A Plasmid-Based Fluorescence Reporter System for Monitoring Oxidative Damage in E. coli

Hariharan Dandapani, Pasi Kankaanpää, Patrik R Jones, Pauli Kallio

Research output: Contribution to journalArticleScientificpeer-review

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Quantitating intracellular oxidative damage caused by reactive oxygen species (ROS) is of interest in many fields of biological research. The current systems primarily rely on supplemented oxygen-sensitive substrates that penetrate the target cells, and react with ROS to produce signals that can be monitored with spectroscopic or imaging techniques. The objective here was to design a new non-invasive analytical strategy for measuring ROS-induced damage inside living cells by taking advantage of the native redox sensor system of E. coli. The developed plasmid-based sensor relies on an oxygen-sensitive transcriptional repressor IscR that controls the expression of a fluorescent marker in vivo. The system was shown to quantitatively respond to oxidative stress induced by supplemented H2O2 and lowered cultivation temperatures. Comparative analysis with fluorescence microscopy further demonstrated that the specificity of the reporter system was equivalent to the commercial chemical probe (CellROX). The strategy introduced here is not dependent on chemical probes, but instead uses a fluorescent expression system to detect enzyme-level oxidative damage in microbial cells. This provides a cheap and simple means for analysing enzyme-level oxidative damage in a biological context in E. coli.

Original languageEnglish
Article number6334
Number of pages15
Issue number17
Publication statusPublished - 23 Aug 2022
MoE publication typeA1 Journal article-refereed


  • Escherichia coli/genetics
  • Fluorescence
  • Hydrogen Peroxide/metabolism
  • Oxidative Stress/genetics
  • Oxygen/metabolism
  • Plasmids/genetics
  • Reactive Oxygen Species/chemistry


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