Fig. 2.

Superoxide and NO levels intetO₇YFH1andtetO₇YFH1Δyhb1strains. Yeast cells were grown in YPG and, where indicated, doxycycline was added to the culture media for 6 h in order to repress Yfh1 expression. A, Superoxide production was measured using DHE; B, NO levels were measured using DAF-FM DA and flow cytometry; C, the presence of nitrotyrosines was evaluated in crude extracts by western blot using antibodies which recognize this prostraductional modification. Histograms represent relative nitrotyrosine content in each condition, which was calculated from the chemiluminescent signal of each lane of the western blot analyzed with Quantity One software (Bio-Rad). Nitrotyrosine levels in tetO₇YFH1 control cultures were used as a reference value. From A to C, data are represented as means±SD from 3 independent experiments. * and ** indicate significant (p < 0.05) or highly significant (p < 0.01) differences, respectively, when compared to control condition.