Development of a novel multipurpose model to propagate and study the tick transmission cycle of relapsing fever spirochetes from Eurasia.

开发一种新型多用途模型，用于繁殖和研究欧亚大陆回归热螺旋体的蜱传播周期。

• 批准号: 10651550
• 负责人: Job E Lopez
• 金额: $ 20.06万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-05 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10651550
• 关键词: Address; Asia; Bacteria; Bacterial Genome; Blood; Borrelia; Child; Chromosomes; Climate; Comparative Genomic Analysis; Complex; Country; Data; Development; Disease; Gene Rearrangement; Genes; Genetic Recombination; Genome; Genome Stability; Genomics; Goals; Growth; Health; In Vitro; Knowledge; Life Cycle Stages; Literature; Longevity; Maintenance; Mammals; Middle East; Modeling; Molecular; Molecular Probes; Morbidity - disease rate; Natural Source; Order Spirochaetales; Ornithodoros; Pathogenesis; Phylogenetic Analysis; Plasmids; Politics; Positioning Attribute; Public Health; Publications; Publishing; Relapsing Fever; Replicon; Reporting; Research; Resource-limited setting; Resources; Southern Blotting; System; Testing; Ticks; Time; Ukraine; chicken egg; cost effective; egg; epidemiology study; genome annotation; genome resource; genomic tools; improved; low income country; model development; mortality; neglect; novel; pathogen; pathogen genomics; poor communities; relapsing fever borrelia; tick bite; tick transmission; transmission process; vector; vector competence; vector tick; vector-borne pathogen

Project Summary Relapsing fever (RF) spirochetes are a group of neglected vector-borne pathogens that are a significant cause of child morbidity and mortality. The current approaches to grow and assess tick transmission of RF spirochetes are impractical in resource limited settings where they are prevalent. For example, propagating spirochetes in culture medium is expensive and labor intensive. Moreover, prolonged in vitro propagation in medium causes DNA rearrangements of their already exceedingly complex genomes, and this results in diminished vector colonization and pathogenesis. There is a critical need for cost effective practical approaches to grow and study RF spirochetes from neglected regions of the globe. This project builds on our prior our publication reporting the first isolation of Borrelia caucasica, which is part of the Persica species complex and is distributed through Eurasia and the Middle East. Moreover, our recent advances RF spirochete genomics addressed a major limitation in the field and resulted in complete chromosome and plasmid assembled and annotated genomes. The genomics tools we developed can now be utilized to characterize a model for the Persica complex species. Interestingly, historical literature suggested that embryonated chicken eggs (ECEs) could be infected with RF spirochetes by tick bite and the bacteria grew in this system. However, at the time molecular and genomics resources were not available to characterize this model and knowledge gaps remain about the pathogens genomic stability in ECEs. Leveraging recent advances in RF spirochete genomics, the ECE model can now be fully developed to study Persica complex species. In this study, two aims are proposed. The first aim is to utilize genomics resources for RF spirochetes and evaluate plasmid diversity and identify unique plasmid markers of B. caucasica isolates through a comparative genomic analysis. The first objective is to complete reference quality genomes assemblies of B. caucasica isolates and perform a comparative genomics analysis to identify plasmid markers. The second objective is to develop a panel of specific probes needed to evaluate plasmid retention and rearrangements during the B. caucasica life cycle. In the second aim, we will assess genomic changes of B. caucasica using the tick – ECE model. The first objective is to develop the B. caucasica model in ECEs and evaluate spirochete growth, tick acquisition, and subsequent tick transmission of spirochetes to naïve eggs. The second objective is to assess plasmid stability and the ability of B. caucasica to remain infectious after passage through ECEs. The establishment of the ECE model will result in a cost-effective approach to amplify RF spirochetes in the absence of culture medium. Moreover, the development of this model offers a practical system to study the transmission cycle and vector competence of RF spirochetes in resource limited settings. With the emergence and health burden of RF spirochetes in low-income countries, it is important to develop systems to propagate and study these neglected pathogens.

项目摘要 复发热(RF)螺旋体是一组被忽视的媒介传播病原体，是一个重要的原因 儿童发病率和死亡率。当前培养和评估RF螺旋体扁虱传播的方法 在它们普遍存在的资源有限的环境中是不切实际的。例如，在人体内繁殖螺旋体 培养基价高，劳动强度大。此外，在培养基中延长试管繁殖时间也会导致 他们已经非常复杂的基因组的DNA重排，这导致载体减少 定植和发病机制。迫切需要具有成本效益的实用方法来发展和研究 来自全球被忽视地区的RF螺旋体。这个项目建立在我们之前的出版物上，报道了 首次分离到高加索疏螺旋体，它是桃属物种复合体的一部分，通过 欧亚大陆和中东。此外，我们的最新进展RF螺旋体基因组学解决了一个主要的 限制在田间，并导致完整的染色体和质粒组装和注释的基因组。 我们开发的基因组学工具现在可以用来描述桃属复杂物种的模型。 有趣的是，历史文献表明鸡胚化的鸡蛋(ECEs)可以感染RF。 被扁虱叮咬的螺旋体和细菌在这个系统中生长。然而，在当时，分子和基因组学 没有资源来描述这种模式，关于病原体的知识差距仍然存在 ECEs的基因组稳定性。利用RF螺旋体基因组学的最新进展，欧洲经委会模型现在可以 为研究桃属复杂物种而全面发展。在本研究中，我们提出了两个目标。第一个目标是利用 RF螺旋体的基因组学资源和评估质粒多样性并确定独特的质粒标记 高加索芽孢杆菌通过比较基因组分析分离。第一个目标是完成参考质量 高加索芽胞杆菌分离株基因组组装及比较基因组学分析鉴定质粒 记号笔。第二个目标是开发一组需要的特定探针来评估质粒保留和 高加索球藻生活史中的重新安排。在第二个目标中，我们将评估B. 高加索地区使用TICK-欧洲经委会模型。第一个目标是在ECEs和ECEs中发展高加索杆菌模型 评估螺旋体的生长，扁虱的获取，以及随后螺旋体向幼虫卵的传播。这个 第二个目标是评估质粒的稳定性和高加索芽胞杆菌在传代后保持感染的能力。 通过ECES。欧洲经委会模式的建立将产生一种具有成本效益的方法来放大射频 螺旋体在没有培养液的情况下。此外，该模型的开发还提供了一个实用的系统 研究资源受限环境下RF螺旋体的传播周期和媒介能力。与 在低收入国家，RF螺旋体的出现和健康负担，重要的是开发系统，以 繁殖和研究这些被忽视的病原体。