INVESTIGADORES
RAPISARDA Viviana Andrea
congresos y reuniones científicas
Título:
Oxidative shift in late stationary phase by phosphate concentrations in Escherichia coli
Autor/es:
SCHURIG-BRICCIO, L. A.; RINTOUL, M. R.; RODRÍGUEZ-MONTELONGO, L.; RAPISARDA, V. A.
Lugar:
Mar del Plata
Reunión:
Congreso; XLIII Reunión Anual de SAIB; 2007
Institución organizadora:
SAIB
Resumen:
  Respiratory NADH dehydrogenase-2 (NDH-2) in Escherichia coli is a cupric-reductase encoded by ndh gene. This gene is expressed in LB medium during exponential phase of growth, decaying in stationary phase. However, we found that ndh expression and NDH-2 membrane activity are maintained in late stationary phase by at least 35 mM phosphate salts. In order to study the cellular status in this physiological condition, we determined cell viability, oxygen consumption, NADH and NAD+ concentration and ROS production. Cells grown for 48 h in high phosphate media were more viable, presented higher oxygen consumption, had a lower NADH/NAD+ ratio (similar to exponential) and contained lower ROS levels than cells grown in low phosphate media. Moreover, we have observed that the decrease of ndh expression in low phosphate media was reversible when phosphate was added at 24h of culture. Our results show the importance of the phosphate concentration in the culture media for the regulation of genes expression, since modifications in the anion concentration can produce a drastic change in the cellular metabolic pathways maybe associated to a protective effect against oxidative stress. Further studies should be done to understand the role of NDH-2 in late stationary phase under this growth condition.