title: Protective effect of ions against cell death induced by acid stress in Saccharomyces.
abstract: Saccharomyces boulardii is a probiotic used to prevent or treat antibiotic-induced gastrointestinal disorders and acute enteritis. For probiotics to be effective they must first be able to survive the harsh gastrointestinal environment. In this work, we show that S. boulardii displayed the greatest tolerance to simulated gastric environments compared with several Saccharomyces cerevisiae strains tested. Under these conditions, a pH 2.0 was the main factor responsible for decreased cell viability. Importantly, the addition of low concentrations of sodium chloride (NaCl) protected cells in acidic conditions more effectively than other salts. In the absence of S. boulardii mutants, the protective effects of Na(+) in yeast viability in acidic conditions was tested using S. cerevisiae Na(+)-ATPases (ena1-4), Na(+)/H(+) antiporter (nha1Delta) and Na(+)/H(+) antiporter prevacuolar (nhx1Delta) null mutants, respectively. Moreover, we provide evidence suggesting that this protection is determined by the plasma membrane potential, once altered by low pH and low NaCl concentrations. Additionally, the absence or low expression/activity of Ena proteins seems to be closely related to the basal membrane potential of the cells.
authors.affiliation: Laboratório de Biologia Celular e Molecular (LBCM), Núcleo de Pesquisa em Ciências Biológicas, Departamento de Farmácia, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
authors.forename: Gilzeane dos Santos
authors.initials: GS
authors.lastname: Sant'Ana
authors.forename: Lisvane da Silva
authors.initials: LS
authors.lastname: Paes
authors.forename: Argentino F Vieira
authors.initials: AF
authors.lastname: Paiva
authors.forename: Luciano Gomes
authors.initials: LG
authors.lastname: Fietto
authors.forename: Antônio Helvécio
authors.initials: AH
authors.lastname: Totola
authors.forename: Maria J Magalhães
authors.initials: MJ
authors.lastname: Trópia
authors.forename: Denise
authors.initials: D
authors.lastname: Silveira-Lemos
authors.forename: Cândida
authors.initials: C
authors.lastname: Lucas
authors.forename: Juliana L Rangel
authors.initials: JL
authors.lastname: Fietto
authors.forename: Rogelio L
authors.initials: RL
authors.lastname: Brandão
authors.forename: Ieso de Miranda
authors.initials: IM
authors.lastname: Castro
mesh_terms: D000143:Acids / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D016923:Cell Death; D017353:Gene Deletion; D005800:Genes, Fungal; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000378:metabolism*; D050296:Microbial Viability; D017494:Proton Pumps / Q000378:metabolism; D012440:Saccharomyces / Q000187:drug effects* / Q000502:physiology*; D013312:Stress, Physiological
chemical_list: D000143:Acids; D000935:Antifungal Agents; D007477:Ions; D017494:Proton Pumps