FIGURE 2: The deletion of TOR1 and SCH9 abolishes the shortened CLS, oxi-dative stress sensitivity and mitochondrial dysfunctions displayed by isc1Δ cells.

(A) S. cerevisiae BY4741, isc1Δ, tor1Δ and isc1Δtor1Δ, sch9Δ and isc1Δsch9Δ cells were grown in SC-medium and kept in the medium at 26^oC. The viability was determined by standard dilution plate counts and expressed as the percentage of the colony-forming units at time T in relation to T₀. Values are mean ± SD of at least three inde-pendent experiments.

(B, C) Yeast cells were grown in SC-medium to the exponential phase (B) or stationary phase (48 hours after exponential phase) (C) and exposed to 1.5 mM H₂O₂ for 60 min (B) or 300 mM H₂O₂ for 30 min (C). Cell viability was determined by standard dilution plate counts and expressed as the percentage of the colony-forming units (treated cells versus untreated cells). Values are mean ± SD of at least three independent experiments. ****p<0.0001. ***p<0.001.

(D) S. cerevisiae BY4741, isc1Δ, tor1Δ and isc1Δtor1Δ, sch9Δ and isc1Δsch9Δ cells were grown in SC-medium to the exponential phase and then diluted to OD₆₀₀=0.1. Fivefold dilution series were spotted on YPD (glucose) or YPG (glycerol) medium and cells were grown at 26^oC for 4 days.

(E) Oxygen consumption rate was measured in cells grown to PDS phase, as described in Materials and Methods. Values are mean ± SD of at least three independent experiments. ****p<0.0001; *p<0.05.

(F) Cytochrome c oxidase (COX) activity was determined in cells grown to the PDS phase. Cells were lysed and enzymatic activity was measured as described in Materials and Methods. Values are mean ± SD of at least three independent experiments. ****p<0.0001; ***p<0.001