Hook S L, Sanders E J
J Cell Physiol. 1977 Oct;93(1):57-67. doi: 10.1002/jcp.1040930109.
The surfaces of cells from the early embryo of the chick were examined using electron microscope techniques for the visualization of concanavalin A-binding sites. Horseradish peroxidase and Ferritin labelled concanavalin A were used to determine the distribution of the binding sites. All surfaces of the epiblast and hypoblast layers which were accessible to concanavalin A showed the presence of binding sites in stage 1 embryos. The ventral surface of the epiblast showed a high lectin affinity which may reflect the development of a basal lamina on this surface. The individual hypoblast cells at this stage showed a non-uniform distribution of binding sites, having a greater affinity on the dorsal surface than the ventral. By the time of primitive streak formation (stage 4-5) the dorsal surface of the epiblast displayed increased binding sites, while the frequency of sites on the ventral surface of the endoblast was reduced. The latter may reflect a change from one cell population to another, which occurs in the lower layer of the embryo at this time. No consistent correlation could be drawn between changes in motility of cells actually invaginating through the primitive streak and changes in affinity for concanavalin A. An overall increase in affinity of the dorsal surface of the epiblast was revealed by Ferritin and may reflect the changes in surface structure occurring in readiness for the morphogenetic migrations of gastrulation.
利用电子显微镜技术检查了鸡早期胚胎细胞的表面，以观察伴刀豆球蛋白A结合位点。用辣根过氧化物酶和铁蛋白标记的伴刀豆球蛋白A来确定结合位点的分布。在1期胚胎中，伴刀豆球蛋白A能够接触到的上胚层和下胚层的所有表面都显示有结合位点。上胚层的腹面显示出高凝集素亲和力，这可能反映了该表面基底膜的发育。此时单个下胚层细胞的结合位点分布不均匀，背侧表面的亲和力大于腹侧。到原条形成时（4-5期），上胚层的背侧表面显示出结合位点增加，而内胚层腹侧表面的位点频率降低。后者可能反映了此时胚胎下层中发生的从一个细胞群体到另一个细胞群体的变化。实际通过原条内陷的细胞运动变化与伴刀豆球蛋白A亲和力变化之间没有一致的相关性。铁蛋白显示上胚层背侧表面的亲和力总体增加，这可能反映了为原肠胚形成的形态发生迁移所做准备时发生的表面结构变化。
