BIOLOGY OF GIARDIA--ROLE OF CARBOHYDRATE RESIDUES

贾第鞭毛虫生物学——碳水化合物残基的作用

• 批准号: 3454930
• 负责人: Honorine D Ward
• 金额: $ 10.53万
• 依托单位: TUFTS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-08-01 至 1995-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3454930
• 关键词: Giardia; N acetylgalactosamine; autoradiography; carbohydrate biosynthesis; carbohydrate structure; cell differentiation; chitin; developmental genetics; disease /disorder prevention /control; electron microscopy; enzyme structure; gas chromatography mass spectrometry; gel electrophoresis; gel filtration chromatography; gene expression; giardiasis; high performance liquid chromatography; human subject; immunoprecipitation; intracellular parasitism; laboratory mouse; ligase; microorganism genetics; molecular genetics; monoclonal antibody; protein biosynthesis; protein purification; protein structure function; protozoal cyst

Giardia lamblia is a significant cause of diarrheal disease worldwide which is perpetuated by the infective cyst form of the parasite. The mechanisms underlying the process of differentiation from trophozoite to cyst are poorly understood. The overall purpose of this project is to decipher the biochemical and molecular events involved in this process, focusing on structure and function of carbohydrate moieties in both trophozoite and cyst. The specific aims of this proposal are directed at a) elucidating structural and biosynthetic aspects of N-acetyl-glucosamine containing carbohydrate moieties which have been identified as chitin in cyst walls as well as linked to glycoproteins in trophozoites and cysts and b) relating these aspects to the biological role of these moieties in differentiation of the parasite. The first aim is to determine the structure and linkage of the GIcNAc residues in trophozoite and cyst glycoproteins with the long term objective of studying their biosynthesis and ascertaining whether they serve as precursor moieties for chitin synthesis which is a key event in differentiation. The second aim is to characterize, purify and produce antibodies to chitin synthase which is a developmentally regulated enzyme involved in the biosynthesis of chitin. These studies will facilitate the long term objective of delineating genetic control of differentiation at the molecular level by identifying cyst and trophozoite specific genes encoding developmentally regulated proteins. The third aim is to determine the subcellular localization of chitin and chitin precursors as well as the N-acetyl-glucosamine containing glycoproteins at the ultrastructural level. The last aim is to relate the findings obtained at the structural and biochemical level to growth and differentiation of the parasite in vitro as well as in vivo in animal models of giardiasis. The ultimate goal is to design strategies to arrest differentiation, interrupt the life cycle of the parasite and control spread of the disease.

贾第鞭毛虫是世界范围内腹泻病的一个重要原因， 由寄生虫的感染性囊肿形式永久存在。机制 从滋养体到囊肿分化过程的基础是 不太了解。该项目的总体目的是破译 该过程涉及的生化和分子事件，重点关注 滋养体和滋养体中碳水化合物部分的结构和功能 囊肿。 该提案的具体目标是 a) 阐明 含 N-乙酰氨基葡萄糖的结构和生物合成方面 已被鉴定为囊壁中的几丁质的碳水化合物部分 以及与滋养体和包囊中的糖蛋白相关，b) 相关 这些部分在分化中的生物学作用的这些方面 寄生虫。第一个目标是确定结构和联系 滋养体和囊肿糖蛋白中的 GlcNAc 残基具有长 研究它们的生物合成并确定它们是否 作为甲壳素合成的前体部分，这是甲壳素合成的关键事件 差异化。第二个目标是表征、纯化和生产 几丁质合酶的抗体，这是一种发育调节酶 参与甲壳质的生物合成。这些研究将有助于 描绘分化的遗传控制的长期目标 通过识别囊肿和滋养体特异性基因在分子水平上 编码发育调节蛋白。第三个目标是确定 几丁质和几丁质前体的亚细胞定位以及 超微结构水平上含有 N-乙酰氨基葡萄糖的糖蛋白。 最后一个目标是将在结构和结构方面获得的发现联系起来 生化水平对寄生虫体外生长和分化的影响 以及贾第鞭毛虫病动物模型的体内。最终目标是 设计策略来阻止分化，中断生命周期 寄生虫并控制疾病的传播。