title: Localization of egg-surface carbohydrates and fertilization in Discoglossus pictus (Anura).
abstract: The distribution of carbohydrates on the unfertilized egg surface in regions receptive or refractory to sperm penetration was analysed in the anuran amphibian Discoglossus pictus by means of a panel of lectins at the level of both the light and electron microscope. Results showed that a gradient of fucosyl-containing glycoconjugates was present at the pre-determined site of sperm entrance and topographically overlapped a similar gradient in sperm entry previously reported. Of a number of simple and complex carbohydrates examined for their ability to inhibit fertilization, fucoidan, ascophyllan and fucose affected the sperm-egg interaction. These sugars, although not decreasing sperm motility or triggering the acrosome reaction, rendered the sperm unable to penetrate the egg jelly coats. The possible involvement of fucosyl-containing glycoconjugates in the sperm-egg interaction in Discoglossus pictus is discussed.
authors.affiliation: Dipartimento di Biologia Evolutiva e Comparata, Università di Napoli "Federico II", Via Mezzocannone 8, I-80134 Napoli, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Gualtieri
authors.forename: P
authors.initials: P
authors.lastname: Andreuccetti
mesh_terms: D000818:Animals; D001001:Anura / Q000378:metabolism*; D002241:Carbohydrates / Q000032:analysis*; D005260:Female; D005643:Fucose / Q000032:analysis; D006001:Glycoconjugates / Q000737:chemistry* / Q000502:physiology; D037102:Lectins; D008297:Male; D008854:Microscopy, Electron; D009865:Oocytes / Q000737:chemistry*; D011134:Polysaccharides / Q000032:analysis; D013084:Sperm-Ovum Interactions; D013499:Surface Properties
chemical_list: D002241:Carbohydrates; D006001:Glycoconjugates; D037102:Lectins; D011134:Polysaccharides; C058519:ascophyllin; D005643:Fucose; C007789:fucoidan