A Laser Focus

Brandeis Stories

A Laser Focus

Probing genetic mysteries as an undergraduate researcher

By David Levin
July 18, 2024 • Research

In a warm, dimly lit room in Brandeis' biochemistry department, Fiona Stewart '25, is about to begin her next experiment. She dons a pair of tinted goggles, leans over a metal table filled with an array of lenses and mirrors, and casually fires up a high-powered laser.

Stewart is an undergraduate researcher working in the lab of Jeff Gelles, Aron and Imre Tauber Professor of Biochemistry and Molecular Pharmacology, where she studies how E. coli bacteria survive periods of intense stress. It sounds like advanced work - and it is - but Stewart isn't vying for an advanced degree. For the past three years, she's been a fellow in Brandeis' Quantitative Biology Research Community (QBReC), a program that lets undergraduates dive into real-world scientific research as soon as they arrive on campus.

Today, as a rising senior, Stewart is chipping away at some profound questions about the genetic machinery inside E. coli. Under normal circumstances, she said, the bacteria happily cruise along, making proteins that let them thrive and multiply with abandon - but when the cells encounter extreme stress, like a lack of food or overcrowded conditions, they start to express a totally different set of genes that tell them to stop growing, slow their metabolism, and enter a hibernation-like state to preserve energy. Stewart wants to understand why and how this change takes place.

"It's sort of like if you were at a banquet with 20 people, and you were having a feast, and then somebody told you that you were going to be locked in the room for two weeks, so you've got to preserve everything you have and ration it out," she said. "That's the kind of shift in activity that the E. coli needs to make."

Exactly what triggers this sudden shift isn't clear, but when it occurs a molecule called Rsd seems to double in concentration within the cell. Stewart is trying to uncover the role that Rsd plays in the bacteria's metabolism, and is studying how the protein may help E. coli survive adverse conditions (that's where the lasers come in: using specialized laser-fluorescent dyes, she can make Rsd glow green as it binds to other molecules, offering a vivid window into its activity).

Although the work is in its early stages, she said, the process of learning and discovery has been exhilarating - especially when it has led her in unexpected directions.

"When you focus in on one small area of science, you get exposed to a whole treasure trove of information, and you never know what you're going to find that excites you," she said. "One great example is data analysis. I didn't think I'd be very interested in that at the start, but now it's one of my favorite things to do. That's why I definitely recommend getting involved in undergraduate research while you're at Brandeis - it's such a unique opportunity to learn and grow."