Studies On Polyphasic Taxonomy Of Three Marine Bacteria

There are abundant microorganism resources in the vast, unique and complicated marine entironment where embraces at least 1×106～2×108 species. In order to acclimatize themselves to extreme conditions, such as high salinity, high pressure, low nutrition as well as low light, marine microorganisms with biodiversities on spiecies, genotypes and ecological functions. So, it is considered to be a natural treasury of scientific research and production practice.The marine microorganisms, however, which have been known already are less than 1% of its total amount, and the cultivation rate of them is only 0.001%～0.1%.Thus, isolating and cultivating the novel microorganisms and performing phylogenetic taxonomic identification are significant and urgent for marine microorganism research.In this research, In accordance with the principle of polyphasic taxonomy, a systematic study had been conducted on the taxonomy of three marine bacteria (strains HB09001, HB09002 and HB09003) isolated from the South China Sea.Strain HB09001T is Gram-positive, aerobic, non-motile, non-spore-forming, Branching hyphal forms with a size range of 0.57-0.80×0.75-1.12μm.Colonies are bright yellow. Growth occurs between pH 5.0 and 10.2, between 4 and 45℃, and in 0-5%(w/v) NaCl. The cell-wall contains L-ornithine as the major diagnostic diamino acid in the peptidoglycan. MK-8(H4) is the predominant menaquinone. The major polar lipid profile is PI, PE, PG, DPG and a GL. Major cellular fatty acids are iso-C18:1ω9c, iso-C16:0, iso-C15:0 and C17:0. The DNA G+C content is 69.6 mol%. The highest homology is 96.7% with Fodinibacter luteus DSM 21208T base on 16S rRNA gene sequence alignment analysis. Strain HB09001T represents a novel genus and species of family Intrasporangiaceae,for which the name Ornithinibacter aureus gen. nov.,sp. nov. is proposed.Strain HB09002 is Gram-negative, non-motile, irregular cocci and the diameter is 0.40-0.58μm. Colonies are saffron yellow. Growth occurs between pH 5.0 and 10.2, between 10 and 37℃, and in 0-2%(w/v) NaCl. Oxidase-positive, catalase-positive, Urease-negative. Does not reduce nitrate. Can't degrade starch, cellulose, gelatin, Tween 20 and Tween 80. Milk coagulation and peptonization are negative. Indole is produced. H2S is not produced. The methyl red test is negative, but V-P test is positive. The cell-wall contains meso-DAP as the major diagnostic diamino acid in the peptidoglycan. The DNA G+C content is 67.8 mol%. The highest homology is 97.1% with Paracoccus koreensis JCM 21670T base on 16S rRNA gene sequence alignment analysis. Thus, we represent strain HB0092 is a species of genus Paracoccus. Using other identification methods such as genomic DNA-DNA hybridization in subsequent study will be beneficial for exact estimation of its phylogenetic status.Strain HB09003 is Gram-positive, motile, irregular long rods with a size range of 0.40-0.50×1.30-3.20μm. Colonies are cream. Growth occurs between pH 5.0 and 10.7, between 10 and 45℃, and in 0-15%(w/v) NaCl. Oxidase-positive, catalase-positive, Urease-negative. Nitrate reduction-positive.Able to degrade starch, but not cellulose, gelatin, Tween 20 and Tween 80. Milk coagulation and peptonization are negative. Indole is produced. H2S is not produced. The methyl red test is negative, but V-P test is positive. The DNA G+C content is 34.1 mol%. The highest homology is 97.1% with Gracilibacillus ureilyticus CGMCC 1.7727T base on 16S rRNA gene sequence alignment analysis. Thus, we represent strain HB09003 is a species of genus Gracilibacillus. Using other identification methods such as genomic DNA-DNA hybridization in subsequent study will be beneficial for exact estimation of its phylogenetic status.