• Title of article

    Involvement of osmotic cell shrinkage on the proton extrusion rate in Saccharomyces cerevisiae

  • Author/Authors

    Martيnez de Maraٌَn، نويسنده , , Iٌigo and Tourdot-Marechal، نويسنده , , Raphaëlle and Gervais، نويسنده , , Patrick، نويسنده ,

  • Issue Information
    روزنامه با شماره پیاپی سال 2001
  • Pages
    6
  • From page
    241
  • To page
    246
  • Abstract
    Saccharomyces cerevisiae has been subjected to hyperosmotic shocks by using permeating (sorbitol, xylitol, glycerol, NaCl) and nonpermeating (PEG 600) solutes. The proton extrusion rate decreased as the osmotic pressure increased, whichever solute was used. However, the total inhibition of the cellular H+ extrusion depended on the solute used. A total inhibition was observed at about 20 MPa with glycerol, xylitol and sorbitol. With PEG 600, a total inhibition of extracellular acidification was obtained at 8.5 MPa. NaCl, with an extracellular pressure of 37.8 MPa (near saturation), did not completely inhibit the extracellular acidification. These results showed that the total inhibition of proton extrusion, involving probably the membrane H+-ATPase, was not correlated to the hydric state of the external medium but was strictly linked to the degree of permeation of solutes across the plasma membrane. The extracellular acidification was totally inhibited by a critical final cell volume reached after the osmotic shrinkage, whichever solute was used. This critical final cell volume represented 50% of the initial cell volume. This result suggests that the final cell volume reached after an osmotic stress represents a key thermodynamic parameter for cell osmoregulation in which H+-ATPase would be implicated.
  • Keywords
    Solute permeability , Critical cell volume , Osmotic pressure , Proton extrusion rate
  • Journal title
    International Journal of Food Microbiology
  • Serial Year
    2001
  • Journal title
    International Journal of Food Microbiology
  • Record number

    2109211