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PubMed2001

Lachnobacterium bovis gen. nov., sp. nov., a novel bacterium isolated from the rumen and faeces of cattle.

Phenotypic and phylogenetic analysis was performed on four strains of a previously undescribed Gram-positive, rod-shaped, anaerobic bacterium isolated from the rumen and faeces of cattle. This bacterium fermented glucose primarily to lactic acid along with minor amounts of acetic and butyric acids. The four strains produced a temperature-sensitive bacteriocin-like inhibitory substance. Comparative 16S rRNA gene sequence analysis indicated that the bacterium was a member of the clostridial XIVa cluster of the low-G+C content Gram-positive bacteria. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be assigned to a new genus, Lachnobacterium, as Lachnobacterium bovis gen. nov., sp. nov. The type strain is YZ 87T (= ATCC BAA-151T = DSM 14045T = LRC 5382T). Its G+C content is 33.9 mol %.

Anaerobiosis↗
PubMed2001

Muricauda ruestringensis gen. nov., sp. nov., a facultatively anaerobic, appendaged bacterium from German North Sea intertidal sediment.

A gram-negative, facultatively anaerobic bacterium with appendages was isolated from continuous cultures with a seawater-sediment suspension containing hexadecane as the sole carbon source. Although this organism was isolated from a hexadecane-degrading bacterial community, it was not able to degrade hexadecane. However, this bacterium was able to use different sugars and amino acids for growth, indicating that it probably profits from the lysis or from products like surfactants of other cells in the community. 16S rDNA analysis demonstrated that the isolated strain is phylogenetically related to the family Flavobacteriaceae of the phylum 'Cytophaga-Flavobacterium-Bacteroides'. Evidence based on phenotypic characteristics and 16S rDNA analysis supports the conclusion that this bacterium is distinct from its nearest relative, Zobellia uliginosa (90.72% similarity in 16S rRNA gene sequence), and from the other genera of the Flavobacteriaceae. It is therefore proposed that the isolated marine bacterium represents a novel taxon, designated Muricauda ruestringensis gen. nov., sp. nov. The type strain is strain B1T (= DSM 13258T = LMG 19739T).

Culture Media↗
PubMed1994

The utilization of thiocyanate as a nitrogen source by a heterotrophic bacterium: the degradative pathway involves formation of ammonia and tetrathionate.

A Gram-negative soil bacterium (isolate 26B) has been shown to utilize up to 100 mM thiocyanate as a source of nitrogen when supplied with glucose as the source of carbon and energy. During growth of isolate 26B with thiocyanate as the source of nitrogen, no ammonia, nitrate, nitrite, cyanide, cyanate, sulfate, sulfite, sulfide or carbonyl sulfide was detected in the growth medium. Growth of the bacterium on 14C-labelled thiocyanate (1.6 microCi) and glucose, yielded 14C-labelled carbon dioxide (0.9 microCi). The addition of 2.9 mM thiocyanate to a bacterial suspension in phosphate buffer (50 mM, pH 7.4) resulted in the utilization of 2.1 mM thiocyanate and the production of 2.0 mM ammonia. This activity was inducible and only occurred after growth of the bacterium with thiocyanate as the source of nitrogen. Tetrathionate (0.7 mM) was detected in the medium after the utilization of thiocyanate (2.4 mM) by a suspension of the bacterium in phosphate buffer, and thiosulfate (1.0 mM) was detected as an intermediate. The addition of sulfide or thiosulfate to the bacterial suspension also resulted in the formation of tetrathionate. The utilization of both of these compounds appeared to be constitutive. A pathway for thiocyanate utilization by isolate 26B is proposed which involves the hydrolysis of thiocyanate to produce cyanate and sulfide. The cyanate then undergoes further hydrolysis to form ammonia and carbon dioxide. The sulfide is ultimately oxidized to tetrathionate via a pathway which includes thiosulfate.

Ammonia↗
PubMed2006

Effectiveness of autochthonous bacterium and mycorrhizal fungus on Trifolium growth, symbiotic development and soil enzymatic activities in Zn contaminated soil.

