INVESTIGATIONS INTO THE MOLECULAR BIOLOGY OF LEISHMANIA

利什曼原虫是一种寄生原生动物，它的部分生命周期是 哺乳动物巨噬细胞内的专性细胞内寄生虫 主持人。哺乳动物的宿主感染发生在一次静脉注射的血餐中 携带有鞭毛的前鞭毛体的有机体的沙蝇。这个 前鞭毛体进入巨噬细胞，在那里它经历分化到 无鞭毛的无鞭毛体。一些补充方法将 用来研究分子事件在从 从前鞭毛体到无鞭毛体，并确定这种转变是如何允许的 维持寄生虫和寄生虫之间成功的寄生相互作用 巨噬细胞。从分离的mRNAs中构建重组DNA文库 来自前鞭毛体和无鞭毛体的序列将被用来鉴定 仅以一种或另一种形式存在。CDNAs分子 包含这些序列将被用来分析基因的调控 在前鞭毛体向无鞭毛体分化过程中的表达。这个 包含部分编码信息的序列 以每种形式独占表达的多肽将被插入到 重组表达载体PMR100产生融合蛋白的研究 β-半乳糖苷酶。这些融合蛋白将被用来制造抗体 针对寄生虫抗原的。然后抗体将被用来跟随 在感染过程中有机体的分化，以确定 影响巨噬细胞存活的机制，并定义 宿主细胞表面发生的变化。

Leishmania is a parasitic protozoan which spends part of its life cycle as an obligate intracellular parasite within the macrophage of its mammalian host. Mammalian host infection occurs during a bloodmeal of a phlebotomine sandfly carrying the flagellated promastigote form of organism. The promastigote enters the macrophage where it undergoes differentiation to the nonflagellated amastigote form. A number of complementary methods will be used to study the molecular events involved in the transformation from promastigote to amastigote and to determine how this transition permits maintenance of a successful parasitic interaction between the parasite and the macrophage. Recombinant DNA libraries generated from mRNAs isolated from promastigotes and amastigotes will be used to identify sequences which are present exclusively in one or the other form. cDNA molecules containing these sequences will be used to analyze regulation of gene expression during the promastigote to amastigote differentiation. The sequences containing a portion of the coding information for those polypeptides expressed exclusively in each form will be inserted into the plasmid expression vector PMR100 to generate fusion proteins containing Beta-galactosidase. These fusion proteins will be used to make antibodies specific for parasite antigens. The antibodies will then be used to follow differentiation of the organism during infection, to determine the mechanism by which survival in the macrophage is effected, and to define alterations which occur in the surface of the host cell.