Meeting Abstract
A meaningful laboratory class on biochemical methods should not only demonstrate modern techniques, but should also provide an experimental context that intellectually engages students. Our department has been using a series of laboratory exercises that provides instruction in biochemical techniques within the context of an investigation of environmental endocrine disruption. The experiments evaluate serum vitellogenin induction as a biomarker for estrogen exposure. Male African clawed frogs are treated variously with natural estrogens, environmental estrogens, or vehicle. Serum samples, prepared from the frog blood, are used for the biochemical analyses. A Coomassie protein assay is first used to compare total serum protein levels among treatment groups. Differences in serum protein compositions, based on separation by molecular weight, are then compared among groups by SDS-PAGE. Proteins from control and treated groups are then separated by DEAE-chromatography, followed by vitellogenin Western blotting analysis of the serum samples and DEAE fractions, using a specific vitellogenin antiserum. Students then interpret their data on vitellogenin induction in the context of endocrine disruption. This series of experiments has been used for a number of years in our experimental biology laboratory course, and a more limited single laboratory experiment has been used to expose high school students to biochemical methods. The experiments can be expanded to include RT-PCR analysis of hepatic vitellogenin mRNA induction, or liquid chromatography-mass spectrometry of vitellogenin. Feedback from students has been generally positive. They particularly enjoy evaluating whether or not their experimental compounds are endocrine disruptors.
