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At least 415 records · Page 23Linked to original sources
PubMed2007

Evidence for chemoautotrophic symbiosis in a Mediterranean cold seep clam (Bivalvia: Lucinidae): comparative sequence analysis of bacterial 16S rRNA, APS reductase and RubisCO genes.

Symbioses between lucinid clams (Bivalvia: Lucinidae) and autotrophic sulphide-oxidizing bacteria have mainly been studied in shallow coastal species, and information regarding deep-sea species is scarce. Here we study the symbiosis of a clam, resembling Lucinoma kazani, which was recently collected in sediment cores from new cold-seep sites in the vicinity of the Nile deep-sea fan, eastern Mediterranean, at depths ranging from 507 to 1691 m. A dominant bacterial phylotype, related to the sulphide-oxidizing symbiont of Lucinoma aequizonata, was identified in gill tissue by comparative 16S rRNA gene sequence analysis. A second phylotype, related to spirochete sequences, was identified twice in a library of 94 clones. Comparative analyses of gene sequences encoding the APS reductase alpha subunit and ribulose-1,5-bisphosphate carboxylase oxygenase support the hypothesis that the dominant symbiont can perform sulphide oxidation and autotrophy. Transmission electron micrographs of gills confirmed the dominance of sulphide-oxidizing bacteria, which display typical vacuoles, and delta(13)C values measured in gill and foot tissue further support the hypothesis for a chemoautotrophic-sourced host carbon nutrition.

Animals↗
PubMed1995

A monoclonal antibody reacting with the cell envelope of spirochaetes isolated from cases of intestinal spirochaetosis in pigs and humans.

A monoclonal antibody (mAb) designed BJL/AC1 was prepared against the cell envelope of an intestinal spirochaete (strain 3295) that was isolated from a pig with intestinal spirochaetosis. The mAb reacted with a band of approximately 29 kDa in cell envelope preparations from 13 porcine and 11 human spirochaetes isolated from cases of intestinal spirochaetosis, but did not react with preparations made from a range of other intestinal spirochaetes. Immunogold labelling demonstrated that the reactive epitope was located on the cell envelope of the strains causing intestinal spirochaetosis. The mAb was used in an indirect immunofluorescence test to detect spirochaetes in the faeces of pigs with experimentally induced intestinal spirochaetosis. The mAb should prove to be a useful reagent for detection and identification of spirochaetes that are specifically associated with intestinal spirochaetosis.

Animals↗
PubMed1987

Susceptibility of small-sized oral spirochetes to eight antibiotics and chlorhexidine.

The purpose of the study was to examine the susceptibility of two different small-sized spirochete morphotypes from subgingival plaque to eight antibiotics and chlorhexidine. MIC-values were determined by a broth dilution method and related to achievable antibiotic tissue- and blood concentrations. The spirochetes were characterized as susceptible, moderate susceptible, and resistant to the different antibiotics. The MICs of tetracycline hydrochloride, doxycycline, penicillin G, and chlorhexidine were all considerably lower for spirochete strains with a 2:4:2 endoflagella system (two endoflagella from each cell-end) than for strains with a 1:2:1 endoflagella system (one endoflagellum from each cell-end). No differences were observed for the remaining antibiotics. Spirochetes containing one endoflagellum from each cell-end were found to be susceptible to metronidazole and doxycycline, susceptible to moderate susceptible to tetracycline hydrochloride, moderate susceptible to penicillin G, and resistant to the remaining antibiotics. Spirochetes containing two endoflagella from each cell-end were susceptible to doxycycline, tetracycline hydrochloride, and metronidazole. Susceptible to moderate susceptible to penicillin G. These spirochetes were resistant to the remaining agents. The significance of these observations is discussed in relation to obtainable gingival crevicular fluid concentrations and treatment of marginal periodontitis.

Anti-Bacterial Agents↗
PubMed1982

Physiological diversity of rumen spirochetes.

