Comparative genomic analysis of the genus Marinomonas and taxonomic study of Marinomonas algarum sp. nov., isolated from red algae Gelidium amansii

Members of the genus Marinomonas are known for their environmental adaptation and metabolically versatility, with abundant proteins associated with antifreeze, osmotic pressure resistance, carbohydrase and multiple secondary metabolites. Comparative genomic analysis focusing on secondary metabolites and orthologue proteins was conducted with 30 reference genome sequences in the genus Marinomonas. In this study, a Gram-stain-negative, rod-shaped, non-flagellated and strictly aerobic bacterium, designated as strain E8^T, was isolated from the red algae (Gelidium amansii) in the coastal of Weihai, China. Optimal growth of the strain E8^T was observed at temperatures 25-30 °C, pH 6.5-8.0 and 1-3% (w/v) NaCl. The DNA G + C content was 42.8 mol%. The predominant isoprenoid quinone was Q-8 and the major fatty acids were C_16:0, summed feature 3 and summed feature 8. The major polar lipids were phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). Based on data obtained from this polyphasic taxonomic study, strain E8^T should be considered as a novel species of the genus Marinomonas, for which the name Marinomonas algarum is proposed. The type strain is E8^T (= KCTC 92201^T = MCCC 1K07070^T).

Maribrevibacterium harenarium gen. nov., sp. nov., represented by a marine strain of the family Oceanospirillaceae

A Gram-stain-negative, non-motile, facultatively anaerobic, short rod-shaped bacterium, designated HB171799^T, was isolated from seacoast sandy soil collected at Qishui Bay, Hainan, PR China. The chemotaxonomic analysis revealed that the respiratory quinones were Q-8 and Q-7, and the major cellular fatty acids were summed feature 8 (comprising C_18 : 1  ω7c and/or C_18 : 1  ω6c), C_16 : 0 and C_18 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid and an unidentified lipid. The size of the draft genome was 3.68 Mb with a DNA G+C content of 48.0 mol%. Results of phylogenetic analyses based on 16S rRNA gene and genome sequences showed that the novel isolate belonged to the family Oceanospirillaceae and formed a distinct subcluster at the base of the radiation of the genus Marinomonas. The highest sequence similarity (96.0 %) of the novel isolate was found to the type strains of Marinomonas fungiae JCM 18476^T and Marinomonas ostreistagni DSM23425^T. The whole genome-based phylogeny and differences in cellular fatty acids and polar lipids readily distinguished strain HB171799^T from all the closely related validly published type strains. Strain HB171799^T is therefore suggested to represent a novel species of a new genus in the family Oceanospirillaceae, for which the name Maribrevibacterium harenarium gen. nov., sp. nov. is proposed. The type strain is HB171799^T (=CGMCC 1.16727^T=JCM 33332^T).

Fate and stability of polyamide-associated bacterial assemblages after their passage through the digestive tract of the blue mussel Mytilus edulis

We examined whether bacterial assemblages inhabiting the synthetic polymer polyamide are selectively modified during their passage through the gut of Mytilus edulis in comparison to the biopolymer chitin with focus on potential pathogens. Specifically, we asked whether bacterial biofilms remained stable over a prolonged period of time and whether polyamide could thus serve as a vector for potential pathogenic bacteria. Bacterial diversity and identity were analysed by 16S rRNA gene fingerprints and sequencing of abundant bands. The experiments revealed that egested particles were rapidly colonised by bacteria from the environment, but the taxonomic composition of the biofilms on polyamide and chitin did not differ. No potential pathogens could be detected exclusively on polyamide. However, after 7days of incubation of the biofilms in seawater, the species richness of the polyamide assemblage was lower than that of the chitin assemblage, with yet unknown impacts on the functioning of the biofilm community.

Litoribrevibacter euphylliae sp. nov., isolated from the torch coral Euphyllia glabrescens

Strain Eup a-2^T, isolated from the torch coral Euphyllia glabrescens, was characterized using a polyphasic taxonomy approach. Cells of strain Eup a-2^T were Gram-negative, aerobic and motile by three polar flagella and formed translucent colonies. Optimal growth occurred at 25 °C, pH 6-8 and in the presence of 2-4 % NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Eup a-2^T belonged to the genus Litoribrevibacter and showed the highest levels of sequence similarity with respect to Litoribrevibacter albus Y32^T (97.8 %). Strain Eup a-2^T contained summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0 as the predominant fatty acids. The predominant isoprenoid quinone was Q-8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphophatidylglycerol. Genomic DNA G+C content of strain Eup a-2^T was 49.1 mol%. The DNA-DNA hybridization value for strain Eup a-2^T with L. albus Y32^T was less than 30 %. Differential phenotypic properties, together with the phylogenetic inference, demonstrate that strain Eup a-2^T should be classified as a novel species of the genus Litoribrevibacter, for which the name Litoribrevibactereuphylliae sp. nov. is presented. The type strain is Eup a-2^T (=BCRC 81004^T=LMG 29725^T=KCTC 52438^T).

Neptuniibacter pectenicola sp. nov. and Neptuniibacter marinus sp. nov., two novel species isolated from a Great scallop (Pecten maximus) hatchery in Norway and emended description of the genus Neptuniibacter

Nine isolates obtained from a great scallop hatchery in Norway were characterized using a polyphasic approach. Strains were Gram-negative, aerobic and motile rods with oxidative metabolism. Phylogenetic analysis based on the sequences of 16S rRNA and rpoB genes showed that these strains formed two different groups associated with members of the genus Neptuniibacter. DNA-DNA hybridization (DDH) and Average Nucleotide Identity (ANI) demonstrated that the isolates constituted two novel species of this genus, which can be phenotypically differentiated from their closest relatives. The names Neptuniibacter marinus sp. nov. and Neptuniibacter pectenicola sp. nov are proposed, with ATR 1.1^T (=CECT 8938^T=DSM 100783^T) and LFT 1.8^T (=CECT 8936^T=DSM 100781^T) as respective type strains.