克洛洛比比晚期收购了rTCA碳固定路径
Xiaowen Zhang1,2, Madeline M Paoletti3, Gareth Izon3
1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA. xiaowenz@sjtu.edu.cn.
Nature ecology & evolution
|August 3, 2023
概括
逆三碳酸 (rTCA) 循环的逆三碳酸 (rTCA) 循环.
科学领域:
- 生物地质化学生物地质化学
- 古生物学的古生物学
- 进化生物学 进化生物学
背景情况:
- 反向三碳酸 (rTCA) 循环被认为是一种古老的碳固定途径.
- 在早期的岩石记录中,对rTCA周期的古老性的证据是有限的.
- 遗传学数据表明,在Chlorobiaceae中,rTCA循环的获取时间较晚.
研究的目的:
- 通过使用化学化石,研究古代Chlorobiaceae的生理能力.
- 为了确定在Chlorobiaceae中rTCA循环组装的时间.
- 了解在生命早期推动代谢变化的进化压力.
主要方法:
- 分析了164亿年前的巴尼溪形成样本.
- 化合物特定的碳同位素测量胡卜素 (chlorobactane).
- 鉴定共存的蓝藻细菌和异质型细菌生物标志物.
主要成果:
- 来自巴尼克里克形成的甲与现代等价物相比,13C含量显著减少.
- 同位素数据显示相对于与共存的蓝藻细菌胡卜素相对较少的13C丰富.
- 这种同位素特征表明,这些古老的生物体中缺乏通过rTCA循环的自营性碳固定.
结论:
- 这些发现支持rTCA循环的晚期组装和Chlorobiaceae中的延迟自.
- 早期的生态系统很可能由异构细菌和蓝藻细菌主导.
- 地球的氧化和硫酸盐水平的增加可能推动了新新生态时期的转向光自otrophy.
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