THE ADHESIVE DROPLET OF CAPILLICONIDIA OF BASIDIOBOLUS-RANARUM EXHIBITS UNIQUE ULTRASTRUCTURAL FEATURES

The capilliconidia of Basidiobolus ranarum produce an apical droplet o f extracellular material that aids in dispersal by arthropods, such as mites and termites. Electron microscopic examination of the adhesive material comprising the haptor of capilliconidia has shown it to consi st of an electron-dense band directly around the capilliconidial beak from which sinuous fibrous filaments extend radially. These filaments are partially digestible with proteinase-K and measure 18-20 nm wide b y 3-4 mum long. Interspersed among the filaments are double membrane-b ound ovoid organelles that are 0.2-0.3 mum x 0.3-0.4 mum and which con tain electron-dense granular contents. Overlying the layer of sinuous filaments is a looser layer of coarsely fibrogranular material that, i n turn, is covered with an outermost layer of densely granular materia l. What are interpreted to be earlier stages of adhesive formation exh ibit an almost homogeneous appearance of the haptor material. No clear ly defined wall or membrane delimits the droplet surface. A comparison is made between this adhesive material and that reported for other fu ngi.