All experiments were performed a minimum of three times. LC 50 values were determined by PROBIT analysis [43] . The lethal concentration assays are represented graphically using nonlinear regression performed with the software GraphPad Prism. Statistical analysis between two values was compared with a paired t-test. Statistical analysis among three or more values was compared with matched one way ANOVA using the Tukey post test. Lifespan data was analyzed with Kaplan-Meier survival curves. Statistical significance was set at p,0.05.