Sinobacterium caligoides gen. nov., sp. nov., a new member of the family
Oceanospirillaceae
isolated from the South China Sea, and emended description of
Amphritea japonica
A taxonomic study was carried out on strain SCSWE24T, isolated from a seawater sample collected from the South China Sea. Cells of strain SCSWE24T were Gram-negative, rod-shaped, non-motile, moderately halophilic and capable of reducing nitrate to nitrite. Growth was observed at salinities from 1.5 to 4.5 % and at 4–37 °C; it was unable to degrade gelatin. The dominant fatty acids (>15 %) were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 50.4 %) and C16 : 0 (21.1 %). The G+C content of the chromosomal DNA was 58.8 mol%. 16S rRNA gene sequence comparisons showed that strain SCSWE24T was most closely related to an uncultured bacterium clone Tun3b.F5 (98 %; GenBank accession no. FJ169216), and showed 92 % similarity to an endosymbiont bacterium from the bone-eating worm Osedax mucofloris (clone Omu 9 c4791; FN773233). Levels of similarity between strain SCSWE24T and type strains of recognized species in the family Oceanospirillaceae were less than 93 %; the highest similarity was 92 %, to both Amphritea japonica JAMM 1866T and ‘Oceanicoccus sagamiensis’ PZ-5. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain SCSWE24T formed a distinct evolutionary lineage within the family Oceanospirillaceae . Strain SCSWE24T was distinguishable from members of phylogenetically related genera by differences in several phenotypic properties. On the basis of the phenotypic and phylogenetic data, strain SCSWE24T represents a novel species of a new genus, for which the name Sinobacterium caligoides gen. nov., sp. nov. is proposed. The type strain of Sinobacterium caligoides is SCSWE24T ( = CCTCC AB 209289T = LMG 25705T = MCCC 1F01088T). An emended description of Amphritea japonica is also provided.