STOCKHOLM (Reuters) - Two Americans and a Japanese researcher won the 2008 Nobel Prize in Chemistry on Wednesday for the discovery of a glowing jellyfish protein that makes cells, tissues and even organs light up -- a tool used by thousands of researchers around the world.

In this undated publicity photo released by Tsien Lab and the University of California, San Diego, Dr. Roger Tsien's lab created this wreath made from tubes of various fluorescent proteins that were displayed in a box with UV light shining on them. Japanese researcher Osamu Shimomura and Americans Roger Tsien and Martin Chalfie were jointly awarded the 2008 Nobel Prize for Chemistry October 8, 2008. They won "for the discovery and development of the green fluorescent protein, GFP". REUTERS/Tsien Lab/UCSD/Handout

The 10 million Swedish crown ($1.4 million) prize recognizes Japanese-born Osamu Shimomura, now of the Marine Biological Laboratory in Woods Hole, Massachusetts, Martin Chalfie of Columbia University in New York and Roger Tsien of the University of California, San Diego, for their discoveries with green fluorescent protein.

“Green fluorescent proteins allow scientists quite literally to see the growth of cancer and study Alzheimer’s disease and other conditions that affect millions of people,” said Bruce Bursten, president of the American Chemical Society.

“This protein has become one of the most important tools used in contemporary bioscience,” the Nobel Committee for Chemistry at the Royal Swedish Academy of Sciences said in a statement.

Shimomura, 80, first isolated GFP from jellyfish drifting off the western coast of North America and discovered that it glowed bright green under ultraviolet light. For 20 years from 1967, he made a summer pilgrimage to Friday Harbor in Washington state to gather more than 3,000 jellyfish per day.

Chalfie and colleagues got bacteria such as E. coli and tiny worms called C. elegans to produce the protein by splicing in the right gene.

The protein glows under blue and ultraviolet light, allowing researchers to illuminate tumor cells, trace toxins and to monitor genes as they turn on and off.

“The discovery is of great use for humanity. In the past 10 years, in almost every second publication in the big journals, people are using this method,” Lars Thelander, a member of the Nobel Committee for Chemistry, said in an interview.

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“We can simply look inside an animal and say where has this gene been turned on, when is it turned on and when the protein is made, where does it go?” Chalfie, 61, said in a telephone interview. “They have their own flashlight telling you where they are.”

Tsien, 56, a Howard Hughes Medical Institute investigator, used coral proteins too, and extended the palette beyond green to yellow, blue and other colors, allowing scientists to follow several different biological processes at the same time.

He said asthma kept him indoors as a child, so he spent hours playing with colors as part of chemistry experiments in his basement.

Chalfie said he missed the first call from the Nobel committee: “I looked on the computer, my laptop, and I found that I had won the prize. I slept through the phone call.”

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GFP has been used for art as well as for science. A green-glowing bunny named Alba was made in 2000 at the request of Chicago artist Eduardo Kac and green-glowing pigs have been gene engineered and bred to make green-glowing piglets.

No one is sure what the jellyfish use the glow for. “It’s either sex or food,” said Dr. Jeremy Berg of the National Institute of General Medical Sciences, one of the U.S. National Institutes of Health, which funded all three researchers.

“Whether they use it to commune with one another or help them hunt, I don’t know.”

The prizes were established in the will of 19th-century dynamite tycoon Alfred Nobel and have been awarded since 1901.

The laureate for literature will be unveiled on Thursday, followed by the Nobel Peace Prize on Friday and the economics award on Monday.