Structure and function of the spermatheca in a snail host of schistosomiasis, Biomphalaria glabrata

Abstract

The histochemistry and ultrastructure (SEM and TEM) of the spermatheca of Biomphalaria glabrata was investigated to elucidate the function of this organ and to compare its structure and function to similar organs found in other species. The spermatheca has a debris-filled lumen surrounded by a thin wall of tissue. The cells adjacent to the lumen are of three columnar epithelial cell types. Two cell types have abundant microvilli and mammalian cell-like organelle distribution and morphology. The above cell types differ in the electron density of their cytoplasms, nuclear morphologies, and organelle content. The third cell type differs from the other two in its cytoplasmic makeup. However, the most distinctive difference is the presence of large numbers of cilia at the apical surface with no evidence of microvilli. These columnar cells rest on a basal lamina adjacent to a two to three cell thick muscle layer. The entire organ is surrounded by an adventitia of unusual morphology. Histochemical investigation demonstrated that DNAase, RNAase, and protease are present in the lumen, alkaline phosphatase is associated primarily with the microvilli, small amounts of acid phosphatase are concentrated in the midcell area of the columnar epithelium, and ATPase activity is localized in the muscle cells and just below the absorptive surface of the microvillous cells. The luminal contents and adventitial areas are Sudan Black B positive, all areas of the lumen and organ wall are PAS positive, the cell nuclei and amorphous masses in the lumen showed Feulgen staining, and large vesicles in the columnar cells were Oil Red O positive. Apparently, the spermatheca of B. glabrata is both a digestive and absorptive structure. Although this organ shares functional similarities with those found in opisthobranchs and terrestrial pulmonates, the epithelia of the spermatheca differ dramatically in these groups.

Differential tissue development during embryogenesis and regeneration in an annelid

“…In E. japonensis, ALP activity was also observed in various other tissues. Among them, spermatheca has been reported to be ALP-positive in snails (Rogers and Reeder, 1987), and the spots in the prostomium (Fig. 2B,C) might correspond to ALP-positive photoreceptors in cephalopods (Romero-Saravia and Hamdorf, 1983).…”

The fate of received sperm in the reproductive tract of a hermaphroditic snail and its implications for fertilisation

“…Received sperm can either be digested in the bursa copulatrix (e.g. Horstmann 1955;De Jong-Brink 1969;Rogers and Reeder 1987;Clelland et al 2001) or be stored for fertilising eggs (Cain 1956). In Basommatophora, sperm storage allegedly occurs at the junction where the hermaphroditic duct divides into a male and female tract, called the carrefour region, and where the fertilisation pouch is located (De Jong-Brink 1984;Geraerts and Joosse 1984).…”

Bursa tract diverticulum in the hermaphroditic land snailArianta arbustorum (Stylommatophora: Helicidae): Morphology, function, and evolutionary implications

“…The bursa was originally thought to function as the site of allosperm storage (Meisenheimer, 1912) or sperm activation (cf. Rogers and Reeder, 1987). However, ultrastruc-tural and histochemical studies suggested that its function may be the extracellular digestion and subsequent resorption of excess gametes (primarily allosperm) and other reproductive products, such as secretions from the albumen gland, oviductal glands, and seminal channel (Németh and Ková cs, 1972;Rogers et al, 1980;Gomez et al, 1991).…”