The relationship between the transcriptional regulator RpoS with the virulence and nutritional competence of enteropathogenic Escherichia coli

• Grant number: 13/01014-5
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2013
• End date: May 31, 2015
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Beny Spira
• Grantee: Gardênia Márcia Silva Campos Mata
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Enteropathogenic Escherichia coli (EPEC) have acquired several virulence genes by horizontal transfer. These genes allow bacterial colonization of alternative niches and can consequently cause diseases. During the process of colonization, EPEC is exposed to various stressful conditions, such as low pH in the stomach and the presence of digestive enzymes. In this context, sigma S (RpoS) plays an important role in bacterial adaptation to this habitat. However, stress resistance has a price, bacteria that express high levels of RpoS are strongly resistant to environmental stresses, but display lower fitness due to a reduced ability to compete with other microorganisms under conditions of nutritional scarcity. Because of its antagonistic effects, different isolates of E. coli exhibit different levels of RpoS characterized by polymorphisms in the rpoS gene or in any of the several inputs that regulate rpoS expression. rpoS polymorphism and the intrinsic level of RpoS have profound implications on general bacterial metabolism, since the allocation of the RNA polymerase will be determined largely by these factors. It is therefore not surprising that RpoS also influences the expression of virulence genes. This proposal aims to investigate the role of RpoS in the mechanism of EPEC virulence.