Granell A, Flores R, Conejero V
Anal Biochem. 1983 Oct 15;134(2):479-82. doi: 10.1016/0003-2697(83)90326-3.
A combination of high salt and low ethanol concentration allowed the fractionation of nucleic acids extracted from viroid-infected leaves. By adding 0.4-0.5 vol of ethanol to 1 vol of a solution in 2 M LiCl of nucleic acids (containing mainly DNA, 4S, 5S, 7S, and viroid RNAs), 85% of the DNA and 75% of the 4S RNA remained in solution, from where they could be recovered by increasing the ethanol concentration, whereas almost all 5S, 7S, and viroid RNAs precipitated. When this process was repeated three times a 95% elimination of the initial DNA and 4S RNA was achieved. The method can be of special interest in viroid purification considering that DNA and 4S RNA are the most abundant contaminants in the starting solution of nucleic acids. It is suggested that the highly ordered secondary structure of viroid RNA may be responsible for its particular behavior in the ethanol fractionation of nucleic acids.
高盐和低乙醇浓度的组合能够对从类病毒感染叶片中提取的核酸进行分级分离。向1体积含核酸（主要包含DNA、4S、5S、7S和类病毒RNA）的2M LiCl溶液中加入0.4 - 0.5体积的乙醇，85%的DNA和75%的4S RNA仍留在溶液中，可通过提高乙醇浓度从中回收，而几乎所有的5S、7S和类病毒RNA都沉淀下来。当此过程重复三次时，初始DNA和4S RNA可被去除95%。鉴于DNA和4S RNA是核酸起始溶液中最主要的污染物，该方法在类病毒纯化方面可能具有特殊意义。有人认为，类病毒RNA高度有序的二级结构可能是其在核酸乙醇分级分离中表现出特殊行为的原因。
