Responses of antioxidant defenses in the clam Mactra veneriformis to 2,2 ',4, 4 '-tetrabromodiphenyl ether exposure

• Published in: Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology
• Main Authors: Dong, Shihang, Yang, Yanyan, Cheng, Bo, Ren, Chuanbo, Zhang, Huawei, Xu, Hua, Zhu, Na, Wang, Wansheng, Dang, Yongjian, Li, Mingzhu, Chen, Jun, Wang, Kai, Zhang, Libin, Fang, Yan
• Format: Report
• Language: English
• Published: ELSEVIER SCIENCE INC 2019
• Subjects: Catalase; Glutathione peroxidase; Superoxide dismutase; 2,2 ',4,4 '-Tetrabromodiphenyl ether; Malondialdehyde; Mactra veneriformis; Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology; POLYBROMINATED DIPHENYL ETHERS; MESSENGER-RNA EXPRESSION; MUSSEL WATCH PROGRAM; SUPEROXIDE-DISMUTASE; OXIDATIVE STRESS; MYTILUS-GALLOPROVINCIALIS; MOLECULAR-CLONING; DIGESTIVE GLAND; ENZYME-ACTIVITY; PACIFIC OYSTER; Pacific; Pacific oyster
• Online Access: http://ir.qdio.ac.cn/handle/337002/161145; https://doi.org/10.1016/j.cbpc.2018.12.003

Antioxidant enzymes play essential roles against oxidative stress caused by 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), which is ubiquitous in marine environment and organisms. However, research on antioxidant responses to BDE-47 in marine bivalves is scarce. In this study, we identified the full-length cDNA of catalase (CAT), and glutathione peroxidase (GPx) in the clam Mactra veneriformis. Subsequently, the responses of CAT, GPx, and copper, zinc-superoxide dismutase (Cu, Zn-SOD) were investigated in the clams exposed to 0.1, 1, and 10 mu g/L BDE-47 for 7 days, and then depurated in natural seawater for 3 days. MvCAT and MvGPx contained conserved sequences. The deduced amino acid sequences shared high similarity with CATs and GPxs in other mollusks. M. veneriformis accumulated BDE-47 in a dose-dependent manner and eliminated BDE-47 poorly. BDE-47 induced a time- and dose-dependent increase of malondialdehyde content. Both the dose and the duration had significant effect on mRNA expressions and activities of the three antioxidants. Cu, Zn-SOD responded to BDE-47 earlier than CAT and GPx. The antioxidant responses could recover after depuration. These results suggested that M. veneriformis could accumulate BDE-47 efficiently. Antioxidant enzymes were triggered to counter the oxidative stress generated by BDE-47. Cu, Zn-SOD acted as the first defense against oxidative stress, while CAT and GPx intervened later. This study is therefore helpful in understanding the antioxidant responses to PBDEs in marine bivalves.