http://www.digitaljournal.com/article/352895

The glowing eel can help assess blood toxins

Posted Jun 22, 2013 by Tim Sandle
The Japanese freshwater eel is the only vertebrate known to produce a fluorescent protein. This protein is the basis of a new test to assess dangerous blood toxins that can trigger liver disease.
Japanese eel Anguilla japonica
Japanese eel Anguilla japonica
opencage
The Japanese freshwater eel (Anguilla Japonica) is commonly known as Unagi and, for most people, it is more commonly found on sushi menus (where it is served as part of unadon, where the eel is served with teri sauce.). The eel is found in Japan, Korea, China, Taiwan, and Vietnam
The eel has a remarkable property: it glows under certain types of light. This is due to a fluorescent protein produced by the eel’s muscle fibers (the eel glows green when blue light is shone on it). There are no other known vertebrates which fluoresce: other known fluorescent proteins have come primarily from jellyfish, corals, and microorganisms.
According to a paper published in the journal [i]Cell[/i], the protein has been called UnaG, for unagi green protein. What is of interest about the protein is that it fluoresces only when bound with a naturally occurring small molecule found in the eel’s muscles called bilirubin.
In people, bilirubin is produced by the breakdown of haemoglobin (it is yellow in color). Too much bilirubin in the blood can be toxic and it can be a sign of a problem with liver function and in relation to conditions like jaundice and anemia.
According to Nature, the researchers have used UnaG’s fluorescent properties to design a more sensitive, accurate, and speedier assay for bilirubin levels. This should lead to faster and improved diagnosis of liver diseases in hospitals.