PR002294 (Project)

Description:Bacteria of the Brucella genus are collectively responsible for brucellosis, a widely spread zoonosis. Our laboratory developed molecular tools to study growth and virulence of Brucella abortus at the single cell level. Using a genetic approach, we found that B. abortus selected a hybrid Mla-Pqi system (here called Mpc) anchored in the envelope, that is necessary to resist to envelope stress and to infect macrophages. We also found that the main component of the outer membrane, the lipopolysaccharide, is displaying a surprising traffic inside bacteria (the “round trip model”) that we propose to investigate. We also constructed a strain (here called RgsE*) that is growing bipolarly instead of unipolarly and we propose to analyze it to better understand polar ageing and potential polar virulence factors. One such polar virulence factor is the type 4 secretion system VirB, that we found associated to the new pole of the bacterium during macrophage infection. Altogether, our project aims to get a better understanding of envelope growth and properties, especially related to the virulence of B. abortus, with a high potential to generate new concepts that could be applicable to other bacterial pathogens.