Melissa M. Kendall, PhD
Graduate School: Portland State University
Primary Appointment: Assistant Professor, Microbiology, Immunology, and Cancer Biology
Virulence gene expression in enterohemorrhagic E. coli O157:H7
Email Address: firstname.lastname@example.org
My research aims to understand how the human pathogen
enterohemorrhagic Escherichia coli O157:H7 (EHEC) integrates
environmental signals in order to colonize the host intestinal tract
and coordinate expression of virulence genes. EHEC is a normal resident
of cattle, but can cause disease in humans following the ingestion of
contaminated food or water. EHEC attaches intimately to intestinal
epithelial cells and triggers extensive cytoskeletal rearrangements
resulting in attaching and effacing (AE) lesions and formation of a
characteristic pedestal structure. Most of the genes involved in AE
lesion formation are encoded within a chromosomal pathogenicity island
called the locus of enterocyte effacement (LEE). The mortality
associated with EHEC infections is due to the production and release of
a Shiga toxin (Stx) by these bacteria. Stx is a potent inhibitor of
protein synthesis that binds to receptors found in the kidneys and the
central nervous system, thus causing the complications associated with
In order to successfully cause disease, EHEC must compete with the indigenous microbiota for nutrients. Ethanolamine (EA) is present in the large intestine due to the turnover of intestinal cells as well as through the host diet. EHEC uses EA as a nitrogen source and thus gains a competitive advantage for colonization over the indigenous microbiota. Recently, we have shown that EA is not only important for nitrogen metabolism, but that it is also used as a signaling molecule to activate genes involved in inter-kingdom signaling, AE lesion formation, and Stx production (Kendall et al., 2012).
Our laboratory is interested in trying to understand the regulatory cascade involved in ethanolamine metabolism and virulence gene expression in EHEC. Further understanding of this regulatory system will lead to the identification of novel virulence factors and may lead to the development of anti-virulence therapies.
M M. Kendall, C C. Gruber, C T. Parker, V Sperandio. Ethanolamine controls expression of genes encoding components involved in interkingdom signaling and virulence in enterohemorrhagic Escherichia coli O157:H7.mBio. 2012.
M M. Kendall, C C. Gruber, D A. Rasko, D T. Hughes, V Sperandio. Hfq virulence regulation in enterohemorrhagic Escherichia coli O157:H7 strain 86-24.Journal of bacteriology. 2011.
M M. Kendall, D A. Rasko, V Sperandio. The LysR-type regulator QseA regulates both characterized and putative virulence genes in enterohaemorrhagic Escherichia coli O157:H7.Molecular microbiology. 2010.
R C. Vazquez-Juarez, J A. Kuriakose, D A. Rasko, J M. Ritchie, M M. Kendall, T M. Slater, M Sinha, B A. Luxon, V L. Popov, M K. Waldor, V Sperandio, A G. Torres. CadA negatively regulates Escherichia coli O157:H7 adherence and intestinal colonization.Infection and immunity. 2008.
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