Effect of Chitosan on Membrane Permeability of Suspension-Cultured Glycine max and Phaseolus vulgaris Cells

Abstract

Treatment of suspension-cultured G. max cv. Harosoy 63 cells with soluble chitosan (20-500 .mu.g/l ml) increased membrane permeability as shown by leakage of electrolytes, protein and UV absorption material. Severe damage to the cell membrane by chitosan (100 and 500 .mu.g/ml) was also indicated by reduced staining with fluorescein diacetate and the leakage of fluroesceion from preloaded cells. Other basic polymers (poly-L-lysine, histone, DEAE-dextran, protamine sulfate and glycol chitosan) also increased permeability, whereas the basic monomers L-lysine and D-glucosamine and acidic or neutral polymers were not active. Chitosan-induced leakage was inhibited by divalent cations, the order of effectiveness being Ba2+ > Ca2+ > Sr2+ > Mg2+. Na polygalacturonate and Na poly-L-aspartate also reduced polycation-induced leakage, probably by formation of polycation-polyanion complexes. A chitosan-polygalacturonate complex precipitated on mixing solutions of the 2 polymers containing approximately equal numbers of galacturonate and glucosamine residues, but not with either polymer in excess. A similar concentration-dependent precipitation of chitosan by Na poly-L-aspartate occurred. Leakage from P. vulgaris cv. Grandessa cells was also induced by chitosan and was inhibited by Ca2+ and Na polygalacturonate. [Chitosan is a major component of the fungal cell wall in the zygomycetes and is believed to be released at the host-pathogen interface during infection.].