Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea.
Department of Environmental Marine Sciences, College of Science and Technology, Hanyang University, Ansan 426-791, South Korea.
Aquat Toxicol. 2014 Jul;152:308-17. doi: 10.1016/j.aquatox.2014.04.027. Epub 2014 May 9.
In this study, we investigated the effects of the water-accommodated fraction (WAF) of crude oil on the development and reproduction of the intertidal copepod Tigriopus japonicus through life-cycle experiments. Furthermore, we investigated the mechanisms underlying the toxic effects of WAF on this benthic organism by studying expression patterns of cytochrome P450 (CYP) genes. Development of T. japonicus was delayed and molting was interrupted in response to WAF exposure. Hatching rate was also significantly reduced in response to WAF exposure. Activities of antioxidant enzymes such as glutathione S-transferase (GST), glutathione reductase (GR), and catalase (CAT) were increased by WAF exposure in a concentration-dependent manner. These results indicated that WAF exposure resulted in oxidative stress, which in turn was associated with dysfunctional development and reproduction. To evaluate the involvement of cytochrome P450 (CYP) genes, we cloned the entire repertoire of CYP genes in T. japonicus (n=52) and found that the CYP genes belonged to five different clans (i.e., Clans 2, 3, 4, mitochondrial, and 20). We then examined expression patterns of these 52 CYP genes in response to WAF exposure. Three TJ-CYP genes (CYP3024A2, CYP3024A3, and CYP3027C2) belonging to CYP clan 3 were significantly induced by WAF exposure in a time- and concentration-dependent manner. We identified aryl hydrocarbon responsive elements (AhRE), xenobiotic responsive elements (XREs), and metal response elements (MRE) in the promoter regions of these three CYP genes, suggesting that these genes are involved in detoxification of toxicants. Overall, our results indicate that WAF can trigger oxidative stress and thus induce dysfunctional development and reproduction in the copepod T. japonicus. Furthermore, we identified three TJ-CYP genes that represent potential biomarkers of oil pollution.
在这项研究中，我们通过生命周期实验研究了原油的水可溶部分（WAF）对潮间带桡足类动物 T. japonicus 的发育和繁殖的影响。此外，我们通过研究细胞色素 P450（CYP）基因的表达模式，研究了 WAF 对这种底栖生物的毒性作用的机制。WAF 暴露会导致 T. japonicus 的发育延迟和蜕皮中断，孵化率也显著降低。WAF 暴露会导致谷胱甘肽 S-转移酶（GST）、谷胱甘肽还原酶（GR）和过氧化氢酶（CAT）等抗氧化酶的活性呈浓度依赖性增加。这些结果表明，WAF 暴露导致了氧化应激，进而导致发育和繁殖功能障碍。为了评估细胞色素 P450（CYP）基因的参与，我们在 T. japonicus 中克隆了整个 CYP 基因库（n=52），并发现 CYP 基因属于五个不同的家族（即家族 2、3、4、线粒体和 20）。然后，我们研究了这些 52 个 CYP 基因在 WAF 暴露下的表达模式。属于 CYP 家族 3 的三个 TJ-CYP 基因（CYP3024A2、CYP3024A3 和 CYP3027C2）在时间和浓度依赖性方式下均被 WAF 诱导显著上调。我们在这三个 CYP 基因的启动子区域中鉴定出了芳基烃应答元件（AhRE）、异生物质应答元件（XRE）和金属应答元件（MRE），表明这些基因参与了有毒物质的解毒。总的来说，我们的研究结果表明，WAF 可以引发氧化应激，从而导致桡足类动物 T. japonicus 发育和繁殖功能障碍。此外，我们鉴定出了三个 TJ-CYP 基因，它们可能是石油污染的生物标志物。
