INSTITUTO DE LACTOLOGIA INDUSTRIAL
Unidad Ejecutora - UE
Inside the adaptation process of Lactobacillus delbrueckii subsp. lactis to bile
BURNS, P.; SANCHEZ B.; VINDEROLA, G.; RUAS-MADIEDO, P.; MARGOLLES A.; REINHEIMER, J.A.; C.G. DE LOS REYES-GAVILAN
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
ELSEVIER SCIENCE BV
Año: 2010 vol. 142 p. 132 - 132
The process of progressive adaptation to bile might confer to some non-intestinal dairy lactobacilli the capacity to grow under physiological concentrations of bile salts, which might be a valuable tool for increasing the survival of non-intestinal dairy lactobacilli in the gastrointestinal ecosystem. In a previous study, we adapted L. delbrueckii subsp. lactis 200, a highly autoaggregative strain isolated from natural whey starters in Argentina, to physiological concentrations of bile salts. In the present work, we studied changes in the production of cytosolic proteins by L. delbrueckii subsp. lactis 200 and its bile resistant derivative L. delbrueckii subsp. lactis 200+ following exposure to bile salts, and the influence of bile on the survival of these microorganisms to in vitro simulated gastrointestinal conditions. The comparison of the parental and bile resistant strains allowed us to underline the resistance mechanisms acquired by the derivative and the response to bile in L. delbrueckii subsp. lactis. Significant differences in the level of metabolic end products of the catabolism of carbohydrates as well as in the in vitro adhesion capability to intestinal cell lines were found between parental and bile resistant derivative strains, which correlated with some differences found between both proteomes. In vitro exposure to simulated gastrointestinal conditions indicated that milk can exert a protective effect on L. delbrueckii subsp. lactis allowing its survival to simulated gastric and intestinal juices whereas growth in the presence of bile prevented the adhesion of microorganisms to intestinal cell lines. These results indicated that adaptation and response to bile in L. delbrueckii subsp. lactis involve several physiological mechanisms that are focused to minimize the deleterious impact of bile salts on cell`s physiology. Bile can also prevent the adhesion of living microorganisms that arrive protected by foods to the small intestine where the concentration of bile is high, thus facilitating the adhesion in more distal parts of the gut where bile concentrations are low.