title: Changes in membrane lipid composition in ethanol- and acid-adapted Oenococcus oeni cells: characterization of the cfa gene by heterologous complementation.
abstract: Cyclopropane fatty acid (CFA) synthesis was investigated in Oenococcus oeni. The data obtained demonstrated that acid-grown cells or cells harvested in the stationary growth phase showed changes in fatty acid composition similar to those of ethanol-grown cells. An increase of the CFA content and a decrease of the oleic acid content were observed. The biosynthesis of CFAs from unsaturated fatty acid phospholipids is catalysed by CFA synthases. Quantitative real-time-PCR experiments were performed on the cfa gene of O. oeni, which encodes a putative CFA synthase. The level of cfa transcripts increased when cells were harvested in stationary phase and when cells were grown in the presence of ethanol or at low pH, suggesting transcriptional regulation of the cfa gene under different stress conditions. In contrast to Escherichia coli, only one functional promoter was identified upstream of the cfa gene of O. oeni. The function of the cfa gene was confirmed by complementation of a cfa-deficient E. coli strain. Nevertheless, the complementation remained partial because the conversion percentage of unsaturated fatty acids into CFA of the complemented strain was much lower than that of the wild-type strain. Moreover, a prevalence of cycC19 : 0 was observed in the membrane of the complemented strain. This could be due to a specific affinity of the CFA synthase from O. oeni. In spite of this partial complementation, the complemented strain of E. coli totally recovered its viability after ethanol shock (10 %, v/v) whereas its viability was only partly recovered after an acid shock at pH 3.0.
authors.affiliation: Laboratoire Recherche en Vigne et Vin, Université de Bourgogne, Institut Universitaire de la Vigne et du Vin Jules Guyot, 1, Rue Claude Ladrey - Campus Montmuzard, BP27877, F-21078 Dijon, France.
authors.forename: Cosette
authors.initials: C
authors.lastname: Grandvalet
authors.affiliation: Laboratoire Recherche en Vigne et Vin, Université de Bourgogne, Institut Universitaire de la Vigne et du Vin Jules Guyot, 1, Rue Claude Ladrey - Campus Montmuzard, BP27877, F-21078 Dijon, France.
authors.forename: Juan Simón
authors.initials: JS
authors.lastname: Assad-García
authors.affiliation: Laboratoire Recherche en Vigne et Vin, Université de Bourgogne, Institut Universitaire de la Vigne et du Vin Jules Guyot, 1, Rue Claude Ladrey - Campus Montmuzard, BP27877, F-21078 Dijon, France.
authors.forename: Son
authors.initials: S
authors.lastname: Chu-Ky
authors.affiliation: Laboratoire Recherche en Vigne et Vin, Université de Bourgogne, Institut Universitaire de la Vigne et du Vin Jules Guyot, 1, Rue Claude Ladrey - Campus Montmuzard, BP27877, F-21078 Dijon, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Tollot
authors.affiliation: Laboratoire Recherche en Vigne et Vin, Université de Bourgogne, Institut Universitaire de la Vigne et du Vin Jules Guyot, 1, Rue Claude Ladrey - Campus Montmuzard, BP27877, F-21078 Dijon, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Guzzo
authors.affiliation: UMR 866 Equipe Physiopathologie des Dyslipidémies, Faculté des Sciences Gabriel, 6, Bd Gabriel, F-21000 Dijon, France.
authors.forename: Joseph
authors.initials: J
authors.lastname: Gresti
authors.affiliation: Laboratoire Recherche en Vigne et Vin, Université de Bourgogne, Institut Universitaire de la Vigne et du Vin Jules Guyot, 1, Rue Claude Ladrey - Campus Montmuzard, BP27877, F-21078 Dijon, France.
authors.forename: Raphaëlle
authors.initials: R
authors.lastname: Tourdot-Maréchal