FIG. 1.
Inhibition of T4 replication by m-AMSA. Nonsuppressing E. coli cells were infected with either bacteriophage K10 (encoding wild-type topoisomerase) (A) or K10-39am (topoisomerase-deficient mutant) (B). Phage attachment was allowed for 4 min, and m-AMSA was added 2 min later (at 0, 5, 15, and 50 μg/ml in lanes 1 to 4, respectively). After an additional 18 min of infection, DNA was harvested. The DNA was purified, digested with AseI and HaeIII, and subjected to electrophoresis through a 1% agarose gel, and the resulting fragments were visualized by ethidium bromide staining. These bacterial cells also harbored a plasmid containing a T4 origin; plasmid replication is analyzed in detail below (Fig. 2).