Inhibition of Phage Growth by an Antibiotic Rugulosin Isolated from Myrothecium verucaria

I. Properties of the Anti-Phage Effect

Abstract

It was found that (-)rugulosin, an antibiotic isolated from Myrothecium verucaria, had a potent anti-phage effect on RNA phages (MS2, GA and Qβ) and DNA phages (IA and T4). The effect was almost independent of the host bacterial strains used. By a detailed investigation using MS2, it was revealed that the antibiotic did not affect the free phage or host bacterium alone but inhibited phage multiplication, and the degree of the inhibition depended on the multiplicity of infection. The inhibition was not mainly due to a drop in the burst size but rather was due to a decrease of the phageproducing cells during the early stages of phage infection and replication.