On the Track of the Next Antibiotic
Florida Southern’s Department of Biology was one of a select number of schools invited to participate in the Tiny Earth Network, a program that endeavors to discover new antibiotics needed to combat the growing problem of infections resistant to long-used antibiotics. FSC biology students cultivated bacteria from soil samples and noted which ones showed potential for producing compounds that would kill other bacteria.
A conversation between FSC Assistant Professor of Biology Brittany Gasper, who was overseeing the Tiny Earth Network research, and Assistant Professor of Chemistry Deborah Bromfield Lee prompted Dr. Lee to take the research to the next level. Why not try to isolate and identify the compounds that have antibacterial properties?
Dr. Lee is a specialist in organic chemistry, the branch that works on complex carbon-based compounds found in life forms, and she recruited students Lauren Harris and Suzanne Wilson to assist her in the research project. The task has not been simple or easy. The different compounds, known as metabolites, produced by the bacteria, first had to be purified.
“Purification takes a lot of effort and thought. Identification takes even more,” said Dr. Lee. “It’s like a jigsaw puzzle where the picture is fuzzy.”
Wilson, a junior biochemistry and molecular biology major, worked on the project last summer. She spent most of that time just figuring out what purification protocols to use. Finally the procedure produced small samples of pink-colored liquid suspension that still showed antibacterial activity. But what was it?
Wilson and Lee have faced several problems trying to identify the compound. First, the gas chromatograph used to analyze the liquid requires a minimum amount of the sample, and the purification procedures sometimes did not yield enough.
“We have to try different methods and instruments and figure it out as we go along,” Dr. Lee said.
Another problem is that the samples decompose, especially if exposed to light, as Wilson discovered to her chagrin.
“The compound is generally pink, but it turns red or orange after exposure. I left some samples out in the lab one day and the next they were all orange,” she said.
Wilson and Dr. Lee have not yet been able to identify the chemical structure of the compound. The project is still ongoing, but Dr. Lee thinks that the compound belongs to a class of metabolites known as prodigiosins, which have been used in antifungal, immunosuppressant, and antibacterial agents.
“It’s a very wide range of compounds. Our samples show the same response to ultraviolet light but with a different pattern,” she said.
For Wilson, it’s an opportunity to conduct research in her field of choice.
“I really wanted to do something related to biochemistry, and this has been a challenging project,” she said.