Bovine rumen fluid contained relatively large numbers of spirochetes capable of fermenting polymers commonly present in plant materials. Polymers such as xylan, pectin, and arabinogalactan served as fermentable substrates for the spirochetes, whereas cellulose did not. Furthermore, spirochetes cultured from rumen fluid utilized as growth substrates hydrolysis products of plant polymers (e.g., D-xylose, L-arabinose, D-galacturonic acid, D-glucuronic acid, cellobiose), but did not ferment amino acids. Viable cell counts of spirochetes capable of fermenting individual plant polymers or their hydrolysis products yielded minimum values ranging from 0.2 X 10(6) to 4 X 10(6) cells per ml of rumen fluid. Thirteen strains of rumen spirochetes were characterized in terms of their fermentation products from glucose, the guanine plus cytosine content of their DNA, their ultrastructure, and their ability to ferment pectin, starch, or arabinogalactan. Of the 13 strains, 6 fermented glucose mainly to formate, acetate, and succinate, whereas the remaining 7 strains did not produce succinate, but instead formed ethanol, in addition to formate and acetate. The succinate-forming strains had two periplasmic (axial) fibrils per cell, measured 0.2 to 0.3 by 5 to 8 micrograms, had a guanine plus cytosine content of the DNA ranging from 36 to 38 mol%, and lacked the ability to ferment pectin, starch, or arabinogalactan. The ethanol-forming strains had from 8 to more than 32 periplasmic fibrils per cell, tended to be larger in cell size than the succinate-forming strains, and had a guanine plus cytosine content of the DNA ranging from 41 to 54 mol%. Some of the ethanol-forming strains fermented pectin, starch, or arabinogalactan. The results of this study indicate that the bovine rumen is inhabited by a physiologically and morphologically diverse population of spirochetes. It is likely that these spirochetes contribute significantly to the degradation of plant materials ingested by the ruminants.

Animals↗
PubMed2001

Characterization of a novel spirochete associated with the hydrothermal vent polychaete annelid, Alvinella pompejana.

A highly integrated, morphologically diverse bacterial community is associated with the dorsal surface of Alvinella pompejana, a polychaetous annelid that inhabits active high-temperature deep-sea hydrothermal vent sites along the East Pacific Rise (EPR). Analysis of a previously prepared bacterial 16S ribosomal DNA (rDNA) library identified a spirochete most closely related to an endosymbiont of the oligochete Olavius loisae. This spirochete phylotype (spirochete A) comprised only 2.2% of the 16S rDNA clone library but appeared to be much more dominant when the same sample was analyzed by denaturing gradient gel electrophoresis (DGGE) and the terminal restriction fragment length polymorphism procedure (12 to 18%). PCR amplification of the community with spirochete-specific primers used in conjunction with DGGE analysis identified two spirochete phylotypes. The first spirochete was identical to spirochete A but was present in only one A. pompejana specimen. The second spirochete (spirochete B) was 84.5% similar to spirochete A and, more interestingly, was present in the epibiont communities of all of the A. pompejana specimens sampled throughout the geographic range of the worm (13 degrees N to 32 degrees S along the EPR). The sequence variation of the spirochete B phylotype was less than 3% for the range of A. pompejana specimens tested, suggesting that a single spirochete species was present in the A. pompejana epibiotic community. Additional analysis of the environments surrounding the worm revealed that spirochetes are a ubiquitous component of high-temperature vents and may play an important role in this unique ecosystem.

Animals↗
PubMed1974

Oxygen uptake by Treponema pallidum.

Virulent Treponema pallidum has been shown to consume O(2) at a rate similar to that of the known aerobic spirochaete, Leptospira. Such O(2) uptake is cyanide sensitive, indicating a functioning cytochrome oxidase. Inhibition of O(2) uptake by azide, chlorpromazine, and amytal further suggests a functioning electron transport system for the oxidation of nicotinamide adenine dinucleotide (reduced) to O(2). Evidence is consistent with the probability that this terminal electron-transport system is coupled to oxidative phosphorylation. The potential significance of these findings is discussed.

Amobarbital↗
PubMed1975

Synergism between Trichuris suis and the microbial flora of the large intestine causing dysentery in pigs.

