In vivo DMSP‐biosynthesis measurements using stable‐isotope incorporation and proton‐transfer‐reaction mass spectrometry (PTR‐MS)
In vivo DMSP‐biosynthesis measurements using stable‐isotope incorporation and proton‐transfer‐reaction mass spectrometry (PTR‐MS)
复制标题
使用稳定同位素掺入和质子转移反应质谱 (PTR-MS) 进行体内 DMSP 生物合成测量
DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
J. Elzenga
中科院分区：
文献类型：
--
作者：
J. Stefels;J. Dacey;J. Elzenga
评估不同环境条件下二甲基磺基丙酸酯（DMSP）的周转率是准确模拟海洋硫循环的基础，DMSP是气候活性气体二甲基硫（DMS）的前体。目前的气相色谱方法只能提供作用于不同硫库的所有过程的净结果，无法测量通量，从而为推测周转过程的控制因素和幅度留下了空间。在这里，我们提出了一种新的方法，其中稳定的同位素添加（D2 O或NaH 13 CO 3）被用来跟踪在体内生产的DMSP。使用质子-反应-转移质谱仪（PTR-MS）监测氘或13 C掺入DMSP。开发了一个生长模型，以计算特定的DMSP合成速率的标记与未标记的DMSP随着时间的推移的质量比的进展。我们的方法使用分子质量比，而不是测量掺入的同位素的量。这种方法的优点在于，同位素添加对质量比变化的影响被标记物在分子内可以占据的位置的数量放大。该方法的应用在普遍存在的DMSP生产者Emiliania huxleyi的培养物中得到了证明，并在2004年7月期间进一步开发用于来自马尾藻海的水的短期孵育研究。在0.05 ~ 0.2 d−1之间可以测量到非常低的比合成速率。该方法是第一个测量体内DMSP生产率的方法。它相对容易应用，灵敏度高，也可适用于其他生物源化合物。
Assessing turnover rates of dimethylsulfoniopropionate (DMSP), precursor of the climate‐active gas dimethylsulfide (DMS), under different environmental conditions is fundamental to accurately modeling the marine sulfur cycle. Current gas chromatographic methods only provide net results of all processes acting on the different sulfur pools and are unable to measure fluxes, leaving room for speculation on the controlling factors and magnitudes of turnover processes. Here we present a new method in which stable isotope additions (D2O or NaH13CO3) are used to follow the in vivo production of DMSP. Incorporation of deuterium or 13C into DMSP was monitored using a proton‐reaction‐transfer mass spectrometer (PTR‐MS). A growth model was developed to calculate specific DMSP synthesis rates from the progress in mass ratio of labeled versus nonlabeled DMSP over time. Instead of measuring the amount of incorporated isotope, our method uses ratios of molecule masses. This approach has the advantage that the effect of the isotope addition on the change in mass ratio is amplified by the number of positions the label can occupy within the molecule. Application of the method was demonstrated in cultures of the ubiquitous DMSP producer Emiliania huxleyi and further developed for use in short‐time incubation studies with water from the Sargasso Sea during July 2004. Very low specific synthesis rates between 0.05 and 0.2 d−1 could be measured. The method is the first to measure in vivo DMSP production rates. It is relatively easy to apply, highly sensitive, and may also be applicable to other biogenic compounds.