Headshot of Gunter Campbell
Author: Gunter Campbell | Major: Civil Engineering | Semester: Spring 2025
My name is Gunter Campbell. I am a senior Civil Engineering student working under Dr. Wen Zhang to assess the fate of antibiotic resistance genes in wastewater treatment plant processes. I am doing research in the Spring of 2025. In May, I will graduate from the College of Engineering and plan to start working full time as a transportation engineer at the Garver engineering firm in North Little Rock, Arkansas.
Throughout the semester, my goal for research was to extract DNA from samples of wastewater and run a qPCR test on the extracted DNA to determine the amount of specific DNA gene copies I had in the samples.
I first familiarized myself with the lab. This included completing safety training for Hazardous waste, procedural steps, and how to work the autoclave. I was shown the different freezers in use at the lab. The freezers are set at different temperatures to accommodate different purposes and materials. I got an understanding of the locations of the equipment and tools I would use.
The work I did in the lab required me to be sufficient at using a pipette tool. This meant I needed to practice pipetting different amounts of liquid, so I could feel comfortable when working with the samples and the DNA. I practiced with 2, 10, 100, and 1000 microliters of water.
After enough practice, the PhD student I was working under, Samia Parveen, went to a local wastewater treatment plant in Fayetteville, AR, to retrieve our wastewater samples. We sampled using the grab method and did so after five of the treatment processes. These included grit removal, activated sludge, clarification, filtration, and UV treatment. The amount we retrieved from each location was 500 milliliters.
After sampling, I completed DNA extraction using an Omega test kit. I used the instructions provided to extract the DNA from the sample water. This included a couple of weeks’ worth of work, in which I created three samples in micro centrifuge tubes from each sample we took from the treatment plant. In total, I created 15 samples of extracted DNA.
The next thing to do was to use a qPCR test to isolate the specific target gene and determine the amount of DNA in the samples. My target gene was tetA. A qPCR test is a quantitative polymerase chain reaction test. This uses the functions of DNA replication to estimate the number of chain copies in the sample initially. This meant I had to create a mix that would promote DNA replication within the test. Using pipettes, I created a mix using supermix, primers, and water. I then added the DNA to the mix within a PCR plate. After doing all the pipetting, I sealed the PCR plate and placed that into the qPCR machine.
The machine is a real time thermal cycler. This means the temperature within the machine changes rapidly to accommodate for the specific stage of DNA replication. After the machine finished, it provided me with values so that I could use them to interpolate the amount of gene copies within the sample.
I found this research topic through my mentor, Dr. Zhang. She is currently overseeing many research projects, but looking at antibiotic resistance genes in wastewater treatment plants felt like a more pressing matter in terms of Global health. Dr. Zhang provided information and the necessary tools needed to do this research.
The primary challenge I faced when doing this research was to minimize contamination when doing the qPCR test. I had to rerun the procedure multiple times before I got good, non-contaminated data.
This was the last semester of my research, so the semester also included drafting my thesis paper and defending it in front of a committee of professors.