Temperature shift-up leads to simultaneous and continuous plasmid DNA relaxation and induction of DnaK and GroEL proteins in anaerobically growing Escherichia coli cells

Tohru Mizushima, Yoshihisa Ohtsuka, Takeyoshi Miki, Kazuhisa Sekimizu

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We previously reported that plasmid DNA in Escherichia coli cells growing under aerobic conditions relaxed immediately and transiently after heat shock (Mizushima, T., Natori, S. and Sekimizu, K., Mol. Gen. Genet. (1993) 238, 1-5). We next examined DNA relaxation and induction of heat shock proteins after heat shock in cells growing under anaerobic conditions. DNA in these cells relaxed rapidly (2 min) after heat shock (42°C), as was the case with aerobically growing cells, but full superhelicity was not recovered. The relaxed state of DNA topology was maintained for 60 min after heat shock. Induction of DnaK and GroEL proteins, which was transient in aerobically growing cells, was continuous in anaerobically growing cells. Therefore, induction of heat shock proteins correlated with DNA relaxation in both aerobic and anaerobic conditions.

Original languageEnglish
Pages (from-to)333-336
Number of pages4
JournalFEMS microbiology letters
Issue number3
Publication statusPublished - 1994 Sep 1



  • Anaerobic growth
  • DNA relaxation
  • Escherichia coli
  • Heat shock protein

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics

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