Chemical signals involved in lethality and metamorphosis of marine invertebrates

本研究旨在阐明Heliozoa在对海洋无脊椎动物的致命活动和变态过程中所产生的化学信号。对多毛体、无根生物有诱导变形作用，对轮虫有致死性作用。从提取物中纯化出具有这些活性的化合物。结果表明，该诱导因子与从多毛鱼管团中分离出的诱导因子相同。这些化合物被鉴定为DHA和其他不饱和脂肪酸的单甘油酯。饱和脂肪酸衍生物对多毛体无活性。从MeOH提取物中获得的一个分数仅在光照条件下显示出致死活性。因此，在对轮虫或卤虾的致死活性指导下，纯化了该组分。在纯化的馏分中发现了几种叶绿素衍生物和类胡萝卜素。叶绿素衍生物酚a仅在光照条件下表现出致死活性，而类胡萝卜素衍生物玉米黄质则没有这种活性。根据所获得的事实，具有致命活性的化合物被认为是光敏剂，如磷化物衍生物。虽然所需的化合物还没有被分离出来，但这些事实强烈地提出了海洋无脊椎动物之间化学信号的一个重要方面。嗜磷酸盐的衍生物来源于Heliozoa喂养的微藻，由Heliozoa合成。

This research was carried out to clarify chemical signals produced by Heliozoa being involved in the lethal activity toward marine invertebrates and the metamorphosis. The MeOH extracts of the Heliozoa was found to show a metamorphosis-inducing activity toward a polychaeta, a sessile organism and a lethal activity against the rotifer. From the extract was purified to isolate compounds showing these activities. The metamorphosis-inducing factor was indicated to be identical with that isolated from the tube clumps of the polychaeta. The compounds were identified to be mono glyceryl esters of DHA and other unsaturated fatty acids. The derivatives of saturated fatty acids were inactive toward the polychaeta. One fraction obtained from the MeOH extract showed the lethal activity only under the light conditions. Thus the fraction was purified guided by a lethal activity toward the rotifer or the brine shrimp. Several chlorophyll derivatives and carotenoids were found to be present in the purified fractions. Pheophorbide a, a chlorophyll derivative, exhibited a lethal activity only under the light conditions, whereas zeaxanthin, a carotenoid derivative did not show such an activity. Based on the fact thus obtained, the compounds with letal activity were suggested to be a photo-sensitizer such as pheophorbide derivatives. Although the desired compounds were not isolated yet, these facts strongly proposed an important aspect on the chemical signals between marine invertebrates. The derivatives of pheophorbide were originated from the micro algae fed by the Heliozoa but being synthesized by this organism.