CELL-SURFACE CHARGE AND CELL-SURFACE HYDROPHOBICITY OF COLLAGEN-BINDING AEROMONAS AND VIBRIO STRAINS

Partitioning in aqueous polymer two-phase systems of polyethylene glyc ol and dextran was used to detect and compare cell-surface charge and cell-surface hydrophobicity of Aeromonas hydrophila, A. caviae, A. sob ria, Vibrio cholerae, and V. anguillarum strains. These strains have c ell-surface components that bound either native or thermally denatured type I collagen (i.e., a mixture of the alpha 1+alpha 2 chains) and g elatin immobilized on latex beads. Our goals were: (1) to compare the possible relationship between the cell-surface charge/hydrophobicity a nd binding to collagen and (2) to evaluate the influence of the cultur e media on the expression of surface properties. There was no apparent relationship between cell-surface charge, cell-surface hydrophobicity , and binding to collagen. The expression of surface properties was de pendent on the culture media. There was no relationship between bindin g to immobilized collagen and binding to soluble I-125-labeled collage n. Particle-agglutination reactivity differed when using various colla gen-coated microbead preparations. There were general differences in t he particle-agglutination reactivity when collagen-coated latex beads were prepared using different coating procedures. The negative charge and hydrophobicity of the various collagen-coated microbead preparatio ns were also studied by partitioning in the two-phase system of polyet hylene glycol and dextran. Under these conditions, the alpha 1+alpha 2 collagen-chain mixture covalently immobilized on carboxy-modified lat ex beads was less hydrophobic and negatively charged than gelatin and native collagen immobilized on the same kind of latex beads. For latex beads passively coated with collagen preparations, the alpha 1+alpha 2 collagen-chain mixture was more hydrophobic than gelatin and native collagen. We suggest that for screening collagen-binding among Vibrio and Aeromonas strains, a reliable and sensitive particle-agglutination assay should consider the collagen preparation and the coating proced ure for the immobilization of collagen onto the latex beads. In this r egard, carboxy-modified latex beads coated with an alpha 1+alpha 2 col lagen-chain mixture gave the best results.