Kondo H
J Ultrastruct Res. 1984 May;87(2):124-35. doi: 10.1016/s0022-5320(84)80072-6.
The polyethylene glycol (PEG) method revealed that model systems such as erythrocytes and protein solutions, which are supposed to lack structured components, exhibit lattice structures not unlike the microtrabeculae. The compactness of the lattice was dependent on the concentration of proteins. The gelated state of gelatin exhibited lattices more compact than those of the solated state at any given concentration. Comparison of images by PEG and rapid-freezing, deep-etching replica methods showed no basic differences in the ultrastructure of the intestinal epithelial cell. This indicates that the PEG method, including chemical fixation, produces little, if any, disorganization of the cytoskeleton. All of the present findings suggest that cytoplasmic protein, nonstructure-bound or structure-forming, might be present in intact cells which could form microtrabecular structures when specimens are fixed by chemical fixatives without any extractions. Therefore, the microtrabeculae should generally be regarded as a simple marker for the presence of proteinaceous macromolecules. It is also suggested that the microtrabecular lattice, as a whole, might represent a gelated state in a given compartment when another, looser lattice is simultaneously present in the same compartment, i.e., within a single cell.
聚乙二醇（PEG）法显示，诸如红细胞和蛋白质溶液等被认为缺乏结构化成分的模型系统，呈现出与微梁结构并无二致的晶格结构。晶格的致密程度取决于蛋白质的浓度。在任何给定浓度下，明胶的凝胶状态所呈现的晶格都比其溶胶状态的晶格更为致密。通过PEG法以及快速冷冻、深度蚀刻复型法对图像进行比较，结果表明肠上皮细胞的超微结构并无根本差异。这表明包括化学固定在内的PEG法对细胞骨架造成的紊乱极少，即便有也微乎其微。目前所有的研究结果均表明，完整细胞中可能存在非结构结合型或结构形成型的细胞质蛋白，当标本用化学固定剂固定且未进行任何提取时，这些蛋白可能会形成微梁结构。因此，微梁通常应被视为蛋白质大分子存在的一个简单标志。还有研究表明，当同一隔室内（即单个细胞内）同时存在另一种较为松散的晶格时，微梁晶格作为一个整体可能代表了该隔室内的一种凝胶状态。