AIMS: This study investigates how autochthonous micro-organisms [bacterium and/or arbuscular mycorrhizal (AM) fungi] affected plant tolerance to Zn contamination. METHODS AND RESULTS: Zinc-adapted and -nonadapted Glomus mosseae strains protected the host plant against the detrimental effect of Zn (600 microg g(-1)). Zn-adapted bacteria increased root growth and N, P nutrition in plants colonized by adapted G. mosseae and decreased the specific absorption rate (SAR) of Cd, Cu, Mo or Fe in plants colonized by Zn-nonadapted G. mosseae. Symbiotic structures (nodule number and extraradical mycelium) were best developed in plants colonized by those Zn-adapted isolates that were the most effective in increasing plant Zn tolerance. The bacterium also increased the quantity and quality (metabolic characteristics) of mycorrhizal colonization, with the highest improvement for arbuscular vitality and activity. Inocula also enhanced soil enzymatic activities (dehydrogenase, beta-glucosidase and phosphatase) and indol acetic acid (IAA) accumulation, particularly in the rhizosphere of plants inoculated with Zn-adapted isolates. CONCLUSIONS: Glomus mosseae strains have a different inherent potential for improving plant growth and nutrition in Zn-contaminated soil. The bacterium increased the potential of mycorrhizal mycelium as inoculum. SIGNIFICANCE AND IMPACT OF THE STUDY: Mycorrhizal performance, particularly that of the autochthonous strain, was increased by the bacterium and both contributed to better plant growth and establishment in Zn-contaminated soils.

Absorption↗
PubMed1993

Hydrogen formation from glycolate driven by reversed electron transport in membrane vesicles of a syntrophic glycolate-oxidizing bacterium.

Oxidation of glycolate to 2 CO2 and 3 H2 (delta G degrees' = +36 kJ/mol glycolate) by the proton-reducing, glycolate-fermenting partner bacterium of a syntrophic coculture (strain FlGlyM) depends on a low hydrogen partial pressure (pH2). The first reaction, glycolate oxidation to glyoxylate (E zero' = -92 mV) with protons as electron acceptors (E zero' = -414 mV), is in equilibrium only at a pH2 of 1 microPa which cannot be maintained by the syntrophic partner bacterium Methanospirillum hungatei; energy therefore needs to be spent to drive this reaction. Glycolate dehydrogenase activity (0.3-0.96 U.mg protein-1) was detected which reduced various artificial electron acceptors such as benzyl viologen, methylene blue, dichloroindophenol, K3[Fe(CN)6], and water-soluble quinones. Fractionation of crude cell extract of the glycolate-fermenting bacterium revealed that glycolate dehydrogenase, hydrogenase, and proton-translocating ATPase were membrane-bound. Menaquinones were found as potential electron carriers. Everted membrane vesicles of the glycolate-fermenting bacterium catalyzed ATP-dependent H2 formation from glycolate (30-307 nmol H2.min-1 x mg protein-1). Protonophores, inhibitors of proton-translocating ATPase, and the quinone analog antimycin A inhibited H2 formation from glycolate, indicating the involvement of proton-motive force to drive the endergonic oxidation of glycolate to glyoxylate with concomitant H2 release. This is the first demonstration of a reversed electron transport in syntrophic interspecies hydrogen transfer.

Adenosine Triphosphatases↗
PubMed1996

Surface-associated material from the bacterium Actinobacillus actinomycetemcomitans contains a peptide which, in contrast to lipopolysaccharide, directly stimulates fibroblast interleukin-6 gene transcription.

