Transient relaxation of plasmid DNA in Escherichia coli by fluoroquinolones

Miki Matsuo, Yoshihisa Ohtsuka, Kazuhiro Kataoka, Tohru Mizushima, Kazuhisa Sekimizu

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We examined the influence of fluoroquinolones (norfloxacin, enoxacin, ofloxacin, levofloxacin, and sparfloxacin) on DNA supercoiling of plasmids in Escherichia coli cells by analysis with agarose gel electrophoresis in the presence of chloroquine. All the fluoroquinolones tested immediately induced DNA relaxation. The relaxed DNA was re-supercoiled, and the process was sensitive to chloramphenicol, suggesting that newly synthesized proteins participate in the reaction. The concentrations of fluoroquinolones required for DNA relaxation were much higher than those required for cell killing. The bactericidal effect of fluoroquinolones is apparently related to mechanisms other than DNA relaxation.

Original languageEnglish
Pages (from-to)985-987
Number of pages3
JournalJournal of Pharmacy and Pharmacology
Issue number9
Publication statusPublished - 1996 Sept
Externally publishedYes

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science


Dive into the research topics of 'Transient relaxation of plasmid DNA in Escherichia coli by fluoroquinolones'. Together they form a unique fingerprint.

Cite this