Reaction between isolated lambda phage DNA and membrane structures of Escherichia coli cells

The saccharose density gradient (30--55%) centrifugation technique applied to E. coli membrane preparations was used to show that treatment of the bacteria with Ca2+ in the cold results in the redistribution of the absorbed phage DNA from the cell wall to the cytoplasmic membrane while freezing-thawing of the bacteria leads to equal distribution of the infectious DNA among all membrane fractions. Quantitative estimation of such a redistribution is reported.