The oral commensal Gram-negative bacterium Actinobacillus actinomycetemcomitans is believed to be the causative organism of localized juvenile periodontitis, a disease in which there is rapid loss of alveolar bone supporting the teeth. Previously, we have reported that gentle saline extraction of this bacterium removed a loosely adherent proteinaceous fraction from the cell surface of the bacterium, which we have termed surface-associated material. This material contained potent bone-resorbing activity. We now report that surface-associated material is also a potent stimulator of cytokines, and in particular, interleukin-6 (IL-6) synthesis, while the lipopolysaccharide from this bacterium is only a weak stimulator of IL-6 synthesis by fibroblasts and monocytes. In contrast to enteric lipopolysaccharide (LPS), which induces fibroblast IL-1, IL-6 and tumour necrosis factor (TNF) alpha synthesis, surface-associated material stimulated gingival fibroblasts to synthesize only IL-6, with no induction of IL-1 or TNF (the normal inducers of IL-6 synthesis). Reverse transcriptase PCR also failed to detect mRNA for IL-1 or TNF in surface-associated-material-stimulated fibroblasts, although both mRNAs were present in Escherichia coli LPS-stimulated cells. Neutralizing antibodies to IL-1 and/or TNF or the natural IL-1 receptor antagonist (IL-1ra) inhibited enteric LPS-induced IL-6 synthesis, but did not inhibit surface-associated-material-induced synthesis. In addition, dexamethasone, which completely suppressed LPS-induced IL-6 synthesis, only inhibited surface-associated-material-induced IL-6 synthesis by 50%. This suggests that the active constituent in the surface-associated material stimulates IL-6 gene transcription by a transcriptional control mechanism distinct to that of E. coli LPS. The IL-6 stimulating activity of the surface-associated material is inhibited by both heat and trypsin, suggesting that it is proteinaceous. The activity has been isolated using anion-exchange, reverse-phase and size-exclusion HPLC. The active moiety is a peptide of molecular mass 2kDa which may be the product of a bacterial short open reading frame.

Aggregatibacter actinomycetemcomitans↗
PubMed2005

A Mycobacterium avium PPE gene is associated with the ability of the bacterium to grow in macrophages and virulence in mice.

PPE and PE gene families, which encode numerous proteins of unknown function, account for 10% of Mycobacterium tuberculosis genome. Mycobacterium avium genome has similar PPE and PE gene families. Using a temperature-sensitive phage phAE94 transposon mutagenesis system, a M. avium transposon library was created in the strain MAC109. Screening of individual mutants in human U937 macrophages for the ability to replicate intracellularly, we identified several attenuated clones. One of them, the 2D6 mutant, has a transposon interrupting a PPE gene (52% homologous to Rv 1787 in M. tuberculosis) was identified. The mutant and the wild-type strain had comparable ability to enter macrophages. Challenge of mice with the 2D6 mutant resulted in approximately 1 log and 2 log fewer bacteria in the spleen, at 1 and 3 weeks after infection, compared with the wild-type bacterium. The 2D6 mutant grows like the wild-type bacterium in vitro. Vacuoles containing the 2D6 mutant acidified to pH 4.8; whereas, vacuoles containing wild-type bacterium were only slightly acidic. It was also observed that, in contrast to the wild-type bacterium, the 2D6 mutant did not prevent phagosome-lysosome fusion, and it is only expressed within macrophage but not in 7H9 broth. These results revealed a role for this PPE gene in the growth of M. avium in macrophages and in virulence in mice.

Animals↗
PubMed1999

Effects of antibiotics on the early infection process of a macronuclear endosymbiotic bacterium Holospora obtusa of Paramecium caudatum.

We examined the effects of antibiotics involved in bacterial DNA, RNA and protein synthesis and host protein synthesis on the early infection process of the bacterium Holospora obtusa, a macronucleus-specific symbiont of the ciliate Paramecium caudatum. Infection of the host macronucleus by the bacterium was not inhibited by mitomycin C, rifampicin and chloramphenicol. However, ingestion of the bacterium into the host digestive vacuoles and escape of the bacterium from the vacuoles to the host cytoplasm were significantly arrested with emetine. The results suggest that newly synthesized host proteins play an important role in the early infection process.

Animals↗
PubMed1979

Electron microscopy of a filamentous, segmented bacterium attached to the small intestine of mice from a laboratory animal colony in Denmark.

A filamentous, segmented bacterium was observed in the small intestine of the SSC:AH stock of mice from the Statens Seruminstitut (Denmark) animal colony but was absent in golden hamsters and guinea pigs from the same colony. The bacterium is attached to the epithelial cell by a special segment (holdfast) and causes specific changes in the epithelial cell at the site of attachment. Once attached the bacterium appears to undergo a complex life cycle which involves the development of a long filament divided into a number of segments within which holdfasts or spores are formed. This organism is morphologically identical to a bacterium found in mice and rats in the USA, but this is the first report of such an infection in Europe.

