The effect of phage infection on the synthesis of lipid A by Escherichia coli

The synthesis and rate of incorporation of β-hydroxymyristic acid into bound lipids of Escherichia coli has been used to measure the effects of phage infection on lipid A synthesis. It was demonstrated that phage infection produces quantitative but not qualitative changes in the synthesis of the lipid A of hydrophobic lipopolysaccharides and the residual bound lipids. Lipid A synthesis continued at varying rates after infection, depending upon the phage used. The eventual block in lipid A synthesis in infected cells apparently is related to decreased respiration. This block was delayed if infecting phage could produce lysis inhibition, and very little inhibition was observed in cells infected with T4 mutants which cannot block respiration. Turnover studies indicated that lysis may degrade lipid A.