Evidence that Bacillus subtilis bacteriophage SP02 is temperate and heteroimmune to bacteriophage phi-105.

Some characteristics of Bacillus subtilis phage SPO2 which show that it is a temperate phage are presented. Wild-type SPO2 forms turbid plaques, similar to those of other temperate phages. SPO2 lysogenic strains which are resistant to SPO2 can be isolated; these strains remain stable lysogens despite the fact that they can no longer adsorb SPO2. SPO2 lysogenic strains can be grown for many generations in SPO2 antiserum and remain lysogenic. Phage SPO2 plates on phi105 lysogens and phage phi105 plates on SPO2 lysogens; this indicates that SPO2 and phi105 are heteroimmune. Phage phi105 plates on an SPO2-resistant strain; this indicates that SPO2 and phi105 adsorb to different receptor sites on the bacterial surface.