替代性伤寒毒素组合在两个Salmonella物种中独立演变
Antonio J Chemello1, Casey C Fowler1
1Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
mBio
|March 19, 2024
概括
沙门氏菌 bongori 独立进化了两种伤寒毒素,类似于沙门氏菌 Typhi. 这种融合进化突显了AB5型毒素的灵活性和它们在细菌毒性中的作用.
科学领域:
- 微生物学 微生物学
- 进化生物学 进化生物学
- 毒理学 毒理学 毒理学
背景情况:
- AB5型毒素是细菌病原体中关键的毒性因素.
- 沙门氏菌Typhi产生了两个不同的伤寒毒素,具有相同的A子单元但不同的B子单元 (PltB和PltC).
- 这种独特的"双毒素"系统在S. Typhi有影响,了解病变发生和开发治疗方法.
研究的目的:
- 为了调查沙门氏菌是否独立进化了类似的两种毒素系统.
- 为了比较毒素组合,宿主细胞中毒以及S. bongori和S. Typhi的进化意义.
- 探索AB5型毒素进化中的AB-B亚单元灵活性更广泛的影响.
主要方法:
- 对比基因组分析以确定S. bongori中的毒素子单元.
- 对S. bongori的伤寒毒素变体的生物化学表征.
- 在体外感染模型使用培养的人类上皮细胞来评估中毒水平.
- 对S. bongori菌株进行基因操纵,以研究毒素功能.
主要成果:
- S. bongori独立进化了第二种伤寒毒素,利用一种新的B子单元PltD,它在进化上与PltB和PltC不同.
- 在S. bongori中,PltD超过了PltB,形成了占主导地位的毒素.
- S. bongori表现出与S. Typhi类似的CdtB介导的中毒水平,主要是由于PltB毒素.
- 缺乏pltD的菌株显示PltB毒素的产量增加和毒性增加,这表明PltD的获取可能会降低S. bongori的毒性.
结论:
- 沙门氏菌戈里通过独立开发为伤寒毒素的两种毒素系统来表现出融合进化.
- 在A-B亚单元相互作用的灵活性是AB5型毒素多样化和进化的关键驱动力.
- "两毒素"范式是伤寒毒素生物学的一个关键方面,对细菌病原和进化有重大影响.
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