Publications (4)7.85 Total impact
-
Article: Diversity and high nitrogenase activity of endophytic diazotrophs isolated from Oryza rufipogon Griff.
[show abstract] [hide abstract]
ABSTRACT: Diversity and nitrogenase activity of endophytic diazotrophs colonized in the wild rice Oryza rufipogon Griff grown in Boluo, Huilai County in Guangdong Province and Lingshui County in Hainan Province were studied. Thirty-seven isolates obtained from Oryza rufipogon were identified as putative endophytic nitrogen-fixing bacteria by ARA (acetylene reduction assay) test and further confirmed by PCR amplification of nifH gene fragments. All obtained strains have ARA activity and the same sized nifH gene fragments. Above the similarity level of 80%, the obtained isolates were assigned as Group I to VIII by the clustering of IS-PCR fingerprints. The SDS-PAGE whole-cell protein patterns were similar to those of IS-PCR fingerprints. Components and contents of fatty acid methyl esters (FAMEs) were used to differentiate the representative strains (Ls13, Ls8, BL1, BL12, HL6, Ls4) from Group I to Group VI. The six representative strains showed significant difference in contents and components of cellular fatty acid methyl ester. 16S rDNA sequencing analysis showed that strains of Group I to VII were located in Enterobacteraceae (γ-proteobacteria). Strains of Group I and Group II were closely related to Klebsiella sp.; Strain Ls8 of Group II was a little far away from the genus of Pantoea (homology level 96% with Pantoea agglomerans), which may represent a new species or genus in Enterobacteraceae; Strains of Groups IV and V belonged to different Enterobacter sp.; Strain Ls4 and Ls 9 representing Group VI were close to Citrobacter amalonaticus with 98% sequence similarity; Strain Ls15 of Group VII showed 98% sequence identity with Pantoea sp.; Strains of Group VIII were assigned to the genus Ideonella (β-proteobacteria). Based on the above results, endophytic diazotrophs isolated from O. rufipogon showed great diversity and some diazotrophs showed high nitrogenase activity with 42.52 μmol/mL·h C2H4. Inoculation to rice tests indicated that the isolated endophytic diazotrophs significantly promoted the rice growth.Chinese Science Bulletin 04/2012; 54(16):2839-2848. · 1.32 Impact Factor -
Article: Safety assessment of the source water within the Pearl River Delta on the aspect of organochlorine pesticides contamination.
[show abstract] [hide abstract]
ABSTRACT: The safety of source water is a noticeable problem in the Pearl River Delta, one of the densely populated areas in China. In this study, 20 individual organochlorine pesticides (OCPs) were investigated in 15 water sources within this area using gas chromatography-electron capture detector, and the hazard risks to human health were assessed in terms of individual OCPs based on daily water consumption according to the standard recommended by the United States Environmental Protection Agency. Results showed that the total OCP concentrations ranged from 2.42 ng l(-1) to 39.52 ng l(-1) during the years 2008 and 2009. The hazard ratios based on both non-cancer and cancer benchmarks were less than 1 for all the water samples, which indicated that individual OCPs posed no risk to human health. However, the risks caused by the combined toxicity of total OCPs in this area should not be ignored.Journal of Environmental Monitoring 09/2010; 12(9):1666-77. · 1.99 Impact Factor -
Article: Brachybacterium zhongshanense sp. nov., a cellulose-decomposing bacterium from sediment along the Qijiang River, Zhongshan City, China.
[show abstract] [hide abstract]
ABSTRACT: A cellulose-decomposing bacterium, strain JBT, was isolated from sediments along the Qijiang River, Zhongshan City, China. Results of morphological, biochemical and chemotaxonomic characterization and 16S rRNA gene sequence analysis revealed that strain JBT belonged to the genus Brachybacterium. Insertion sequence-PCR fingerprinting patterns, DNA base ratio analysis and DNA-DNA hybridization data showed that strain JBT differed from recognized species of the genus Brachybacterium. Based on polyphasic analysis, strain JBT represents a novel species of the genus Brachybacterium, for which the name Brachybacterium zhongshanense sp. nov. is proposed. The type strain is JBT (=LMG 23926T=CGMCC 1.6508T=DSM 18832T).International journal of systematic and evolutionary microbiology 12/2007; 57(Pt 11):2519-24. · 2.27 Impact Factor -
Article: Azospirillum melinis sp. nov., a group of diazotrophs isolated from tropical molasses grass.
[show abstract] [hide abstract]
ABSTRACT: Fifteen bacterial strains isolated from molasses grass (Melinis minutiflora Beauv.) were identified as nitrogen-fixers by using the acetylene-reduction assay and PCR amplification of nifH gene fragments. These strains were classified as a unique group by insertion sequence-PCR fingerprinting, SDS-PAGE protein patterns, DNA-DNA hybridization, 16S rRNA gene sequencing and morphological characterization. Phylogenetic analysis of the 16S rRNA gene indicated that these diazotrophic strains belonged to the genus Azospirillum and were closely related to Azospirillum lipoferum (with 97.5 % similarity). In all the analyses, including in addition phenotypic characterization using Biolog MicroPlates and comparison of cellular fatty acids, this novel group was found to be different from the most closely related species, Azospirillum lipoferum. Based on these data, a novel species, Azospirillum melinis sp. nov., is proposed for these endophytic diazotrophs of M. minutiflora, with TMCY 0552(T) (=CCBAU 5106001(T) = LMG 23364(T) = CGMCC 1.5340(T)) as the type strain.International journal of systematic and evolutionary microbiology 07/2006; 56(Pt 6):1263-71. · 2.27 Impact Factor
