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 Carolina Tropini

Talk Title:
How the environment shapes the microbiota in health and disease

Wednesday, January 20th, 2021 @ 11:00am ~ 12:30 pm (Pacific Time)

Virtually on Zoom at:

Assistant Professor, Department of Microbiology and Immunology/School of Biomedical Engineering, UBC

The Tropini lab is investigating how a disrupted physical environment due to altered nutrition or concurrent with intestinal diseases affects the microbiota and host at a multi-scale level. They are a cross-disciplinary group that incorporates techniques from microbiology, bioengineering and biophysics to create highly parallel assays and study how bacteria and microbial communities function, with the goal of translating the knowledge gained to improve human health.

Dr. Tropini conducted her Ph.D. in Biophysics at Stanford University. Her studies in the laboratory of Dr. KC Huang combined computational and experimental techniques to investigate bacterial mechanics and morphogenesis. In 2014 she received the James S. McDonnell Foundation Postdoctoral Fellowship Award and she joined the laboratory of Dr. Justin Sonnenburg at Stanford. During her post-doc, Dr. Tropini applied her background in biophysics to study the impact of physical perturbations on host-associated microbial communities living in the gut.

Cataloging membership of the gut microbiota has become routine via high-throughput -omics techniques; however, understanding the functionality of individual members in the context of their habitat remains challenging. Characterization of stool samples–a mainstay of microbiota studies–provides a snapshot of the gastrointestinal system that may not be representative of what is occurring within the host, and is unable to capture the variation in bacterial localization and function along the length of the digestive tract. Understanding interactions between bacteria and their environment is greatly enhanced by techniques that preserve bacteria in their context, like quantitative imaging. In this talk, I will discuss the principles governing the localization of intestinal bacteria and spatial relationships between bacteria and their hosts. I will focus on the impact of osmotic perturbation to the gut ecosystem, a common disturbance caused by food intolerance, malabsorption, and widespread laxative use. We have assessed the resilience of the gut ecosystem to osmotic perturbation at multiple length and time scales. By sequencing, we have shown that osmotic stress causes consistent, lasting changes to human and mouse microbiotas in a mouse model, leading to the extinction of highly abundant taxa and expansion of less prevalent members. Importantly, quantitative imaging has enabled us to identify how changes in the gut environment lead to disruption of the native microbiota membership and function. We show that the mucosal interface separating bacteria from the epithelium is decimated during osmotic perturbation, leading to decreases in mucin consuming bacteria and mucin glycoside hydrolase expression by commensals. Lastly, I will discuss future directions and challenges for biogeography studies of the gut microbiota.
Introductory Speaker:
cameron Herberts (UBC, Alex Wyatt lab) Cancelled

Talk Title:
Deep whole-genome sequencing of prostate cancer circulating-tumour DNA