Quahogs flex toxin-defiant muscle, research finds

UMass Dartmouth professor Dr. Bal Ram Singh, above right, with colleages from India, Dr. V.K. Das, center and Dr. Shobna Das.
UMass Dartmouth professor Dr. Bal Ram Singh, above right, with colleages from India, Dr. V.K. Das, center and Dr. Shobna Das.

Studies at UMass Dartmouth could lead to botulism-poisoning antidote

The next time you spoon up a stuffie, chew on this: Quahogs, the uniquely Rhode Island seafood snack, might contain an enzyme that resists botulism.

“Quahogs seem to have a resistance to diseases, and toxins in particular,” said Dr. Bal Ram Singh, a professor of chemistry and biochemistry at the University of Massachusetts Dartmouth. Singh has been trying to find out what in the makeup of a quahog makes it resist the toxin that’s fatal in humans.

“You can inject a quahog with enough botulism to kill 10,000 people … and nothing happens to it,” Singh said.

“We were very amazed and started to search for why.”

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Singh assigned a project in a biochemistry class a few years ago that required students to research a local subject.

One student decided to examine what it was that made quahogs in New Bedford Harbor resist the PCB contamination there.

“There are large quahogs that live in the harbor – she wanted to find out how they live there,” Singh said.

Researchers found an enzyme that partly breaks down the PCBs. The results from that study prompted Singh to examine the effects other toxins might have on the mollusk.

Botulism poisoning can be fatal in humans and is listed as one of the top five bioterror threats in the world, along with anthrax and smallpox. The poison blocks communication between muscles and nerves, rendering victims paralyzed. The poisoning usually leads to breathing problems, then death.

The research hit a snag when scientists working in the Dartmouth lab realized they had a limited understanding of how the quahogs’ nerves and muscles work. While exposing the mollusks to different chemicals, they quickly snapped shut.

Singh last year brought in colleagues from India to better understand the construction of the quahog. The lack of knowledge had been a major hindrance to Singh’s research.

“It took him one week to solve the whole thing,” Singh said of Dr. V.K. Das, who was able to map the nerve and muscle layout of the quahog, simplifying the research team’s task.

“Then the race was on,” Singh said.

Researchers injected the quahog again and watched closely what its response was. When it’s injected, the quahog begins releasing mucous, the tissue turns brown. The brown tissue eventually dissipates, and the quahog continues to live.

“It means the quahog is affected by the toxin, but it still didn’t die,” Singh said.

The browning tissue is made up of cells that are apparently defensive to toxins and disease, researchers found. They also learned that the blood is able to significantly reduce toxins.

Singh said researchers are confident they will eventually unlock secrets of the quahogs’ toxin-indifferent cells and then be able to develop an antidote that can be used to counteract human botulism poisoning.

People come into contact with botulism through mishandling of food or through wounds. Infants that come into contact with botulism spores can also become poisoned.

Singh said his findings don’t shed any negative light on quahogs and “if anything, this puts them in a positive light.” In fact, the resistant substance in quahogs could turn out to be beneficial if eaten, he said.

The time frame on the conclusion of the research is dependent on acquiring reasonable funding, Singh said. If that comes through, he anticipates finishing the research within a few years.