Interaction between colloidal montmorillonite and cells of rhizobium species with different ionogenic surfaces

Abstract

1. 1. In all cultures of Rhizobium spp. examined, sodium montmorillonite increased the electrophoretic mobility of cells to a point where the cell mobility approached that of the sodium montmorillonite itself. 2. 2. Cells whose surface ionogenic groups are exclusively acidic (carboxyl) consistently adsorbed more clay per unit area of cell surface than cells with a more complex carboxyl-amino ionogenic surface. A predominantly edge-to-face association between clay platelets and the bacterial surface is suggested to account for the large amount of montmorillonite apparently adsorbed per unit area of cell surface of both types of bacteria. 3. 3. The significance of a clay envelope around each cell is discussed in the light of observed protective effects on bacteria by montmorillonite.