Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou 510631, Guangdong, China.
Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou 510631, Guangdong, China.
Ecotoxicol Environ Saf. 2014 Feb;100:294-302. doi: 10.1016/j.ecoenv.2013.08.021. Epub 2013 Sep 26.
In environmental studies, some biological responses, known as biomarkers, have been used as a powerful bioassay tool for more than four decades. Disparity between enzyme activity and mRNA abundance leads to correlation equivocality, which makes the application of biomarkers for environmental risk assessment more complicated. This study investigates this disparity in the case of catalase when used as a biomarker for detecting ecotoxicity induced by antibiotics in aquatic ecosystems. In particular, dose-responses for catalase activity and mRNA expression abundance were investigated in Euplotes vannus which were exposed to graded doses of nitrofurazone for several discrete durations, and dose-response models were developed to characterize the dose-response dynamics. Significant differences were found in both catalase activity and mRNA expression abundance among the E. vannus treated with nitrofurazone. Catalase activity showed a hormetic-like effect in terms of dose-response, characterized by a biphasic relationship which was more clearly evident after a longer exposure period, while mRNA expression abundance increased linearly with the exposure duration. Additionally, the correlation between catalase activity and mRNA expression abundance reversed along with the duration of exposure to nitrofurazone. Taken together, our results demonstrate that catalase mRNA expression offers a more straightforward dose-response model than enzyme activity. Our findings suggest that both catalase enzyme activity and mRNA expression abundance can be used jointly as bioassay tools for detecting ecotoxicity induced by nitrofurazone in aquatic ecosystems.
在环境研究中，一些生物反应，被称为生物标志物，已经被用作一种强大的生物测定工具超过四十年。酶活性和 mRNA 丰度之间的差异导致相关性的不确定性，这使得生物标志物在环境风险评估中的应用更加复杂。本研究以水生生态系统中抗生素诱导的生态毒性检测用的过氧化氢酶为例，调查了这种差异。具体来说，我们研究了在不同的硝基呋喃酮剂量下暴露于不同时间的钟形四膜虫中过氧化氢酶活性和 mRNA 表达丰度的剂量反应，并建立了剂量反应模型来描述剂量反应动力学。用硝基呋喃酮处理的钟形四膜虫中，过氧化氢酶活性和 mRNA 表达丰度均存在显著差异。过氧化氢酶活性的剂量反应呈现出一种激素样的效应，表现为双相关系，这种关系在更长的暴露时间后更为明显，而 mRNA 表达丰度则随暴露时间线性增加。此外，随着暴露于硝基呋喃酮的时间的延长，过氧化氢酶活性和 mRNA 表达丰度之间的相关性发生了逆转。总之，我们的研究结果表明，过氧化氢酶 mRNA 表达提供了比酶活性更简单的剂量反应模型。我们的研究结果表明，过氧化氢酶酶活性和 mRNA 表达丰度都可以作为生物测定工具，联合用于检测水生生态系统中由硝基呋喃酮引起的生态毒性。
