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.
CEA, iBiTecS, CNRS URA 2096, Service de Bioénergétique Biologie Structurale et Mécanisme, 91191 Gif-sur-Yvette Cedex, France.
Eiri
E
Heyno
Institut für Biologie II, Universität Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
Cornelia
C
Klose
CEA, iBiTecS, CNRS URA 2096, Service de Bioénergétique Biologie Structurale et Mécanisme, 91191 Gif-sur-Yvette Cedex, France.
Anja
A
Krieger-Liszkay
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