Kavenoff R, Bowen B C
Chromosoma. 1976 Dec 16;59(2):89-101. doi: 10.1007/BF00328479.
Membrane-free folded chromosomes were purified from log-phase cultures of Escherichia coli and prepared for electron microscopy by aqueous (Kleinschmidt and Zahn) spreading. The appearance of the chromosomes depended on the salt concentrations in spreading. At certain salt concentration, the chromosomes resembled rosettes, with supercoiled loops of DNA radiating from a central core containing RNA. The rosettes support previous models deduced from physical studies of folded chromosomes. Apparently, cores contain must of the visible RNA, and the organization of the core is linked to the organization of the DNA loops.
从大肠杆菌对数期培养物中纯化出无膜折叠染色体，并通过水性（克莱因施密特和扎恩）铺展法制备用于电子显微镜观察。染色体的外观取决于铺展时的盐浓度。在特定盐浓度下，染色体类似玫瑰花结，DNA的超螺旋环从含有RNA的中心核放射状伸出。这些玫瑰花结支持了先前从折叠染色体的物理研究中推导出来的模型。显然，中心核含有大部分可见RNA，并且中心核的组织与DNA环的组织相关联。