The role of the microbial flora of the large intestine in experimental Trichuris suis infection was studied by comparing the clinical syndrome in conventionally reared (CR) pigs, specific pathogen-free pigs, and gnotobiotic pigs. Thedisease in CR pigs was characterized by a severe mucohemorrhagic enteritis; in contrast, a mild catarrhal enteritis was observed in specific pathogen-free and gnotobiotic pigs. Spirochaetes and vibrio-like organisms were observed only in CR pigs and increased during the clinical phase of the disease. The clinical syndrome was not transmitted by oral administration of intestinal or fecal material from infected CR pigs to CR pigs free of T. suis. Smaller numbers of T. suis produced diarrhea in CR pigs and significantly reduced the growth rates of infected animals; clinical signs and the reduction in growth rate was prevented by incorporating an antibacterial substance (dimetridazole) in the food. Although clinical trichuriasis closely resembles swin dysentery, the two syndromes seem to be distinct. The present results suggest that a microbial component acts synergistically with T. suis to produce the severe clinical syndrome in CR pigs, but identification of the microbial component and the mechanism by which clinical signs are produced await further studies of the bacterial flora of the large intestine of pigs.

Animals↗
PubMed1972

Ultrastructural identification of spirochetes and flagellated microbes at the brush border of the large intestinal epithelium of the rhesus monkey.

Spiral-shaped organisms exclusively and intimately populate the brush border of the cecal and colonic epithelium of healthy monkeys (Macaca mulatta). These organisms replace the glycocalyx, destroy most microvilli, and attenuate the terminal web of the brush border. Despite these remarkable alterations, the remaining host cellular structure is unchanged. Two structurally distinct microbes, a spirochete and a flagellate, were recognized by electron microscopy. These spirochetes share the general characteristics of other known spirochetes: they are 3 to 6 mum long and 0.2 to 0.4 mum wide, spiral 2 to 6 times, and have axial fibrils of 6-12-6 and 4-8-4 arrangements. Flagellated microbes are 4 to 6 mum long and 0.2 to 0.4 mum wide, spiral 2 to 4 times, and are characterized by a polar flagellum which originates from the terminal button at each end of the cytoplasmic body. This in vivo ultrastructural study of anaerobic spiral-shaped organisms bypasses the difficulties of in vitro culture techniques and provides a detailed description and identification of these organisms in their host environment.

Animals↗
PubMed1995

Identification of a new intestinal spirochete with pathogenicity for chickens.

Two intestinal spirochete isolates obtained from chickens with diarrhea were examined by electron microscopy, biochemical tests, rRNA gene restriction pattern analysis, and multilocus enzyme electrophoresis. One isolate (strain 91-1207/C1) was pathogenicity tested in vivo in chickens. The chicken spirochetes were morphologically indistinguishable from Serpulina innocens and Serpulina hyodysenteriae and phenotypically similar to S. innocens. However, the chicken spirochetes could be distinguished from S. innocens, S. hyodysenteriae, and other swine intestinal spirochetes by rRNA gene restriction pattern analysis and multilocus enzyme electrophoresis. In pathogenicity tests in 1-day-old chicks and 14-month-old hens, chicken spirochete 91-1207/C1 produced pale-yellow, watery cecal contents and mild lymphocytic typhlitis. These findings support the conclusion that avian intestinal spirochetes can be pathogenic to commercial poultry and that the microorganisms are different from intestinal spirochetes that infect pigs.

Animals↗
PubMed1973

Localization of bacteria in the gastrointestinal tract: a possible explanation of intestinal spirochaetosis.

The large intestine of rats and dogs was examined by light and electron microscopy. In both species localization of bacteria in specific areas of the tissue was observed. Fusiform bacteria mixed with spirochaetes were seen at the opening of the crypts into the large bowel. However, at the base of the crypts homogeneous populations of spiral organisms were found; some crypts contained Borrelia-type spirochaetes, whereas others contained spiral bacteria with other morphology. Very few spiral bacteria, including those of the spirillum type, were seen in the lumen of the large intestine. Experiments in rats showed that mucosa-associated spiral organisms appeared in large numbers in the stools when diarrhea was induced with magnesium sulfate. These observations were taken as a basis for explaining intestinal spirochaetosis of dogs and other animals, a syndrome which has been frequently described and which, until now, has been considered to reflect pathogenicity of these organisms.

Animals↗