ENTEROBACTIN ROLE IN Escherichia coli OXIDATIVE STRESS RESPONSE

PERALTA, DAIANA; ADLER, CONRADO; CORBALAN, NATALIA; PAZ GARCÍA, ENRIQUE CARLOS; POMARES, FERNANDA; VINCENT, PAULA

Congreso; SAIB; 2014

Alternative roles for siderophores might explain the potential adaptive advantages of microorganisms having multiplesiderophore systems. Escherichia coli synthesizes the catechol siderophore enterobactin and has up to nine irontransport systems, most of them involving heterologous siderophore-iron complexes. We previously reported therequirement of enterobactin for E. coli colony development in minimal media (M9) and we associate this phenotypewith an increment in oxidative stress. Now, we analyzed the role of enterobactin in reducing cell oxidative stress. Weshowed that entE expression increased in cells growing in M9 and in presence of oxidative agents but decline whenascorbic 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 thestress-sensitivity. Furthermore, we found that total catalase activity decreased in entE cells growing in M9 andaddition of catalase to the media restored colony growth of an entE mutant. Finally, we demonstrated thatenterobactin exhibited in vitro, high radical scavenging activity against DPPH. These results suggest that enterobactincould be an important piece in the oxidative stress response of E. coli, particularly required in the context of colonydevelopment in M9.