Watts studying fish response to chemical dispersant

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Genes that encode different stress-response proteins — proteins that protect against a stressor — are essential for the survival of a cell under attack. This is true for any animal, including fish exposed to oil or chemical dispersant as a result of the 2010 BP Deepwater Horizon oil spill.

Stephen Watts and his research team are investigating the effect the dispersant used in the cleanup of 2010 Gulf oil spill has on bull minnows. 

Stephen Watts, Ph.D., professor of biology, and his team of researchers are investigating the threshold at which Gulf bull minnows show an inflammatory response to Corexit®, the dispersant used to clean the 2010 oil spill. Watts hopes that information will lead to the development of new technologies to monitor the health of animal populations in the event of another disaster.

“Even low, non-lethal levels of chemical byproducts can negatively affect animal health and well-being,” Watts says. “There is a significant amount of research on crude oil exposure on marine species, but minimal research on the direct effects of dispersants. The extreme amount of dispersant used in the Gulf spill requires more examination.”

Watts, who has researched fish and other marine animals for 30 years, selected the bull minnow because of the extensive database on the killifish and because it can easily be manipulated in the lab — much like the freshwater zebrafish he has studied extensively for the past four years.

It was Watts’ recent research on the zebrafish that yielded groundbreaking results he says have aided in the Corexit research project.

Watts and his colleagues found that detection of elevated biomarkers like mRNA or protein levels in zebrafish would provide an early warning that contaminants are present in the environment. Their research showed that these biomarkers, known as acute phase biomarkers, represent the first-stage response of any organism to an environmental stressor. These biomarkers, which are definitive markers of inflammatory stress, have only recently been evaluated in any fish species.

Watts demonstrated the effect in zebrafish and detected an increase in mRNA for C-reactive protein (CRP), serum amyloid A (SAA) and vitellogenin — markers that are important in diagnosing human problems, including heart disease.

“If these proteins are elevated, it indicates you have inflammation somewhere — not necessarily disease, but a potential enhancer for disease onset,” Watts says. “Our job was to go in and find out if these similar types of markers are found in fish like the zebrafish and the bull minnow, and they are. These fish have the identical inflammatory markers that humans have. CRP is present. Serum amyloid A is present. Vitellogenin is present. That means we could perhaps measure them.”

Next, the researchers attempted to artificially inflame the markers in zebrafish to make the levels elevate with omega 6 lipids.

“It had an extraordinary effect,” Watts says. “You could use other types of compounds and get a dramatic initiation of some of these acute response proteins.

Locating the point at which inflammation occurs is crucial. While inflammation does not indicate disease onset, long-term response might be poor health, disease, poor reproductive success, weight loss and other issues. The ability to measure the inflammatory response in a timely manner could save marine life in future disasters.

Watts hopes technology being developed at UAB will enable workers to detect the elevated proteins of affected organisms in wild populations.

“We hope that the next time something like this happens and they see that first sheen of oil coming in, they might be able to go in and grab a couple of fish and test real quickly to see if they are being exposed,” Watts says. “Then they can take steps to protect them. This could be a future marker, and it’s something no one else has looked at.”

Testing Corexit

Watts is five months into his 12-month project, and he has tested several components of Corexit that have been bought individually from chemical companies to find the level of concentrations that induce an inflammatory response.

He has made multiple requests with Nalco Holding Company — the producer of Corexit — for a sample to test.

“The Alabama Marine Environmental Science Consortium has asked that it be given to them so they can make sure the right people get it, but they’ve gotten nothing so far,” Watts says. “We do understand their concerns from a legal standpoint. We’re still hopeful, however.”

Based on what his current research of Corexit components has yielded, he doesn’t believe the levels used in the spill will be an issue to the bull minnow. Watts does believe, however, that there is some level of the dispersant that will induce inflammation.

“But it’s very doubtful that the levels that were used were fatal to the fish or even induced inflammation,” Watts says. “I’ve looked at the chemical components of the Corexit, and these components are relatively non-toxic. But we want to see just how low of a concentration we can go until we can eliminate any stress effects on the fish.”

BP has released $450 million for additional Gulf research, and Watts is working in concert with investigators from Texas A&M, LSU, West Florida and South Florida to assemble a consortium to do long-term studies on animals that live on the ocean floor.

The institutions are putting together a grant to submit in July. UAB’s component would be approximately $300,000 a year if funded.

“We’re joining this consortium to evaluate some of the invertebrate fauna that inhabit the nearshore communities, and we’re hoping to study those for a three-year period,” Watts says. “We want to see if there was any effect of the oil spill and compare the data we collect with the historical data sets we’ve had for 20 years. We’ve got historical data that shows what we can normally expect, and we can compare that to any new data we could collect.”

The success of the UAB program is largely due to a collaboration of CAS and the School of Medicine. Collaborators at UAB include Alex Szalai, Ph.D., (Immunology); Mickie Powell, Ph.D., (Biology); Vithal Ghanta, Ph.D., (Biology); and doctoral graduate student Melissa Pegues (Immunology).

The project is funded in part by a $25,645 grant awarded by the Alabama Marine Environmental Science Consortium.