1. Faculty of Fisheries Sciences, Hokkaido University, Hakodate 041-8611, Japan
2. Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, Illinois 60611
3. Instrumentation Analysis Center, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
4. Suntory Institute for Bioorganic Research, Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka 618-8503, Japan