FIGURE 3.

Impact of intracellular superoxide generator menadione on growth rate and superoxide dismutase (SOD) activity. (a) The wildtype strain Vd991, VdSOD1 deletion strains, and the complemented (EC) strains were cultured on potato dextrose agar (PDA) supplemented with menadione at specified concentrations for 9 days. (b–d) Colony diameters on PDA plates containing different concentration of menadione following 5 days (b), 7 days (c), and 9 days (d) of incubation. Means and standard deviations of the mean from three biological replicates are shown. Asterisks (**) denote significant differences (p < 0.01) according to Student's t test. (e) The total SOD activity of mycelial protein extract of the wildtype strain, ΔSOD1 strains, and complemented strains were detected using the nitroblue tetrazolium (NBT) reduction method. All strains were stressed with 10 μM menadione for 24 hr. Means and error bars (represent standard deviation) are from three independent experiments. Asterisks (**) mean significant differences (p < 0.01) according to Student's t test