1. Graduate School of Frontier Biosciences; Osaka University; 1-3 Yamadaoka, Suita Osaka 565-0871 Japan
2. Department of Food Science and Nutrition, Faculty of Human Life and Science; Doshisha Women's College of Liberal Arts; Kyoto 602-0893 Japan
3. Quantitative Biology Center, RIKEN; 1-3 Yamadaoka, Suita Osaka 565-0871 Japan