BIOCHEMICAL CYTOLOGY OF HOST-PARASITE INTERACTIONS IN PARASITIC PROTOZOA

利什曼原虫和弓形虫的细胞和分子生物学 作为细胞内寄生的模型被研究。重点放在 关于生物化学功能和基因结构的表征 它们的表面膜和分泌的蛋白质的作用 这些成分在寄生虫的生存和发育中起着重要作用。 一种编码锥虫表面膜独特酶的基因， 3‘-核苷酸酶已被鉴定、克隆和全序列测定 L.多诺瓦尼。类似地，从L. 多诺瓦尼分泌型酸性磷酸酶基因家族正在测序中。 这种酶在受感染的巨噬细胞中的作用也是 调查过了。设计了体外连续培养的方法。 大量培养感染性无鞭毛体(Am-) L.donovani和其他几个物种。这些都是 在细胞生物学和生物化学方面具有特点。在… 在分子水平上，已经确定了几个基因，它们是 由Am唯一或不同地表示--这些都在使用 作为探针研究寄生虫基因调控的分化和细胞 循环发展。此外，基因的一部分同时存在于两个表面 膜5‘-核苷酸酶和一种“分泌型”几丁质酶 用聚合酶链式反应进行鉴定和测序。最后，一种独特的5‘-核苷酸酶 在弓形虫的表膜中鉴定出 速殖子和一个聚合酶链式反应产生的探针被用来鉴定 这种蛋白质的基因。 目前的结果对新的发展具有相关性 诊断、化疗和免疫预防药物 这些重要的人类病原体。

The cell and molecular biology of both Leishmania and Toxoplasma are investigated as models of intracellular parasitism. Emphasis is placed on characterizing both the biochemical functions and gene structure of their surface membrane and secreted proteins toward defining the roles of these constituents in parasite survival and development. A gene encoding the unique, trypanosomatid surface membrane enzyme, 3'-nucleotidase has been identified, cloned and fully sequenced from L. donovani. Similarly, full length genomic clones from an L. donovani secretory acid phosphatase gene family are being sequenced. The role of this enzyme within infected macrophages is also being investigated. Methods were devised for the continuous in vitro cultivation of large quantities of infectious amastigotes (Am-) from L. donovani and several other species. These Am- are being characterized with regard to their cell biology and biochemistry. At the molecular level, several genes have been identified which are uniquely or differentially expressed by Am- and these are being used as probes to study parasite gene-regulated differentiation and cell cycle development. Further, a portion of a gene for both a surface membrane 5'-nucleotidase and a "secretory" chitinase have been identified and sequenced from PCR. Finally, a unique 5'-nucleotidase was identified in the surface membrane of Toxoplasma gondii tachyzoites and a PCR-generated probe is being used to identify the gene for this protein. The current results are of relevance toward the development of new diagnostic, chemotherapeutic and immunoprophylactic agents against these important human pathogens.