ONOMICHI, HIROSHIMA PREF. – This fall, Osamu Shimomura, a Nobel laureate in chemistry known for his research on jellyfish, was on an island in the Seto Inland Sea that he often visited five decades ago to catch another luminous organism: sea fireflies.
The professor emeritus at Boston University was awarded the 2008 Nobel Prize in chemistry along with two American scientists for the discovery of green fluorescent protein in a jellyfish called Aequorea victoria.
But Shimomura, 85, said in an interview during his short stay in Japan that it was sea fireflies that laid the foundation for his becoming a chemist.
In late September, Shimomura visited Kone Island in Onomichi, Hiroshima Prefecture, for the first time in about 50 years to take part in an event organized by local residents to observe sea fireflies.
Sea fireflies are crustaceans measuring 3 mm in length and resemble water fleas. They produce a blue light.
Shimomura explained to some 60 participants how he trapped sea fireflies 50 years ago — sinking into the water a cooking bowl covered by a cloth with a small hole in its center and bait inside.
“It was like a star,” Kansuke Morimoto, a local 11-year-old, said after watching a sea firefly glowing blue.
In 1956, Shimomura became the world’s first researcher to succeed in crystallizing luciferin, the luminescent substance in sea fireflies, when he was a research student at Nagoya University.
American researchers had been trying in vain to do so for more than 20 years.
“That success offered hope for my future, which had looked gray ever since the end of World War II,” Shimomura said. “I was so excited and happy that I wasn’t able to sleep at night.”
Shimomura started going to Kone Island because he needed more sea fireflies to continue his research and clarify the mechanism of bioluminescence.
He posted ads in newspapers to seek information on which waters sea fireflies inhabited. He then received a letter from Samon Miyamoto, a junior high school science teacher, at a local junior high school, telling him about the local habitat.
In the late 1950s to early 1960s, Shimomura frequented Kone and Ikuchi islands, which are next to each other, and collected sea fireflies together with Miyamoto’s brother, Hajime, and other island residents.
“Those days are such great memories,” Shimomura said.
Believing that his successful research into sea fireflies had secured his future, Shimomura flew to the U.S. in 1960 to become a researcher at Princeton University, which eventually led to his winning the Nobel Prize.
During his September visit, Shimomura went to a coastal graveyard to pay his respects to the Miyamoto brothers and other residents who helped him catch sea fireflies.
“I owe them a lot and feel like I was able to repay their favors by winning a Nobel,” Shimomura said. “I hope they are pleased by it.”