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

University Of South Florida, Tampa FL

Investigators

Abstract

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 impacts These 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 are 1. 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.