Biosynthesis and regulation of a unipolar polysaccharide in Agrobacterium

农杆菌中单极性多糖的生物合成和调控

• 批准号: 9384094
• 负责人: WILLIAM C FUQUA
• 金额: $ 36.44万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-08 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9384094
• 关键词: Acids; Adhesions; Adhesives; Affect; Agriculture; Agrobacterium; Alphaproteobacteria; Anabolism; Anti-Bacterial Agents; Automobile Driving; Bacteria; Bacterial Adhesins; Bacterial Infections; Bacterial Model; Biochemical; Biocompatible Materials; Biogenesis; Biological; Biomedical Engineering; Biosynthetic Proteins; Caulobacter; Caulobacter crescentus; Cell physiology; Cell surface; Cells; Chemicals; Chronic; Collection; Communities; Complex; Dependence; Development; Disease; Environment; Environmental Risk Factor; Evaluation; Genes; Genetic; Genetic Screening; Genomics; Growth; Individual; Industrialization; Infection; Lead; Lectin; Mediating; Medical; Medical Device; Microbial Biofilms; Modeling; Monosaccharides; Pathway interactions; Pattern; Periodicity; Phenotype; Physiological; Polysaccharides; Process; Production; Property; Proteins; Pterins; Regulation; Rhizobium radiobacter; Role; Second Messenger Systems; Signal Pathway; Signal Transduction; Specificity; Structure; Surface; Swimming; System; Technology; Variant; antimicrobial; base; cell motility; cellular development; experimental study; imaging approach; improved; insight; medical implant; member; microscopic imaging; mutant; novel; pathogen; periplasm; phosphoric diester hydrolase; prevent; response; retinal rods; spatial relationship

PROJECT SUMMARY The establishment of productive, stable surface interactions is an important process for bacteria, that can lead to formation of the adherent communities known as biofilms. These assemblages are challenges in agricultural, industrial and medical settings, and are intrinsically tolerant to many antimicrobial therapies. For a number of bacteria in the large and diverse Alphaproteobacteria (APB) group, attachment to surfaces and to other cells requires production of a structure comprised of polysaccharide localized to a single cellular pole. In the model pathogen Agrobacterium tumefaciens this structure is called the unipolar polysaccharide (UPP). Polar adhesins similar to the UPP are widespread among the APB, including other pathogens and symbionts, and the A. tumefaciens UPP is therefore a representative model for these diverse bacteria. Among these, the stalked bacterium Caulobacter crescentus produces a similar structure called the holdfast at the stalk tip, and although it has been well studied, remains poorly understood and is less broadly representative than the UPP. These polar polysaccharides can drive stable surface attachment and host interactions. In A. tumefaciens the UPP is comprised of at least two distinct polysaccharide species, and the genes required for synthesis suggest that there may be overlapping biosynthesis pathways. We aim to determine how A. tumefaciens coordinates and regulates production of these polysaccharides during surface colonization, including dynamic localization of the biosynthetic complexes. Production of the A. tumefaciens UPP is strictly regulated by contact with the surface, and cells rarely if ever produce the UPP when free-swimming. The proposed studies will dramatically improve our current understanding of UPP properties and biosynthesis, and will elucidate its regulation via a network of intracellular signal cascades, its surface-dependent polar localization, and other environmental signals that affect its production, and thereby attachment. At the core of this control network is the ubiquitous bacterial second messenger cyclic diguanylate monophosphate, which regulates UPP production. Among the primary UPP regulatory mechanisms are a novel signaling pathway involving small metabolites called pterins, and the response to low pH. The project utilizes an extensive collection of genetic mutants and variants, quantitative microscopic imaging approaches, genomic technology, and sophisticated biochemical approaches to illuminate the cellular processes that promote attachment via the UPP. The findings generated will contribute to the understanding of the motile to sessile transition and initiation of biofilm formation. We will characterize the biosynthesis of a novel biological adhesive(s) and a potential antimicrobial target, and will reveal how bacterial cells control production of these important products to promote surface interactions that lead to biofilm formation. Our findings will provide fundamental information about these polar adhesins, identifying new targets for anti-bacterial approaches and facilitating development of new biomaterials.

项目总结 建立高效、稳定的表面相互作用对细菌来说是一个重要的过程，即 会导致附着群落的形成，这种群落被称为生物膜。这些集合是对 农业、工业和医疗环境，对许多抗菌疗法具有内在的耐受性。为. 大型和多样化的甲型变形杆菌(APB)组中的细菌数量，附着在表面和 其他细胞需要生产一种由定位于单个细胞极点的多糖组成的结构。在……里面 模式致病菌根癌农杆菌的这种结构被称为单极多糖(UPP)。 与UPP类似的极地粘附素在APB中广泛存在，包括其他病原体和共生体， 因此，根癌农杆菌UPP是这些不同细菌的代表性模型。其中， 柄细菌新月形杆菌在茎尖端产生一种类似的结构，称为持持器，以及 尽管它已经得到了很好的研究，但仍然缺乏了解，而且没有UPP那么广泛的代表性。 这些极性多糖可以驱动稳定的表面附着和宿主相互作用。在根癌农杆菌中 UPP至少由两种不同的多糖组成，合成所需的基因表明 可能存在重叠的生物合成途径。我们的目标是确定根癌农杆菌是如何协调 并在表面定植期间调节这些多糖的产生，包括动态定位 生物合成的复合体。根癌农杆菌UPP的生产受到严格的监管，通过接触 在自由游泳时，细胞几乎不会产生UPP。拟议的研究将极大地 改善我们目前对UPP特性和生物合成的理解，并将通过一种 细胞内信号级联网络、依赖于表面的极点定位以及其他环境 影响其生产的信号，从而影响其依附。这个控制网络的核心是无处不在的 细菌第二信使环二鸟苷一磷酸，它调节UPP的产生。在这些人中 主要的UPP调节机制是一种新的信号通路，涉及称为蝶呤的小代谢物， 对低pH的反应。该项目利用了大量的基因突变和变种， 定量显微成像方法、基因组技术和复杂的生化方法 以阐明通过UPP促进依恋的细胞过程。所产生的发现将有助于 有助于理解动生向固位的转变和生物膜形成的启动。我们将描述 一种新型生物粘合剂(S)的生物合成和潜在的抗菌靶标，并将揭示如何 细菌细胞控制这些重要产物的产生，以促进表面相互作用，从而导致生物被膜 队形。我们的发现将提供有关这些极地粘附素的基本信息，识别新的 抗菌方法的目标和促进新生物材料的开发。