Plasma membrane glycoproteins during spermatogenesis and in spermatozoa of some fishes.

Plasma membrane glycoproteins were analyzed during spermatogenesis and in the spermatozoa of the teleost fish Xiphophorus maculatus and of the Elasmobranch Schroederichthys chilensis. The analysis was undertaken using the fluoresceinated lectins concanavalin A (ConA) and wheat germ agglutinin (WGA) to detect glycoproteins in the plasma membrane using confocal laser microscopy. In Xiphophorus, a species with acrosomeless spermatozoa, primary spermatocytes and rounded shaped spermatids showed that the whole cell surface was labeled by both lectins. As spermiogenesis proceeded surface glycoproteins diminished and in mature spermatozoa a discrete and non-random localized fluorescence was observed exclusively on the surface of the spermatozoon head after the employ of ConA and WGA. In the elasmobranch Schroederichthys chilensis the spermatozoon displays an acrosome as a small vesicle. After ConA and WGA labeling, the region of the plasma membrane that covers the acrosome was the only fluorescent region in the gamete. The physiological significance of plasma membrane glycoproteins is discussed regarding spermatozoon physiology.