1. Laboratory of Aquatic Molecular Biology and Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
2. International Institute for Advanced Research, Matsushita Electric Industrial Co., Ltd., Hikaridai, Seika, Kyoto 619-0237, Japan
3. Department of Food Science, Kyoto Women's University, Higashiyama, Kyoto 605-0926, Japan
4. Department of Physiology, School of Medicine, Teikyo University, 2-11-1, Kaga, Itabashi, Tokyo 173-0003, Japan