title: Reactive oxygen species inhibit the succinate oxidation-supported generation of membrane potential in wheat mitochondria.
abstract: In order to gain a first insight into the effects of reactive oxygen species (ROS) on plant mitochondria, we studied the effect of the ROS producing system consisting of xanthine plus xanthine oxidase on the rate of membrane potential (DeltaPsi) generation due to either succinate or NADH addition to durum wheat mitochondria as monitored by safranin fluorescence. We show that the early ROS production inhibits the succinate-dependent, but not the NADH-dependent, DeltaPsi generation and oxygen uptake. This inhibition appears to depend on the impairment of mitochondrial permeability to succinate. It does not involve mitochondrial thiol groups sensitive to either mersalyl or N-ethylmaleimide and might involve both protein residues and/or membrane lipids, as suggested by the mixed nature. We propose that, during oxidative stress, early generation of ROS can affect plant mitochondria by impairing metabolite transport, thus preventing further substrate oxidation, DeltaPsi generation and consequent large-scale ROS production.
authors.affiliation: Dipartimento di Scienze Animali, Vegetali e dell'Ambiente, Facoltà di Agraria, Università del Molise, Via De Sanctis, 86100, Campobasso, Italy.
authors.forename: Donato
authors.initials: D
authors.lastname: Pastore
authors.forename: Maura Nicoletta
authors.initials: MN
authors.lastname: Laus
authors.forename: Natale
authors.initials: N
authors.lastname: Di Fonzo
authors.forename: Salvatore
authors.initials: S
authors.lastname: Passarella
mesh_terms: D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008634:Mersalyl / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D008954:Models, Biological; D009243:NAD / Q000378:metabolism; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013386:Succinates / Q000494:pharmacology; D019802:Succinic Acid / Q000378:metabolism*; D014908:Triticum / Q000187:drug effects / Q000378:metabolism*; D019820:Xanthine / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000494:pharmacology
chemical_list: D017382:Reactive Oxygen Species; D013386:Succinates; D009243:NAD; D019820:Xanthine; D008634:Mersalyl; C017625:2-phenylsuccinate; D019802:Succinic Acid; D014969:Xanthine Oxidase