium is in balance can the normal processes of wound healing proceed to give a satisfactory healing trajectory. Gastroenterology, 1997 Jun, 112(6), 1971 - 8 Effects of intestinal stasis on intercellular adhesion molecule 1 expression in the rat: role of enteric bacteria; Komatsu S et al.; BACKGROUND & AIMS: The mechanisms underlying the inflammatory changes associated with intestinal stasis are poorly understood . The objective of this study was to assess whether endothelial expression of intercellular adhesion molecule 1 (ICAM-1) and leukocyte recruitment are altered after intestinal stasis . METHODS: ICAM-1 expression and granulocyte recruitment were quantified in different tissues of Sprague-Dawley rats using the double-radiolabeled monoclonal antibody technique and peroxidase activity, respectively . RESULTS: Both constitutive and endotoxin-induced ICAM-1 expression were significantly higher in the cecum than in distal colon, a finding that cannot be explained by a difference in endothelial surface area between the two organs . Surgical procedures to improve cecal stool flow (cecostomy, ileocecostomy) elicited a significant decrease in constitutive ICAM-1 expression in both cecum and distal colon . Tissue peroxidase activity was normally higher in cecum than in distal colon, and this difference was significantly reduced by ileocecostomy . Oral administration of antibiotics (kanamycin and/or metronidazole for 2 days) significantly reduced constitutive ICAM-1 expression in the cecum, but not in the distal colon . CONCLUSIONS: This study indicates that intestinal stasis is associated with an increased expression of ICAM-1 and granulocyte infiltration, which may be mediated by enteric bacteria. Curr Microbiol, 1997 Jun, 34(6), 340 - 7 The osmotic-1 locus of Neurospora crassa encodes a putative histidine kinase similar to osmosensors of bacteria and yeast; Schumacher MM et al.; Osmotically sensitive mutants of Neurospora crassa are unable to grow on medium supplemented with 4% NaCl, have altered morphologies and cell-wall compositions, and are resistant to dicarboximide fungicides . Osmotic-1 (os-1) mutants have a unique characteristic of forming protoplasts that grow and divide in specialized liquid medium, suggesting that the os-1+ gene product is important for cell-wall assembly . A cosmid containing the os-1+ locus of N . crassa, isolated from a genomic cosmid library by chromosomal walk from a closely linked gene, was used to subclone the os-1+ gene by functional complementation of an os-1 mutant . Analysis of the sequence of complementing DNA predicts that os-1+ encodes a predicted protein similar to sensor-histidine kinases of bacteria and a yeast osmosensor-histidine kinase . Importantly, the predicted os-1+ protein is identical to the N . crassa nik-1 predicted protein that was identified by using polymerase chain reaction primers directed against histidine kinase consensus DNA sequences . Our results indicate that nik-1 and os-1 encode the same osmosensing histidine kinase that plays an important role in the regulation of cell-wall assembly and, probably, other cell responses to changes in external osmolarity. Antonie Van Leeuwenhoek, 1997 May, 71(4), 363 - 8 Molecular evolution in bacteria: surfaces, cathodes and anodes; Trevors JT; Molecular evolution is examined in bacteria with an emphasis on mineral surfaces, membranes, cathodes and anodes . In early molecular evolution, cathode-anode system may have been naturally occurring on a nm to micron scale . Secondly, the cathode-anode system could have been separated by a primitive, permeable lipid or microsphere on a mineral surface, that was a precursor of a more advanced membrane with a charge differential on either side of the membrane . These aspects will be considered from a theoretical evolutionary perspective. Electrophoresis, 1997 May, 18(5), 834 - 9 Analysis of proteins from different phase variants of the entomopathogenic bacteria Photorhabdus luminescens by two-dimensional zymography; Ong KL et al.; Two-dimensional zymography which combines two-dimensional electrophoresis with zymography was used to analyze proteases and other proteins produced by different phase variants of two strains of Photorhabdus luminescens . Both the primary and secondary phases of P . luminescens strains Hp and Hm secreted proteases . The protease in P . luminescens Hp has a molecular weight (Mr) of 57,000 and an isoelectric point (pI) of 4.4 whereas that in P . luminescens Hm has an Mr of 59,000 and pI of 4.9 . Several putative protease degradation products were clearly visible in the zymograms from both bacterial strains . Two-dimensional zymography also showed that several secretory proteins were present only in particular phase variants and therefore could be used as specific markers . Unexpectedly, the two-dimensional zymography revealed that a nonsecretory protease with an Mr of 47,000 and a pI of 4.0 was present in the cell extracts of all phases of both P . luminescens Hp and Hm . The application of the two-dimensional zymography for the identification of other enzymes was also discussed. Trends Microbiol, 1997 May, 5(5), 184 - 8 Intercellular communication and group behavior in bacteria; Gray KM; Group behavior in bacterial populations requires intercellular communication, generally by means of self-produced signals . As the model system of bacterial quorum sensing demonstrates, the integration of these 'group' signals with other global regulators can lead to very complex and sophisticated interactions that are not necessarily limited to the signal-producing species alone. Appl Environ Microbiol, 1997 May, 63(5), 1847 - 51 Glucose transport by mixed ruminal bacteria from a cow; Kajikawa H et al.; The glucose transport of mixed ruminal bacteria harvested from a holstein cow fed 5.0 kg of Italian ryegrass and 1.5 kg of flaked corn a day was investigated . The Eadie-Hofstee plot characterized two transport systems: a high-affinity, low-velocity system and a low-affinity, high-velocity system . The former system (K(m) = 16 microM; Vmax = 2.2 nmol/min/mg of protein) is considered dominant under this feeding condition based on the glucose concentration in the rumen (< 1 mM) . In light of the facts that the protonophore SF6847 and the lipophilic triphenylmethyl phosphonium ion had no effect on the high-affinity system and an artificially generated proton gradient and electrical potential across the cell membrane did not increase glucose transport, a proton motive force is not be involved in the system . On the other hand, from the facts that chlorhexidine inhibited about 90% of the high-affinity system while iodoacetate showed no significant effect, and a high phosphoenolpyruvate-dependent phosphorylation of glucose was actually shown, the phosphoenolpyruvate-dependent phosphotransferase system is considered the main system in the high-affinity system . Moreover, as shown by the facts that harmaline inhibited about 30% of the high-affinity system and the artificially generated sodium gradient across the cell membrane significantly stimulated glucose transport, this system also includes sodium symport to some degree . The high-affinity