Isolation andProperties ofBacillus subtilis Strains Lysogenized byaClear Plaque Mutantof Bacteriophage 0105

A clear plaque mutantofthetemperate Bacillus phage4105lysogenized a smallfraction ofinfected cells forming an integrated prophage ator near the normal0105insertion site. Theselysogens exhibited a spontaneous induction rateapproximately 1,000-fold lower thanwildtypeandwerenoninducible (indj) bymitomycin C.Prophage was induced, however, whencompetent cultures were incubated withtransforming DNA.Theind-phenotype could notbeattributed solely totheclear plaque mutation andappearstoinvolve a cell-specific factor. Lysogenization bytheclear plaque mutant, incontrast towild-type phage, did notcausea markedreduction intransformation efficiency.