The Origins, Evolution, and Consequences of Bacteria-Animal Interactions

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H-NS (red) binding to DNA (gray).  (Structure solved by our collaborators in the lab of Dr. Bin Xia, Peking U).

Research in the Navarre lab is aimed at understanding how and why bacteria evolved to cause disease in animals (including humans).  We are also initiating studies on the microbes normally associated with animals and how they affect health.

Evolution of bacterial pathogensThe lab has made major contributions to our understanding of how bacteria become pathogens by picking up DNA from other bacteria, a process known as lateral gene transfer (LGT).  Specifically we focus on bacterial proteins, like H-NS in E. coli and Salmonella or Lsr2 in Mycobacteria, that control genes acquired by LGT.  As a result of their activity, these proteins are the master regulators of toxin expression in pathogens that cause tuberculosis, bubonic plague, cholera, typhoid fever, and dysentery.  

Human cell infected with Salmonella (red).  Membrane structures inside the human cell that are caused by Salmonella infection are stained green and the nucleus is stained blue.  
(image by Betty Zou)

Bacterial metabolism and virulenceIn collaboration with labs in the Department of Immunology we are also inititating several projects to explore the role bacterial-derived metabolites play in colorectal cancer (CRC).  Our recently published study in Cell provides compelling evidence that a subset of colorectal cancers are driven by the metabolites provided by gut bacteria. 

We have also defined a novel mechanism of regulation that is critical for bacterial virulence and stress resistance that involves the post-translational modification of a poorly understood ribosome-associated elongation factor (EF-P). Salmonella strains lacking EF-P are unable to cause disease in mice and also display a variety of metabolic defects.  We are exploring the contribution bacterial metabolism makes to virulence, in particular how bacteria adjust their metabolism when under attack by the host-immune system in order to promote their survival and growth.  


ANNOUNCEMENT:  NEW ONLINE MICROBIOLOGY COURSE STARTING IN JANUARY 2015.  STUDENTS NOT FROM THE UNIVERSITY OF TORONTO SHOULD VISIT: www.onlinemicrobiologycourse.com


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Navarre lab - university of Toronto