Hughes C, Meynell G G
Mol Gen Genet. 1977 Mar 7;151(2):175-9. doi: 10.1007/BF00338692.
A procedure is described for demonstrating plasmid DNA and its molecular weight, based on rate zonal centrifugation of unlabelled DNA in neutral sucrose gradients containing a low concentration of ethidium bromide. Each DNA species is then visualized as a discrete fluorescent band when the centrifuge tube is illuminated with ultra-violet light. Plasmids exist as closed circular and as relaxed circular molecules, which sediment separately, but during preparation of lysates, closed circular molecules are nicked so that each plasmid forms only a single band of relaxed circles within the gradient.
本文描述了一种基于在含有低浓度溴化乙锭的中性蔗糖梯度中对未标记DNA进行速率区带离心来展示质粒DNA及其分子量的方法。当用紫外线照射离心管时，每种DNA分子都会呈现为一条离散的荧光带。质粒以闭环和松弛环分子形式存在，它们沉降时会分开，但在裂解物制备过程中，闭环分子会被切口，因此每个质粒在梯度中仅形成一条松弛环的单一带。
