A Gram-stain-negative, strictly aerobic, non-motile, long, straight-rod and non-flagellated marine bacterium strain, designated SCR12T, was isolated from the gill of a shrimp collected in the Tangyin hydrothermal field of the Okinawa Trough. The growth temperature was in the range of 16-40 °C and the optimum temperature was 37 °C. Optimal growth occurred at pH 6.5 and in the presence of 3 % (w/v) NaCl. The predominant isoprenoid quinone of strain SCR12T was menaquinone-6 (MK-6). The predominant fatty acids (>10 %) were iso-C15 : 0 (44.2 %), iso-C15 : 1 G (19.0 %) and iso-C17 : 0 3-OH (12.1 %). The major polar lipids comprised one phosphatidylethanolamine, three unidentified phospholipids, two unidentified aminolipids and three unidentified lipids. Based on the results of 16S rRNA gene sequence analysis, strain SCR12T was found to be most closely related to Muricauda olearia CL-SS4T (98.09 %), followed by Muricauda beolgyonensis BB-My12T (97.65 %), Muricauda aquimarina SW-63T (97.58 %) and Muricauda ruestringensis DSM 13258T (97.31 %) and with lower sequence similarities (95.74-97.10 %) to other species of the genus Muricauda. Genome relatedness between strain SCR12T and M. olearia CL-SS4T was computed using both average nucleotide identity (ANI) and DNA-DNA hybridization (DDH) and resulted in values of 85.6 % and 29.3±2.3 %, respectively. The genomic DNA G+C content of strain SCR12T was 42.3 mol%. On the basis of polyphasic analysis, the strain SCR12T was considered to represent a novel species of the genus Muricauda, for which the name Muricauda alvinocaridis sp. nov. is proposed. The type strain is SCR12T (=MCCC 1K03731T=JCM 33425T).
Keywords: Muricauda alvinocaridis; Okinawa Trough; hydrothermal field; shrimp gill.