These authors contributed equally to this work.
Limits of propidium iodide as a cell viability indicator for environmental bacteria†
Article first published online: 9 APR 2007
Copyright © 2007 International Society for Analytical Cytology
Cytometry Part A
Volume 71A, Issue 8, pages 592–598, August 2007
How to Cite
Shi, L., Günther, S., Hübschmann, T., Wick, L. Y., Harms, H. and Müller, S. (2007), Limits of propidium iodide as a cell viability indicator for environmental bacteria. Cytometry, 71A: 592–598. doi: 10.1002/cyto.a.20402
Part of this manuscript was presented at the 11th Leipziger Workshop, April 27–29, 2006, BioCity Leipzig, Germany. Available at www.leipziger-workshop.de.
- Issue published online: 18 JUL 2007
- Article first published online: 9 APR 2007
- Manuscript Accepted: 15 NOV 2006
- Manuscript Revised: 12 NOV 2006
- Manuscript Received: 25 JUL 2006
- multiparametric flow cytometry;
- bacterial viability;
- population dynamics;
- live/dead staining;
- propidium iodide
Viability measurements of individual bacteria are applied in various scopes of research and industry using approaches where propidium iodide (PI) serves as dead cell indicator. The reliability of PI uptake as a cell viability indicator for dead (PI permeable) and viable (PI impermeable) bacteria was tested using two soil bacteria, the gram−Sphingomonas sp. LB126 and the gram+Mycobacterium frederiksbergense LB501T.
Bacterial proliferation activities observed viaDAPI and Hoechst 33342 staining were linked to the energy charge and the proportion of dead cells as obtained by diOC6 (3)-staining and PI-uptake, respectively. Calibration and verification experiments were performed using batch cultures grown on different substrates.
PI uptake depended on the physiological state of the bacterial cells. Unexpectedly, up to 40% of both strains were stained by PI during early exponential growth on glucose when compared to 2–5% of cells in the early stationary phase of growth.
The results question the utility of PI as a universal indicator for the viability of (environmental) bacteria. It rather appears that in addition to nonviable cells, PI also stains growing cells of Sphingomonas sp. and M. frederiksbergense during a short period of their life cycle. © 2007 International Society for Analytical Cytology