Effect of myxin on deoxyribonucleic acid synthesis in Escherichia coli infected with T4 bacteriophage.

Exposure of Escherichia coli cells to myxin results in the almost complete inhibition 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 of DNA 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 a significant fraction of the T4 DNA synthesized in the presence of myxin is apparently not properly enclosed by the bacteriophage protein coat since it is shown to be degraded by exogenous nuclease.