Skip to main content
. Author manuscript; available in PMC: 2005 Sep 13.
Published in final edited form as: Mol Microbiol. 2005 Jun;56(6):1416–1429. doi: 10.1111/j.1365-2958.2005.04638.x

Fig. 1.

Fig. 1

Norfloxacin treatment causes cleavage complex formation at gyrase binding sites. Cells containing pBR322 (lanes 1–10) or pBR322MUT990 (lane 11) were lysed under cleavage (C) or resealing (R) conditions; DNA was extracted and dialysed overnight into TE buffer and then digested with EcoRI. Samples were loaded onto a 1.2% agarose gel, which was analysed by Southern hybridization using a pBR322 probe.

A. JH39 (lanes 1–3), parCR (lanes 4–6), or gyrAR (lanes 7–9) cells were treated with norfloxacin (NOR) for 6 min (lanes 2–3, lanes 5–6, lanes 8–9) or were untreated (lanes 1, 4 and 7). The marker lane consisted of a mixture of restriction fragments derived from plasmids pBR322 and pSF5 (a pBR322 derivative with an approximately 13-kb fragment of phage lambda DNA; obtained from Dr M. Feiss, University of Iowa).

B. JH39 cells carrying pBR322 (lane 10) or pBR322MUT990 (lane 11) were treated with norfloxacin and DNA was extracted under cleavage lysis conditions. Arrows indicate cleavage complex bands resulting from cleavage at the major gyrase binding site centred at 990 bp. The marker lane consisted of a mixture of restriction fragments of pBR322.