title: Interactions of Condensed Tannins with Saccharomyces cerevisiae Yeast Cells and Cell Walls: Tannin Location by Microscopy.
abstract: Interactions between grape tannins/red wine polyphenols and yeast cells/cell walls was previously studied within the framework of red wine aging and the use of yeast-derived products as an alternative to aging on lees. Results evidenced a quite different behavior between whole cells (biomass grown to elaborate yeast-derived products, inactivated yeast, and yeast inactivated after autolysis) and yeast cell walls (obtained from mechanical disruption of the biomass). Briefly, whole cells exhibited a high capacity to irreversibly adsorb grape and wine tannins, whereas only weak interactions were observed for cell walls. This last point was quite unexpected considering the literature and called into question the real role of cell walls in yeasts' ability to fix tannins. In the present work, tannin location after interactions between grape and wine tannins and yeast cells and cell walls was studied by means of transmission electron microscopy, light epifluorescence, and confocal microscopy. Microscopy observations evidenced that if tannins interact with cell walls, and especially cell wall mannoproteins, they also diffuse freely through the walls of dead cells to interact with their plasma membrane and cytoplasmic components.
authors.affiliation: INRA, UMR 1083 SPO, F-34060 Montpellier, France.|Montpellier SupAgro, UMR 1083 SPO, F-34060 Montpellier, France.|Université Montpellier 1, UMR 1083 SPO, F-34060 Montpellier, France.|Lallemand SAS, 19 rue des Briquetiers, B.P. 59, 31702 Blagnac, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Mekoue Nguela
authors.affiliation: INRA, UMR 1083 SPO, F-34060 Montpellier, France.|Montpellier SupAgro, UMR 1083 SPO, F-34060 Montpellier, France.|Université Montpellier 1, UMR 1083 SPO, F-34060 Montpellier, France.
authors.forename: Aude
authors.initials: A
authors.lastname: Vernhet
authors.affiliation: Lallemand SAS, 19 rue des Briquetiers, B.P. 59, 31702 Blagnac, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sieczkowski
authors.affiliation: INRA, UMR 1083 SPO, F-34060 Montpellier, France.|Montpellier SupAgro, UMR 1083 SPO, F-34060 Montpellier, France.|Université Montpellier 1, UMR 1083 SPO, F-34060 Montpellier, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Brillouet
mesh_terms: D001692:Biological Transport; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism*; D008853:Microscopy; D044945:Proanthocyanidins / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000378:metabolism*
chemical_list: D044945:Proanthocyanidins
keywords: Saccharomyces cerevisiae; cell wall mannoproteins; condensed tannins; cytoplasmic proteins; interactions; microscopy