Structure & function of bacterial adhesion pili

结构

• 批准号: 7477492
• 负责人: ESTHER BULLITT
• 金额: $ 34.45万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7477492
• 关键词: 3-Dimensional; Address; Adherence; Adhesions; Bacteria; Bacterial Adhesins; Bacterial Adhesion; Binding; Biochemical; Cartoons; Cells; Child; Computer Simulation; Condition; Cryoelectron Microscopy; Data; Depth; Diarrhea; Disease Outbreaks; Electron Microscopy; Escherichia coli; Excision; Filament; Fimbriae Proteins; Food; Freezing; Furuncles; Gel; Genetic Programming; Glycerol; Goals; Haemophilus influenzae; Haemophilus influenzae type b bacteria; Health; Homology Modeling; Human; Ice; Immunoelectron Microscopy; Individual; Infant; Infection; International; Intestines; Kidney; Lead; Length; Liquid substance; Localized; Measures; Mechanics; Minor; Modeling; N-terminal; Optics; Physiological; Pilum; Predisposition; Prevention therapy; Proteins; Range; Rate; Recovery; Research; Research Personnel; Resolution; Risk; Role; Sampling; Site-Directed Mutagenesis; Sodium Dodecyl Sulfate-PAGE; Source; Specificity; Staining method; Stains; Structure; Study models; Surface; System; Testing; Therapeutic; Time; Tissues; Urinary tract infection; Uropathogenic E. coli; Variant; Virulence Factors; Virulent; Water; base; cell motility; design; enterotoxigenic Escherichia coli; image processing; improved; laser tweezer; optical traps; pathogenic bacteria; prevent; programs; reconstruction; repaired; research study; stem; sugar; three dimensional structure

DESCRIPTION (provided by applicant): Survival of pathogenic bacteria in their host is correlated with their capacity to maintain attachment to host tissue. Often this adherence is facilitated by the presence of filamentous adhesion pili on the bacterial surface, as in ETEC (enterotoxigenic Escherichia coli). ETEC cause severe diarrhea, presenting a significant worldwide health risk, particularly for infants and small children. In addition, the ease with which ETEC-caused diarrhea spreads via tainted food or water, places international travelers at high risk when entering regions where infection is endemic. In order to prevent or limit outbreaks, it is vital that we understand the mechanism of sustained bacterial attachment that can lead to colonization and illness. Structural information about adhesion pili will provide a basis for rational design of new therapies for prevention of bacterial binding or for removal of pathogenic bacteria already bound to the human host. The long-term goal of this project is to elucidate how the structure of pili supports their role as a virulence factor for pathogenic bacteria. In the proposed project period, studies on the structure and function of ETEC pili, in-depth computer modeling of P-pili expressed on the surface of pyelonephritic Escherichia coli (which cause urinary tract infections involving the kidneys), pilus damage/recovery experiments, and localization of type 1 adhesins will be used to examine the relationship between the structure and the function of adhesion pili. A combined approach will be employed to 1) elucidate the structural features of virulent ETEC pili that enable them to withstand peristaltic motility and other intestinal cleansing systems. Studies will include electron microscopy and image processing of negatively stained and frozen-hydrated ETEC pili. 2) examine the mechanism by which the P-pilus helical filament can unwind to a thin fibrillar structure five times its original length. Energy minimization and spatial constraints will be used with genetic algorithms to model, from individual monomeric subunits, this prototypic pilus filament into both intact and damaged pili. 3) investigate a means for reducing bacterial binding through damage to pili, with the aim of reducing the bacterial load and thus permitting the body's natural defenses to eradicate the remainder. Studies will use optical tweezers to measure the forces necessary to damage P-pili expressed on uropathogenic bacteria, and to investigate whether recovery occurs. 4) localize the adhesins on type 1 pili using immunoelectron microscopy.

描述（由申请人提供）：病原菌在宿主中的存活与其维持宿主组织附着的能力相关。通常，这种粘附是由于细菌表面丝状粘附菌毛的存在而促进的，如 ETEC（产肠毒素大肠杆菌）。 ETEC 会导致严重腹泻，对全球健康构成重大风险，特别是对于婴儿和幼儿。此外，ETEC 引起的腹泻很容易通过受污染的食物或水传播，使国际旅行者在进入感染流行地区时面临高风险。为了预防或限制疫情爆发，我们必须了解可导致定植和疾病的持续细菌附着机制。 有关粘附菌毛的结构信息将为合理设计新疗法提供基础，以防止细菌结合或去除已与人类宿主结合的病原菌。该项目的长期目标是阐明菌毛的结构如何支持其作为病原菌毒力因子的作用。在拟议项目期间，研究ETEC菌毛的结构和功能，对肾盂肾炎大肠杆菌（引起肾脏尿路感染）表面表达的P-菌毛进行深入的计算机建模，菌毛损伤/恢复实验， 1型粘附素的定位将用于检查粘附菌毛的结构和功能之间的关系。将采用综合方法来 1) 阐明有毒 ETEC 菌毛的结构特征，使其能够承受蠕动和其他肠道清洁系统。研究将包括负染色和冷冻水合 ETEC 菌毛的电子显微镜和图像处理。 2）研究P-菌毛螺旋丝可以展开成其原始长度五倍的细纤维结构的机制。能量最小化和空间约束将与遗传算法一起使用，从单个单体亚基将这种原型菌毛丝建模为完整和受损的菌毛。 3）研究一种通过损伤菌毛来减少细菌结合的方法，目的是减少细菌负荷，从而使身体的自然防御能力消除剩余细菌。研究将使用光镊来测量破坏尿路致病细菌上表达的 P-菌毛所需的力，并调查是否会恢复。 4) 使用免疫电子显微镜将粘附素定位在 1 型菌毛上。