Figure 7.

Truncated Sod2 is protective against superoxide stress during Cu limitation. A, in vitro total SOD activity assays of whole cell extracts from WT C. neoformans cells supplemented with 1 mM BCS or 0.1 mM CuSO₄. Assays were repeated in the presence of KCN to detect SOD activity because of the contribution of Sod2. N = 3, 2-tailed t test. B, In vivo cellular superoxide sensitivities as tested by disc diffusion assays in the indicated strains and in the presence of 1 mM BCS or 0.1 mM CuSO₄. Cells were challenged by spotting increasing concentrations of the superoxide generator menadione on filter discs and allowing cells to incubate at 30 °C for 3 days. Menadione concentrations spotted onto discs are listed on key to the right. ∗p < 0.05, ∗∗∗p < 0.005, n.s., not significant. BCS, bathocuproinedisulfonic acid; SOD, superoxide dismutase.