MARINE CHEMISTRY WITH SPECIAL EMPHASIS ON STEROIDS

我们和其他实验室的工作表明，低等海洋动物 一个丰富的来源，结构不寻常的甾醇，其中没有对应的， 地球来源。 另一方面，这些固醇有不寻常的一面， 链--通常比胆固醇中的支链多得多 及其同系物。 将开展工作，以阐明 这些甾醇的生物合成，并确定其来源的复杂 宿主共生关系的这些海洋动物的隔离和 共生体的实验室培养。 它们的生物学功能 独特的甾醇可能与膜功能有关， 设想分离和结构鉴定磷脂 这些海洋动物似乎也有独特的脂肪酸。 将使用这些不寻常的磷脂制备模型膜，然后 比较这些海洋固醇的作用与胆固醇在这些 模型膜。 另一方面，一些海洋固醇也 拥有不寻常的核，它们的生物学作用也需要阐明。 在这里，可以再次设想膜功能，但在这种情况下， 应该反映在不寻常的头部组（而不是脂肪酸） 这些磷脂的成分。 在这些不寻常的原子核中， 一个是19-nor-环A系统，这是在 自然，即使它构成了所有合成的关键功能， 口服避孕药 另一个例子是A-去甲甾醇，其中环 A是五元的。 我们希望能阐明 这些独特的甾醇类型。 总的来说，已经有超过100种新的甾醇被发现。 在过去的几年里，从海洋资源中分离出来， 爆炸似乎仍在继续。 其中有一组甾醇 在侧链上有环丙烷环，我们相信它们可能 表示生物甲基化的交替模式中的中间体， 这是根本利益。 生物合成研究设想与 能够合成这种甾醇的单细胞生物。

Work in our and other laboratories has shown that lower marine animals are a rich source of structurally unusual sterols, which have no counterpart in terrestrial sources. On the other hand, these sterols have unusual side chains - frequently much more branched - than those found in cholesterol and its congeners. Work will be performed to elucidate the mechanism of biosynthesis of these sterols and to determine their origin in the complex host-symbiont relationships of these marine animals by isolation and laboratory culture of the symbionts. The biological function of these unique sterols is probably related to membrane function and extensive work is envisaged on isolating and structurally identifying the phospholipids from such marine animals, which also seem to have unique fatty acids. Model membranes will be prepared using these unusual phospholipids and then compare the role of these marine sterols with that of cholesterol in such model membranes. On the other hand, some of the marine sterols also possess unusual nuclei and their biological role also needs elucidation. Here again, a membrane function can be envisaged, but in this instance it should reflect itself in unusual head group (rather than fatty acid) constituents of these phospholipids. Among the unusual nuclei, a striking one is the 19-nor-ring A system, which has never been encountered in nature, even though it constitutes the key functionality in all synthetic oral contraceptives. Another example are the A-nor sterols, in which ring A is five-membered. We hope to shed light on the biological function of these unique sterol types. In summary, well over 100 new sterols have been isolated during the past few years from marine sources and this veritable explosion seems to continue unabated. Among them are a group of sterols with cyclopropane rings in the side chain and we believe that they may represent an intermediate in an alternate mode of biomethylation, which would be of fundamental interest. Biosynthetic studies are envisaged with unicellular organisms capable of synthesizing such sterols.