EAGER: Diatom Programmed Cell Death at Single-Cell Resolution

EAGER：单细胞分辨率下的硅藻程序性细胞死亡

• 批准号: 2029738
• 负责人: Monica Orellana
• 金额: $ 29.97万
• 依托单位: Institute for Systems Biology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2023-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2029738&HistoricalAwards=false
• 关键词: EAGER; Diatom; Programmed; Cell; Death

Diatoms are important primary producers in sunlit oceans and lakes across the globe. They are key players in spring phytoplankton blooms, which in turn support food webs that include productive fisheries. In addition, these photosynthetic diatom cells are known to capture enormous amounts of carbon, which are exported to depth as blooms die off. In oceanic systems, this process effectively removes carbon from the atmosphere for thousands of years. However, the biological mechanisms that lead to carbon sequestration, the transfer of carbon from the atmosphere into the deep ocean, are not well understood. As diatom populations reach the end of the bloom cycle, individual cells start to deteriorate and undergo cell death. The collapse of diatom populations is regarded as a critical point (or tipping point), which can be predicted by understanding the genetic activity of the population. This project seeks to elucidate how environmental change influences diatom cell-death processes. A mechanistic understanding of these cellular processes will elucidate how climate change could alter carbon-removal from the atmosphere and affect ocean productivity. The knowledge and methods developed during this study are applicable across organisms from all domains of life. The broader impacts of this project are focused on high school education and new ideas and approaches for three-dimensional learning opportunities in support of Next Generation Science Standards (NGSS). Specifically, researchers are working with high school educators and partners to teach concepts of systems approaches, tipping points, and carbon sequestration in the marine environment through educational modules.The goal is to determine the structure of diatom populations during the transition of actively growing cells towards population collapse by identifying the point of commitment (tipping point) at the level of individual cells. The model system is the diatom, Thalassiosira pseudonana, which is widespread and a common bloom-forming species. The random decision process of individual diatom cells is being characterized by establishing a genome-wide gene expression space through the physical and biochemical characterization of the cells. Implementation of the project is focused on measuring the phenotypic responses in the diatom to environmental factors including severe stress. Transcriptomic analyses during the transition of cell proliferation towards culture collapse include bulk (RNA-Seq) and single-cell (scRNA-Seq) high-throughput sequencing. Using a systems biology approach, the genetic information obtained from the samples is incorporated into predictive models to identify genetic transitions that occur prior to population collapse. The systems approach can detect changes in transcriptomic state that precede a critical point in the cell death process leading to predictions of how diatoms respond to environmental change. This work opens new vistas for the elucidation of mechanistic pathways of diatom cell populations.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.

硅藻是全球阳光充足的海洋和湖泊的重要初级生产者。它们是春季浮游植物水华的关键参与者，这反过来又支持包括生产性渔业在内的食物网。此外，众所周知，这些光合作用的硅藻细胞可以捕获大量的碳，随着水华的消亡，这些碳被输出到深海。在海洋系统中，这一过程有效地消除了大气中的碳，持续了数千年。然而，导致碳封存的生物机制，即碳从大气转移到深海的机制，还没有被很好地理解。随着硅藻种群达到开花周期的末期，单个细胞开始退化并经历细胞死亡。硅藻种群的崩溃被认为是一个临界点(或临界点)，可以通过了解种群的遗传活动来预测。这个项目试图阐明环境变化如何影响硅藻细胞死亡过程。对这些细胞过程的机械理解将阐明气候变化如何改变大气中的碳去除并影响海洋生产力。在这项研究中开发的知识和方法适用于生命各个领域的生物体。该项目的更广泛影响集中在高中教育和支持下一代科学标准(NGSS)的三维学习机会的新想法和新方法上。具体地说，研究人员正在与高中教育工作者和合作伙伴合作，通过教育模块教授海洋环境中系统方法、临界点和碳固存的概念。目标是通过在单个细胞水平上确定承诺点(临界点)，确定活跃生长的细胞向种群崩溃过渡期间硅藻种群的结构。模式系统是分布广泛、常见的水华形成物种--假海藻。单个硅藻细胞的随机决策过程是通过对细胞的物理和生化特征来建立全基因组的基因表达空间。该项目的实施重点是测量硅藻对包括严重胁迫在内的环境因素的表型反应。从细胞增殖到细胞崩溃的转录学分析包括批量(RNA-Seq)和单细胞(scRNA-Seq)高通量测序。使用系统生物学方法，从样本中获得的遗传信息被合并到预测模型中，以识别在种群崩溃之前发生的遗传转变。系统方法可以检测细胞死亡过程中临界点之前转录状态的变化，从而预测硅藻对环境变化的反应。这项工作为阐明硅藻细胞种群的机制途径开辟了新的前景。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。