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November 8, 2013
CONTACT: K.E. Schwab

Research examines fruit fly infection

SLIPPERY ROCK, Pa. - If you want to study neurodegenerative issues, you have to think small, which is just what Stacy Hrizo, Slippery Rock University assistant professor of biology and her student researchers are doing. Their research concentrates on fruit flies.

In a way, it's a big move up. Hrizo previously studied yeast - the one-celled fungi best known for making bread rise, and beer and wine ferment.

Her current research focus is examining neurodegeneration in fruit flies, where there is an uncontrolled loss of functional brain tissue. Potentially, this can be applied to understanding human neurodegenerative diseases.

"Down the road, there may be link between our research and understanding Alzheimer's, Parkinson's and Huntingdon's diseases in humans," she said.

The research, which is being conducted in Vincent Science Center labs, requires student researcher to use both biochemical and behavioral techniques to examine the development and potential treatment of neurodegeneration in fruit flies - formally known as Drosophila melanogaster. The study is particularly focused on examining the neurodegenerative disease called "TPI deficiency." Humans with this disease exhibit susceptibility to infections. Hrizo's research team is determining if flies with the same mutations as humans also exhibit infection susceptibility.

The current research team includes biology majors Rachel Hollingsworth from Independence, Ohio; Andrew Zelasco from Meadville; and Ethan Finver from East Stroudsburg.

Hollingsworth began working with her mentor as a freshman. "Dr. Hrizo approached me after I handed in my final for her class fall semester and asked if I'd like to get involved with her neurodegenerative research with fruit flies. I've been working with her ever since. The most interesting aspect of the project has been learning to effectively use the equipment within the Cell Biology Lab. I'm grateful to have the opportunity to work with the equipment, and feel a lot more confident in my ability to design and execute my own experiments," she said.

"It is rewarding to see what I have learned thus far in my academic career regarding the steps of the scientific method and how to execute an experiment. I also am interested to learn more about what effects media such as E. coli and Staph Aureus have on fruit fly neurodegeneration and mortality," she said.

Zelasco, who joined the project last summer, said, "I was very excited to get started working in the lab. This research project is very interesting, mainly because it is a brand new experience to be working in a lab and doing research."

"I also think that it is very interesting to be working with Drosophila - the fruit flies - which in modern-day medicine are known as 'model organisms.' It is very satisfying to know that any research done involving Drosophila could be very useful in helping to better peoples lives."

He said the best part of the project "is the people I work with. It is really a great experience, and a really enjoyable time. I enjoy the opportunity to apply what I have been learning in the classroom to our work in the lab."

"The research really involves a lot of counting," Hrizo said. "The students, working in teams, follow a group of fruit flies. They sterilize a tiny needle, then dip it into a specific bacteria culture, then inject the tiny fly's abdomen with the bacteria-covered needle before returning the fruit fly to its habitat. They then watch each batch of 50 flies for 72 hours, counting the number of flies that die, most probably from the injected bacterial infection."

The bacteria used in the testing are considered "mild," with no pathogenic bacteria involved, Hrizo said.

"Normal, unmutated flies should be able to able to fight off the bacteria. Normal flies, should not see death, but flies with infection susceptibility will die. We are comparing the amount of death in our normal flies and our TPI deficiency mutant flies," she said.

She said fruit flies are a near-perfect subject in the study because they grow quickly, you can get large colonies of flies, and they are easy to manipulate genetically. "Mice, while also good, can live three to four years, thus drawing out the experiment and slowing the results," she said.

"Research is like peeling an onion, each layer peeled back gives rise to new questions," she said.

Hrizo said her current research consists of a number of projects. "The latest project with the flies is looking at infection susceptibility - determining if TPI deficiency flies die when exposed to bacteria," she said. Other research projects involve examining fertility in the TPI deficiency flies and biochemical analysis of the metabolic activity of TPI deficiency model cells.

The current project started about 18 months ago and the SRU research team hopes to wrap up its work by December 2014 before having it published in a peer-reviewed journal.

"We are really building on one of our former undergraduate's research projects. Natasha Hardina, an August SRU health science graduate, started the original project and presented the preliminary results at the Genetics Society of America Annual Drosophila Research conference in Washington, D.C., last April," Hrizo said. The techniques being used in the lab are based on the 2011 Nobel Prize-winning work by Jules Hoffmann that established that the fruit fly's innate immune system was quite similar to that of humans, she said.

Students in Hrizo's classes also do hands-on experiments with the neurodegenerative fruit flies in lab. This provides students with hands on experience with hypothesis driven research in a classroom environment.

Hrizo, who joined the SRU faculty in 2009, earned her doctorate degree in molecular, cellular and developmental biology from the University of Pittsburgh. She has completed post-doctoral work and training at the University of Pittsburgh School of Medicine as well as its department of pharmacology and chemical biology and its program in neurodegenerative diseases.

She earned her bachelor of science degree at West Chester University.

Slippery Rock University is Pennsylvania's premier public residential university. Slippery Rock University provides students with a comprehensive learning experience that intentionally combines academic instruction with enhanced educational and learning opportunities that make a positive difference in their lives.