Diversity Of Cultivated Bacteria Isolated From Deep Seas In Tropical Pacific Ocean And Identification Of A New Species Oceanicola Eastpnp

Marine environments are unique habitats for microbial communities. The microbial diversity studies have been carried out widely at different marine environments in recent years, resulting in the understanding of the important functions of deep-sea microorganisms in ocean. The tropical Pacific, which spans the waters of the equatorial Pacific to the eastern Indian Ocean, is a unique deep-sea region in the earth. In this environment, Prokaryotes dominate many tropical Pacific ecosystems and colonize a variety of niches where they live under extreme conditions. As the dominant biomass component of ecosystems, microbial communities control many processes within the marine environment, like primary production, turnover of biogenic elements, degradation of the organic matter and also mineralization of xenobiotics.In this report, the oceanic bacterial community structure was investigated by molecular phylogenetic analysis applied to the cultivation-dependent microorganisms on the base of water and sediment samples taken from the the tropical Pacific. 210 bacteria were isolated from the water and sediments. With the phylogenetic analyses by direct sequencing of 16S rRNA genes, the results revealed that 29 different genera were identified and characterized. 17 genera were identified from the water samples and 25 genera from the sediments samples. The research results have indicated that the Gram-negative bacteria were abundant in the strains from sea water samples while the Gram-positive bacteria were dominant in the strains from sediment samples。In particular, genus Halomonas (mainly Halomonas sp.) had a higher relative abundance in most samples. 11 species and 87 isolates were related to genus Halornonas. According to the results of phylogenetic analysis based on cultivation-independent samples, the isolates were clustered into four distinct groups. The majority of the isolates were deeply related to the phylumγ-Proteobacteria, some were related to Actinobacteria and Firmicutes, and only four strains were related toα-Proteobacteria. And 18 strains isolated from Pacific had a abilitu of chromate(VI)) resistance.a Gram-negative, non-motile, rod-shaped bacterium, strain B-3030 that accumulate poly-b-hydroxybutyrate granules was isolated from 1500m deep water of the East Pacific Nodule Province. Growth occurred at NaCl concentrations between 1% and 10% and at temperatures between 10～40℃. Strain B-3030 contained C18: 1 (?)7c (87.79%) C16 : 0 (6.63%) C18 : 1 methyl (2.18%) C18 : 0 (2.18%) as the predominant fatty acids. The G+C content of the genomic DNA was 64.9 mol%. A phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain B-3030 belonged to a clade within the genus Oceanicola in the Alphaproteobacteria, the highest sequence similarities being found with respect to Oceanicola batsensis (96.3%). Strain B-3030 could be clearly distinguished from other Oceanicola species on the basis of the genotypic, phenotypic and phylogenetic data. Thus, it is proposed that strain B-3030 represents a novel species of the genus Oceanicola, with the name Oceanicola eastpnp sp. nov.. The type strain is B-3030 (=MCCC 1A00861).Marine bacteria from the samples of sea sediments and seawater were directly plated on isolation media and the biodiversity of isolates was examined with DNA fingerprinting. 107 single colonies were obtained from the media. ARDRA with enzyme RsaI and MspI revealed 13 operational taxonomic units(OTU)which were dominated by OTU4 group which accounts for 17 isolates, and OTU10 group which accounts for 9 isolates. The biodivemity of isolates from these two dominant OTU groups was further investigated by a genomic fingerprinting technique. The data indicated rich diversity profiles of marine microorganisms were presented in the East Pacific and reveiled that ARDRA is advantageous over the diversity of microorganisms. Also, it suggested that analysis of 16S rRNA sequence is a practical method for fingerprinting of genomicDNA, which can be used for quick identification and classification of the bacteria.