Spermatogenesis and the role of Sertoli cells in the freshwater snail Biomphalaria glabrata

Abstract

The various stages of spermatogenesis and the Sertoli cells of Biomphalaria glabrata were studied with histochemical and electron microscope techniques. During spermatogenesis a manchette of microtubules is formed around the nucleus and the mid-piece of the spermatids. This manchette becomes helically coiled and probably plays an important role in the spiralisation of the nucleus and of the mitochondrial sheath. During spermatogenesis so-called chromatoid bodies (CB) occur, which consist of arginine-rich proteins. These CB disintegrate during the early spermatid stage. The results suggest that the CB are either involved in histone transition or in the formation of microtubules. The remaining cytoplasm of the spermatids is phagocytised by the Sertoli cells. Apparently this process of phagocytosis is an important part of the mechanism of spermiation. Morphological measurements of the Sertoli cells showed that the relative volume of most organelles decrease during spermatogenesis, indicating a general decrease in cell activity. Possible functions of the Sertoli cells, such as transportation and nutrition of spermatogenic cells and hormone production, are discussed. It is concluded on the basis of the histochemical and ultrastructural observations that the Sertoli cells are involved in the nutrition of spermatogenic cells. It seems unlikely that they are hormone producing cells.

Testis follicles ultrastructure of three species of terrestrial isopods (Crustacea, Isopoda Oniscidea)

“…In the cytoplasm of the nurse cells numerous irregular cisternae of R.E.R, Golgi fields, mitochondria and vesicles with heterogeneous content are present thus clearly demonstrating their secretory activity. In parallel to the secretion activity, the nurse cells are protagonists of an intense phagocytosis of the residual fragments of spermatids cytoplasm, demonstrated by the presence in their cytoplasm of numerous heterophagic vacuoles and multilamellar bodies; an activity, this, common to the Sertoli cells of vertebrates (Grier, 1993;Morales and Clermont, 1993;Pudney, 1993;Chung, 2008;Lebelo and van der Horst, 2010;) and invertebrates (De Jong-Brink et al, 1977;Blades-Eckelbarger and Youngbluth, 1982;Buckland-Nicks and Chia, 1986;Hinsch, 1993a,c;Gabala, 2006). The substances derived from these phagocytized bodies are believed to be used as nutrients to spermatogenic cells (Morales and Clermont, 1993;Pudney, 1993;Hinsch, 1993a,b,c;Guraya, 1995).…”

“…While in many invertebrates (Adamiec, 1975;De Jong-Brink et al, 1977;Szöllösi and Marcaillou, 1977;Hinsch and Dehn, 1979;Hinsch, 1992Hinsch, , 1993aChow et al, 1991;Witalis, 1993) as well as in the Isopoda Valvifera (Gabala, 2006) the Sertoli cells extends their processes into the lumen of the testicles and take a direct contact with the germ cells, in this region of the follicle testis of terrestrial isopods, the Sertoli cells have always a regular shape, do not form processes and then never take a direct relationship with the spermatogonia and, moreover, do not exhibit signs of secretory activity. Their role towards the germ cells remains, therefore, to discover.…”

Establishment of the dominant lethal test in the freshwater mollusk Biomphalaria glabrata (Say, 1818)

“…These crossings were sufficient to detect the mutagenicity of both compounds. The stages of gametogenesis in gastropods are, essentially, similar to those observed in mammals and morphologically well characterized [26,32,33], but its chronology has not been established. Thus, additional crossings to determine the affected stages of spermatogenesis were not done; these effects were estimated from the time-response curve of ovogenesis obtained by the analysis of the wild-type snails offspring.…”

The ultrastructural characteristics of spermatogenesis inOnchidium struma(Pulmonata: Onchidiidae) and its functional adaptation

“…For instance, no microtubules are visible when the nucleus of C. chinensis (Yan et al 2004) is changing. In contrast, De Jong-Brink et al (1977) found that in Biomphalaria glabrata (Say, 1818), there are many microtubules surrounding the nucleus when the nucleus is transforming, and microtubules disappear when the transformation is completed. Ying et al (2008) found that microtubules surround the nucleus of sperm in O. struma.…”