Modest Nobel laureate says Japan deserves his prize

"I was just an obscure researcher," he told a news conference in the western city of Kyoto.

"I thought from the bottom of my heart that without the support of the country, I could not have been awarded this wonderful prize," he said. "I literally feel that the country of Japan won the award."

Yamanaka and Britain's John Gurdon were jointly honoured for discovering that adult cells can be transformed back to an infant state called stem cells, the key ingredient in the vision of regenerative medicine.

"Their findings have revolutionised our understanding of how cells and organisms develop," the Nobel jury declared. "By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy."

Yamanaka said he wants to intensify efforts to put his findings to practical medical use. "My joy is great but at the same time I feel great responsibility," he said.

The Japanese was singled out for his work in the field of so-called induced pluripotent stem (iPS) cells. "iPS is still a new technology," he said.

"We have yet to say this actually can help develop new medicine. I really feel that I have to realise a medical application and contribute to society as soon as possible."

Prime Minister Yoshihiko Noda congratulated Yamanaka. "I sincerely respect his award and as a Japanese I'm proud of it," he said in a statement.

(c) 2012 AFP