Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea.
Department of Biotechnology, Sangmyung University, Seoul 03016, South Korea.
Ecotoxicol Environ Saf. 2021 Mar 15;211:111928. doi: 10.1016/j.ecoenv.2021.111928. Epub 2021 Jan 18.
The chloroacetanilides are among the most commonly used herbicides worldwide, which contaminate aquatic environments and affect aquatic phototrophs. Their sub-lethal toxicity has been evaluated using freshwater algae; however, the modes of cellular toxicity and levels of toxicity to marine organisms are not fully understood. In the present study, we assessed the cellular and molecular effects of chloroacetanilides on marine phototrophs using the dinoflagellate Prorocentrum minimum and the herbicide metazachlor (MZC). The MZC treatment led to a considerable reduction in cell number and pigment, and the EC of MZC was calculated to be 0.647 mg/L. The photosynthetic parameters, Fv/Fm and chlorophyll fluorescence significantly decreased with MZC exposure time in a dose-dependent manner. In addition, MZC significantly induced photosynthesis genes, including PmpsbA, PmpsaA, and PmatpB, and the antioxidant PmGST, but not PmKatG. These findings were well matched to reactive oxygen species (ROS) production in MZC-treated cells. Interestingly, we observed inflated vacuoles, undivided chloroplasts, and breakdown of thylakoid membranes in MZC-treated cells. These results support the hypothesis that MZC severely damages chloroplasts, resulting in dysfunction of the dinoflagellate photosynthesis and possibly marine phototrophs in the environment.
氯乙酰胺类除草剂是全球应用最广泛的除草剂之一，它们会污染水生环境并影响水生光养生物。已经使用淡水藻类评估了它们的亚致死毒性；然而，其对海洋生物的细胞毒性模式和毒性水平尚未完全了解。在本研究中，我们使用海洋甲藻原甲藻最小和除草剂甲草嗪（MZC）评估了氯乙酰胺类除草剂对海洋光养生物的细胞和分子影响。MZC 处理导致细胞数量和色素显著减少，并且 MZC 的 EC 计算为 0.647 mg/L。光合参数 Fv/Fm 和叶绿素荧光随 MZC 暴露时间呈剂量依赖性显著降低。此外，MZC 显著诱导了光合作用基因，包括 PmpsbA、PmpsaA 和 PmatpB，以及抗氧化基因 PmGST，但不诱导 PmKatG。这些发现与 MZC 处理细胞中的活性氧 (ROS) 产生非常吻合。有趣的是，我们观察到在 MZC 处理的细胞中出现膨胀的空泡、未分裂的叶绿体和类囊体膜破裂。这些结果支持了 MZC 严重破坏叶绿体的假说，导致甲藻光合作用功能障碍，并可能导致环境中的海洋光养生物受损。
