Cloning of AwCAT from Anodonta woodiana and the Effect of PBDE on Its Transcription

Catalase (CAT) is a major reactive oxygen species (ROS) scavenger enzyme that plays a significant role in the antioxidant defense mechanism of organisms by reducing toxic hydrogen peroxide molecules into a nontoxic form of oxygen and water with a high turnover rate. Polybrominated diphenyl ethers (PBDEs) are currently important components in flame retardants. Excess PBDEs deposited in organism could catalyze the production of ROS. In current study, one complete CAT sequence was isolated from Anodonta woodiana and named AwCAT . The full-length AwCAT cDNA of A. woodiana consists of 1 784 nucleotides. The open reading frame contains 1 536 bp nucleotides and encodes 512 amino acids. Compared with that of control group, AwCAT mRNA level of hepatopancreas increased more than 66.66% (P<0.05), 1.35 times (P<0.05), 1.54 times (P<0.05), 1.97 times (P<0.01) and 2.39 times (P<0.01) in the 6.25, 12.5, 25, 50 and 100 μg·L-1 of PBDE-47 treated groups, respectively; AwCAT mRNA level of hepatopancreas increased more than 7.84%, 35.38%, 61.53% (P<0.05), 1.03 times (P<0.05) and 1.09 times (P<0.05) in the 10, 20, 40, 80 and 160 μg·L-1 of PBDE-209 treated group, respectively. Compared with that of control group, AwCAT mRNA level of gill significantly increased in the PBDE-47 treated groups. Compared with that of control group, AwCAT mRNA level of gill increased more than 85.71% (P<0.05) in the PBDE-209 treated goups. These results indicate that up-regulations of AwCAT expression of hepatopancreas and gill in the freshwater bivalve A. woodiana are contributed to eliminate stress derived from PBDE-47 and PBDE-209 challenge.