title: Effect of cadmium and lead on the membrane potential and photoelectric reaction of Nitellopsis obtusa cells.
abstract: The effects of Cd and Pb on membrane potential (E(m)) and photoelectric reaction of Nitellopsis obtusa cells were investigated. It was found that Cd and Pb at 1.0 mM caused a depolarization of the E(m), whereas both metals at lower concentrations changed the E(m) in a different way. Pb at 0.1 mM and 0.01 mM hyperpolarized the E(m), whereas Cd at the same concentrations depolarized and did not change the E(m), respectively. In the presence of 0.01 mM Pb, the light-induced hyperpolarization of the E(m) was by 18% higher as compared to the control, whereas at 1.0 mM Pb it was by 40% lower. Pb at 0.1 mM and Cd at 0.01 mM or 5 × 0.01 mM did not change the light-induced membrane hyperpolarization. However, in the presence of Cd at 0.1 mM and 1.0 mM this hyperpolarization was 2-fold lower or was completely abolished, respectively. These results suggest that at high Cd and Pb concentrations both depolarization of the E(m) and decrease of light-induced membrane hyperpolarization in Nitellopsis obtusa cells are probably due to inhibition of the plasma membrane H(+)-ATPase activity, whereas both metals at lower concentrations differ in mechanism of membrane potential changes.
authors: Department of Plant Physiology, Faculty of Biology and Environmental Protection, University of Silesia, ul. Jagiellońska 28, 40 032 Katowice, Poland. renata.kurtyka@us.edu.pl
authors: Renata
authors: R
authors: Kurtyka
authors: Zbigniew
authors: Z
authors: Burdach
authors: Waldemar
authors: W
authors: Karcz
mesh_terms: D002104:Cadmium / Q000633:toxicity*; D002462:Cell Membrane / Q000187:drug effects; D044522:Characeae / Q000187:drug effects / Q000378:metabolism; D000460:Chlorophyta / Q000187:drug effects* / Q000378:metabolism; D007854:Lead / Q000633:toxicity*; D008564:Membrane Potentials / Q000187:drug effects*; D008670:Metals / Q000633:toxicity; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000187:drug effects
chemical_list: D008670:Metals; D002104:Cadmium; D007854:Lead; D006180:Proton-Translocating ATPases