Action of 6-(p-hydroxyphenylazo)-uracil on bacteriophage IG 1.

IG 1, a temperate phage of Bacillus subtilis, is strongly induced from its lysogens by 6-(p-hydroxyphenylazo)-uracil, an azopyrimidine known as selectively inhibiting the B. subtilis DNA polymerase III. IG 1 phages originated either by induction or infection multiply, abundantly, in the presence of that azopyrimidine, in spite of the drastic decline of cell viability. Chloramphenicol completely suppresses the induction effect and also blocks the formation of spontaneously induced phage particles.