FIG. 2.

Southern analysis of genomic DNA from S. clavuligerus wild-type and pah mutant strains. Genomic DNA was digested with NcoI, separated by electrophoresis on agarose, blotted onto a nylon membrane, and probed with a pah-specific probe. The nylon membrane was exposed to X-ray film for 10 days at −70°C. Lane 1, S. clavuligerus wild type; lanes 2 and 3, thiostrepton-resistant isolates selected as potential pah mutants but shown to carry a wild-type pah gene (not pah mutants); lane 4, thiostrepton-resistant true pah mutant.