Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan.
Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
Chemosphere. 2024 Aug;361:142423. doi: 10.1016/j.chemosphere.2024.142423. Epub 2024 Jun 1.
This study investigates the effects of glyphosate-based herbicide (GLY) and pure emamectin benzoate (EB) insecticide on the brackish copepod Pseudodiaptomus annandalei. The 96h median lethal concentration (96 h LC50) was higher in the GLY exposure (male: 3420.96 ± 394.67 μg/L; female: 3093.46 ± 240.67 μg/L) than in the EB (male: 79.10 ± 7.30 μg/L; female: 6.38 ± 0.72 μg/L). Based on the result of 96h LC50, we further examined the effects of GLY and EB exposures at sub-lethal concentrations on the naupliar production of P. annandalei. Subsequently, a multigenerational experiment was conducted to assess the long-term impact of GLY and EB at concentrations 375 μg/L, and 0.025 μg/L respectively determined by sub-lethal exposure testing. During four consecutive generations, population growth, clutch size, prosome length and width, and sex ratio were measured. The copepods exposed to GLY and EB showed lower population growth but higher clutch size than the control group in most generations. Gene expression analysis indicated that GLY and EB exposures resulted in the downregulation of reproduction-related (vitellogenin) and growth-related (myosin heavy chain) genes, whereas a stress-related gene (heat shock protein 70) was upregulated after multigenerational exposure. The results of the toxicity test after post-multigenerational exposure indicated that the long-term GLY-exposed P. annandalei displayed greater vulnerability towards GLY toxicity compared to newly-exposed individuals. Whereas, the tolerance of EB was significantly higher in the long-term exposed copepod than in newly-exposed individuals. This suggests that P. annandalei might have greater adaptability towards EB toxicity than towards GLY toxicity. This study reports for the first time the impacts of common pesticides on the copepod P. annandalei, which have implications for environmental risk assessment and contributes to a better understanding of copepod physiological responses towards pesticide contaminations.
本研究调查了草甘膦基除草剂（GLY）和纯甲氨基阿维菌素苯甲酸盐（EB）杀虫剂对低盐度桡足类伪镖水蚤（Pseudodiaptomus annandalei）的影响。96 小时半致死浓度（96 h LC50）在 GLY 暴露组中较高（雄性：3420.96±394.67μg/L；雌性：3093.46±240.67μg/L），而在 EB 暴露组中较低（雄性：79.10±7.30μg/L；雌性：6.38±0.72μg/L）。基于 96 h LC50 的结果，我们进一步研究了亚致死浓度下 GLY 和 EB 暴露对伪镖水蚤幼体生产的影响。随后，进行了多代实验，以评估浓度分别为 375μg/L 和 0.025μg/L 的 GLY 和 EB 的长期影响，这两个浓度是通过亚致死暴露测试确定的。在连续四代的过程中，测量了种群增长、卵囊大小、前体长度和宽度以及性别比。与对照组相比，暴露于 GLY 和 EB 的桡足类动物在大多数世代中的种群增长较低，但卵囊大小较高。基因表达分析表明，GLY 和 EB 暴露导致与繁殖相关（卵黄蛋白原）和生长相关（肌球蛋白重链）的基因下调，而多代暴露后应激相关基因（热休克蛋白 70）上调。多代暴露后毒性测试的结果表明，与新暴露个体相比，长期暴露于 GLY 的伪镖水蚤对 GLY 毒性的敏感性更高。而长期暴露的桡足类动物对 EB 的耐受性明显高于新暴露的个体。这表明，与 GLY 毒性相比，P. annandalei 可能对 EB 毒性具有更大的适应性。本研究首次报道了常见农药对桡足类 P. annandalei 的影响，这对环境风险评估具有重要意义，并有助于更好地了解桡足类动物对农药污染的生理反应。
