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Biology PhD student successfully defends dissertation

On July 21st, Jennifer Greenwich of the Biology department successfully defended her dissertation in a public talk on biofilm formation in Bacillus subtilis, a bacterial pathogen that lives on plants.

Biofilms are bacterial communities that form on various surfaces, from medical tools to the human intestine. These communities are much more complex than just thin layers of cells. As part of a biofilm, bacteria exchange signals regarding their environment and form the extracellular matrix, a protein scaffold that helps them stay in one place. Microbiologists can obtain important information about biofilms simply by looking at them, as wrinkly architecture indicates robustness of the community.

During her time at Northeastern, Greenwich studied formation and architecture of biofilms and how they are affected by tyrosine kinases – enzymes that participate in phosphorylation of cellular proteins. Greenwich has also studied the role of an amino acid serine in biofilm formation. For this part of her research, she has developed a novel microbiological assay that measures levels of serine in the cell supernatant. Her work has resulted in a publication in Journal of Bacteriology, with another manuscript currently in preparation. Greenwich conducted her research in the laboratory of Dr. Yunrong Chai, where she was the first graduate student.

One piece of advice that Greenwich would give to current and future graduate students is to be aware of the “rough middle years” of the PhD program. For many students, third and fourth years are the time when the novelty of the program has worn off, but there still remains much work to be done for the dissertation. For Greenwich, a great way to achieve work-life balance was to volunteer for the National Park Service. During summers, she spent her Sundays working as a tour guide at the Longfellow House in Cambridge. Volunteering provided much-needed breaks from lab work, which in turn, says Greenwich, “made work in lab better.”

Now that her PhD work is done, Greenwich is planning to take some time to herself and travel around the U.S. before she begins her postdoctoral position in Indiana. As a postdoctoral researcher, she will also be studying biofilm formation. Her long-term career goals include securing a teaching position at a university, for which Greenwich has well prepared herself by working as a teaching assistant for the Anatomy and Physiology lab at Northeastern. As all attendees of her defense talk have certainly appreciated, Greenwich is an expert public speaker, who does a brilliant job conveying niche knowledge to a diverse audience.

Congratulations Dr. Jennifer Greenwich!

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