Muricauda antarctica sp. nov., a marine member of the Flavobacteriaceae isolated from Antarctic seawater.

A Gram-stain-negative, rod-shaped bacterium with appendages, designated Ar-22T, was isolated from a seawater sample collected from the western part of Prydz Bay, near Cape Darnley, Antarctica. Strain Ar-22T grew optimally at 35 °C, at pH 7.5 and in the presence of 1–3 % (w/v) NaCl. The isolate was positive for casein, gelatin and Tween 20 decomposition and negative for H2S production and indole formation. Chemotaxonomic analysis showed that MK-6 was the major isoprenoid quinone and phosphatidylethanolamine was the major polar lipid. The major fatty acids were iso-C17 : 0 3-OH, iso-C15 : 1 G, iso-C15 : 0 and C16 : 1ω7c/iso-C15 : 0 2OH. The genomic DNA G+C content was 44.8 mol%. Comparative 16S rRNA gene sequence analysis revealed that strain Ar-22T is closely related to members of the genus Muricauda , sharing 94.2–97.3 % sequence similarity with the type strains of species of the genus Muricauda and being most closely related to the Muricauda aquimarina . Phylogenetic analysis based on the 16S rRNA gene sequence comparison confirmed that strain Ar-22T formed a deep lineage with Muricauda flavescens . Sequence similarity between strain Ar-22T and Muricauda ruestringensis DSM 13258T, the type species of the genus Muricauda , was 96.9 %. Strain Ar-22T exhibited mean DNA–DNA relatedness values of 40.1 %, 49.4 % and 25.7 % to M. aquimarina JCM 11811T, M. flavescens JCM 11812T and Muricauda lutimaris KCTC 22173T, respectively. On the basis of phenotypic and genotypic data, strain Ar-22T represents a novel species of the genus Muricauda , for which the name Muricauda antarctica sp. nov. (type strain Ar-22T = CGMCC 1.12174T = JCM 18450T) is proposed.