Inhibition of reproduction of the f2 bacteriophage by streptomycin

Streptomycin inhibits the propagation of the f₂, μ₂ and fd phages in streptomycin-resistant cells. Similarly the propagation of the phage in streptomycin-sensitive cells is inhibited under conditions when neither growth or protein synthesis are affected, i.e. at a concentration of 5μg/ml. and after a five-minute exposure. The average burst size is reduced by 60–80%. The latency period is prolonged and burst size also reduced in a single-step experiment. The inhibitory effect in the resistant host depends on the concentration of streptomycin, time of exposure and on the strain of the host bacterium. If streptomycin is present throughout the reproduction cycle the inhibitory effect is highest. At concentrations exceeding 200 μg./ml. streptomycin reduces the titre of phage lysates through precipitation of the phage particles. The inhibitory effect of streptomycin is blocked by sodium polymethacrylate, spermine, deoxyribo-nucleic acid and adenylic acid.