On Friday, May 17, Tim Jegla will receive a doctorate in neuroscience and, apart from his own hard work and initiative, he owes his success to his biology professor parents; to his adviser, Lawrence Salkoff, Ph.D., professor of anatomy and neurobiology at the School of Medicine; and to the long, cold winters of Minnesota.
Tiring of the winters after two years of undergraduate study at Carleton College in Northfield, Minn., Jegla applied for and received a National Science Foundation Research Experiences for Undergraduates (REU) Fellowship that took him to the University of Florida's Whitney Marine Laboratory in quaint, venerable St. Augustine. There, he became exposed to the neurobiology of jellyfish, one of the oldest, most primitive animal species on Earth.
The work excited him, sparking an interest in the evolution of the nervous system across species, and the mild Florida environment provided ample opportunity to pursue two of his avid interests, running and bird-watching.
"The hands-on experience of working with a neurobiologist really showed me how fascinating this area of biology is," Jegla said. "I grew up in an environment saturated with biology, but I would not have thought about making a career out of this area were it not for the fellowship."
The research experience led him indirectly to Salkoff and Washington University. In his senior year at Carleton, Jegla wrote an extensive research paper, partially based on his REU experiences, on the evolution of ion channels. In the human brain, ion channels act as transistors, relaying electrical pulses across neurons, eventually resulting in a chemical signal that directs a muscular response -- for instance, a contraction.
Researching his paper, Jegla learned that all mammals and fruit flies have the exact same set of these channels, that there were four families of genes that code for voltage-gated (responding to electrical stimuli) potassium channels, key players in the process. He also realized that Salkoff's name kept appearing on many of the landmark papers he read and referenced for his project.
When he visited Washington University to consider graduate school, Jegla was weighing the merits of plant biology as well as neurobiology.
Then he met Salkoff.
"Larry said that I could work with him and find out some of the answers to the questions I posed in the paper," Jegla recalled. "I thought that was a very good idea. The neuroscience program here provided me lots of opportunity to shift about so I could find out exactly what I wanted to do."
From the fall of 1990 until now, Jegla has immersed himself in physiology, genetics and molecular biology, learning gene-cloning techniques and assays in Salkoff's laboratory. He satisfied his curiosity about the evolution of the nervous system by studying jellyfish, one of the most primitive animals to have nervous systems, and protozoan paramecium. He focused on the molecules underlying the "action potential," which carries electrical signals across excitable cells. The action potential "wave" is a chain of events involving the opening of sodium, calcium and potassium ion channels.
Eventually, he cloned a unique, previously unknown family of potassium channels in paramecium that are distinct from those present in higher animals. He also was able to show that the set of genes encoding ion channels in jellyfish is virtually identical to the set expressed in the human brain. Jegla measured the electrical signals from the jellyfish channels with a voltage clamp, which also allowed him to compare the structure and function of these ion channels across species.
"Tim has shown that the electrical properties of the human brain have their origins in mechanisms that were already present in the first animals on Earth," Salkoff said. "He's been an outstanding graduate student with a very significant record of accomplishment in neurobiology."
While his work helps explain the evolution of the nervous system, Jegla's inroads also may have implications for understanding brain diseases.
Jegla's parents are biology professors at Kenyon College in Gambier, Ohio. They imparted to him a strong interest in ecology and an abiding pastime: bird-watching.
Jegla and his wife, Adrienne, a graphic artist, have listed 500 birds they've observed in North America. They take pictures of some of the more striking birds and, in recent years, have fashioned calendars from their sightings that they give as Christmas presents to family and friends.
An outstanding distance runner in high school and college, Jegla runs as many as 40 to 60 miles a week when he prepares for an amateur road race, and he's placed quite high in several St. Louis-area races. A goal is to run a five-kilometer (or three-mile) race in less than 15 minutes.
The Jeglas will hit the turf and wildlife areas of northern California when he starts a three-year postdoctoral fellowship at Stanford University this summer. He will be working with Stanford biologist Richard Aldrich, Ph.D., in part to correlate what he has learned about potassium channel evolution with potassium channel function.
"I'll be concentrating on structure and function, as well as learning some new biophysics techniques," Jegla said. "Combined with the knowledge I've gotten at Washington University and what I'll learn at Stanford, when I'm through there, I should be ready to research on my own."
-- Tony Fitzpatrick
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