system was sensitive to a decrease in pH (< 6.5) and was inhibited by the presence of sucrose, mannose, and fructose. Appl Environ Microbiol, 1997 May, 63(5), 1721 - 4 Subcuticular bacteria from the brittle star Ophiactis balli (Echinodermata: Ophiuroidea) represent a new lineage of extracellular marine symbionts in the alpha subdivision of the class Proteobacteria; Burnett WJ et al.; Many species of echinoderms, in all five extant classes, contain subcuticular bacterial symbionts (SCB) . The role of these extracellular symbionts and the nature of the relationship remain unclear . We have sequenced 16S rRNA genes from symbionts to determine their phylogenetic affinities . Symbionts of an ophiuroid, Ophiactis balli, appear closely related to bacteria within the alpha group of the class Proteobacteria, including intracellular endosymbionts and pathogens . SCB are clearly of separate origin from other documented major groups of marine symbiotic bacteria. J Biomed Mater Res, 1997 May, 35(2), 217 - 32 Tissue reactions to bacteria-inoculated rat lead samples . I . Effect of local gentamicin release through vicinal sponge or solution-dipping; van Wachem PB et al.; The effect of local gentamicin release through a vicinal collagen sponge or through preoperative solution-dipping of rat lead samples was investigated in an early-infection model . The efficacy of these methods and their effect on tissue response were determined . It was demonstrated that both methods of local gentamicin release suppress lead-related infectious complications as compared to the control lead, which showed a high presence of inflamed/infected tissues and bacterial growth at each explantation time point . The first day the vicinal collagen sponge was more effective in suppressing the infection than was the solution-dipped lead, probably because there is a faster and higher dose release of gentamicin from the sponge . However, continued implantation time revealed that gentamicin release from the solution-dipped lead was more effective than the sponge . This supports our hypothesis that the presence of lumina are decisive for bacterial growth and persistence of implant-related infections. Biochem J, 1997 Apr 15, 323 ( Pt 2), 393 - 9 Structure of a truncated human surfactant protein D is less effective in agglutinating bacteria than the native structure and fails to inhibit haemagglutination by influenza A virus; Eda S et al.; Surfactant protein D (SP-D) is a lung-specific protein that is synthesized and secreted by lung epithelial cells and is believed to play an important role in lung host defence . This protein belongs to the C-type lectin family, which is characterized by an N-terminal cysteine-rich domain, a collagen-like domain, a neck domain and a carbohydrate recognition domain (CRD) . To elucidate the biological actions of this animal lectin against such pathogens as micro-organisms, the biological activities of a recombinant partial SP-D lacking a collagen-like domain were examined . A recombinant human SP-D, consisting of a short collagen region (two repeats of Gly-Xaa-Yaa amino acid sequences), the neck domain and the CRD, was expressed in Escherichia coli . The recombinant SP-D was purified on a nickel column and then on a maltose-agarose column . This protein can form a trimeric structure owing to the neck domain and exhibits sugar-binding activity and specificity similar to those of native human SP-D . The recombinant SP-D caused dose-dependent and calcium-dependent agglutination of E . coli Y1088 . The agglutination titre (the concentration required to achieve a 50% decrease in light transmission by agglutination) of recombinant SP-D was approx . 6-fold that of native SP-D . As for conglutination, the recombinant trimeric conglutinin required 8-16-fold higher concentrations than the native counterpart . In haemagglutination inhibition (HI) of influenza A virus, although native and recombinant conglutinin showed similar levels of HI activity, the recombinant SP-D was unable to inhibit haemagglutination, even at a concentration approx . 120-fold that of the native SP-D . The lectin precipitation and lectin blot assays showed that the truncated SP-D could bind to influenza A virus as well as native SP-D did . These results indicate that the agglutination activity of trimeric collectins can be largely retained, and furthermore that the oligomeric structure with several hands at opposite sites can enhance agglutination activity . The difference in HI activity against influenza A virus between native and recombinant SP-D suggests that SP-D uses a different mechanism from that of conglutinin to inhibit viral haemagglutination. Biochemistry, 1997 Apr 15, 36(15), 4489 - 96 pH-metric study of reaction centers from photosynthetic bacteria in micellular solutions: protonatable groups equilibrate with the aqueous bulk phase; Kalman L et al.; Hydrogen ion equilibria of the reaction center protein from photosynthetic purple bacteria Rhodobacter sphaeroides and Rhodobacter capsulatus dissolved in micellular solution were studied by acid-base titration to estimate the water accessibility of protonatable residues of the protein determined from structural data . The ionizable amino acids of the reaction center underwent protonation-deprotonation with protons from the interfacial layer, which, however, exchanged protons from the aqueous bulk phase . The equilibrium was described in terms of the buffering capacity of the multiphase system . The detergents decreased the proton activity coefficient (increased the buffering capacity) of the aqueous solution by a factor of 0.33 (in 0.03% Triton X-100 and LDAO) and 0.12 (0.04% dodecyl beta-D-maltoside) . The observed buffering capacities of the reaction center protein were large and detergent-dependent . However, corrections for proton activities made the pH dependence of buffering capacities in different detergents uniform and similar to that expected from the number and pK values of protonatable groups of the protein . The vast majority of protonatable amino acids of the reaction center are in protonation equilibria with the aqueous bulk phase on an extended time scale. Biochemistry (Mosc), 1997 Apr, 62(4), 386 - 90 A secretory protein involved in the antagonistic interactions between methanotrophic bacteria; Pashkova NI et al.; Antagonistic interactions in mixed culture of methanotrophic bacteria Methylomonas methanica 12 and Methylocystis minimus 33 were investigated . The inhibitory action of Mcs . minimus exometabolites against Mm . methanica grown in liquid medium was found to be specific . Ultrafiltration established that the molecular weight of the substance having inhibitory activity lies within the range 2-10 kD . The activity is protease sensitive and relatively stable to heating . Electrophoretic analysis showed that a protein with molecular weight of approximately 8 kD prevailed in Mcs . minimus culture liquid . When Mm . methanica cells were incubated in culture liquid of Mcs . minimus, the sorption of the 8 kD protein by target cells was observed . This suggests that the inhibitory effect may be associated with the 8 kD protein which has properties similar to