Aldeyarbi Hebatalla M, Karanis Panagiotis
University of Cologne,Center for Anatomy,Institute I,Joseph-Stelzmann-Street 9,50937 Cologne,Germany.
University of Cologne,Medical School,Cologne,Germany.
Parasitology. 2016 May;143(6):749-61. doi: 10.1017/S0031182016000275. Epub 2016 Mar 3.
The sexual stages and new oocysts development of Cryptosporidium parvum were investigated in a cell-free culture system using transmission electron microscopy (TEM). Sexual development was extremely rapid after inoculation of oocysts into the medium. The process began within 1/2-12 h and was completed with new oocyst formation 120 h post-inoculation. The macrogamonts were bounded by two membranes and had amylopectin granules and two distinct types of wall-forming bodies. The microgamonts had a large nucleus showing lobe projections and condensation of chromatin, giving rise to peripherally budding microgametes. The microgametes contained a large area of granular substance containing groups of microtubules surrounding the electron-dense nucleus. In some instances, the dividing microgamy was observed in cell-free cultures with no preceding merogonic process. Fertilization was observed with the bullet-shaped microgamete penetrating an immature macrogamont at 24 and 216 h. The new thin- and thick-walled oocysts had a large residuum with polysaccharide granules and sporogony noted inside these oocysts. Novel immature four-layer walled thick oocysts with irregular knob-like protrusions on the outer layer resembling the immature Eimeria oocysts were also observed. The present study confirms the gametogony and sporogony of C. parvum in cell-free culture and describes their ultra-structure for the first time.
利用透射电子显微镜（TEM）在无细胞培养系统中研究了微小隐孢子虫的有性阶段和新卵囊发育。将卵囊接种到培养基后，有性发育极其迅速。该过程在接种后1/2 - 12小时内开始，并在接种后120小时形成新卵囊时完成。大配子体由两层膜包围，有支链淀粉颗粒和两种不同类型的壁形成体。小配子体有一个大核，显示出叶状突起和染色质凝聚，产生周边出芽的小配子。小配子含有大量颗粒物质，其中含有围绕电子致密核的微管群。在某些情况下，在无细胞培养物中观察到小配子分裂，且没有先前的裂殖生殖过程。在24小时和216小时观察到子弹形小配子穿透未成熟大配子体的受精现象。新的薄壁和厚壁卵囊有一个大的残体，带有多糖颗粒，并且在这些卵囊中观察到孢子生殖。还观察到新型未成熟的四层壁厚卵囊，其外层有不规则的瘤状突起，类似于未成熟的艾美耳球虫卵囊。本研究证实了微小隐孢子虫在无细胞培养中的配子生殖和孢子生殖，并首次描述了它们的超微结构。
