TOXOPLASMOSIS--OCULAR INVASION

弓形虫病--眼部侵袭

• 批准号: 3260625
• 负责人: BARBARA A NICHOLS
• 金额: $ 14.56万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 1988-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3260625
• 关键词: Toxoplasma gondii; adenosinetriphosphatase; calcium; cell motility; cytoskeleton; electron microscopy; host organism interaction; ionophores; ocular toxoplasmosis

The applicants have shown that toxoplasma actively invade host cells to establish intracellular residence, and that certain specialized organelles, the conoid and rhoptries, function coordinately during invasion. The conoid is extended, the rhoptries secrete their lytic contents, and the twisting motility of the parasites propels them into the cells. The applicants now plan to study the effects of antibody on these processes to analyze precisely how it functions in host defense to prevent invasion, i.e. which of these several mechanisms operating in cellular penetration are inhibited by antibody. In addition, the applicants plan to examine in greater detail the basic mechanisms involved in motility, conoid extension, and rhoptry secretion. The presence in toxoplasma of a dynein-like ATPase suggests that microtubles may have an active role in cell movement. Consequently, they have designed experiments that reactivate such an ATPase in detergent-extracted toxoplasma to evaluate any resulting change in motility and in the cytoskeleton. In additional experiments, they plan to identify microfilament networks by simultaneous extraction and fixation, followed by negative staining. To determine whether there is an actinmyosin contractile system involved in the movements of toxoplasma, they will attempt to localize actin in glycerinateds toxoplasma with myosin subfragment-1. Inhibitors of microtubules (colchicine and vinblastine) and an inhibitor of microfilaments (cytochalasin D) will be tested for their effects on the motility of toxoplasmas and on their cytoskeleton. The action of the calcium inonphore A23187 on rhoptry secretion will be evaluated to determine whether calcium is requested for secretion, as in many other secretory cells. Dibucaine, which induces synchronous secretion of mucocysts in Tetrahymena, will also be used to stimulate rhoptry secretion in toxoplasma. The disappearance and reappearance of intramembranous "fusion rosettes" will be monitored by freeze-fracture techniques for electron microscopy to analyze the depletion and renewal of secretory organelles following treatment with ionophore and dibucaine.

申请人表明，毒品会积极入侵宿主细胞 建立细胞内居住和某些专门的细胞器 蛋白酶和类托方法在入侵期间协同起作用。 这 蛋白酶延伸，rhoptries分泌其裂解内容，而 扭曲寄生虫的运动能够将它们推入细胞。 这 现在，申请人计划研究抗体对这些过程的影响 精确分析其在宿主防御中的功能以防止入侵， 即在细胞穿透中运行的几种几种机制中的哪种 被抗体抑制。 此外，申请人计划检查 更详细介绍运动性，蛋白酶扩展所涉及的基本机制， 和Rhoptry分泌。 在类似动力蛋白的ATPase的弓形虫中的存在 表明微透明可能在细胞运动中具有积极作用。 因此，他们设计了重新激活这种ATPase的实验 在清洁剂提取的弓形虫中，以评估任何结果的变化 运动性和细胞骨架。 在其他实验中，他们计划 通过同时提取和固定来识别微丝网络， 其次是负染色。 确定是否有一个 参与弓形虫运动的肌动蛋白肌球蛋白收缩系统， 他们将尝试用肌球蛋白将肌动蛋白定位 亚纹理1。 微管抑制剂（秋水仙碱和文素）和 将测试微丝抑制剂（细胞切拉斯蛋白D）的 对弓形虫及其细胞骨架的运动的影响。 这 钙INOPHORE A23187在Rhoptry分泌上的作用将是 评估以确定是否要求钙进行分泌，如 许多其他分泌细胞。 Dibucaine，诱导同步分泌 四氢菌中的粘蛋白剂也将用于刺激步骤 弓形虫的分泌。 失踪和重新出现 膜内“融合玫瑰花结”将通过冻结骨折监测 电子显微镜的技术分析了耗竭和更新 用离子载体和二氨摄氏菌治疗后分泌细胞器。