CAREER: Crossing over into the geochemical milieu: Using the molecular genomic record to inform the geologic biomarker record

职业：跨越地球化学环境：利用分子基因组记录为地质生物标记记录提供信息

• 批准号: 1752564
• 负责人: Paula Welander
• 金额: $ 64.74万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1752564&HistoricalAwards=false
• 关键词: CAREER; Crossing; over; into; geochemical

Earth has experienced significant environmental change throughout its history and these changes have impacted life and its evolution. Our understanding of how life has evolved on our changing planet is primarily based on studies of plant and animal fossils that have revealed profound changes in the abundance and diversity of macroscopic organisms. However, prior to the emergence of animal and plant life, the ancient Earth was dominated by microbial organisms that did not leave easily identifiable structural fossils. Thus, alternative approaches are necessary to study microbial life in the context of Earth's distant past. One such approach is to link molecules produced by modern day microbes to molecules preserved in sedimentary rocks. These biomarker molecules function as molecular fossils that can provide significant insight into ancient climatic events, mass extinctions, and various evolutionary transitions throughout Earth's history. However, the proper interpretation of lipid biomarkers is dependent on a broad understanding of their production in modern systems today. This project will use a combination of molecular and biochemical approaches to address outstanding biomarker questions that have confounded the interpretation of these molecules in the rock record. These studies will inform our understanding of how life has responded to dramatic ecological change throughout Earth's history and could provide insight into how modern organisms may respond to long-term atmospheric and climate changes today. The broader impacts of this project focus on developing an inquiry-based undergraduate laboratory course that incorporates the proposed research objectives into the curriculum. The Molecular Geomicrobiology Laboratory course will allow students to experience the full scientific process - from developing hypotheses to testing those hypotheses to preparing a manuscript to disseminate their findings. In addition, this course will expose students from diverse scientific backgrounds to the interdisciplinary nature of geobiology. This proposal will also provide undergraduate student from diverse backgrounds research opportunities in the laboratory of the PI.This project will address three biomarker uncertainties with the goal of providing experimental evidence to allow for improved biomarker interpretations. These include identifying potential microbial sources for orphan biomarkers detected in sedimentary rocks, determining the robustness of the sponge sterol biomarker hypothesis, and characterizing the synthesis of the paleotemperature proxy lipids, GDGTs, in archaea. Earth's history is marked with periods of dramatic atmospheric and climate fluctuations that greatly impacted the Earth's biosphere and geosphere. Biomarker lipids can provide a window into those interactions and it is the goal of this project to generate a better understanding of the processes and sources that control the distribution and preservation of lipid biomarkers.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.

地球在其整个历史上经历了重大的环境变化，这些变化影响了生命及其进化。我们对生命如何在不断变化的地球上进化的理解主要基于对植物和动物化石的研究，这些化石揭示了宏观生物体丰度和多样性的深刻变化。然而，在动物和植物生命出现之前，古代地球是由微生物有机体主导的，没有留下容易识别的结构化石。因此，有必要采用其他方法来研究地球遥远过去背景下的微生物生命。其中一种方法是将现代微生物产生的分子与沉积岩中保存的分子联系起来。这些生物标志物分子作为分子化石，可以提供对古代气候事件，大规模灭绝和整个地球历史的各种进化转变的重要见解。然而，对脂质生物标志物的正确解释取决于对它们在当今现代系统中的产生的广泛理解。该项目将使用分子和生物化学方法的组合来解决突出的生物标志物问题，这些问题混淆了岩石记录中这些分子的解释。这些研究将为我们了解生命如何应对整个地球历史上巨大的生态变化提供信息，并可以深入了解现代生物如何应对当今长期的大气和气候变化。该项目的更广泛的影响集中在开发一个基于探究的本科实验室课程，将拟议的研究目标纳入课程。分子地质微生物学实验室课程将让学生体验完整的科学过程-从开发假设到测试这些假设，再到准备手稿以传播他们的发现。此外，本课程将使来自不同科学背景的学生接触到地球生物学的跨学科性质。该项目还将为来自不同背景的本科生提供在PI实验室进行研究的机会。该项目将解决三个生物标志物的不确定性，目的是提供实验证据，以改进生物标志物的解释。这些包括确定潜在的微生物来源的孤儿生物标志物在沉积岩中检测到，确定海绵甾醇生物标志物假设的鲁棒性，并表征合成的古温度代理脂质，GDGT，在古细菌。地球的历史以剧烈的大气和气候波动为标志，这些波动极大地影响了地球的生物圈和地圈。生物标志物脂质可以为这些相互作用提供一个窗口，该项目的目标是更好地了解控制脂质生物标志物分布和保存的过程和来源。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

GDGT cyclization proteins identify the dominant archaeal sources of tetraether lipids in the ocean

• DOI: 10.1073/pnas.1909306116
• 发表时间: 2019-10
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Z. Zeng;Xiao-Lei Liu;Kristen R Farley;Jeremy H. Wei;W. Metcalf;R. Summons;P. Welander