Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand; Gut Biology and Microbiota Research Unit, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand; Coastal Oceanography and Climate Change Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
Aquat Toxicol. 2020 Jul;224:105517. doi: 10.1016/j.aquatox.2020.105517. Epub 2020 May 16.
Temperature affects physiological processes in organisms and the toxicity of chemicals. The widespread industrial use of ZnO causes contamination in aquatic ecosystems. This study aimed to investigate the chronic toxicity of ZnO at different temperatures using Daphnia magna as a model organism. The chronic toxicity of five different concentrations of ZnO was assessed at 23 °C and 28 °C. The results showed that higher concentrations of ZnO inhibited growth, production of first clutch eggs and juvenile accumulation at both 23 °C and 28 °C. Growth rate, numbers of first clutch eggs and juvenile accumulation were lower at 28 °C than at 23 °C. We also observed the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) activity. At higher concentrations of ZnO, oxidative stress was induced leading to increase MDA level and decrease SOD activity at 28 °C. These findings indicated that high temperature and high concentration of ZnO inhibited the activity of enzymatic proteins. Nonetheless, among all treatments, the accumulation of zinc in D. magna was not significantly different. Our results suggested that both ZnO and higher temperature induced oxidative stress in D. magna. As a result, MDA concentration increased, SOD activity changed and the growth and reproduction of D. magna was adversely affected.
温度会影响生物体的生理过程和化学物质的毒性。氧化锌在工业上的广泛应用导致了水生生态系统的污染。本研究旨在以大型溞（Daphnia magna）为模式生物，研究不同温度下氧化锌的慢性毒性。在 23°C 和 28°C 下，评估了五种不同浓度的氧化锌的慢性毒性。结果表明，较高浓度的氧化锌在 23°C 和 28°C 下均抑制了生长、第一产卵量和幼体积累。28°C 时的生长速率、第一产卵量和幼体积累均低于 23°C。我们还观察了丙二醛（MDA）和超氧化物歧化酶（SOD）活性的水平。在较高浓度的氧化锌下，会诱导氧化应激，导致 28°C 时 MDA 水平升高和 SOD 活性降低。这些发现表明，高温和高浓度的氧化锌抑制了酶蛋白的活性。尽管如此，在所有处理中，大型溞体内锌的积累并没有显著差异。我们的研究结果表明，氧化锌和较高温度都会在大型溞体内诱导氧化应激。因此，MDA 浓度增加，SOD 活性改变，大型溞的生长和繁殖受到不利影响。
