INVESTIGADORES
ADLER Conrado
artículos
Título:
Enterobactin as Part of the Oxidative Stress Response Repertoire
Autor/es:
PERALTA, DAIANA; ADLER, CONRADO; CORBALAN, NATALIA; PAZ GARCÍA, ENRIQUE CARLOS; POMARES, FERNANDA; VINCENT, PAULA
Revista:
PLOS ONE
Editorial:
PUBLIC LIBRARY SCIENCE
Referencias:
Lugar: San Francisco; Año: 2016
ISSN:
1932-6203
Resumen:
Microorganisms produce siderophores to facilitate iron uptake and even though this traithas been extensively studied, there is growing evidence suggesting that siderophores mayhave other physiological roles aside from iron acquisition. In support of this notion, we previouslylinked the archetypal siderophore enterobactin with oxidative stress alleviation. To furthercharacterize this association, we studied the sensitivity of Escherichia coli strainslacking different components of the enterobactin system to the classical oxidative stressorshydrogen peroxide and paraquat. We observed that strains impaired in enterobactin production,uptake and hydrolysis were more susceptible to the oxidative damage caused byboth compounds than the wild-type strain. In addition, meanwhile iron supplementation hadlittle impact on the sensitivity, the reducing agent ascorbic acid alleviated the oxidativestress and therefore significantly decreased the sensitivity to the stressors. This indicatedthat the enterobactin-mediated protection is independent of its ability to scavenge iron. Furthermore,enterobactin supplementation conferred resistance to the entE mutant but did nothave any protective effect on the fepG and fes mutants. Thus, we inferred that only afterenterobactin is hydrolysed by Fes in the cell cytoplasm and iron is released, the freehydroxyl groups are available for radical stabilization. This hypothesis was validated testingthe ability of enterobactin to scavenge radicals in vitro. Given the strong connectionbetween enterobactin and oxidative stress, we studied the transcription of the entE geneand the concomitant production of the siderophore in response to such kind of stress. Interestingly,we observed that meanwhile iron represses the expression and production of thesiderophore, hydrogen peroxide and paraquat favour these events even if iron is present.Our results support the involvement of enterobactin as part of the oxidative stress responseand highlight the existence of a novel regulation mechanism for enterobactin biosynthesis.