AN EVOLUTIONARY ANALYSIS OF FIMBRIAE IN ENTEROBACTERIA

描述（改编自申请人的摘要）： 在这项合作中，研究人员建议研究一种 通过选择作用， 预先存在的等位基因，而不是通过获得大量的 不同的基因通过水平转移。(An后者的例子 这种现象是“致病岛”或带有毒素基因的噬菌体。 研究人员使用术语“病理适应”来选择 等位基因变异，“促进细菌病原体适应 特殊的发病机制。“他们建议使用模型系统类型1 大肠杆菌菌毛和粘附素，特别是 用于适应泌尿道和上呼吸道的粘附素。 为了这项研究，研究人员将收集代表性菌株 并进一步表征菌毛基因和控制区域， 基因.他们将使用单链构象多态性和测序 以区分变体并识别适应于 人类宿主微环境的调查类型的研究。在一项前瞻性研究中 他们将使用动物模型来验证他们的假设，即 促进动物泌尿道持久性的菌毛基因将被 然后在人群中被发现。

DESCRIPTION (Adapted from the Applicant's Abstract): The two principal investigators in this collaboration propose to study the evolution of a bacterium from a commensal to a pathogen through selection operating on pre-existing alleles, rather than through the acquisition of substantially different genes through horizontal transfer. (An example of the latter phenomenon is the "pathogenicity island" or a bacteriophage with a toxin gene.) The investigators use the term "pathoadaption" for the process of selection of allele variants that "promote adaptation of the bacterial pathogens to a particular mode of pathogenesis." They propose to use for a model system type 1 fimbriae and adhesins of Escherichia coli and in particular the evolution of the adhesins for adaptation to the urinary tract and upper respiratory tract. For the study, the investigators will gather together representative strains and further characterize the fimbrial genes and the control regions for the genes. They will use Single Stranded Conformational Polymorphism and sequencing to distinguish the variants and to identify "signatures" for adaptation to the human host microenvironment in a survey type of study. In a prospective study they will use an animal model to test their hypothesis that variant alleles of fimbrial genes that promote persistence in the animal urinary tract will be selected and then detected in the population.