Glycocaulis profundi sp. nov., a marine bacterium isolated from seawater of the Mariana Trench.

A Gram-stain-negative, strictly aerobic, rod-shaped bacterium, without flagellum and designated ZYF765 ^T , was isolated from seawater sampled at a depth of 4000 m in the Mariana Trench. Strain ZYF765 ^T grew with 1-15 % (w/v) NaCl (optimum, 4 %), at 16-37 °C (28 °C) and at pH 6.0-10.0 (pH 7.0-8.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZYF765 ^T formed a lineage within the family Hyphomonadaceae , and was distinct from the most closely related species Glycocaulis abyssi , Glycocaulis albus and Glycocaulis alkaliphilus with 16S rRNA gene sequences similarities ranging from 98.42 to 98.63 %. The major respiratory quinone was ubiquinone-10 (Q-10). The polar lipids comprised three unidentified glycolipids, one unidentified aminophospholipid, one unidentified phospholipid and one unidentified aminolipid. The predominant fatty acids (more than 10 % of total fatty acids) were C _18 : 1 ω7 c (46.2 %) and C _18 : 0 (14.1 %). The DNA G+C content was 67.7 mol%. On the basis of the results of polyphasic taxonomic analysis, strain ZYF765 ^T is considered to represent a novel species within the genus Glycocaulis , for which the name Glycocaulis profundi sp. nov. is proposed. The type strain is ZYF765 ^T (=JCM 33028 ^T =MCCC 1K03554 ^T ).