BIOCHEMICAL CYTOLOGY OF HOST-PARASITE INTERACTIONS IN PARASITIC PROTOZOA

利什曼原虫和锥虫的细胞生物学和生物化学 作为细胞内和细胞外寄生的模型进行研究， 分别 当宿主和寄生虫之间的所有相互作用发生时， 在寄生虫表面膜（SM）的水平上，重点是 放在：1）它的综合生化和生理 表征和2）确定其在寄生虫生存中的作用， 发展 一种76 KDa SM糖蛋白，具有推定的羧基载体 功能在L. donovani（Ld）前鞭毛体 一形状记忆 L-脯氨酸结合/转运蛋白，含有41个亚基的两个亚基 在Ld. 生物合成分泌 可溶性酸性磷酸酶（S-AcP）途径定位于两个 Ld pro-和amstigotes。 纯化S-AcP，并将前30 测定其N-末端氨基酸序列的残基。 基于该序列的寡核苷酸探针用于 鉴定并克隆S-AcP基因。 诱导型Ld SM 3 '- 核苷酸酶/核糖核酸外切酶被分离、纯化， 是43 kDa甘露糖基化糖蛋白。 抗体正在 用于筛选cDNA表达文库，以鉴定和克隆其 基因 LD SM 5 '-核苷酸酶被分离、纯化并显示 是含有两个72个亚基的甘露糖基化糖蛋白， 43 kDa。 此外，LD SM葡萄糖转运蛋白和 质子-ATP酶的鉴定和表征。 基于其 与其他系统中类似蛋白质的同源性， 合成保守功能区的寡核苷酸 作为探针来鉴定和克隆这两种基因， 利什曼原虫蛋白 目前的结果提供了进一步的功能表征， 寄生虫SM成分，这些可以作为潜在的 用于化疗和/或免疫诊断/预防的靶标。

The cell biology and biochemistry of Leishmania and Trypanosoma are investigated as models of intra- and extracellular parasitism, respectively. As all interactions between host and parasite occur at the level of the parasite surface membrane (SM), emphasis is placed on: 1) its integrated biochemical and physiological characterization and 2) defining its roles in parasite survival and development. A 76 KDa SM glycoprotein, with putative carboxyl-carrier functions was identified in L. donovani (Ld) promastigotes. A SM L-proline-binding/transport protein containing two subunits of 41 and 34 KDa was identified in Ld. The biosynthetic secretory pathway of soluble-acid phosphatase (S-AcP) was localized in both Ld pro- and amstigotes. S-AcP was purified and the first 30 residues of its N-terminal amino acid sequence determined. Oligonucleotide probes based on this sequence were used to identify and clone the S-AcP gene. The inducible Ld SM 3'- nucleotidase/exo-ribonuclease was isolated, purified and shown to be a 43 kDa mannosylated glycoprotein. Antibodies are being used to screen cDNA-expression libraries to identify and clone its gene. The LD SM 5'-nucleotidase was isolated, purified and shown to be a mannosylated glycoprotein containing two subunits of 72 and 43 kDa. Further, the LD SM glucose transport protein and proton-ATPase were identified and characterized. Based on their homologies with similar proteins in other systems, oligonucleotides of conserved functional regions were synthesized as probes for identifying and cloning the genes for these two leishmanial proteins. The current results provide further functional characterization of parasite SM constituents and these could serve as potential targets for chemotherapy and/or immunodiagnosis/-prophylaxis.