Adhesive Material of the Hyphopodia of Buergenerula spartinae

Abstract

An electron-dense extracellular material with fibrillar strands functions as the adhesive material for the attachment of the hyphopodia of Buergenerula spartinae to surfaces. This adhesive penetrates the pores of polycarbonate membranes and also attaches the hyphopodia to glass surfaces. Hyphopodia are bound tightly to surfaces and most cannot be removed when washed under running water even after soaking overnight in water at 26 C, 37 C, or 90 C. Incubation in 0.5% pectinase and 0.2 M citrate buffer at 37 C removed few hyphopodia. Substantial numbers of hyphopodia, however, could be removed from glass coverslips by presoaking in 0.5% protease, 0.2 M phosphate buffer, 0.5% hemicellulase, or 0.5% ammonium oxalate followed by rinsing in water. The adhesive material of the hyphopodia did not stain at the ultrastructural level for polysaccharides with the alkaline bismuth, phosphotungstic acid, or ruthenium red techniques. Staining did occur with ammoniacal silver nitrate which is specific for positively charged basic proteins. Enzymatic digestion followed by electron microscopic observation indicated the adhesive material was digested by protease. Pectinase and hemicellulase had no apparent effect. These results suggest that the adhesive material of the hyphopodia of B. spartinae contains positively charged basic proteins.