1. Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Bunkyo-ku, Tokyo 113-8657, Japan
2. College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
3. National Research Institute of Fisheries Science, 2-12-4 Fukuura,
Kanazawa-ku, Yokohama, Kanagawa 236-8648, Japan
4. School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan