Enterococcus faecalis OG1RF 低pH的进化选择酸盐敏感突变体在延长因子G和高pH选择酸盐运输缺陷
Bailey A Fitzgerald1, Ayman Wadud1, Zachary Slimak1
1Department of Biology, Kenyon College, Gambier, Ohio, USA.
Applied and environmental microbiology
|June 5, 2023
概括
Enterococcus faecalis通过改变延长因子G来适应低pH值,从而降低酸耐药性. 高pH适应涉及酸盐运输和pyrimidine生物合成基因的突变,影响生长权衡.
科学领域:
- 微生物学和分子生物学
- 环境适应 环境适应
- 抗生素耐药性 抗生素耐药性
背景情况:
- 菌细菌居住在不同的环境中,pH值各不相同,包括人类肠道和土壤.
- E. faecalis菌株可以是共生菌或抗生素耐药的病原体,具有临床和环境相关性.
- 牙生物膜和牙内膜感染存在于E. faecalis遇到极端pH条件的环境中.
研究的目的:
- 研究Enterococcus faecalis OG1RF在不同pH压力下 (酸性,中性,基性) 的适应机制.
- 在浮游生物和生物膜培养中识别赋予pH适应的遗传突变.
- 了解与pH适应相关的权衡,特别是关于抗生素耐药性和生长.
主要方法:
- 通过连续浮游生物培养500代的E. faecalis OG1RF的实验进化.
- 在生物膜培养中使用串行珠转移的高pH适应研究.
- 进化克隆的全基因组测序和突变分析.
主要成果:
- 酸适应 (pH4.8) 始终导致fusaA的突变,编码延长因子G,导致酸抗性降低.
- 高pH适应性 (pH 9.0) 为酸盐运输 (pst) 和金胺生物合成 (pyrR) 基因的突变而被选择.
- 在高pH下生物膜适应产生了具有pstB2,pstC或pyrR突变的小殖民地变体,在pH9.2下增长,但在pH4.8下增长减少.
结论:
- E. faecalis表现出强烈的pH依赖性适应性,有利于低pH时的fusa修饰和高pH时的酸盐运输损失.
- pH诱导的突变可以改变抗生素耐药性概况,这对临床环境和使用化剂耐药性的标记有影响.
- 了解E. faecalis进化的pH调节对于管理感染和理解其在土壤和植物根系球等环境环境中的作用至关重要.
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