Muricauda maritima sp. nov., Muricauda aequoris sp. nov. and Muricauda oceanensis sp. nov., three marine bacteria isolated from seawater.

Three Gram-stain-negative, non-motile, rod-shaped strains, designated 72T, NH166T and 40DY170T, were isolated from seawater samples of the West Pacific Ocean, South China Sea and West Pacific Ocean, respectively. The 16S rRNA gene sequence similarity results revealed that strains 72Tand NH166T were most closely related to Muricauda antarctica Ar-22T, Muricauda taeanensis JCM 17757T, Muricauda beolgyonensis KCTC 23501T, Muricauda lutimaris KCTC 22173T and Muricauda hadalis MT-229T with 97.2-98.0% sequence similarity. 16S rRNA gene sequence analysis also indicated that strain 40DY170T was most closely related to Muricauda ruestringensis DSM 13258T, Muricauda aquimarina JCM 11811T, Muricauda lutimaris KCTC 22173T and Muricauda oceani 501str8T with 97.6-98.1% sequence similarity. The 16S rRNA gene sequence similarity values among strains 72T, NH166T and 40DY170T were 96.5-99.2%. Phylogenetic analyses indicated that three new isolates represented three novel species by forming two distinctive lineages within the genus Muricauda. The DNA G+C contents of strain 72T, NH166T and 40DY170T were 43.4, 43.4 and 42.4 mol%, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values between strains 72T, NH166T, 40DY170T and the reference strains were 76.5-93.5% and 19.2-53.5%, respectively. The sole respiratory quinone in all strains was menaquinone-6. Their major fatty acids were iso-C17:0 3-OH, iso-C15:0 and iso-C15 : 1 G. The major polar lipids of strains 72T and NH166T were phosphatidylethanolamine, one unidentified aminolipid and two unidentified lipids. The major polar lipids of strain 40DY170T were phosphatidylglycerol, one unidentified phospholipid, one unidentified aminolipid and two unidentified lipids. On the basis of their distinct taxonomic characteristics, the three isolates represent three novel species of the genus Muricauda, for which the names Muricauda maritima sp. nov. (type strain 72T=KCTC 62229T=MCCC 1K03350T), Muricauda aequoris sp. nov. (NH166T=KCTC 62228T=MCCC 1K03449T) and Muricauda oceanensis sp. nov. (40DY170T=KCTC 72200T=MCCC 1K03569T) are proposed.