FIG. 3.

Analysis of piperidine-sensitive sites in plasmid pUB110 from EMS-treated wild-type and α⁻β⁻ spores. Spores of strain PS533 (wild type) (A) and PS578 (α⁻β⁻) (B) were incubated at 30°C in 0.4 M KPO₄ (pH 7) with (lanes 1, 2, 3, and 4) or without (lane 5) 0.45 M EMS. Spore DNA was isolated, treated with piperidine, denatured with glyoxal, and electrophoresed on agarose gels; the DNA was transferred to Hybond N membranes; and pUB110 sequences were detected as described in the text. Lanes: 1, 2, 3, and 4, incubated with EMS for 20 min, 90 min, 6 h, and 12 h, respectively; 5, incubated without EMS for 12 h. The positions of size markers of 3.5 and 1 kb are shown on the left. The two bands in the doublet seen at the top of the gel are circular pUB110 (upper band) and linear pUB110 (4.5 kb).