Bacterial Pathogenesis

Members of the Faucher lab have a focused interest on the behavior of bacterial pathogens in non-clinical environments, such as in water. Survival and perhaps growth of water-borne pathogen in this environment is crucial for its transmission to its host. What are the genetic factors and environmental factors that influence its behavior in the non-clinical environment and its further transmission to the host are among the top questions that are shaping our research.
We use transcriptomic tools extensively to answer these questions, and the data generated from these studies are used to identify new systems involved in the non-clinical environment and in host-pathogen interactions. We are fully equipped to perform high-density microarray experiments.

L. pneumophila microarray.
Our primary model organism is Legionella pneumophila, a Gram-negative pathogen that can be found in almost any natural or human-made water system. L. pneumophila is able to replicate inside a wide diversity of phagocytic protozoans found in water. It is the causative agent of Legionnaires' disease, an acute form of pneumonia. After inhalation of contaminated water droplets, Legionella infect and replicate inside alveolar macrophages. This phenotype is completely dependent on a Type IVb secretion system that translocates ~200 effectors into the host cells. These effectors modify the normal phagocytic pathway to the benefit of Legionella. Many regulators are known to play a role in the expression of virulence factors, such as two-component systems and small regulatory RNAs (sRNA). 

 Mechanism of regulation by sRNAs: riboswitch (A), cis-encoded base-pairing sRNA (B), trans-encoded base-pairing sRNA (C), CsrA-CsrB system (D) and the 6S RNA-RNA polymerase system (E). sRNA are colored blue, the mRNA targets are colored in red.

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There is no sin in being ignorant; the sin is to remain ignorant.
Roy Curtiss III

In the fields of observation, chance favors only the prepared mind.
Louis Pasteur

I believe in evidence. I believe in observation, measurement, and reasoning, confirmed by independent observers. I'll believe anything, no matter how wild and ridiculous, if there is evidence for it. The wilder and more ridiculous something is, however, the firmer and more solid the evidence will have to be.
Isaac Asimov


Sebastien P. Faucher
Associate Professor
Department of Natural Resource Sciences
McGill University
21,111 Lakeshore Rd.
Ste. Anne de Bellevue, QC
H9X 3V9
Tel: 514-398-7886

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