The metabolite dimethylsulfoxonium propionate extends the marine organosulfur cycle
The metabolite dimethylsulfoxonium propionate extends the marine organosulfur cycle
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DOI：
10.1038/s41586-018-0675-0
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发表时间：
2018-10
期刊：
影响因子：
64.8
通讯作者：
Kathleen Thume;Björn Gebser;Liangfu Chen;Nils Meyer;D. Kieber;G. Pohnert
中科院分区：
文献类型：
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作者：
Kathleen Thume;Björn Gebser;Liangfu Chen;Nils Meyer;D. Kieber;G. Pohnert
藻类产生大量的二甲基磺丙酸盐（DMSP），为有机硫循环提供燃料。在全球范围内，每年生产数吨这种硫物种，从而推动了基本过程和海洋食物网。DMSP的一个重要转化产物是二甲硫醚，它既可以排放到大气中，也可以氧化成二甲亚砜（DMSO）和其他产物。本文报道了一种结构异常的代谢物——丙酸二甲基亚砜（DMSOP），它是由几种产生DMSOP的微藻和海洋细菌合成的。与DMSP一样，DMSOP是一种低分子量的两性离子代谢物，同时携带一个带正电荷和一个带负电荷的官能团。同位素标记研究表明，DMSOP是由DMSP产生的，并且很容易被海洋细菌代谢成DMSO。在现场样品和藻类培养基中发现了接近纳摩尔量的DMSOP，因此，据我们所知，这是海洋环境中DMSO的一种先前未描述的生物源。从这一途径估计的每年海洋氧化硫产量在四元体范围内，与计算的二甲基硫化物向大气的通量相似。因此，这种亚砜铵代谢物是先前描述的海洋硫循环途径的关键代谢物。这些发现突出了DMSOP在海洋有机硫循环中的重要性。
Algae produce massive amounts of dimethylsulfoniopropionate (DMSP), which fuel the organosulfur cycle,. On a global scale, several petagrams of this sulfur species are produced annually, thereby driving fundamental processes and the marine food web. An important DMSP transformation product is dimethylsulfide, which can be either emitted to the atmosphere,or oxidized to dimethylsulfoxide (DMSO) and other products. Here we report the discovery of a structurally unusual metabolite, dimethylsulfoxonium propionate (DMSOP), that is synthesized by several DMSP-producing microalgae and marine bacteria. As with DMSP, DMSOP is a low-molecular-weight zwitterionic metabolite that carries both a positively and a negatively charged functional group. Isotope labelling studies demonstrate that DMSOP is produced from DMSP, and is readily metabolized to DMSO by marine bacteria. DMSOP was found in near nanomolar amounts in field samples and in algal culture media, and thus represents—to our knowledge—a previously undescribed biogenic source for DMSO in the marine environment. The estimated annual oceanic production of oxidized sulfur from this pathway is in the teragram range, similar to the calculated dimethylsulfide flux to the atmosphere. This sulfoxonium metabolite is therefore a key metabolite of a previously undescribed pathway in the marine sulfur cycle. These findings highlight the importance of DMSOP in the marine organosulfur cycle.