ROLE OF SUGARS IN PHAGOCYTOSIS OF ROD OUTER SEGMENTS

视网膜生理学的一个关键方面是视网膜色素沉着的吞噬作用 视杆外段视盘上皮在视杆更新过程中脱落。 与这一过程相关的分子事件知之甚少。我们会 研究一种假设，即细胞膜上的碳水化合物成分 这些细胞器与细胞的识别现象有关 视网膜色素上皮作为其吞噬的一个方面。 首先，我们将通过以下方式研究碳水化合物识别的模型系统 通过研究细胞进行吸附过程的能力 碳水化合物组成不同的糖蛋白的内吞作用。 这些研究的生物学工具将是有色上皮细胞。 胚胎雏鸡，在培养中保持；目标分子将是一个 碳水化合物类型不同的125I-新糖蛋白系列 目前，以及碘化的，纯化的溶酶体酶已建立 它们被其他细胞摄取的标记。这些研究可能会揭示 在视网膜色素上皮细胞的识别系统中 含有特定碳水化合物的糖蛋白的内吞作用。 这些研究的第二阶段将调查有色人种 上皮细胞，在培养过程中，吞噬牛棒外节、盘 膜和视紫红质脂质体，以及对这一过程的影响 通过化学和酶的方法修饰他们的碳水化合物。特别强调 会对修饰视紫红质的碳水化合物的效果产生影响 这些膜。 将使用生化、同位素和电子显微镜技术来 跟随这些反应。

A key aspect of retinal physiology is the phagocytosis by the retinal pigmented epithelium of rod outer segment discs shed during the process of rod-renewal. Little is known of the molecular events associated with this process. We shall investigate the hypothesis that carbohydrate components on the membranes of these organelles are involved in recognition phenomena with the cells of the retinal pigmented epithelium as an aspect of their engulfment. Initially, we shall examine a model system of carbohydrate recognition by these cells by investigating their ability to carry out the process of adsorptive endocytosis of glycoproteins which differ in their carbohydrate composition. The biological tool for these studies will be the pigmented epithelium cell of the embryonic chick, maintained in culture; the target molecules will be a series of 125I-neoglycoproteins which differ in the type of carbohydrate present, as well as iodinated, purified lysosomal enzymes with established markers for their uptake by other cells. These studies may reveal the presence in the retinal pigment epithelial cell of recognition systems for the endocytosis of glycoproteins involving specific carbohydrates. The second phase of these studies will investigate the ability of the pigmented epithelium cell, in culture, to engulf bovine rod outer segments, disc membranes, and rhodopsin-liposomes, and the influence on this process of modifying their carbohydrates by chemical and enzymatic means. Special emphasis will be placed on the effect of modifying the carbohydrates of rhodopsin in these membranes. Biochemical, isotopic, and electron-microscopic techniques will be used to follow these reactions.