重温氧毒性:SOD缺乏的细菌病原体中的进化和适应超氧化物
Samuel G Huete1, Alejandro Leyva2, Etienne Kornobis3,4
1Biology of Spirochetes, Institut Pasteur, CNRS UMR 6047, Université Paris Cité, Paris, France.
mBio
|July 23, 2025
概括
缺乏超氧化物脱酶 (SOD) 的致病细菌通过重新连接其新陈代谢来适应有毒的超氧化物,从而调节氨酸生物合成和异甲酸盐合成等途径. 这挑战了传统的氧毒性理论.
科学领域:
- 微生物学和分子生物学
- 进化生物学 进化生物学
- 生物化学 生物化学
背景情况:
- 有氧生命依赖于二氧化物 (O2),但其代谢产生有毒的超氧化物 (O2-).
- 超氧化物清除酶 (SOSEs),像超氧化物解酶 (SODs),被认为是有氧生物必不可少的.
- 许多生物体,包括病原体,缺乏SOSEs,但它们对超氧化物的生存机制仍然不太了解.
研究的目的:
- 为了研究致病性LeptoSpira物种中SOD的进化损失.
- 为了确定超氧化物应激适应在SOSE缺陷的LeptoSpira中的替代机制.
- 提出一种新的超氧化物适应模型,用于缺乏SOSEs的有氧细菌.
主要方法:
- 对比基因组学和遗传学分析,以追踪Leptospira中的SOD进化.
- 在Leptospira中SOD的异质表达,以评估其功能作用.
- 多组学方法 (转录组学,蛋白组学) 用于在超氧化压力下识别上调的因素.
- 代谢途径分析侧重于白和氨酸的生物合成.
主要成果:
- SOD是Leptospira的祖先,但在致病物种中消失了;它的重新引入并没有提高超氧化物耐受性.
- 勒普托斯皮拉探究者通过包括MFS转运器在内的遗传基因位点的上调调节来适应超氧化物.
- 超氧化压力显著上调异甲酸盐合成酶 (LeuA2) 和囊蛋白生物合成途径,表明代谢重新连接.
结论:
- 致病性LeptoSpira已经开发出了替代策略,以在没有SOD的情况下对抗超氧化物毒性.
- 基于氧化还原的代谢重编程,特别是涉及硫代谢和氨酸生物合成,是超氧化物适应的关键.
- 这项研究挑战了对SOSE的普遍要求,并提出了一个新的SOSE缺乏细菌有氧生存模型.
相关概念视频
01:29Oxygen Requirements and Growth Patterns
249
Microorganisms exhibit diverse oxygen requirements and growth patterns driven by their metabolic strategies and environmental adaptations. Oxygen, while essential for many organisms, can also be toxic under certain conditions, shaping how microorganisms grow and survive.Oxygen Requirements of MicroorganismsMicroorganisms are classified based on their ability to use or tolerate oxygen:● Obligate aerobes like Mycobacterium tuberculosis need oxygen for energy production, as it serves as the...
249
01:30Anoxygenic Photosynthesis
158
Anoxygenic photosynthesis is a phototrophic process that captures light energy to drive carbon fixation without producing molecular oxygen. Unlike oxygenic photosynthesis, which utilizes water as an electron donor and releases oxygen, anoxygenic phototrophs use alternative electron donors such as hydrogen sulfide (H₂S), elemental sulfur (S⁰), or thiosulfate (S₂O₃²⁻). This process is carried out by diverse groups of bacteria, including purple bacteria, green...
158
01:16Transduction
117
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome...
117
01:28Carbon-dioxide Fixation
87
Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
87
01:31Defense Against Bacterial Pathogens
1.5K
The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
1.5K
01:28Microbial Nutrition
309
Organisms exhibit remarkable metabolic diversity, categorized based on how they acquire energy and carbon. These strategies enable survival in various ecological niches and are essential for maintaining energy flow and nutrient cycling within ecosystems.Energy and Carbon SourcesOrganisms are classified as phototrophs or chemotrophs based on energy acquisition. Phototrophs use light as their energy source, while chemotrophs rely on oxidizing chemical compounds. Further differentiation arises...
309