title: Cell envelope changes in Bifidobacterium animalis ssp. lactis as a response to bile.
abstract: Bifidobacterium animalis ssp. lactis is a probiotic frequently used as adjunct culture in fermented dairy products. In order to ensure its proper function at the intestinal level, this bacterium has to be tolerant to physiological concentrations of bile. This study examined the influence of bile on the fatty acid composition and the membrane characteristics of B. animalis IPLA 4549 and its mutant with acquired resistance to bile, B. animalis 4549dOx. Bile adaptation triggers in B. animalis 4549dOx a decrease in membrane fluidity and in the protein : phospholipid ratio, as well as a shift in the fatty acid composition of the cell. Remarkably, the presence of bile in the growth medium induced similar changes in both B. animalis cells. Furthermore, transmission electron microscopy analysis showed that bile promotes a severe distortion of the cell surface. This study provides new insights of the action of bile on the cell envelope of bifidobacteria.
authors.affiliation: Departamento de Microbiología y Bioquímica de Productos Lácteos, Consejo Superior de Investigaciones Científicas, Villaviciosa, Asturias, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Ruiz
authors.forename: Borja
authors.initials: B
authors.lastname: Sánchez
authors.forename: Patricia
authors.initials: P
authors.lastname: Ruas-Madiedo
authors.forename: Clara G
authors.initials: CG
authors.lastname: de Los Reyes-Gavilán
authors.forename: Abelardo
authors.initials: A
authors.lastname: Margolles
mesh_terms: D001644:Bifidobacterium / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D001646:Bile / Q000737:chemistry* / Q000378:metabolism; D001647:Bile Acids and Salts / Q000378:metabolism / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry; D005227:Fatty Acids / Q000096:biosynthesis / Q000378:metabolism; D008854:Microscopy, Electron; D019936:Probiotics
chemical_list: D001647:Bile Acids and Salts; D005227:Fatty Acids