known bacteriocins. Vet Med (Praha), 1997 Apr, 42(4), 111 - 23 {Use of molecular genetics for identification and differentiation of various strains and species of bacteria}; Rychlik I et al.; The aim of the paper is to inform on methods and practical application of DNA fingerprinting in typing of living organisms . Methods discussed in the review include standard DNA fingerprinting, plasmid profile analysis, RAPD PCR and direct sequencing of selected parts of genomes . In each method molecular basis together with its advantages and limitations is explained . All described methods are supplemented with selected cases of their practical application. J Appl Microbiol, 1997 Apr, 82(4), 455 - 61 Analysis of cytotoxicity and invasiveness of heterotrophic plate count bacteria (HPC) isolated from drinking water on blood media; Edberg SC et al.; Heterotrophic plate count (HPC) bacteria are naturally present in all aqueous environments . These bacteria undergo multiplication cycles in drinking water, especially in closed containers (bottled water) or in tap water when chlorine levels are dissipated, such as in dead ends in water mains or household plumbing . A study was undertaken to estimate health risk from these naturally occurring bacteria by the determination of cytotoxicity and invasiveness in a human enterocyte cell line . HPC bacteria were isolated from bottled and tap water samples by enumerating them under physical and chemical conditions analogous to human physiology . All HPC bacteria were examined at both log and lag phase of their growth cycles . Bacterial broth supernatant fluids were also tested to serve as critical negative controls . Naturally occurring HPC bacteria demonstrated low invasiveness and cytotoxicity with more than 95% of isolates showing equivalency to broth supernatant fluid . When showing either invasiveness or cytotoxicity, only a small number of cells from the culture were positive . Of those that were positive, log phase HPC bacteria were significantly more cytotoxic and invasive than those from stationary phase . Bacterial broth controls demonstrated varied, but often marked, cytotoxicity. Appl Environ Microbiol, 1997 Apr, 63(4), 1564 - 9 Influence of water chlorination on the counting of bacteria with DAPI (4',6-diamidino-2-phenylindole); Saby S et al.; Counting bacteria in drinking water samples by the epifluorescence technique after 4',6-diamidino-2-phenylindole (DAPI) staining is complicated by the fact that bacterial fluorescence varies with exposure of the cells to sodium hypochlorite . An Escherichia coli laboratory-grown suspension treated with sodium hypochlorite (5 to 15 mg of chlorine liter-1) for 90 min was highly fluorescent after DAPI staining probably due to cell membrane permeation and better and DAPI diffusion . At chlorine concentrations greater than 25 mg liter-1, DAPI-stained bacteria had only a low fluorescence . Stronger chlorine doses altered the DNA structure, preventing the DAPI from complexing with the DNA . When calf thymus DNA was exposed to sodium hypochlorite (from 15 to 50 mg of chlorine liter-1 for 90 min), the DNA lost the ability to complex with DAPI . Exposure to monochloramine did not have a similar effect . Treatment of drinking water with sodium hypochlorite (about 0.5 mg of chlorine liter-1) caused a significant increase in the percentage of poorly fluorescent bacteria, from 5% in unchlorinated waters (40 samples), to 35 to 39% in chlorinated waters (40 samples) . The presence of the poorly fluorescent bacteria could explain the underestimation of the real number of bacteria after DAPI staining . Microscopic counting of both poorly and highly fluorescent bacteria is essential under these conditions to obtain the total number of bacteria . A similar effect of chlorination on acridine orange-stained bacteria was observed in treated drinking waters . The presence of the poorly fluorescent bacteria after DAPI staining could be interpreted as a sign of dead cells. Proc Natl Acad Sci U S A, 1997 Apr 1, 94(7), 3274 - 8 Prevention of insect-borne disease: an approach using transgenic symbiotic bacteria; Durvasula RV et al.; Expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting insects may serve as a powerful approach to control certain arthropod-borne diseases . The endosymbiont of the Chagas disease vector, Rhodnius prolixus, has been transformed to express cecropin A, a peptide lethal to the parasite, Trypanosoma cruzi . In insects carrying the transformed bacteria, cecropin A expression results in elimination or reduction in number of T . cruzi . A method has been devised to spread the transgenic bacteria to populations of R . prolixus, in a manner that mimics their natural coprophagous route of symbiont acquisition. J Biol Chem, 1997 Mar 7, 272(10), 6805 - 11 Phosphorylation of protein kinase Cdelta (PKCdelta) at threonine 505 is not a prerequisite for enzymatic activity . Expression of rat PKCdelta and an alanine 505 mutant in bacteria in a functional form; Stempka L et al.; A structural feature shared by many protein kinases is the requirement for phosphorylation of threonine or tyrosine in the so-called activation loop for full enzyme activity . Previous studies by several groups have indicated that the isotypes alpha, betaI, and betaII of protein kinase C (PKC) are synthesized as inactive precursors and require phosphorylation by a putative "PKC kinase" for permissive activation . Expression of PKCalpha in bacteria resulted in a nonfunctional enzyme, apparently due to lack of this kinase . The phosphorylation sites for the PKC kinase in the activation loop of PKCalpha and PKCbetaII could be identified as Thr497 and Thr500, respectively . We report here that PKCdelta, contrary to PKCalpha, can be expressed in bacteria in a functional form . The activity of the recombinant enzyme regarding substrate phosphorylation, autophosphorylation, and dependence on activation by 12-O-tetradecanoylphorbol-13-acetate as well as the Km values for two substrates are comparable to those of recombinant PKCdelta expressed in baculovirus-infected insect cells . By site-directed mutagenesis we were able to show that Thr505, corresponding to Thr497 and Thr500 of PKCalpha and PKCbetaII, respectively, is not essential for obtaining a catalytically competent conformation of PKCdelta . The mutant Ala505 can be activated and does not differ from the wild type regarding activity and several other features . Ser504 can not take over the role of Thr505 and is not prerequisite for the kinase to become activated, as proven by the unaffected enzyme activity of respective mutants (Ala504 and Ala504/Ala505) . These results indicate that phosphorylation of Thr505 is not required for the formation of functional PKCdelta and that at least this PKC isoenzyme differs from the isotypes alpha, betaI, and betaII regarding the permissive activation by a PKC kinase. Lett Appl Microbiol, 1997 Mar, 24(3), 207 - 10 Use of oxygen-permeable silicone rubber pouches for growing mass cultures of bacteria; Giambernardi TA et al.; Growth of most bacteria often involves the use of expensive incubated shaker systems . In this report, oxygen-permeable silicone rubber