Enantioselectivity tuning of chiral herbicide dichlorprop by copper: roles of reactive oxygen species.
Enantioselectivity tuning of chiral herbicide dichlorprop by copper: roles of reactive oxygen species.
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DOI：
10.1021/es2003793
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发表时间：
2011-05
影响因子：
11.4
通讯作者：
Yuezhong Wen;Hui Chen;Chensi Shen;Mei-rong Zhao;Weiping Liu
中科院分区：
文献类型：
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作者：
Yuezhong Wen;Hui Chen;Chensi Shen;Mei-rong Zhao;Weiping Liu
活性氧（ROS）被认为是细胞毒性的关键因素。然而，人们对农药、重金属和活性氧之间的对映选择性毒性之间的相互影响知之甚少。为了解开这个谜团，研究了铜（Cu）对手性农药二氯丙酸（DCPP）对斜生栅藻的对映选择性生态毒性的影响。结果表明，DCPP 和 Cu 的单独或组合存在都会导致 ROS 突然增加。这反过来又刺激抗氧化防御反应，损害亚细胞结构和生理功能，最终导致细胞生长抑制。在没有 Cu 的情况下，接触除草活性 (R)-对映体后 ROS 的产生高于 (S)-对映体，表明倾向于 (R)-对映体诱导产生 ROS。当 DCPP 和 Cu 同时添加到藻类中时，观察到 (R)-DCPP 优先诱导 ROS 的产生。然而，当 DCPP 在添加到藻类溶液中之前与 Cu 混合 24 小时时，对映选择性诱导的 ROS 产生被逆转。还发现斜生栅藻中ROS的产生、抗氧化反应和生长抑制率均优先诱导(R)-对映体。这些发现表明，ROS 在化学污染物毒性中发挥主要作用，污染物之间的相互作用可以调节手性除草剂的对映选择性，这一点应在未来的风险评估中考虑。
Reactive oxygen species (ROS) are considered to be the key players in cell toxicity. However, cross talk between the enantioselective toxicity of pesticides, heavy metals, and ROS is poorly understood. To decipher the puzzle, the effects of copper (Cu) on the enantioselective ecotoxicity of the chiral pesticide dichlorprop (DCPP) to Scenedesmus obliquus were investigated. The results showed that the presence of DCPP and Cu, both individually and in combination, caused a sudden increase of ROS. This in turn stimulated the response of antioxidant defenses, impaired subcellular structure and physiological function, and finally resulted in cell growth inhibition. In the absence of Cu, ROS production after exposure to the herbicidally active (R)-enantiomer was higher than that of the (S)-enantiomer, suggesting a preference for an (R)-enantiomer-induced production of ROS. When DCPP and Cu were both added to algae simultaneously, (R)-DCPP preferentially induced production of ROS was observed. However, the enantioselective induced production of ROS was reversed when DCPP was mixed with Cu for 24 h prior to addition to the algae solution. It was also found that the generation of ROS, antioxidant response, and growth inhibition rate in Scenedesmus obliquus were all (R)-enantiomer preferentially induced. These findings implied that ROS play a primary role in chemical contaminant toxicity, and interactions between contaminants can tune the enantioselectivity of chiral herbicides, which should be considered in future risk assessment.