Chemical Studies on Super Carbon Cbain Compounds Produced by Dinoflagellates.

海洋生物产生具有显著生物活性的新化合物。为了明确冈田酸和泥藻毒素这两种超碳链化合物的产生者，我们对共生甲藻Acoela sp.进行了培养，得到了两种典型的超碳链化合物。对这些分子进行了结构鉴定。然而，由于这里分离的毒素是复杂的且相对较大的分子，因此尚未获得最终的结构信息。从分布于日本太平洋海岸的典型海绵Halichondria okadai Kadota中分离得到一系列软海绵素。例如，软海绵素B表现出显著的抗肿瘤活性，是抗癌药物的候选者。虽然软海绵素B已被Kishi等人完全分离，但我们仍需向临床试验提供克级的量。由于不可能从黑色海绵中获得这些物质，我们开始寻找真正的软海绵素天然生产者，因为怀疑是细菌或蓝绿藻等海洋微生物。从宿主动物中分离细菌并在海洋琼脂培养基中培养。监测这些培养基的抗真菌活性导致我们分离脂肽，如伊枯草菌素和plipastatin。

Marine organisms produce novel compounds with remarkable biological activitites. Our studies have been carried out in order to clarify the true producers of the super carbon chain compounds such as okadaic acid and palytoxin.The symbiotic dinoflagellate isolated Acoela sp. was cultured to give us two typical super carbon chain compounds. The structure elucidation of these molecules has been carried out. However, the final sturctural information has not yet obtained because the toxins isolated here are to be complex and relatively large molecule. From the typical marine sponge, Halichondria okadai Kadota distributed on the rocky Pacific shores of Japan, we isolated a series of halichondrins. For example, halichondrin B exhibits remarkable antitumor activity and is a candidate of anticancer drugs. Although halichondrin B has been totally sunthesized by Kishi's group,we have to supply the amount of gram-scale toward clinical test. Since it is impossible to obtain those from the black sponge, our search for the true natural producers of halichondrins has started because marine microorganisms such as bacteria or blue-green algae are suspected. Bacteria were isolated from the host animal and cultured in marine agar medium. Monitoring antifungal activities of these cultured medium led us to the isolation of lipopeptides such as iturin and plipastatin.