Producción CyT
Biocell - CodY and DtpT are involved in the modulation of prtP during osmotic stress in Lactobacillus casei.
Congreso
Fecha:
2005Editorial y Lugar de Edición:
SAIBISSN:
0327-9545Resumen *
Components of the proteolytic system of Lactic Acid Bacteria (LAB) play an important role in the development of flavor in fermented food. Moreover addition of salt is commonly used in several industrial processes using these bacteria. We have demonstrated the role of peptides in the adaptation to high salt in Lactobacillus casei; the transcription activity of the prtP gene (codifying for the major proteolytic activity) was repressed by peptides but this repression failed in NaCl (Piuri et al 2003, JAM 95:372). The expression of PrtP has been linked to the peptide and oligopeptide transport systems dpp, dtp and opp. In this work we analyzed the behavior of a dtpT mutant, codifying for one of the peptide transporters present in the membrane of Lb. casei, during growth in high salt media. This mutant showed an osmosensitive phenotype and peptides preferentially transported by this protein failed to improve the growth of this bacterium in high salted medium. We verified the presence of the pleiotropic regulator CodY in this bacteria. A direct interaction between this regulator and the prtP promoter was shown by using in vitro electrophoretic mobility shift assays and Chromatin immunoprecipitation (ChIP-to-chip) experiments. These results suggest that CodY could mediate the lost of repression observed in a NaCl containing medium, even in the presence of peptides consistent with a decreased level of intracellular branched-chain aminoacids (BCAA). Información suministrada por el agente en SIGEVAPalabras Clave
prtPDtpTCodYLactobacillus casei