Protection of Saccharomyces cerevisiae against Cd2+ Toxicity by Ca2+

Abstract

Ca)+ protected yeast cells very effectively against the toxic effects of Cd2+; Mg2+ had only a slight protecting effect as far as protection against Cd'+-induced release of K + was concerned. Protection of the yeast cells against Cd'+ toxicity was due to a reduction in Cd'+ uptake in the presence of Ca2+. A single relationship existed between the relative rate of K+ release induced by Cd2+ and the celldar Cd'+ concentration. Within the first few minutes of incubating cells with Cd'+, the molar ratio of K+ released and Cd'+ accumulated was 22 and was independent of the amount of CdCl, added. This ratio decreased during incubation of the cells with Cd'+, depending on the external Cd2+ concentration.

Changes in 45Ca and 109Cd Uptake, Membrane Potential and Cell pH in Saccharomyces cerevisiae Provoked by Cd2+

“…The specific activities of Io9Cd and 4sCa were 0.9 Ci mmol-' (33.3 GBq mmol-') and 9.2 mCi mmol-I (340.4 MBq mmol-I), respectively. Nitrogen was bubbled through the suspension at 25 "C and at appropriate times 2 ml samples were filtered and washed (Kessels et al, 1985). Radioactivity on the filters was determined by liquid scintillation counting.…”

“…Cd2+ is very toxic to all kinds of living cells including yeasts (Norris & Kelly, 1977;Gadd & Mowl, 1983;Kessels et al, 1985;Heldwein et al, 1977;Macara, 1978;Bitton et ul., 1984). Not only is growth inhibited but Cd2+ also provokes K+ loss from metabolizing yeast cells (Norris & Kelly, 1977;Gadd & Mowl, 1983;Kessels et al, 1985).…”

“…Not only is growth inhibited but Cd2+ also provokes K+ loss from metabolizing yeast cells (Norris & Kelly, 1977;Gadd & Mowl, 1983;Kessels et al, 1985). Cd2+ must first enter the cells before giving rise to a detectable effect (Kessels et al, 1985).…”

OmZnT1 and OmFET, two metal transporters from the metal-tolerant strain Zn of the ericoid mycorrhizal fungus Oidiodendron maius, confer zinc tolerance in yeast

“…The effect of intracellular and extracellular magnesium concentrations on heavy metal toxicity has been described in several studies, although the mechanisms have not been elucidated. A general protective effect of magnesium against heavy-metal cations such as manganese, copper, nickel, cadmium and cobalt in yeast ( Blackwell et al, 1998, Karamushka and Gadd, 1994, Joho et al, 1991, Kessels et al, 1985and Norris and Kelly, 1979, and zinc and cadmium in plants ( Pedler et al, 2004 andKupper andKochian, 2010) has been reported. In particular, the uptake of divalent cations in yeast was reduced by the addition of extracellular magnesium ( Pisat et al, 2009, Blackwell et al, 1998and Bianchi et al, 1981.…”

Effects of nickel on the mineral composition of Fleischmann’s yeast (Saccharomyces cerevisiae)

“…Heavy metals may damage the yeast cell membrane by fluidizing it, which causes potassium channels to open and its intracellular level to decrease 4,9,16 .…”