pouches, with oxygen permeability over 100 times higher than other polymers, were employed for growing bacterial cultures . With little, if any, agitation oxygen-permeable silicone rubber pouches produced bacterial growth rates equivalent to growth rates obtained in shaker flasks . The silicone rubber pouch described has a glass cuvette integrated into its design that permits readings of bacterial density without opening the pouch . One can sterilize and store powdered bacterial culture medium in silicone rubber pouches; therefore, bacterial cultures can be initiated by simply adding water and bacteria. J Bacteriol, 1997 Mar, 179(6), 2047 - 52 Transposition without transposase: a spontaneous mutation in bacteria; Rappleye CA et al.; Transposition mutations are typically associated with the activities of transposable elements such as transposons and insertion sequences, whose mobility is dependent upon transposase enzymes that catalyze exchanges between element ends and target sites . We describe a single transposition event in which a block of donor sequence is inserted at a target site without the involvement of any known transposase or the ends of any known transposable element . We propose that this is a new type of spontaneous mutation which may be difficult to detect in standard mutant hunts but may be of evolutionary importance. Tidsskr Nor Laegeforen, 1997 Feb 28, 117(6), 838 - 41 {Floor cleaning methods of patients' room . Effect on bacteria, dirt and particles}; Andersen BM et al.; The effect of floor cleaning on bacteria, organic materials and particles in the patients' rooms was studied at Ulleval University Hospital, Oslo, Norway . Four cleaning methods were compared; dust-adhesive (dry), humified, wet mopping, and regular wet washing (RWW) without a mop . The following tests were taken from the floor before and after cleaning: bacterial counts (colony forming units = CFU) and ATP (presence of organic materials), and from the air: CFU/m3 air, and particle counts/m3 air . Humified mopping and dry mopping reduced the bacterial counts from the floor by 75% and 55% respectively (p = 0.005 and p = 0.014, using contact medium) . The wet mopping had no statistically significant effect, while the wet washing even increased the CFU on the floor by 35-50% (p = 0.017 with contact medium, and p = 0.028 with petrifilm) . The two wet methods were the most effective, however, in removing organic materials from the floor; 65% to 70% reduction (p = 0.051 and p =0.008) . The CFU/m3 air was low both before (50-130 CFU/m3) and after (70-110 CFU/m3) cleaning . A slight increase in airborne particles was measured after dry mopping . Combined use of humified mopping and wet mopping is recommended, but is dependent on a well prepared and finished floor surface. Nucleic Acids Res, 1997 Feb 15, 25(4), 701 - 12 Comparative analysis of the genomes of the bacteria Mycoplasma pneumoniae and Mycoplasma genitalium; Himmelreich R et al.; The sequenced genomes of the two closely related bacteria Mycoplasma genitalium and Mycoplasma pneumoniae were compared with emphasis on genome organization and coding capacity . All the 470 proposed open reading frames (ORFs) of the smaller M.genitalium genome (580 kb) were contained in the larger genome (816 kb) of M.pneumoniae . There were some discrepancies in annotation, but inspection of the DNA sequences showed that the corresponding DNA was always present in M . pneumoniae . The two genomes could be subdivided into six segments . The order of orthologous genes was well conserved within individual segments but the order of these segments in both bacteria was different . We explain the different organization of the segments by translocation via homologous recombination . The translocations did not disturb the continuous bidirectional course of transcription in both genomes, starting at the proposed origin of replication . The additional 236 kb in M.pneumoniae,compared with theM.genitalium genome, were coding for 209 proposed ORFs not identified in M.genitalium . Of these ORFs, 110 were specific to M.pneumoniae exhibiting no significant similarity to M.genitalium ORFs, while 76 ORFs were amplifications of ORFs existing mainly as single copies in M . genitalium . In addition, 23 ORFs containing a copy of either one of the three repetitive DNA sequences RepMP2/3, RepMP4 and RepMP5 were annotated in M.pneumoniae but not in M.genitalium,although similar DNA sequences were present . TheM.pneumoniae-specific genes included a restriction-modification system, two transport systems for carbohydrates, the complete set of three genes coding for the arginine dihydrolase pathway and 14 copies of the repetitive DNA sequence RepMP1 which were part of several different translated genes with unknown function. Ugeskr Laeger, 1997 Feb 10, 159(7), 952 - 5 {Influence of local air suction on the density of air-borne bacteria during cementation of alloplasties}; Enggaard TP et al.; At joint replacement operations local air suction is used to reduce the air pollution from organic solvents in the operation theatre during insertion of cement and prosthesis . In order to find out whether the local suction in an ultraclean-air operation theatre with laminar airflow influenced the number of colony forming units (cfu) of bacterial in vicinity of the wound, one m3 of air was sampled 20 cm and one metre from the wound before, during and after use of local suction during insertion of cement and prosthesis using a Sartorius membrane filter sampler . There was no significant difference between the groups in the numbers of cfu of bacteria found . It is concluded that use of local air suction over the operative area while cementing hip prosthesis does not affect the number of bacteria in the vicinity of the operation. Zygote, 1997 Feb, 5(1), 21 - 30 Virus-like particles, bacteria and microsporidia affect spindle-associated membranes in spermatocytes of Lepidoptera species; Wolf KW; Larval testes of four Lepidoptera species were examined using electron microscopy . The testes of one species, the Mediterranean mealmoth Ephestia kuehniella (Pyralidae), were devoid of intracellular pathogens and serve as a control . In this species, metaphase spindles of primary spermatocytes showed a thick layer of perispindle membranes . The membranes were structurally very similar to the agranular endoplasmic reticulum . Membranes of this type occurred also at high frequency throughout the spindle matrix . The analysis of larval testes of Pieris brassicae (Pieridae) revealed virus-like particles within spermatocytes . In another species, Philudoria potatoria (Lasiocampidae), the spermatocytes possessed intracellular bacteria . Whereas the pathogens were found within the germ cells in these species, a fourth species, Plutella xylostella (Plutellide), showed microsporidia within somatic cells of the testis sheath . In all the infected animals, the mass of perispindle membranes was reduced in comparison with spermatocytes of E . kuehniella . However, spindle structure appeared regular in the infected animals . This indicates that a thick layer of perispindle membranes is not decisive for spindle assembly and function