Lectin-binding pattern of Senegalese sole Solea senegalensis (Kaup) testis

The localization and characterization of oligosaccharide sequences in the testis of Senegalese sole Solea senegalensis was investigated using 12 lectins in combination with KOH saponification and sialidase digestion (K-s). The interstitial compartment contained all the sugar residues investigated, those bearing oligosaccharides terminating with sialic acid (Neu5Ac) alpha 2,3Gal beta 1,4GlcNAc, Neu5AcGalNAc alpha 1,3(LFuc beta 1,2) Gal beta 1,3/4GlcNAc beta 1 and GalNAc alpha 1,3(LFuc1,2) Gal beta 1,3/4GlcNAc beta 1 being more abundant in the medullar region than in the cortex. The melanomacrophage centres found in the interstitial compartment displayed glycans terminating with Gal beta 1,3GalNAc. The basal lamina separating the germinal and interstitial compartments exhibited glycans with terminal/ internal mannose, internal beta GlcNAc, and terminal Neu5Ac alpha 2,6Gal/GalNAc, and Neu5AcGal beta 1,3GalNAc, Gal beta 1,3GalNAc (PNA), Gal beta 1,4GlcNAc, GalNAc, alpha Gal, and alpha L-Fuc. In the germinal compartment, the Sertoli cells expressed only glycans terminating with Neu5Ac alpha 2,3Gal beta 1,4GlcNAc in the apical and supranuclear lateral surface of the spermatonial cysts located in the distal part of the seminiferous lobules. Primary spermatocytes exhibited oligosaccharides terminating with Gal beta 1,3GalNAc and alpha GalNAc in the cytoplasm and nucleus, respectively. The spermatids contained highly mannosylated glycans terminating with GalNac, alpha Gal, and alpha L-Fuc. The head of spermatozoa expressed a more complex glycosylation pattern characterized by the additional presence of oligosaccharides terminating with Neu5Ac alpha 2,3Gal beta 1,4GlcNAc, Neu5AcGal beta 1,3GalNAc, Neu5AcGalNAc alpha 1,3(LFuc alpha 1,2)Gal beta 1,3/4GlcNAc beta 1, GalNAc alpha 1,3(LFuc alpha 1,2)Gal beta 1,3/4GlcNAc beta 1. The comparison with previous lectin histochemical studies carried out in other fish species reveals a specific glycosylation pattern of Senegalese sole testicular structures and spermatozoa head.