Stable isotope switching (SIS): a new stable isotope probing (SIP) approach to determine carbon flow in the soil food web and dynamics in organic matter pools.
Stable isotope switching (SIS): a new stable isotope probing (SIP) approach to determine carbon flow in the soil food web and dynamics in organic matter pools.
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DOI：
10.1002/rcm.6172
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发表时间：
2012-04
期刊：
影响因子：
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通讯作者：
P. Maxfield;N. Dildar;E. Hornibrook;A. Stott;R. Evershed
中科院分区：
文献类型：
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作者：
P. Maxfield;N. Dildar;E. Hornibrook;A. Stott;R. Evershed
稳定同位素探测（SIP）的最新进展已经允许微生物种群结构和功能的直接联系。本文详细介绍了SIP的新发展，稳定同位素转换（SIS），它允许同时评估碳（C）的吸收，周转和衰变，并阐明复杂土壤或沉积基质中的土壤食物网。SIS利用稳定同位素标记方法，其中（13）C-标记的底物通过孵育部分切换到天然丰度底物。对Odcombe（萨默塞特，英国）的垃圾填埋场覆盖土进行了（13）CH（4）SIS研究。碳同化和异化过程进行了监测，通过散装元素分析同位素比质谱和化合物特定的气相色谱/燃烧/同位素比质谱，针对广泛的生物分子成分，包括：脂质，蛋白质和碳水化合物。结果观察到初级消费者（甲烷氧化菌）的碳同化以及次级消费者（革兰氏阴性菌和革兰氏阳性菌）和三级消费者（真核生物）的碳同化。高达45%的细菌膜脂C被确定为直接来自CH（4），并在实验结束时，约。直接来自CH（4）的土壤碳中有50%保留在土壤中。结论这是首次估计土壤有机碳来源于CH（4），它是在湖泊中观察到的水平，具有高水平的底栖甲烷。SIS为新一代SIP研究开辟了道路，该研究旨在阐明在分子水平上在广泛的复杂环境和生物基质中的总C动态（掺入，营业额和衰变）。
RATIONALE Recent advances in stable isotope probing (SIP) have allowed direct linkage of microbial population structure and function. This paper details a new development of SIP, Stable Isotope Switching (SIS), which allows the simultaneous assessment of carbon (C) uptake, turnover and decay, and the elucidation of soil food webs within complex soils or sedimentary matrices. METHODS SIS utilises a stable isotope labelling approach whereby the (13)C-labelled substrate is switched part way through the incubation to a natural abundance substrate. A (13)CH(4) SIS study of landfill cover soils from Odcombe (Somerset, UK) was conducted. Carbon assimilation and dissimilation processes were monitored through bulk elemental analysis isotope ratio mass spectrometry and compound-specific gas chromatography/combustion/isotope ratio mass spectrometry, targeting a wide range of biomolecular components including: lipids, proteins and carbohydrates. RESULTS Carbon assimilation by primary consumers (methanotrophs) and sequential assimilation into secondary (Gram-negative and -positive bacteria) and tertiary consumers (Eukaryotes) was observed. Up to 45% of the bacterial membrane lipid C was determined to be directly derived from CH(4) and at the conclusion of the experiment ca. 50% of the bulk soil C derived directly from CH(4) was retained within the soil. CONCLUSIONS This is the first estimate of soil organic carbon derived from CH(4) and it is comparable with levels observed in lakes that have high levels of benthic methanogenesis. SIS opens the way for a new generation of SIP studies aimed at elucidating total C dynamics (incorporation, turnover and decay) at the molecular level in a wide range of complex environmental and biological matrices.