bWe report the genome sequence of actinobacterial strain IMCC13023, isolated from arctic fjord seawater. Phylogenetic analysis of 16S rRNA gene showed that the strain is related to "Candidatus Aquiluna rubra." The genome information suggests that strain IMCC13023 is a photoheterotroph carrying actinorhodopsin, with the smallest genome ever reported for a free-living member of the Actinobacteria.

Members of the genus Nocardia are widespread in diverse environments; a wide range of Nocardia species are known to cause nocardiosis in several animals, including cat, dog, fish, and humans. Of the pathogenic Nocardia species, N. seriolae is known to cause disease in cultured fish, resulting in major economic loss. We isolated two N. seriolae strains, CK-14008 and EM15050, from diseased fish and sequenced their genomes using the PacBio sequencing platform. To identify their genomic features, we compared their genomes with those of other Nocardia species. Phylogenetic analysis showed that N. seriolae shares a common ancestor with a putative human pathogenic Nocardia species. Moreover, N. seriolae strains were phylogenetically divided into four clusters according to host fish families. Through genome comparison, we observed that the putative pathogenic Nocardia strains had additional genes for iron acquisition. Dozens of antibiotic resistance genes were detected in the genomes of N. seriolae strains; most of the antibiotics were involved in the inhibition of the biosynthesis of proteins or cell walls. Our results demonstrated the virulence features and antibiotic resistance of fish pathogenic N. seriolae strains at the genomic level. These results may be useful to develop strategies for the prevention of fish nocardiosis.

Gaetbulibacter marinus sp. nov., isolated from coastal seawater, and emended description of the genus Gaetbulibacter Seung-Jo Yang and Jang-Cheon Cho Correspondence Jang-Cheon Cho chojc@inha.ac.kr Division of Biology and Ocean Sciences, Inha University, Yonghyun-Dong, Incheon 402-751, Republic of Korea A Gram-negative, yellow-coloured, chemoheterotrophic, non-motile, strictly aerobic, rod-shaped bacterium, designated IMCC1914 T , was isolated from coastal surface seawater of the Yellow Sea, Korea. The temperature, pH and NaCl ranges for growth were 3-37 6C, pH 8.0-11.0 and 0.5-4.0 %. The DNA G+C content of the strain was 38.1 mol% and the major cellular fatty acids were iso-C 15 : 1 (32.1 %), iso-C 15 : 0 (20.6 %) and iso-C 17 : 0 3-OH (7.8 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain IMCC1914T was related most closely to Gaetbulibacter saemankumensis SMK-12 T , with a sequence similarity of 96.2 %. On the basis of phylogenetic data and several distinct phenotypic characteristics, strain IMCC1914T (5KCCM 42380 T 5NBRC 102040 T ) could be assigned to the genusGaetbulibacter as the type strain of a novel species, for which the name Gaetbulibacter marinus sp. nov. is proposed. In addition, an emended description of the genus Gaetbulibacter is presented.

Background Although microbioa‐based therapies have shown putative effects on the treatment of non‐alcoholic fatty liver disease (NAFLD), it is not clear how microbiota‐derived metabolites contribute to the prevention of NAFLD. We explored the metabolomic signature of Lactobacillus lactis and Pediococcus pentosaceus in NAFLD mice and its association in NAFLD patients. Methods We used Western diet‐induced NAFLD mice, and L. lactis and P. pentosaceus were administered to animals in the drinking water at a concentration of 10 9 CFU/g for 8 weeks. NAFLD severity was determined based on liver/body weight, pathology and biochemistry markers. Caecal samples were collected for the metagenomics by 16S rRNA sequencing. Metabolite profiles were obtained from caecum, liver and serum. Human stool samples (healthy control [ n = 22] and NAFLD patients [ n = 23]) were collected to investigate clinical reproducibility for microbiota‐derived metabolites signature and metabolomics biomarker. Results L. lactis and P. pentosaceus supplementation effectively normalized weight ratio, NAFLD activity score, biochemical markers, cytokines and gut‐tight junction. While faecal microbiota varied according to the different treatments, key metabolic features including short chain fatty acids (SCFAs), bile acids (BAs) and tryptophan metabolites were analogously restored by both probiotic supplementations. The protective effects of indole compounds were validated with in vitro and in vivo models, including anti‐inflammatory effects. The metabolomic signatures were replicated in NAFLD patients, accompanied by the comparable levels of Firmicutes / Bacteroidetes ratio, which was significantly higher (4.3) compared with control (0.6). Besides, the consequent biomarker panel with six stool metabolites (indole, BAs, and SCFAs) showed 0.922 (area under the curve) in the diagnosis of NAFLD. Conclusions NAFLD progression was robustly associated with metabolic dys‐regulations in the SCFAs, bile acid and indole compounds, and NAFLD can be accurately diagnosed using the metabolites. L. lactis and P. pentosaceus ameliorate NAFLD progression by modulating gut metagenomic and metabolic environment, particularly tryptophan pathway, of the gut‐liver axis.

A Gram-negative, yellow-coloured, non-motile, chemoheterotrophic, strictly aerobic, rod-shaped bacterium, designated IMCC1616T, was isolated from the marine polychaete Periserrula leucophryna inhabiting tidal flat sediment of the Yellow Sea, and characterized by a polyphasic approach. The temperature, pH and NaCl ranges for growth were 3–37 °C, pH 5.0–11.0 and 0.5–7.5 %. Based on 16S rRNA gene sequence similarity analyses, the strain was most closely related to members of the genera Lutibacter (90.7 %), Tenacibaculum (89.2–90.4 %) and Polaribacter (88.4–90.2 %). Phylogenetic analysis using three treeing algorithms based on 16S rRNA gene sequences indicated that the strain formed a distinct lineage within the family Flavobacteriaceae. The DNA G+C content of the strain was 40.1 mol% and the predominant cellular fatty acids were iso-C15 : 0 (16.5 %), anteiso-C15 : 0 (10.9 %), iso-C17 : 0 3-OH (8.8 %) and iso-C17 : 1 ω9c (8.2 %). The DNA G+C content, large amount of iso-C17 : 1 ω9c and several phenotypic characteristics, including growth temperature and catalase activity, differentiated the strain from other related genera in the family. Therefore, from the taxonomic evidence collected in this study, it is proposed that strain IMCC1616T represents a new genus and species named Lutimonas vermicola gen. nov., sp. nov. The type strain of Lutimonas vermicola is strain IMCC1616T (=KCCM 42379T =NBRC 102041T).