Biological activity of chitosan-sugar hybrids: Specific interaction with lectin

The specific interactions between lectins and chitosan-sugar hybrids, the s ynthesized chitosan derivatives linking carbohydrate residue to the amino g roup of chitosan, were investigated. The specific bindings of chitosan-L-fu cose (Fuc) hybrid with Ulex europaeus agglutinin I (UEA I, a lectin specifi c to L-Fuc), and chitosan-N-acetyl-D-glucosamine (D-GlcNAc) hybrid with Con canavalin A (Con A, a lectin specific to D-glucose, D-mannose and D-GlcNAc) , were confirmed by a surface plasmon resonance technique. The microscopic observation of Pseudomonas aeruginosa, which was preincubated with the fluo rescein isothiocyanate-labeled chitosan-L-Fuc hybrid, showed bacteria aggre gation. The aggregation was thought to be resulted from the specific intera ction of the L-Fuc residue of the hybrid with PA-II lectin on the surface o f P. aeruginosa. The chitosan-L-Fuc hybrid inhibited P. aeruginosa growth m ore effectively in comparison with the other hybrids or unmodified chitosan . The enhancement of antimicrobial activity of chitosan-L-Fuc hybrid could be attributed to the specific binding between PA-II lectin of P, aeruginosa and L-Fuc residue of the L-Fuc hybrid. Copyright (C) 2000 John Wiley & Son s, Ltd.