Salmonella Genes Associated with Colonization of Specific Hosts

肠炎沙门氏菌血清型鼠伤寒沙门氏菌具有非常广泛的宿主范围，可以定植于不同的门。到目前为止，只有一小部分基因组被调查，以寻找对不同宿主定植的不同贡献的基因。该项目旨在确定鼠伤寒菌突变体在三种脊椎动物宿主物种（小鼠、猪和鸡）定植过程中无法与野生型完全竞争，这三种动物宿主物种因其系统发育多样性和已知的鼠伤寒菌感染易感性而被选中。每个非必需鼠伤寒杆菌基因的特异性敲除突变体（约3900个敲除）将在体外给模型动物灌胃。在感染后三天，通过解剖宿主组织来监测肠道内的短期定植。一种新型设计的寡核苷酸阵列将用于鉴定在竞争定植过程中变得罕见的所有突变体，表明该基因在该过程中的作用。一种新颖的波动试验将确保只对阵列进行适当的实验。我们已经证实，提出的分析检测几乎所有已知的基因，有助于腹腔和胃内感染的小鼠。如果数据表明在一个宿主中的已知定植机制可能不适用于其他宿主，这将通过在这些物种中测试单个范例基因敲除突变体来独立证实。新的寄主限制的殖民化机制超出了这个为期两年的项目的范围，只有在时间和资源允许的情况下才会进行研究。

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.