Shellfish disease research takes team approach

Professor David Rowley and graduate student Hilary Ranson

David Rowley
URI College of Pharmacy
Professor; chemistry
RI INBRE SURF program mentor

Rhode Island STAC awards

2012 STAC grant: New Tools and Mechanisms to Combat Aquaculture Diseases. The project sought to develop new tools to promote animal health in aquaculture by building on recent discoveries of marine bacteria that demonstrate impressive protective properties against disease. The objective was to develop new commercial products to promote fitness and prevent disease for finfish and shellfish in aquaculture facilities.
Collaborators: David Rowley, David Nelson and Marta Gomez-Chiarri, URI; Dale Leavitt and Roxanna Smolowitz, RWU

2014 STAC grant: Molecular Basis for Pathogenesis in the Oyster Pathogen, Roseovarius Crassostreae. Oyster aquaculture is expanding in Narragansett Bay, but this economic endeavor is threatened by a variety of pathogenic infectious agents including the causative agent of Roseovarius oyster disease (ROD). Warming waters that stress the host have led to devastating ROD outbreaks, which have resulted in some cases in losses of oyster seed of greater than 90 percent. This project combined the talents of a molecular biologist, a natural products chemist and a shellfish pathologist to seek a better understanding of ROD in order to better manage the disease.
Collaborators: David Nelson, URI; David Rowley, URI; Roxanna Smolowitz, RWU

What started out years ago as informal conversations over lunch between two University of Rhode Island (URI) professors continues to evolve and grow today as a broad, multi-disciplinary collaboration that taps into the expertise of the Rhode Island NSF EPSCoR community.

weareriepscor-2Interested in the chemical ecology of marine microorganisms, Pharmaceutical Sciences Professor David Rowley says he and Professor Marta Gomez-Chiarri, department chair, Fisheries, Animal and Veterinary Sciences, began talking about how they might explore microbial interactions in oysters.

In these early discussions, Rowley and Gomez-Chiarri recognized their effort could benefit from involving Professor David Nelson, cell and molecular biology, and director of the URI Genomics and Sequencing Center, a RI EPSCoR core facility.

Where Nelson provides a background in marine pathogenic microbes and Gomez-Chiarri in the prevention and management of infectious diseases in cultured and wild shellfish and finfish, Rowley describes his role as seeking to understand the molecules that mediate the interactions between potentially beneficial and harmful bacteria.

“Bacteria communicate with one another, using chemical language,” Rowley explains. “These molecules are signals either for cooperation within a population or they can tell another microbial organism, ‘Hey, this is our territory, back off.’”

The group expanded beyond URI to bring in biology Associate Professor Dale Leavitt, and Assistant Professor Roxanna Smolowitz, both at Roger Williams University. Leavitt’s work centers on shellfish and Smolowitz, director of the RWU Aquatic Diagnostic Laboratory, on aquatic veterinary science.

In 2012, the team won a Rhode Island Science and Technology Advisory Council (STAC) grant to support their pursuit of better aquaculture health. (The annual STAC grants provide the state match to the National Science Foundation EPSCoR Track-1 award.)

From that early seed funding, the researchers have gone on to secure larger grants from other agencies to further their investigation of how probiotics (healthy bacteria) work, methods for delivery of probiotics in shellfish hatcheries, and the application of probiotics to prevent early mortality syndrome in shrimp. A 2014 STAC grant with Nelson and Smolowitz helped kick off the probiotics research, and Nelson, Gomez-Chiarri and Rowley secured additional grants from Rhode Island Sea Grant, United States Department of Agriculture, and the Northeast Regional Aquaculture Center.

“By understanding these mechanisms, we can better predict where we can find the next set of probiotics and how to best use them,” Rowley explains. “In addition to discovering microbes that have protective effects against disease and understanding how they exert that, we also want to figure out how to deliver these organisms in the hatchery so farmers can protect their animals.”

The atmosphere has created multiple collaborations between the various groups involved as well as among the students. And, the pooled talent has attracted more researchers to join, both from within Rhode Island and beyond state borders.

Rowley says, in general, the discovery of novel molecules to treat infections interests him, carrying implications for human health and reducing the reliance on traditional antibiotic drugs. As in aquaculture, introducing a microbe into a situation takes a preventative approach rather than a reactionary measure with antibiotics, which also promotes drug resistance.

The researchers started out with small laboratory experiments, taking larvae from oysters and other shellfish and exposing them first to the helpful probiotics and then to the harmful pathogenic microbe. The success of the probiotic protection led to scaling up the experiment from just a few milliliters of seawater to a larger, nearly commercial-sized endeavor.

Rowley says the process comprises both basic and applied science: “What’s really exciting is the translational aspect to it — to take promising experiments from the bench and translating them into real world settings, to develop tools to solve problems.

“We have ever more people on this planet and we are going to need to feed them. Aquaculture is part of the solution.”

Consequently, along with developing tools and devising new methods, Rowley notes the need exists to bring more people into the industry, training students at the undergraduate and graduate level to be scientists in the marine aquaculture field. This, he says, has led to one of the best outcomes of the collaboration — student involvement and experience.

The weekly combined lab meetings provide a unique setting for the sharing of research and review of the latest results.

Rowley says the atmosphere has created multiple collaborations between the various groups involved as well as among the students. And, the pooled talent has attracted more researchers to join, both from within Rhode Island and beyond state borders at institutions in Maine (University of Maine) and Virginia (Virginia Institute of Marine Science). This, in turn, fuels the interdisciplinary approach and makes the growing team more competitive for grant applications.

“I knew about the project and I knew I wanted to work on it. It’s a close collaboration and a lot of different expertise. … This is where science is going — you can’t be a one-trick scientist anymore.”

For Hilary Ranson, a grad student in Rowley’s lab who just completed her first year, the chance to work on the probiotics project offered exactly the experience she sought in medicinal chemistry and pharmacology.

Having earned her undergraduate degree at Newcastle University, United Kingdom, Ranson first served as an intern at the Marine Biological Laboratory in Woods Hole, Mass., and then gained a research assistantship at the Oceanographic Institute there, conducting discovery work with natural products. She came to URI, she says, because it is one of the few schools to offer the medicinal chemistry and marine natural product option in pharmacy.

“I knew about the project and I knew I wanted to work on it,” Ranson says of the shellfish probiotics research. “It’s a close collaboration and a lot of different expertise. Working in a group helps you to be more well-rounded and provides a lot of mentors. This is where science is going — you can’t be a one-trick scientist anymore.”

In her role in the Rowley lab, Ranson seeks to isolate naturally occurring bacteria from lobsters to determine if any can provide a natural defense mechanism against shell disease. She also is working with shrimp and oysters. Her overall focus is on finding the chemistry of what produces the protective effects in shellfish.

Ranson says the project resonates with the direction of current research into the microbiome of the gut and how an individual’s bacterial makeup can dictate health; colonizing the gut with probiotic bacteria can lead to greater resistance to certain pathogens.

She says she is drawn to the research for the science and for her love of the ocean: “We’re using nature to guide us in developing drugs and treatments, staying away from antibiotics. We can harness the power of nature to cure disease.”

Story and photo by Amy Dunkle | RI NSF EPSCoR