Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Bunkyoku, Tokyo 113, Japan
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060, Japan

Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Bunkyoku, Tokyo 113, Japan

Zoological Institute, Faculty of Science, The University of Tokyo, Bunkyoku, Tokyo 113, Japan

Zoological Institute, Faculty of Science, The University of Tokyo, Bunkyoku, Tokyo 113, Japan

First Department of Internal Medicine, Faculty of Medicine, The University of Tokyo, Bunkyoku, Tokyo 113, Japan

First Department of Internal Medicine, Faculty of Medicine, The University of Tokyo, Bunkyoku, Tokyo 113, Japan

First Department of Internal Medicine, Faculty of Medicine, The University of Tokyo, Bunkyoku, Tokyo 113, Japan

Department of Biophysics and Biochemistry, Faculty of Science, The University of Tokyo, Bunkyoku, Tokyo 113, Japan