Characterization of Infectious Deoxyribonucleic Acid from Temperate Bacillus subtilis Bacteriophage φ 105

Abstract Phenol-extracted, infectious deoxyribonucleic acid (DNA) species from 105 phage particles, from 105 lysogenic bacteria, and from induced 105 lysogenic bacteria were sedimented in sucrose gradients. Infectious DNA from 105 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.