RECONSTRUCTING PAST ECOLOGIES USING PEPTIDOMICS

使用肽组学重建过去的生态学

基本信息

批准号：
2122895
负责人：
Richard Keil
金额：
$ 39.96万
依托单位：
University of Washington
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-15 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2122895&HistoricalAwards=false
关键词：
RECONSTRUCTING PAST ECOLOGIES USING PEPTIDOMICS

项目摘要

The project will try to understand what the ocean was like in the past by looking at proteins in mud found at the bottom of the ocean. When marine organisms die they sometimes sink to the bottom of the ocean and their carcasses accumulate in the mud. This happens even for very small organisms, and some of their proteins are left behind. Like the rings of a tree trunk, sediment at the bottom of the ocean slowly accumulates and acts as a recording of the past. The deeper you go into the sediment the older the proteins are. The study will extract protein from sediment that goes back about 150,000 years. The proteins will be sorted by the functions the proteins had when they were in the living organism, and by the organisms that they came from. The study should discover hundreds of ancient proteins. Those proteins will provide information about the types of organisms living in the past at that spot and what they were doing. Those data will make it possible to reconstruct the ecology of the past ocean. The study will use sediments from the Pacific coast of Mexico where conditions are good to preserve proteins, and where the community of microscopic organisms living in the past is expected to be dramatically different from today. The project will support a Mexican-American woman postdoc and a high school internship program. In that program three high school students from groups underrepresented in the earth sciences will be paired with undergraduate and grad student mentors. Past ocean environments are often evaluated using specific organic proxies that are linked to important oceanic processes such as primary production. A new tool for reconstructing the past ecology of the water column (e.g. estimating community structure and composition) is proposed. Peptides extracted from a well-characterized marine sediment that extends back into the Last Glacial Maximum will be used to reconstruct the past community ecology of the overlying water. Simultaneous assessment of the diagenetic status of extracted peptides provides a built-in measure of how much degradation has occurred, allowing for back-calculation of primary production. The development of new peptide-based biomarkers will allow for past oceanic conditions to be assessed in much greater ecological detail, thus enabling better prediction of future change. Peptides will be extracted from a well-characterized varved sediment core collected in the Eastern Tropical North Pacific along the Baja peninsula. A novel de novo-directed peptidomic approach based on computational analyses of resultant tandem mass spectra will be used to identify peptides in subsamples of the core from the Holocene and the LGM. These are believed to be among the first successful peptide extractions from marine sediments. The peptides to be evaluated include highly conserved peptides that are found only associated with photosynthesis but are universal across kingdoms. Because these peptides are universal but unique to autotrophs, they serve as a proxy for the total chloroplast (e.g. chlorophyll, primary production) of a sample. Peptides that identify other community functions such as nitrogen fixation and denitrification will also be sought. The overall peptide composition records a slice in time of the overlying water. The core has a well-constructed age model and has already been analyzed for biogenic silica and pigments, thus providing other measures to compare against. Modern samples of plankton and sinking particles collected at and near the ETNP core location will also be assessed. The intent is to develop a quantitative understanding of the paleo record that can be extracted from the peptides in the core and relate it back to the processes in the overlying water that deliver the signal to the sediment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目将试图通过查看海洋底部发现的泥浆中的蛋白质来了解过去的海洋。当海洋生物死亡时，它们有时会沉入海洋底部，尸体积聚在泥土中。即使对于很小的生物，也会发生这种情况，并且它们的某些蛋白质被遗留在后面。就像树干的戒指一样，海洋底部的沉积物也慢慢积聚并充当过去的记录。您进入沉积物越深，蛋白质年龄较大。这项研究将从约150，000年的沉积物中提取蛋白质。蛋白质将通过蛋白质在生物体中以及它们来自生物的生物时的功能进行分类。该研究应发现数百种古代蛋白质。这些蛋白质将提供有关过去在该地点及其在做什么的生物类型的信息。这些数据将使重建过去海洋的生态学成为可能。这项研究将使用墨西哥太平洋海岸的沉积物，那里的条件良好，可以保存蛋白质，而过去生活在过去的微观生物社区预计将与今天大不相同。该项目将支持墨西哥裔美国妇女博士后和高中实习计划。在该计划中，来自地球科学中代表性不足的小组的三名高中生将与本科和学生导师配对。过去的海洋环境通常使用与重要海洋过程（例如初级生产）相关的特定有机代理进行评估。提出了一种重建水柱过去生态的新工具（例如，估计社区结构和组成）。从特征良好的海洋沉积物中提取的肽延伸到最后一个冰川最大值将用于重建上覆水的过去社区生态。同时评估提取的肽的成岩成分状态提供了内置的量度，以衡量发生了多少降解，从而可以对初级生产进行后计。新的基于肽的生物标志物的开发将使过去的海洋条件得到更大的生态细节，从而更好地预测未来的变化。将从沿巴哈半岛东部热带北太平洋地区收集的良好特征的彩色沉积物芯中提取肽。基于所得串联质谱的计算分析，一种新颖的从头定向的肽组方法将用于从全新世和LGM中鉴定核心子样本中的肽。据信这些是海洋沉积物中首次成功提取的肽之一。要评估的肽包括高度保守的肽，这些肽仅与光合作用相关，但在整个王国之间是普遍的。由于这些肽是通用的，但在自养中是独有的，因此它们是样品总叶绿体（例如叶绿素，一级生产）的代理。还将寻求鉴定其他社区功能（例如固定氮和反硝化）的肽。总体肽组成记录了在上面的水的时间内切片。核心具有良好的年龄模型，并且已经对生物二氧化硅和颜料进行了分析，从而提供了其他措施以进行比较。还将评估在ETNP核心位置和附近收集的浮游生物的现代样品。目的是对古唱片进行定量理解，该记录可以从核心中的肽中提取，并将其与上上面的水中的过程联系起来，以将信号传递给沉积物。该奖项反映了NSF的法定任务，并通过评估该基金会的智力功能和广泛的影响来审查Criteria，并被认为是通过评估的支持。