RUI: Functional Development of an Insect Visual System

动物眼睛中的感光细胞含有从称为生色团的化合物中提取的光吸收色素。这些色素分布在感光器内紧密堆积的膜层上。膜和它们的感光色素的组装和持续的周转可能对视觉功能如光适应至关重要，但周转的作用还没有被很好地理解。这个项目利用昆虫视觉系统的特殊特性来解决这个问题。天蛾Manduca从幼虫发育成成蛾；如果幼虫的食物中缺乏发色团(与维生素A相关的化合物)，则成虫的视力严重受损。值得注意的是，人们发现，在一种特殊的溶液中，只需在成年人的眼睛上涂上这种化合物，就能部分恢复视觉敏感度。这个系统现在将被用来评估发色团是如何合成成光色素的，发色团和膜是如何相互作用的，以及光色素是如何插入到膜中的。将使用解剖学和生物化学方法检查膜的超微结构、光色素的定位和发色团的新陈代谢。这种准备提供了一种新的方法来解决视觉中的一个中心问题，并将在一组具有重要生态意义的昆虫中产生关于夜间视觉的有用信息。

Photoreceptor cells in animal eyes contain light-absorbing pigments derived from compounds called chromophores. These pigments are localized on densely packed layers of membrane within the photoreceptors. Assembly and ongoing turnover of the membranes and their photopigments may be crucial to features of vision such as light adaptation, but the role of turnover is not yet well understood. This project exploits special properties of the visual system of insects for attacking this problem. The hawkmoth Manduca develops from a larval caterpillar into an adult moth; if the larva has a diet deficient in chromophores (vitamin A-related compounds), the adult has severely impaired vision. Remarkably, simply "painting" the adult eyes with the compounds in a special solution has been found to partially restore visual sensitivity. This system now will be used to assess how the chromophore is synthesized into photopigment, how the chromophore and membranes interact, and how the photopigment is inserted into the membrane. Anatomical and biochemical methods will be used to examine the membrane ultrastructure, the localization of the photopigments, and the metabolism of chromophores. This preparation provides a novel approach to address a central issue in vision, and will yield useful information on nocturnal vision in an ecologically important group of insects.