Li Zheng

Biodiversity and degradation potential of oil-degrading bacteria isolated from deep-sea sediments of South Mid-Atlantic Ridge

The indigenous oil-degrading bacterial consortia MARA and MARB were enriched from the deep-sea sediments of South Mid-Atlantic Ridge (MAR) with crude oil as sole carbon and energy sources. Biodiversity and community analyses showed that members of α-Proteobacteria were the key players in consortium MARA, whereas those of γ-Proteobacteria were the key players in consortium MARB, which were studied by MiSeq sequencing method. Gravimetric method estimated the oil degradation rates of MARA and MARB to be 63.4% and 85.8%, respectively, after 20d. Eleven cultivable oil degraders with different morphologies were isolated. These strains were identified as Alcanivorax, Bacillus, Dietzia, Erythrobacter, Marinobacter, Nitratireductor, and Oceanicola based on 16S rRNA gene sequences. Three strains belonging to Dietzia exhibited the highest oil degradation capability. Results indicated that the intrinsic biodegradation capacity of oil contaminants by indigenous microbial communities exists in South MAR sediments.

Genome Sequence of the Pyrene- and Fluoranthene-Degrading Bacterium Cycloclasticus sp. Strain PY97M.

ABSTRACT Cycloclasticus sp. strain PY97M was isolated from a phenanthrene-degrading consortium, enriched from Yellow Sea sediment of China. Here, we present the draft genome sequence of strain PY97M, which contains 2,359,509 bp with a G+C content of 41.92% and contains 2, 264 protein-coding genes and 40 tRNAs.

Marinobacter aromaticivorans sp. nov., a polycyclic aromatic hydrocarbon-degrading bacterium isolated from sea sediment.

A rod-shaped, Gram-stain-negative, slightly halotolerant bacterium, designated strain D15-8PT, was isolated from a sediment sample from the South China Sea. The strain could grow in NaCl concentrations ranging from 0.5 % to 10 % (w/v) (optimum 0.5-1.5 %), and could be cultivated at 10-40 °C (optimum 25 °C) and pH 5.5-9.5 (optimum pH 7.0-8.0). The strain was positive for catalase, oxidase, and hydrolysis of Tween 80, but negative for hydrolysis of DNA and gelatin, nitrite reduction, indole production, Voges-Proskauer reaction, and methyl red test. Strain D15-8PT could biodegrade naphthalene, phenanthrene, and anthracene. The major respiratory quinone was Q-9. The main cellular fatty acids were C12 : 0 (11.5 %), C14 : 0 3-methyl (22.0 %), C16 : 0 (19.2 %), C16 : 1ω9c (22.9 %), and C18 : 1ω9c (6.7 %). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminophospholipid and an unidentified phospholipid. The DNA G+C content was 56.8 mol%. Phylogenetic analyses based on 16S rRNA genes showed that strain D15-8PT was most closely related to Marinobacter maritimus JCM 12521T (98.5 % 16S rRNA gene sequence similarity), Marinobacter antarcticus CGMCC 1.10835T (98.1 %), Marinobacter lipolyticus DSM 15157T (97.1 %), and Marinobacter guineae CECT 7243T (97.0 %). Results of the gyrB gene analysis and DNA-DNA hybridization were both less than the cut-off values (90 % for gyrB gene sequence similarity and 70 % for DNA-DNA hybridization). On the basis of this taxonomic study using a polyphasic approach, strain D15-8PT represents a novel species of the genus Marinobacter, for which the name Marinobacter aromaticivorans sp. nov. is proposed. The type strain is D15-8PT ( = CGMCC 1.11015T = KCTC 23781T).

Genome Sequence of the Polycyclic Aromatic Hydrocarbon-Degrading Bacterium Strain Marinobacter nanhaiticus D15-8WT.

ABSTRACT Marinobacter nanhaiticus strain D15-8WT was isolated from a phenanthrene-degrading consortium, enriched from sediment of the South China Sea. Here, we present the draft genome of strain D15-8WT, which contains 5,358,309 bp with a G+C content of 58.53% and contains 4,829 protein-coding genes and 47 tRNA genes.

Draft Genome Sequence of Rhodobacteraceae Strain PD-2, an Algicidal Bacterium with a Quorum-Sensing System, Isolated from the Marine Microalga Prorocentrum donghaiense

ABSTRACT Rhodobacteraceae strain PD-2 was isolated from the marine microalga Prorocentrum donghaiense. It has algicidal activity toward its host and could produce N-acylhomoserine lactone signals. Here, we present the draft genome of strain PD-2, which contains 5,227,214 bp with an average GC content of 66.19%. There were 4,864 encoding gene sequences and two clusters of luxI and luxR homologues identified.

