Smith T G, Desser S S
Department of Zoology, University of Toronto, Ontario, Canada.
J Eukaryot Microbiol. 1998 Jul-Aug;45(4):419-25. doi: 10.1111/j.1550-7408.1998.tb05093.x.
The cystic and merogonic stages of the haemogregarine Hepatozoon sipedon, infecting Northern water snakes (Nerodia sipedon sipedon) and Northern leopard frogs (Rana pipiens), respectively, in Ontario, Canada, were investigated by transmission electron microscopy. Cysts, which were observed in the liver of Northern leopard frogs (Rana pipiens) after these anurans ingested mosquitoes (Culex pipiens) containing oocysts of the parasite, harboured two cystozoites, each of which contained a large crystalloid inclusion anterior to the nucleus. Two types of meronts were observed in snakes that were fed the liver of infected frogs. Macromeronts, which matured in endothelial cells of the liver approximately 16 d after snakes ingested infected frogs, contained about 50 large macromerozoites. Macromerozoites emerged from macromeronts, entered the bloodstream of the snake, and reinfected endothelial cells. Micromeronts, which matured about 34 d post-inoculation, contained about 150 micromerozoites that infected erythrocytes and transformed into gamonts. The ultrastructural features of micromeronts and macromeronts differed only slightly: immature macromeronts and macromerozoites contained numerous amylopectin and lipid inclusions, whereas immature micromeronts and micromerozoites did not contain amylopectin inclusions and featured fewer, smaller lipid inclusions. A comparison of cystic stages among Hepatozoon species in different groups of vertebrates is presented with respect to their structure and evolutionary significance.
利用透射电子显微镜对感染加拿大安大略省北部水蛇（Nerodia sipedon sipedon）和北部豹蛙（Rana pipiens）的血簇虫肝簇虫（Hepatozoon sipedon）的包囊期和裂殖生殖期进行了研究。在这些无尾两栖类动物摄入含有该寄生虫卵囊的蚊子（库蚊）后，在北部豹蛙（Rana pipiens）的肝脏中观察到包囊，每个包囊内含有两个囊殖子，每个囊殖子在细胞核前方都含有一个大的晶体包涵体。在喂食感染青蛙肝脏的蛇体内观察到两种类型的裂殖体。大型裂殖体在蛇摄入感染青蛙后约16天在肝脏内皮细胞中成熟，含有约50个大型裂殖子。大型裂殖子从大型裂殖体中逸出，进入蛇的血液，并再次感染内皮细胞。小型裂殖体在接种后约34天成熟，含有约150个感染红细胞并转化为配子体的小型裂殖子。小型裂殖体和大型裂殖体的超微结构特征仅略有不同：未成熟的大型裂殖体和大型裂殖子含有大量支链淀粉和脂质包涵体，而未成熟的小型裂殖体和小型裂殖子不含支链淀粉包涵体，脂质包涵体数量较少且较小。本文就不同脊椎动物类群中肝簇虫属物种的包囊期结构及其进化意义进行了比较。
