Salinisphaera japonica sp. nov., a moderately halophilic bacterium isolated from the surface of a deep-sea fish, Malacocottus gibber, and emended description of the genus Salinisphaera.

A moderately halophilic, slightly acidophilic, aerobic bacterium, designated strain YTM-1(T), was isolated from the body surface of Malacocottus gibber. Cells were Gram-stain-negative, short rods or cocci, approximately 0.9-1.1 µm long and 1.0-1.8 µm wide. Strain YTM-1(T) was able to grow with 1-30% NaCl (optimum, 7.5-10%, w/v), at 4-30 °C (optimum, 20-25 °C) and at pH 3.8-9.5 (optimum, pH 5.0-5.5). Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain YTM-1(T) belonged to the genus Salinisphaera with low similarity values to the type strains of recognized species of this genus (<94.8-94.4%). The polar lipids of strain YTM-1(T) consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, three unknown phospholipids and one unknown lipid. The predominant isoprenoid quinone was Q-8. The major fatty acids were C19:0ω8c cyclo, C18:1ω7c, C16:1ω5c and C16:0. The DNA G+C content of strain YTM-1(T) was 67.3 mol%. These phylogenetic, physiological and chemotaxonomic data indicated that strain YTM-1(T) represents a novel species of the genus Salinisphaera, for which the name Salinisphaera japonica sp. nov. is proposed. The type strain is YTM-1(T) (=JCM 18087(T)=CECT 8012(T)). An emended description of the genus Salinisphaera is also proposed.