1. National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan, Nippon Gene Co., Ltd., 1-8-7 Toiyamachi, Toyama, Toyama 930-0834, Japan, and National Food Research Institute, 2-1-12, Kannondai, Tsukuba, Ibaraki 305-8642, Japan