Rambourg A, Leblond C P
J Cell Biol. 1967 Jan;32(1):27-53. doi: 10.1083/jcb.32.1.27.
Periodic acid-silver methenamine, a fairly specific technique for glycoprotein detection, was used to stain a variety of rat tissues, in the hope of confirming the existence of a carbohydrate-rich "cell coat" at the surface of mammalian cells. It was found that nearly all cells are coated by a thin layer of stained material. Around fibrocytes and migrating blood cells, the layer is uniform and merges with the ground substance. In the nervous system, cells and processes are surrounded with a layer whose density increases in synaptic clefts. Around epithelial cells, the layer outlines apical microvilli, follows lateral interspaces, and extends between cells and basement membrane. The layer is continuous with the middle plate of desmosomes and can be followed within the wide portion of terminal bars. In contrast, staining usually vanishes when two adjacent plasma membranes fuse to form tight junctions. These findings indicate that the stained layer is a "cell coat" located outside the plasma membrane. Since the cell coat is also stained by colloidal thorium, a technique for detection of acidic carbohydrates, this structure presumably contains not only glycoprotein(s) but also acidic residues. The carbohydrates may play a role in holding cells together and in controlling the interactions between cells and environment.
高碘酸-银甲胺法是一种检测糖蛋白相当特异的技术，被用于对多种大鼠组织进行染色，以期证实哺乳动物细胞表面存在富含碳水化合物的“细胞被”。结果发现，几乎所有细胞都被一层染色物质所覆盖。在纤维细胞和游走的血细胞周围，这层物质均匀一致，并与基质融合。在神经系统中，细胞及其突起被一层物质所包围，该层在突触间隙处密度增加。在上皮细胞周围，这层物质勾勒出顶端微绒毛，沿着侧向间隙延伸，并在细胞与基底膜之间延伸。这层物质与桥粒的中间板相连，并且在终末横栏的宽阔部分也能追踪到。相比之下，当两个相邻的质膜融合形成紧密连接时，染色通常会消失。这些发现表明，染色层是位于质膜外的“细胞被”。由于细胞被也能被胶体钍染色（一种检测酸性碳水化合物的技术），因此这种结构可能不仅含有糖蛋白，还含有酸性残基。碳水化合物可能在使细胞黏附在一起以及控制细胞与环境之间的相互作用中发挥作用。
