| Recently, with the development of industry and the growing demand for metal, many developed countries have paid their attentions to the ocean for new resources. More attentions have been paid on polymetallic nodules because of the abundance of manganese (Mn), iron(Fe), copper (Cu), cobalt (Co), nickel (Ni), platinum (Pt) and many other metals.The metallic taste and concentration degree in Pacific is high, total up to 1.7 trillions tons, made it a prospect area for ocean polymetallic resources development.It is widely accepted that the nodules are formed in many ways, including bio-driving process which was also called biominerralization. Microorganisms are believed to paly an important role in the cycle of metal in many environments. There is evidence that biofilm microorganisms provide matrix for the precipitation of Mn. Hence, the investigation of the microbial communities in nodules became more and more improtant.Phylogenetic analyses of the diversity of cultivable bacteria in the Pacific nodule province were carried out in our study. Strains were also subjected to enzymatic text after the identification, including amylase, gelatinase and esterase activities. Screening of the manganese oxidation bacteria was carried out by texting on the K medium and staining by Leukoberbelin blue. Besides,3 novel bacteria isolated from deep water of the South China Sea were identified using ployphasic approach.Deep-sea sediment and water samples were collected from the east Pacific in Augest,2013. The samples were coating on 2216E、R2A and oligonucleotides nutrent medium at 4℃、16℃ and 28℃ conditions.629 strains were isolated and 237 strains of them were identified by 16S rRNA gene scequencing technology. Phlogenetic analysis of these 237 bacterial strains showed that bacteria isolated from the East Pacific polymetallic area belonged to four phyla of bacteria such as Proteobacteria,, Actinobacteria, Bacteroidetes and Firmicutes.237 strains divided into 40 genera and 75 species. γ-Proteobacteria dominated the microbial community of the nodule province with 133 strains, which belong to 36 species,13 genera, accounting for 56.12% percent of the total. a-Proteobacteria includes 77 strains belonging to 24 species,13 genera, accounting for 32.49% of the total. Actinobacteria has 17 strains, belonging to 5 species and 5 genera, accounting for 7.17% of the total. Bacteroidetes accounting for 3.0% of the total by 7 strains, which belong to 7 species,6 genera.3 Firmicutes strains were isolated and divided into 3 species and 3 genera, accounting for 1.27% of the total. Pseudomonas, Halomonas, Sulfitobacter, Alteromonas and Acinetobacter play the role of dominant genera. The dominant species are Sulfitobacter pontiacus (26), Halomonas meridian (23), Alteromonas macleodi (20), Acinetobacter venetianus (12) and Pseudomonas Stutzeri (9). In terms of the enzymic characteristics,22 species (69 strains) of them were detected of amylas activity,29 species (66 strains) were detected of gelatinase (Tween 20) activity,23 species (67 strains) were detected of gelatinase (Tween 40) activity and 10 species (24 strains) of them can produce quruom sensing signal molecule.Among the 237 strains which were subjected to phylogenetic analysis,144 of them were isolated from water,34 of them were from sediment and 58 of them were from nodules. Community of bacteria from showed the highest diversity, strain from here can be divided into 31 genera,43 species. Bacteria isolated from the nodules can be divided into 17 genera,26 species and strains from sediment can be divided into 10 genera,14 species. Among the bacteria isolated from the nodules, also isolated according to previous study, while other 12 genera were isolated for the first time.The 3 novel bacteria are designated as ZH137, ZL136 and ZH114 in the lab. Cells of strain ZH137T are Gram-staining-negative, strictly aerobic, rod-shaped (approximately 0.5 - 0.6 μm in width and 1.0-1.2 μm in length). Colonies on MA are tiny, translucent and cream-colored. Growth occurs at 4-37℃ on 2216E, pH 7.0 - 9.0 and in presence of 0-13% NaCl in MB. Cells are positive for oxidase and catalase activities and capable of hydrolyzing starch, DNA and gelatin. The major fatty acids are C18:1ω7c and/or C18:1ω6c (43.4%),11-methyl C18:1ω7c (20.9%), C18:0 (15.0%) and C16:0 (13.7%). The major polar lipids are phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), two glycolipids (GL1, GL2) and two unidentified lipids (LI, L2). The major respiratory quinone is ubiquinone Q-10 and the DNA G+C content of the type strain is 55.2 mol%. The 16S rRNA gene scequences analysis indicated that strain ZH137T shows the highest similarity with Devosia geojensis BD-c194T (96.1%). On the basis of phenotypic and phylogenetic studies, strain ZH137T was considering to represent a novel species in the genus Devosia, for which the name Devosia aquimarina sp. nov. is proposed.Cells of strain ZL136T are Gram-negative-staining, aerobic, non-flagellated, non-gliding and long rod-shaped (0.3-0.4 μm in width and 1.2-1.3 μm in length, in exponential phase) (Fig. S2). Growth occurs at 4-37 ℃, pH 6.0-10.0 and in presence of 0-12% NaCl (w/v) in marine broth 2216. Seawater isnot required for growth. Strain ZL136T do not produce BChl a during aerobic growth in the dark. The predominant fatty acids of strain ZL136T are summed feature 8 (C18:1ω7c and/or C181ω6c) (64.5%), C,8:o (9.5%), C16:0 (8.0%) and 11-methyl C18:1ω7c (7.3%). The polar lipids found in strain ZL136T are phosphatidylglycerol (PG) phosphatidylcholine (PC), phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG) and an unidentified lipid. The major respiratory quinone of strain ZL136T is Q-10 and the DNA G+C content is67.0 mol%. The 16S rRNA gene scequences indicates that strain ZL136T is most closly to the Roseivivax halodurans OCh 239T with the highest similarity of 97.0%. On the basis of phenotypic and phylogenetic studies, strain ZL136T was considering to represent a novel species in the genus Roseivivax, for which the name Roseivivax marinus sp. nov.is proposed.Cells of strain ZH114T are facultative anaerobic, chemoheterotrophy, moderately halophilic, EPS-producing, non-motile and rod-shaped (approximately 0.8 μm in width and 1.2 μm in length). It do not produce PHA granules and BChla. Growth occurs at 4-37 ℃. pH 6.0-10 and in presence of 0-19% NaCl (w/v). Gelatinase, amylase and ONPG reaction are positive, reduction of nitrate occurs in aerobic conditions but not in anaerobic conditions. The predominant fatty acids of strain ZH114T are summed feature 8 (C18:1ω7c and/or C18:1ω6c) (56.1%), C16:0 (14.6%), C18:0 (13.7%), and 11-methyl C18:1ω7c (6.9%). The polar lipids found in strain ZH114T are phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) phosphatidylethanolamine (PE) and two unidentified lipids (L1, L2). The major respiratory quinone of strain ZH114T is Q-10 and the DNA G+C content is 63.8 mol%. The 16S rRNA gene scequences indicates that strain ZH114T is most closly to the Salipiger mucescens LMG 22090Twith the highest similarity of 96.83%. On the basis of phenotypic and phylogenetic studies, strain ZH114T was considering to represent a novel species in the genus Salipiger, for which the name Salipiger nanhaiensis sp. nov.is proposed. |
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