Dr. Miyawaki from the RIKEN Brain Science Institute in Wako, Japan and colleagues have identified the first example of a muscle protein in Japanese freshwater eels (Anguilla japonica) that fluoresces under special circumstances that may lead to improved medical testing (photo above). The researchers have isolated the protein they named UnaG (after "unagi", the term for freshwater eel in Japanese). What is unique about this protein is that it fluoresces under low oxygen conditions and when it binds to bilirubin, a byproduct of hemoglobin that is a common marker physicians measure for liver health. Therefore, the discovery of this new protein may lead to better medical testing for bilirubin.
The muscle protein also fluoresces when exposed to blue light, which is how food chemists Seiichi Hayashi and Yoshifumi Toda from Kagoshima University in Japan discovered it in the popular sushi meat.
Kumagai A, Ando R, Miyatake H, Greimel P, Kobayashi T, Hirabayashi Y, Shimogori T, Miyawaki A. A Bilirubin-Inducible Fluorescent Protein from Eel Muscle. Cell. In Press.
I love Unagi, but I'm not sure about fluorescent eel. It's sure pretty to look at!