CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Cloning and expresión of a bile salts hydrolase gene from Lactobacillus reuteri CRL 1098.
Autor/es:
BUSTOS A. Y.; FONT DE VALDEZ G.; RAYA R.; TARANTO M.P.
Lugar:
Villa Carlos Paz. Córdoba
Reunión:
Congreso; XLIV Reunion Annual-Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular (SAIB); 2008
Resumen:
Bile acids (BA) are biological detergents that play an essential role in fat digestion. They are synthesized from cholesterol in the liver and then released into the intestines, where may be extensively modified by the indigenous intestinal bacteria. Microbial Bile Salt  Hydrolase (BSH) is an important enzyme that hydrolizes the amide bond of the glycine/taurine moiety of BA from the steroid core. A close relationship has been demonstrated between BSH and the ability of the sourdough isolate Lactobacillus (L.) reuteri CRL 1098 to remove cholesterol in vitro. In this work, the hsb gene from this strain was amplified by PCR techniques. The deduced sequence was shown to have 99% similarity with a choloylglycine hydrolase from L. reuteri F275. The hsb gene with its putative promotor region was cloned and expressed in Escherichia coli DH 10b and Lactococcus lactis NZ9000. L. lactis NZ9000 (BSH+) cell free extracts (CFE) showed BSH activity towards all BA assayed (5 mM of GDCA, TDCA, GCA or TCA). For some BA, the BSH values were similar or even higher than those detected in the wild-type L. reuteri CRL 1098. In particular, higher values were observed towards GDCA in boths strains. These results confirmed the functionality of the hsb gene of L. reuteri CRL 1098 and will contribute to the knowledge of BA metabolism in probiotic microorganisms.