in male meiosis of Lepidopera. Antonie Van Leeuwenhoek, 1997 Feb, 71(1-2), 59 - 67 Enzymology of the oxidation of ammonia to nitrite by bacteria; Hooper AB et al.; The enzymes which catalyze the oxidation of ammonia to nitrite by autotrophic bacteria are reviewed . A comparison is made with enzymes which catalyze the same reactions in methylotrophs and organotrophic heterotrophic bacteria. Protein Sci, 1997 Feb, 6(2), 464 - 8 Evidence for PDZ domains in bacteria, yeast, and plants; Ponting CP; Several dozen signaling proteins are now known to contain 80-100 residue repeats, called PDZ (or DHR or GLGF) domains, several of which interact with the C-terminal tetrapeptide motifs X-Ser/Thr-X-Val-COO- of ion channels and/or receptors . PDZ domains have previously been noted only in mammals, flies, and worms, suggesting that the primordial PDZ domain arose relatively late in eukaryotic evolution . Here, techniques of sequence analysis-including local alignment, profile, and motif database searches-indicate that PDZ domain homologues are present in yeast, plants, and bacteria . It is suggested that two PDZ domains occur in bacterial high-temperature requirement A (htrA) and one in tail-specific protease (tsp) homologues, and that a yeast htrA homologue contains four PDZ domains . Sequence comparisons suggest that the spread of PDZ domains in these diverse organisms may have occurred via horizontal gene transfer . The known affinity of Escherichia coli tsp for C-terminal polypeptides is proposed to be mediated by its PDZ-like domain, in a similar manner to the binding of C-terminal polypeptides by animal PDZ domains. Appl Environ Microbiol, 1997 Feb, 63(2), 743 - 8 Competition for cellobiose among three predominant ruminal cellulolytic bacteria under substrate-excess and substrate-limited conditions; Shi Y et al.; The ruminal cellulolytic bacteria Ruminococcus flavefaciens FD-1 and Fibrobacter succinogenes S85 coexisted in substrate-excess coculture with about equal population size, but R . flavefaciens outcompeted F . succinogenes for cellobiose in the substrate-limited cocultures whether the two strains were coinoculated or a steady-state culture of F . succinogenes was challenged by R . flavefaciens . This outcome of competition between these two strains is due to a classical pure and simple competition mechanism based on affinity for cellobiose . Although the population size of F . succinogenes was much higher (> 70%) than that of another cellulolytic species, Ruminococcus albus 7 in substrate-excess coculture, F . succinogenes was replaced by a population of R . albus in the substrate-limited coculture in both coinoculation and challenge experiments . R albus outcompeted F . succinogenes, apparently due to selection in the chemostat of a population of R . albus with a higher affinity for cellobiose . R . albus also outcompeted R . flavefaciens under substrate-limited conditions. Appl Environ Microbiol, 1997 Feb, 63(2), 734 - 42 Competition for cellulose among three predominant ruminal cellulolytic bacteria under substrate-excess and substrate-limited conditions; Shi Y et al.; Three predominant ruminal cellulolytic bacteria (Fibrobacter succinogenes S85, Ruminococcus flavefaciens FD-1, and Ruminococcus albus 7) were grown in different binary combinations to determine the outcome of competition in either cellulose-excess batch culture or in cellulose-limited continuous culture . Relative populations of each species were estimated by using signature membrane-associated fatty acids and/or 16S rRNA-targeted oligonucleotide probes . Both F . succinogenes and R . flavefaciens coexisted in cellulose-excess batch culture with similar population sizes (58 and 42%, respectively; standard error, 12%) . By contrast, under cellulose limitation R . flavefaciens predominated (> 96% of total cell mass) in coculture with F . succinogenes, regardless of whether the two strains were inoculated simultaneously or whether R . flavefaciens was inoculated into an established culture of F . succinogenes . The predominance of R . flavefaciens over F . succinogenes under cellulose limitation is in accord with the former's more rapid adherence to cellulose and its higher affinity for cellodextrin products of cellulose hydrolysis . In batch cocultures of F . succinogenes and R . albus, the populations of the two species were similar . However, under cellulose limitation, F . succinogenes was the predominant strain (approximately 80% of cell mass) in cultures simultaneously coinoculated with R . albus . The results from batch cocultures of R . flavefaciens and R . albus were not consistent within or among trials: some experiments yielded monocultures of R . albus (suggesting production of an inhibitory agent by R . albus), while others contained substantial populations of both species . Under cellulose limitation, R . flavefaciens predominated over R . albus (85 and 15%, respectively), as would be expected by the former's greater adherence to cellulose . The retention of R . albus in the cellulose-limited coculture may result from a combination of its ability to utilize glucose (which is not utilizable by R . flavefaciens), its demonstrated ability to adapt under selective pressure in the chemostat to utilization of lower concentrations of cellobiose, a major product of cellulose hydrolysis, and its possible production of an inhibitory agent. Appl Environ Microbiol, 1997 Feb, 63(2), 644 - 51 Development and application of 16S rRNA-targeted probes for detection of iron- and manganese-oxidizing sheathed bacteria in environmental samples; Siering PL et al.; Comparative sequence analysis of the 16S rRNA genes from several Leptothrix and Sphaerotilus strains led to the design of an oligonucleotide probe (PS-1) based on a sequence within the hypervariable region 1 specific for four Leptothrix strains and for one of the four Sphaerotilus natans strains examined . Another probe (PSP-6) was based on a sequence within the hypervariable region 2 . PSP-6 was specific for one of the two evolutionary lineages previously described for Leptothrix spp . (P . L . Siering and W . C . Ghiorse, Int . J . Syst . Bacteriol . 46:173-182, 1996) . Fluorescein-labeled oligonucleotide probes were synthesized, and their specificity for fluorescence in situ hybridization identification was confirmed by a laser scanning microscopy technique (W . C . Ghiorse, D . N . Miller, R . L . Sandoli, and P . L . Siering, Microsc . Res . Tech . 