title: Efflux of bile acids in Lactobacillus reuteri is mediated by ATP.
abstract: To study whether an active bile acid (BA) efflux occurs in Lactobacillus reuteri CRL 1098 as well as the nature (ATP or proton motive force [PMF] mediated primary transport) of the BA extrusion mechanism.                         BAs are powerful detergents which disorganize the lipid bilayer structure of cellular membranes. Specific bile resistance mechanisms (bile efflux, bile salt hydrolysis, and intrinsic architecture and composition of cell membrane the most prevalent) have been described in intestinal bacteria. L. reuteri, showed a significant degree of resistance to the toxic action of BA and the presence of an active efflux ATP-dependent of conjugated (taurocholic [TCA]) and free (cholic [CA]) BA in the CRL 1098 strain is now reported. However, due the high pKa (5.5) of cholic acid (CA) compared with the conjugated species, a significant fraction (between 35 and 50% at pH 6.5 and 5.2, respectively) of free BA also diffused passively, even in the absence of ATP. To our knowledge, our results represent the first evidence of ATP as the energy source involved in the BA extrusion in L. reuteri.
authors: Centro de Referencia para Lactobacilos (CERELA-CONICET)-Chacabuco 145 (T4000ILC), San Miguel de Tucumán, Argentina.
authors: Ana Yanina
authors: AY
authors: Bustos
authors: Raúl
authors: R
authors: Raya
authors: Graciela Font
authors: GF
authors: de Valdez
authors: María Pía
authors: MP
authors: Taranto
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D001693:Biological Transport, Active; D019826:Cholic Acid / Q000378:metabolism* / Q000633:toxicity; D052200:Limosilactobacillus reuteri / Q000187:drug effects / Q000378:metabolism*; D013656:Taurocholic Acid / Q000378:metabolism* / Q000633:toxicity
chemical_list: D013656:Taurocholic Acid; D000255:Adenosine Triphosphate; D019826:Cholic Acid