Characterization of Bacteriophage SPPl Transducing Particles

~~ ~~ Bacillus subtilis lysates produced by virulent bacteriophage SPPl retained their transducing ability upon purification from contaminating PBSX particles. The buoyant density in CsCl of the transducing activity was indistinguishable from that of the SPPl plaque-forming units and the sedimentation behaviour in sucrose gradients of purified transducing particles was the same as that of SPPl phage particles. Further, high concentrations of anti-SPPl serum inactivated transducing particles and SPPl plaque-forming units at the same rate. The transduction process was resistant to DNAase treatment, but was enhanced by temperatures that did not allow transformation. It was concluded that particles of the size, shape, density and serum-sensitivity characteristic of SPPl , but carrying bacterial DNA, are vectors in a true transduction process. Cell survival upon SPPl infection is discussed.