33:73-86, 1996) to compare whole-cell hybridizations of closely related bacteria . Probe specificity was also tested in dot blot against total RNA isolated from four Leptothrix strains, four Sphaerotilus strains, and 15 other members of the class Proteobacteria . When the probes were tested on samples from the Sapsucker Woods wetland habitat where Leptothrix spp . are thought to play a role in manganese and iron oxidation, positive signals were obtained from several sheathed filamentous bacteria including some that were morphologically similar to previously isolated strains of "Leptothrix discophora." Other unknown filamentous sheathed bacteria also gave strong positive signals . This work provides a foundation for future studies correlating the presence of members of the Leptothrix-Sphaerotilus group of sheathed bacteria with manganese and iron oxidation activity in habitats where biological iron and manganese oxidation are important environmental processes. Nucleic Acids Res, 1997 Feb 1, 25(3), 675 - 6 An effective method of RNA extraction from bacteria refractory to disruption, including mycobacteria; Mangan JA et al.; A high yield, rapid and simple procedure is described for extracting RNA from mycobacteria and other micro-organisms refractory to disruption . The method yielded 20 microg RNA/109 Mycobacterium bovis BCG, more than 10 times greater than our previous method . Intact full length hsp 70 (dnaK) mRNA was detected by northern blotting and quantitated after heat shock by slot blot hybridisation. J Bacteriol, 1997 Feb, 179(3), 576 - 82 Barriers to heterologous expression of a selenoprotein gene in bacteria; Tormay P et al.; The specificity parameters counteracting the heterologous expression in Escherichia coli of the Desulfomicrobium baculatum gene (hydV) coding for the large subunit of the periplasmic hydrogenase which is a selenoprotein have been studied . hydV'-'lacZ fusions were constructed, and it was shown that they do not direct the incorporation of selenocysteine in E . coli . Rather, the UGA codon is efficiently suppressed by some other aminoacyl-tRNA in an E . coli strain possessing a ribosomal ambiguity mutation . The suppression is decreased by the strA1 allele, indicating that the hydV selenocysteine UGA codon has the properties of a "normal" and suppressible nonsense codon . The SelB protein from D . baculatum was purified; in gel shift experiments, D . baculatum SelB displayed a lower affinity for the E . coli fdhF selenoprotein mRNA than E . coli SelB did and vice versa . Coexpression of the hydV'-'lacZ fusion and of the selB and tRNA(Sec) genes from D . baculatum, however, did not lead to selenocysteine insertion into the protein, although the formation of the quaternary complex between SelB, selenocysteyl-tRNA(Sec), and the hydV mRNA recognition sequence took place . The results demonstrate (i) that the selenocysteine-specific UGA codon is readily suppressed under conditions where the homologous SelB protein is absent and (ii) that apart from the specificity of the SelB-mRNA interaction, a structural compatibility of the quaternary complex with the ribosome is required. Curr Microbiol, 1997 Feb, 34(2), 103 - 9 Isolation and Characterization of Dehalogenases from2,2-Dichloropropionate-Degrading Soil Bacteria Schwarze R, Brokamp A, Schmidt FRJ. Five bacterial strains were isolated from polluted soilscapable of degrading 2,2-dichloropropionate . In crude extracts, dehalogenaseactivity against haloacetates and longer-chained 2-haloalkanoic acids couldbe detected . Results from activity staining indicated that all bacterialstrains expressed a single dehalogenase . In further biochemicalcharacterization, two types of D,L-specific 2-haloalkanoic acid dehalogenaseswere described, which are different from each other not only in molecularweight and electrophoretic mobility, but also in sensitivity towards thiolreagents . Dehalogenases of these strains have been shown to be inducible andare catalyzing halide hydrolysis with inversion of product configuration. J Biol Chem, 1997 Jan 17, 272(3), 1670 - 6 Pleiotropic effects of puf interposon mutagenesis on carotenoid biosynthesis in Rubrivivax gelatinosus . A new gene organization in purple bacteria; Ouchane S et al.; Rubrivivax gelatinosus mutants affected in the carotenoid biosynthesis pathways were created by interposon mutagenesis within the puf operon . Genetic and biochemical analysis of several constructed mutants suggest that at least crtC is localized downstream of the puf operon and that it is cotranscribed with this operon . Sequence analysis confirmed the genetic data and showed the presence of crtD and crtC genes downstream of the puf operon, a localization different from that known for other purple bacteria . Inactivation of the crtD gene indicated that the two crt genes are cotranscribed and that they are involved not only in the hydroxyspheroidene biosynthesis pathway as in Rhodobacter sphaeroides and R . capsulatus, but also in the spirilloxanthin biosynthesis pathway . Carotenoid genes implicated in the spirilloxanthin biosynthesis pathway were thus identified for the first time . Furthermore, analysis of carotenoid synthesis in the mutants gave genetic evidence that crtD and crtC genes are cotranscribed with the puf operon using the oxygen-regulated puf promoter. J Basic Microbiol, 1997, 37(3), 205 - 11 Degradation of dimeric lignin model compounds by aerobic bacteria isolated from the hindgut of xylophagous termites; Kuhnigk T et al.; The capability of the intestinal flora from the gut of xylophagous termites of degrading lignin model compounds was investigated . Different dimeric lignin model compounds-degrading bacteria were obtained from the hindgut flora of Mastotermes darwiniensis Froggatt, Reticulitermes santonensis Feytaud, Nasutitermes nigriceps Haldeman and Zootermopsis angusticollis Hagen . In the presence of oxygen dimeric model compounds were degraded by all isolates . This indicates that the hindgut flora of termites is basically able to produce substrate for their host from aromatic extractives of wood. Membr Cell Biol, 1997, 11(1), 1 - 16 Effect of hydration on the structure, dynamics and function of photosynthetic membranes of purple bacteria; Aksyonov SI et al.; NMR spectra and relaxation times T1 and T2 for 31P in membranes of Rhodobacter sphaeroides were investigated at different relative humidity levels . The results are compared to the hydration curves, fatty acid composition and the structure-dynamic and functional characteristics of the membranes of photosynthetic bacteria Rb . sphaeroides, Rhodospirillum rubrum and Ectothiorhodospira shaposhnikovii . The differences in the state of lipid phase of these membranes are revealed under low humidity, and this is conducive to variability of their structural dynamic and functional characteristics during the hydration process . Based on the results obtained and the data on model systems, four stages of hydration process are distinguished with different effects on the structure and dynamics of membrane components . These stages are: hydration of a portion of polar groups, involvement of water molecules in the hydrogen bonds within macromolecules and the lipid phase, hydration of all polar groups with the appearance of water with high dielectric constant thus making possible the lateral diffusion within the membrane and realization, through water participation, of conditions within organelles and cells required for the process regulation at these levels . The mechanism of water action on various membrane components and their dynamics at each stage are discussed, as well as the effect of different types of motion on the efficiency and regulation of electron transport in the photosynthetic chain of the membranes studied. Folia Microbiol (Praha), 1997, 42(3), 165 - 70 Diversity and specificity of protein-phosphorylating systems in bacteria; Cozzone