MECHANISMS OF NONPERMISSIVENESS IN ABORTIVE INFECTION OF BACTERIOPHAGE φNR2 IN BACILLUS SUBTILIS MARBURG STRAIN

Abstract

A mutant strain PS9, permissive to infection of phages SP10 and φNR2, was derived from a nonpermissive Marburg strain of Bacillus subtilis. When treated with mitomycin C or ultraviolet irradiation, PS9 cells lysed to produce defective phage PBSX as did the nonpermissive cells. Thus it was suggested that the nonpermissiveness might be independent of the repression system of the defective phage PBSX. As another approach to elucidate the mechanism of nonpermissiveness, DNA and RNA syntheses were analyzed in both permissive and nonpermissive cells infected with phage φNR2. By molecular hybridization with phage DNA, it was found that, in the nonpermissive cells, φNR2 DNA did not replicate but phage-directed RNA was partially synthesized. The RNA synthesized in the nonpermissive B. subtilis Marburg appeared to lack late messenger RNA compared to RNA synthesized in the permissive cells.