Evidence that Bacillus subtilis Bacteriophage SPO2 is Temperate and Heteroimmune to Bacteriophage φ105

Abstract

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 φ105 lysogens and phage φ105 plates on SPO2 lysogens; this indicates that SPO2 and φ105 are heteroimmune. Phage φ105 plates on an SPO2-resistant strain; this indicates that SPO2 and φ105 adsorb to different receptor sites on the bacterial surface.