New Antibiotic Found in Fish

RALEIGH, North Carolina, November 15, 2001 (ENS) - A new antibiotic isolated from fish may have implications for treating diseases in both humans and animals, say the North Carolina Sea Grant researchers who discovered it. The study is reported in today's issue of the journal "Nature."

Named piscidins after the Latin term "pisces" for fishes, the antibiotics were isolated from mast cells in hybrid striped bass. Mast cells are the most common tissue immune cell found in fish and other vertebrates, including humans. They are present in many tissues, including the skin, gills, and gastrointestinal tract.

This is the first time that researchers have isolated a peptide antibiotic from the mast cells of any animals, including humans. However, it is unclear whether fish mast cells are from the same lineage as mammal mast cells.

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A hybrid striped bass - source of the first antibiotic isolated from a mast cell (Photos courtesy Ronald Hodson, North Carolina Sea Grant, NCSU)
"The peptide antibiotics or piscidins have the potential to fight important bacterial pathogens of both fish and mammals, including multi-drug resistant bacteria," said Ed Noga, professor at the North Carolina State University College of Veterinary Medicine, and head of the research team that made the discovery.

"The antibiotics could be a useful template for designing new drugs because they are novel structures and not related to any known and currently used antibiotic," noted Noga. "With the development of antibiotic resistant bacteria, there is an urgent need to find new types of antibiotics that can fight these resistant pathogens."

North Carolina Sea Grant director Ron Hodson points out that the research has tremendous potential for human medicine as well as aquaculture and other areas of veterinary medicine.

"We believe this discovery is the beginning of a whole new approach to treating bacterial diseases in humans and animals," said Hodson.

The study also has important implications for the United States aquaculture industry, which grew from $45 million in value of products sold in 1974 to over $978 million in 1998, according to the U.S. Department of Agriculture.

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Harvesting hybrid striped bass in North Carolina
The North Carolina Department of Agriculture and Consumer Services reported that the state's aquaculture sales exceeded more than $20.5 million in 2000. Hybrid striped bass was the third highest producing product in the state's aquaculture industry, generating more than $5.3 million.

"The new discovery can lead to ways to protect hybrid striped bass and other fish against disease without using traditional antibiotics," said Noga. "This may result in health costs savings and a higher quality and safer product."

Noga said the next step is to identify mast cells in other animals, including humans, that contain antibiotics.

"While mast cells are one of the most common immune cells of vertebrates, their role as a critical line of defense has been uncertain," said Noga. "However, if any type of peptide antibiotic is also present in human mast cells, it could have important implications for treating human diseases, including asthma, skin allergies and certain types of arthritis, because of the prominent role that mast cells play in these diseases."

"We hope to find an answer within the next 12 months," he added.

North Carolina State veterinary medicine graduate student Umaporn Silphaduang, a winner of the 2001 Walter B. Jones Memorial Award in Coastal and Ocean Resource Management, collaborated with Noga on the study, which was funded by North Carolina Sea Grant, the U.S. Department of Agriculture and the Binational Israel-U.S. Agricultural Research and Development Fund.