CO2-dependent carbon isotope fractionation in Archaea, Part I: Modeling the 3HP/4HB pathway
CO2-dependent carbon isotope fractionation in Archaea, Part I: Modeling the 3HP/4HB pathway
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古细菌中 CO2 依赖性碳同位素分馏，第一部分：3HP/4HB 途径建模
DOI：
10.1016/j.gca.2019.06.042
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发表时间：
2019
影响因子：
5
通讯作者：
Wilkes, Elise B.
中科院分区：
文献类型：
--
作者：
Pearson, Ann;Hurley, Sarah J.;Elling, Felix J.;Wilkes, Elise B.
摘要3-羟基丙酸/4-羟基丁酸（3 HP/4 HB）碳固定途径存在于嗜热泉古菌和好氧氨氧化泉古菌中。与所有其他已知的自养碳代谢不同，该途径仅使用HCO 3−而不是CO 2作为碳固定的底物。3 HB/4 HP途径产生的生物量与其他自养途径固定的生物量相比相对富集13 C，总生物合成同位素效应（ε Ar）约为13 C。3‰的Sulfolobales和ca. 20‰的Thaumarchaeota。对这些值之间的差异的解释通常引起了前一组的嗜热性和在低pH（低[HCO 3-]）下生长与后一组的嗜中性和在pH> 7（高[HCO 3-]）下生长的双重效应。在这里，我们研究了模式类群Metallosphaera sedula和Nitrosopumilus maritimus使用同位素通量平衡模型，认为不同的ε Ar值的主要原因更可能是碳酸酐酶的存在下，在M。sedula和相应的缺失。maritimus结果表明，氮素中HCO 3-库是氮素中的主要来源.海洋生物与CO2的同位素平衡失调，生物体从细胞外环境输入< 10%的HCO 3-。如果正确的和普遍的，好氧，氨氧化海洋Thaumarchaeota依赖于被动的CO2吸收和细胞内转化为H C O 3-的缓慢速率。因此，ε Ar值应随生长速率（μ）和CO2可用性而变化，类似于真核藻类，但方向相反：ε Ar随[CO2（aq）]增加和/或μ减小而变小。这样的想法代表了一个可以在实验室和自然系统中检验的假设。对μ和CO2的敏感性意味着ε Ar的测量可能有希望作为pCO 2古压力计。
Abstract The 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) pathway of carbon fixation is found in thermophilic Crenarchaeota of the order Sulfolobales and in aerobic, ammonia-oxidizing Thaumarchaeota. Unlike all other known autotrophic carbon metabolisms, this pathway exclusively uses HCO 3− rather than CO 2 as the substrate for carbon fixation. Biomass produced by the 3HB/4HP pathway is relatively 13 C-enriched compared to biomass fixed by other autotrophic pathways, with total biosynthetic isotope effects (ε Ar) of ca. 3‰ in the Sulfolobales and ca. 20‰ in the Thaumarchaeota. Explanations for the difference between these values usually invoke the dual effects of thermophily and growth at low pH (low [H C O 3-]) for the former group vs. mesophily and growth at pH> 7 (high [H C O 3-]) for the latter group. Here we examine the model taxa Metallosphaera sedula and Nitrosopumilus maritimus using an isotope flux-balance model to argue that the primary cause of different ε Ar values more likely is the presence of carbonic anhydrase in M. sedula and its corresponding absence in N. maritimus. The results suggest that the pool of H C O 3-inside N. maritimus is out of isotopic equilibrium with CO 2 and that the organism imports< 10% H C O 3-from the extracellular environment. If correct and generalizable, the aerobic, ammonia-oxidizing marine Thaumarchaeota are dependent on passive CO 2 uptake and a slow rate of intracellular conversion to H C O 3-. Values of ε Ar should therefore vary in response to growth rate (μ) and CO 2 availability, analogous to eukaryotic algae, but in the opposite direction: ε Ar becomes smaller as [CO 2 (aq)] increases and/or μ decreases. Such an idea represents a testable hypothesis, both in the laboratory and in natural systems. Sensitivity to μ and CO 2 implies that measurements of ε Ar may hold promise as a pCO 2 paleobarometer.
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影响因子：
3.9
作者：
K. Taylor;M. Huber;C. Hollis;M. Hernández-Sánchez;R. Pancost
通讯作者：
K. Taylor;M. Huber;C. Hollis;M. Hernández-Sánchez;R. Pancost
化合物特异性同位素分馏模式表明温泉微生物垫中类绿屈菌细菌的碳代谢不同
影响因子：
4.4
作者：
M. V. D. van der Meer;Stefan Schouten;J. S. Sinninghe Damsté;J. D. de Leeuw;D. M. Ward
通讯作者：
D. M. Ward
影响因子：
4.4
作者：
Hawkins, Aaron B.;Adams, Michael W. W.;Kelly, Robert M.
通讯作者：
Kelly, Robert M.
DOI：
10.1073/pnas.96.26.15184
发表时间：
1999-12-21
影响因子：
11.1
作者：
Smith, KS;Jakubzick, C;Ferry, JG
通讯作者：
Ferry, JG
影响因子：
5
作者：
A. Pearson;Sarah J. Hurley;S. R. S. Walter-S.-R.-S.-Walter-39267913;S. Kusch;S. Lichtin;Yi Ge Zhang
通讯作者：
A. Pearson;Sarah J. Hurley;S. R. S. Walter-S.-R.-S.-Walter-39267913;S. Kusch;S. Lichtin;Yi Ge Zhang