Amphritea opalescens sp. nov., isolated from sediment adjacent to Fildes Peninsula, Antarctica

Abstract

A taxonomic study was carried out on a Gram-stain-negative bacterium, namely strain ANRC-JH13T, isolated from a sediment sample collected at Jasper beach, adjacent to Fildes Peninsula, Antarctica. Cells of strain ANRC-JH13T were non-spore-forming rods and motile by the way of flagellum. Strain ANRC-JH13T was facultatively anaerobic, oxidase-positive, and catalase-positive. Growth of strain ANRC-JH13T occurred at 10-42 °C (optimum, 28 °C), pH 4.0-11.0 (pH 7.0) and 0-12.0 % (w/v) NaCl (1.0-2.0 %). Its predominant fatty acids were C16 : 0 (21.7 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 38.3 %), and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 20.1 %). Isoprenoid quinone Q-8 was the major respiratory quinone. Its major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids, and four unknown polar lipids. The DNA G+C content was 48 mol%. Strain ANRC-JH13T showed the highest 16S rRNA gene sequence similarity to Amphritea balenae JAMM 1525T (97.9 %), followed by Amphritea atlantica M41T (97.8 %) and Amphritea japonica JAMM 1866T (97.3 %), and formed a lineage within the genus Amphritea on the phylogenetic trees. However, the in silico average nucleotide identity values between strain ANRC-JH13T and A. balenae JAMM 1525T, A. atlantica M41T, and A. japonica JAMM 1866T were 74.0, 76.7, and 74.9 %, respectively. The in silico DNA-DNA hybridization values between them were 19.8, 20.6, and 19.4 %, respectively. Based on the results from phenotypic, chemotaxonomic, and phylogenetic analyses, strain ANRC-JH13T is considered to represent a novel species of the genus Amphritea, for which the name Amphriteaopalescens sp. nov. is proposed. The type strain is ANRC-JH13T (=MCCC 1K03512T=KCTC 62532T).