The Metabolic Activities of Escherichia coli during the Establishment of Lysogeny

Abstract

SUMMARY: Escherichia coli strain K112 was infected with λ phage (multiplicity of input 20 particles/cell) in 0·02M-MgSO₄, and 91% infected cells gave the lysogenic response. When the infected cells were transferred to a complete amino acid medium containing ¹⁴C-DL-phenylalanine and a non-utilizable inducer for β-galactosidase, the net synthesis of protein and nucleic acids did not begin until after 100–120 min. During this period there was no induced synthesis of β-galactosidase (though the enzyme was readily developed in uninfected cells) and there was no increase in turbidity of the culture or in viable cell count. The synthesis of protein and nucleic acids began in uninfected cells immediately they were placed in the complete medium, turbidity increased from the start and the viable count after 30 min. This suggested that during lysogenization the infecting phage temporarily halts most if not all of the synthetic activities of the cell and thus forms an environment in which the phage genome can become attached to the bacterial chromosome and establish the pro-phage state.