New yeast models for studying mitochondrial morphology as affected by oxidative stress and other factors.

The overwhelming majority of investigations on mitochondrial morphology were performed using S. cerevisiae. In this study we showed the benefits of applying new model organisms including petite-negative D. magnusii and Y. lipolytica yeasts for visualization of mitochondrial fragmentation. Normally giant D. magnusii cells and filament-like Y. lipolytica cells contain the highly structured mitochondrial reticulum. Oxidative stress mediated by tert-butyl hydroperoxide triggered mitochondrial fragmentation in yeasts. In D. magnusii mitochondrial fragmentation was also induced by impairing the oxidative phosphorylation system. Higher prooxidant concentrations caused cell death. Cationic lipophilic antioxidant SkQ1 acted downstream of the excessive ROS production and prevented partially or almost totally oxidative stress and related mitochondrial fragmentation and cell death. We believe that utility of D. magnusii and Y. lipolytica yeasts as a "living test tube" would be useful for providing new information concerning the interplay between mitochondrial dynamics and mitochondrial dysfunction, cell cycle, aging, mitophagy and cell death.