Steve Charette, Département de biochimie, de microbiologie et de bio-informatique
I am a full professor in the Département de biochimie, microbiologie et bio-informatique (Faculté des sciences et de genie) of Université Laval. I am affiliated with the Institut de biologie intégrative et des systèmes (IBIS) and the Centre de recherche universitaire en cardiologie et pneumologie de Québec (CRIUCPQ). I am a biochemist and a cellular biologist. My research has received funding from NSERC, FRQNT, CFI, and local foundations and organizations. I have developed a broad expertise on Dictyostelium discoideum amoeba and protozoa-bacteria interactions (see publication list below). More specifically, I am interested in host-pathogen interactions and in the identification of the virulence factors of pathogenic bacteria, especially Aeromonas salmonicida, by using D. discoideum amoeba as an alternative host model. In parallel, I am developing a research program on the role of protozoa in the protection and dispersal of pathogenic bacteria in the environment.
Pathogenesis is defined as the aptitude of a pathogen to trigger injury to a host organism. In the case of bacterial pathogens, different factors are expressed by the bacteria, which are essential for the implementation and the multiplication of the pathogen in its host. The identification of these virulence factors can be achieved if appropriate tools are used such as a suitable host model.
Dictyostelium discoideum amoeba is one of the most versatile alternative hosts to study bacterial virulence. Its behaviour, especially phagocytosis, is quite similar to that of macrophages and neutrophils of the immune system. D. discoideum is a haploid organism (one copy of each gene). This feature allows easy introduction of mutations in the genome of D. discoideum. Consequently, this amoeba permits a wide range of experimental setups for the analysis of host-pathogen interactions. This kind of approach is either difficult or impossible with other host models. Most importantly, D. discoideum can be infected by all human and animal pathogens tested so far. Moreover, amoebae are a known or suspected reservoir for many pathogens. Thus, the use of D. discoideum is appropriate for the study, at the molecular level, of the virulence of many bacterial species.