Department of Civil Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
Appl Environ Microbiol. 2012 Jan;78(2):393-401. doi: 10.1128/AEM.06510-11. Epub 2011 Nov 18.
The phylum Chloroflexi contains several isolated bacteria that have been found to respire a diverse array of halogenated anthropogenic chemicals. The distribution and role of these Chloroflexi in uncontaminated terrestrial environments, where abundant natural organohalogens could function as potential electron acceptors, have not been studied. Soil samples (116 total, including 6 sectioned cores) from a range of uncontaminated sites were analyzed for the number of Dehalococcoides-like Chloroflexi 16S rRNA genes present. Dehalococcoides-like Chloroflexi populations were detected in all but 13 samples. The concentrations of organochlorine ([organochlorine]), inorganic chloride, and total organic carbon (TOC) were obtained for 67 soil core sections. The number of Dehalococcoides-like Chloroflexi 16S rRNA genes positively correlated with [organochlorine]/TOC while the number of Bacteria 16S rRNA genes did not. Dehalococcoides-like Chloroflexi were also observed to increase in number with a concomitant accumulation of chloride when cultured with an enzymatically produced mixture of organochlorines. This research provides evidence that organohalide-respiring Chloroflexi are widely distributed as part of uncontaminated terrestrial ecosystems, they are correlated with the fraction of TOC present as organochlorines, and they increase in abundance while dechlorinating organochlorines. These findings suggest that organohalide-respiring Chloroflexi may play an integral role in the biogeochemical chlorine cycle.
绿屈挠菌门包含几种已被发现能呼吸多种卤代人为化学品的分离细菌。这些绿屈挠菌在未受污染的陆地环境中的分布和作用，在这些环境中，丰富的天然有机卤化物可以作为潜在的电子受体，尚未得到研究。分析了一系列未受污染地点的土壤样本（共 116 个样本，包括 6 个分段核心），以确定存在的 Dehalococcoides 样绿屈挠菌 16S rRNA 基因的数量。除了 13 个样本外，所有样本中都检测到了 Dehalococcoides 样绿屈挠菌。获得了 67 个土壤核心部分的有机氯（[有机氯]）、无机氯和总有机碳（TOC）的浓度。Dehalococcoides 样绿屈挠菌 16S rRNA 基因的数量与[有机氯]/TOC 呈正相关，而细菌 16S rRNA 基因的数量则没有。当用酶促产生的有机氯混合物培养时，也观察到 Dehalococcoides 样绿屈挠菌的数量随着氯化物的同时积累而增加。这项研究提供了证据，表明有机卤化物呼吸绿屈挠菌作为未受污染陆地生态系统的一部分广泛分布，它们与以有机氯形式存在的 TOC 分数有关，并且在脱卤有机氯时丰度增加。这些发现表明，有机卤化物呼吸绿屈挠菌可能在生物地球化学氯循环中发挥重要作用。
