Tsukamoto S
Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
Yakugaku Zasshi. 1999 Jul;119(7):457-71. doi: 10.1248/yakushi1947.119.7_457.
Most marine sessile organisms have a planktonic larval phase in their life cycles, and then larvae settle and metamorphose into their adult forms. The selection of settlement sites is a critical event for these organisms because settlement on unsuitable places affects their survivorship severely. Ascidians live gregariously, and conspecific chemical cues are thought to play an important role in gregarious settlement of larvae. The extracts of conspecific adults or larvae have been claimed to contain "natural metamorphosis inducers." Little is known, however, about their chemical properties. To discover natural signal substances for larval metamorphosis in ascidians, we surveyed the metamorphosis-inducing activity of the medium conditioned by ascidian larvae, and succeeded in isolating a metamorphosis-inducing substance from the conditioned medium of Halocycthia roretzi larvae and found that it was identical to lumichrome. We have also isolated more than 40 active metabolites, which may mimic lumichrome, from marine sponges. On the contrary, marine sessile organisms cause serious problems by settling on fishing nets, hulls of ships, and cooling systems of power plants. Organotin compounds have been widely used for the control of these organisms, but they are known to be toxic to marine biota. Therefore, nontoxic antifouling substances are urgently needed. Marine sessile organisms possess chemical defense systems using their secondary metabolites, which might be potential by nontoxic antifouling agents. We have attempted to obtain antibarnacle substances from marine sponges and isolated 26 antifoulants.
大多数海洋固着生物在其生命周期中都有一个浮游幼虫阶段，然后幼虫会沉降并变态为成体形态。沉降地点的选择对这些生物来说是一个关键事件，因为在不合适的地方沉降会严重影响它们的生存。海鞘群居生活，同种化学信号被认为在幼虫的群居沉降中起重要作用。同种成体或幼虫的提取物据称含有“天然变态诱导剂”。然而，关于它们的化学性质却知之甚少。为了发现海鞘幼虫变态的天然信号物质，我们调查了海鞘幼虫条件培养基的变态诱导活性，并成功地从罗氏海鞘幼虫的条件培养基中分离出一种变态诱导物质，发现它与光色素相同。我们还从海洋海绵中分离出了40多种可能模拟光色素的活性代谢物。相反，海洋固着生物在渔网、船体和发电厂的冷却系统上沉降会造成严重问题。有机锡化合物已被广泛用于控制这些生物，但已知它们对海洋生物群落有毒。因此，迫切需要无毒防污物质。海洋固着生物利用其次级代谢产物拥有化学防御系统，这些次级代谢产物可能是潜在的无毒防污剂。我们试图从海洋海绵中获取抗藤壶物质，并分离出了26种防污剂。