AJ; Bacteria harbor three different protein-phosphorylating systems which regulate distinct physiological processes: first, the nucleotide-dependent system which modifies hydroxyl groups of amino acids in protein substrates; second, the two-component system which involves both sensor kinase and response regulator; third, the phosphoenolpyruvate-dependent phosphotransferase system . These systems share a number of structural and functional similarities with the protein-phosphorylating systems of eukaryotes. Biosystems, 1997, 43(2), 83 - 95 A quantum-theoretical approach to the phenomenon of directed mutations in bacteria (hypothesis); Ogryzko VV; The Darwinian paradigm of biological evolution is based on the independence of genetic variations from selection which occurs afterwards . However, according to the phenomenon of directed mutations, some genetic variations occur mostly when the conditions favorable for their growth are created . I propose that the explanation of this phenomenon should not rely on any special 'mechanism' for the appearance of directed mutations, but rather should be based on the principles of quantum theory . I consider a physical model of adaptation whereby a polarized photon, passing through a polarizer, changes its polarization according to the angle of the polarizer . This adaptation occurs by selection of the 'fitted' polarized state which exists as a component of superposition in the initial state of the photon . However, since the same state of the incoming photon should be decomposed differently depending on the angle of the polarizer, in this case the set of variations subjected to selection depends upon the selective conditions themselves . This reveals the crucial difference between this model of adaptation and canonical Darwinian selection . Based on this analogy, the capacity of a cell to grow in particular conditions is considered an observable of the cell; the plating experiments are interpreted as measurement of this observable . The only nontrivial suggestion of the paper states that the cell, analogously to the polarized photon, may be in a state of superposition of eigenfunctions of the operator which represents this observable, and with some probability can appear as a mutant upon the measurement . Alternative growth conditions correspond to the decomposition of the same state vector into a different superposition, consistent with measurement of a different observable and appearance of different mutants . Thus, consistent with the suggested analogy, directed mutations are explained as a result of random choice from the set of outcomes determined by the environment. Mikrobiologiia, 1997 Jan-Feb, 66(1), 5 - 13 {Cell differentiation and its regulation during genetic transformation in bacteria}; Prozorov AA; Mechanisms determining cell differentiation at the intracellular and intercellular levels during genetic transformation of certain bacterial species are reviewed . The "predetermination" both of cell outer layers and of chromosomal DNA to transformation before interaction with the transforming DNA is discussed. Crit Rev Biotechnol, 1997, 17(1), 39 - 67 Xylanolytic enzymes from fungi and bacteria; Sunna A et al.; The development of new analytical techniques and the commercial availability of new substrates have led to the purification and characterization of a large number of xylan-degrading enzymes . Furthermore, the introduction of recombinant DNA technology has resulted in the selection of xylanolytic enzymes that are more suitable for industrial applications . For a successful integration of xylanases in industrial processes, a detailed understanding of the mechanism of enzyme action is, however, required . This review gives an overview of various xylanolytic enzyme systems from bacteria and fungi that have been described recently in more detail. J Appl Microbiol, 1997 Jan, 82(1), 39 - 47 Filtration of bacteria and yeast by ultrasound-enhanced sedimentation; Hawkes JJ et al.; Continuous flow filtration of suspensions of eukaryotic cells by ultrasonic standing wave enhanced sedimentation has recently been reported . The filtration efficiency for Escherichia coli in such a filter has been characterized at frequencies of 1 and 3 MHz in the present work and compared with results for Saccharomyces cerevisiae . The yeast can be filtered at greater than 99% efficiency at a flow rate of 5 ml min-1 at either frequency . The filtration efficiency of the smaller E . coli at 3 MHz is in excess of 80% at concentrations in the region of 10(10) ml-1 but decreased at lower concentrations . However, E . coli in a mixed suspension with yeast were, because of inter-particle interactions, removed with the filtrate at an efficiency ranging from 80 to 50% over the eight orders of bacterial concentrations tested (down to 10(3) ml-1) at 3 MHz . Quantitative considerations show that poor filtration of pure suspensions of the smaller cells at the lower frequency arises because, at reasonable flow rates, the residence time is not sufficient for the cells to reach the pressure nodal cell concentration regions . The filtration efficiencies of both cell types are comparable at 3 MHz . It is suggested that the more comparable efficiencies arise because concentration regions are narrower at the high frequency and Stokes drag by the filter bulk flow inhibits sedimentation of the concentrated cells. J Periodontal Res, 1997 Jan, 32(1 Pt 2), 200 - 5 Interactions between periodontopathogenic bacteria and cytokines; Fletcher J et al.; Cytokines produced in response to plaque bacteria clearly play a key role in the periodontal diseases . However, we know very little about the interactions between cytokines and periodontopathogenic bacteria . The aims of this study were to determine whether the key pro-inflammatory cytokines interleukin-1 beta (IL-1 beta) and IL-6 could affect the growth of Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis and to determine whether these organisms could hydrolyse IL-1 beta, IL-6 or the anti-inflammatory IL-1 receptor antagonist (IL-1ra) . Culture medium containing up to 100 ng/ml of IL-1 beta or IL-6 was inoculated with A . actinomycetemcomitans (serotypes a, b and c) or P . gingivalis and growth was monitored by measuring changes in electrical conductivity every 3 min for up to 48 h . IL-1 beta, IL-6 or IL-1ra were added to culture supernatants and incubated for up to 24 h . Samples were taken at various times, analysed by SDS-PAGE and the separated proteins transferred by Western blotting to PVDF membranes and probed with anti-cytokine antibodies . None of the cytokines tested had any effect on the rate of growth or yield of A . actinomycetemcomitans or P . gingivalis . Supernatants from P . gingivalis cultures, but not those from A . actinomycetemcomitans, hydrolysed IL-1 beta, IL-6 and IL-1ra . The hydrolysate from the P . gingivalis supernatant-treated IL-1 beta was unable to stimulate the release of IL-6 from human gingival fibroblasts showing that it had lost biological activity . These results suggest that P . gingivalis can perturb the cytokine network, not only by stimulating the release of cytokines from host cells, but