The Effect of Bisphenol A on Growth, Morphology, Lipid Peroxidation, Antioxidant Enzyme Activity, and PS II in Cylindrospermopsis raciborskii and Scenedesmus quadricauda

To investigate the effect of bisphenol A (BPA) on Cylindrospermopsis raciborskii (Cyanobacteria) and Scenedesmus quadricauda (Chlorophyta), we grew the two species at BPA concentrations of 0, 0.1, 1, 2, 5, 10, and 20 mg/L and examined their growth, lipid peroxidation, antioxidant enzyme activity, and chlorophyll a fluorescence. The 96-h EC50 values (effective concentration causing 50% growth inhibition) for BPA in C. raciborskii and S. quadricauda were 9.663 +/- 0.047, and 13.233 +/- 0.069 mg/L, respectively. A significant reduction in chlorophyll a concentration was found in C. raciborskii and S. quadricauda when BPA concentrations were greater than 1 and 2 mg/L, respectively. Furthermore, F (v)/F (m), Delta F/F (m)', and qP decreased significantly at 10 mg/L BPA in C. raciborskii but started to decrease at 10 mg/L in S. quadricauda. The changes in chlorophyll fluorescence parameters (alpha, rETR(max)) that were obtained from the rapid light response curves of both algae species showed similar responses to F (v)/F (m), Delta F/F (m)', and qP under BPA-induced stress. Values for all of the chlorophyll fluorescence parameters in S. quadricauda were higher than in C. raciborskii; however, the nonphotochemical quenching measured in C. raciborskii was considerably higher than it was in S. quadricauda. In addition, lipid peroxidation (determined as MDA content) and antioxidant enzyme activities (SOD and CAT) increased in both species as the BPA concentration increased. These results suggest that C. raciborskii is more sensitive to the effects of BPA than S. quadricauda and that photosystem II might be a target for the activity of BPA in vivo.