INSIBIO   05451
INSTITUTO SUPERIOR DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Regulation by metals of phosphate-dependent ndh expression in Escherichia coli
Autor/es:
MARIANA GRILLO-PUERTAS; LICI A. SCHURIG-BRICCIO; LUISA RODRÍGUEZ-MONTELONGO; MARÍA R. RINTOUL; VIVIANA A. RAPISARDA
Lugar:
Villa Carlos Paz (Córdoba)
Reunión:
Congreso; Reunión anual SAIB; 2008
Institución organizadora:
SAIB
Resumen:
The ndh gene, which codified NADH dehydrogenase-2 in E. coli, is
highly regulated at transcriptional level by diverse external stimuli.
Our laboratory reported that ndh expression was maintained in
stationary phase when cells were grown in the presence of at least 37
mM phosphate. Preliminary observations also indicated that ndh
expression was decreased when cells were grown in the presence of
copper. The aim of this work was to study the regulation of
phosphate-dependent ndh expression during stationary phase by
transition metals. The experiments were performed using
chromosomal fusions of the complete promoter or its deletions with
lacZ. A concentrations range of Cu2+ was added at different times of
growth. b-Galactosidase activity and viability were determined. In
exponential phase cells, ndh expression was not regulated by copper.
However, during stationary phase, the phosphate-dependent gene
expression was totally repressed when cells were incubated for 1 h
with 1 mM CuSO . This copper effect was also observed with ndh 4
promoter deletions from -250 to -100. Viability was not modified in
any of the conditions tested. To analyze a possible copper-specific
ndh repression, others metals that regulate metal-responsive
promoters were assayed. Further studies should be done to elucidate
this metal-mediated regulation of ndh during stationary phase.