Pelagibacterium nitratireducens sp.nov., a marine Alphaproteobacterium isolated from the East China Sea.

A Gram-negative, rod-shaped, non-spore-forming aerobic bacterium, motile with a single polar flagellum, strain JLT2005(T), was isolated from surface seawater collected from the East China Sea and formed ivory white colonies on a rich organic medium. The strain was positive for catalase, oxidase, and urease. It grew in the presence of 0-12 % (w/v) NaCl (optimum 5 %), at 20-35 °C (optimum 25 °C), or at pH 6-10 (optimum pH 9). The major fatty acids (>10 %) were C(18:1)ω7c, C(19:0)ω8c cyclo, C(16:0), and C(18:0). The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and five unidentified glycolipids. Ubiquinone-10 and Ubiquinone-11 were present as the major quinones. The DNA G+C content was 74.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain JLT2005(T) belongs to the genus Pelagibacterium in the family Hyphomicrobiaceae, class Alphaproteobacteria. The closest neighbors were Pelagibacterium halotolerans B2(T) (98.7 % similarity) and Pelagibacterium luteolum 1_C16_27(T) (97.1 % similarity). DNA-DNA relatedness values of strain JLT2005(T) with P. halotolerans B2(T) and with P. luteolum 1_C16_27(T) were 31.6 and 25 %. Evidence from genotypic, chemotaxonomic, and phenotypic data shows that strain JLT2005(T) represents a novel species of the genus Pelagibacterium, for which the name Pelagibacterium nitratireducens sp. nov is proposed. The type strain is JLT2005(T) (=CGMCC 1.10829(T) =JCM 17767(T)).

Filomicrobium insigne sp. nov., isolated from an oil-polluted saline soil.

Strain SLG5B-19(T), isolated from an oil-polluted saline soil in Gudao in the coastal Shengli Oilfield, eastern China, was Gram-negative with monoprosthecae or bipolar prosthecae and buds on the prosthecal tips. Growth occurred at NaCl concentrations between 0 and 7 % (w/v), at temperatures between 4 and 45 degrees C, and at pH 6.0-9.0. Strain SLG5B-19(T) had Q-9 as the major respiratory quinone and unsaturated C(18 : 1)omega7c as the predominant cellular fatty acid. The G+C content of the genomic DNA was 59.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SLG5B-19(T) belonged to a clade with the genera Filomicrobium and Hyphomicrobium in the class Alphaproteobacteria. However, 16S rRNA gene sequence similarities of strain SLG5B-19(T) to the phylogenetically most closely related strains, i.e. the type strains of Filomicrobium fusiforme and Hyphomicrobium zavarzinii, were 95.8 and 94.5 %, respectively. In addition, the 16S rRNA gene sequence of strain SLG5B-19(T) had 24 signature nucleotides that were identical to those of the type strain of F. fusiforme. Based on phylogenetic analysis of 16S rRNA gene sequences, strain SLG5B-19(T) could be allocated to the genus Filomicrobium. However, distinct phenotypic differences were observed between strain SLG5B-19(T) and the type strain of F. fusiforme. It is therefore proposed that strain SLG5B-19(T) represents a novel species in the genus Filomicrobium, Filomicrobium insigne sp. nov. The type strain is SLG5B-19(T) (=CGMCC 1.6497(T)=LMG 23927(T)).

[Anoxygenic phototrophic bacteria of the high-altitude meromictic Lake Gek-Gel, Azerbaijan].

The anoxygenic phototrophic bacterial community of the high-altitude meromictic Lake Gek-Gel (Azerbaijan) was investigated in September 2003. The highest concentration of bacteriochlorophyll e (48 microg/l) was detected at a depth of 30 m; the peak of bacteriochlorophyll a (4.5 microg/l) occurred at 29 m. Phylogenetic analysis revealed that brown-colored green sulfur bacteria Chlorobium phaeobacteroides predominated in the lake. Nonsulfur purple bacteria phylogenetically close to Blastochloris sulfoviridis were found in insignificant amounts; these organisms have not been previously reported in Lake Gek-Gel.

Cucumibacter marinus gen. nov., sp. nov., a marine bacterium in the family Hyphomicrobiaceae.

A Gram-negative, rod-shaped, strictly aerobic micro-organism, designated strain CL-GR60(T), was isolated from coastal seawater from the East Sea, Korea. A 16S rRNA gene sequence analysis revealed a clear affiliation with the family Hyphomicrobiaceae. Phylogenetic analyses showed that strain CL-GR60(T) formed a robust cluster with the species of the genus Devosia at sequence similarity levels of 91.1-93.1 %; no other species in the family Hyphomicrobiaceae shared more than 90 % sequence similarity with strain CL-GR60(T). The strain grew optimally in the presence of 3-4 % sea salts at 30-35 degrees C and pH 7. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, two unidentified glycolipids, an unidentified phospholipid and an unidentified lipid. The strain contained C(18 : 1)omega7c (54.7 %), 11-methyl C(18 : 1)omega7c (19.3 %), C(18 : 0) (14.4 %) as the predominant fatty acids. Ubiquinone-10 was the major quinone. The DNA G+C content was 62.9 mol%. On the basis of physiological data, fatty acid composition and results of phylogenetic analysis of the 16S rRNA gene sequence, strain CL-GR60(T) represents a novel genus and species within the family Hyphomicrobiaceae, for which the name Cucumibacter marinus gen. nov., sp. nov. is proposed. The type strain of Cucumibacter marinus is CL-GR60(T) (=KCCM 90027(T) =DSM 18995(T)).