The hungry blogger aims her fork towards a plate of seafood on the lab bench in front of her when a mussel suddenly cries out, “Wait — don't eat me!”
Well, not quite. But researchers at U.C. San Diego have developed a fluorescent warning system that lights up in the presence of toxins that could lead to food poisoning for a consumer.
The toxins are produced by single-celled plankton called dinoflagellates, which oysters and mussels consume while filtering seawater. Dinoflagellates are usually harmless, but can sometimes make toxic chemicals that leach into the tissue of shellfish. And occasionally, dinoflagellates create large algal blooms, known commonly as "red tide," which poison many shellfish at once.
Chemistry professor Michael Burkhart and his team made the warning system by attaching a chemical label to the enzyme in the dinoflagellate responsible for switching toxin production "on." When the enzyme turns on, the label fluoresces. The warning glow of small blue dots can be seen under a fluorescent microscope.
The method worked both in a dish culture of dinoflagellates plus some bacteria thought to aid toxin-making in the wild, as well as in live mussels. When the researchers added antibiotics to the mix, the glow disappeared.
In time, the San Diego team hopes to be able to use the glow system as way to keep tabs on shellfish in the wild and to examine mussels and oysters sold for eating. But because fluorescent microscopes are quite large and expensive to use, the technology isn't yet widespread.
I wonder if the San Diego crew has talked to their colleagues over at U.C. Berkeley about the fluorescent microscope cell phone attachment they've developed. Maybe one day there will even be an app so that shell-fishermen will be able to test their crops for toxins from the ship deck with their smartphones.