伤寒型沙门氏菌中代谢特征的功能丧失,没有明显的基因组降解
Leopoldo F M Machado1, Jorge E Galán1
1Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA.
mBio
|April 4, 2024
概括
沙门氏菌Typhi和Paratyphi A,人类适应的病原体,在代谢途径中表现出趋同的进化. 沙门氏菌Typhi中单个氨基酸的替代失活了关键的代谢功能,影响了营养的利用.
科学领域:
- 微生物学 微生物学
- 进化生物学 进化生物学
- 生物化学 生物化学
背景情况:
- 沙门氏菌EntericaserovarsTyphi和ParatyphiA导致伤寒和偏伤寒发烧,仅感染人类并建立持久性感染.
- 人类宿主适应导致了这些血清体的显著代谢变化,包括营养利用能力的丧失.
- 趋同进化是显而易见的,两种血清体都在代谢途径中显示了退化的编码序列,通常会影响不同的基因.
研究的目的:
- 研究沙门氏菌Typhi中看起来完好无损,但在沙门氏菌Paratyphi A.中降解的代谢途径的功能.
- 了解这两种适应人类的血清体之间的代谢差异的分子基础.
- 评估特定遗传变化的对代谢能力的影响.
主要方法:
- 对沙门氏菌Typhi和沙门氏菌Paratyphi A.中的代谢途径进行比较基因组分析.
- 识别一种血清器中明显完好且另一种血清器中降解的编码序列.
- 在Salmonella Typhi.中对特定的代谢酶,载体和转录调节物的功能分析.
主要成果:
- 发现沙门氏菌Typhi代谢酶,载体或转录调节器中的单氨基酸替代物会使代谢途径失活.
- 沙门氏菌Typhi不能代谢葡萄糖-6-酸和3-糖酸是由于对影响基因表达的转录调节蛋白的点突变.
- 在沙门氏菌Typhi中无法利用葡萄糖酸或银糖酸是由于必要的载体和酶的点突变造成的.
结论:
- 沙门氏菌Typhi的特定点突变导致关键代谢途径的失活,尽管在序列水平上看起来完好无损.
- 这些发现强化了适应性融合进化在适应人类的沙门氏菌 (Salmonella enterica serovars) 中的概念.
- 生物信息学对代谢能力的预测可能受到影响功能途径的微妙遗传变化的存在的限制.
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