Figure 2.

The 3′ end of the oriT-specific reaction product maps to the same nucleotide position in plasmids R1 and F. In two separate experiments, 100, 200, 400, and 800 μl of mating cultures containing either J5[R1-19] (lanes 1–4, respectively); 50, 100, 200, and 400 μl of J5[pOX38-Km] (lanes 5–8, respectively); or 400 μl of J5 without plasmid (lane 9) were centrifuged and the cell pellets treated as described. Autoradiograms of the gels are shown. Arrow indicates reaction products terminated specifically at nic. Correcting for culture density, comparable numbers of cells of both strains were present in the reaction mixtures.