To investigate the toxic effects of microcystin (MC) on microalgae cells and elucidate the mechanism of cell death and responses of antioxidant systems in microalgae to oxidative stress induced by MC from the perspective of reactive oxygen species (ROS), the changes of cell growth, ROS production and antioxidant systems in the cells were determined using 50 mu g . L-1 and 500 mu g . L-1 MC-LR to treat Aphanizomenon sp. DC01 cells. Results showed that 50 mu g . L-1 MC-LR had no significant effects on the growth of Aphanizomenon sp. DCO1 while 500 mu g . L-1 MC-LR induced cell death of Aphanizomenon sp. DC01. The ROS content in 50 mu g . L-1 MC-LR treated cells was significantly higher than that in the control group after 2 days toxin exposure, but Aphanizomenon cells could rehabilitate the oxidative injury through changes of glutathione (GSH) content and superoxide dismutase(SOD), glutathione peroxidas (GPX) activities. ROS content recovered to the control level after 3 days. 500 mu g-L-1 MC-LR treat significantly decreased GSH content and SOD, GPX activities, and induced the excessive production of ROS in Aphanizomenon cells. ROS production burst after 4d toxin exposure, causing lipid peroxidation of Aphanizomenon cells, which led to cell death at last.
Hu Zhi-quan (zhiquanhu@yahoo.com.cn) ; Xiao Bo; Liu Yong-ding (liuyd@ihb.ac.cn).Effects of microcystin-LR on the growth and antioxidant systems in Aphanizomenon sp DC01 cells,Asian Journal of Ecotoxicology,2008,3(4):377-382
