title: Interaction of ethidium bromide with the transport system for monovalent cations in yeast.
abstract: Ethidium was found to be taken up by yeast cells in a process that, at certain concentrations has the main following characteristics: a) a substrate is required; b) it presents cooperative kinetics, with n, according to the Hill equation approximately 3; c) ethidium can be concentrated more than 100-fold; d) the uptake is inhibited by Ca2+; e) the uptake of the dye is inhibited by monovalent cations with a selectivity pattern similar to that observed in their transport by yeast; f) ethidium inhibits the uptake of K+, and, at concentrations up to about 250 muM produces a competitive inhibition on the uptake of Rb+; and g) ethidium produces the same effects as K+ on respiration and the extrusion of H+. It is concluded that ethidium is taken up by yeast cells in a selective way by the same transport system normally employed for monovalent cation uptake.
mesh_terms: D001667:Binding, Competitive; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D002586:Cesium / Q000494:pharmacology; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D004996:Ethidium / Q000378:metabolism* / Q000494:pharmacology; D006859:Hydrogen / Q000378:metabolism; D008094:Lithium / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D012413:Rubidium / Q000378:metabolism / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D013793:Thallium / Q000494:pharmacology
chemical_list: D002586:Cesium; D011189:Potassium Chloride; D006859:Hydrogen; D008094:Lithium; D012964:Sodium; D013793:Thallium; D004996:Ethidium; D012413:Rubidium; D011188:Potassium; D002118:Calcium