He Y X, Yu Q F, Yu P, Mao C S, Hu Y Q
Institute of Parasitic Diseases, Chinese Academy of Preventive Medicine, Shanghai.
Chin Med J (Engl). 1990 Jan;103(1):34-44.
The anterior part of Schistosoma japonicum cercaria is a specialized head organ which can slightly stretch out and retract. There are three different types of large unicellular glands in cercarial body, consisting of one head gland, 2 pairs of pre- and 3 pairs of postacetabular glands. These glands differ in position, gross feature, histochemistry and functions. Both polysaccharase and protease activities are demonstrated in the secretions from these glands. Mode of cercarial penetration is described in detail and the penetration is effected by a combination of lytic secretions and mechanical movements. The schematic representation of the process of cercarial penetration is presented. The dynamic distributions of schistosomula in skin at different time intervals after skin penetration in various mammalian hosts are shown. Some newly transformed schistosomula die while penetrating into the skin of 7 mammalian species and the mortality rate varies with the host species, and that can also be affected by the age of cercariae following emergence from the snail. Some physiological aspects between cercariae and newly transformed schistosomula are compared. In contrast to cercariae, schistosomula are saline-adapted and water-intolerant. They were modified histochemically and antigenically.
日本血吸虫尾蚴的前部是一个特殊的头部器官，可微微伸出和缩回。尾蚴体内有三种不同类型的大型单细胞腺，包括一个头腺、2对前腹腺和3对后腹腺。这些腺体在位置、大体特征、组织化学和功能方面存在差异。这些腺体的分泌物中都显示出多糖酶和蛋白酶活性。详细描述了尾蚴的侵入方式，侵入是由溶解性分泌物和机械运动共同作用实现的。给出了尾蚴侵入过程的示意图。展示了在不同哺乳动物宿主皮肤穿透后不同时间间隔内童虫在皮肤中的动态分布。一些新转化的童虫在侵入7种哺乳动物的皮肤时死亡，死亡率因宿主种类而异，并且也会受到尾蚴从螺体逸出后的年龄影响。比较了尾蚴和新转化童虫之间的一些生理方面。与尾蚴相比，童虫适应盐水且不耐水。它们在组织化学和抗原性方面发生了改变。
