FIG. 1.

Southern hybridization of restricted DNAs from M1inv+ and M1inv− clinical isolates to dioxigenin-labelled phage DNAs. Strain T253c has been cured of phage T12 and other plaque-forming phages. (A) HaeIII-digested DNAs were probed with digoxigenin-labelled phage T12 DNA. Strains 87-263, 87-442, and L462 are M1inv− isolates. The remaining strains are M1inv+. The asterisk marks an speA HaeIII fragment. (B) ClaI-digested DNAs from M1inv+ clinical isolates were probed with labelled phage T13 DNA. Strain T253c(T13) is a T13 lysogen that was purified from a single plaque. (C) ClaI-digested DNA from M1inv− strains probed with labelled phage T13 DNA. DNA from the M1inv+ strain 90-226 was included as a positive control. Strain 85-069 was designated M1inv− on the basis of RFLP (data not shown) and because it lacks phage T14.