The Alkaline Isopotential Point of the Bacterial Cell

Irregularities in migration velocity of bacterial cells in the highly alkaline solutions are due to the buffering effect of the cells upon the immediately adjacent zone of menstruum. Consistent results can be obtained by shaking the suspension thoroughly before placing it in the electrophoretic cell. When observed in this way both Bacillus cereus and Bacterium coli show an isopotential point near pH 13.5, that for Bacillus cereus being slightly below, and that for Bacterium coli slightly above this point. At more alkaline reactions the cells acquire a positive charge which increases with further increase in pH to very high values.