Previous Article | Next Article 
Applied and Environmental Microbiology, May 2005, p. 2501-2510, Vol. 71, No. 5
0099-2240/05/$08.00+0 doi:10.1128/AEM.71.5.2501-2510.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
Application of a pH-Sensitive Fluoroprobe (C-SNARF-4) for pH Microenvironment Analysis in Pseudomonas aeruginosa Biofilms
Ryan C. Hunter* and
Terry J. Beveridge
Department of Microbiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
Received 24 September 2004/
Accepted 26 November 2004
An important feature of microbial biofilms is the development of four-dimensional physical and chemical gradients in space and time. There is need for novel approaches to probe these so-called microenvironments to determine their effect on biofilm-specific processes. In this study, we describe the use of seminaphthorhodafluor-4F 5-(and-6) carboxylic acid (C-SNARF-4) for pH microenvironment analysis in Pseudomonas aeruginosa biofilms. C-SNARF-4 is a fluorescent ratiometric probe that allows pH quantification independent of probe concentration and/or laser intensity. By confocal scanning laser microscopy, C-SNARF-4 revealed pH heterogeneity throughout the biofilm in both the x,y and x,z planes, with values ranging from pH 5.6 (within the biofilm) to pH 7.0 (bulk fluid). pH values were typically remarkably different than those just a few micrometers away. Although this probe has been successfully used in a number of eukaryotic systems, problems have been reported which describe spectral emission changes as a result of macromolecular interactions with the fluorophore. To assess how the biofilm environment may influence fluorescent properties of the dye, fluorescence of C-SNARF-4 was quantified via spectrofluorometry while the probe was suspended in various concentrations of representative biofilm matrix components (i.e., proteins, polysaccharides, and bacterial cells) and growth medium. Surprisingly, our data demonstrate that few changes in emission spectra occur as a result of matrix interactions below pH 7. These studies suggest that C-SNARF-4 can be used as a reliable indicator of pH microenvironments, which may help elucidate their influence on the medical and geobiological roles of natural biofilms.
* Corresponding author. Mailing address: Department of Microbiology, CBS, University of Guelph, Guelph, Ontario N1G 2W1, Canada. Phone: (519) 824-4120, ext. 58904. Fax: (519) 837-8702. E-mail:
rhunte01{at}uoguelph.ca.
Applied and Environmental Microbiology, May 2005, p. 2501-2510, Vol. 71, No. 5
0099-2240/05/$08.00+0 doi:10.1128/AEM.71.5.2501-2510.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Tseng, I-C., Xu, H., Chou, F.-P., Li, G., Vazzano, A. P., Kao, J. P. Y., Johnson, M. D., Lin, C.-Y.
(2010). Matriptase Activation, an Early Cellular Response to Acidosis. J. Biol. Chem.
285: 3261-3270
[Abstract]
[Full Text]
-
Hidalgo, G., Burns, A., Herz, E., Hay, A. G., Houston, P. L., Wiesner, U., Lion, L. W.
(2009). Functional Tomographic Fluorescence Imaging of pH Microenvironments in Microbial Biofilms by Use of Silica Nanoparticle Sensors. Appl. Environ. Microbiol.
75: 7426-7435
[Abstract]
[Full Text]
-
Venn, A. A., Tambutte, E., Lotto, S., Zoccola, D., Allemand, D., Tambutte, S.
(2009). From the Cover: Imaging intracellular pH in a reef coral and symbiotic anemone. Proc. Natl. Acad. Sci. USA
106: 16574-16579
[Abstract]
[Full Text]
-
Wu, J., Xu, H., Tang, W., Kopelman, R., Philbert, M. A., Xi, C.
(2009). Eradication of Bacteria in Suspension and Biofilms Using Methylene Blue-Loaded Dynamic Nanoplatforms. Antimicrob. Agents Chemother.
53: 3042-3048
[Abstract]
[Full Text]
-
Schooling, S. R., Hubley, A., Beveridge, T. J.
(2009). Interactions of DNA with Biofilm-Derived Membrane Vesicles. J. Bacteriol.
191: 4097-4102
[Abstract]
[Full Text]
-
Palmer, R. J. Jr., Stoodley, P.
(2007). Biofilms 2007: Broadened Horizons and New Emphases. J. Bacteriol.
189: 7948-7960
[Full Text]
-
Sandoz, K. M., Mitzimberg, S. M., Schuster, M.
(2007). From the Cover: Social cheating in Pseudomonas aeruginosa quorum sensing. Proc. Natl. Acad. Sci. USA
104: 15876-15881
[Abstract]
[Full Text]
-
Villain-Guillot, P., Gualtieri, M., Bastide, L., Leonetti, J.-P.
(2007). In Vitro Activities of Different Inhibitors of Bacterial Transcription against Staphylococcus epidermidis Biofilm. Antimicrob. Agents Chemother.
51: 3117-3121
[Abstract]
[Full Text]
-
Webster, P., Wu, S., Gomez, G., Apicella, M., Plaut, A. G., St. Geme, J. W. III
(2006). Distribution of Bacterial Proteins in Biofilms Formed by Non-typeable Haemophilus influenzae. J. Histochem. Cytochem.
54: 829-842
[Abstract]
[Full Text]