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首页> 外文期刊>Infection and immunity >Mutations at rfc or pmi attenuate Salmonella typhimurium virulence for mice.
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Mutations at rfc or pmi attenuate Salmonella typhimurium virulence for mice.

机译：在rfc或pmi处的突变会减弱鼠伤寒沙门氏菌的毒性。

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Insertion mutations were constructed in cloned pmi and rfc genes of Salmonella typhimurium, and these mutations were recombined (singly) into the chromosome of mouse-virulent S. typhimurium C5, displacing the wild-type alleles. Phage sensitivity profiles, lipopolysaccharide analysis, and DNA blotting all confirmed that the replacement events had occurred. The mutations were complemented by plasmid-borne wild-type alleles, as judged by the restoration of wild-type phage plaquing profiles and lipopolysaccharide production (both mutants) and the restoration of pmi-encoded enzyme production (pmi mutant). The virulence, persistence, and immunizing capacities of the mutants fed to mice were compared with those of the wild-type strain and complemented mutants. Both mutants were much reduced in virulence, with the rfc mutant being avirulent even at 10(9) bacteria per mouse. This mutant was also avirulent at up to 10(6) bacteria per mouse when administered intraperitoneally. Both the rfc and pmi mutant strains persisted in the Peyer's patches of the gut after feeding and were capable of colonizing the deeper tissues of the mice from such initial infective foci. Both mutant strains were effective as live oral vaccines (10(7) bacteria or more) against oral S. typhimurium challenge (10(4) 50% lethal doses; 6 x 10(8) bacteria) in mice.
机译：在鼠伤寒沙门氏菌的克隆的pmi和rfc基因中构建了插入突变，并将这些突变重组（单独）到小鼠致病性鼠伤寒沙门氏菌C5的染色体中，取代了野生型等位基因。噬菌体敏感性概况，脂多糖分析和DNA印迹均证实发生了置换事件。根据野生型噬菌体斑块分布和脂多糖生产（两个突变体）和pmi编码酶生产（pmi突变体）的恢复判断，质粒携带的野生型等位基因对突变进行了补充。将饲喂小鼠的突变体的毒力，持久性和免疫能力与野生型菌株和互补突变体的毒力，持久性和免疫能力进行了比较。两种突变体的毒力都大大降低，即使每只小鼠10（9）个细菌，rfc突变体也无毒。腹膜内给药时，该突变体对每只小鼠的多达10（6）个细菌也无毒。喂食后，rfc和pmi突变株都在肠道的Peyer斑中存留，并且能够从这种最初的感染灶定居小鼠的更深组织。两种突变株均作为活的口服疫苗（10（7）细菌或更多）有效对抗小鼠鼠伤寒沙门氏菌攻击（10（4）50％致死剂量; 6 x 10（8）细菌）。

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