Gene expression of Escherichia coli in continuous culture during adaptation to artificial sunlight

Michael Berney, Hans Ulrich Weilenmann, Thomas Egli

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Escherichia coli growing in continuous culture under continuous UVA irradiation exhibits growth inhibition with a subsequent adaptation to the stress. Transcriptome analysis was performed during transient growth inhibition and in the UVA light-adapted growth state. The results indicate that UVA light induces stringent response and an additional response that includes the upregulation of the synthesis of valine, isoleucine, leucine, phenylalanine, histidine and glutamate. The induction of several SOS response-genes strongly points to DNA damage as a result of UVA exposure. The involvement of oxidative stress was observed with the induction of ahpCF. Taken together it supports the hypothesis of the production of reactive oxygen species by UVA light. In the UVA-adapted cell population strong repression of the acid tolerance response was found. We identified the enzyme chorismate mutase as a possible chromophore for UVA light-inactivation and found strong repression of the pyrBI operon and the gene mgtA encoding for an ATP-dependent Mg2+ transporter. Furthermore, our results indicate that the role of RpoS may not be as important in the adaptation of E. coli to UVA light as it was implicated by previous results with starved cells, but that RpoS might be of crucial importance for the resistance under transient light exposure.

Original languageEnglish (US)
Pages (from-to)1635-1647
Number of pages13
JournalEnvironmental Microbiology
Issue number9
StatePublished - Sep 1 2006
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics


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