Morphometry of cupromeronic blue-stained proteoglycan molecules in animal corneas, versus that of purified proteoglycans stained in vitro, implies that tertiary structures contribute to corneal ultrastructure.
Morphometry of cupromeronic blue-stained proteoglycan molecules in animal corneas, versus that of purified proteoglycans stained in vitro, implies that tertiary structures contribute to corneal ultrastructure.
复制标题
动物角膜中铜色蓝染色的蛋白多糖分子的形态测定与体外染色的纯化蛋白多糖分子的形态测定表明，三级结构有助于角膜超微结构。
作者：
J. Scott
从牛、兔角膜和牛巩膜中分离纯化的硫酸软骨素（皮肤色素）小蛋白聚糖，用铜丙二酸蓝进行模型实验。将图像的长度和厚度与组织中染色的相同蛋白聚糖的图像进行比较，使用临界电解质浓度原理来确定硫酸盐蛋白聚糖的特异性，并使用角化酶1或软骨素酶ABC消化来区分软骨素和硫酸角蛋白聚糖。对切片平面内染色的聚糖丝的方向进行校正，以将观察到的长度转换为真实的平均长度。在模型和组织中，观察到的染色硫酸软骨素（皮肤色素）的长度大于硫酸角蛋白的长度，这与两种物种的生化和旋转阴影研究发表的数据一致。校正后的（真实）染色分离硫酸软骨素蛋白聚糖的平均长度比旋转阴影或生化测量的预期长度略长，但并不显著。硫酸角檀的长度也同样稍长。这些数据支持了这样一种观点，即铜质子蓝作为一种支架，帮助维持聚阴离子的形状，防止染色时的扭曲。组织中染色的纤维有时超过分离的染色蛋白聚糖长度的两倍，表明2个聚糖链是端到端排列的。蛋白聚糖细丝的厚度表明，在模型和组织中至少有2条聚糖链并排排列。提出了角膜中蛋白聚糖三级结构的方案，其中聚糖链可以桥接胶原原纤维的双相形式，类似于在旋转阴影制剂中观察到的那些。
Isolated, purified small chondroitin (dermatan) sulphate proteoglycans from corneas of cow and rabbit and cow sclera were stained with Cupromeronic blue in 'model' experiments. The lengths and thicknesses of the images were compared with those of the same proteoglycans stained in the tissue, using the critical electrolyte concentration principle to give specificity for sulphated proteoglycans, and keratanase 1 or chondroitinase ABC digestion to distinguish between chondroitin and keratan sulphate. Corrections for orientation of the stained glycan filaments within the section plane were made to convert the observed lengths to true average lengths. Observed lengths of stained chondroitin (dermatan) sulphate were greater than those of keratan sulphate, both in models and tissues, in agreement with published data from biochemical and rotary-shadowing studies, in both species. Corrected (true) average lengths of stained isolated chondroitin (dermatan) sulphate proteoglycans were slightly, but not significantly, longer than expected from rotary shadowing or biochemical measurements. Keratan sulphate lengths were similarly somewhat longer. The data support the idea that Cupromeronic blue acts as a scaffold that helps maintain polyanion shape against distortion on staining. Stained filaments in tissues were sometimes over twice the length of isolated stained proteoglycans, suggesting that 2 glycan chains were aligned end-to-end. Thicknesses of proteoglycan filaments suggested that at least 2 glycan chains were aligned side-by-side, both in models and in tissues. A scheme for proteoglycan tertiary structure in cornea is proposed, in which glycan chains may bridge collagen fibrils in duplexed forms similar to those observed in rotary shadowed preparations.