CAREER: The Carbon Concentrating Mechanism of the Deep-sea Hydrothermal Vent Chemolithoautotroph Thiomicrospira Crunogena

化能石自养细菌通过氧化硫化物、氨和铁等无机化合物来获取能量，并利用这些能量为二氧化碳和碳酸氢盐的固定提供动力。这些生物具有重要的生态和环境意义；例如，它们是热液喷口食物网的基础，在全球氮循环中起着关键作用，并使受矿山尾矿影响的地区酸化。它们的一些栖息地长期或偶尔具有低浓度的二氧化碳和碳酸氢盐，这使得在“低碳”条件下生长能力增强的生物具有明显的优势。我们有理由预测，许多趋化石自养生物具有广泛的适应能力，以应对“低碳”条件。热液喷口的化能岩石自养生物硫微螺旋藻（thiommicrospira crunogena）最近被证明具有“二氧化碳真空”的作用。它能够在极低浓度的碳酸氢盐和二氧化碳存在下快速生长，并且能够以某种方式用碳酸氢盐填充其细胞，以至于细胞内的碳酸氢盐浓度比外部高100倍。此外，T. crunogena的基因组最近已被测序，这将极大地促进发现负责其“二氧化碳吸尘”能力的基因。该项目的总体目标是生理学和遗传学表征T. crunogena将大量碳酸氢盐和二氧化碳“泵”入细胞的能力。为了实现这一目标，传统的生理方法和尖端的分子工具将被利用。化化岩石自养生物催化具有深远生态和地球化学意义的过程；了解它们如何应对明显的环境压力，将大大提高我们预测它们在原地活动的能力，以及它们如何受到大气二氧化碳浓度增加的影响。更广泛的影响这些研究目标在很大程度上依赖于基因组数据，这些数据是由参加K. Scott基因组学课程的本科生和研究生手工注释的。由于学生对这门课程的极大热情，以及基因组水平分析在生物学研究中的重要性日益增加，首席研究员打算将基因组学教育扩展到中学水平。教育部分的目标是：1。为中学科学教育工作者开设微生物基因组学暑期工作坊。每年夏季招收的20名教育工作者中，有5名将从少数族裔占主导地位的学校中选出。创建一个基于网络的界面，允许中学生与PI及其研究生和本科生研究人员互动，以了解更多关于微生物基因组学的知识。将QRT-PCR应用于高级微生物生理实验室。这种综合的研究和教育方法将产生对化学岩石自养生理学的基本见解，为未来环境样本的分析提供目标基因，并为解释其他微生物的基因组数据提供关键见解，并为中学生加入基因组学革命做好准备。

Chemolithoautotrophic bacteria obtain energy by oxidizing inorganic compounds such as sulfide, ammonia, and iron, and use this energy to power carbon dioxide and bicarbonate fixation. These organisms are of great ecological and environmental relevance; for example, they are the base of the food web at hydrothermal vents, occupy critical roles in the global nitrogen cycle, and acidify areas impacted by mine tailings. Some of their habitats have chronically or episodically low concentrations of carbon dioxide and bicarbonate, which puts organisms with an enhanced ability to grow under 'low carbon' conditions at a distinct advantage. It is reasonable to predict that many chemolithoautotrophs have extensive adaptations to cope with 'low carbon' conditions. The hydrothermal vent chemolithoautotroph Thiomicrospira crunogena has recently been demonstrated to act as a 'carbon dioxide vacuum'. It is capable of growing rapidly in the presence of vanishingly low concentrations of bicarbonate and carbon dioxide, and can somehow pack its cells with bicarbonate, to the point where the concentration of bicarbonate inside the cells is 100X higher than outside. Furthermore, T. crunogena's genome has recently been sequenced, which will greatly facilitate the discovery of the genes responsible for its 'carbon dioxide vacuuming' ability.The overall objective of this project is to physiologically and genetically characterize T. crunogena's ability to 'pump' vast quantities of bicarbonate and carbon dioxide into its cells. To meet this objective, both traditional physiological methods and cutting-edge molecular tools will be utilized. Chemolithoautotrophs catalyze processes of profound ecological and geochemical importance; developing an understanding of how they cope with an obvious environmental stressor will substantially enhance our capability to predict their activities in situ, and how they may be impacted by increasing concentrations of atmospheric carbon dioxide.Broader impactsThese research objectives rely heavily on genome data manually annotated by the undergraduate and graduate students enrolled in K. Scott's Genomics class. Spurred by the extraordinary enthusiasm of the students enrolled in this course, and by the growing importance of genome-level analyses in biological research, the principal investigator intends to expand genomics education to the secondary level. The objectives of the educational component are1. To create summer workshops in microbial genomics for secondary science educators. Five of the twenty educators enrolling per summer would be selected from schools with predominantly minority enrollment.2. To create a web-based interface allowing secondary students to interact with the PI and her graduate and undergraduate researchers to learn more about microbial genomics.3. To incorporate QRT-PCR into an upper-level Microbial Physiology Lab. This integrated approach to research and education will yield fundamental insights into chemolithoautotroph physiology, provide target genes for future analyses of environmental samples and key insights into the interpretation of genomic data from other microorganisms, and prepare secondary students to join the genomics revolution.