Glycoconjugates of the urodele amphibian testis shown by lectin cytochemical methods

Abstract

Lectin histochemistry is a useful method that allows the in situ identification of the terminal sugar moieties of the carbohydrates that form the glycoconjugates. Moreover, when it is combined with chemical or enzymatic deglycosylation pretreatments, lectin histochemistry can be employed to determine if carbohydrates are linked to the protein core by means of an N- or O-glycosidic linkage or, indeed, to partially sequence the sugar chains. One of the most interesting model organs for the study of spermatogenesis is the amphibian urodele testis. However, this organ has not been very widely investigated with lectin histochemical research. In the last few years, we have carried out a research project to identify and locate glycoconjugates in the testis of the urodele Pleurodeles waltl, the Spanish newt, as a first approach to identify possible carbohydrates with key roles in spermatogenesis. Our findings reveal some glycan chains located in a fusome-like structure in early (diploid) germ cells, oligosaccharides with terminal GalNAc in the acrosome, the occurrence of glycan modifications in the acrosomal contents during spermiogenesis, and changes in glycan composition of follicle and interstitial cells during the spermatogenetic cycle. Furthermore, the similar labeling pattern of follicle and duct cells supports the hypothesis for a common origin of both cell types.

Identification of N‐Acetylgalactosamine in Carbohydrates of Xenopus laevis Testis

“…In the present work, spermatogonia were labeled by MPL, DBA, and LBA, while spermatocytes were positive for MPL, DBA, and SBA. In previous works using other amphibians, the presence of GalNAc in spermatogonia has been shown (Sáez et al,2000b,2004).…”

“…There the germ cells synchronously develop forming clusters, called cysts or follicles, each one being enclosed by a capsule formed by follicle (Sertoli) cells, which resemble fibroblasts (Lofts,1974). In recent studies, we have described that some amphibians show a strong expression of GalNAc‐containing glycoconjugates in the acrosome of the developing spermatids (Sáez et al,1999,2004; Valbuena et al,2008). However, Xenopus laevis is the amphibian model most extensively used in biological research, but no report exists about the expression of GalNAc‐containing glycans in the testis of this species.…”

Primordial Germ Cells (Spermatogonial Stem Cells) of Bullfrogs Express Sex Hormone-Binding Globulin and Steroid Receptors during Seasonal Spermatogenesis

“…Thus, PGC is the term used in this study and in others that we conducted previously [Sasso-Cerri et al, 2004. This term was used in a classical morphological study in amphibians [Schindelmeiser et al, 1983] and has been maintained in more recent studies [Paniagua et al, 1990;Arenas et al, 2001;Sáez et al, 2004;Flament et al, 2009]. According to Flament et al [2009], some species of amphibians might be used for the study of factors required to maintain PGCs in adult testes as well as factors triggering their differentiation.…”

Glycomolecule Modifications in the Seminiferous Epithelial Cells and in the Acrosome of Post‐testicular Spermatozoa in the Alpaca

“…Modifications of acrosomal glycoproteins have been evidenced in the above mammalian and also non‐mammalian species (Ballesta et al. 1991; Labate and Desantis 1995; Sáez et al. 2004) but it is not possible to display a common pattern of glycosilation during acrosomal development.…”

“…2006), humans (Lee and Damjanov 1985; Arenas et al. 1998), lizards (Labate and Desantis 1995), amphibians (Sáez et al. 2004), turkeys (Bakst et al.…”