doc w/ Pen

One thing I have learned about “being” in science is that it involves poster presentations. Some people like them, some people hate them, but they are a part of the job. I saw my mentor and supervisor at UIC, Olga, make several posters (to present at various conferences) while I was working there. And for the Drosophila genetics conference, Dr. Kreher made one as well (which I wrote about earlier, and which included me as a secondary author!).

Today, I will present my first and very own poster at Dominican University’s “Undergraduate Research, Scholarship, and Creative Investigations Expo” (“URSCI” for short). This is an annual event at Dominican, where students from across different disciplines present their research work through both presentations and posters. For the poster portion, which is what I am doing, you have a designated time that you are supposed to stand by your poster and explain it / answer questions about it to anyone who is interested. While this might make some people nervous, I am really excited about the opportunity. I love talking about science (obviously), and I am also adept at explaining it in more basic language for people who might not be familiar with the concepts or procedures. That is one thing I learned well in journalism – you have to know your audience. So I know how to tailor my explanation, based on the people with whom I am talking.

The title of my poster is “Antibiotic Resistance of E. coli to Rifampicin and the Mutagenic Effects of Caffeine.” The work stems from a project I did in my Research Methods in Molecular Biology class, which I took last spring with Dr. Kreher. (I am currently working in his genetics lab with the fruit fly larvae.)

It was a fascinating project, and it had two components. As a class, we reproduced the experiments done in the late 1980s by two researches, Jin and Gross. They investigated how E. coli develop antibiotic resistance to a drug called rifampicin, which is used for tuberculosis. Based on their research, and previous work, they determined that rifampicin inhibits the bacteria’s RNA polymerase (which is what transcribes mRNA, which is later used to synthesize proteins). That’s bad for the bacteria, because without the necessary cellular proteins, the bacteria will die. But Jin and Gross also discovered that the bacteria can develop, at a particular rate, specific mutations in the gene (rpoB) encoding for a particular subunit of its RNA polymerase. These mutations allow the bacteria to survive treatment with rifampicin.

We repeated Jin and Gross’s experiments, growing E. coli on agar plates containing rifampicin (as well as another antibiotic, carbenicillin, to which our bacteria had been engineered with a resistance gene, so that only the bacteria we were studying would grow – no random bacteria from the environement would grow, because the carbenicillin would kill it). We were able to generate resistant bacterial colonies as well, and sequenced their DNA. In comparing the sequenced DNA to the wild-type rpoB (RNA polymerase) gene, we found some of the same nucleotide mutations as Jin and Gross, as well as a couple of mutations that were unique to our experiments.

The second part of the project was to choose a substance – any substance within reason, that could be procured at a store or from a chemical supply company – and see how that affected the mutation rate. Each student (there were eight of us in the class) had to choose something different. I chose to work with caffeine, which is a suspected mutagen, based on some scientific literature that I found. So my hypothesis was that treating the bacteria with caffeine would increase the rate of mutation, and hence the rate of antibiotic resistance. I tested two concentrations of caffeine, 1 mg/mL and 3 mg/mL. What I found was very interesting – not only did the caffeine fail to increase the mutation rate, it actually (especially at the higher concentration) killed much of the E. coli! So I did some more literature research, and found that caffeine has been shown to also have an antimicrobial effect on E. coli. Who would’ve thought?!

I absolutely love science. You don’t always get what you expect, in terms of results (I certainly didn’t), but you usually learn something. And that’s the point: discovery.