This month, as most researchers gear up to teach, two scientists are heading into the classroom to learn. Geoff Brumfiel asks why a physicist would want to enrol in biology lessons.
This spring, David Hartley found himself leading a double life. By day, he was teaching a class at the University of Maryland School of Medicine in Baltimore. By night, he was a student at George Washington University in Washington DC.
Hartley, a surface physicist by training, is one of a small but growing number of professional physical scientists who are going back to university to begin new careers in biology. Under a unique grant programme from the National Institutes of Health (NIH), about 20 mid-career scientists each year are going back into the classroom. The grants, known as K25s, allow researchers to spend up to five years learning the discipline of their choice.
“Physics has always been the centre of my world, ever since I can remember,” Hartley says. But by next spring, he will have completed a master's degree in public health and will begin an active research programme that will combine his knowledge of maths with his new-found love for epidemiology.
Even second time round, university can be daunting. At 37, Hartley has found juggling the roles of student and researcher particularly testing. “It has been very taxing in the past year, trying to do research, teach, do coursework and maintain a life with my family,” he says.
His new student life has required a shift in thinking as much as a shift in routine. Trying to grasp the breadth of a field such as epidemiology is tricky, Hartley concedes. “You have sociologists, statisticians, epidemiologists and microbiologists all working in public health — and they don't necessarily speak the same language,” he says. “The most challenging thing for me is getting my arms around all of this.”
Since the K25 programme began in 2000, the NIH has given out more than 120 grants to chemists, engineers, physicists and mathematicians, all of whom are looking to transfer their skills to biological research. From the agency's perspective the potential benefit is huge. Key developments in the biological sciences, such as protein crystallography, electron microscopy and magnetic resonance imaging, were all pioneered by physicists. And increasingly, biomedical science is being advanced by broad, interdisciplinary teams of diverse scientists, according to Norka Ruiz Bravo, the NIH's deputy director of extramural research.
Hartley, who had spent years in private industry doing defence-related research, saw the K25 grant as a route back into academia. But for a scientist with the security of a faculty position, what is the motivation to switch fields in mid-career? For David Beebe, another K25 participant, it was a combination of professional interest and personal experience.
After training as an electrical engineer, Beebe had become, at 41, a successful researcher in microfluidics, the flow of fluids through tiny channels. His 25-person lab at the University of Wisconsin at Madison was churning out about a dozen papers a year, and he was considered a leader in the field.
Among other projects, Beebe began to experiment with ways that microfluidic channels might be used to automate certain aspects of the in vitro fertilization process. “We started doing some experiments and saw that, lo and behold, the embryos were developing almost as quickly as they were in vivo, but we didn't know why,” he says. “I realized I needed to know more biology.”
Around the same time, Beebe says, he found himself becoming more personally drawn to biology. A friend had developed breast cancer, and that got him thinking about how his research might be able to contribute to advances in medicine. “I really wanted to make a contribution to humankind, as silly as that sounds,” he says.
So Beebe decided to go back to school and study cancer biology. Originally he wanted to apply for a full PhD programme, but he was dissuaded by colleagues. “Most of the people here said, ‘You're crazy, why do you want to get another PhD?’,” he explains. Ultimately, he chose to focus on classes that interested him rather than trying to earn another degree.
My first reaction was, oh God, these guys are so immature, but then I stopped and thought, no, I was just like that. David Beebe
Once back in school, Beebe faced a culture shock. In his first year, he found himself in an undergraduate-level organic chemistry course, and was horrified to discover that many of his 300 classmates were more interested in discussing parties, sports, boys, and anything other than the organic molecules they were there to study. “My first reaction was, oh God, these guys are so immature,” he says, “but then I stopped and thought, no, I was just like that.” Beebe says that the experience has reminded him “where his students' heads are at” when they come to his classes.
