My practicum site was at the Savannah River National Laboratory (SRNL), which is a part of the Savannah River Site (SRS), located in Aiken, South Carolina. SRS is one of 17 US Department of Energy Labs stationed around the country. I worked at the Aiken County Technical Laboratory, which is located on the campus of SRS, in the non-radiological contaminated area. I was an intern in the Bioscience Analytical Group.
My site supervisor was Dr. Robin Brigmon, a senior scientist at SRNL. However, in lab, I worked more closely with two post-docs, Dr. Alex Kugler and Dr. Nate Losey, as well as Dr. Brigmon's other intern, Jackson DeVault. I found my internship through UMD's careers for engineers emails. Over winter break, I received an email about internships at DOE National Labs. I submitted an application to intern at any national lab and heard back from SRNL in March. To future SGC students, I would recommend actually reading through the many emails you receive from your department. Often times, they will share crucial information that can help students find internships and jobs.
During my internship, I studied siderophores, a compound secreted by bacteria. To understand, some background science information is needed:
Nearly all organisms rely on iron, an essential nutrient, as it is a cofactor for enzymes and regulatory proteins that are involved in cellular processes such as energy generation and cell growth. Iron is a transition metal, that exists in the 2+ and 3+ oxidation states, with the 3+ state being more common in nature. However, the 3+ state is insoluble at a physiological state, and therefore biologically unavailable. To adapt to iron starved conditions, bacteria have evolved the ability to secrete siderophores, which are small organic chelators that fix iron from its 3+ state to its 2+ state, so that it can be used by the cell.
Cupriavidus basilensis SRS is a bacteria that has been isolated from a metal and radionucleide contaminated stream sediment at the Savannah River Site and is known to have an affinity for rare earth elements. The experiments I conducted during my internship were aimed on determining C. basilensis SRS' ability to produce siderophores.
To begin, I made a universal siderophore assay: the Chrome Azurol S assay (CAS). The CAS assay is a universal siderophore detection method. It has three components: CAS, an iron solution, and hexadecyltrimethylammonium bromide (HDTMA). These three components form a compound which is blue/green in color. When a siderophore is present, it scavenges the iron from the compound, freeing the CAS-HDTMA complex, which turns the solution yellow. In the presence of iron, the solution should become lighter colored.
To calibrate this assay, I used a known siderophore producer at various concentrations. At each concentration, I measured the amount of light that passed through the sample using a spectrophotometer. That way, when I ran my experiments, I could predict the concentration of siderophores based on the amount of light that passed through the sample. After the assay creation and calibration was complete, my daily tasks at the lab consisted of testing the siderophore production of C. Basilensis SRS in different growth conditions.
Working on this project has made me realize how widely impactful science can be for our society. Before working on the project, I would never have thought of the idea of employing bacteria as a method of extracting rare earth metals for commercial purposes. The idea of biology, geology, and electronics just seemed so utterly unrelated to one another, that I would never have assumed that they could be used together to achieve a goal. Now, it makes me ponder what other ways there might be connections between seemingly unrelated branches of science and the ways those connections could impact the way we live.
This project was my first experience working in a lab. I was pleased to find out that I truly do enjoy bench work. I always suspected that, despite my apprehension towards working in lab and the fears I had about messing up experiments, I would find the satisfaction of getting results to be enough of a motivator to pursue research. Working at SRNL confirmed this. After completing my bachelors degree, I hope to continue doing research while working on a Masters degree. After that, I hope to continue working in a lab, potentially as a pharmaceutical engineer.