Ultrastructural localisation of carbohydrates in four myxosporean parasites.

The existence and localisation of carbohydrates in four myxosporean parasites was investigated at transmission electron microscope, using lectin histochemistry techniques. The Myxosporea studied showed different lectin binding patterns. N-acetyl-glucosamine or its polymers were predominant in the valves of Leptotheca sp. and were also present in Sphaerospora dicentrarchi and Polysporoplasma sparis ones. Mannose and/or glucose terminals were mainly detected in S. dicentrarchi and P. sparis valves. Polar capsule walls were intensively recognised by Con-A is S. dicentrarchi and with medium intensity in P. sparis and Leptotheca sp. The polar filament was scarcely labelled except in Leptotheca sp. with BS-I. The sporoplasms of the studied parasites were stained with all the lectins tested with each myxosporea, except those of Leptotheca sp. with BS-I. Some structures of the developmental stages of Zschokkella mugilis and Leptotheca sp. were stained with BS-I. The possible role of these carbohydrate terminals found in the studied Myxosporea is discussed.