Ultrastructure and histochemistry of interproglottidal glands in Moniezia expansa (Cyclophyllidea: Anoplocephalidae)

摘要

The interproglottidal glands of Moniezia expansa had been examined by light- and transmission electron microscopy(LM and TEM). The glands are specialised portions of the tegument and are first formed by infoldings of the surface tegument and their subjacent cell bodies into the parenchyma along the posterior margin of each immature proglottid. As development proceeds, new crypt-like infoldings of tegument are formed and the older ones separate from the tegument to become rosette-like glandular structures. The number of these glands per proglottid increases down the strobila such that there are several of them in the proximal immature proglottids but over a hundred in the distal gravid proglottids. Under TEM, different kinds of secretory granules can be seen in the cytoplasm of the glandular cell bodies and in the connecting glandular tegument. Each glandular complex is syncytial, glandular cell bodies surround and open into an elliptical-spherical or irregular-shaped tegumental cavity. Glandular cell bodies which are distant from the glandular tegument are much more electron-dense and contain typical secretory granules of the tegument proper, while the cell bodies near the glandular tegument are less electron-dense and contain fewer secretory granules. It is suggested that interproglottidal glands may be involved in translocation of exogenous substrates to the forming eggs and could also have roles in proglottid detachment in gravid strobila [ Acta Zoologica Sinica 49 (5): 656 - 662, 2003].