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Updated: May 25, 2026
Kinetic Visualization of Single-Cell Interspecies Bacterial Interactions
Published on: August 5, 2020
ROS-mediated killing efficiency with visible light of bacteria carrying different red fluorochrome proteins
Waldemar Waldeck1, Elena Heidenreich, Gabriele Mueller
1German Cancer Research Center, Division of Biophysics of Macromolecules, INF 580, D-69120 Heidelberg, Germany.
Abstract:
Red fluorescent proteins can generate reactive oxygen species (ROS) if their fluorochrome is stimulated e.g. by visible light illumination. ROS compounds have very reactive, highly toxic properties leading to cell damage which results in cell killing. In this context, the toxicity of the various red fluorochromes KillerRed, DsRed2, mCherry, and mRFP expressed in Escherichia coli bacteria was tested after illumination with white light. The toxic effect was determined by measurement of the colony forming ability 24h after transfection and illumination. KillerRed was found to be the most harmful, followed by mRFP and DsRed2 while bacteria expressing mCherry and controls without fluorescent proteins survived after application of identical illumination doses. Their application and a possible bactericide role is discussed.
Insights
Red fluorescent proteins can generate toxic reactive oxygen species (ROS) when illuminated. KillerRed protein exhibited the highest toxicity in Escherichia coli bacteria, suggesting potential bactericide applications.
Area of Science:
- Biochemistry
- Microbiology
- Cell Biology
Background:
- Red fluorescent proteins (RFPs) can produce reactive oxygen species (ROS) upon light stimulation.
- ROS are highly reactive and toxic compounds capable of causing significant cellular damage and death.
- Understanding RFP-induced ROS generation is crucial for applications involving light exposure.
Purpose of the Study:
- To evaluate and compare the toxicity of different red fluorescent proteins (KillerRed, DsRed2, mCherry, mRFP) in Escherichia coli.
- To assess the impact of white light illumination on RFP-induced cellular damage.
- To explore the potential bactericidal role of specific RFPs.
Main Methods:
- Expression of various red fluorescent proteins (KillerRed, DsRed2, mCherry, mRFP) in Escherichia coli.
- Exposure of transfected bacteria to white light illumination.
- Quantification of bacterial toxicity by measuring colony-forming ability 24 hours post-illumination.
Main Results:
- KillerRed demonstrated the highest toxicity, significantly reducing bacterial viability.
- mRFP and DsRed2 also exhibited toxicity, though to a lesser extent than KillerRed.
- Bacteria expressing mCherry and control groups without fluorescent proteins showed survival after illumination.
Conclusions:
- The choice of red fluorescent protein significantly impacts cellular toxicity upon light exposure.
- KillerRed poses the greatest risk due to its potent ROS generation.
- These findings suggest potential applications for specific RFPs as bactericidal agents.
