Open AccessMembrane hyperpolarisation by valinomycin and its limitations for bacterial viability assessment using rhodamine 123 and flow cytometry
Author(s) -
Porter J,
Pickup R,
Edwards C
Publication year - 1995
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1995.tb07843.x
Subject(s) - valinomycin , rhodamine 123 , enterobacter aerogenes , ionophore , nigericin , membrane potential , pseudomonas fluorescens , flow cytometry , chemistry , viability assay , rhodamine b , membrane , rhodamine , biophysics , chromatography , biochemistry , escherichia coli , microbiology and biotechnology , biology , bacteria , cell , fluorescence , physics , photocatalysis , quantum mechanics , multiple drug resistance , catalysis , gene , antibiotics , genetics
The ionophore, valinomycin, was investigated as a possible means of bacterial viability assessment using the fluorescent membrane potential dye rhodamine 123. Membrane hyperpolarisation in Escherichia coli , Pseudomonas fluorescent , Enterobacter aerogenes and Arthrobacter globiformis was examined during exponential growth and during stress by brief starvation in a high sodium, low potassium buffer using flow cytometric analysis of rhodamine 123 uptake. Dye uptake was variable both between species and amongst cells from the same culture. Exponential phase cells showed no increase in dye uptake due to valinomycin treatment. Stressed P. fluorescens cells responded to valinomycin treatment by increased dye uptake, while stressed E. coli and A. globiformis cells showed no response. Approximately 50% of stressed Eb. aerogenes cells responded to valinomycin. The results demonstrate the limitations of rhodamine dye for viability analysing the viability of diverse bacterial communities and underline the degree of cell heterogeneity in batch cultures.