An immunofluorescence study on lectin binding sites in gametes of Ectocarpus siliculosus (Ectocarpales, Phaeophyceae)

The distribution of binding sites for the lectins WGA, DSA. RCA I, PNA, AAA, MAA. SNA, GNA. and Con A in gametes of both sexes of the brown alga, Ectocarpus siliculosus (Dillw.) Lyngbye, was investigated by fluorescence microscopy. Digoxigenin-conjugated lectins and an FITC-anti-digoxigenin antibody were used as a high sensitivity detection system. Organelles and other distinct cellular domains could be distinguished by their binding specificities. Glycoconjugates associated with one flagellum were found to be associated with the axoneme by lectin binding to isolated flagellar apparatuses. In addition, changes in the distribution of carbohydrate epitopes during the attachment of gametes to the substratum were revealed by differential lectin binding.