FIG. 3.

(A) Southern hybridization studies of the single- and double-stranded products produced by asymmetric PCR of the insert from pPSC-3. Row a contains the products of asymmetric PCR with the T7 primer in 50-fold molar excess; row b contains the products of asymmetric PCR with the SP6 primer in 50-fold molar excess. The probe used in panel 1 was the T7 primer, the probe used in panel 2 was the SP6 primer, and the probe used in panel 3 was generated from pyocin ssDNA by random primer extension. (B) Composite showing the results of dot hybridization of a set of complementary probes which were derived from the sequence of a region of pPSC-3 (lane 1, PSC-3 OLIGO 1, lane 2, PSC-3 OLIGO 2) and a probe generated to pyocin DNA by random primer extension (lane 3) of the insert from pPSC-3 (row a) and pyocin DNA (row b). This figure demonstrates that only one of the two complementary primers hybridized to the pyocin DNA, providing further proof that this DNA is single stranded.