Synthesis and properties of a bacterial bioadhesive

细菌生物粘附剂的合成及性能

• 批准号: 8518406
• 负责人: YVES V BRUN
• 金额: $ 34.55万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8518406
• 关键词: Adherence; Adhesions; Adhesiveness; Adhesives; Age; Aging; Antitoxins; Apoptosis; Area; Atomic Force Microscopy; Bacteria; Bacterial Infections; Base Sequence; Binding; Biochemical; Biocompatible Materials; Biological; Biological Process; Biophysics; Caulobacter; Caulobacter crescentus; Cell Death; Cells; Chemicals; DNA; DNA Binding; DNA Sequence; Data; Deacetylase; Deacetylation; Dental; Development; Employee Strikes; Environment; Exhibits; Fluorescence Microscopy; Fresh Water; Future; Genes; Genetic; Goals; Human Activities; Human body; Image; Infection; Ionic Strengths; Kinetics; Marines; Measures; Mechanics; Medical; Methods; Microbial Biofilms; Mutation; Operative Surgical Procedures; Oxygen; Polysaccharides; Production; Property; Research; Resolution; Role; Saline; Solutions; Solvents; Specificity; Spectrum Analysis; Structure; Surface; System; Testing; Toxin; base; crosslink; design; extracellular; improved; inhibitor/antagonist; insight; interdisciplinary approach; mutant; pathogen; physical property; polysaccharide deacetylase; research study; response; shear stress

DESCRIPTION (provided by applicant): Bacteria often utilize polysaccharides as adhesive structures to attach to surfaces, to form biofilms, and to infect host cells. In addition, polysaccharides hold strong promise as biological adhesives in many areas of human activity, including as dental and surgical adhesives. The bacterium Caulobacter crescentus synthesizes a polysaccharide called the holdfast that exhibits and impressive adhesive force. Contrary to most commercial adhesives, holdfasts adhere tightly to a variety of surfaces in both freshwater and marine environments. Such a property is critical for medical applications in the human body. The general goal of this research is to use a multidisciplinary approach ranging from genetics to biophysics to study the chemical and biophysical basis for holdfast properties and to understand how holdfast properties are modulated by deacetylation and inhibition by extracellular DNA (eDNA). The project has three specific aims. The first aim is to determine the biophysical basis for holdfast adhesiveness. Atomic force microscopy (AFM) will be used to systematically study the influence of surface roughness, shear stress, surface composition, ionic strength, and pH on holdfast adhesion in order to provide a better understanding of the mechanism of holdfast adhesion and adhesion control. The second aim is to determine the role of deacetylation in holdfast anchoring and adhesive properties. A holdfast polysaccharide deacetylase mutant causes the release of non-adherent holdfast in solution. The composition and structure of the holdfast polysaccharide will be determined from normal and deacetylase mutant cells. AFM force spectroscopy and high-resolution fluorescence microscopy will be used to determine the role of deacetylation on holdfast adhesiveness and cohesiveness. Biochemical experiments will be used to study the role of deacetylation in anchoring the holdfast to the cell. Finally, similar studies of the holdfast of marine species will provide better biomaterials for potential applications in the saline environment of the human body. The third aim is to determine the biological basis for the recently discovered mechanism of eDNA inhibition of holdfast adherence. The role of a toxin-antitoxin system in the production of eDNA by programmed cell death will be studied and the basis for the sequence specificity of holdfast inhibition will be determined. AFM indentation studies and simultaneous AFM imaging and Raman scattering spectroscopy of holdfasts bound or not to eDNA will be used to determine how specific DNA alters the structure and structural properties of the holdfast. Results from the proposed studies will provide insight into the basic mechanisms for the impressive adhesive properties of the holdfast and modulation of these properties, paving the way for the future development of the holdfast as a biological adhesive. In addition, results of these studies will provide insights into the mechanism of polysaccharide adhesiveness in general, as well as for strategies to inhibit polysaccharide adhesion, for example during infection by pathogens.

描述（由申请人提供）：细菌经常利用多糖作为粘附结构来附着到表面、形成生物膜并感染宿主细胞。此外，多糖在人类活动的许多领域中作为生物粘合剂具有广阔的前景，包括作为牙科和外科粘合剂。新月柄杆菌合成一种称为固着剂的多糖，具有令人印象深刻的粘附力。与大多数商业粘合剂相反，固定器可以在淡水和海洋环境中紧密粘附到各种表面。这种特性对于人体的医学应用至关重要。这项研究的总体目标是利用从遗传学到生物物理学的多学科方法来研究固着特性的化学和生物物理基础，并了解固着特性如何通过细胞外 DNA (eDNA) 的脱乙酰化和抑制来调节。该项目有三个具体目标。第一个目标是确定固着力的生物物理基础。原子力显微镜（AFM）将用于系统研究表面粗糙度、剪切应力、表面成分、离子强度和pH值对固着力附着力的影响，以便更好地理解固着力附着力和附着力控制的机制。第二个目的是确定脱乙酰化在固着锚定和粘合性能中的作用。固着剂多糖脱乙酰酶突变体导致溶液中非粘附固着剂的释放。固着多糖的组成和结构将从正常细胞和脱乙酰酶突变细胞中确定。 AFM 力谱和高分辨率荧光显微镜将用于确定脱乙酰化对固着力和内聚力的作用。生化实验将用于研究脱乙酰化在将固着物锚定到细胞中的作用。最后，对海洋物种的固着物的类似研究将为人体盐分环境中的潜在应用提供更好的生物材料。第三个目标是确定最近发现的 eDNA 抑制固着粘附机制的生物学基础。将研究毒素-抗毒素系统在程序性细胞死亡产生 eDNA 中的作用，并确定 Holdfast 抑制的序列特异性的基础。结合或未结合 eDNA 的固着物的 AFM 压痕研究以及同步 AFM 成像和拉曼散射光谱将用于确定特定 DNA 如何改变固着物的结构和结构特性。拟议研究的结果将深入了解固着器令人印象深刻的粘合性能的基本机制以及这些性能的调节，为固着器作为生物粘合剂的未来发展铺平道路。此外，这些研究的结果将提供以下见解： 多糖粘附的一般机制，以及抑制多糖粘附的策略，例如在病原体感染期间。