Isolation and Characterization of "Dehalococcoides" sp Strain MB, Which Dechlorinates Tetrachloroethene to trans-1,2-Dichloroethene
Isolation and Characterization of "Dehalococcoides" sp Strain MB, Which Dechlorinates Tetrachloroethene to trans-1,2-Dichloroethene
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DOI：
10.1128/aem.00767-09
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发表时间：
2009-09-15
影响因子：
4.4
通讯作者：
He, Jianzhong
中科院分区：
文献类型：
--
作者：
Cheng, Dan;He, Jianzhong
为了了解反式-1，2-二氯乙烯(Trans-1，2-DCE)产生过程中所涉及的微生物，对纯培养的脱卤球菌属进行了研究。菌株MB是从环境沉积物中分离得到的。与目前已知的四氯乙烯(PCE)或三氯乙烯(TCE)脱氯不同，纯培养物脱氯产生的主要产物是顺式二氯乙烯，即脱卤球菌属。菌株MB以7.3(+/-0.4)：1的比例将PCE还原为反式DCE和顺式DCE。在厌氧呼吸过程中，它以H-2为唯一电子供体，PCE或TCE为电子受体。菌株MB是一种盘状、不能移动的细菌。在原子力显微镜下，细胞呈单个或成对出现，直径为1.0微米，深度接近150 nm。纯度经培养和16S rRNA基因分析证实，并通过基于还原脱卤酶(RDase)基因的实时定量聚合酶链式反应进一步证实。虽然MB菌株的16S rRNA基因序列与产乙烯嗜盐球菌195株有100%的同源性，但这两株菌株具有不同的脱氯途径。基因芯片分析表明，菌株195中存在的10个可能的RDase基因在菌株MB中也被检测到。菌株MB的成功培养表明，在氯乙烯污染的场所，生物过程可能对反式DCE的产生有重要贡献。这也加强了我们对这种不寻常的微生物群--脱卤球菌属物种的进化的理解。
In an attempt to understand the microorganisms involved in the generation of trans-1,2-dichloroethene (trans-DCE), pure-culture "Dehalococcoides" sp. strain MB was isolated from environmental sediments. In contrast to currently known tetrachloroethene (PCE)- or trichloroethene (TCE)-dechlorinating pure cultures, which generate cis-DCE as the predominant product, Dehalococcoides sp. strain MB reductively dechlorinates PCE to trans-DCE and cis-DCE at a ratio of 7.3 (+/- 0.4):1. It utilizes H-2 as the sole electron donor and PCE or TCE as the electron acceptor during anaerobic respiration. Strain MB is a disc-shaped, nonmotile bacterium. Under an atomic force microscope, the cells appear singly or in pairs and are 1.0 mu m in diameter and similar to 150 nm in depth. The purity was confirmed by culture-based approaches and 16S rRNA gene-based analysis and was corroborated further by putative reductive dehalogenase (RDase) gene-based, quantitative real-time PCR. Although strain MB shares 100% 16S rRNA gene sequence identity with Dehalococcoides ethenogenes strain 195, these two strains possess different dechlorinating pathways. Microarray analysis revealed that 10 putative RDase genes present in strain 195 were also detected in strain MB. Successful cultivation of strain MB indicates that the biotic process could contribute significantly to the generation of trans-DCE in chloroethene-contaminated sites. It also enhances our understanding of the evolution of this unusual microbial group, Dehalococcoides species.