[Differential isolation of low-molecular plasmids]

Several methods for the isolation of plasmid DNA from Yersinia pseudotuberculosis have been tried; the aim of the study has been a differentiated isolation of low-molecular plasmids from natural strains of bacteria containing plasmids with various molecular masses. The modifications of the known methods have been developed, that rule out the use of lysozyme for cell lysis and permit prepare clarified lysates containing mostly low-molecular plasmid DNA from natural strains of bacteria containing high-molecular plasmids as well.