RUDZINSKA M A, PORTER K R
J Biophys Biochem Cytol. 1955 Sep 25;1(5):421-8. doi: 10.1083/jcb.1.5.421.
The macronucleus in Tokophrya infusionum is composed of numerous Feulgen-positive chromatin bodies (about 0.5 micro in diameter) which appear in thin sections as a dense spongework, homogeneous throughout. The same appearance characterizes metaphase chromosomes of higher forms. Some chromatin bodies of the macronucleus were found to possess a highly organized structure in certain old organisms. This structure appears in cross-sections as a honeycomb and in longitudinal sections as parallel lines about 120 A in diameter evenly spaced (about 230 A). As far as is known this is the first time a regular structure has been found in bodies of chromosomal character at the dimensional level presently explored by electron microscopy. The demonstration that OsO(4) can preserve order in chromatin material is another significant aspect of these findings.
点滴钟形虫的大核由众多孚尔根阳性染色质体（直径约0.5微米）组成，在薄片中呈现为致密的海绵状网络，整体均匀一致。高等生物中期染色体也具有同样的外观特征。在某些老龄生物中，发现大核的一些染色质体具有高度有序的结构。这种结构在横切面上呈蜂窝状，在纵切面上呈直径约120埃、间距均匀（约230埃）的平行线状。就目前所知，这是首次在电子显微镜探索的尺寸水平上，在具有染色体特征的物体中发现规则结构。这些发现的另一个重要方面是，证明了四氧化锇能保持染色质物质的有序性。
