Pseudidiomarina fusca sp. nov., Isolated from the Surface Seawater of the Western Pacific Ocean.

The Gram-negative marine bacterium GXY010T, which has been isolated from the surface seawater of the western Pacific Ocean, is aerobic, non-motile and non-flagellated. Strain GXY010T exhibits growth across a temperature range of 10-42 °C (optimal at 37 °C), pH tolerance from 7.0 to 11.0 (optimal at 7.5) and a NaCl concentration ranging from 1.0 to 15.0% (w/v, optimal at 5.0%). Ubiquinone-8 (Q-8) was the predominant isoprenoid quinone in strain GXY010T. The dominant fatty acids (>10%) of strain GXY010T were iso-C15:0 (14.65%), summed feature 9 (iso-C17:1ω9c and/or 10-methyl C16:0) (12.41%), iso-C17:0 (10.85%) and summed feature 3 (C16:1ω7c and/or C16:1ω6c) (10.41%). Phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), unidentifiable glycolipid (GL) and four non-identifiable aminolipids (AL1-AL4) were the predominant polar lipids of strain GXY010T. The genomic DNA G+C content was identified as a result of 48.0% for strain GXY010T. The strain GXY010T genome consisted of 2,766,857 bp, with 2664 Open Reading Frames (ORFs), including 2586 Coding sequences (CDSs) and 78 RNAs. Strain GXY010T showed Average Nucleotide Identity (ANI) values of 73.4% and 70.6% and DNA-DNA hybridization (DDH) values of 19.2% and 14.5% with reference species Pseudidiomarina tainanensis MCCC 1A02633T (=PIN1T) and Pseudidiomarina taiwanensis MCCC 1A00163T (=PIT1T). From the results of the polyphasic analysis, a newly named species, Pseudidiomarina fusca sp. nov. within the genus Pseudidiomarina, was proposed. The type strain of Pseudidiomarina fusca is GXY010T (=JCM 35760T = MCCC M28199T = KCTC 92693T).

Spatial and temporal change determined co-occurrence networks stability and community assembly processes of epipelagic seawater microbial community in the Nordic Sea.

The Nordic Sea has a vital impact on the global climate change, occupies a significant status in the physical oceanography research, on account of its intersection of complex ocean currents. To explore the influence of seasonal and spatial heterogeneity in its epipelagic seawater on the microbial community structure, a total of 54 seawater samples from 18 stations and 3 water layers (0 m, 50 m, 100 m) were collected in the summer of 2017 and the autumn of 2018 from the Norwegian Sea, the Greenland Sea and the vicinity of Jan Mayen Island in the Nordic Sea. Alpha- and Beta- diversity analysis showed that significant differences were found between characteristic bacterial groups in detached or mixed currents of corresponding seasons, as endemic OTUs with seasonal and ocean current characteristics which revealed the existence of spatiotemporal patterns of microbial communities in the Nordic Sea. Moreover, co-occurrence networks were conducted to show different degree of complexity and stability of microbial community response to spatiotemporal dynamic changes. Furthermore, the flow and collision between ocean currents do have an impact on the community assembly processes by affecting the migration and dispersal of microbial communities. This study reflects the response of microbial communities to the spatiotemporal dynamics and reveals the microbial community assembly mechanisms under complex hydrological condition represented in the Nordic Sea.

Puteibacter caeruleilacunae gen. nov., sp. nov., a facultatively anaerobic bacterium isolated from Yongle Blue Hole in the South China Sea.

Blue holes are unique geomorphological units characterized by steep redox and biogeochemical gradients. Yongle Blue Hole is located on the largest atoll (Yongle Atoll) of the western Xisha Islands in the South China Sea. A Gram-stain-negative, facultatively anaerobic, non-motile, non-flagellated marine bacterium with creamy white colonies, designated JC036T, was isolated from Yongle Blue Hole. Cells were short-rod-shaped and catalase-negative. 16S rRNA gene sequence analysis showed that sequence similarities were lower than 91.6 % against all validly named species in the family Prolixibacteraceae; a reconstructed phylogenetic tree indicated that strain JC036T formed a lineage with strains in the family Prolixibacteraceae. Growth occurred at 4-37 °C (optimum, 28 °C), at pH 5.0-9.0 (optimum, 7.0) and in the presence of 2-6 % (w/v) NaCl (optimum, 3 %). The prevalent isoprenoid quinone of strain JC036T was menaquinone-7 (MK-7). Iso-C15 : 0 and iso-C17 : 0 3-OH were the predominant fatty acids. The major polar lipids included a phospholipid, phosphatidylethanolamine, an aminophospholipid and four unidentified lipids. The genomic DNA G+C content of strain JC036T was 37.8 mol%. Based on physiological and biochemical characteristics and whole genome comparisons, we propose a new genus and species, Puteibacter caeruleilacunae gen. nov., sp. nov., within the family Prolixibacteraceae. The type strain of Puteibacter caeruleilacunae is JC036T (=JCM 33128T=MCCC 1K03579T). From this study, a deeper understanding of the community of the microorganism and their roles in biogeochemical cycles, especially anaerobic bacteria, is provided.