Biopolymers and cell. 2001; 17 (2): 160 - 165

Isolation of clones sensitive to bacteriophage A from the phage resistant Escherichia coli strain

I. Yu. Slavchenko

A method of selection of the phage A sensitive clones from the population of the bacteriophage A resistant cells using the phage \cI857Ap Tc has been theoretically formulated and experimentally approved. The isolation was realized as follows. The phage A resistant E. coli strain was infected by phage A, which introduces antibiotic-resistance markers into the cell. The sensitive to phage A vir and lysing at 43 °C clones were isolated on the selective medium. The frequency of occurrence of such cells in the population was JO . The presence of ts-mutation in the phage cJ gene has allowed to cure the cells from phage XcI857Ap Tc during cultivation of these cells under non-selective conditions at increased temperature and to obtain the phage A sensitive clones originated from resistant E. coli strain. The method can also be used for the estimation of the E. coli populations heterogeneity by a given feature.