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.

地球在整个历史上都经历了重大的环境变化，这些变化影响了生活及其发展。我们对生命如何在不断变化的星球上发展的理解主要是基于对动植物化石的研究，这些研究揭示了宏观生物的丰富性和多样性的深刻变化。但是，在动物和植物生命的出现之前，古代的地球是由微生物的主导的，这些生物没有容易识别的结构化石。因此，在地球遥远的过去研究微生物寿命中是必要的替代方法。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是分子化石，可以为古代气候事件，大规模灭绝和整个地球历史的各种进化过渡提供重大见解。但是，对脂质生物标志物的适当解释取决于对当今现代系统中其生产的广泛理解。该项目将结合分子和生化方法来解决杰出的生物标志物问题，这些问题使对岩石记录中这些分子的解释混淆了。这些研究将使我们对生命如何应对地球历史上的戏剧性生态变化做出反应，并可以洞悉现代生物如何应对当今的长期大气和气候变化。该项目的更广泛的影响着重于开发基于询问的本科实验室课程，该课程将拟议的研究目标纳入课程中。分子地球生物学实验室课程将使学生体验完整的科学过程 - 从发展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，本课程将使学生从不同的科学背景暴露于地球生物学的跨学科性质。该建议还将为PI实验室中的不同背景研究机会提供来自不同背景的本科生。该项目将解决三种生物标志物不确定性，目的是提供实验证据以改善生物标志物的解释。其中包括确定在沉积岩石中检测到的孤儿生物标志物的潜在微生物来源，确定海绵固醇生物标志物假说的鲁棒性，并表征古细胞脂质的脂质，GDGT的合成。地球的历史标志着戏剧性的大气和气候波动的时期，极大地影响了地球的生物圈和地质。生物标志物脂质可以为这些互动提供一个窗口，这是该项目的目标是更好地了解控制脂质生物标志物的分布和保存的过程和来源。该奖项反映了NSF的法定任务，并被视为值得支持的支持。通过使用基金会的智力优点和更广泛影响的评论标准进行评估。

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