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载体传播病原体，是一个重要原因 儿童发病率和死亡率。当前的生长和评估RF螺旋体传播的方法 在有限的设置中，不切实际，在这些设置中很普遍。例如，在 培养基是昂贵且劳动密集型的。此外，在培养基原因中延长体外繁殖 它们已经非常复杂的基因组的DNA重排，这导致矢量减少 定植和发病机理。迫切需要采用成本有效的实用方法来发展和学习 来自全球被忽视地区的RF螺旋体。该项目以我们先前的出版物报告为基础 伯罗利高加西省的第一个隔离，这是Persica物种复合物的一部分，并通过 欧亚大陆和中东。此外，我们最近的进步RF Spirochete基因组学解决了一个主要 该田间的限制，导致组装和注释基因组的完整染色体和质粒。 我们开发的基因组学工具现在可以用来表征Persica复杂物种的模型。 有趣的是，历史文献表明胚胎鸡蛋（ECE）可以被RF感染 tick咬的螺旋体和细菌在该系统中生长。但是，当时分子和基因组学 资源无法表征此模型，并且知识差距仍然存在于病原体上 ECES中的基因组稳定性。利用RF Spirochete基因组学的最新进展，ECE模型现在可以 完全开发用于研究Persica复杂物种。在这项研究中，提出了两个目标。第一个目的是利用 RF螺旋体的基因组资源并评估质粒多样性并确定独特的质粒标记 B.通过比较基因组分析分离的高加索分离株。第一个目标是完成参考质量 芽孢杆菌分离株的基因组组件并进行比较基因组学分析以鉴定质粒 标记。第二个目标是开发一组评估质粒保留所需的特定问题和 B.多古西卡生命周期期间的重排。在第二个目标中，我们将评估B的基因组变化。 使用TICK - ECE型号的高加西亚。第一个目的是在ECES中开发B. Cucasica模型，并 评估螺旋体的生长，tick的获取以及随后将螺旋体传播到幼稚的卵。 第二个目标是评估质粒稳定性和通过后的高芽孢杆菌在通过后保持感染力的能力 通过Eces。 ECE模型的建立将导致一种具有成本效益的方法来扩大RF 在没有培养基的情况下，螺旋体。此外，该模型的开发提供了一个实用的系统 研究RF螺旋体在资源有限设置中的传输周期和矢量能力。与 RF螺旋体在低收入国家的出现和健康伯恩，开发系统很重要 传播并研究这些被忽视的病原体。