BIOCHEMICAL CYTOLOGY OF HOST-PARASITE INTERACTIONS IN PARASITIC PROTOZOA

利什曼原虫的细胞生物学被作为一种模型进行研究。 以及胞外寄生。重点放在描述 其表面膜(SM)的生化和生理功能 为了确定它们在寄生虫生存和发展中的作用 发展。 利什曼原虫前鞭毛虫具有许多SM运输系统 某些必需氨基酸和核苷的活跃积累。一 其中，一个可能的SM腺苷转运体在L. 使用几种放射性标记的、亲和结合的、交叉标记的多诺瓦尼前星体- 偶联剂。这种外向型SM蛋白具有明显的 目前正在鉴定其分子量为30 kDa。两者都有 分子和免疫化学方法正被用来识别基因 2利什曼L-脯氨酸运输系统编码。利什马尼亚和 两者都能利用S-腺苷-蛋氨酸作为蛋白质 甲基化试剂。在这两种锥虫中都出现了甲基化。 是修改/调节某些SM的活动的机制 原位蛋白质。杜氏乳杆菌前鞭毛体SM3‘-核苷酸酶 纯净到同质。底物专一性，金属阳离子 对这种38 kDa糖蛋白的需求和抑制物进行了表征。 在此过程中发现了三个独立的糖基化事件 利什曼分泌酸性磷酸酶(SACP)的生物合成。这个 其中最后一个包括[PO4-6Galbeta1，4Man]n的高尔基碱加成， SM脂磷脂多糖(LPG)的重复的、构成表位。 液化石油气生物合成的终末阶段也显示在高尔基山脉。 车厢。差减文库的遗传分析正被用于 识别与LPG表达有关的基因。正在对cdna克隆进行测序 目的鉴定SACP基因的全长拷贝。体外培养 无鞭毛体被用作寄生虫基因调控的模型 差异化发展。

The cell biology of Leishmania is investigated as a model of both intra- and extracellular parasitism. Emphasis is placed on characterizing the biochemical and physiological functions of its surface membrane (SM) and secreted components toward defining their roles in parasite survival and development. Leishmania promastigotes possess a number of SM transport systems for the active accumulation of certain essential amino acids and nucleosides. One of these, a putative SM adenosine transporter was identified in situ in L. donovani promastigotes using several radiolabeled, affinity-binding, cross- linking reagents. This externally oriented SM protein has an apparent molecular weight of 30 kDa is currently being characterized. Both molecular and immunochemical approaches are being used to identify genes coding for the 2 leishmanial L-proline transport systems. Leishmania and Crithidia were both shown to use S-adenosyl-methionine as a protein methylating agent. In both of these trypanosomatids, methylation appears to be a mechanism for modifying/regulating the activity of certain SM proteins in situ. The SM 3'-nucleotidase of L. donovani promastigotes was purified to homogeneity. The substrate specificity, metal cation requirements and inhibitors of this 38 kDa glycoprotein were characterized. Three separated glycosylation events were identified during the biosynthesis of the leishmanial secretory acid phosphatase (SAcP). The last of these includes the Golgi-bases addition of [PO4-6Galbeta1,4Man]n, the repetitive, constitutive epitope of the SM lipophosphoglycan (LPG). Terminal stages in LPG biosynthesis were also shown to occur in the Golgi compartment. Genetic analyses of subtractive libraries is being used to identify genes involved in LPG expression. cDNA clones are being sequenced to identify the full length copy of the SAcP gene. In vitro cultivated amastigotes are being used as a model of parasite gene regulated differentiation and development.