Characterization of infectious deoxyribonucleic acid from temperature Bacillus subtilis bacteriophage phi105.

Phenol-extracted, infectious deoxyribonucleic acid (DNA) species from phi105 phage particles, from phi105 lysogenic bacteria, and from induced phi105 lysogenic bacteria were sedimented in sucrose gradients. Infectious DNA from phi105 particles sedimented like the bulk of mature phage DNA in neutral sucrose. Infectivity of prophage DNA was associated with fast-sedimenting material of heterogenous size. Infectious vegetative phage DNA sedimented somewhat faster than mature phage DNA; it was rapidly converted to a poorly infectious form during the infection.