CELL-SURFACE HYDROPHOBICITY AND CELL-SURFACE CHARGE OF AZOSPIRILLUM SPP

The cell-surface charge and cell-surface hydrophobicity of 10 strains of Azospirillum spp. were evaluated by the aqueous, two-polymer phase partitioning assay. Azospirillum spp. had moderate cell-surface hydrop hobicity and charge, lower than known values for human pathogens. The hydrophobicity and charge values were higher in solid than in liquid m edia. A general pattern of modifying hydrophobicity and charge by exte rnal treatments of the cells of all strains was not found, but various chemicals, temperatures, and enzymatic treatments changed the cell-su rface hydrophobicity and charge in different strains. A similar hydrop hobic protein was isolated, and partially characterized, from two stra ins of A. brasilense and one strain of A. lipoferum. This study propos es: (i) cell-surface hydrophobicity and charge of Azospirillum spp. ca n be affected by external treatments of the bacterium cell, and (ii) h ydrophobicity and charge may play a role, perhaps small, in the primar y adsorption of Azospirillum spp. to surfaces.