Osamu Shimomura
Discovered a jellyfish protein which transformed cell science
OSAMU SHIMOMURA, who has died aged 90, survived the bombing of Nagasaki to share the 2008 Nobel Prize in chemistry, with two American scientists, for the discovery and development of a jellyfish protein called Green Fluorescent Protein (GFP), routinely used by scientists to track biological processes such as nerve cell damage in Alzheimer’s disease or how cancer cells develop and spread.
Shimomura, who inevitably became known as “Dr Jellyfish”, was born at Fukuchiyama, Kyoto, Japan, on August 27 1928, the son of an officer in the Imperial Japanese Army, and brought up in Manchuria and Osaka. His education was cut short during the Second World War when he was mobilised to work at a munitions factory not far from Nagasaki.
When the atomic bomb detonated on August 9 1945, he was briefly blinded by a flash of light and felt the pressure wave from the explosion. Walking home, he was drenched with black rain, which his grandmother insisted he wash off, probably saving him from radiation-related illness.
But he remembered seeing the bodies of victims piled high and the experience changed his life: “I totally lost any desire to become famous or rich. All my worldly ambitions were gone.”
After the war he studied at a local pharmacy college and later worked as a lab assistant at Nagoya University, where he was given a project which had defeated researchers at Princeton over many years – to discover what made a crushed seed shrimp, Cypridina, glow when moistened with water.
After 10 months of getting nowhere, one night Shimomura “accidentally’’ left the compound in a strong acid: “Next morning, I found the dark red mixture was turned into a colourless transparent solution.’’ The solvent had crystallised into pure, fine red crystals yielding a protein that glowed 37,000 times more brightly than the crushed crustacean.
After publishing the results, in 1959 he was invited by the American marine biologist Frank Johnson to work in his Princeton laboratory. There, the two men began catching and cutting up specimens of the crystal jellyfish, also known as Aequorea victoria, which is plentiful off the west coast of North America and which glows green around the edges when agitated.
Shimomura reckoned that in all they caught and cut up around a million of the creatures, extracting a liquid that they called a “squeezate”, but the fluorescent chemical involved proved elusive.
One day, after a summer of fruitless effort, he tossed some of the jellyfish extract into a sink where seawater from an aquarium had just been poured. The calcium in the water caused a protein within to glow blue for the first time outside the living animal.
Shimomura succeeded in extracting the luminescent substance aequorin, which glows blue, but realised that something else was converting the blue light into the green glow jellyfish emit. Eventually he isolated a second protein, later known as GFP, which was able to absorb both blue light and ultraviolet light and then fluoresce green.
For the next 17 years Shimomura continued to harvest jellyfish and in 1979 he published the chemical structure of GFP, laying the groundwork for further research by his fellow Nobel Prize winners, Martin Chalfie and Roger Tsien, who built on his work to make GFP a vital tool in biomedical laboratories.
The Swedish Academy described GFP as “a guiding star for biochemists, biologists, medical scientists and other researchers” and compared its impact to the invention of the microscope.
Later, Shimomura moved to the Woods Hole Oceanographic Institution and was an adjunct professor at the Boston University School of Medicine.
He and his wife Akemi had two children.
Osamu Shimomura, born August 27 1928, died October 19 2018