Polysaccharide capsule export in the fungal pathogen Cryptococcus neoformans

真菌病原体新型隐球菌中的多糖胶囊输出

• 批准号: 7239830
• 负责人: Tamara L Doering
• 金额: $ 22.18万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-20 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7239830
• 关键词: Acquired Immunodeficiency Syndrome; Address; Anabolism; Area; Basic Science; Biochemical; Biological; Biological Assay; Biological Models; Biology; Carbohydrates; Cell Fractionation; Cell Wall; Cell surface; Cells; Cellular biology; Chromatography; Condition; Cryptococcus; Cryptococcus neoformans; Disease; Electrons; Engineering; Enzymes; Goals; Human; Immunocompromised Host; Individual; Infection; Investigation; Knowledge; Left; Life; Methods; Microbe; Nature; Organism; Pathogenesis; Polysaccharides; Precipitation; Process; Public Health; Research; Route; Secretory Vesicles; Structure; Surface; Travel; Vesicle; Virulence Factors; Work; abstracting; analytical method; capsule; design; experience; fascinate; fungus; mutant; novel strategies; pathogen; research study; size

DESCRIPTION (provided by applicant): Polysaccharide Capsule Export in the Fungal Pathogen Cryptococcus neoformans ABSTRACT Cryptococcus neoformans is an opportunistic pathogen, responsible for life-threatening disease in individuals who are immunocompromised due to AIDS or other conditions. The main virulence factor of Cryptococcus is an extensive polysaccharide capsule that surrounds its cell wall. This capsule is required for the fungus to cause disease. Little information is available about the intracellular formation of capsule components, and none about how they exit the cell and become associated with its surface. In this R21 application we propose to develop new approaches to exploration of these fundamental questions, using cell biological methods that have not yet been applied to C. neoformans. Specifically, we propose to directly investigate the nature of intracellular capsular material, taking advantage of a mutant strain we have engineered to accumulate secretory vesicles containing capsule- related polysaccharides. Aim I proposes to develop methods to purify and characterize the secretory vesicles that contain capsule precursors. Aim II proposes to isolate capsule-related polysaccharides from these vesicles, purify them, and apply analytical methods to define their glycan structures. Depending on the specific nature of the capsule precursors, the experiments may begin to address the presence of any non-carbohydrate components associated with the relevant glycans. The approaches that will be used to achieve these goals include subcellular fractionation, electron micros- copy, biochemical enzyme assays, immuno-detection, differential extraction and precipitation, a variety of chromatography methods, and glycan analysis. These exploratory studies will have a major impact on the field, as they will address a critical gap in our understanding of this organism's major virulence factor, break new ground in the methods available for study of C. neoformans, and open exciting areas for investigation of this important pathogen. / RELEVANCE This research is highly relevant to public health because the organism being investigated causes serious human illness, for which current therapies are not adequate. The process to be studied is fundamental to the ability of Cryptococcus neoformans to cause disease, so understanding and inhibiting it may advance treatment of cryptococcal infection. Further, this work will contribute to basic science knowledge, which will impact the area of pathogenic microbes as well as other areas of biology.

摘要新型隐球菌是一种机会性病原体，可导致因艾滋病或其他疾病而免疫功能低下的个体罹患危及生命的疾病。隐球菌的主要毒力因子是围绕其细胞壁的广泛的多糖胶囊。这种胶囊是真菌致病所必需的。关于包膜成分在细胞内形成的信息很少，关于它们如何离开细胞并与细胞表面联系的信息也很少。在这个R21应用程序中，我们建议开发新的方法来探索这些基本问题，使用尚未应用于新生c的细胞生物学方法。具体来说，我们建议直接研究细胞内荚膜物质的性质，利用我们设计的一种突变菌株来积累含有荚膜相关多糖的分泌囊泡。目的：建立含胶囊前体的分泌囊泡的纯化和表征方法。Aim II建议从这些囊泡中分离胶囊相关多糖，纯化它们，并应用分析方法确定它们的聚糖结构。根据胶囊前体的具体性质，实验可以开始处理与相关聚糖相关的任何非碳水化合物组分的存在。将用于实现这些目标的方法包括亚细胞分离、电子显微镜复制、生化酶测定、免疫检测、差分提取和沉淀、各种色谱方法和聚糖分析。这些探索性研究将对该领域产生重大影响，因为它们将解决我们对该生物主要毒力因子的理解中的关键空白，为研究新形态C.开辟新的方法，并为研究这一重要病原体开辟令人兴奋的领域。这项研究与公共卫生高度相关，因为所调查的生物体会导致严重的人类疾病，而目前的治疗方法尚不充分。所研究的这一过程是新型隐球菌致病能力的基础，因此了解和抑制这一过程可能会促进隐球菌感染的治疗。此外，这项工作将有助于基础科学知识，这将影响病原微生物领域以及生物学的其他领域。