When microbiologist Yoshinori Ohsumi told his wife, Mariko, that he was awarded this year's Nobel Prize in physiology or medicine Monday evening, she didn't believe him.

Her mischievous, sake-loving 71-year-old husband often teases her by telling an innocent lie.

"I thought he was trying to fool me again. I was really surprised when I found it was true," she said during a news conference Tuesday with her husband at the Suzukakedai campus of the Tokyo Institute of Technology in Yokohama.