Redox-Related Metabolic Dynamics Imprinted on Short-Chain Carboxylic Acids in Soil Water Extracts: A 13 C-Exometabolomics Analysis
Redox-Related Metabolic Dynamics Imprinted on Short-Chain Carboxylic Acids in Soil Water Extracts: A 13 C-Exometabolomics Analysis
复制标题
土壤水提取物中短链羧酸的氧化还原相关代谢动力学：13 C-外代谢组学分析
DOI：
10.1021/acs.estlett.0c00922
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发表时间：
2021
影响因子：
10.9
通讯作者：
Aristilde, Ludmilla
中科院分区：
文献类型：
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作者：
Hassanpour, Bahareh;Aristilde, Ludmilla
土壤微生物代谢对于碳循环至关重要，但代谢活动的直接注释具有挑战性。在这里，我们提出了一种外代谢组学方法，结合 13 C 分析，用于在含氧或缺氧土壤培养中进行 13 C-葡萄糖脉冲后原位探测代谢活动。在土壤水提取物中，我们监测了参与不同代谢途径的短链羧酸（SCCA）的丰度和同位素富集：外周糖氧化、糖酵解、发酵和三羧酸循环。可水提取的 SCCA 捕获了氧化还原依赖性代谢动力学。首先，在两种氧化还原条件下，葡萄糖酸和2-酮葡萄糖酸的浓度增加（高达50 μM）以及接近完整的13 C标记级分揭示了外周糖氧化途径的激活。其次，有氧条件下柠檬酸盐的消耗量比缺氧条件下更大（6.2 μM vs 2.3 μM），这与缺氧培养中碳用量的预期减少一致。第三，仅在缺氧培养中13 C标记的琥珀酸和苹果酸的积累证明了厌氧代谢的典型代谢溢出。第四，缺氧条件下13 C标记的乳酸的产生突出了葡萄糖发酵，但在有氧条件下，乳酸消耗暗示了其作为碳源的作用。这种13 C辅助的外代谢组学数据为解释基于基因的代谢潜力预测提供了见解。
Soil microbial metabolism is critical to carbon cycling, but direct annotation of metabolic activities is challenging. Here, we present an exometabolomics approach coupled with13C profiling forin situprobing of metabolic activities following a13C-glucose pulse in oxic or anoxic soil incubations. In the soil water extracts, we monitored both abundance and isotopic enrichment of short-chain carboxylic acids (SCCAs) involved in different metabolic pathways: peripheral sugar oxidation, glycolysis, fermentation, and the tricarboxylic acid cycle. The water-extractable SCCAs captured redox-dependent metabolic dynamics. First, under both redox conditions, increased concentration (up to 50 μM) along with near-complete13C-labeled fractions for both gluconate and 2-ketogluconate revealed activation of the peripheral sugar oxidation pathway. Second, greater citrate depletion during the oxic condition than during the anoxic condition (6.2 versus 2.3 μM) was consistent with an expected decrease in carbon usage in the anoxic incubations. Third, accumulation of13C-labeled succinate and malate only in the anoxic incubations demonstrated metabolic overflow typical of anaerobic metabolism. Fourth, production of13C-labeled lactate under the anoxic conditions highlighted glucose fermentation but, under the oxic conditions, lactate depletion implied its role as a carbon source. Such13C-assisted exometabolomics data offer insights to interpret gene-based predictions of metabolic potentials.