FIGURE 4. Assessment of the intracellular accumulation of ROS in S. cerevisiae BY4741 cells cultivated in MMB medium (at pH 3.5) (white bars) or in this same medium supplemented with 0.5 mM SO₂ (grey bars). Quantification of intracellular ROS accumulation was made based on fluorescence emitted by cells stained with the ROS specific dyes DHE (A) and DHR123 (B) and analysed by flow cytometry. Significance was determined by two-way ANOVA (*p≤0.05, ***p≤0.001) between cells at time 0 and 200 minutes and between control cells and cells supplemented with SO₂. Data represents mean ± SEM (the standard error of the mean) of at least three biological independent replicas.