Biologist Uses Flies to Give NASA Space-Travel Insight

By Chris Bryant

NASA has awarded Dr. Janis O’Donnell, a UA professor of biological sciences, a three-year grant of more than $580,000 for research designed to provide more insight into the physiological effects of gravity changes.

O’Donnell’s research experiments are conducted on household fruit flies. No, NASA isn’t planning on the fruit flies, known in biological circles as Drosophilia melanogaster, piloting a future version of the Space Shuttle. Flies share with humans, and other mammals, some biochemical similarities, particularly in regard to chemicals produced within their brain cells during certain periods of change, said O’Donnell.

"NASA has an interest in what happens to organisms in long-term space flight," O’Donnell said.

Within the flies’ brain is a distinct type of neurotransmitter, dopamine, which is responsible for many hormonal functions and is created at increased levels when flies experience significant environmental change, O’Donnell said. It is believed that the regulation of catecholamines, of which dopamine is one type, is crucial to the flies’ ability to adjust to change, possibly including gravitational changes. If scientists can better understand the process, as it occurs in flies, it could shed light on ways to enable humans to better adjust to gravitational change.

Working with a collection of flies that have mutations in two specific genes enables the researchers to better understand how those genes function. O’Donnell suggests thinking of it in terms of an automobile. "I may not understand how a part works in a car, but if I remove that part I can see what happens to the car and gain a better understanding of how that part functioned."

While it’s not easy to reduce gravitational force in earth-based experiments, it is relatively easy to increase it, O’Donnell said. "We think, in all likelihood, the same nerve cells or the same molecules are involved whether gravitational force is increased or decreased." The researchers will map which cells respond to a specific environmental change.

By placing test tubes containing first the normal flies and later those with the mutated genes in a special centrifuge, a small machine that rapidly twirls the flies around in circles, O’Donnell and her student researchers measure the effects the increased gravitational pull has on the flies.

"Because it has a very simple nervous system, we can sometimes see if new nerve cells are expressing the genes we study or if there are changes in expression," O’Donnell said. The UA researchers measure the effects with both high-tech, and more traditional, observation means. By placing the flies’ brains under a special microscope, called a laser confocal microscope, researchers can see first-hand some of the genetic changes that have occurred following the flies’ exposure to increased gravitational force. The researchers also use stop watches to measure how long it takes the flies to climb up a specific distance within the test tube after having gone for a spin.

By comparing and contrasting the mutated flies to the typical flies, the researchers hope to learn more about how these genes function.

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