Role of cell wall in Saccharomyces cerevisiae mutants resistant to Hg2+.
Hg2+-resistant mutants were isolated from Saccharomyces cerevisiae. Although they were very much like the parental strains in terms of colony-forming ability, they grew faster than the parental strains in the presence of sublethal doses of Hg2+. The Hg2+-resistant mutations were dominant. They were centromere linked and were divided into two groups by means of recombination; one of the mutations, designated HGR1-1, was mapped on chromosome IV because of its linkage to the TRP1 locus. The Hg2+-resistant mutants took up Hg2+ as much as, or slightly more than, the parental strains did. The mutants and parental strains retained only about 5 and 15%, respectively, of the cell-associated Hg2+ after removal of the cell wall; therefore, the mutants had less spheroplast-associated Hg2+ than did the parental strains. These results indicate that the cell wall plays an important role in protection against Hg2+ by acting as an adsorption filter and that the mutations described confer Hg2+ resistance by increasing the Hg2+-binding capacity of the cell wall.
Ono
B
B
Laboratory of Environmental Hygiene Chemistry, Faculty of Pharmaceutical Sciences, Okayama University, Japan.
Ohue
H
H
Ishihara
F
F
D001692:Biological Transport; D002473:Cell Wall / Q000502:physiology*; D004352:Drug Resistance, Microbial / Q000235:genetics; D007700:Kinetics; D008628:Mercury / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D013104:Spheroplasts / Q000502:physiology
D008628:Mercury