Environmental Engineering Post-Graduation Program, University of Blumenau, Blumenau, SC, Brazil.
Biodiversity Post-graduate Program, University of Blumenau, Blumenau, SC, Brazil.
Chemosphere. 2022 Dec;308(Pt 2):136327. doi: 10.1016/j.chemosphere.2022.136327. Epub 2022 Sep 7.
The S-triazine herbicide ametryn (AMT) is relatively low adsorbed in soils and has high solubility in water, thus believed to affect non-target aquatic organisms such as amphibians. Temperature increases can intensify the effects of herbicides, possibly increasing the susceptibility of amphibians to these compounds. The aim of this study was to evaluate the influence of temperature (25 and 32 °C) on the responses of biochemical biomarkers in bullfrog tadpoles (Lithobates catesbeianus) exposed to different concentrations of AMT (0, 10, 50 and 200 ng.L) for a period of 16 days. The antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) and the biotransformation enzyme glutathione S-transferase (GST) had their activity decreased at the highest temperature (32 °C). SOD activity was reduced at 200 ng.L and 32 °C compared to the control at the same temperature. AMT exposure also decreased the activities of alanine aminotransferase and gamma glutamyl transferase. On the other hand, the activities of acetylcholinesterase, carboxylesterase, alkaline phosphatase, levels of lipid peroxidation and protein carbonyl, as well genotoxic markers (micronucleus and nuclear abnormalities frequencies) were unchanged. The evaluation of integrated biomarker response index (IBR) indicated highest variations at the concentration of 200 ng.L at 32 °C, suggesting that the combination of high AMT concentrations and temperatures generate more pronounced negative effects to tadpoles.
三嗪类除草剂莠去津（AMT）在土壤中吸附性较低，水溶性较高，因此被认为会影响到水生无脊椎动物等非靶标生物。温度升高会加剧除草剂的影响，可能会增加两栖动物对这些化合物的敏感性。本研究旨在评估温度（25 和 32°C）对暴露于不同莠去津浓度（0、10、50 和 200ng·L）的牛蛙蝌蚪（Lithobates catesbeianus）生化生物标志物反应的影响，暴露时间为 16 天。在最高温度（32°C）下，抗氧化酶过氧化氢酶（CAT）和超氧化物歧化酶（SOD）以及生物转化酶谷胱甘肽 S-转移酶（GST）的活性降低。与相同温度下的对照相比，200ng·L 和 32°C 时 SOD 活性降低。莠去津暴露还降低了丙氨酸氨基转移酶和γ-谷氨酰转移酶的活性。另一方面，乙酰胆碱酯酶、羧酸酯酶、碱性磷酸酶的活性、脂质过氧化水平和蛋白质羰基、以及遗传毒性标志物（微核和核异常频率）没有变化。综合生物标志物反应指数（IBR）的评估表明，在 32°C 时 200ng·L 的浓度下变化最大，表明高莠去津浓度和温度的组合会对蝌蚪产生更明显的负面影响。
