Iron toxicity in yeast.
It has been found that yeast cells are sensitive to iron overload only when grown on glucose as a carbon source. Effective concentration of ferrous iron is much higher than that found in natural environments. Effects of ferrous iron are strictly oxygen dependent, what suggest that the formation of hydroxyl radicals in the Fenton reaction is a cause of the toxicity. Respiratory deficiency and pretreatment of cells with antimycin A prevent toxic effects in the late exponential phase of growth, whereas uncouplers and 2mM magnesium salts completely protect even the most vulnerable exponential cells. Generally, toxic effects correlate with the ability of cells to take up this metal. The results presented suggest that during ferrous iron overload iron is transported through the unspecific divalent cation uptake system which is known in fungi. The data suggest that recently described high and low affinity systems of iron uptake in yeast are the only source of iron in natural environments.
Wiśnicka
R
R
Zamość College of Agriculture, Agricultural University of Lublin, Poland.
Krzepiłko
A
A
Wawryn
J
J
Biliński
T
T
D000968:Antimycin A / Q000494:pharmacology; D001692:Biological Transport; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D003470:Culture Media; D004140:Dinitrophenols / Q000494:pharmacology; D005296:Ferrous Compounds / Q000378:metabolism / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D010101:Oxygen Consumption; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D014475:Uncoupling Agents / Q000494:pharmacology
D003470:Culture Media; D004140:Dinitrophenols; D005296:Ferrous Compounds; D014475:Uncoupling Agents; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000968:Antimycin A; D008274:Magnesium; D005947:Glucose