also by removing them from its local environment. Appl Environ Microbiol, 1997 Jan, 63(1), 239 - 45 Evidence for production of paralytic shellfish toxins by bacteria associated with Alexandrium spp . (Dinophyta) in culture; Gallacher S et al.; A substantial proportion of bacteria from five Alexandrium cultures originally isolated from various countries produced sodium channel blocking (SCB) toxins, as ascertained by mouse neuroblastoma assay . The quantities of SCB toxins produced by bacteria and dinoflagellates were noted, and the limitations in comparing the toxicities of these two organisms are discussed . The chemical nature of the SCB toxins in selected bacterial isolates was determined as paralytic shellfish toxins by pre- and postcolumn high-performance liquid chromatography, capillary electrophoresis-mass spectrometry, and enzyme immunoassay. Nord Med, 1997 Jan, 112(1), 10 - 3 {The body's defense against intracellular bacteria}; Tarnvik A; The separation of the two pathways of differentiation of CD4 T cells is fundamental to an understanding of host defence against intracellular bacteria . Th1 cells, but not Th2 cells, promote effective host response . Elucidation of the mechanisms responsible for the differentiation of Th1 and Th2 cells will facilitate the development of subcellular vaccines against intracellular bacteria. Tissue Antigens, 1997 Jan, 49(1), 23 - 8 HLA-B27 presents a peptide from a polymorphic region of its own molecule with homology to proteins from arthritogenic bacteria; Garcia F et al.; A possible mechanism for the pathogenesis of HLA-B27-associated spondyloarthropathies is that peptides from arthritogenic bacteria with homology to endogenous self-peptides presented by HLA-B27, including those derived from HLA-B27 itself, could elicit an autoimmune T-cell response upon infection . We report here that an undecamer corresponding to the polymorphic region of HLA-B27 spanning residues 169-179 is presented in vivo by the B*2701, B*2704 and B*2706 subtypes, but was not detected in the B*2703-bound peptide pool . This peptide binds to B*2705 in vitro with sufficient affinity to allow its natural presentation by this subtype, but it binds with low affinity to B*2703 . In spite of homology of this peptide to proteins from arthritogenic bacteria, its binding specificity does not correlate with current evidence concerning association of HLA-B27 subtypes to ankylosing spondylitis, suggesting that presentation of this peptide is not the critical feature that determines linkage of HLA-B27 to this disease. Biol Pharm Bull, 1997 Jan, 20(1), 47 - 53 Production of plant non-protein amino acids by recombinant enzymes of sequential biosynthetic reactions in bacteria; Saito K et al.; We constructed the co-expression vector, pFK4, in which two cDNAs encoding serine acetyltransferase (SATase) and beta-(pyrazol-1-yl)-L-alanine/L-cysteine synthase (beta-PA/CSase) from Citrullus vulgaris (watermelon) were over-expressed under the transcriptional control of T7 promoter in Escherichia coli . Accumulation of both SATase and beta-PA/CSase in soluble extracts of E . coli was confirmed by immunoblotting . The high enzymatic activities of SATase and L-cysteine synthase (CSase) were detected in cell-free extracts of E . coli carrying pFK4 . The activities of the formation of beta-PA and L-mimosine, plant non-protein amino acids, from O-acetyl-L-serine (OAS) and the precursor heterocyclic compounds, pyrazole and 3,4-dihydroxypyridine, were also found in the extracts . beta-PA was also produced in vivo from L-serine and pyrazole as precursors by E . coli cells transformed with pFK4 . beta-PA was accumulated mainly in the extra-cellular culture medium . The pronounced accumulation of L-cysteine and L-methionine was observed in the cells transformed with pFK4 . Additionally, we also constructed vectors which carried chimeric genes encoding fusion proteins of SATase and beta-PA/CSase . However, the fusion proteins tended to form insoluble inclusion bodies and thus to exhibit only weak enzymatic activities . The successful results of pFK4 shows the way to create a new sequential biosynthetic pathway of plant specific amino acids in bacterial cells by means of recombinant DNA technology. Int J Syst Bacteriol, 1997 Jan, 47(1), 217 - 9 Transfer of the bacteriochlorophyll b-containing phototrophic bacteria Rhodopseudomonas viridis and Rhodopseudomonas sulfoviridis to the genus Blastochloris gen . nov; Hiraishi A; The phylogenetic positions of the bacteriochlorophyll (BChl) b-producing budding phototrophic bacteria Rhodopseudomonas viridis and Rhodopseudomonas sulfoviridis were studied on the basis of 16S rRNA gene sequence information . These bacteria formed a tight cluster with the genus Rhodoplanes as a sister group within the alpha-2 subgroup of the Proteobacteria . Genomic DNA-DNA hybridization assays showed that R . viridis and R . sulfoviridis were closely related but were different species . Creation of the genus Blastochloris gen . nov . is proposed to accommodate these BChl b-producing species of phototrophic bacteria. Anal Chem, 1997 Jan 1, 69(1), 16 - 20 Genetically engineered bacteria: electrochemical sensing systems for antimonite and arsenite; Scott DL et al.; A bacterial sensing system that responds selectively to antimonite and arsenite has been investigated . The bacteria used in these studies have been genetically engineered to produce the enzyme beta-galactosidase in response to these ions . This is accomplished by using a plasmid that incorporates the gene for beta-galactosidase (reporter gene) under the control of the promoter of the ars operon . This plasmid also encodes for the ArsR protein, a regulatory protein of the ars operon, which, in the absence of antimonite or arsenite, restricts the expression of beta-galactosidase . In the presence of antimonite or arsenite the ArsR protein is released from the operator/ promoter region of the ars operon and beta-galactosidase is expressed . The activity of this enzyme was monitored electrochemically using p-aminophenyl beta-D-galactopyranoside as the substrate . The bacterial sensing system responds selectively to arsenite and antimonite (and to a lesser extent arsenate) and shows no significant response to phosphate, sulfate, nitrate, and carbonate. Oral Dis, 1996 Dec, 2(4), 253 - 62 Rheumatoid factor from periodontitis patients cross-reacts with epitopes on oral bacteria; The J et al.; OBJECTIVES: The objective of this study was to determine the antigenic specificity of rheumatoid factor (RF) that had previously been reported in the serum of patients with periodontitis . DESIGN: IgM-RF was isolated from the serum of five RF-seropositive rheumatoid arthritis patients and 14 RF-seropositive periodontitis and examined for specificity to human IgG and selected oral bacteria . METHODS: IgM-RF was prepared by affinity chromatography on human IgG columns . Human IgG antibody to Capnocytophaga gingivalis, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans was isolated by binding and elution of antibody from the bacteria, followed by purification using a rabbit anti-IgG affinity column . MAIN OUTCOME MEASURE: Binding of the isolated