STOCKHOLM (AFP) - Osamu Shimomura of Japan and US duo Martin Chalfie and Roger Tsien on Wednesday won the Nobel Chemistry Prize for a fluorescent protein derived from a jellyfish that has become a vital tool in research. Green fluorescent protein (GFP) has revolutionised lab work in medicine and biology, enabling scientists to get a visual fix on how diseases spread in mice and lab-dish cells or whether cells respond to treatment, the Nobel jury said. "GFP has functioned in the past decade as a guiding star for biochemists, biologists, medical scientists and other researchers," it said. "This protein has become one of the most important tools used in contemporary bioscience." The gene to make GFP is inserted into the DNA of lab animals, bacteria or other cells, where it is "switched on" by other genes. The glow becomes apparent under ultraviolet light. The telltale gives researchers an instant way of monitoring processes that were previously invisible. By tagging nerve cells, scientists can for instance follow the destruction caused by Alzheimer's disease. Or by adding GFP to a growing mouse embryo, they can see how the pancreas produces insulin-producing beta cells. In one spectacular experiment, researchers made a "brainbow," in which they tagged different nerve cells in the brain of a mouse with a kaleidoscope of colours. Shimomura, born in 1928 and now a professor emeritus at Marine Biological Laboratory (MBL) and Boston University, pioneered this tool with a study of the jellyfish Aequorea victoria in the 1960s. He isolated a few precious grams of luminescent liquid from 10,000 jellyfish, which led to the discovery that its source was GFP, a so-called chromophore " a chemical group that absorbs and emits light. Chalfie, born 1947 and a biology professor at Columbia University, followed up on Shimomura's research. He helped identify the gene that created GFP and found ways of using it in a common lab tool, the millimetre-long roundworm called Caenorhabditis elegans. Tsien, born 1952 and a professor at the University of California, completed the final step, developing new variants of GFP that shine more strongly and in different colours, allowing researchers to mark different proteins in different colours to see their interactions. Last year Gerhard Ertl of Germany won the prize for work that has become invaluable to the modern chemical industry and helped fight to fix the ozone hole. On Monday, French and German scientists credited with the discovery of the viruses behind AIDS and cervical cancer won the Medicine Prize, the first of the prestigious awards to be announced this year. The Physics Prize was awarded on Tuesday to Makoto Kobayashi and Toshihide Maskawa of Japan and Yoichiro Nambu of the United States for groundbreaking theoretical work in fundamental particles. The Literature Prize will follow on Thursday, while the Peace Prize will be announced in Oslo on Friday. The Economics Prize will wrap up the awards back in Stockholm on October 13. Laureates receive a gold medal, a diploma and 10 million Swedish kronor (1.42 million dollars, 1.02 million euros) which can be split between up to three winners per prize. The formal prize ceremony will be held as tradition dictates on December 10, the anniversary of the death in 1896 of the prize's creator, Swedish industrialist and inventor of dynamite Alfred Nobel. The prizes were first awarded in 1901.