1. Division of Applied Science; Graduate School of Agriculture, Hokkaido University; Kita 9, Nishi 9, Kita-ku Sapporo 060-8589 Japan.
2. Department of Agricultural and Life Science; Obihiro University of Agriculture and Veterinary Medicine; Inada-cho Obihiro 080-8555 Japan.
3. Suntory Institute for Bioorganic Research; 1-1-1 Wakayamadai, Shimamoto-cho Mishima-gun, Osaka 618-8503 Japan.