Animals↗
PubMed1986

Growth characteristics of a novel nitrogen-fixing cellulolytic bacterium.

Growth characteristics of a cellulolytic nitrogen-fixing bacterium isolated from a marine shipworm by Waterbury et al. (J. B. Waterbury, C. B. Calloway, and R. D. Turner, Science 221:1401-1403, 1983) are described. When grown microaerobically, the bacterium exhibited doubling times of about 2 days in cellulose-supplemented synthetic medium devoid of combined nitrogen. Maximum growth was reached 12 to 16 days after inoculation. Growth optima for pH, temperature, and NaCl concentration were 8.5, 30 to 35 degrees C, and 0.3 M, respectively. During growth the bacterium produced succinic acid (0.026%) and acetic acid (0.010%). Formic acid (0.010%) was produced during the stationary growth phase. No growth was observed when glucose was the sole carbon source. Cellobiose supported weak growth, while longer-chain-length cellodextrins supported extensive growth. Analysis of residual carbohydrates in the medium during growth indicated that the bacterium catabolized a terminal glucose moiety from the cellodextrin chain.

Journal Article↗
PubMed1988

Mineralization of carbofuran by a soil bacterium.

A bacterium, tentatively identified as an Arthrobacter sp., was isolated from flooded soil that was incubated at 35 degrees C and repeatedly treated with carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl N-methylcarbamate). This bacterium exhibited an exceptional capacity to completely mineralize the ring-labeled C in carbofuran to CO(2) within 72 to 120 h in a mineral salts medium as a sole source of carbon and nitrogen under aerobic conditions. Mineralization was more rapid at 35 degrees C than at 20 degrees C. No degradation of carbofuran occurred even after prolonged incubation under anaerobic conditions. The predicted metabolites of carbofuran, 7-phenol (2,3-dihydro-2,2-dimethyl-7-benzofuranol) and 3-hydroxycarbofuran, were also metabolized rapidly. 7-Phenol, although formed during carbofuran degradation, never accumulated in large amounts, evidently because of its further metabolism through ring cleavage. The bacterium readily hydrolyzed carbaryl (1-naphthyl N-methylcarbamate), but its hydrolysis product, 1-naphthol, resisted further degradation by this bacterium.

Journal Article↗
PubMed1997

Isolation and Characterization of Strain MMB-1 (CECT 4803), a Novel Melanogenic Marine Bacterium.

A novel marine melanogenic bacterium, strain MMB-1, was isolated from the Mediterranean Sea. The taxonomic characterization of this strain indicated that it belongs to the genus Alteromonas. Under in vivo conditions, L-tyrosine was the specific monophenolic precursor for melanin synthesis. This bacterium contained all types of activities associated with polyphenol oxidases (PPOs), cresolase (EC 1.18.14.1), catecholase (EC 1.10.3.1), and laccase (EC 1.10.3.2). These activities were due to the presence of two different PPOs. The first one showed all the enzymatic activities, but it was not involved in melanogenesis in vivo, since amelanogenic mutant strains obtained by nitrosoguanidine treatment contained levels of this PPO similar to that of the wild-type MMB-1 strain. The second PPO showed cresolase and catecholase activities but no laccase, and it was involved in melanogenesis, since this enzyme was lost in amelanogenic mutant strains. This PPO was strongly activated by sodium dodecyl sulfate below the critical micelle concentration, and it is a tyrosinase-like enzyme showing a lag period in its tyrosine hydroxylase activity that could be avoided by small amounts of L-dopa. This is the first report of a bacterium that contains two PPOs and also the first report of a pluripotent PPO showing all types of oxidase activities. The bacterium and the pluripotent PPO may be useful models for exploring the roles of PPOs in cellular physiology, aside from melanin formation. On the other hand, the high oxidizing capacity of the PPO for a wide range of substrates could make possible its application in phenolic biotransformations, food processing, or the cosmetic industry, where fungal and plant PPOs are being used.

