Total catalase activity (left panels) and cell viability (right panels) of wild-type yeast cells in the YPH250 (A and B, respectively) and BY4741 (C and D, respectively) genetic background following H2O2 challenge. Exponentially growing cells (12h OD600=0.5) in YPD medium were exposed to Kpi (Control, gray bars) or challenge with 0.2-2mM H2O2 (green bars) for 1.5h at 30⁰C and 225 rpm.