1. Laboratory of Aquatic Natural
Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657,
Japan
2. Takehara Marine Science
Station, Hiroshima University, Takehara
Hiroshima 725-0024,
Japan
3. Misaki Marine Biological
Station, The University of Tokyo, Miura,
Kanagawa, 238-0225,
Japan