Journal article
Surface Characteristics and Adhesion Behavior of Escherichia coli O157:H7: Role of Extracellular Macromolecules
Biomacromolecules, v 10(9), pp 2556-2564
14 Sep 2009
PMID: 19746994
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Experiments were conducted using enterohemorrhagic Escherichia coli O157:117 cells to investigate the influence of extracellular macromolecules on cell surface properties and adhesion behavior to quartz sand. Partial removal of the extracellular macromolecules on cells by a proteolytic enzyme (proteinase K) was confirmed using Fourier transform infrared spectroscopy analyses. The proteinase K treated cells exhibited more negative electrophoretic mobility (EPM) at an ionic strength (IS) <= 1 mM, a slightly lower isoelectric point, and were less hydrophobic as compared to the untreated cells. Potentiometric titration results indicated that the total site concentration (i.e., the total amount: of exposed functional groups per cell) on the treated cells was approximately 22% smaller than the untreated cells, while the dissociation constants were almost identical. Analysis of the EPM data using soft particle theory showed that the removal of extracellular macromolecules resulted in polymeric layers outside the cell surface that were less electrophoretically soft. The more negative mobility for the treated cells was likely due to the combined effects of a change in the distribution of functional groups and an increase in the charges per unit volume after enzyme treatment and not just removal of extracellular macromolecules. The proteolytic digestion of extracellular macromolecules led to a significant difference in the cell adhesion to quartz sand. The adhesion behavior for treated cells was consistent with DLVO theory and increased with IS due to less negativity in the EPM. In contrast, the adhesion behavior of untreated cells was much more complex and exhibited a maximum at IS = 1 mM. The treated cells exhibited less adhesion than the untreated cells when the IS <= 1 mM due to their more negative EPM. However, when the IS >= 10 mM, a sudden decrease in the removal efficiency was observed only for the untreated cells even through EPM values were similar for both treated and untreated cells. This result suggested that an additional non-DLVO type interaction, electrosteric repulsion, occurred at higher IS (>= 10 mM in this study) for the untreated cells due to the presence of extracellular macromolecules that hindered cell adhesion to the quartz surface, This finding provides important insight into the role of macromolecule-induced E. coli O157:H7 interactions in aquatic environments.
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Details
- Title
- Surface Characteristics and Adhesion Behavior of Escherichia coli O157:H7: Role of Extracellular Macromolecules
- Creators
- Hyunjung N. Kim - Univ Calif Riverside, Dept Chem & Environm Engn, Riverside, CA 92521 USAYongsuk Hong - University of California, RiversideIlkeun Lee - U.S. Salinity LaboratoryScott A. Bradford - U.S. Salinity LaboratorySharon L. Walker - U.S. Salinity Laboratory
- Publication Details
- Biomacromolecules, v 10(9), pp 2556-2564
- Publisher
- American Chemical Society; Washington, DC
- Number of pages
- 9
- Grant note
- 2006-02541 / USDA CSREES NRI; United States Department of Agriculture (USDA); National Institute of Food and Agriculture
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- College of Engineering
- Web of Science ID
- WOS:000269671200021
- Scopus ID
- 2-s2.0-70349282132
- Other Identifier
- 991021229897304721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Biochemistry & Molecular Biology
- Chemistry, Organic
- Polymer Science