The acrosomal membrane system of boar spermatozoa--morphological and biochemical studies

The distribution of the cell surface saccharides with alpha-glycosidically linked mannose and terminal galactose was displayed by fluorescence microscopical examinations with FITC-conjugated concanavalin A and Ricinus communis agglutinin-120. The lectin binding sites of the inner cellular membranes--inner and outer acrosomal membrane--were ultrastructurally localized by electron microscopical studies using the lectin-peroxidase technique. It could be demonstrated that both acrosomal membranes contain covalently bound carbohydrates. In order to characterize the acrosomal membrane components which are responsible for the binding to lectins, the outer acrosomal membrane was separated after homogenization by centrifugation through modified colloidal silica. The exposed membrane proteins were labelled by galactose oxidase mediated introduction of tritium into the carbohydrate side chains of the glycoproteins. After solubilization the membrane components were analysed by affinity chromatography and electrophoresis. For a general characterization the cholesterol/phospholipid ratio of ejaculated boar spermatozoa and the isolated membrane fraction was determined and some enzymatic activities were assessed.