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

基本信息

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
项目类别：
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

项目摘要

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.

项目摘要建立生产性稳定的表面相互作用是细菌的重要过程，可以导致形成被称为生物膜的粘附社区。这些组合是挑战农业，工业和医疗环境，对许多抗菌疗法具有本质上的耐受性。对于大型和多样的字母摩菌病（APB）组中的细菌数量，附着在表面上，对其他细胞需要生产由位于单个细胞极的多糖组成的结构。在模型病原体农杆菌Tumefaciens这种结构称为单极多糖（UPP）。与UPP相似的极性粘附素在APB中广泛存在，包括其他病原体和共生体，因此，A. tumefaciens UPP是这些不同细菌的代表性模型。其中，茎细菌花椰菜牙齿牙齿牙齿菌会产生一个类似的结构，称为茎尖的Holdfast，并且尽管对其进行了充分的研究，但仍然了解得很糟糕，并且不如UPP广泛代表。这些极性多糖可以驱动稳定的表面附件和宿主相互作用。在A. Tumefaciens中 UPP由至少两种不同的多糖物种组成，合成所需的基因表明可能存在重叠的生物合成途径。我们旨在确定A. tumefaciens如何坐标并调节表面定植期间这些多糖的产生，包括动态定位生物合成复合物的。 A. tumefaciens upp的生产严格通过与自由速度时，表面和细胞很少会产生UPP。拟议的研究将极大地提高我们目前对UPP特性和生物合成的理解，并将通过A阐明其调节细胞内信号级联的网络，其表面依赖性极性定位和其他环境影响其生产的信号，从而依恋。该控制网络的核心是无处不在的细菌第二信使循环二甘氨酸单磷酸盐，可调节UPP的产生。在原发性UPP调节机制是一种新型的信号通路，涉及称为翼龙的小型代谢物以及对低pH的反应。该项目利用广泛的遗传突变体和变体集合，定量微观成像方法，基因组技术和先进的生化方法阐明通过UPP促进附着的细胞过程。产生的发现将做出贡献理解动向对梗死的生物膜形成的启动和启动。我们将表征新型生物学粘合剂和潜在抗菌靶的生物合成，并将揭示如何细菌细胞控制这些重要产物的生产，以促进导致生物膜的表面相互作用形成。我们的发现将提供有关这些极性粘合剂的基本信息，并确定新的抗菌方法的目标，并促进新生物材料的发展。