||Students study the effects of alcohol on embryos
RELEASED: November 26, 2009
By Leigh Ivey
DANVILLE, KY—For the most recent lab assignment in his developmental biology course, assistant professor of biology Dr. Brian Storz took an uncommon approach.
Rather than asking students to simply examine slides of embryos and make observations about growth and development, he allowed his upper-level biology students to investigate firsthand the effects of fetal alcohol syndrome (FAS) on developing chick embryos.
"Basically, we're quantifying the effects of FAS on the embryos, the implications of which are directly related to human health," says Megan Gatewood '10 of Louisville. "We're measuring things like size of the eyes and heart rate. It's commonly known that birth defects are associated with FAS, but this experiment will show directly what developmental processes are affected."
On the first day of the experiment, the students explanted nine chick embryos from their eggs. They then added one milliliter of 0.1 percent alcohol to three embryos, a milliliter of one percent alcohol to three others, and no alcohol to the last three, which served as controls.
Each day afterward, the students returned to the lab for observation and data collection.
Developed by Peter Armstrong at UC Davis, the experiment is one in which Storz himself participated as an undergraduate.
"It was definitely one of the labs that resonated with me for the rest of my life," he says. "It's one thing to look at images in a book and on slides, but to really be in touch with developmental biology, there's nothing like maintaining a living embryo through development—coming in every single day, checking on it, watching it grow and develop all its features, and seeing how similar it is to pictures of human embryos that students see every day in books."
Like most of the students taking part in the experiment, junior Ben Cocanougher of Springfield, Ky., enjoyed the interactive components of the three-week experiment.
"In Dr. Storz's labs, you don't just look at slides all day," he says. "He does a great job tying in the class lectures with real-life experiments, so this lab has had a much bigger impact on my memory than some. We're able to really understand now how embryonic development takes place."
And because Storz asked each pair of students to choose a different aspect of development to observe, the students were able to make numerous discoveries.
The 16 students taking part in the developmental biology course were juniors and seniors who have the biology background, Storz says, that enabled him to tell them, "Go do science."
Louisville native Amanda Stovall '11 explains Storz's techniques for leading lab projects.
"We're given the tools to work with, then we choose what to study and design our own methods," she says. "This allows us to work in areas of our own interests, and it's made me personally feel very involved in the research."
Jeff SoRelle '10 of Waco, Texas, agrees that the hands-on approach made this lab experiement exceptionally rewarding.
"The coolest part of this lab was how Dr. Storz empowered us to design our own experiment," he says. "Sometimes other labs can be 'cookbookish' because everyone just follows along doing the same things, knowing what the results will probably be. But here, we were doing an experiment without knowing what the outcomes would be. And this is the essence of science—looking at something interesting without knowing what will happen."
When the class began the experiment, the chick embryos were three-and-a-half days old. Seventeen days later, the lab project came to an end—and the students, who saw clear qualitative changes in the embryos they observed, had an enormous amount of data to analyze and present.
Stovall made a particularly interesting observation—and one that is important for research concerning fetal alcohol syndrome in humans—about the effects of alcohol on the vascularization of the extra-embryonic tissues.
"This is synonymous with mammalian placenta in that it’s how the embryos receive nutrients for growth," she explains. "In general, ethanol decreased the vascularization—less blood vessels, which also proved to be more fragile—which restricted the amount of nutrients the embryo could pull from the yolk sac."
This, she notes, would ultimately hinder the chick's ability to develop properly.
"Although we used two different treatments of differing concentrations of ethanol, this data supports the hypothesis that the timing of exposure to ethanol proved to affect the vascularization more so than the amount."
This discovery relates to that made by another group, who found that there is a marked difference in the size of the embryo based on alcohol exposure; those exposed to the ethanol resulted in smaller embryo size.
"This correlates perfectly with human observations," Storz says. "FAS babies are smaller, and Amanda Stovall's research provides a mechanism for how this happens—reduced vascularization of the extra-embryonic tissues."
Knowing that the embryos would be unable to survive for more than 19 days, several students puzzled over how to transport an embryo into a shell to enable it to hatch. "The chicks have to peck on something to survive," Gatewood says, "so we're going to try to pour the chick into an eggshell to see if it'll allow it to hatch. No one's ever been able to hatch a chick this way, but we're going to try."
After the observation period was complete, Gatewood and Jessica Wheeler were, at least, successful in transporting their chick back into an egg. "The heartbeat was still strong," Gatewood says, "so we put it in an incubator to monitor for a few days, although the re-plant was ultimately unsuccessful."
Just as the fetal alcohol experiment resonated with Storz as an undergrad, it has made a tremendous impact on his own students, many of whom share the belief that it is a lab they will never forget.
"To actually watch the developmental process take place has been truly awe-inspiring," Stovall says, "and it's given me an appreciation for life that I think would be difficult to get elsewhere."
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