Taxonomic Analysis And Related Research Of Oceanobacillus Pacificus Sp.nov. And Other Five Novel Bacteria From The South Pacific Gyre

The South Pacific Gyre (SPG) is the largest gyre and the most oligotrophic areain the world, in the meantime, the center of SPG is farther from continents than thecenter of any other gyre. Life in the seawater and sediment of SPG remains barelyunknown as the center of the gyre is scarcely influenced by human activities.Identification of novel bacteria is always a hot spot of science research. Microbialresources in marine environment are abundant and many of them are quietly differentfrom species that have already been known. Therefore SPG is an ideal region forexploring the novel bacteria of marine environment. In this study, five novel bacteriaisolated from the South Pacific Gyre have been investigated using taxonomic analysisby a polyphasic approach, which laid a foundation for better development andapplication of microorganism resource.XH204Twas isolated from deepsea sediment of the South Pacific Gyre. Cells ofXH204Twere Gram-staining-positive, obligately aerobic and peritrichouslyflagellated straight rods which produce ellipsoidal endospores subterminallypositioned within swollen sporangia. Approximately0.3–0.8×3.1–4.7μm. The G+Ccontents of strain XH204Twas38.8mol%. The dominant cellular fatty acids (>10%of total) were anteiso-C15:0, iso-C14:0, and iso-C16:0. The major respiratory quinone wasMK-7. Cell wall of strain XH204Tcontained meso-diaminopimelic acid (meso-DAP)as the diagnostic diamino acid, and ribose, glucose and galactose as the majorwhole-cell sugars. Polar lipids consist of phosphatidylglycerol (PG),phosphatidylethanolamine (PE), phosphatidylinositol (PI), one unidentifiedaminolipid (AL) and one unidentified glycolipid (GL). Strain XH204Tshowed thehighest sequence similarity with Oceanobacillus profundus CL-MP28T(95.6%).Based on the phenotypic, chemotaxonomic and phylogenetic analysis, strain XH204T represents a novel species of the genus Oceanobacillus, for which the nameOceanobacillus pacificus sp. nov. is proposed.SW096Tand XH116were Gram-staining-negative, aerobic, yellow-pigmented,rod-shaped bacteria isolated from surface and deep seawater of the South Pacific Gyrerespectively. The16S rRNA gene sequence similarity value between SW096TandXH116was99.0%, the closest relatives of the two isolates was Algibacter aestuariiKYW371T(96.69%16S rRNA gene sequence similarity). The dominant cellular fattyacids were iso-C15:0, iso-C15:1G, iso-C15:03-OH and iso-C17:03-OH. The G+Ccontent of strain SW096Tand XH116were30.39and31.06mol%respectively. Themajor respiratory quinone was menaquinone6(MK-6). The major polar lipids werephosphatidylethanolamine, three unidentified aminolipids, two unidentifiedglycolipids and two unidentified polar lipids. Based on the phenotypic,chemotaxonomic and phylogenetic analysis, strains SW096Tand XH116represent anovel species of the genus Algibacter, for which the name Algibacter pacificus sp.nov. is proposed.Strain SW026Twas isolated from surface seawater of the South Pacific Gyre.Cells of SW026Tare Gram-negative, non-encapsulated, non-flagellated,non-sporeforming and slightly curved rods. Strain SW026Tshowed the highestsequence similarity with Arcobacter bivalviorum LMG26154T(96.84%). Cells growwell under both aerobic and microaerobic conditions with no significant differences.Weak growth was obtained in anaerobic conditions at37oC; The G+C content ofstrain SW026Tis30.2mol%. Menaquinone-6(MK-6) was the major respiratoryquinone in SW026T. The dominant cellular fatty acids (>10%of total) are C18:1ω7c,C16:1ω7c and C16:0. The major respiratory quinone is menaquinone6(MK-6). Basedon the phenotypic, chemotaxonomic and phylogenetic analysis, strain SW026Trepresents a novel species of the genus Arcobacter, for which the name Arcobacterpacificus sp. nov. is proposed.Strain SW028Twas isolated from surface seawater of the South Pacific Gyre.Cells of SW028Tare Gram-negative, non-encapsulated, non-sporeforming andslightly curved rods, Motile by means of a single polar flagellum. Cells grow well under both aerobic and microaerobic conditions with no significant differences. Weakgrowth was obtained in anaerobic conditions at37oC; Strain SW028Tshowed thehighest sequence similarity with Arcobacter molluscorum LMG25693T(95.50%).The G+C content of strain SW028Tis27.1mol%. The major respiratory quinone isMK-6. The dominant cellular fatty acids (>10%of total) are C16:0,C18:1ω7c andC16:1ω7c. The major respiratory quinone is menaquinone6(MK-6).S Based on thephenotypic, chemotaxonomic and phylogenetic analysis, strain SW028Trepresents anovel specie of the genus Arcobacter, for which the name Arcobacter aquimaris sp.nov. is proposed.Four new species of marine bacteria were identified in this study, and they wereOceanobacillus pacificus sp. nov.，Algibacter pacificus sp. nov.，Arcobacter pacificussp. nov. and Arcobacter aquimaris sp. nov. respectively. the four new species couldefficiently produce a variety of biological active substance such as basophilicextracellular enzymes, chitinase, carotenoids and AHLs. and have great potential inindusty, environmental protection and biological control. The results in this studyhave enriched the deepsea microbial resources and lay a foundation for betterdevelopment and application of microorganism resource.