Propidium ion enters viable cells with high membrane potential during live-dead staining
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High-throughput Measurement of Plasma Membrane Resealing Efficiency in Mammalian Cells
Published on: January 7, 2019
Christian Kirchhoff1, Heribert Cypionka1
1Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University of Oldenburg, Oldenburg, Germany.
Abstract:
Live-dead staining with propidium iodide can give erroneous results for bacteria showing high membrane potentials. We observed uptake of propidium ions across intact cell membranes for Dinoroseobacter shibae and Bacillus subtilis. Apparently, a high membrane potential facilitates breakthrough of the double-charged propidium ion and can mark viable cells as dead.
Insights
Propidium iodide live-dead staining can be inaccurate for bacteria with high membrane potentials. High membrane potential in bacteria like Dinoroseobacter shibae can incorrectly label viable cells as dead.
Area of Science:
- Microbiology
- Cell Biology
- Bacteriology
Background:
- Live-dead staining is crucial for assessing bacterial viability.
- Propidium iodide (PI) is a common DNA-intercalating dye used for this purpose.
- Bacterial membrane potential is a key factor in cell viability and function.
Purpose of the Study:
- To investigate the impact of high membrane potential on the accuracy of propidium iodide live-dead staining in bacteria.
- To determine if propidium iodide can penetrate intact bacterial cell membranes under specific conditions.
Main Methods:
- Bacterial strains Dinoroseobacter shibae and Bacillus subtilis were used.
- Live-dead staining was performed using propidium iodide.
- Microscopic observation was employed to assess dye uptake and cell integrity.
Main Results:
- Propidium iodide uptake was observed across intact cell membranes in both Dinoroseobacter shibae and Bacillus subtilis.
- Bacteria exhibiting high membrane potentials showed erroneous live-dead staining results.
- Viable cells with high membrane potentials were incorrectly identified as dead.
Conclusions:
- High membrane potential in bacteria can lead to false-positive dead cell counts with propidium iodide staining.
- The integrity of the bacterial cell membrane is not always sufficient to exclude propidium iodide when membrane potential is high.
- This finding highlights a critical limitation of propidium iodide staining in certain bacterial species or conditions.
