Although Cryptococcus neoformans can make people sick, to Felicia Walton the fungus is also a work of art when captured microscopically. In one image, the cell walls of a malformed strain of the fungus glow bright blue when stained with a dye called calcoflour white, and its cellular nuclei shine emerald when stained with a dye called sytox green.
"Looking at something as stunning as that and being able to gain some kind of insight from it is one of the reasons I'm studying biology—the visual aspect," says Walton, a Trinity College senior.
The editors of the research journal Molecular Biology of the Cell were impressed, placing Walton's fungal portrait on the cover of their September issue. Walton also was first author of a report in the same issue on these and other oddly elongated Cryptococcus cells. Her co-authors were Alexander Idnurm, a research associate in Duke's department of molecular genetics and microbiology, and Joseph Heitman, director of the Duke Center for Microbial Pathogenesis and head of the lab in which Walton works.
To do the work described in her latest journal article (she co-published an earlier paper with Idnurm and Heitman), Walton created a genetic library of about 50,000 abnormal forms of Cryptococcus and then looked for strains whose cells could no longer properly divide. Her paper zeroed in on six genes and associated proteins that caused the normally round cells to form stretched-out shapes. That information could help researchers develop ways to disable the fungus, which can cause life-threatening infections in the nervous systems of patients with compromised immune systems.
In earlier work, Walton investigated how Cryptococcus produced protective coatings of the pigment melanin to help maintain its pathogenic potency. Then she cultured thousands of different strains of the fungus on laboratory petri dishes, looking for mutant forms—and their associated genes—that could no longer properly make melanin.
"At the time, the whole field of Cryptococcus research knew of only two or three genes involved in that process," Idnurm says. "Felicia managed to find another six genes. It was an incredible achievement—like doubling the current research knowledge."
Growing up in Asheville, North Carolina, Walton discovered an early interest in science. She had parents "who convinced me that I could do whatever I set my mind to," she says.
Walton entered Duke's signature FOCUS Program, which provides first-year students with opportunities to attend interdisciplinary seminars with leading researchers clustered around a common theme—in Walton's case, biotechnology. She contacted Heitman to gauge his willingness to let undergraduates conduct research in his lab. "When I first approached him, I just wanted to get my foot in the door," she says. "[Heitman] told me that I was going to start doing real research, right away, just headfirst."
"Felicia has matured into a full-fledged contributing member of our research group," Heitman says. "This is no small task for an undergraduate working in a group of a dozen postdocs and four or five graduate students. Even among this talented group, Felicia stands out with her ability, her questions, and her productivity."
Walton, a double major in biology and chemistry, has received a prestigious Marshall Scholarship, which she plans to use to earn her master's degree at the University of Cambridge, and she may continue on there to work on a Ph.D. "I'm going to be studying cell division in mammalian cells, which is somewhat related to what I've been doing at Duke," she says. "Cambridge has an outstanding history of scientific contribution that I'm excited about. And the other big draw for me is the opportunity to live and work abroad for several years and meet new people and experience new cultures."
Felicia Walton, the aesthetics of biology
January 31, 2007