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Biochem Biophys Res Commun ; 458(1): 46-51, 2015 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-25637663

RESUMEN

It has been proposed that some antibiotics exert additional damage through reactive oxygen species (ROS) production. Since H2S protects neurons and cardiac muscle from oxidative stress, it has been hypothesized that bacterial H2S might, similarly, be a cellular protector against antibiotics. In Enterobacteriaceae, H2S can be produced by the cysJIH pathway, which uses sulfate as the sulfur source. CysB, in turn, is a positive regulator of cysJIH. At present, the role of S. Typhimurium cysJIH operon in the protection to reactive oxygen species (ROS) induced by antimicrobial compounds remains to be elucidated. In this work, we evaluated the role of cysJIH and cysB in ROS accumulation, superoxide dismutase (SOD) activity, reduced thiol accumulation, and H2S accumulation in S. Typhimurium, cultured in either sulfate or cysteine as the sole sulfur source. Furthermore, we assessed the effects of the addition of ceftriaxone (CEF) and menadione (MEN) in these same parameters. In sulfate as the sole sulfur source, we found that the cysJIH operon and the cysB gene were required to full growth in minimal media, independently on the addition of CEF or MEN. Most importantly, both cysJIH and cysB contributed to diminish ROS levels, increase the SOD activity, increase the reduced thiols, and increase the H2S levels in presence of CEF or MEN. Moreover, the cysJIH operon exhibited a CysB-dependent upregulation in presence of these two antimicrobials compounds. On the other hand, when cysteine was used as the sole sulfur source, we found that cysJIH operon was completely negligible, were only cysB exhibited similar phenotypes than the described for sulfate as sulfur source. Unexpectedly, CysB downregulated cysJIH operon when cysteine was used instead of sulfate, suggesting a complex regulation of this system.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/genética , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Ceftriaxona/farmacología , Medios de Cultivo/química , Medios de Cultivo/farmacología , Eliminación de Gen , Sulfuro de Hidrógeno/metabolismo , Datos de Secuencia Molecular , Operón/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Salmonella typhimurium/crecimiento & desarrollo , Salmonella typhimurium/metabolismo , Sulfatos/metabolismo , Sulfito Reductasa (NADPH)/genética , Sulfito Reductasa (NADPH)/metabolismo , Superóxido Dismutasa/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Vitamina K 3/farmacología
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