INLAIN   20354
INSTITUTO DE LACTOLOGIA INDUSTRIAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
AN INSIGHT INTO THE ADAPTATION OF L. delbrueckii subsp. lactis 200 TO THE INTESTINAL ENVIRONMENT.
Autor/es:
BURNS, P.; SÁNCHEZ, B.; VINDEROLA, G; RUIZ, L.; RUAS-MADIEDO, P.; MARGOLLES, A.; REINHEIMER, J.; DE LOS REYES-GAVILÁN, C.
Lugar:
Tucumán
Reunión:
Simposio; III Simposio Internacional de Bacterias Lácticas. II Encuentro Red BAL Argentina; 2009
Resumen:
Selected Lactobacillus delbrueckii strains are intensively used in the fermentative dairy industry for the production of fermented milks or cheeses. They have a limited capacity to overcome the gastrointestinal barriers since they are not of intestinal origin. In a previous work, we adapted the autoaggregative strain L. delbrueckii subsp. lactis 200 to physiological concentrations of bile salts (BS) by exposures to increasing concentrations up to 0.5% (w/v). In this work, we aimed at characterizing the adaptation of this strain and its bile-resistant derivative (BRD) to the intestinal environment. We studied 1) the effects of the exposure and adaptation to BS on the expression of cytosolic proteins by a proteomic approach; 2) the capacity of survival to the intestinal transit in vitro and ex vivo (using filter-sterilized mouse intestinal fluid); 3) the growth capacity in the presence of individual bile acids; 4) the cell surface hydrophobicity; 5) the autoaggregation capacity; 6) the adhesion capacity to the HT-29-MTX intestinal cell line and 7) the interaction with the small intestine of FITC-labelled (fluorescent) bacteria after 10 and 30 min of their oral administration (108 CFU) to mice. The proteomic study revealed an activation of the glycolysis favouring the formation of lactate, mainly in the BRD. These changes may represent a mechanism of active generation of energy to face the stress imposed by BS. No differences were detected in the in vitro resistance to the intestinal transit between the parent and the BRD. However, when the intestinal fluid was used, the BRD showed a higher resistance than the parent strain as well as the capacity to grow in the presence of some bile acids. The hydrophobicity of the parent strain (70 ± 0.9 %) significantly diminished for the BRD (20 ± 0.6%) in the presence of BS. The autoaggregation capacity and the adhesion to the cell line also diminished in the presence of BS which correlated (proteomic study) with a down-regulation of the expression of the elongation factor Tu, a molecule that mediates cell adhesion to the intestinal mucosa. In the study of the interaction with the small intestine (FITC-labeled bacteria), cellular aggregates of the parent strain were observed in the lumen as well as cells attached to the gut epithelium. For the BRD, fluorescent points were observed internalized in the lamina propria. This fact additionally evidences, in vivo, a loss in the adhesion capacity for the BRD. The adaptation to physiological concentrations of bile salts conferred the strain a higher survival capacity in the intestinal environment. However, it also induced a loss in the hydrophobicity and in the autoaggregation and adhesion capacities. The impact of these changes on the gut immune response must still be determined in a murine model.