贝氏隐孢子虫在北京鸭体内发育的超微结构研究

贝氏隐孢子虫各期虫体均位于宿主粘膜上皮细胞的带虫空泡中。在虫体与上皮细胞接触处,虫体表膜反复折迭形成营养器。子孢子或裂殖子与粘膜上皮细胞接触后,逐步过渡为球形的滋养体;滋养体经2—3次核分裂、产生含4或8个裂殖子的两代裂殖体,裂殖体以外出芽方式产生裂殖子;裂殖子无微孔,顶端表皮形成3—4个环嵴,裂殖子进一步发育成为配子体;大配子体含有两种类型的成囊体。小配子呈楔形,无鞭毛和顶体,有一个致密的长椭圆形细胞核,小配子表膜内侧有9根膜下微管;孢子化卵囊内含四个裸露的子孢子和一个大残体。本文是有关鸭体内隐孢子虫超微结构的首次报导。

ULTRASTRUCTURAL STUDIES ON CRYPTOSPORWIUM BAILEYI IN BEIJING DUCK

The individual of Cryptosporidium baileyi goes every developmental stage of its life within an epithelial cell, surrounded by a parasitophorous vacuole which is formed by neighbouring microvilli, At the base of parasite, there is a convolutionary structure formed by folding of the parasite membrane which is named feeder organelle. The sporozoites and merozoites developed into spheroical trophozoites gradually after contacted with epithelial cells of mucous membrane. Through two or three nuclear divisions, the trophozoites developed into two-generation schizonts, involving eight or four achizoites, the first generation schizonts with eight merozoites and the second with four. The merozoites, the daughter schizonts, are formed by ectomerogony of schizont associated with the last nuclear mitosis. There is no micro per-foridum on the top of merozoite, where the pellicle forms 3-4 anular rings, and then, merozoites devolope into gametocytes. The macrogamont contains two forms of wall forming body. The microgamont without perforidium is wedge-shaped and unflagellated, and the dominating organelle is the big dense nucleus in elongated oval shape. Nine microtubules, spreading from the apical polar ring to the end in microgamete, are circularly arranged under the pellicle membrane. There are four naked sporozoites and one large residium in the sporolated oocysts. This is the first report on ultrastructure of Cryptosporidium baileyi in Beijing duck.