1. Survival of Legionella pneumophila in water. L. pneumophila is able to survive up to a year in water without the presence of any food source, i.e. susceptible protozoan. More information about L. pneumophila can be found here. We are using transcriptomic to uncover the mechanism underlying long-term survival in water, including the role of the stringent response and resistance to heat shock and chlorine. We are also interested by the effect of environmental conditions on the transmission potential of L. pneumophila to humans and on the induction of the viable but non-culturable state (VBNC).
Legionella pneumophila cells in water stained with the Live/Dead kit.
2. Microbial interactions in water systems. The growth of L. pneumophila in water systems depends on the presence of host cells, such as amoeba and ciliates. We are using microbial profiling tools to identify microbial interactions promoting and preventing L. pneumophila growth in water systems.
Microbial profiles of cooling towers.
3. Characterization of the small RNA expressed by L. pneumophila. Recent studies have identified 79 sRNAs expressed by L. pneumophila. Two of these sRNAs, called RsmY and RsmZ, functionally link three major response regulators of L. pneumophila virulence factors, the sigma factor RpoS, the RNA-binding protein CsrA and the two-component system LetA/S. Another identified sRNA is a homolog of the 6S RNA of E. coli, which affects the balance between different RNAP holoenzymes. It is an important regulator of L. pneumophila virulence since a 6S RNA deletion mutant is unable to compete against the wild-type during intracellular growth. There is currently no insight into the role of the other identified sRNAs. Therefore, the goal of this project is to identify phenotypes controlled by the sRNAs expressed by L. pneumophila and to identify the targets of the sRNAs associated with a phenotype.
4. Survival of Campylobacter jejuni in water. C. jejuni is a bacterium that naturally colonized the cecum of chicken and wild birds. Water contaminated with bird droppings is a source for the transmission of C. jejuni to human. C. jejuni is the most common cause of bacterial gastroenteritis in humans in Canada. We are investigating how C. jejuni survive in water and identifying which strains are better at surviving in water.
To view the 3 Minutes to Change the World audition videos about our research, click on the images below.