FIG. 3.

Southern blot hybridization analyses of DNAs from S. mitis strains B6 and HER and their phages. Chromosomal DNAs (left panel) prepared from the indicated strains were digested with HindIII and hybridized with a digoxigenin-labeled lytA gene. DNAs prepared from either M31 (ΔlytA) or the lysogenic strain 101 were used as controls. In the right panel, phage DNAs were digested with HindIII, blotted, and hybridized as above. The sizes (in kilobases) of the restriction fragments of HindIII-digested, biotinylated λ DNA (S) are indicated.