Figure 5. Oxidative stress initiates mitochondrial tubularization.

(a–j) Yeasts from four outbreak and four non-outbreak strains, presenting with differing abilities to proliferate intracellularly, were assessed for mitochondrial tubularization on exposure to several stresses (linear regression). Treatment with 0.7 mM H₂O₂ (b) was the strongest initiator for tubularization. Data were obtained for eight C. gattii strains from at least nine individual experiments determining IPR and at least three individual experiments examining mitochondrial morphology in 502 to 4,859 yeasts (Supplementary Table 4). Statistical significance of correlations was assessed using Pearson correlation (a–i), whereas categorical data (tubular versus non-tubular mitochondria) between outbreak and non-outbreak strains from a set of four strains per group and three independent experiments observing between 3,402 and 23,881 yeasts (Supplementary Table 5) were analysed by Fisher’s exact test or χ²-test (j).