Open AccessChanges in 45Ca and 109Cd Uptake, Membrane Potential and Cell pH in Saccharomyces cerevisiae Provoked by Cd2+
Author(s) -
B. G. F. Kessels,
A.P.R. Theuvenet,
P.H.J. Peters,
J. Dobbelmann,
G.W.F.H. Borst-Pauwels
Publication year - 1987
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-133-4-843
Subject(s) - divalent , hyperpolarization (physics) , saccharomyces cerevisiae , chemistry , biophysics , membrane , membrane potential , cell permeability , biochemistry , cell membrane , efflux , cell , biology , yeast , stereochemistry , nuclear magnetic resonance spectroscopy , organic chemistry
The effect of Cd2+ poisoning of Saccharomyces cerevisiae on 45Ca, 109Cd and [14C]tetraphenylphosphonium (TPP) uptake and cell pH was examined. At Cd2+ concentrations that produced substantial K+ efflux the rates of uptake of 45Ca, 109Cd and [14C]TPP increased progressively during incubation of the cells with Cd2+, and the cell pH was lowered concomitantly. The initial rates of uptake of the divalent cations and of TPP were increased in cells pre-loaded with Cd2+, which shows that stimulation of the ion fluxes was exerted by the Cd2+ that accumulated in the cells. The distribution ratio of TPP between cells and medium, however, was decreased by Cd2+. Although hyperpolarization of the cell membrane by Cd2+ cannot be excluded, it is argued that Cd2+ primarily stimulated divalent cation uptake by increasing the cation permeability of the cell membrane allowing the cations to enter the cells more easily.