Salmonella is the number one foodborne bacterial pathogen in the US. The Shariat lab(aka the CRISPR Crew) is developing a new technique that allows us to survey the diversity of this bacterium within a single sample. While we always think of chickens and eggs, it is known that Salmonella can also be found in water. For the last several months, we have been working on a project to investigate Salmonella diversity in our local rivers and creeks. What better place to start this investigation than in our very own watershed! Since all Gettysburgians know that campus is drastically different during each season,our team co
llected water samples in November and April so we could compare how those seasonal changes affected bacterial diversity. We selected 60 different sites across three different creeks – Marsh Creek, Willoughby Run, and Rock Creek.
While the rest of campus was enjoying SpringFest festivities, we headed out into the community sporting our thigh high waders, ready for a day of sample collection. Some of our locations were easy access, but we had a few exciting encounters, including meeting some snakes as they seemingly fell from the sky (or maybe just a low hanging branch) into the river next to us, plus getting stuck in some nasty mud on one river bank! We also got drenched in a mid-day deluge. All in the name of science!
In lab this summer, our main focus was processing these samples we collected to determine whether we could find any Salmonella (spoiler: don’t go swimming in our creeks, Salmonella is everywhere!). After we collected water, we had to extract DNA from the bacteria and do PCR to replicate the isolated DNA (we need a lot of DNA to do our experiments). PCR uses a lot of enzymes and other stuff that shouldn’t be in our final samples, so we had to remove these things using a REALLY POWERFUL MAGNET that is super cool and makes DNA stick to it, so you can remove everything else quickly and easily without losing the DNA. We’re currently sequencing our samples to identify exactly which types of Salmonella are present.
CRISPR Crew Cares Day
During our water collection, we noticed that the banks of some of our local creeks have a LOT of trash, so we decided to do a river clean up for our second annual CRISPR Crew Cares day. On a drizzly morning, we headed out to the historic Sachs Covered Bridge (if you haven’t visited this yet, you totally should!) that spans Marsh Creek. We spent the morning collecting trash on the bridge (which may or may not be inhabited by ghosts) and along the creek. Notable finds include computer parts, travel size liquor bottles, yards of fishing wire, and a handful of batteries.
Bacteria and a famous battle…
We recently had the opportunity to meet with Dr. Eric Brown, Director of the Division of Microbiology in the Office of Regulatory Sciences at the United States Food and Drug Administration, and members of his awesome research team. Their research program is focused on food safety – keeping pathogenic bacteria such as Salmonella out of our food chain. The research we do in the Shariat Lab focuses on effectively subtyping and identifying different kinds of Salmonella from different sources, such as the creeks surrounding campus. We had the
opportunity to share our findings with the FDA research team through student presentations and to also listen to some of their exciting research programs and discoveries they’ve made. We loved the opportunity to have such advanced conversations with experts in the field and it was cool to learn about federal research programs.
To top off an awesome day, it turns out that Dr. Brown is not only a scientist, but apparently knows more about Civil War history than the majority of Gettysburg College students! After a morning of science, the whole group headed over to the battlefield where he gave us an incredible tour of two major sites of the Battle of Gettysburg (Little Round Top and Pickett’s Charge). Other tourists even joined our group thinking that Dr. Brown was a professional tour guide! All in all, we had a lot of fun and it was an amazing opportunity.