These experiences have also helped him to relate better to the students in his lab, according to Jaisree Moorthy, a postdoc and former graduate student of Beebe's. This is despite worries that the K25 programme would be disastrous for the lab. “I had 20 graduate students, and only found out I got the grant a few months ahead,” Beebe recalls. “So ramping down has really been the biggest struggle.” But the programme has actually made Beebe more available to his students: “Since Dr Beebe has gone back to school, he is more accessible as he does not travel as much,” says Moorthy.
Despite their overwhelming schedules, colleagues say that both researchers are already making significant contributions to their adopted fields. “David Hartley really asks some interesting research questions,” says Eli Perencevich, an epidemiologist at the University of Maryland. Last year, colleagues asked Hartley, Perencevich and others to study an outbreak of methicillin-resistant Staphylococcus aureus that had occurred in the university hospital's ward for prisoners. “David started thinking about what a person who wanted to control an infection would need to know,” Perencevich says. “And he was able to take a very complex model and break it down into three or four parameters that infectious-health professionals could use to control it.”
Beebe's studies could have payoffs in the field of stem-cell research, according to his mentor Caroline Alexander, a geneticist at the University of Wisconsin. Alexander and Beebe have been collaborating on a mouse model of how breast cancer tumours develop. They believe that the origin of the tumours may be linked to stem cells in the mouse's breast. “It's become very interesting from a therapeutic point of view to understand the biology of these stem cells,” she says. Researchers have long wanted to study how proteins secreted by these cells regulate their development. But this is almost impossible to do in a normal Petri dish because it contains millions of cells all signalling to each other at once, Alexander says. By contrast, the narrow channels in Beebe's microfluidic device hold far fewer cells, and their environment is easier to control. By switching the fluid flow through the channel on and off, the researchers can modify the signalling activity. “This is a great environment to test out how cells are regulating one another,” Alexander says.
The road ahead
When Hartley finishes his courses next spring, his research will kick into high gear. Rather than a thesis, the second half of the K25 programme requires him to produce publishable research findings. Hartley plans to develop a mathematical model linking cholera outbreaks to environmental, social and climatic factors. Beebe says that after his courses end next autumn, he hopes to begin asking his own research questions, rather than following the cues from his collaborators. “Next fall, I'll take complete ownership of my research,” he says. “To me, that's going to be the big transition.”
For us to make progress, we've got to recognize the importance of people from alien disciplines. Glen Morris
For Ruiz Bravo, it's these research projects that make the K25 programme so valuable. “Life science has moved from involving a single investigator in his or her lab to dealing with bigger types of problems that require large teams,” she explains. Although the NIH is also actively training graduate students in multidisciplinary fields, there are some distinct advantages to recruiting mid-career researchers. “These researchers are already very well trained in their particular area,” she says. “They bring a different approach to the life sciences.”
That approach is centre stage at the University of Maryland, where Hartley is giving what seems to be an introductory physics lecture. The differential equation on his overhead screen — familiar to any physicist — describes how a gas will diffuse through a room, but Hartley is using it to model how Chytridiomycota, a waterborne fungus that causes disease in amphibians, spreads in a population of frogs. His students, mostly epidemiologists, look forlornly at the mathematics overhead, and Hartley is sympathetic. He knows what it's like to be in their shoes: after class ends he will drive 100 kilometres south to attend a three-hour lecture in biostatistics. For now he smiles at his bewildered audience: “You guys wanted to learn more about this physics stuff,” he reminds them.
Hartley's students may take more convincing, but his new colleagues are enthusiastic about his changing career. Glenn Morris, who chairs the department of epidemiology and preventive medicine at the University of Maryland School of Medicine, says that he fought hard to bring Hartley to his department. “The physics guys are way ahead of us when it comes to modelling,” he says. “For us to make progress, we've got to recognize the importance of these people from alien disciplines.”
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Brumfiel, G. Back to school. Nature 437, 470–471 (2005). https://doi.org/10.1038/437470a