Antioxidant response of Daphnia magna exposed to no. 20 diesel oil

Abstract

This is the first report of the antioxidant response of Daphnia magna following a short-term response to the water soluble fractions of no. 20 diesel oil. Daphnia magna was exposed for 24h to nominal concentrations of 0, 0.005, 0.01, 0.05, 0.1, 0.5 or 1.0 mg/L diesel oil. Following this exposure, the activities of catalase (CAT) and glutathione S-transferase (GST) were induced significantly on the whole compared to control group; the activity of selenium-dependent glutathione peroxidase (Se-GPx) were inhibited significantly on the whole; the activity of superoxide dismutase (SOD) only responded to diesel oil exposure at the two highest exposure concentrations; the activity of glutathione reductase (GR) and the content of reduced glutathione (GSH) were greatly activated in Group 4; and the content of oxidized glutathione (GSSG) were induced at two different concentrations. Total glutathione (tGSH) and GSH/GSSG ratio were also calculated to analyze the occurrence of oxidative stress. In conclusion, CAT, GST and tGSH could be potential early warning signals for short-term effects of diesel oil in aquatic ecosystems, and further studies are needed.