Reversible and irreversible pollutant-induced bacterial cellular stress effects measured by ethidium bromide uptake and efflux.

Détails

ID Serval
serval:BIB_A2708E1774B4
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Reversible and irreversible pollutant-induced bacterial cellular stress effects measured by ethidium bromide uptake and efflux.
Périodique
Environmental Science and Technology
Auteur(s)
Czechowska K., van der Meer J.R.
ISSN
1520-5851 (Electronic)
ISSN-L
0013-936X
Statut éditorial
Publié
Date de publication
2012
Volume
46
Numéro
2
Pages
1201-1208
Langue
anglais
Résumé
Chemical pollution is known to affect microbial community composition but it is poorly understood how toxic compounds influence physiology of single cells that may lay at the basis of loss of reproductive fitness. Here we analyze physiological disturbances of a variety of chemical pollutants at single cell level using the bacterium Pseudomonas fluorescens in an oligotrophic growth assay. As a proxy for physiological disturbance we measured changes in geometric mean ethidium bromide (EB) fluorescence intensities in subpopulations of live and dividing cells exposed or not exposed to different dosages of tetradecane, 4-chlorophenol, 2-chlorobiphenyl, naphthalene, benzene, mercury chloride, or water-dissolved oil fractions. Because ethidium bromide efflux is an energy-dependent process any disturbance in cellular energy generation is visible as an increased cytoplasmic fluorescence. Interestingly, all pollutants even at the lowest dosage of 1 nmol/mL culture produced significantly increased ethidium bromide fluorescence compared to nonexposed controls. Ethidium bromide fluorescence intensities increased upon pollutant exposure dosage up to a saturation level, and were weakly (r(2) = 0.3905) inversely correlated to the proportion of live cells at that time point in culture. Temporal increase in EB fluorescence of growing cells is indicative for toxic but reversible effects. Cells displaying high continued EB fluorescence levels experience constant and permanent damage, and no longer contribute to population growth. The procedure developed here using bacterial ethidium bromide efflux pump activity may be a useful complement to screen sublethal toxicity effects of chemicals.
Mots-clé
Cell Membrane/drug effects, Cell Membrane/physiology, Environmental Pollutants/toxicity, Ethidium/metabolism, Hazardous Substances/toxicity, Pseudomonas fluorescens/cytology, Pseudomonas fluorescens/drug effects, Stress, Physiological/drug effects
Pubmed
Web of science
Création de la notice
19/12/2012 9:30
Dernière modification de la notice
20/08/2019 15:08
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