Effects of Infiltration of Terrestrial Microbes into Aquatic Microbial Communities

Hello, all! My name is Jamie Harris and I am a rising sophomore Biology major with a minor in Public Health at the College of William and Mary.  This summer, my research in Dr. Williamson’s bacteriophage ecology  lab will deal with, as you may have noted from the title, the effects of infiltration of terrestrial microbes into aquatic microbial communities.  More specifically, I will determine the general shifts in microbial communities in William and Mary’s wet retention ponds before, during, and after, major storm events.

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The end of the summer

During this summer I have worked hard to obtain data that will be used to quantify the mutation rate of the hyper mutable region of interest in the genome of H. pylori. I have done procedures that have put me closer to inserting the hyper mutable region into the bacterium E. coli so that the mutation rates can be compared between these two bacterial species. The data gathered from the AFLP protocols done this summer have consistently shown the same number of cytosines within the hyper mutable region of interest in both the bacterial colonies and bacterial populations analyzed. It will be interesting to see if this result holds up when the bacterial environment is experimentally stressed. This will be the topic of experiments to come in the near future.

Continued Diligence

At the same time that I was doing the procedures talked about in the previous blog post, I was also continuing the procedures that lead up to the AFLP protocol. After some initial troubles with the sequencing machine that carries out the protocol, I obtained results that were consistent with results from previous AFLP protocols done. So far, each AFLP has revealed the same number of dominant poly-C lengths within each bacterial colony and population. In the future, we will try to stress the environment of the bacteria to see if the number of dominant poly-C lengths will increase or decrease due to environmental stress.

Nearing the End

During the previous week, I picked transformed E. coli colonies that were mentioned in the previous blog post. I put these colonies into media and incubated them at a temperature that would allow them to grow at optimal reproductive capacity. After approximately 24 hours of growth, I created a pellet of the cells in a centrifuge and performed a plasmid preparation procedure on the pellet. This procedure resulted in purified plasmids, on which I then performed a restriction digestion. After this I performed gel electrophoresis on the restriction digestion in order to see if the reaction worked and found out that it did. In the following day, I extracted this restriction product from the gel, and executed a procedure on it in order to purify the DNA in the product. In the future (most likely the beginning of fall semester) I will do procedures to incorporate this purified DNA product into a viral genome that will be used to infect E. coli cells in a process called transduction. During transduction, a viral vector will incorporate it’s genome, that includes the hyper mutable region of interest, into E. coli cells. Once this is done, I will begin performing the same mutation rate procedures done on H. pylori on these E. coli cells.

Girolama and the Prophage

During this summer, I will be conducting research on the Prophage portion of the J68 strain of Helicobacter Pylori. From previous research, I will continue the genome walking of this gene to determine the chromosomal insertion point of the prophage element.