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ELECTROPHORETIC MOBILITIES OF ESCHERICHIA COLI 0157:H7 AND WILD-TYPE ESCHERICHIA COLI STRAINS
Lytle*, D A., E W. Rice*, C H. Johnson*, AND K R. Fox*. ELECTROPHORETIC MOBILITIES OF ESCHERICHIA COLI 0157:H7 AND WILD-TYPE ESCHERICHIA COLI STRAINS. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. American Society for Microbiology, Washington, DC, 65(7):3222-3225, (1999).
The electrophoretic mobility (EPM) of a number of human-virulent and "wild-type" Escherichia coli strains in phosphate buffered water was measured. The impact of pH, ionic strength, cation type (valence) and concentration, and bacterial strain on the EPM was investigated. Results showed that the electrophoretc mobility of virulent E. coli 0157:H7 strains greatly differed from wild-type strains. The EPM of wild-type strains were as much as 1.2 um cm V-1 s-1 greater in the direction of the cathode than 0157:H7 strains meaning wild-type strains had a more negative net surface charge. The suspension pH had a large impact on the EPM of both strains; as the pH decreased, the EPM also decreased. Increasing the ionic strength of the suspension by increasing the phosphate buffer concentration or adding salts largely impacted the EPM of wild-type E. coli strains and had little effect on the EPM of E. coli 0157:H7 strains. The EPM of wild-type strains decreased as the ionic strength of the suspension increased. The EPM was more strongly reduced as the valence state of the cation in the salt increased.