Shellfish not safe to eat marked with warning light

Dec 15, 2010 By Susan Brown
Shellfish not safe to eat marked with warning light
Blue specks rimming these dinoflagellates mark bacteria that are helping to produce dangerous toxins.

Red tides and similar blooms can render some seafood unsafe to eat, though it can be difficult to tell whether a particular batch harbors toxins that cause food poisoning.

A new kind of marker developed by chemists at the University of California, San Diego, and reported in the journal ChemComm makes it easier to see if shellfish are filled with toxin-producing organisms.

and accumulate single-celled called dinoflagellates in their digestive systems as they filter seawater for food. Usually dinoflagellates are harmless, but sometimes they produce dangerous toxins. The trick is figuring out when.

Shellfish not safe to eat marked with warning light
You can't tell by looking whether a mussel is safe to eat.

Scientists think that live on the surface of dinoflagellates probably help synthesize the toxins, but no one is sure how. often used to sort out such relationships don’t work for dinoflagellates, which have enormous genomes that are not well understood.

So chemistry professor Michael Burkhart’s group took a different approach. They set up a system to add a fluorescent tag to an enzyme that makes one kind of toxin, okadaic acid, but with a twist. By handing the tag to a the molecule that turns the enzyme on, they ensured that only those parts of cells that are capable of making the toxin would glow.

Specks glow brightly on the surface of dinoflagellates incubated with both the marker and symbiotic bacteria, and the toxin accumulates in the culture. Those lights go off, and production ceases, if the chemists add antibiotics to the mix.

The new marker proved useful in live mussels as well. Their guts glowed with toxin-producing dinoflagellates even before the poison transferred to the mussel tissue itself.

This technique may could be the basis of an early warning system for aquaculturists and in theory it could lower the risk of shellfish poisoning.

Right now, the method requires a relatively expensive fluroscence microscope to view the tagged cells, but Burkhart’s team is optimistic that rapidly developing technology will soon make the tag easy to detect with a handheld device.

Explore further: Dead feeder cells support stem cell growth

Related Stories

Cause of mussel poisoning identified

Mar 24, 2009

The origin of the neurotoxin azaspiracid has finally been identified after a search for more than a decade. The azaspiracid toxin group can cause severe poisoning in human consumers of mussels after being ...

Little creatures, big blooms

Feb 16, 2007

The San Francisco area is well-known for its beautiful waters. In fact, it is one of the most biologically productive areas in the United States’ waters.

Vibrio bacteria found in Norwegian seafood and seawater

Feb 24, 2009

(PhysOrg.com) -- While working on her doctorate, Anette Bauer Ellingsen discovered potentially disease-causing vibrios (Vibrio cholerae, V. parahaemolyticus and V. vulnificus) in Norwegian seafood and inshore ...

Scripps Oceanography Research pegs ID of red tide killer

May 01, 2008

Researchers at Scripps Institution of Oceanography at UC San Diego have identified a potential “red tide killer.” Red tides and related phenomena in which microscopic algae accumulate rapidly in dense ...

Probing Question: What is a red tide?

Feb 07, 2008

Although its name sounds like a low-budget horror movie, you won't find "Red Tide" at a theater near you. To take in this natural phenomenon, you'll have to venture to the ocean, because red tide — or more ...

Recommended for you

Dead feeder cells support stem cell growth

Apr 24, 2015

Stem cells naturally cling to feeder cells as they grow in petri dishes. Scientists have thought for years that this attachment occurs because feeder cells serve as a support system, providing stems cells ...

Improving accuracy in genome editing

Apr 23, 2015

Imagine a day when scientists are able to alter the DNA of organisms in the lab in the search for answers to a host of questions. Or imagine a day when doctors treat genetic disorders by administering drugs ...

Drug research enhanced by fragment screening libraries

Apr 22, 2015

Generation of fragment screening libraries could enhance the analysis and application of natural products for medicinal chemistry and drug discovery, according to Griffith University's Professor Ronald Quinn.

Decoding the cell's genetic filing system

Apr 22, 2015

A fully extended strand of human DNA measures about five feet in length. Yet it occupies a space just one-tenth of a cell by wrapping itself around histones—spool-like proteins—to form a dense hub of ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.