Microbial Insights, Incorporated , 10515 Research Drive , Knoxville , Tennessee 37932 , United States.
School of Civil and Environmental Engineering , Atlanta , Georgia 30332-0512.
Environ Sci Technol. 2018 Nov 20;52(22):13410-13420. doi: 10.1021/acs.est.8b04373. Epub 2018 Nov 8.
Quantitative PCR (qPCR) targeting Dehalococcoides mccartyi ( Dhc) biomarker genes supports effective management at sites impacted with chlorinated ethenes. To establish correlations between Dhc biomarker gene abundances and ethene formation (i.e., detoxification), 859 groundwater samples representing 62 sites undergoing monitored natural attenuation or enhanced remediation were analyzed. Dhc 16S rRNA genes and the vinyl chloride (VC) reductive dehalogenase genes bvcA and vcrA were detected in 88% and 61% of samples, respectively, from wells with ethene. Dhc 16S rRNA, bvcA, vcrA, and tceA (implicated in cometabolic reductive VC dechlorination) gene abundances all positively correlated with ethene formation. Significantly greater ethene concentrations were observed when Dhc 16S rRNA gene and VC RDase gene abundances exceeded 10 and 10 copies L, respectively, and when Dhc 16S rRNA- and bvcA + vcrA-to-total bacterial 16S rRNA gene ratios exceeded 0.1%. Dhc 16S rRNA gene-to- vcrA/ bvcA ratios near unity also indicated elevated ethene; however, no increased ethene was observed in 19 wells where vcrA and/or bvcA gene copy numbers exceeded Dhc cell numbers 10- to 10 000-fold. Approximately one-third of samples with detectable ethene lacked bvcA, vcrA, and tceA, suggesting that comprehensive understanding of VC detoxification biomarkers has not been achieved. Although the current biomarker suite is incomplete, the data analysis corroborates the value of the available Dhc DNA biomarkers for prognostic and diagnostic groundwater monitoring at sites impacted with chlorinated ethenes.
定量聚合酶链反应（qPCR）针对 Dehalococcoides mccartyi（Dhc）生物标志物基因，支持对受氯代烯烃影响的地点进行有效管理。为了建立 Dhc 生物标志物基因丰度与乙烯形成（即解毒）之间的相关性，对 62 个正在进行监测的自然衰减或强化修复的地点的 859 个地下水样本进行了分析。在含有乙烯的井中，分别检测到 Dhc 16S rRNA 基因和氯乙烯（VC）还原脱卤酶基因 bvcA 和 vcrA，分别占 88%和 61%的样本。Dhc 16S rRNA、bvcA、vcrA 和 tceA（涉及共代谢还原 VC 脱氯）基因丰度均与乙烯形成呈正相关。当 Dhc 16S rRNA 基因和 VC RDase 基因丰度分别超过 10 和 10 个拷贝/L，以及 Dhc 16S rRNA 和 bvcA+vcrA 与总细菌 16S rRNA 基因的比值超过 0.1%时，观察到显著更高的乙烯浓度。Dhc 16S rRNA 基因与 vcrA/bvcA 比值接近 1 也表明乙烯升高；然而，在 19 个井中，即使 vcrA 和/或 bvcA 基因拷贝数超过 Dhc 细胞数 10-10000 倍，也没有观察到乙烯增加。约有三分之一可检测到乙烯的样本缺乏 bvcA、vcrA 和 tceA，这表明对 VC 解毒生物标志物的综合理解尚未实现。尽管当前的生物标志物套件不完整，但数据分析证实了现有的 Dhc DNA 生物标志物在受氯代烯烃影响的地点进行预测性和诊断性地下水监测的价值。
