[1] Univ Tokyo, Grad Sch Agr & Life Sci, Lab Aquat Nat Prod Chem, Bunkyo Ku, Tokyo 1138657, Japan
[2] Japan JEOL Ltd, Akishima, Tokyo 1968558, Japan
[3] Nagoya Univ, Sugashima Marine Biol Lab, Toba, Mie 5170004, Japan
[4] Hiroshima Univ, Takehara Marine Sci Stn, Takehara, Hiroshima 7250024, Japan