Aquatic organisms are affected by both water temperature fluctuation and the waterborne pollutants such as heavy metals. In this study, we investigated the effects of water temperature and/or mercury (Hg) on antioxidant parameters (SOD, superoxide dismutase; CAT, catalase; MDA, malondialdehyde; TAOC, total antioxidant capacity), the stress proteins (HSP70, heat shock protein 70; MTs, metallothionein) and the stress hormone (COR, cortisol hormone), as well as the related genes expression of grass carp, Ctenopharyngodon idella. Fish (45.37 ± 3.58 g) were acclimated to 15, 20, 25, 30 or 35°C and co‐exposed to 0.0 or 0.039 mg/L HgCl₂ for 4 weeks in triplicates. Three‐way ANOVA revealed that all variables were significantly affected by water temperature, Hg exposure, exposure time and their interactions. The activities of antioxidant enzymes increased significantly by increasing water temperature up to 30°C, after which they decreased significantly at 35°C. The levels of HSP70 and MTs increased with increasing water temperature up to 35°C, but Hg‐exposed fish showed lower levels of two stress proteins as compared to Hg‐free fish groups. Additional, the cortisol content was not positively correlated with temperature. Our data provide evidences that warmer temperatures can potentiate Hg toxicity. Due to the complex mechanism of the toxicity of temperature coupled pollutants on aquatic organisms, more detailed experiments in laboratory need to be performed before these parameters are used as special biomarkers for monitoring aquatic environment.

中文翻译：

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温度和汞暴露对淡水鱼类Ctenopharyngodon idella胁迫相关反应的交互作用

水生生物既受水温波动影响，也受水污染物（如重金属）的影响。在这项研究中，我们研究了水温和/或汞（Hg）对抗氧化剂参数（SOD，超氧化物歧化酶； CAT，过氧化氢酶； MDA，丙二醛； TAOC，总抗氧化剂能力），应激蛋白（HSP70，热休克）的影响蛋白70； MTs，金属硫蛋白）和应激激素（COR，皮质醇激素），以及草鱼Ctenopharyngodon idella的相关基因表达。将鱼（45.37±3.58 g）适应15、20、25、30或35°C，并共同暴露于0.0或0.039 mg / L HgCl ₂一式三份，共4周。三因素方差分析显示，所有变量均受水温，汞暴露，暴露时间及其相互作用的显着影响。通过将水温升高到30°C，抗氧化酶的活性显着增加，然后在35°C时，抗氧化酶的活性显着下降。HSP70和MT的含量随水温升高至35°C而增加，但是与无汞的鱼类相比，接触汞的鱼类的两种应激蛋白水平较低。另外，皮质醇含量与温度没有正相关。我们的数据提供了证据，表明温度升高可以增强汞的毒性。由于温度耦合污染物对水生生物毒性的复杂机制，