Crude oil exposure results in oxidative stress-mediated dysfunctional development and reproduction in the copepod Tigriopus japonicus and modulates expression of cytochrome P450 (CYP) genes

• Published in: Aquatic toxicology 2014-07, Vol.152, p.308-317
• Main Authors: Han, Jeonghoon, Won, Eun-Ji, Hwang, Dae-Sik, Shin, Kyung-Hoon, Lee, Yong Sung, Leung, Kenneth Mei-Yee, Lee, Su-Jae, Lee, Jae-Seong
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Copepod; Copepoda; Copepoda - classification; Copepoda - drug effects; Copepoda - enzymology; Copepoda - genetics; CYP; Cytochrome P-450 Enzyme System - genetics; Cytochrome P450; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - drug effects; Growth and Development - drug effects; Oxidative stress; Oxidative Stress - drug effects; Oxidoreductases - genetics; Petroleum - toxicity; Phylogeny; Promoter Regions, Genetic - genetics; Reproduction - drug effects; Tigriopus japonicus; Water accommodated fraction; Water Pollutants, Chemical - toxicity
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2014.04.027

•52 CYP genes were found from T. japonicus.•Development, molting, and hatching rate were affected in response of WAF exposure in T. japonicus.•WAF exposure induced oxidative stress.•CYP3024A2, CYP3024A3, and CYP3027C2 were significantly induced by WAF.•Promoter regions of CYP genes are useful to understand the mode of action for detoxification. 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.