Associated Press Writer
CHEYENNE, Wyo.—Here's something cooler than a canary in a coal mine: Tadpoles genetically engineered to glow when they encounter water pollution.
African clawed frog tadpoles modified with jellyfish genes show promise as a faster and less expensive way to detect pollution than traditional methods, say a University of Wyoming professor and researchers in France.
What's more, the green-glowing tadpoles indicate whether pollution exists in a form that can be absorbed by an organism and therefore might be dangerous to people. That's more difficult with conventional methods.
"We're tracking dosages that would show up in terms of development in either a person or a tadpole," said Paul Johnson, a physics and astronomy professor at the University of Wyoming.
Some tadpoles have been engineered to light up in response to metals. Others fluoresce when exposed to pollution from plastic that might cause health problems by mimicking the hormone estrogen.
Water samples from the environment, such as downstream from a power plant, are put into a specially designed, two-tank aquarium that draws tadpoles into a tight space so their fluorescence can be measured. "That turns out to be nontrivial," said Johnson, who worked on the aquarium. "Tadpoles aren't just going to sit still while you measure them. They're usually off and running."
Scientists shine a blue light-emitting diode on the tadpoles and measure their fluorescence with a camera. Johnson said he has obtained a patent on that part of the system.
So how did a physics and astronomy professor get involved with tadpoles, of all things?
"My philosophy is to do whatever science is A, fun, and B, fundable," Johnson quipped.
The scientists in France are from the Museum National d'Histoire Naturelle, the utility Electricite de France and a company called WatchFrog. They did the genetic engineering.
Some of the latest research involved tadpoles modified to detect pollution from metals such as copper. The methods were published recently in the American Chemical Society journal Environmental Science and Technology.
Already the researchers are looking to future applications. For example, the tadpoles could detect toxins in food. Food could be rendered into a liquid and put in the aquarium, said Jean-Baptiste Fini with the museum.
Also, future tadpoles could be modified to fluoresce different colors depending on the pollution they encounter. Certain coral, for example, could supply genes to make tadpoles fluoresce red, said Barbara Demeneix, co-founder and chairwoman of the WatchFrog scientific council.
"Not only are we developing tadpoles that have different colors, but we are also doing tadpoles that can detect two or maybe three different chemicals at the same time by using green and red and blue simultaneously in the same tadpole," Demeneix said.