ENTEROBACTIN ROLE IN Escherichia coli OXIDATIVE STRESS RESPONSE

PERALTA DR, ADLER C, CORBALÁN NS, PAZ EC, POMARES MF, VINCENT PA

Rosario

Congreso; 2014, L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Alternative roles for siderophores might explain the potential adaptive advantages of microorganisms having multiple siderophore systems. Escherichia coli synthesizes the catechol siderophore enterobactin and has up to nine iron transport systems, most of them involving heterologous siderophore-iron complexes. We previously reported the requirement of enterobactin for E. coli colony development in minimal media (M9) and we associate this phenotype with an increment in oxidative stress. Now, we analyzed the role of enterobactin in reducing cell oxidative stress. We showed that entE expression increased in cells growing in M9 and in presence of oxidative agents but decline when ascorbic acid was added. Also, we observed that the lack of enterobactin increased H202 and Paraquat cell sensitivity. The addition of enterobactin to the media protected cells and different levels of iron availability did not impact on the stress-sensitivity. Furthermore, we found that total catalase activity decreased in entE cells growing in M9 and addition of catalase to the media restored colony growth of an entE mutant. Finally, we demonstrated that enterobactin exhibited in vitro, high radical scavenging activity against DPPH. These results suggest that enterobactin could be an important piece in the oxidative stress response of E. coli, particularly required in the context of colony development in M9.