Katie Guzzetta ’18 in the lab with mice.

Katie Guzzetta ’18 first learned about the gut microbiome while she was in middle school,  and has been intrigued ever since. The human microbiome consists of the microbial community harbored by each person, composed primarily of bacteria in the gut. Since the term was coined by Joshua Lederberg in 2001, microbiome projects have been launched worldwide in order to better understand the important role these bacteria play in impacting human health and well-being.

During her freshman year, Guzzetta received funding from Hamilton to begin her own microbiome study with lemurs in Madagascar. This summer, however, her research is closer to home, with mice at Hamilton College. “As far as depression goes, I’ve had many friends who’ve been directly affected by the mental illness, which is far too common among college students. Since binge drinking and depression are both prevalent on college campus, and both have links to the bacteria in our guts, the microbiome is naturally a novel and possibly important channel of connecting these,” said Guzzetta.

Twice a week, Guzzetta feeds some mice a binge amount of mealworms injected with a diluted ethanol and water mixture. A few blood alcohol content tests at the beginning and end of this project using a headspace GC/MS instrument will allow Guzzetta to ensure the mice are hitting the legal binge blood-alcohol content of 0.08%. This work has passed ethics review.

She then collects rodent fecal samples from which she is able to analyze gut microbiome composition. “The microbiome is directly impacted by the food you eat. By analyzing these samples, I am trying to determine the bacterial effect of binge drinking,” said Guzzetta. In addition, she also conducts behavioral tests, which allow for documentation of observable changes in behavior throughout the study, and can be coupled with microbiome data to confirm depressed behavior.                                                                                      

about Katie Guzzetta ’18

Major: Biochemistry/Molecular Biology

Hometown: Pittsford, N.Y.

High School: Pittsford Sutherland

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After a comprehensive mapping of the mice’s internal bacteria, Guzzetta will compare her samples to those from past studies on bacterial compositions of gut microbiomes in patients with and without depression. “Best case scenario, I will have conclusive evidence that binge drinking alters the gut microbiome significantly in ways that may correlate to depression,” she said.

Guzzetta will continue working with the mouse gut microbiome for her thesis, and will utilize the work started by Emma Anderson ’17, who began a study on the impacts of the western diet on the gut microbial community last year for her thesis. Guzzetta hopes to compare her results, as well as data from samples that have yet to be analyzed, to possibly find a link between the western diet and gut microbial compositions that may correlate with depression or other mental illnesses, or a project similar. 

Assistant Professor of Biology Cynthia Downs continues to mentor both students who were supported with Downs’ research funds and are members of her research lab.

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