Genome Sequence of the Petroleum Hydrocarbon-Degrading Bacterium Alcanivorax sp. Strain 97CO-5

ABSTRACT Alcanivorax sp. strain 97CO-5 was isolated from a crude-oil-degrading consortium, enriched from Yellow Sea sediment of China. Here, we present the draft genome of strain 97CO-5, which comprises 3,251,558 bp with a G+C content of 54.54% and contains 2,962 protein-coding genes and 42 tRNAs.

Bacterial Interaction in the Biodegradation of High Molecular Weight Polycyclic Aromatic Hydrocarbons: Bacterial Interaction in the Biodegradation of High Molecular Weight Polycyclic Aromatic Hydrocarbons

해양 미생물 사이의 고분자 다환 방향족 탄화수소(High molecular weight - polycyclic aromatic hydrocarbons, HMW.PAHs) 분해 과정 중의 상호 작용을 연구하기 위하여, 시너지 효과를 가진 세균 군집을 선별하고 HMW-PAHs를 분해할 수 있는 Cycloclasticus속 세균인 Cycloclasticus sp.PY97M 하나와 4주의 기타 속 세균으...

Determination of Lead Species in Algae by Capillary Electrophoresis-Inductively Coupled Plasma-Mass Spectrometry

A method of capillary electrophoresis (CE) coupled with inductively coupled plasma-mass spectrometry (ICP-MS) was established to determine lead ion [Pb(II)], trimethyl lead (TML), and triethyl lead (TEL). An extraction technology for lead with different species in algae was proposed and optimized for qualitative and quantitative analyses. Experimental results showed that these three lead compounds could be effectively separated within 20 min by CE-ICP-MS in a buffer solution of 70 mM H3BO3 and 17.5 M Na2B4O7 (pH 8.9). This method had good reproducibility for migration time (relative standard deviation (RSD) < 4%) and peak area (RSD < 5%). On the basis of this, the three lead compounds were detected in the linearity range of 10–200 μg L−1 with the correlation coefficient over 0.90. The detection limits for Pb(II), TML and TEL (S/N = 3, Pb) were 0.091, 0.023 and 0.030 μg L−1, respectively. The fractional extraction rate of Pb exceeded 80%, and the recoveries of Pb(II), TML, and TEL in algae samples were 103.6%, 95.7% and 90.6%, respectively. The detection results of lead content in laver and kelp samples showed that Pb in algae mainly existed in the form of Pb(II). Given its simplicity, high efficiency, and low sample consumption, the method could provide technical support for the quality control of marine algae and other marine products.

Determination of trace metals and analysis of arsenic species in tropical marine fishes from Spratly islands

Trace metal contents in 38 species of tropical marine fishes harvested from the Spratly islands of China were determined by microwave digestion and inductively coupled plasma mass spectrometry analysis. Arsenic species were determined by high-performance liquid chromatography and inductively coupled plasma mass spectrometry analysis. The average levels of Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Pb, and U in the fish samples were 1.683, 0.350, 0.367, 2.954, 36.615, 0.087, 0.319, 1.566, 21.946, 20.845, 2.526, 3.583, 0.225, 0.140, and 0.061mg·kg-1, respectively; Fe, Zn, and As were found at high concentrations. The trace metals exhibited significant positive correlation between each other, with r value of 0.610-0.852. Further analysis indicated that AsB (8.560-31.020mg·kg-1) was the dominant arsenic species in the fish samples and accounted for 31.48% to 47.24% of the total arsenic. As(III) and As(V) were detected at low concentrations, indicating minimal arsenic toxicity.

Geochemical characteristics of rare earth elements in the surface sediments from the Spratly Islands of China

The geochemistry of rare earth elements (REE) in surface sediment from Cuarteron reef (N1), Johnson reef (N2), Hugh reef (N3), Gaven reef (N4), Fiery cross reef (N5), and Subi reef (N6) were firstly studied. The total REE abundance (∑REE) varied from 2.244μg·g-1 to 21.661μg·g-1, with an average of 4.667μg·g-1. The LREE/HREE was from 2.747 to 9.869, with an average of 3.687, which indicated that the light REE was evidently enriched. Fractionation was observed between LREE and HREE. Gd with a negative anomaly was also detected in all of the stations. The negative anomalies of δEu from 0.11 to 0.25, with an average of 0.22, and the positive anomalies of δCe from 1.38 to 3.86, with an average of 1.63. The REE individual correlation values with Ca, Mn, Mg, Sr were rCa=-0.05, rMn=0.26, rMg=-0.14, and rSr=0.08.