Ruegeria mobilis sp. nov., a member of the Alphaproteobacteria isolated in Japan and Palau.

The taxonomic positions of two bacterial strains, MBIC01146(T) and MBIC01099, isolated from marine environments of Japan and Palau, respectively, were determined by using a polyphasic approach. The bacteria were aerobic, motile, Gram-negative rods and formed star-shaped aggregations. The G+C content of the genomic DNA ranged from 58.5 to 58.7 mol%. The major respiratory quinone was ubiquinone-10 and the predominant cellular fatty acids were C(16 : 0), C(18 : 1)omega6c and C(18 : 1)omega7c. 16S rRNA gene sequence analyses based on both neighbour-joining and maximum-parsimony methods revealed that strains MBIC01146(T) and MBIC01099 were positioned within the cluster comprising Ruegeria atlantica and Silicibacter lacuscaerulensis within subgroup alpha-3 of the Proteobacteria. The phenotypic and chemotaxonomic characteristics of the novel strains were similar to those of Ruegeria atlantica; however, DNA-DNA hybridization tests showed that the isolates represented an independent species. The isolates could be differentiated from Ruegeria atlantica based on several characteristics. Therefore, strains MBIC01146(T) and MBIC01099 are considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria mobilis sp. nov. is proposed. The type strain is MBIC01146(T) (=NBRC 101030(T)=CIP 109181(T)). An emended description of Ruegeria atlantica Uchino et al. 1999 is also given.