Deoxyribonucleic Acid Synthesis

Exposure of Escherichia coli cells to myxin results in the almost complete in'hibition of new deoxyribonucleic acid (DNA) synthesis, extensive degradation of pre-existing intracellular DNA, and a rapid loss of viability in these cells (9). After exposure to myxin for 30 min (<1% survivors and >25% degradation of DNA), infection of these cells by T4 bacteriophage results in the renewal of DNA synthesis at a rate essentially equal to that found in T4-infected cells in the absence of myxin. This DNA was characterized as T4 DNA by hybridization and by hydroxyapatite chromatography. These results suggest that the primary site of action of myxin does not involve the biochemical pathways involved in either the energy metabolism or the biosynthesis ofDNA precursors in the uninfected host cell. The yield of infectious T4 particles was reduced when myxin was present during multiplication. This effect may be partly accounted for by the finding that