title: Combined cold, acid, ethanol shocks in Oenococcus oeni: effects on membrane fluidity and cell viability.
abstract: The effects of combined cold, acid and ethanol on the membrane physical state and on the survival of Oenococcus oeni were investigated. Membrane fluidity was monitored on intact whole O. oeni cells subjected to single and combined cold, acid and ethanol shocks by using fluorescence anisotropy with 1,6-diphenyl-1,3,5-hexatriene (DPH) as a probe. Results showed that cold shocks (14 and 8 degrees C) strongly rigidified plasma membrane but did not affect cell survival. In contrast, ethanol shocks (10-14% v/v) induced instantaneous membrane fluidisation followed by rigidification and resulted in low viability. Acid shocks (pH 4.0 and pH 3.0) exerted a rigidifying effect on membrane without affecting cell viability. Whatever the shock orders, combined cold (14 degrees C) and ethanol (14% v/v) shocks resulted in strong membrane rigidification. Interestingly, O. oeni survived combined cold and ethanol shocks more efficiently than single ethanol shock. Membrane rigidification was induced by ethanol-and-acid (10% v/v - pH 3.5) shock and correlated with total cell death. In contrast, O. oeni recovered its viability when subjected to cold (8 degrees C)-then-ethanol-and-acid shock which strongly rigidified the membrane. Our results suggested a positive short-term effect of combined cold, acid and ethanol shocks on membrane fluidity and viability of O. oeni.
authors.affiliation: Laboratoire de Microbiologie UMR UB/INRA 1232, équipe PG2MA, Ecole Nationale de Biologie Appliquée à la Nutrition et à l'Alimentation (ENSBANA), 1 esplanade Erasme, F-21000 Dijon, France.
authors.forename: Son
authors.initials: S
authors.lastname: Chu-Ky
authors.forename: Raphaëlle
authors.initials: R
authors.lastname: Tourdot-Marechal
authors.forename: Pierre-André
authors.initials: PA
authors.lastname: Marechal
authors.forename: Jean
authors.initials: J
authors.lastname: Guzzo
mesh_terms: D000143:Acids / Q000494:pharmacology; D003080:Cold Temperature; D004161:Diphenylhexatriene / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D005456:Fluorescent Dyes / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007777:Lactobacillaceae / Q000378:metabolism*; D008560:Membrane Fluidity / Q000187:drug effects*; D012997:Solvents / Q000494:pharmacology*
chemical_list: D000143:Acids; D005456:Fluorescent Dyes; D012997:Solvents; D004161:Diphenylhexatriene; D000431:Ethanol