Flavivirga rizhaonensis sp. nov., a marine bacterium isolated from intertidal sand

Flavivirga spongiicola sp. nov. and Flavivirga abyssicola sp. nov., Isolated from Marine Environments

Two novel Gram-stain-negative, strictly-aerobic, rod-shaped (1.2 ± 3.4 μm × 0.3 ± 0.7 μm), and non-motile marine bacterial species, designated MEBiC05379T and MEBiC07777T, were isolated from a marine sponge Pseudaxinella sp. in Gangneung City and deep-sea sediments of the Ulleung basin in the East Sea of Korea, respectively. The 16S rRNA gene sequence analysis revealed high levels of similarities between these strains and members of the genus Flavivirga (97.0-98.4% sequence identities). Both novel strains revealed as mesophilic, neutrophilic in pH and slightly halophilic. Similar to those of other Flavivirga members, the primary cellular fatty acids of both strains were iso-C15:0, iso-C15:1 G, iso-C15:03-OH, and iso-C17:0 3-OH, with MEBiC05379T and MEBiC07777T containing relatively higher proportions of C12:0 and summed feature 3 (C16:1ω7c and/or C16:1ω6c). In both taxa, the major isoprenoid quinone was MK-6. The DNA G + C contents of MEBiC05379T and MEBiC07777T genomes were 32.62 and 32.46 mol%, respectively. Compared to other members of Flavivirga, both strains exhibited similar DNA G + C ratio and fatty acids pattern, yet enzyme expression and carbon sources utilization pattern were different. Genomes of the genus Flavivirga showed enzyme preferences to fucoidan and sulfated galactans. Considering the monophyly rule, AAI values delineate the genus Flavivirga from adjacent genera calculated to be 76.0-78.7%. Based on the phenotypic, genomic and biochemical data, strains for MEBiC05379T and MEBiC07777T thus represent two novel species in the genus Flavivirga, for which the names Flavivirga spongiicola sp. nov. (MEBiC05379T [= KCTC 92527 T = JCM 16662 T]), and Flavivirga abyssicola sp. nov. (MEBiC07777T [= KCTC 92563 T = JCM 36477 T]) are proposed.

Palleronia sediminis sp. nov. and Flavivirga algicola sp. nov., two marine bacteria isolated from offshore areas near Weihai

Two bacterial strains, designated SS33^T and Y03^T, were isolated from marine sediment and marine red alga collected on the coast of Weihai, PR China. Based on the results of 16S rRNA gene sequence analysis, strain SS33^T was found to be closely related to Primorskyibacter marinus PX7^T, Pelagivirga dicentrarchi YLY04^T, Palleronia marisminoris DSM 26347^T and Maribius pontilimi GH1-23^T with 94.8, 94.6, 94.5 and 94.5 % sequence similarity; strain Y03^T was found to be closest to Flavivirga aquimarina EC2D5^T, Flavivirga eckloniae ECD14^T and Flavivirga amylovorans JC2681^T with 96.4, 96.1 and 96.0 % sequence similarity. Strain SS33^T grew at 4-37 °C (optimum, 33 °C), at pH 6.0-9.5 (optimum, pH 7.5-8.0) and in the presence of 0-10 % (w/v) NaCl (optimum, 3.0 %). Chemotaxonomic analysis of strain SS33^T showed that the predominant respiratory quinone was ubiquinone-10. The major fatty acids (>10.0 %) included C_18 : 1  ω7c and C_16 : 0. The major polar lipids included phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid, one unidentified glycolipid, one unidentified polar lipid and two unidentified aminolipids. Strain Y03^T grew at 15-40 °C (optimum, 28 °C), at pH 6.5-8.0 (optimum, pH 7.0) and in the presence of 0.5-9.0 % (w/v) NaCl (optimum, 2.0%). Chemotaxonomic analysis showed that the predominant respiratory quinone was menaquinone-6. The major fatty acids (>10.0 %) included iso-C_15 : 0, iso-C_15 : 1 G, iso-C_17 : 0 3-OH and iso-C_15 : 0 3-OH. The major polar lipids included phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid and four unidentified polar lipids. Based on the polyphasic data, strain SS33^T is considered to represent a novel species of the genus Palleronia, for which the name Palleronia sediminis sp. nov. is proposed, with the type strain SS33^T (=KCTC 62986^T=MCCC 1H00387^T). Strain Y03^T is considered to represent a novel species of the genus Flavivirga, for which the name Flavivirga algicola sp. nov. is proposed, with the type strain Y03^T (=KCTC 72001^T=MCCC 1H00386^T).