Journal Article↗
PubMed2002

Identification of a bacterium that specifically catalyzes the reductive dechlorination of polychlorinated biphenyls with doubly flanked chlorines.

A microorganism whose growth is linked to the dechlorination of polychlorinated biphenyls (PCBs) with doubly flanked chlorines was identified. Identification was made by reductive analysis of community 16S ribosomal DNA (rDNA) sequences from a culture enriched in the presence of 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-CB), which was dechlorinated at the para position. Denaturing gradient gel electrophoresis (DGGE) analysis of total 16S rDNA extracted from the culture led to identification of three operational taxonomic units (OTUs 1, 2, and 3). OTU 1 was always detected when 2,3,4,5-CB or other congeners with doubly flanked chlorines were present and dechlorinated. Only OTUs 2 and 3 were detected in the absence of PCBs and when other PCBs (i.e., PCBs lacking doubly flanked chlorines) were not dechlorinated. Partial sequences of OTUs 2 and 3 exhibited 98.2% similarity to the sequence of "Desulfovibrio caledoniensis" (accession no. DCU53465). A sulfate-reducing vibrio isolated from the culture generated OTUs 2 and 3. This organism could not dechlorinate 2,3,4,5-CB. From these results we concluded that OTU 1 represents the dechlorinating bacterium growing in a coculture with a Desulfovibrio sp. The 16S rDNA sequence of OTU 1 is most similar to the 16S rDNA sequence of bacterium o-17 (89% similarity), an ortho-PCB-dechlorinating bacterium. The PCB dechlorinator, designated bacterium DF-1, reductively dechlorinates congeners with doubly flanked chlorines when it is supplied with formate or H(2)-CO(2) (80:20).

Bacteria↗
PubMed2002

Bacterium-induced CXCL10 secretion by osteoblasts can be mediated in part through toll-like receptor 4.

Two common pathogens known to cause bone infection, Salmonella and Staphylococcus aureus, were investigated to determine their abilities to induce chemokine expression in cultured mouse and human osteoblasts. While these cells are responsible for bone formation, we were surprised to find that they could respond to bacterial infection by upregulating expression of the chemokine CXCL10 (IP-10). However, there were significant differences in the abilities of the gram-negative bacterium Salmonella and the gram-positive bacterium S. aureus to induce expression of CXCL10. Reverse transcription-PCR and enzyme-linked immunosorbent assay analyses showed high levels of Salmonella-induced CXCL10 mRNA and protein expression, respectively, whereas the osteoblast response to S. aureus was significantly less. Consistent with these findings, Salmonella-derived lipopolysaccharide (LPS), but not S. aureus-derived peptidoglycan, could induce expression of CXCL10. An antibody against toll-like receptor 4 (TLR4) could block the LPS-induced CXCL10 production, demonstrating the functional expression of TLR4 by osteoblasts. Despite the inducible nature of TLR2 mRNA expression by bacterium-infected osteoblasts, peptidoglycan failed to stimulate CXCL10 secretion. Immunofluorescent staining of bacterium-infected calvaria (i.e., skull bone) demonstrated the presence of CXCL10 in osteoblasts. The fact that osteoblasts did not express CXCR3 mRNA, whereas T lymphocytes can express high levels of this receptor, suggests that osteoblast-derived CXCL10 may recruit T lymphocytes to the sites of bone infections.

Animals↗
PubMed1962

Combination of two types of transmissible drug-resistance factors in a host bacterium.

Mitsuhashi, Susumu (Gunma University, Maebashi, Japan), Kenji Harada, Hajime Hashimoto, Mitsuo Kameda, and Mitsue Suzuki. Combination of two types of transmissible drug-resistance factors in a host bacterium. J. Bacteriol. 84:9-16. 1962.-When two types of R factor, R(TC) and R (CM.SM.SA), or R(TC) and R (CM), were brought together in a host bacterium by superinfection with both factors, loss of either one or both factors was found. In the imperfectly stable existence of both factors in a host bacterium, both factors were transmitted separately by conjugation. As the result of interaction between the two types of R factor present in a host bacterium, recombinant factors were formed, R(25) (TC.CM.SM.SA) and R(31) (CM.TC). The recombinant factors were able to transfer their resistance by conjugation. They were also transduced as one unit into Escherichia coli K12 by Plke phage in the same fashion as the original R(11) (TC.CM.SM.SA) and R(14) (CM.TC) factors independently isolated from dysenteric patients.

