| The marine sediments of offshore are found to have abundant microbial resources, so it is value to excavate potential novel species and study the microbial diversity. To study the microbial community diversity and the succession of bacterial florain, find potential novel species and discuss the feasibility of this enrichment cultivation method, the traditional enrichment cultivation method combined with Roche 454 FLX high-throughput sequencing technologies was used based on the marine sediments of Xiaoshi Island. The main results of this study are as follows:1. The traditional enrichment cultivation method and Roche 454 FLX high-throughput sequencing technologies analyzed the microbial diversity of offshore sediment samples in weihai before and after the enrichment, especially the diversity of Bacteroidetes bacteria, and found that the richness is reduced after enrichment, but the enrichment of Proteobacteria, Firmicutes, Bacteroidetes and Fusobacteria was obvious.The traditional enrichment cultivation method and Roche 454 FLX high-throughput sequencing technologies found that the abundance and diversity of bacteria are reduced after enrichment culture. The results showed that 584 isolates used enrichment cultivation method were distributed in 270 species of four phyla, the most abundant phylum was Firmicutes, then Proteobacteria, Bacteroidetes and Actinobacteria decreased successively. With the extension of enriched time, the proportion of Bacteroidetes increased firstly and then decreased. The Roche 454 FLX high-throughput sequencing technology found 4390 OTU were distributed in 58 phyla, the most abundant phylum was Proteobacteria, then Chloroflexi, Firmicutes, Fusobacteria and Bacteroidetes decreased successively, further, the enrichment of Proteobacteria, Firmicutes, Bacteroidetes and Fusobacteria was obvious. The dominant bacterial communities and the richness detected by the two methods were not completely consistent, indicating that the enrichment cultivation has some limitations but can promote the enrichment of Bacteroidetes, demonstrated that there were abundant microbial resources and dark matter in marine sediments deserved to further development. The enrichment cultivation method was effective and can provide certain reference significance to enrich more Bacteroidetes novel strains.2. A novel Bacteroidetes strains which was isolated from marine sediment of the coast of Weihai were characterized using a polyphasic approach, designated HF08T, a novel species in a new genus of the family Prolixibacteraceae is proposed, with the name Roseimarinus sediminis gen. nov., sp. nov.A Gram-stain-negative, facultatively anaerobic, non-motile and pink-pigmented bacterium, designated HF08T, was isolated from marine sediment of the coast of Weihai, China. Cells were rod-shaped, oxidase- and catalase-positive. The isolate grew optimally at 33℃, pH 7.5-8.0 and with 2-3%(w/v) NaCl. The dominant cellular fatty acids were iso-C15:0, anteiso-C15:0 and iso-Ci4:o. The major polar lipids are phosphatidylethanolamine and two unknown lipids. MK-7 was the major respiratory quinone and the DNA G+C content was 44.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was a member of the class Bacteroidia, and shared 88-90% sequence similarity with the closest genera Sunxiuqinia, Prolixibacter, Draconibacterium, Mariniphaga and Meniscus. Based on the phylogentic and phenotypic evidences, a novel species in a new genus of the family Prolixibacteraceae is proposed, with the name Roseimarinus sediminis gen. nov., sp. nov. The type strain is HF08T (= DSM 28824 T=KCTC 42261T=CICC 10901T).3. A novel Bacteroidetes strains which was isolated from marine sediment of the coast of Weihai were characterized using a polyphasic approach, designated FA423T, is considered to represent a novel species of the genus Mangrovibacterium, for which the name Mangrovibacterium marinum sp. nov. is proposed.A Gram-stain negative, facultatively anaerobic, non-motile and rod shaped bacterium, designated FA423T, was isolated from a marine sediment obtained off the coast of Weihai, China. Strain FA423T was found to grow at 17-42℃ (optimum, 33℃) and pH 5.5-8.0 (optimum,7.0-7.5) in the presence of 0.5-6.0%(w/v) NaCl (optimum,1.0-2.0%). Cells were found to be catalase positive and oxidase negative. Phylogenetic analysis of its 16S rRNA gene sequence revealed that strain FA423Tis a member of the genus Mangrovibacterium and exhibits the highest sequence similarity (95.9%) to the type strain of Mangrovibacterium diazotrophicum. The dominant cellular fatty acids were identified as summed feature 4 (iso-C17：1 I and/or anteiso-C17:1 B) and iso-C18:0. Menaquinone MK-7 was found to be the sole respiratory quinone. The major polar lipids were found to be an unidentified lipid and an unidentified phospholipid. The DNA G+C content of strain FA423T is 47.4 mol%. Based on the phylogenetic and phenotypic characteristics, strain FA423T is considered to represent a novel species of the genus Mangrovibacterium, for which the name Mangrovibacterium marinum sp. nov. is proposed. The type strain is FA423T (=DSM 28823T=KCTC 42253T=CICC 10903T).4. A novel Bacteroidetes strains which was isolated from marine sediment of the coast of Weihai were characterized using a polyphasic approach, designated FA102T, represents a novel genus and species, for which the name Ancylomarina subtile gen. nov., sp. nov. is proposed.A Gram-stain-negative, facultatively anaerobic, moderately halophilic, filamentous, non-motile bacterium, designated FA102T, was isolated from marine sediment of the coast of Weihai, China. The isolate grew optimally at 28℃, pH 7.5 and with 2%(w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain FA102T formed a distinct evolutionary lineage within the family Marinifilaceae and its closest relative was Marinifilum fragile JCM 15579T (93.1% sequence similarity). The DNA G+C content of the novel strain was 36.5 mol%. The predominant cellular fatty acids and respiratory quinone were iso-C15:0 and MK-7, respectively. The major polar lipids are phosphatidylethanolamine and two unknown aminolipids. On the basis of the phylogentic, phenotypic and physiological data, strain FA102T represents a novel genus and species, for which the name Ancylomarina subtile gen. nov., sp. nov. is proposed. The type strain of Ancylomarina subtile is FA102T (=KCTC 4225T=DSM 28825T=CICC 10902T).A novel order within class Bacterioidia named Marinilabiliales was proposed on the basis of 16S rRNA gene sequence-based phylogenetic clustering and physiological and chemotaxonomic characteristics. The class Bacterioidia would be contains two orders, Bacteroidales and Marinilabiliales. |
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