Mixed bacteriophage infection of Escherichia coli : exclusion of superinfecting T4 by T7

E. coli was infected with T7 as primary infector and T4 as secondary infector. When the time between primary and secondary infection was 5 minutes or more, most of the resulting plaques were T7. Varying multiplicity of T4 and T7 from 3 to 9 did not affect exclusion efficiency. Genomes of excluded T4 phages were injected but did not replicate or break down extensively. No T4 proteins were detected in superinfection exclusion. RNA synthesis upon injected T4 genomes was partially inhibited. T7 0.7amJS62a as primary infector gave a reduced efficiency of exclusion. T7 laml93 as primary infector abolished exclusion.Science, Faculty ofMicrobiology and Immunology, Department ofGraduat