在Toxoplasma gondii中代谢适应性和营养清理:从摄入途径缺陷突变体的洞察力
Patrick A Rimple1, Einar B Olafsson1, Benedikt M Markus2
1Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
mSphere
|April 2, 2025
概括
毒素菌使用摄入途径来吸收宿主营养,这对于寄生虫的生存至关重要. 破坏这种途径迫使人们依赖其他代谢途径,特别是在营养稀缺的情况下.
科学领域:
- 寄生虫学的寄生虫学
- 分子生物学分子生物学
- 宿主-病原体相互作用
背景情况:
- 毒素虫是一种有义务的细胞内寄生虫,需要来自宿主的营养来进行复制.
- 寄生虫利用一个专门的摄入途径将宿主蛋白内化到寄生虫的真空体 (PV).
- 这一途径涉及密集颗粒蛋白GRA14,用于运输 (ESCRT) 机器所需的内体组分复合体,甲素蛋白酶L (CPL) 和氨酸耐药性运输体 (CRT).
研究的目的:
- 调查Toxoplasma gondii摄入途径在营养获取中的作用.
- 识别宿主基因,当摄入途径受损时,这些基因对寄生虫的健康状况至关重要.
- 为了理解Toxoplasma gondii突变的代谢适应,缺乏摄入途径的关键成分.
主要方法:
- 在野生型和突变型Toxoplasma gondii菌株 (Δgra14, Δcpl, Δcrt) 中进行全基因组集群定期间隔的短时间palindromic重复 (CRISPR) 屏幕.
- 在CRISPR屏幕中识别的基因的途径分析.
- 野生类型和摄入突变寄生虫的批量代谢分析.
- 在缺乏营养的介质中进行生长测试.
主要成果:
- 与野生类型寄生虫相比,CRISPR屏幕揭示了摄入突变物中的重叠基因适应性变化.
- Δcpl 和 Δcrt 突变体对胺生物合成,脂肪酸生物合成,三碳酸 (TCA) 循环和氨酸降解的依赖性增加.
- 代谢分析表明,摄入突变体中减少了糖溶性中间体和氨基酸,这表明它在宿主资源清理中发挥了作用.
- 在缺乏氨基酸的介质中,Δcpl和Δcrt突变体表现出恶化的生长缺陷.
结论:
- 毒素菌的摄入途径对于吸收宿主营养,特别是氨基酸至关重要.
- 摄入途径的损害迫使寄生虫对替代代代谢途径进行上调,以求生存.
- 在营养限制条件下,通过CPL降解摄入的蛋白质和通过CRT出口的蛋白质对于寄生虫适应性至关重要.
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