Bacteria↗
PubMed1981

Measurement of immunoglobulin M, immunoglobulin G, and immunoglobulin A antibodies against Yersinia enterocolitica by enzyme-linked immunosorbent assay: comparison of lipopolysaccharide and whole bacterium as antigen.

An enzyme-linked immunosorbent assay (ELISA) for the detection and quantitation of human immunoglobulin M (IgM), IgG, and IgA antibodies against Yersinia enterocolitica by using lipopolysaccharides as antigens is described. The results obtained with the lipopolysaccharide ELISA were compared with the results of the whole bacterium ELISA. The correlations observed were good for each immunoglobulin class. Cross-reactions between Y. enterocolitica serotypes O:3 and O:9, Yersinia pseudotuberculosis IA, and Brucella abortus were studied by human and rabbit antisera in the whole bacterium and lipopolysaccharide ELISAs and by rabbit antisera using ELISA inhibition. The greatest cross-reactivity observed was that of the anti-Brucella serum with Y. enterocolitica O:9 in the whole bacterium ELISA. In the lipopolysaccharide ELISA this cross-reaction was not demonstrable with the rabbit antiserum, but it was strong with the human antiserum. However, differential diagnosis was possible with ELISA inhibition. On the basis of our experience, we are now routinely using whole bacterium ELISA for the determination of class-specific Yersinia antibodies, and potential cross-reactions are controlled by the ELISA inhibition.

Antibodies, Bacterial↗
PubMed1989

Pneumonia and meningitis caused by a new nonfermentative unknown gram-negative bacterium.

Seven isolates of an unclassified bacterium resembling Flavobacterium spp. were characterized by growth requirements, microscopic examination, biochemical characteristics, antimicrobial susceptibility tests, protein profile analysis, and serologic data. The unclassified isolates were differentiated from Flavobacterium meningosepticum, Flavobacterium odoratum, Flavobacterium balustinum, Flavobacterium strain IIb, Chromobacterium violaceum, Aquaspirillum serpens, and Pseudomonas spp. The bacterium was a gram-negative rod with a polar flagellum. Protein profile analysis demonstrated two major protein bands present in the unclassified isolates that were absent from the Flavobacterium and Pseudomonas controls but present in the Aquaspirillum and Chromobacterium controls. However, no serologic cross-reactions were observed. Our results showed that the unclassified bacterium was distinct from any previously known genus of bacterium.

Bacteria↗
PubMed1996

Specific, nonradioactive detection of the NHP bacterium in Penaeus vannamei by in situ hybridization.

Necrotizing hepatopancreatitis (NHP) is a disease of farm-raised Pacific white shrimp (Penaeus vannamei) caused by a pleomorphic intracellular bacterium. A DNA probe that is specific for the etiologic agent of necrotizing hepatopancreatitis was devised and tested in an in situ hybridization assay. A procedure was developed for labeling a single-stranded DNA probe with digoxigenin by the polymerase chain reaction. The DNA probe encompasses the V1 and V2 variable regions of the 16S ribosomal RNA (rRNA) gene and is designed to hybridize to complementary sequences of the 16S rRNA of the NHP bacterium. The probe was tested on fixed, paraffin-embedded specimens, and an intense, specific hybridization signal was localized to the cytoplasm of hepatopancreatic epithelial cells that were infected with the NHP bacterium, as demonstrated by serial sections stained with hematoxylin and eosin or the Steiner and Steiner method. Negative results were obtained from normal shrimp and from shrimp infected with Vibrio spp. The specificity of the probe was confirmed using either mammalian or avian tissues infected with other intracellular bacteria, including Ehrlichia canis, Salmonella enteritidis, Brucella abortus, and Chlymidia spp., and using another species of shrimp (P. monodon) infected with a different rickettisa-like intracellular bacterium.

Animals↗