Genome Evolution in Pathogens: The roles of predator-prey interactions

病原体的基因组进化:捕食者与猎物相互作用的作用

基本信息

项目摘要

DESCRIPTION (provided by applicant): The pathogen Salmonella enterica is a common commensal inhabitant of mammalian, reptilian and avian intestinal environments. Like many pathogens, it shows extreme genetic variation at genes encoding structures presented on the outside of the cell (antigens). In most organisms, it is thought that exposure to the immune system during infection provides frequency-dependent selection for rare antigenic types, allowing escape. Yet unlike other pathogens, Salmonella does not alter its major outer-membrane polysaccharide (the O-antigen) during infection; on the contrary, serovars with certain O-antigens show specificity in terms of which hosts they will infect. These data show that factors other than exposure to the immune system must drive selection for variability at the Salmonella O-antigen. We propose that this variation is maintained because it allows different strains of Salmonella to prosper in environments which harbor different suites of protozoan predators which inhabit the intestine. Preliminary data show that amoeboid predators discriminate among Salmonella serovars based on differences in their O-antigens, and that different predators have different preferences. We propose to determine the degree to which the distribution of intestinal protozoa influences the ability of Salmonella to colonize the gut environment via isolation and characterization of Salmonella and their co-resident predators from avian and reptilian intestinal environments. The relative contributions the O-, H- and other antigens in predator/prey interactions will be assessed by the construction of isogenic strains that vary only at the rfb and/or fliC loci. Predator/host interactions will be assessed by examining the non-random distribution of predators among hosts, which provide the foundation for diversifying selection. The prey/host interaction - as mediated by the predator - will be assessed by competition experiments performed inside vertebrate hosts using fluorescently-tagged bacteria; the use of anti-protozoan drugs will allow the dissection of adaptive traits unrelated to predation from the effect of local intestinal predators. In total, these experiments test the hypothesis that protozoan predation may play a role in the distribution of Salmonella and other bacteria among natural intestinal environments, and the role of variability at the O-antigen in mediating host-serovar specificity.
描述(由申请方提供):病原体肠道沙门氏菌是哺乳动物、爬行动物和鸟类肠道环境中常见的寄生菌。像许多病原体一样,它在编码细胞外部结构(抗原)的基因上显示出极端的遗传变异。在大多数生物体中,人们认为在感染期间暴露于免疫系统提供了对罕见抗原类型的频率依赖性选择,从而允许逃逸。然而,与其他病原体不同的是,沙门氏菌在感染过程中不会改变其主要的外膜多糖(O抗原);相反,具有某些O抗原的血清型在它们将感染的宿主方面表现出特异性。这些数据表明,除了暴露于免疫系统之外的因素必须驱动沙门氏菌O抗原变异性的选择。我们认为,这种变化是保持,因为它允许不同菌株的沙门氏菌繁荣的环境中,窝藏不同套房的原生动物捕食者居住在肠道。初步数据显示,变形虫捕食者区分沙门氏菌血清型的基础上,他们的O-抗原的差异,不同的捕食者有不同的偏好。我们建议确定肠道原生动物的分布影响沙门氏菌的能力,通过分离和表征沙门氏菌和他们的共同居民捕食者从鸟类和爬行动物肠道环境的肠道环境殖民化的程度。通过构建仅在rfb和/或fliC位点变化的等基因菌株,评估O-、H-和其他抗原在捕食者/猎物相互作用中的相对贡献。捕食者/主机的相互作用将通过检查非随机分布的捕食者之间的主机,这提供了多样化的选择的基础进行评估。猎物/宿主的相互作用-介导的捕食者-将进行评估的竞争实验内脊椎动物宿主使用荧光标记的细菌;使用抗原生动物药物将允许解剖的适应性特征无关的捕食当地肠道捕食者的影响。总之,这些实验测试的假设,原生动物捕食可能发挥作用的沙门氏菌和其他细菌之间的自然肠道环境中的分布,以及在O-抗原的变异性介导的主机血清型特异性的作用。

项目成果

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Jeffrey G Lawrence其他文献

Why genomics is more than genomes
  • DOI:
    10.1186/gb-2004-5-12-357
  • 发表时间:
    2004-01-01
  • 期刊:
  • 影响因子:
    9.400
  • 作者:
    Jeffrey G Lawrence
  • 通讯作者:
    Jeffrey G Lawrence

Jeffrey G Lawrence的其他文献

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{{ truncateString('Jeffrey G Lawrence', 18)}}的其他基金

EVOLUTION OF COBALAMIN SYNTHETIC GENES AMONG ENTERIC BACTERIA
肠道细菌中钴胺素合成基因的进化
  • 批准号:
    7956080
  • 财政年份:
    2009
  • 资助金额:
    $ 22.15万
  • 项目类别:
EVOLUTION OF COBALAMIN SYNTHETIC GENES AMONG ENTERIC BACTERIA
肠道细菌中钴胺素合成基因的进化
  • 批准号:
    7723122
  • 财政年份:
    2008
  • 资助金额:
    $ 22.15万
  • 项目类别:
Genome Evolution in Pathogens: The roles of predator-prey interactions
病原体的基因组进化:捕食者与猎物相互作用的作用
  • 批准号:
    7630595
  • 财政年份:
    2007
  • 资助金额:
    $ 22.15万
  • 项目类别:
Genome Evolution in Pathogens: The roles of predator-prey interactions
病原体的基因组进化:捕食者与猎物相互作用的作用
  • 批准号:
    7884114
  • 财政年份:
    2007
  • 资助金额:
    $ 22.15万
  • 项目类别:
Genome Evolution in Pathogens: The roles of predator-prey interactions
病原体的基因组进化:捕食者与猎物相互作用的作用
  • 批准号:
    7489293
  • 财政年份:
    2007
  • 资助金额:
    $ 22.15万
  • 项目类别:
EVOLUTION OF COBALAMIN SYNTHETIC GENES AMONG ENTERIC BACTERIA
肠道细菌中钴胺素合成基因的进化
  • 批准号:
    7601298
  • 财政年份:
    2007
  • 资助金额:
    $ 22.15万
  • 项目类别:
Inferring the Roadmap of Bacterial Gene Transfer
推断细菌基因转移的路线图
  • 批准号:
    7485794
  • 财政年份:
    2006
  • 资助金额:
    $ 22.15万
  • 项目类别:
Inferring the Roadmap of Bacterial Gene Transfer
推断细菌基因转移的路线图
  • 批准号:
    7131452
  • 财政年份:
    2006
  • 资助金额:
    $ 22.15万
  • 项目类别:
Inferring the Roadmap of Bacterial Gene Transfer
推断细菌基因转移的路线图
  • 批准号:
    7261952
  • 财政年份:
    2006
  • 资助金额:
    $ 22.15万
  • 项目类别:
Inferring the Roadmap of Bacterial Gene Transfer
推断细菌基因转移的路线图
  • 批准号:
    7665308
  • 财政年份:
    2006
  • 资助金额:
    $ 22.15万
  • 项目类别:
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