Identifying Borrelia turicatae genes needed for colonization and transmission fro

描述(申请人提供)：复发性发热螺旋体病是一种全球性的疾病，由软壳硬体硬虱或人体虱子传播。在世界各地，如果不加以治疗，这种疾病会导致严重的发病率和死亡率，主要影响资源贫乏国家的患者。然而，关于螺旋体从壁虱媒介传播到脊椎动物宿主的分子机制却知之甚少。因此，为了解决NIAID在改善全球健康方面的作用，我对这项提议的目标是确定使一种复发热螺旋体--吐里氏疏螺旋体--定居并随后传播给哺乳动物宿主的遗传因素。此外，斑疹杆菌和莱姆病螺旋体之间有一些区别，这使得斑疹杆菌有利于研究螺旋体与宿主之间的相互作用。这些差异包括质粒的稳定性和在长时间体外培养后的感染性保留，以及在哺乳动物血液中达到高细菌密度的能力。这些差异有助于开展拟议的研究，重点是确定壁虱在壁虱定植和传播过程中外膜蛋白(OMP)的必要性，这些外膜蛋白是从壁虱载体Ornithodoros turicata传播的。编码OMPS的一个基因家族的重要性已经在另一种复发热螺旋体--赫氏疏螺旋体中得到证实。然而，人们对OMPS在其他致病物种中的作用知之甚少。因此，我建议找出编码OMPS的基因，这些基因在滴虫感染期间在滴虫体内上调。将使用基于微阵列的方法来识别这些遗传决定因素，并将确定它们对壁虱定植和传播给哺乳动物的必要性。为了做到这一点，我开发了第一个在斑点滴虫中用于基因失活和互补的系统，并建立了用于这些研究的唯一已知的实验室扁虱群体。这些发现将对阻断该病传播的治疗方法的发展产生广泛的影响，并将增加我们对媒介传播病原体的适应和传播机制的理解。 公共卫生相关性(由申请人提供)：回归热螺旋体是一种通过血液传播的病原体，分布于世界各地，通过扁虱或人体虱子传播。目前尚不清楚这些螺旋体是如何通过壁虱媒介传播的。识别有助于螺旋体在扁虱中定植并传播给哺乳动物的遗传因素将有助于开发防止传播的新疗法。

DESCRIPTION (provided by applicant): Relapsing fever spirochetosis is a global disease transmitted by argasid (soft-shelled) ticks or the human body louse. Throughout the world, this disease causes severe morbidity and mortality if left untreated, primarily affecting those in resource poor countries. However, little is known regarding the molecular mechanisms involved with transmission of the spirochetes from the tick vector to the vertebrate host. Therefore, to address NIAID's role in improving global health, my goal for this proposal is to identify the genetic factors that enable a species of relapsing fever spirochetes, Borrelia turicatae, to colonize the tick and to be subsequently transmitted to the mammalian host. Furthermore, there are several distinctions between B. turicatae and Lyme disease-causing spirochetes which make B. turicatae advantageous for studying spirochete-host interactions. These differences include plasmid stability and retention of infectivity after prolonged in vitro cultivation, and the ability to reach high bacterial densities in mammalian blood. These distinctions have aided in the development of the proposed studies focusing on determining the necessity of outer membrane proteins (Omps) during tick colonization and transmission of B. turicatae from its tick vector, Ornithodoros turicata. The importance of a family of genes which code for Omps has been established in a different species of relapsing fever spirochetes, Borrelia hermsii. However, little is known about the role of Omps in other species that cause disease. Therefore, I propose to identify genes which code for Omps that are up-regulated within B. turicatae during tick infection. A microarray based approach will be used to identify these genetic determinants, and their necessity for tick colonization and transmission to the mammal will be determined. To accomplish this, I have developed the first system in B. turicatae for gene inactivation and complementation, and have established the only known laboratory tick colony for these studies. These findings will have a broad impact enabling the development of therapeutics blocking transmission of this disease, and will increase our understanding of the adaptation and transmission mechanisms of vector-borne pathogens. PUBLIC HEALTH RELEVANCE (provided by applicant): Relapsing fever spirochetes are a blood-borne pathogen that are distributed throughout the world and are transmitted by ticks or the human body louse. It is poorly understood how these spirochetes are transmitted from their tick-vector. Identifying the genetic factors which aid in spirochete colonization in tick and transmission to the mammal will aid in developing novel therapeutics preventing transmission.