RUI: Analysis of Intracellular Biogenic Sulfur Using micro-Raman Spectroscopy

生物源硫化合物，如二甲基硫醚（DMS）、其前体二甲基磺酰丙酸（DMSP）和二甲基亚砜（DMSO）及其大气氧化产物甲烷磺酸（MSA），是全球硫循环的重要组成部分，对全球气候产生重大影响。DMSP和DMSO在产生它们的生物体中的作用，以及它们在细胞内的浓度，人们知之甚少。据推测，DMSO在细胞内渗透调节、低温保护和清除活性氧中起作用，但其在浮游生物中的细胞内浓度仅为推测。为了更全面地了解生物硫化合物的生物地球化学特征，有必要对体内生物硫化合物的浓度进行定量测定。首席研究员已经开发了使用拉曼光谱对生物硫化合物进行定量分析的方法，该方法已导致DMSO的检测灵敏度为10 mM -远远低于其细胞内浓度的当前估计。这项研究将把这项技术扩展到DMSP。直接测定细胞内DMSP和DMSO，将使这些化合物在浮游植物中的作用得以研究。最后，利用野外采集的岩心，将测量海冰微环境中细胞内硫化合物以及分子阴离子的浓度。作为一个RUI项目，这项工作的成功完成将对南阿拉巴马大学化学系的本科教育产生重大影响，使本科生，特别是在科学领域代表性不足的少数民族接触到前沿研究。它将为他们的教育提供财政支持，并允许他们在期刊文章和技术会议上发表研究成果。与其他机构南极研究领域的科学家接触将使学生有机会与相关领域的研究人员互动，扩大他们的经验基础。

Biogenic sulfur compounds, such as dimethyl sulfide (DMS), its precursors dimethyl sulfoniopropionate (DMSP) and dimethyl sulfoxide (DMSO), and its atmospheric oxidation product, methane sulfonic acid (MSA), are important components of the global sulfur cycle that significantly impact global climate. The roles of DMSP and DMSO within the organisms that produce them, as well as their intracellular concentrations, are poorly understood. DMSO has been speculated to play a role in intracellular osmoregulation, cryoprotection and scavenging of reactive oxygen species, but its intracellular concentration in plankton has only been inferred. Quantitative measurement of the concentration of biogenic sulfur compounds in vivo is necessary to more completely understand their biogeochemistry. The principal investigator has developed methods for the quantitative analysis of biogenic sulfur compounds using Raman spectroscopy, which have resulted in the detection of DMSO with a sensitivity of 10 mM - far lower than the current estimates of its intracellular concentrations. The research will extend this technique to DMSP. The direct determination of the intracellular DMSP and DMSO, will allow the proposed roles of these compounds in phytoplankton to be investigated. Lastly, using field-collected cores, measurements will be made of the intracellular sulfur compounds as well as the concentration of molecular anions in the sea ice micro-environment. As an RUI project, successful completion of this work will have a substantial impact on undergraduate education in the Chemistry Department at the University of South Alabama, exposing undergraduates and, particularly, under-represented minorities in the sciences to cutting-edge research. It will provide financial support for their education and allow them to present research in journal articles and at technical meetings. Contacts with scientists in the field of Antarctic research at other institutions will give students the opportunity to interact with researchers in related fields, broadening their experience base.