1. Institute for Health Care Science and Suntory Institute for Bioorganic Research, Suntory, Ltd., 1-1-1 Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka 618-8503, Japan, Faculty of Bioresources, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-11, Japan, and Faculty of Agriculture, Kagoshima University, Korimoto 1-21-24, Kagoshima 890, Japan