Interns Use Genetic Tools to Study Bivalve Diseases


Interns are an essential part of the Bigelow Laboratory community every summer, enriching its social life and advancing important research into the foundations of ocean health. Under guidance of Bigelow Laboratory scientists, interns spend 10 weeks conducting independent research, getting hands-on experience with state-of-the-art technologies and developing new skills in research and science communications. The program has been running since 2009, growing from eight participants in the first year to 24 in the most recent cohort — with students coming from institutions across the country.

“I like to keep in touch with them after they leave, and I’m even attending the wedding of my student from 2015,” said José A. Fernández Robledo, a senior research scientist who has long been involved with the internship program. “This experience can make a big difference in their life.” Just a few weeks back, for example, he attended the dissertation defense of a former student who credited his summer experience with sparking a “fascination” that guided him through his doctoral studies.

Bradi Sladek was an intern this summer, co-mentored by Fernández Robledo and fellow Senior Research Scientist Pete Countway, exploring genetic engineering techniques to study diseases that affect bivalves, such as clams. A marine science student at Southern Maine Community College, Sladek will be transferring to the University of Southern Maine in the fall and hopes to eventually pursue a career in research.

Sladek joined the summer program specifically to work with Fernández Robledo after learning from him during a winter short course at MDI Biological Laboratory. She and her fellow students spent the week in Bar Harbor studying a form of contagious cancer that affects clams.

“After the short course, I just thought this was so cool,” Sladek said. “Fortunately, Bigelow actively recruits students from Southern Maine Community College each summer. It’s an amazing opportunity you don’t usually have at a community college.”

Alongside Ciara Moroney, a rising senior majoring in biotechnology at Worcester Polytechnic Institute, Sladek continued the short course research studying bivalve transmissible neoplasia, a widespread contagious cancer similar leukemia that affects several commercially important species. Their goal was to test whether clams in Long Cove, Maine, are infected and to see if there is any relationship between the prevalence of the disease and environmental conditions like salinity.

The team found clear evidence that the disease is infecting clams in Long Cove, though the research is ongoing. In fact, the students’ efforts were just one piece of a multi-year, multi-institutional project surveying for the disease in Massachusetts, Maine, and along the West Coast.

“This is a whole area of research I didn’t even know about before the short course and this summer,” Sladek said. “I think I may end up doing something in pathology or biotech, which is surprising to me, but this work is just really exciting.”

In addition to her work on this project, Sladek led another effort that aimed to develop an immortalized cell line for bivalves. If successful, the technique would enable significant advances in research on bivalve parasites and diseases.

An immortal cell line is a culture of cells that divide indefinitely, allowing them to be grown in a lab for prolonged periods. Though that immortal quality can happen spontaneously — as in the famous case of the Henrietta Lacks cells that revolutionized medicine — more often, scientists use genetic engineering techniques to alter or introduce new genes that stop the cells from naturally dying.

“It’s getting more and more difficult to find clams that aren’t already infected, so if you have a cell line, you’re home free,” Fernández Robledo said. “Unfortunately, with invertebrates, and bivalves in particular, people have tried to develop one for a long time and haven’t succeeded.”

Without one, researchers have struggled to fully understand bivalve diseases. Having a cell line that can be shared between labs would allow for more consistency between studies and increase the number of experiments scientists can run, without ethical issues around using live animals.

The best effort to date for a bivalve cell line was a study published in Japan by a team that maintained a scallop cell line in the lab for a month. Sladek’s goal was to try out the technique developed by the Japanese researchers, as well as two other methods, to engineer an immortal cell line for clams and oysters.

As they developed the vehicle with which to inject these new genes, the team included a protein that fluoresces green as it spreads.

After almost nine days, Sladek looked under a microscope and saw bright green cells, evidence that the new genes had taken hold and spread. It’s still early days, but it’s an important step. Bigelow Laboratory scientists can also use these preliminary results to write research proposals to continue the work.

Summer research experiences like Sladek’s help move forward this kind of cutting-edge research, but they also have long-term benefits for the students themselves. Sladek, for example, highlights all the soft skills she gained at Bigelow Laboratory, from critical thinking and self-sufficiency to learning to work as part of a team. They’re skills that will be valuable no matter which path she takes in the future. (Except for the skills she developed navigating through thick, smelly mud to collect samples, which she doesn’t hope to use again!).

“José plays a really important and unique role as someone who helps connect students who arrive interested in, for example, public health, and exposes them to ocean science,” Vice President for Education Ben Twining said. “It gives us an entry point to students with diverse interests.”

Fernández Robledo said that his students have gone on to pursue careers, in academia and industry, across marine science, biotech, and medicine. He believes the summer internship, more than just providing training in oceanography, is valuable for giving students insight into what it is to do science.

“It’s about learning how to approach problems and how to figure things out yourself,” he said. “I always tell them that if what you’re doing works the first time, either you are a genius or what you’re doing probably isn’t very interesting.”

Photo 1: Fluorescent cells viewed under a microscope provide evidence that new genes have spread, an important first step in creating an immortal cell line for bivalves.

Photo 2: Summer intern Bradi Sladek at work in the lab.

Photo 3: Sampling bivalves in the field to extract blood and organs for experiments.

Photo 4: Students Bradi Sladek and Ciara Moroney present their findings at the end-of-summer intern poster session.