Warning lights mark shellfish that aren't safe to eat

December 15, 2010

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.

Mussels and oysters accumulate single-celled marine creatures 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.

Scientists think symbiotic bacteria that live on the surface of dinoflagellates probably help synthesize the toxins, but no one is sure how. Genetic tools 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 toxin 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.
-end-
The National Institute of General Medical Science and the American Chemical Society funded this project.

University of California - San Diego

Related Enzyme Articles from Brightsurf:

Repairing the photosynthetic enzyme Rubisco
Researchers at the Max Planck Institute of Biochemistry decipher the molecular mechanism of Rubisco Activase

Oldest enzyme in cellular respiration isolated
Researchers from Goethe University have found what is perhaps the oldest enzyme in cellular respiration.

UQ researchers solve a 50-year-old enzyme mystery
Advanced herbicides and treatments for infection may result from the unravelling of a 50-year-old mystery by University of Queensland researchers.

Overactive enzyme causes hereditary hypertension
After more than 40 years, several teams at the MDC and ECRC have now made a breakthrough discovery with the help of two animal models: they have proven that an altered gene encoding the enzyme PDE3A causes an inherited form of high blood pressure.

Triggered by light, a novel way to switch on an enzyme
In living cells, enzymes drive biochemical metabolic processes. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics.

A 'corset' for the enzyme structure
The structure of enzymes determines how they control vital processes such as digestion or immune response.

Could inhibiting the DPP4 enzyme help treat coronavirus?
Researchers and clinicians are scrambling to find ways to combat COVID-19, including new therapeutics and eventually a vaccine.

Bacterial enzyme could become a new target for antibiotics
Scientists discover the structure of an enzyme, found in the human gut, that breaks down a component of collagen.

Chemists create new artificial enzyme
Rajeev Prabhakar, a computational chemist at the University of Miami, and his collaborators at the University of Michigan have created a novel, synthetic, three-stranded molecule that functions just like a natural metalloenzyme, or an enzyme that contains metal ions.

First artificial enzyme created with two non-biological groups
Scientists at the University of Groningen turned a non-enzymatic protein into a new, artificial enzyme by adding two abiological catalytic components: an unnatural amino acid and a catalytic copper complex.

Read More: Enzyme News and Enzyme Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.