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Debra A. Meuler
Associate Professor
Biology Department
Cardinal Stritch University
Don’t Lose Your Head!: A Case Study in Dorsal-Ventral Axis Formation in Amphibians

This whimsical case introduces students to the topic of dorsal/ventral (DV) axis formation in amphibians. After the recent birth of a good-sized clutch of eggs, Heather Pipiens is pleased to see that most of her little larvae are doing fine, but alarmed to find that one has a smaller head and hasn't yet formed adhesive glands. Mr. Pipiens attempts to comfort his wife by noting that not all of their 133 healthy larvae developed at the exact same rate: "Remember Gracie? She gastrulated almost a day later than the rest and she's just fine." As the story unfolds, students learn how induction and cytoplasmic determinants coupled with other molecular mechanisms contribute to the formation of the DV axis and the embryonic body plan. Students are introduced to the basics of DV axis formation, how the organizer and Nieuwkoop center are formed, and how various genes interact to facilitate the formation of the DV axis in amphibians. The case was originally written for a course in developmental biology.

Helicobacter pylori and the Bacterial Theory of Ulcers 

This case is an account of the events that led Drs. Robin Warren and Barry Marshall to the bacterial theory of ulcers. The two physicians refused to accept the standard explanations for what they had observed and instead developed an alternative hypothesis, saving countless patients from unnecessary pain and suffering. Along the way they transformed the way the medical community viewed peptic ulcer disease. The case shows the importance of curiosity, serendipity, and tenacity in scientific inquiry; how science is built upon the work of others; how assumptions can cloud people's views, leaving them closed to new ideas; and how scientific "truth" can and does change when faced with new data and new interpretations. It is appropriate for use in any course at the high school or undergraduate level that teaches students about the scientific method and/or the sociology, nature, and history of science.

Which Little Piggy Went to Market?: Bioinformatics and Meat Science

In this case study, a scientist is contacted by a friend from a meat processing plant who is looking for a test to determine the sex of the animals that contributed to a particular batch of meat. He needs to know because meat from uncastrated males (boars) imparts an unpleasant odor (boar taint) to pork products, something he wants to avoid. Developed for use in an introductory biology class, the case introduces students to basic genetics concepts, DNA structure, the technique of PCR, genetic databases, and the use of positive and negative controls during scientific investigations. The case could also be used in high school classes, especially as a tool for learning about (or reviewing) the scientific process as it requires students to develop hypotheses, design experiments, and analyze and interpret data.