Abstract
A well-characterized experimental system was designed to evaluate the effect of porous media on macroscopic transport coefficients which are used to characterize the migration of bacterial populations. Bacterial density profiles of Pseudomonas putida PRS2000 were determined in the presence and absence of a chemical attractant (3-chlorobenzoate) gradient within sand columns having a narrow distribution of particle diameters. These experimental profiles were compared with theoretical predictions to evaluate the macroscopic transport coefficients. The effective random motility coefficient, used to quantify migration due to a random process in a porous medium, decreased nearly 20-fold as grain size in the columns decreased from 800 to 80 (mu)m. The effective random motility coefficient (mu)(infeff) was related to the random motility coefficient (mu), measured in a bulk aqueous system, according to (mu)(infeff) = ((epsilon)/(tau))(mu) with porosity (epsilon) and tortuosity (tau). Over the times and distances examined in these experiments, bacterial density profiles were unaffected by the presence of an attractant gradient. Theoretical profiles with the aqueous phase value of the chemotactic sensitivity coefficient (used to quantify migration due to a directed process) were consistent with this result and suggested that any chemotactic effect on bacterial migration was below the detection limits of our assay.
Full Text
The Full Text of this article is available as a PDF (264.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- COHEN-BAZIRE G., SISTROM W. R., STANIER R. Y. Kinetic studies of pigment synthesis by non-sulfur purple bacteria. J Cell Physiol. 1957 Feb;49(1):25–68. doi: 10.1002/jcp.1030490104. [DOI] [PubMed] [Google Scholar]
- Duffy K. J., Cummings P. T., Ford R. M. Random walk calculations for bacterial migration in porous media. Biophys J. 1995 Mar;68(3):800–806. doi: 10.1016/S0006-3495(95)80256-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harwood C. S. A methyl-accepting protein is involved in benzoate taxis in Pseudomonas putida. J Bacteriol. 1989 Sep;171(9):4603–4608. doi: 10.1128/jb.171.9.4603-4608.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harwood C. S., Fosnaugh K., Dispensa M. Flagellation of Pseudomonas putida and analysis of its motile behavior. J Bacteriol. 1989 Jul;171(7):4063–4066. doi: 10.1128/jb.171.7.4063-4066.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harwood C. S., Nichols N. N., Kim M. K., Ditty J. L., Parales R. E. Identification of the pcaRKF gene cluster from Pseudomonas putida: involvement in chemotaxis, biodegradation, and transport of 4-hydroxybenzoate. J Bacteriol. 1994 Nov;176(21):6479–6488. doi: 10.1128/jb.176.21.6479-6488.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harwood C. S., Parales R. E., Dispensa M. Chemotaxis of Pseudomonas putida toward chlorinated benzoates. Appl Environ Microbiol. 1990 May;56(5):1501–1503. doi: 10.1128/aem.56.5.1501-1503.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harwood C. S., Rivelli M., Ornston L. N. Aromatic acids are chemoattractants for Pseudomonas putida. J Bacteriol. 1984 Nov;160(2):622–628. doi: 10.1128/jb.160.2.622-628.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Keller E. F., Segel L. A. Model for chemotaxis. J Theor Biol. 1971 Feb;30(2):225–234. doi: 10.1016/0022-5193(71)90050-6. [DOI] [PubMed] [Google Scholar]
- Macnab R. M., Aizawa S. Bacterial motility and the bacterial flagellar motor. Annu Rev Biophys Bioeng. 1984;13:51–83. doi: 10.1146/annurev.bb.13.060184.000411. [DOI] [PubMed] [Google Scholar]
- Ordal G. W. Bacterial chemotaxis: biochemistry of behavior in a single cell. Crit Rev Microbiol. 1985;12(2):95–130. doi: 10.3109/10408418509104426. [DOI] [PubMed] [Google Scholar]
- Reynolds P. J., Sharma P., Jenneman G. E., McInerney M. J. Mechanisms of microbial movement in subsurface materials. Appl Environ Microbiol. 1989 Sep;55(9):2280–2286. doi: 10.1128/aem.55.9.2280-2286.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sharma P. K., McInerney M. J. Effect of grain size on bacterial penetration, reproduction, and metabolic activity in porous glass bead chambers. Appl Environ Microbiol. 1994 May;60(5):1481–1486. doi: 10.1128/aem.60.5.1481-1486.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sharma P. K., McInerney M. J., Knapp R. M. In situ growth and activity and modes of penetration of Escherichia coli in unconsolidated porous materials. Appl Environ Microbiol. 1993 Nov;59(11):3686–3694. doi: 10.1128/aem.59.11.3686-3694.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]