The effect of small concentrations of antibiotics blocking the synthesis of bacterial cell wall on the permeability of Escherichia coli cell wall for plasmid DNA

Short treatment of Escherichia coli cells with antibiotics disturbing synthesis of bacterial cell wall in small concentrations renders the cells capable of absorbing foreign plasmid DNA. A novel express-method for transformation of E. coli cells by plasmid DNA has been developed on the basis of the results obtained. The whole procedure can be performed at room temperature. Depending on cell strain and the plasmid size, the efficiency of transformation can vary from 1.10(4) to 5.10(5) transformants per 1 mkg of DNA. The method suggested improves significantly the every-day work aimed at constructing plasmids.