Jiang Bo, Li Guanghe, Xing Yi, Zhang Dayi, Jia Jianli, Cui Zhisong, Luan Xiao, Tang Hui
School of Energy and Environmental Engineering, University of Science & Technology Beijing, Beijing, 100083, People's Republic of China; School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China.
School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China.
Chemosphere. 2017 Oct;184:384-392. doi: 10.1016/j.chemosphere.2017.05.159. Epub 2017 Jun 7.
Whole-cell bioreporters have emerged as promising tools for genotoxicity evaluation, due to their rapidity, cost-effectiveness, sensitivity and selectivity. In this study, a method for detecting genotoxicity in environmental samples was developed using the bioluminescent whole-cell bioreporter Escherichia coli recA::luxCDABE. To further test its performance in a real world scenario, the E. coli bioreporter was applied in two cases: i) soil samples collected from chromium(VI) contaminated sites; ii) crude oil contaminated seawater collected after the Jiaozhou Bay oil spill which occurred in 2013. The chromium(VI) contaminated soils were pretreated by water extraction, and directly exposed to the bioreporter in two phases: aqueous soil extraction (water phase) and soil supernatant (solid phase). The results indicated that both extractable and soil particle fixed chromium(VI) were bioavailable to the bioreporter, and the solid-phase contact bioreporter assay provided a more precise evaluation of soil genotoxicity. For crude oil contaminated seawater, the response of the bioreporter clearly illustrated the spatial and time change in genotoxicity surrounding the spill site, suggesting that the crude oil degradation process decreased the genotoxic risk to ecosystem. In addition, the performance of the bioreporter was simulated by a modified cross-regulation gene expression model, which quantitatively described the DNA damage response of the E. coli bioreporter. Accordingly, the bioluminescent response of the bioreporter was calculated as the mitomycin C equivalent, enabling quantitative comparison of genotoxicities between different environmental samples. This bioreporter assay provides a rapid and sensitive screening tool for direct genotoxicity assessment of environmental samples.
由于全细胞生物报告基因具有快速、成本效益高、灵敏度高和选择性强等特点，已成为遗传毒性评估的有前途的工具。在本研究中，开发了一种使用生物发光全细胞生物报告基因大肠杆菌recA::luxCDABE检测环境样品中遗传毒性的方法。为了在实际场景中进一步测试其性能，将大肠杆菌生物报告基因应用于两个案例：i）从六价铬污染场地采集的土壤样品；ii）2,013年胶州湾溢油事件后收集的原油污染海水。对六价铬污染的土壤进行水萃取预处理，并分两个阶段直接暴露于生物报告基因：水土萃取液（水相）和土壤上清液（固相）。结果表明，可萃取的和土壤颗粒固定的六价铬对生物报告基因都是生物可利用的，固相接触生物报告基因检测法对土壤遗传毒性的评估更为精确。对于原油污染海水，生物报告基因的响应清楚地说明了溢油现场周围遗传毒性的空间和时间变化，表明原油降解过程降低了对生态系统的遗传毒性风险。此外，通过改进的交叉调节基因表达模型模拟了生物报告基因的性能，该模型定量描述了大肠杆菌生物报告基因的DNA损伤反应。因此，将生物报告基因的生物发光响应计算为丝裂霉素C当量，从而能够对不同环境样品之间的遗传毒性进行定量比较。这种生物报告基因检测法为环境样品的直接遗传毒性评估提供了一种快速、灵敏的筛选工具。
