Draft Genome Sequence of Methylovulum psychrotolerans Sph1 T , an Obligate Methanotroph from Low-Temperature Environments

ABSTRACT Methylovulum psychrotolerans Sph1 T is an aerobic, obligate methanotroph, which was isolated from cold methane seeps in West Siberia. This bacterium possesses only a particulate methane monooxygenase and is widely distributed in low-temperature environments. Strain Sph1 T has the genomic potential for biosynthesis of hopanoids required for the maintenance of intracytoplasmic membranes.

Halochromatium roseum sp. nov., a non-motile phototrophic gammaproteobacterium with gas vesicles, and emended description of the genus Halochromatium

A rod-shaped, marine, phototrophic, purple sulfur bacterium containing gas vesicles was isolated from a marine solar saltern at Kakinada, India. Cells of strain JA134T are Gram-negative, non-motile rods, with vesicular intracytoplasmic membranes, and the strain has an absolute requirement for NaCl for growth. Bacteriochlorophyll a and the carotenoid okenone are present as photosynthetic pigments. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA134T clusters with members of the genus Halochromatium, but is distinctly separated from the species reported so far. The morphological and physiological differences of strain JA134T from other Halochromatium species support the description of strain JA134T (=ATCC BAA-1363T =DSM 18859T =JCM 14151T) as the type strain of a novel species, Halochromatium roseum sp. nov.

Methylosoma difficile gen. nov., sp. nov., a novel methanotroph enriched by gradient cultivation from littoral sediment of Lake Constance

A novel methanotroph, strain LC 2T, was isolated from the littoral sediment of Lake Constance by enrichment in opposing gradients of methane and oxygen, followed by traditional isolation methods. Strain LC 2T grows on methane or methanol as its sole carbon and energy source. It is a Gram-negative, non-motile, pale-pink-coloured methanotroph showing typical intracytoplasmic membranes arranged in stacks. Cells are coccoid, elliptical or rod-shaped and occur often in pairs. Strain LC 2T grows at low oxygen concentrations and in counter-gradients of methane and oxygen. It can grow on medium free of bound nitrogen, possesses the nifH gene and fixes atmospheric nitrogen at low oxygen pressure. It grows at neutral pH and at temperatures between 10 and 30 °C. Phylogenetically, it is most closely related to the genus Methylobacter, with the type strains of Methylobacter tundripaludum and Methylobacter psychrophilus showing 94 and 93.4 % 16S rRNA gene sequence similarity, respectively. Furthermore, the pmoA gene sequence of strain LC 2T is most closely related to pmoA gene sequences of Methylobacter strains (92 % similar to Methylobacter sp. LW 12 by deduced amino acid sequence identity). The DNA G+C content is 49.9 mol% and the major cellular fatty acid is 16 : 1ω7c (60 %). Strain LC 2T (=JCM 14076T=DSM 18750T) is described as the type strain of a novel species within a new genus, Methylosoma difficile gen. nov., sp. nov.

Rhodovulum marinum sp. nov., a novel phototrophic purple non-sulfur alphaproteobacterium from marine tides of Visakhapatnam, India

A yellowish-brown bacterium was isolated from enrichment cultures inoculated with seawater samples from the eastern coast of India (Visakhapatnam) under photoheterotrophic conditions. Enrichment and isolation in a medium containing 2 % NaCl (w/v) yielded strain JA128T, which has ovoid to rod-shaped cells, also forms chains and is non-motile. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA128T clusters with the Alphaproteobacteria and the sequence similarity with its closest relatives, Rhodovulum iodosum and Rhodovulum sulfidophilum, was 95 %. Strain JA128T contained vesicular intracytoplasmic membranes, bacteriochlorophyll a and carotenoids of the spheroidene series. Strain JA128T was mesophilic, slightly acidophilic, slightly halophilic and grew photoheterotrophically with a number of organic compounds as carbon source and electron donor. It was unable to grow photoautotrophically, chemoautotrophically or by fermentative modes. It did not utilize sulfide, thiosulfate or hydrogen as electron donors. Thiamine was required as a growth factor. Based on the 16S rRNA gene sequence analysis, morphological and physiological characteristics, strain JA128T was significantly different from other species of the genus Rhodovulum and was recognized as a novel species for which the name Rhodovulum marinum sp. nov. is proposed. The type strain is JA128T (=ATCC BAA 1215T=CCUG 52183T=JCM 13300T).