GENE ANALYSIS OF SPIROCHETE PERIPLASMIC FLAGELLA

描述(改编自申请人的摘要)：螺旋体是一种 具有重要医学意义但却鲜为人知的一群 细菌。这些微生物会引起各种重要疾病。 包括梅毒、莱姆病、回归热和钩端螺旋体病。 它们还与牙周病和人类腹泻有关。 疾病。本提案旨在回答与以下有关的某些问题 对螺旋体周质鞭毛(PFS)结构和运动性的影响。 螺旋体PFS是所有细菌鞭毛纤维中最复杂的。 在PFS的表面有一个由一到两个组成的蛋白质鞘 Flaa蛋白种类。核心由三到三个组分的聚合物组成 有四种蛋白质被称为FLAB蛋白质。的功能 个别的Pf蛋白尚不清楚。为了更好地理解角色 在这些具有PF结构和运动性的蛋白质中，申请人建议 敲除几个与PF合成有关的基因。模型系统 正在使用的是猪痢疾瑟普氏菌，正式名称为密螺旋体 猪痢疾。猪瘟沙门氏菌是唯一一种 特异性基因失活已经实现。这些螺旋体有PFS 与在梅毒螺旋体中发现的非常相似，梅毒螺旋体是一种病原体 治疗梅毒。梅毒螺旋体仍不能连续培养，让 单独被操控用于突变分析。因此，因为两者的PFS 生物体是如此相似，在猪痢疾链球菌身上所取得的结果 将与梅毒螺旋体PF的结构和运动性有关。申请人 已经构建了三个PF突变体，FlaA1，FLAB1，FLAALFLAB1 电穿孔和等位基因交换。他们假设这些变种人 已经改变了PF结构，并且改变后的PFS导致效率低下 游泳。为了测试这一点，他们将分析PF的结构和运动性 突变体，并与野生型进行比较。要增强上述功能 实验中，他们将构建和分析其他运动性突变体。 这些突变体包括flB2基因的等位基因交换突变体， 以及flgE基因。后一种基因编码钩子基因，突变 这种基因的突变应该会导致细胞完全缺乏PFS。这个 所获得的结果应该会使我们清楚地理解 这些蛋白质具有PF的结构和运动性。建议的实验是 第一个用系统的分子研究螺旋体运动的人- 遗传方法。它们在鞭毛和/或 运动性被认为是螺旋体的毒力因素和几个 其他种类的病原菌。

DESCRIPTION (Adapted from applicant's abstract): Spirochetes are a medically significant but a remarkable poorly understood group of bacteria. These organisms cause a variety of important diseases including syphilis, Lyme disease, relapsing fever, and leptospirosis. They are also implicated in periodontal disease and human diarrheal disease. The present proposal aims to answer certain questions relating to the structure of spirochete periplasmic flagella (PFs) and motility. Spirochete PFs are the most complex of any bacterial flagellar filament. On the surface of the PFs is a protein sheath comprised of one to two FlaA protein species. The core is comprised of a polymer of three to four protein species referred to as FlaB proteins. The function of the individual PF proteins is not understood. To better understand the roles of these proteins in PF structure and motility, the applicant proposes to knock-out several genes involved in PF synthesis. The model system being used is Serpulina hyodysenteriae, formally known as Treponema hyodysenteriae. S. hyodysenteriae is the only spirochete species in which specific gene inactivation has been achieved. These spirochetes have PFs very similar to those found in Treponema pallidum, the causative agent for syphilis. T. pallidum still cannot be continuously cultured, let alone be manipulated for mutant analysis. Thus, because the PFs of both organisms are so similar, the results achieved with S. hyodysenteriae will be relevant to T. pallidum PF structure and motility. The applicant already has constructed three PF mutants, flaA1, flaB1, flaAlflaB1 by electroporation and allelic exchange. They hypothesize that these mutants have altered PF structure and that the altered PFs result in inefficient swimming. To test this, they will analyze PF structure and motility of the mutants, and make comparisons to the wild-type. To augment the above experiments, they will construct and analyze other motility mutants. These mutants include allelic exchange mutants in both the flaB2 gene, and the flgE gene. The latter gene encodes the hook gene, and mutations in this gene should result in cells completely deficient in PFs. The results obtained should lead to a clear understanding of the function of these proteins in PF structure and motility. The experiments proposed are the first to examine spirochete motility using a systematic molecular- genetic approach. They are especially relevant in that flagella and/or motility are implicated as a virulence factor for spirochetes and several other species of pathogenic bacteria.