Origin of cadmium-induced reactive oxygen species production: mitochondrial electron transfer versus plasma membrane NADPH oxidase.
* Cadmium (Cd(2+)) is an environmental pollutant that causes increased reactive oxygen species (ROS) production. To determine the site of ROS production, the effect of Cd(2+) on ROS production was studied in isolated soybean (Glycine max) plasma membranes, potato (Solanum tuberosum) tuber mitochondria and roots of intact seedlings of soybean or cucumber (Cucumis sativus). * The effects of Cd(2+) on the kinetics of superoxide (O2*-), hydrogen peroxide (H(2)O(2)) and hydroxyl radical ((*OH) generation were followed using absorption, fluorescence and spin-trapping electron paramagnetic resonance spectroscopy. * In isolated plasma membranes, Cd(2+) inhibited O2*- production. This inhibition was reversed by calcium (Ca(2+)) and magnesium (Mg(2+)). In isolated mitochondria, Cd(2+) increased and H(2)O(2) production. In intact roots, Cd(2+) stimulated H(2)O(2) production whereas it inhibited O2*- and (*)OH production in a Ca(2+)-reversible manner. * Cd(2+) can be used to distinguish between ROS originating from mitochondria and from the plasma membrane. This is achieved by measuring different ROS individually. The immediate (<or= 1 h) consequence of exposure to Cd(2+) in vivo is stimulation of ROS production in the mitochondrial electron transfer chain and inhibition of NADPH oxidase activity in the plasma membrane.
Heyno
Eiri
E
CEA, iBiTecS, CNRS URA 2096, Service de Bioénergétique Biologie Structurale et Mécanisme, 91191 Gif-sur-Yvette Cedex, France.
Klose
Cornelia
C
Institut für Biologie II, Universität Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
Krieger-Liszkay
Anja
A
CEA, iBiTecS, CNRS URA 2096, Service de Bioénergétique Biologie Structurale et Mécanisme, 91191 Gif-sur-Yvette Cedex, France.
D019256:Cadmium Chloride / Q000633:toxicity*; D002122:Calcium Chloride / Q000494:pharmacology; D002458:Cell Fractionation; D002462:Cell Membrane / Q000187:drug effects* / Q000201:enzymology; D018553:Cucumis sativus / Q000187:drug effects / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D018546:Hypocotyl / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors*; D018384:Oxidative Stress; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D010944:Plants / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000737:chemistry / Q000378:metabolism*; D011198:Solanum tuberosum / Q000187:drug effects / Q000378:metabolism; D013025:Glycine max / Q000187:drug effects / Q000378:metabolism
D004785:Environmental Pollutants; D017382:Reactive Oxygen Species; D015636:Magnesium Chloride; D019255:NADPH Oxidases; D019256:Cadmium Chloride; D002122:Calcium Chloride