[Todos] Recordatorio seminario lunes 17 de noviembre

[Cybele García]

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>> Seminarios del Departamento de Quimica Biologica
>> Aula del Departamento de Quimica Biologica, 4to piso
>> Todos los Lunes a las 13 horas.
>> Fecha: Lunes 17 de noviembre

>> Expositor:  Lic. Mariano Prado,
Laboratorio de estudios de estrés osmótico en bacterias Gram positivas,
Dto. Qca. Biológica, FCEyN, UBA

"Función de la proteina S-layer de Lactobacillus acidophilus "

Lactobacillus acidophilus is one of the major species of the genus
Lactobacillus found in human and animal intestines and believed to possess
probiotic properties. In the outermost envelope of Lb. acidophilus ATCC
4356, an S-layer structure is found. It is composed of 45Kb protein
monomers encoded by a slpA gene. The activity of this S-layer was assayed
against Salmonella newport as a pathogen model. SDS-PAGE electrophoresis
of the S-layer and zymogram analysis with cell-wall extracted from
Salmonella newport as substrate revealed a true uncharacterized lytic
activity coincident with that identified by western blot. This activity
was also observed with both cell wall and whole cells. The analysis of the
peptidoglycan breakage products showed an increase of free amino-acids
suggesting that this S-layer acts as an endopeptidase. The activity was
not detected against Bacillus and Lactobacillus cell walls. This gene was
sequenced and showed 99% homology with other slpA from Lb. acidophilus
strains and in silico analysis of the deduced protein showed a C-terminal
motif which aligned with murein hydrolases of several Lactobacillus
strains. The C-terminal motif was cloned and expressed in Bacillus
subtilis where it conserved the murein hydrolase activity.  The new
activity here described may contribute to the already reported probiotic
properties of this bacterium.


>> Los esperamos
>> Cybele Garcia
>> Martin Monte
>> Departamento de Química Biológica
>> Facultad de Ciencias Exactas y Naturales
>> Universidad de Buenos Aires
>> Ciudad Universitaria
>> Ciudad de Buenos Aires - Argentina