Variations in nutritional conditions promote metabolic adaptation of Salmonella within the host.

DIACOVICH L; LORENZI L; TOMASSETTI M; GARCÍA-VÉSCOVI E; MERESSE S; GRAMAJO H

Rosario

Congreso; Reunión Anual N° 50 de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2014

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Salmonella enterica serovar Typhimurium (S. typhimurium) is gram-negative pathogen that causes various host-specific diseases. During their life cycle, Salmonella must survive frequent exposures to a variety of environmental stresses, e.g. carbon-source (C) starvation. The virulence of this pathogen relies on its ability to establish a replicative niche, named Salmonella-containing vacuole (SCV), inside host cells. However, the microenvironment of the SCV and the bacteria and the metabolic pathways required during infection are largely undefined. The objective of this work is to develop different biological probes whose expression is modulated by the environment and the physiological state of the bacterium. We constructed transcriptional reporters by fusing promoter regions to the gfpmut3a gene, to monitor the expression profile of genes involved in the main metabolic pathways, focused in glucose utilization a lipid catabolism. The induction of these probes by a specific metabolic change was first tested in vitro, and then during different condition of infection in macrophages. We found sub-populations of bacteria expressing genes corresponding to differential pathway for utilization of source of C. These populations are altered in presence of different metabolizing substrate, suggesting the coexistence of Salmonella with diverse metabolic states during the infection.