Salmonella Genes Associated with Colonization of Specific Hosts

鼠伤寒沙门氏菌具有非常广泛的宿主范围，并且可以定殖于不同门。迄今为止，只有一小部分的基因组已调查的基因，不同的贡献，不同的殖民不同的主机。该项目旨在确定在三种脊椎动物宿主种属（小鼠、猪和鸡）的定殖过程中，哪些鼠伤寒突变体无法与野生型完全竞争，这些宿主种属因其系统发育多样性和已知对鼠伤寒感染的易感性而被选择。将每个非必需鼠伤寒沙门氏菌基因的体外特异性敲除突变体库（约3900个敲除）灌胃给药至模型动物。通过在感染后3天解剖宿主组织来监测肠道中的短期定殖。一个新设计的寡核苷酸阵列将被用来识别在竞争性定殖过程中变得更加罕见的所有突变体，表明该基因在该过程中的作用。一种新的波动测试将确保只有适当的实验将被应用到阵列。我们已经证实，拟议的检测方法检测几乎所有的基因，已知有助于腹腔内和胃内感染的小鼠。如果数据表明一种宿主中已知的定殖机制可能无法用于其他宿主，则将通过测试这些物种中的单个示例基因敲除突变体来独立证实这一点。新的主机限制的殖民机制超出了这个为期两年的项目的范围，将进行研究，只有在时间和资源允许的情况下。

Salmonella enterica serovar Typhimurium has a very broad host range and can colonize different Phyla. To date, only a small fraction of its genome has been surveyed for genes that differ in their contribution to colonization of different hosts. This project is designed to determine which Typhimurium mutants are unable to fully compete with wild type during colonization of three vertebrate host species, selected for their phylogenetic diversity and known susceptibility to Typhimurium infection: mouse, pig, and chicken. A pool of specific knockout mutants in every non-essential Typhimurium gene in vitro (~3900 knockouts) will be delivered intragastrically to the model animals. Short-term colonization in the gut will be monitored by dissection of host tissues at three days post infection. An oligonucleotide array with a novel design will be used to identify all mutants that become rarer during competitive colonization, indicating a role of that gene in the process. A novel fluctuation test will assure that only appropriate experiments will be applied to arrays. We have confirmed that the proposed assay detects almost all genes that are known to contribute to intraperitoneal and intragastric infection in the mouse. If the data suggest that a known colonization mechanism in one host may not be used in other hosts, this will be independently confirmed by testing single exemplar gene knockout mutants in these species. Novel host-restricted colonization mechanisms are beyond the scope of this two year project and will be studied, only if time and resources permit.