Conversion Immersion Revisited:
A Fictional Scenario May Make All the Difference

Mariëlle Hoefnagels and Mark Walvoord
University of Oklahoma
hoefnagels@ou.edu and oumadfrog@ou.edu

For the 2004 ABLE annual meeting, we decided to try an unconventional type of major workshop: a "Conversion Immersion" in which experienced instructors would put their heads together and work to convert conventional "cookbook" labs into a more investigative format. We do not see ourselves as experts at doing these conversions. In fact, our motivation for organizing this major workshop was our frustration at how difficult they were!

Our role was simply to coordinate the workshop. A few weeks before the meeting, we collected cookbook labs from people who were signed up for the workshop. We summarized the labs and organized them into groups of related activities. On the day of the workshop, we divided the participants into groups of four or five and assigned each group a set of related labs. The participants spent about half of the workshop working in their groups, brainstorming and summarizing their ideas for making the labs more investigative. Then each group reported its ideas to the rest of the workshop participants. The morning session had 23 participants; the afternoon session had 15, including two especially enthusiastic "repeat customers" from the morning session.

The next volume of ABLE's Proceedings will include a summary of the workshop participants' suggestions for improving all labs considered in the workshop. This short Labstracts article presents a few that all share a trait we found especially compelling: the use of a fictional scenario to set the stage for a lab. We include these here because we think you may be able to implement them without a major restructuring of the lab. Instead, a simple adjustment in how you approach the lab's activities may make a big difference in student interest. In this brief article, we highlight ideas for improving labs on fermentation, DNA isolation, pGLO transformation, and the early development of the chick.

Fermentation

In the original lab procedure, students follow seal yeast cells in an airtight flask with a glucose solution. As fermentation proceeds, they measure carbon dioxide in the gas and test for ethanol in distillate collected from the incubation mixture. Students also estimate the concentration of glucose before and after the incubation period.

The group working on this lab suggested introducing the lab by presenting a case study, such as a bakery that can’t get its dough to rise, or a brewery that needs to make beer quickly for a competition. Instructors could then challenge the class with the question: how could you make the fermentation go faster or produce more carbon dioxide or more ethanol? Students can then devise their own hypotheses. They could change the species, brand, or amount of yeast; the amount or type of sugar (e.g. sucrose, ribose, fructose, glucose); incubation pH; salt concentration; or fermentation temperature. The product of the lab could then be a written or oral report to the brewer or baker, recommending improved procedures for beer or bread production.

Thanks to Mary Schaeffer, Amy Marion, Robert Grammer, and Jane Caldwell for your ideas.

DNA Isolation

In the original lab procedure, students isolate nuclear DNA from wheat germ using a standard protocol. They also determine the effects of making various changes in the protocol (e.g. remove the protein, test the effect of incubation temperature, omit the detergent, etc.).

The group suggested that the lab should challenge students to compete to achieve some objective. For example, the instructor might ask students to suppose a company had hired them to perfect their DNA isolation protocol. The question might become “How do you get as much purified DNA as possible from a sample?” The class could then look at a variety of DNA isolating protocols, identify the common steps, explain what each step is for, and consider which variables might affect purity and yield. Each group of students could then choose a DNA isolation protocol, select one or more variables to alter within the protocol, and design an experiment to test the effect of the variable(s) on DNA purity and yield.

Thanks to Jenny Knight, Helene d’Entremont, and Sonya Lawrence for your ideas.

Genetic Engineering: pGLO Transformation in Bacteria

In the original lab procedure, students follow a defined series of steps to introduce the pGLO plasmid into E. coli cells and then plate the cells (+ pGLO or – pGLO) on agar containing different antibiotics. After observing the results of different treatments, students calculate transformation efficiency.

The group suggested three scenarios that would help give students a context for the steps in transformation.

• You have been hired by a biotechnology company, and your first job is to improve the frequency of transformation of their E. coli cells. Which steps in the transformation protocol could you alter to improve the method? Background research is important here for two reasons. First, it will help students better understand the protocol. Second, this protocol already has low transformation efficiency, so blindly omitting certain steps will yield nothing.
• The label has been washed off your two tubes of plasmid DNA. How would you find out which plasmids you have? (This lab would focus on the use of antibiotic markers to differentiate between plasmids, but the students would have to transform E. coli to figure out what each plasmid is.)
• It may be possible to create two different plates of bacteria that both have been transformed with pGLO, but one glows more than the other. Students could then investigate factors that influence the glowing intensity in the cells (e.g. cell density, age of culture).

Thanks to Sue Karcher, Melody Neumann, and Mark Walvoord for your ideas.

Early Development of the Chick

The objective of the original lab is to introduce students to the post-gastrulation chick embryo. Students crack eggs containing live 3-day embryos and remove the embryos from the yolk. They observe specific structures and remove the amnion. Subsequently they use the dissecting microscope to identify many features of a fixed 33-hour embryo and compare the features to those of a 48-hour embryo.

The workshop group suggested that students should become invested in the lab’s outcome during the week before the lab. For example, they could work in teams to create a concept map of all the factors that contribute to chick embryonic development: oxygen; humidity; hen’s exposure to antibiotics, pesticides, or insecticides (or the same chemicals injected into the egg); hen’s diet; egg incubation temperature; carbon dioxide levels, etc. Then, each team could decide on a treatment to investigate and design an experiment with a treated and control egg. The students could then investigate both the normal (control) embryo and how the parts change in the treated egg.

Thanks to Michelle Edgcomb, Michael Killian, and Marshall Darley for your ideas.

Parting Thoughts ...

Coordinating this workshop was extraordinarily rewarding. Many participants told us they really enjoyed cooperating and brainstorming together; indeed, the energy in both sessions was evident. In response to the many positive comments we received, we hope to repeat the Conversion Immersion experience at the ABLE 2005 meeting. We hope you can join us!

Finally, we also hope that the workshop participants not mentioned here do not feel ignored. That is certainly not our intention. Rather, in this brief article we wanted to show how the lab's context can make all the difference in student involvement and excitement in a lab procedure. We hope that you will read the full account of this workshop, including all of the wonderful ideas that the participants generated, in the upcoming volume of Proceedings.