[Todos] Recordatorio seminario lunes 24 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 24 de noviembre

>> Expositor:  Lic. Pablo Iván Nikel
Instituto de Investigaciones Biotecnológicas
UNSAM-CONICET
INTI



*Metabolic flux analysis of Escherichia coli creB and arcA mutants*


*Escherichia coli* has several complex sensing mechanisms for response to
carbon availability and oxygen levels. Among them, the two-component
signal transduction systems CreBC and ArcAB are responsible for regulation
of carbon catabolism and transition from oxidative to fermentative
metabolism, respectively. To systematically investigate the contribution
of CreB- and ArcA-dependent regulation in catabolism, glucose-limited
chemostat cultures were conducted for a wild-type strain, ¦¤*creB* and
¦¤*arcA* single mutants, and a ¦¤*creB* ¦¤*arcA* double mutant under a
well-defined microaerobic condition. Metabolic flux distributions of the
cultures of these strains were estimated based on 13C labeling
experiments. It was shown that the oxidative pentose phosphate pathway was
functioning at low level under semi-aerobic conditions for the mutant
strains. Fluxes through pyruvate dehydrogenase and the tricarboxylic acid
cycle were found to be lower in the mutants, while that of the glyoxylate
shunt was higher for the
*arcA*strain. Strains bearing the
*creB* mutation achieved a higher biomass yield on glucose than that of
the wild-type strain or the *arcA* single mutant. Accordingly, the fluxes
towards biomass were higher for those strains. Taken together, these
results show that the CreBC and ArcAB systems operate in a concerted
fashion to provide a fine tuning in the central metabolic pathways of *E*.
*coli*.





>> 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