| Abstract |
A taxonomic study was carried out on strain 22II-S10s(T), which was isolated from the surface seawater of the Atlantic Ocean. The bacterium was found to be Gram-negative, oxidase and catalase positive, rod shaped and motile by subpolar flagella. The isolate was capable of gelatine hydrolysis but unable to reduce nitrate to nitrite or degrade Tween 80 or aesculin. Growth was observed at salinities of 0.5-18 % (optimum, 2-12 %), at pH of 3-10 (optimum, 7) and at temperatures of 10-41 °C (optimum 28 °C). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 22II-S10s(T) belongs to the genus Roseivivax, with highest sequence similarity to Roseivivax halodurans JCM 10272(T) (97.2 %), followed by Roseivivax isoporae LMG 25204(T) (97.0 %); other species of genus Roseivivax shared 95.2-96.7 % sequence similarity. The DNA-DNA hybridization estimate values between strain 22II-S10s(T) and the two type strains (R. halodurans JCM 10272(T) and R. isoporae LMG 25204(T)) were 22.00 and 21.40 %. The principal fatty acids were identified as Summed Feature 8 (C18:1 ω7c/ω6c) (67.4 %), C18:0 (7.2 %), C19:0 cyclo ω8c (7.1 %), C18:1 ω7c 11-methyl (6.8 %) and C16:0 (5.9 %). The respiratory quinone was determined to be Q-10 (100 %). Phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an aminolipid, a glycolipid and three phospholipids were present. The G+C content of the chromosomal DNA was determined to be 67.5 mol%. The combined genotypic and phenotypic data show that strain 22II-S10s(T) represents a novel species within the genus Roseivivax, for which the name Roseivivax atlanticus sp. nov. is proposed, with the type strain 22II-S10s(T) (= MCCC 1A09150(T) = LMG 27156(T)).
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