Identification of N‐Acetylgalactosamine in Carbohydrates of Xenopus laevis Testis

Abstract

Identification of glycans in amphibian testis has shown the existence of N-acetylgalactosamine (GalNAc)-containing carbohydrates. Labeling of the sperm acrosome with GalNAc-binding lectins has allowed the identification of GalNAc-containing glycans in this organelle. Futhermore, this specific labeling of the acrosome has allowed the study of acrosomal biogenesis by lectin histochemistry. However, the testis of Xenopus laevis has never been analyzed by lectin histochemistry to locate GalNAc-containing glycoconjugates. The aim of this work was to elucidate the expression of GalNAc in glycoconjugates of Xenopus testis using five specific lectins. The results showed that most of the lectins labeled the interstitium with variable intensity. However, labeling of the different spermatogenetic germ cell types showed different labeling patterns. Some lectins produced weak or very weak staining in germ cells, for example, horse gram Dolichos biflorus agglutinin, which labeled most of the germ cell types, and lima bean Phaseolus lunatus agglutinin, which weakly labeled only spermatogonia, but did not stain other germ cells. By contrast, Maclura pomifera lectin (MPL) moderately labeled all germ cell types, except mature sperm. Labeling with other lectins was seen only at later stages, suggesting variations involved in the spermatogenetic development. Thus, snail Helix pomatia agglutinin labeled spermatids, but neither spermatogonia nor spermatocytes, while soybean Glycine max agglutinin (SBA) labeled from preleptotene spermatocytes to later stages. The periphery of the acrosome was labeled with MPL and SBA, but no specific labeling of the acrosomal content was seen with any lectin. Thus, the GalNAc-binding lectins that have been used as acrosomal markers in some amphibians cannot be used in Xenopus testis, suggesting that acrosomal glycoconjugates in amphibians are species specific.

Lectin Histochemistry as a Tool to Identify Apoptotic Cells in the Seminiferous Epithelium of Syrian Hamster (Mesocricetus auratus) Subjected to Short Photoperiod

“…Lectin histochemical techniques have been widely used to study the pattern of the glycoconjugates present in the cells of the seminiferous epithelium in many species of vertebrate, including amphibians (Valbuena et al. , ,b), fish (Liguoro et al. ; Desantis et al.…”

“…Lectin histochemical techniques have been widely used to study the pattern of the glycoconjugates present in the cells of the seminiferous epithelium in many species of vertebrate, including amphibians (Valbuena et al 2010(Valbuena et al , 2011a, fish (Liguoro et al 2004;Desantis et al 2010), birds (Ballesta et al 1991;Bakst et al 2007;Pel aez and Long 2008), mammals (Arya and Vanha-Perttula 1985;Calvo et al 2000;Pinart et al 2001;Morales et al 2002;Desantis et al 2006;Parillo et al 2012) and humans (Arenas et al 1998). This histochemical technique has recently been used to identify changes in the pattern of glycoconjugates of various cell types in apoptosis (Taatjes et al 2008), in particular lectins with affinity for a-D-mannose and b-D-galactose (Bilyy et al 2004).…”

Histochemical identification of sialylated glycans in Xenopus laevis testis

“…In some previous works, we have shown that the acrosome of Xenopus is unreactive for other Fucose‐, Galactose‐ and N ‐acetylgalactosamine‐binding lectins (Valbuena et al. , ,b). The acrosome is a specialized cell organelle that has plenty of glycoproteins and, in most species, is very reactive to a lot of lectins (Yamamoto, ; Arya & Vanha‐Perttula, , , ; Lee & Damjanov, ; Malmi & Söderström, ; Ballesta et al.…”

Microvascular anatomy of testes in the adult pipid frog, Xenopus laevis Daudin: A scanning electron microscopic study of vascular corrosion casts

“…Xenopus laevis increasingly serves as an in-vitro and in-vivo model for the screening of Endocrine Disruptor Chemicals (EDCs) that affect hypophysis and thyroid glands as well as gonads, and as a model animal species to study reproductive toxicity of phytoestrogens (Cong et al, 2006). For these reasons, gonadal histomorphology (Cevasco et al, 2008;Kalt, 1976) and histochemistry (Valbuena et al, 2012(Valbuena et al, , 2010Valbuena, Alonso, Diaz Flores, et al, 2011;Valbuena, Alonso, Madrid, & Diaz Flores, and Saez, 2011b) are well documented in adult Xenopus. However, only one of the above-mentioned studies has paid attention to the testicular blood vessels (Cevasco et al, 2008).…”

“…Anatomy, morphology, fine structure, histochemistry and endocrine regulation of the anuran testes have been studied in great detail (e.g., Lofts, ; Duellman & Trueb, ; Valbuena, Madrid, Hernandez, & Saez, ; Valbuena, Alonso, Diaz Flores, Madrid, & Saez, ; Valbuena et al, ; Villagra, Ramos, Cisint, Crespo, & Fernandez, ). However, little is known on the vascular anatomy of the anuran testes.…”