[Adsorption of lambda phage DNA onto Escherichia coli cells treated with Ca2+ ions and onto frozen--thawed bacteria]

The study of the biologically active tritium-labeled phage lambda DNA adosrption on Ca2+-treated and frozen--thawed E. coli cells showed the absence of a correlation between the adsorption level and transfection efficiency. Thus the infectious phage lambda DNA adsorption level does not change, while frozing--thawing of E. coli cells but it increases ten-fold when treating the cells with Ca2+ in ice, the transfection efficiency level with this DNA being equal for both types of recipients.