Marinicauda pacifica gen. nov., sp. nov., a prosthecate alphaproteobacterium of the family Hyphomonadaceae isolated from deep seawater

Abstract

A marine prosthecate bacterium, designated strain P-1 km-3(T), was isolated from deep seawater from the Pacific. Cells of strain P-1 km-3(T) were Gram-stain-negative, aerobic, catalase- and oxidase-positive, dimorphic rods with a single polar prostheca or flagellum. The strain hydrolysed gelatin and grew at 6-40 °C (optimum, 30 °C) and with 0.5-12% (w/v) NaCl (optimum, 2%). Phylogenetic analysis of the 16S rRNA gene sequences revealed that strain P-1 km-3(T) belonged to the family Hyphomonadaceae in the class Alphaproteobacteria and represented a separate lineage, located between the genera Oceanicaulis and Woodsholea. Sequence similarities of strain P-1 km-3(T) with type strains of species of the genera Oceanicaulis and Woodsholea were 93.2-93.9%. The predominant cellular fatty acids in strain P-1 km-3(T) were C18:1ω7c, C18:0, 11-methyl C18:1ω7c, C17:0 and C19:0 cyclo ω8c. The major respiratory quinone of strain P-1 km-3(T) was Q-10. The polar lipids of strain P-1 km-3(T) comprised glucuronopyranosyldiglyceride (GUDG), monoglycosyldiglyceride (MGDG), sulfo-quinovosyl diacylglycerol (SQDG), phosphatidylglycerol (PG), an unidentified phospholipid (PL) and an unidentified lipid (L). The genomic DNA G+C content of strain P-1 km-3(T) was 66.0 mol%. On the basis of the polyphasic data presented in this study, strain P-1 km-3(T) is proposed to represent a novel species in a new genus, Marinicauda pacifica gen. nov., sp. nov., within the family Hyphomonadaceae. The type strain of the type species is P-1 km-3(T) (=KACC 16526(T)=CGMCC 1.11031(T)).