Phylogenomic Analyses of a Clade Within the Family Flavobacteriaceae Suggest Taxonomic Reassignments of Species of the Genera Algibacter, Hyunsoonleella, Jejuia, and Flavivirga, and the Proposal of Pseudalgibacter gen. nov. and Pseudalgibacter alginicilyticus comb. nov

The family Flavobacteriaceae forms a major branch within the phylum Bacteroidetes. Whole-genome sequence-based analysis could significantly improve the accuracy of taxonomic assignments. In this study, phylogenomic analyses were carried out to revisit the taxonomic status of a clade of the family Flavobacteriaceae. Taking genome-based phylogeny as the primary guideline and average amino acid identity and phenotypic information as supplements, the following taxonomic proposals were put forward: Arenitalea lutea should be reclassified into the genus Algibacter; Algibacter aquaticus should be reclassified into the genus Flavivirga; Jejuia pallidilutea and Algibacter aestuarii should be reclassified into the genus Hyunsoonleella; Algibacter alginicilyticus should be reclassified into the novel genus Pseudalgibacter gen. nov. This study builds up a solid framework for taxonomic decisions of a clade of the family Flavobacteriaceae and will contribute to further insights into the evolution of this family.

Maribacter luteus sp. nov., a marine bacterium isolated from intertidal sand of the Yellow Sea

A novel rod-shaped and Gram-stain-negative bacterium, designated strain RZ05^T, was isolated from a sand sample collected from the intertidal zone of the Yellow Sea, PR China. Results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain RZ05^T clusters within the genus Maribacter, a member of the family Flavobacteriaceae, and has the highest sequence similarity to Maribacter polysiphoniae KCTC 22021^T (97.8 %), followed by Maribacter arenosus KCTC 52191^T (97.2 %). Cells of this strain were observed to be aerobic, oxidase- and catalase-positive, motile by gliding and formed yellow colonies. Growth occurred at 7-40 °C (optimum, 30 °C), at pH 6.5-9.5 (optimum, pH 7.0) and with 0.5-6 % (optimum, 2 %) NaCl. Its polar lipid profile included phosphatidylethanolamine, two unidentified glycolipids, one unidentified aminolipid and four unidentified lipids. The major cellular fatty acids were iso-C_15 : 0, iso-C_15 : 1 G, iso-C_17 : 0 3-OH, iso-C_16 : 0 3-OH, iso-C_15 : 0 3-OH, summed feature 9 (10-methyl C_16 : 0/iso-C_17 : 1  ω9c) and summed feature 3 (iso-C_15 : 0 2-OH/C_16 : 1  ω7c/C_16 : 1  ω6c). The only respiratory quinone was menaquinone 6 (MK-6). The genome of strain RZ05^T was 4.65 Mbp with a G+C content of 38.9 mol%. The average nucleotide identity and in silico DNA-DNA hybridization values between strain RZ05^T and its most closely related type strain M. polysiphoniae KCTC 22021^T were 80.3 and 26.3  %, respectively. The results of phylogenetic, phenotypic and chemotaxonomic analyses indicated that strain RZ05^T represents a novel species of the genus Maribacter, for which the name Maribacter luteus sp. nov. is proposed. The type strain is RZ05^T (=KCTC 62834^T=MCCC 1K03617^T).