SOME PHYSICAL INVESTIGATIONS OF THE BEHAVIOUR OF BACTERIAL SURFACES. XI. THE EFFECT OF PHENOL AND SUBSTITUTED PHENOLS ON THE ELECTROPHORETIC MOBILITY OF AEROBACTER AEROGENES.
Abstract 1. 1. The electophoretic mobility of cells of Aerobacter aerogenes , harvested early in the logarithmic growth phase, on treatment with phenol, p -alkyl phenols and p -halogenophenols in buffer solution, increases with increasing concentration of the phenol. 2. 2. The substituted phenols are more active than phenol, in that they produce changes of mobility similar to that produced by phenol, but at much lower concentrations. 3. 3. There is, for both series of substituted phenols, a parallel variation of bactericidal concentration and the concentrations required to produce a given mobility change of the cells. 4. 4. The variation of the mobility of phenol-treated young cells with pH indicates that at pH valeus exceeding 7, irreversible surface changes occur. 5. 5. Growth of cells in low concentrations of phenol produces no change in their electrophoretic mobility. Treatment of such cells in higher concentrations of phenol produces effects similar to those observed with normal cells. 6. 6. The results are discussed with reference to the variation of the capsular material (size and polysaccharide content) which occurs during the growth cycle, and the presence of phenoxy ions on the surface.