Students studied the effects of endocrine-disrupting compounds on frogs, led by Prof. Dan Choffnes.
SURE

'A long and complicated process'
with real-life implications

Students study effects of endocrine-disrupting compounds on frogs

Summer 2010

This summer, listeners to Illinois radio stations may have heard public service announcements urging them not to flush unused pharmaceuticals, but to dispose of the pharmaceuticals properly.

Among the pharmaceuticals are materials known as endocrine disrupting compounds (EDC), which, along with pesticides, personal care products, plasticizers, and both natural and synthetic estrogens, can get into local water systems. Four Carthage biology majors spent the summer studying the concentration of EDCs in the Pike River watershed, and the effects such chemicals can have on animals.

"I love this project, because it gives students many opportunities to learn a variety of scientific techniques, and because it has relevance to basic biology, the environment and medicine," said Dan Choffnes, assistant professor of biology, who was the research advisor for the students on this Summer Undergraduate Research Experience project.

Prof. Choffnes pointed out that EDCs "can be potent, and have an effect on wildlife at very low concentrations." As for potential effects on humans, "we don't know how well toxicology translates across species."

Explaining the background of the project, Prof. Choffnes said that "I'm a geneticist by training, and I'm interested in how cells in an organism respond to signals. All vertebrates have chemicals they use to signal within their bodies which are frequently involved in sexual identity, important developmental phases like puberty, or metamorphosis.

"In the past few decades, biologists have become aware that natural and man-made chemicals in the environment can interfere with normal signaling processes in animals."

The students gathered samples of water weekly at three locations along the Pike River: near the river's source in Racine County, adjacent to Case High School; on campus; and near the mouth of the river. They tested three substances: atrazine, a common herbicide; and two estrogens, a natural one produced in living organisms, and artificial estrogens found in oral contraceptives. "We're looking at concentrations in the Pike River to see if the concentrations are high enough to cause development problems," said Katie Gast, '11, from Muskego, Wis.

Students spent the vast majority of the 10-week project in a laboratory at Carthage, where they kept about 25 frogs in an aquarium tank they jokingly dubbed "The Dugger Family," after a cable television series about a family with 19 children. "There's no way we'll be able to name all of them in there," Katie said of the frogs. "We needed a name for a lot of kids."

Students sought to study how frogs were affected by various chemicals that they added to the water in which the frogs were raised. The chemical solutions were refreshed regularly.

"Testing for chemicals is a long and complicated process," Prof. Choffnes said. "We're looking for concentrations that might be in parts per trillion."

Anne Pioppo, '12, from Wheaton, Ill., explained the "calibration curve" used to measure how varied levels of chemicals affect the frogs. "After we create the standard solutions, doing several concentrations, we compare them to what we get in our river samples," she said. "We want to create a spectrum for comparisons."

Katie said the group usually met in the morning to "lay out our game plan." Stacy Kosinski, '12, who was one year behind Katie at Muskego High School, said the group divided tasks informally, aiming to give participants a variety of responsibilities. "We do most stuff together," Stacy said. "We all want to gain a lot of experience."

Scolastica Njoroge, '12, a student from Kenya, assisted the group part-time. She also worked at Hedberg Library, and has been shadowing a doctor at a Kenosha hospital. Frog tissues were sampled weekly, Scolastica said, adding, "you really can't see strong effects with the naked eye."

Katie said making links between cause and effect can take a decade or more.

"We want to create awareness," she said, "whether it's people disposing of medications differently, or farmers using different methods in their fields."

Prof. Choffnes agreed that research is a long-term proposition.

"The great thing about science is that we never have all the answers," he said, adding compliments to the budding researchers.

"They're a lot of fun to work with," he said. "The students have a lot of tenacity, a lot of energy, and a good amount of inquisitiveness. These are really good attributes for research scientists."

Scolastica hopes to attend medical school in the United States.

"This has been a very good opportunity for me," she said. "I have learned a lot through this experience."

Katie intends to go to dental school, and is applying for admission to at least five. She intends to pursue a doctorate in oral health, focusing on research and treatment of diseases, but ultimately hopes to practice pediatric dentistry. "This kind of gets your feet wet in what research is all about," she said.

Stacy is considering medical school or graduate study in medical research. "This is definitely giving real-life application to the lab work we do with our courses," she said.

Anne plans to study occupational therapy.

"I know this is going to help me get into graduate school," she said. "It will solidify that I'm passionate and dedicated to science."

Prof. Choffnes concluded that "the research they’re doing has a great number of human health implications. Graduate programs really like it when students have independent research experience."

— Bill Kurtz, Carthage College

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'A long and complicated process' with real-life implications
Students study effects of endocrine-disrupting compounds on frogs.