扩张莫尼茨绦虫(圆叶目:裸头科)节间腺的超微结构及组织化学

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.%用光学显微镜和透射电子显微镜观察了扩张莫尼茨绦虫节间腺形成过程的精细结构及一些组化变化.结果表明:节间腺是扩张莫尼茨绦虫皮层的特化部分,由节片后缘的皮层及其邻近细胞体向绦虫实质组织中陷入开始其形成过程,随着虫体发育的进行,新的陷入不断形成,原陷入的部分不断脱离皮层形成簇状腺体结构.节间腺的数目随着体节的发育不断增加,幼节中仅有少数几个(6～9个),而远端的孕节中多于100个.电镜下可见腺细胞体由细胞质管与腺皮层相联,簇状腺体结构为一合胞体形态,腺细胞体围绕并开口于椭球体或不规则形状的皮层腔中.离腺皮层远的腺细胞体电子密度高并含有与腺皮层相应的典型分泌颗粒,而靠近腺皮层的腺细胞体电子密度低,所含分泌颗粒较少.扩张莫尼茨绦虫节间腺的组化性质尚不完全清楚.糖与蛋白质等组化结果不稳定,随染液pH值及染色时间的变化等多种因素而改变.基于我们的研究及其他研究者的观察表明,节间腺可能参与外源基质形成虫卵的转运,同时他们可能在虫体节片脱落及虫卵溢出时起作用.