Why Some Animals Glow

Marc Zimmer uses salamanders like this one, along with mice and fish, to show students that chemistry is cool. Under ultraviolet light, white mice glow green and red and fish go from gray to bright orange and yellow.
Geneticists engineered the animals to have fluorescent proteins in their cells, a harmless process that entertains (and educates) the students in Zimmer's early morning chemistry class at Connecticut College.

The glowing pets help Zimmer explain his research on bioluminescence, a natural phenomenon in which living organisms convert chemical energy to light energy. In the lab, Zimmer is trying to make fluorescent proteins that glow longer and brighter.
Many species are bioluminescent. Most are marine organisms, but some — such as the firefly and the glow-worm — live on land. They fluoresce for many different reasons: to spook predators, lure prey, attract mates and even communicate.
For scientists, one of the most famous glowing creatures is the jellyfish. For centuries, fisherman off the coast of North America noticed that some jellyfish gleamed in the water. When researchers looked closer, they found small organs along the rim of the jellyfish that sparked green pinpricks of light. In 1962, scientists identified a protein called GFP (for green fluorescent protein) that helped the jellyfish glow an emerald green.
Today, bioengineering has enabled GFP to light up a wide range of critters that help scientists watch and understand biological processes. What researchers have learned could help improve our health by advancing treatments for cancer and diabetes.
But there's more! Researchers engineered bacteria with GFP so they fluoresce in the presence of bioterrorism agents like anthrax, and they hope to add it to agricultural crops so they glow when they need water.
Read more about Zimmer's work in the fall issue of Findings magazine. And Zimmer's Web site "glows" with even more cool info about GFP!