Marshall, Natalie

Faculty of Science
Doctor of Philosophy
B. Brett Finlay
Toronto, Canada
Vanier Scholarship
Examining the effects of secreted bacterial proteins on human cellular processes, including proteolysis, and their contribution to virulence
The foodborne pathogen enterohemorrhagic Escherichia coli (EHEC) causes severe diarrheal disease and significant mortality worldwide. In Canada, EHEC causes an estimated 50,000 infections per year and numerous deaths. Outbreaks from EHEC-contaminated water (Walkerton), beef (XL Foods), and cheese (gouda) further highlight the relevance of this pathogen to Canadian health and industry. My research aims to understand how human cellular functions are disrupted by EHEC infection, specifically by EHEC proteins that are injected into human cells by the syringe-like type III secretion system. Using a proteomics technique developed at UBC ("TAILS"), I study how injected EHEC proteins affect pathways, proteins, and global proteolysis in human intestinal cells during infection. This research will advance our understanding of the effects of these injected proteins on the infected human cell and the molecular mechanisms by which these proteins contribute to human disease. This study could also reveal clinical targets against EHEC.
Over the course of my PhD studies, I hope to further characterize the mechanisms by which this pathogen causes human disease. Specifically, I would like to identify novel mechanisms by which EHEC proteins subvert host cell defenses or manipulate host cell pathways to cause disease. Ideally, I hope to identify a therapeutic target to alleviate the burden of this disease.
Receiving the Vanier scholarship is an honour. This award affirms the value of experiences both in and outside the lab, notably academic, leadership, and research experiences. I am therefore very grateful to those who have supported me in these experiences, especially my academic and research mentors at the University of Guelph, my research mentors elsewhere, and my current research team at UBC. Lastly, I thank the Vanier-Banting Secretariat and CIHR for this contribution to my studies.
Vancouver is an active city; there are many opportunities on- and off-campus to try new things: rock climbing, SCUBA diving, skiing - you name it. On campus, there are many ways to get involved and meet people. In my experience on campus, I've enjoyed the ongoing collaboration and communication between students, the student societies, and the University. Similarly, I find researchers on campus to be very open to collaborations, creating a healthy and supportive research environment.
I came to UBC to pursue my current research topic. After learning about bacterial type III secretion systems - the topic of my current research - from a professor at my alma mater, I was fascinated and wanted to pursue this topic in my graduate research. Dr. Finlay's lab at UBC has conducted high-impact research on the type III secretion system and host-pathogen interactions. Furthermore, UBC is known across Canada as a leading research university for the life sciences and has a phenomenal reputation in microbiology.

Throughout my undergraduate degree and the co-op program, I enjoyed every opportunity to be involved in research, including several research opportunities in academia. I am pursuing a PhD in order to continue independent research, having enjoyed my previous research experiences so thoroughly. After completing this program, I hope that my experience and qualifications will enable me to continue with further independent research projects outside of graduate school.