Molecular cloning, characterization of CAT, and eco-toxicological effects of dietary zinc oxide on antioxidant enzymes in Eisenia fetida

作者：Xiong, Wenguang; Sun, Yongxue^*; Zou, Mengjia; Muhammad, Rizwan-Ul-Haq

来源：Environmental Science and Pollution Research, 2013, 20(3): 1746-1755.

DOI：10.1007/s11356-012-1408-9

• Dietary ZnO
• cDNA cloning
• Antioxidant
• Eisenia fetida
• Eco-toxicology
• Biomarker

The full-length cDNA of catalase (EfCAT) from Eisenia fetida was cloned (GenBank accession no. JN617999). Sequence characterization revealed that EfCAT protein sequence contained proximal heme-ligand signature sequence ((RLFSYSDTH359)-R-351), two glycosylation sites (N-145 and N-436), the proximal active site signature ((61)FDRERIPERVVHAKGAGA(78)), and 12 amino acids (N-145, H-191, F-195, S-198, R-200, N-210, Y-212, K-234, I-299, W-300, Q(302), and Y-355), which were identified as putative residues involved in NADPH binding. These conserved motifs and catalase signature sequences were essential for the structure and function of EfCAT. The present study also investigated the effect of the veterinary food additive zinc oxide on antioxidant processes in E. fetida, at different concentrations and exposure durations. A significant increase (by 106.0 % compared to controls) in CAT activity at 500 mg/kg was registered at day 15. The superoxide dismutase (SOD) activity at 500 mg/kg increased to the maximum value (by 44.0 %) measured at day 15. There was a significant increase in glutathione peroxidase (GPx) activity for all concentrations after 5 days. The results showed that dietary Zn (500 mg/kg) causes oxidative damage to earthworms. At early stages of earthworms exposed to ZnO, GPx is the main enzyme to impair the oxidative status; while at later stages the enzymes CAT and SOD were the main indicators of oxidative stress. The antioxidant enzymatic variations may be an adaptive response of earthworms to survive in contaminated soils.

• 出版日期2013-3
• 单位华南农业大学