Effect of prooxidants on yeast mitochondria

Abstract

Tightly coupled mitochondria from Yarrowia lipolytica and Dipodascus (Endomyces) magnusii yeasts were used in this study. The two yeasts are aerobes containing the fully competent respiratory chain with three energy conservation sites. Interaction of the yeast mitochondria with prooxidants (diamide, menadione, oxaloacetate, phenylarsine oxide, hydrogen peroxide, t-butyl peroxide, and ascorbate plus Fe(2+)) was studied. The prooxidants, depending on their chemical nature, either caused uncoupling (e.g., activated state 4 respiration) or inhibited oxidation of respiratory substrates. All of the agents dissipated the membrane potential without megachannel formation (no large-scale swelling of mitochondria was observed). Except for combined application of ascorbate and Fe(2+), the prooxidant-induced decrease in the membrane potential was specifically prevented by ATP, even in the cases when classic antioxidants, e.g., N-acetylcysteine, were ineffective. No permeabilization of yeast mitochondria was observed under concerted action of prooxidants and Ca(2+), suggesting that an mPTP-like pore, if it ever occurs in yeast mitochondria, is not coupled with Ca(2+) uptake.

The contribution of Saccharomyces cerevisiae replicative age to the variations in the levels of Trx2p, Pdr5p, Can1p and Idh isoforms

“…Indeed, on the one hand, dysfunctional mitochondria promote ROS accumulation in the cells 32 . On the other hand, ROS can induce depolarization of mitochondria 48 , 49 in this way inhibiting mitochondrial fusion and promoting fragmentation of mitochondrial network 50 , 51 . We did not find any indications of early age-associated ROS increase — there was no correlation between Trx2-GFP levels and replicative age in our experiments (Fig.…”

Role of charge screening and delocalization for lipophilic cation permeability of model and mitochondrial membranes

“…Respiring mitochondria maintained their ΔΨ for a long time without any swelling (Kovaleva et al, 2009). Tightly-coupled yeast mitochondria have some advantages over animal mitochondria as they lack a Ca 2+ /P i -dependent pore (Kovaleva et al, 2009(Kovaleva et al, , 2010Trendeleva et al, 2011aTrendeleva et al, , 2011b, a fact facilitating interpretation of the data obtained.…”

Inhibition of free radical scavenging enzymes affects mitochondrial membrane permeability transition during growth and aging of yeast cells

“…Until recently it has been widely accepted, that in yeast cells no classical mPTP can be induced [Trendeleva et al 2011a;Trendeleva et al 2011b]. However, we have identified the direct relationship between activity of ROS-scavenging enzyme systems and loss of mitochondrial membrane integrity with some symptoms of mPTP (Deryabina et al 2013).…”