Spontaneous spheroplast formation by Desulfovibrio aestuarii

Youngiibacter fragilis gen. nov., sp. nov., isolated from natural gas production-water and reclassification of Acetivibrio multivorans as Youngiibacter multivorans comb. nov

A taxonomic study employing a polyphasic approach was performed on a novel anaerobic bacterium isolated from natural gas production-water. The bacterium stained Gram-negative and consisted of non-motile, non-spore-forming, rod-shaped cells. Products of glucose or starch fermentation were ethanol, CO2, formate, acetate and H2. The predominant fatty acids were C16 : 0 ALDE and summed feature 3 comprising C16 : 1ω7c and/or C16 : 1ω6c. The DNA G+C content was 45.5 mol%. 16S rRNA gene sequence analysis demonstrated that the nearest phylogenetic neighbours of the novel strain were Acetivibrio multivorans DSM 6139T (98.5 %) and Proteiniclasticum ruminis JCM 14817T (95.4 %). The DNA–DNA hybridization value between the novel organism and Acetivibrio multivorans PeC1 DSM 6139T was determined to be only 30.2 %, demonstrating the separateness of the two species. Based on phylogenetic, phenotypic and chemotaxonomic evidence that clearly distinguished strain 232.1T from Proteiniclasticum ruminis and other close relatives, it is proposed that the novel isolate be classified as representing a novel species of a new genus within the family Clostridiaceae , Youngiibacter fragilis gen. nov., sp. nov. The type strain of the type species is 232.1T ( = ATCC BAA-2257T = DSM 24749T). In addition, Acetivibrio multivorans is proposed to be reclassified as Youngiibacter multivorans comb. nov.

Comparison of the nucleic acids of helical and coccoid forms of Helicobacter pylori

The nucleic acids of the helical and coccoid forms of Helicobacter pylori were studied to determine if the coccoid forms are "viable (capable of growing) but nonculturable." Using a reference strain (NCTC 11638) and five clinical strains, the nucleic acid contents, DNA integrity, and results of PCR and reverse transcription-PCR (RT-PCR) were compared for helical H. pylori and coccoid forms induced using glycochenodeoxycholic acid or bismuth citrate. The DNA and RNA contents of the coccoid forms were respectively 6.8- and 8.1-fold lower than those of helical H. pylori after 3 days of induction and 11.5- and 14.7-fold lower after 7 days. Agarose gel electrophoresis of DNA extracted from the coccoid forms after 3 days of induction showed a smear pattern indicating DNA cleavage, whereas DNA from helical H. pylori showed a single band with a high molecular mass. After 12 days of induction, all RNA samples from 100% coccoid cultures were negative for the mRNA of urease A or the 26-kDa species-specific protein by RT-PCR. However, most RNA samples obtained after 3 or 7 days of induction were positive at low levels despite the lack of recovery from these cultures. These results suggest that the coccoid form of H. pylori has impaired genomic DNA and is in the process of cellular degeneration, thus being still alive but nonincreasable.

Isolation from haddock tissue of psychrophilic bacteria with maximum growth temperature below 20 degrees C

A series of seven gram-negative obligately psychrophilic cultures were isolated from a fresh haddock fillet and constituted 8.8% of the total bacterial population on the tissue. All of these isolates are facultatively anaerobic, ferment dextrose without gas production, produce trimethylamine, are sensitive to the vibriostatic agent 0/129, and grow at temperatures from 0 to 15 degrees C but not at 20 degrees C.

An ammonia-oxidizing bacterium, Nitrosovibrio tenuis nov. gen. nov. sp

An ammonia-oxidizing, autotroph growing, slender, curved rod was isolated from the soil of Hawaii. It is well distinguishable from any other nitrifying bacteria thus far described by their morphology. The cells are 1.1-3.0 mum long and 0.3-0.4 mum wide. They are motile by means of 1-4 subpolar to lateral flagella. In contrast to most of the ammonia-oxidizing bacteria the isolated vibrio is void of an extensive cytomembrane system. To categorize this not yet described species we propose to create the new genus Nitrosovibrio and to classify the isolated strain as Nitrosovibrio tenuis.

Biology of the chemoheterotrophic spirilla

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Morphology and round body fermation in Vibrio marinus

The morphology of Vibrio marinus MP-1 was studied by phase and electron microscopy. The ultrastructure of the vibrio form of V. marinus was found to be typically gram-negative with a trilaminar plasma membrane and cell wall. The coccoid or round bodies noted in otherwise pure cultures of V. marinus were frequently found in early and late stationary phase of growth. The round bodies in ultrathin section were found to contain at least one, and often three or four, cell units. Three types of round bodies were observed in ultrathin section, each differing in size and behavior: "spherules," "spheres" or the "round body," and "giant cells" or "macrospheres." The round bodies appeared to be associated with, or to result from, the constrictive cell division of V. marinus.