title: Enhancements in ethanol tolerance of a self-flocculating yeast by calcium ion through decrease in plasmalemma permeability.
abstract: Ca2+ at 1.64 mmol/L markedly increased ethanol tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae. After 9 h of exposure to 20% (V/V) ethanol at 30 degrees C , no viability remained for the control whereas 50.0% remained for the cells both grown and incubated with ethanol in Ca2+ -added medium. Furthermore, when subjected to 15% (V/V) ethanol at 30 degrees C, the equilibrium nucleotide concentration and plasma membrane permeability coefficient (P' ) of the cells both grown and incubated with ethanol in Ca2+ -added medium accounted for only 50.0% and 29.3% those of the control respectively, indicating that adding Ca2+ can markedly reduce plasma membrane permeability of yeast cells under ethanol stress as compared with the control. Meanwhile, high viability levels acquired by the addition of Ca2+ exactly corresponded to the striking decreases in extracellular nucleotide concentration and P' achieved with identical approach. Therefore, the enhancing effect of Ca2+ on ethanol tolerance of this strain is closely related to its ability to decrease plasma membrane permeability of yeast cells subjected to ethanol stress.
authors.affiliation: Department of Biological Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Chun-Keng
authors.initials: CK
authors.lastname: Hu
authors.forename: Feng-Wu
authors.initials: FW
authors.lastname: Bai
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: An
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012568:Schizosaccharomyces / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013696:Temperature
chemical_list: D000431:Ethanol; D002118:Calcium