High-Resolution Liquid Chromatography Tandem Mass Spectrometry Enables Large Scale Molecular Characterization of Dissolved Organic Matter
High-Resolution Liquid Chromatography Tandem Mass Spectrometry Enables Large Scale Molecular Characterization of Dissolved Organic Matter
复制标题
DOI：
10.3389/fmars.2017.00405
复制
发表时间：
2017-01-01
影响因子：
3.7
通讯作者：
Dorrestein, Pieter C.
中科院分区：
文献类型：
--
作者：
Petras, Daniel;Koester, Irina;Dorrestein, Pieter C.
溶解有机物（DOM）可以说是地球上最复杂的外代谢物之一，由数千种化合物组成，它们共同贡献了超过600 × 10（15）g的碳。这个水库主要是上层海洋的微生物食物网之间相互作用的产物，但数千年来发生的非生物过程也改变了许多分子。该储层中的化合物在确定无机储层和海洋生物圈之间的元素交换速率和程度方面发挥着重要作用，同时也介导微生物-微生物相互作用。因此，人们广泛地努力使用高分辨率分析方法来表征DOM，包括核磁共振光谱法（NMR）和质谱法（MS）。迄今为止，DOM中的分子信息主要通过根据精确质量计算分子式来获得。这种方法的优点是非目标性，可以访问DOM的固有复杂性。然而，分子结构仍然难以捉摸，最常用的仪器也很昂贵。最近，串联质谱法已被用于通过与库质谱的比较来更精确地识别DOM组分。在这里，我们描述了一个数据采集和分析工作流程，该工作流程扩展了高分辨率分析方法的全部功能，可用于访问适合电喷雾电离（ESI）MS的DOM分子的复杂性。（LC-MS/MS）和数据分析管道，其集成了来自提取离子色谱图（XIC）的峰提取，分子式计算和分子网络。这提供了更精确的结构表征。虽然只有大约1%的可检测DOM化合物可以通过公开的光谱库进行注释，但社区范围内参与填充和注释DOM数据集可以迅速提高注释率，应该得到广泛鼓励。我们的分析还确定了当前数据分析工作流程的缺点，这些缺点需要社区在未来加以解决。这项工作将为DOM的综合、非靶向分子分析奠定基础，与下一代测序、元蛋白质组学和物理数据一起，将为更全面地了解DOM在构建海洋生态系统中的作用铺平道路。
Dissolved organic matter (DOM) is arguably one of the most complex exometabolomes on earth, and is comprised of thousands of compounds, that together contribute more than 600 x 10(15) g carbon. This reservoir is primarily the product of interactions between the upper ocean's microbial food web, yet abiotic processes that occur over millennia have also modified many of its molecules. The compounds within this reservoir play important roles in determining the rate and extent of element exchange between inorganic reservoirs and the marine biosphere, while also mediating microbe-microbe interactions. As such, there has been a widespread effort to characterize DOM using high-resolution analytical methods including nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). To date, molecular information in DOM has been primarily obtained through calculated molecular formulas from exact mass. This approach has the advantage of being non-targeted, accessing the inherent complexity of DOM. Molecular structures are however still elusive and the most commonly used instruments are costly. More recently, tandem mass spectrometry has been employed to more precisely identify DOM components through comparison to library mass spectra. Here we describe a data acquisition and analysis workflow that expands the repertoire of high-resolution analytical approaches available to access the complexity of DOM molecules that are amenable to electrospray ionization (ESI) MS. We couple liquid chromatographic separation with tandem MS (LC-MS/MS) and a data analysis pipeline, that integrates peak extraction from extracted ion chromatograms (XIC), molecular formula calculation and molecular networking. This provides more precise structural characterization. Although only around 1% of detectable DOM compounds can be annotated through publicly available spectral libraries, community-wide participation in populating and annotating DOM datasets could rapidly increase the annotation rate and should be broadly encouraged. Our analysis also identifies shortcomings of the current data analysis workflow that need to be addressed by the community in the future. This work will lay the foundation for an integrative, non-targeted molecular analysis of DOM which, together with next generation sequencing, meta-proteomics and physical data, will pave the way to a more comprehensive understanding of the role of DOM in structuring marine ecosystems.