About Me:
My name is Rebecca Cooke. I have been teaching for the past nine years and I am currently teaching Biology, Anatomy & Physiology, Zoology, and Biomedical Science at Douglas High School.
This is my third year participating in RET. In my first year, I participated in RET where I worked to genetically engineer a bacterial plasmid with fluorescent proteins to serve as a live-dead reporter system. I was thrilled to be invited back for a second year and work with the Rao lab using photocatalysis for water treatment and hydrogen fuel production. I am looking forward to working in the Srinivasan lab this year.
About the Lab: I am working in the Systems Neuroscience Laboratory this summer, which Dr. Jagan Srinivasan runs. The lab uses C. elegans (a microscopic worm) to study how neurons interpret social signals and produce certain behaviors.
Project Title: Effects of E-cigarette Liquid on Caenorhabditis elegans Behavior
Weekly Updates:
- Week 1: This week I met several members of my lab team. Sam and I came up with a plan for how I am going to conduct my experiment. I will grow some C. elegans worms and I will feed some worms E.coli mixed with the vaping liquid. The plan is then to record avoidance assays and attraction assays to different substances to see how exposure to the vaping fluid affects the worm’s behavior. On Friday I began by seeding the worm plates and made dilutions of the vape liquid. The following week I learned how to transfer worms onto the plates so I could let them lay eggs and develop into young adults. With an existing worm plate, I learned how to wash the worms from the NGM and began practicing the mouth-pipetting technique for the avoidance assay. I am still practicing these techniques while I wait for these worms to develop. I also learned the general protocol for a chemotaxis assay. The worms like the smell of popcorn!
- Week 2: This was the first time I exposed the worms to vaping liquid. I created plates with different concentrations of the vaping liquid mixed with the worm’s food. I was also able to conduct my first successful avoidance assay with worms not exposed to the vaping solutions. I am becoming much more skilled in managing and passing worms. Unfortunately, we discovered that our vaping liquid is not sterile. Worms exposed to the vape fluid are contaminated with other microbes. Therefore it’s impossible to tell if any changes to the worms’ behavior are due to the vape or bacterial contamination. So we need to determine a new protocol for sterilizing and preparing the vape liquid dilutions.
- Week 3: This week was a bit challenging because of our setback with the contamination of the vaping liquid. Fortunately, we mitigated the contamination by autoclaving some of the vaping liquid. I completed some more chemotaxis and avoidance assays on worms unexposed to the vaping liquid but learned that I should be testing all worms on the same day over a few days. This is because their behavior could be influenced by the environment that day, such as temperature and humidity.
- Week 4: I am getting interesting results for the avoidance and chemotaxis assays. Worms tend to hate glycerol and love diacetyl. However, worms exposed to the vaping liquid show reduced sensitivity to these substances. As the vaping liquid is increased in the worm’s food, they ignore glycerol more often. I have also observed some instances of negative chemotaxis on worms exposed to 10% vaping liquid. I also learned how to bleach worms to synchronize their ages. This is an important step in the egg-laying assay because worms will slow their egg-laying as they age. I will be counting the eggs every day for five days.
- Week 5: I finished all my avoidance and chemotaxis experiments this week. I achieved statistically significant results! The effect of the vaping liquid on the worms is concentration-dependent. The more vaping liquid the worms are exposed to, the greater the changes in their behavior. I did not do enough trials to do stats on the egg-laying data, but I found that worms lay fewer eggs when exposed to the vaping liquid. Worms exposed to 1% vape, 5% vape, and 10% vape all lay roughly the same number of eggs over 5 days, less than the unexposed worms. However, there is also a delay in egg-laying at high concentrations of the vaping liquid. Most worms lay all their eggs by day 4 but some worms exposed to the 10% vape were still laying eggs on day 4.
- Week 6: This was the final week of RET. I enjoyed touring everyone else’s lab and the water sampling. I also finished up the data for my poster. Overall, I am very proud of myself. I completed 3 separate experiments on the worms while working solo in the lab. I accomplished so much in these short few weeks.
Our Final Poster: