Redox Photochemistry in Genomes of Microorganisms

化学系的生命过程化学项目资助了犹他大学的辛西娅·巴罗斯博士。她的研究小组计划研究微生物的基因组如何适应环境压力。许多种类的植物、藻类和细菌已经适应了高温、盐、干旱或强烈的紫外线等极端条件下的生活，所有这些都会对细胞的DNA产生化学压力。其他生物，如珊瑚共生体虫黄藻（藻类的近亲），还没有适应压力，而海洋温度的上升正导致珊瑚“白化”，因为藻类是珊瑚的食物来源。该基金支持的研究调查了一种假设，即可以折叠成称为“g -四重体”的基序的DNA序列可能有助于生物体应对由温度升高和光合作用增加引起的氧化应激。参与这项工作的学生将学习环境的化学成分如何在生物体遗传密码的水平上影响细胞的化学成分。此外，PI正在开发一系列讲座，“超越沃森和克里克”，传达DNA变化对生命过程的重要性。为了解决为什么某些微生物，特别是藻类和嗜热细菌，在其基因组中具有密集的潜在g -四重体序列（PQS）的问题，将在模式藻类生物衣藻中开发报告质粒测定。合成改变的DNA序列被插入到报告基因的启动子序列中，基因表达将被监测为氧化应激的功能。此外，还将对热菌的PQS密度进行研究。氧化损伤位点将被映射到启动子区域和PQS位点上，以发现g -四重体序列、氧化损伤调控和对环境胁迫的适应性反应之间的相关性。这些研究有助于确定DNA中化学修饰的碱基，如8-氧鸟嘌呤，作为表观遗传标记的情况。该奖项反映了美国国家科学基金会的法定使命，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。

The Chemistry of Life Processes Program in the Division of Chemistry is awarding funding to Dr. Cynthia Burrows at the University of Utah. Her research team plans to investigate how the genomes of microorganisms adapt to environmental stress. Many species of plants, algae and bacteria have adapted to live under extreme conditions of heat, salt, drought or intense UV light, all of which place chemical stress on the cell's DNA. Other organisms, such as the coral symbiont zooxanthellae, a close cousin of algae, have not adapted to stress, and rising ocean temperatures are leading to coral 'bleaching' due to loss of their algae, a food source for the coral. Research supported by this grant investigates the hypothesis that sequences of DNA that can fold into a motif termed "G-quadruplex" may help the organism respond to oxidative stress caused by an increase in temperature and increased photosynthesis. Students involved in this work are to learn how the chemistry of the environment influences the chemistry of the cell at the level of the organism's genetic code. In addition, the PI is developing a series of lectures, "Beyond Watson and Crick," that communicate the importance of changes in the DNA to life processes.To address the question of why certain microorganisms, notably algae and thermophilic bacteria, have dense potential G-quadruplex sequences (PQS) in their genomes, a reporter plasmid assay is to be developed in the model algal organism Chlamydomonas. Synthetically altered DNA sequences is to be inserted into promoter sequences of a reporter gene, and gene expression will be monitored as a function of oxidative stress. In addition, the PQS density in Thermus bacteria is to be investigated. The sites of oxidative damage are to be mapped onto the promoter regions and PQS sites to discover correlations between G-quadruplex sequences, regulation of oxidative damage, and adaptive responses to environmental stress. These studies help define the circumstances under which chemically-modified bases in DNA, such as 8-oxoguanine, serve as epigenetic markers.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.