Fig. 3.

Loss of recoverable pETBlue plasmid DNA from transformed NovaBlue cells following incubation with HOCl. Conditions: ~1×10⁸ E. coli/mL in 10 mL PBS incubated at 37 °C with the indicated amounts of HOCl for 4 h, after which a 10-fold excess of Na₂S₂O₃ was added to remove remaining oxidant, the plasmid was isolated, resuspended in H₂O, and run on 0.8% agarose as described in Experimental Procedures. Lane 1 shows purified pETBlue that had been digested with EcoR1, a restriction enzyme which catalyzes a single double-strand cut in the plasmid. Lane 7 contains the 1 kB DNA ladder. No DNA was recovered from cells exposed to HOCl at higher concentrations ([HOCl] = 250–1000 µM).