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Farmer dissertation final.pdf (2.66 MB)

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Coordination of Carbon Dioxide and Nitrogen Metabolism in Rhodobacter sphaeroides

Farmer, Ryan Michael
http://rave.ohiolink.edu/etdc/view?acc_num=osu1365519943

Abstract Details

2013, Doctor of Philosophy, Ohio State University, Microbiology.
Studies of metabolism usually characterize a system in isolation without a whole-cell focus on interactions with other metabolic pathways. In this work, two different metabolic pathways of the nonsulfur purple bacterium Rhodobacter sphaeroides were studied simultaneously in vivo to determine their influence upon each other. Rb. sphaeroides is capable of nitrogen fixation via nitrogenase catalysis and carbon dioxide fixation via the Calvin-Benson-Bassham (CBB) cycle. When the CBB cycle was inactivated through gene deletions, strains developed that deregulated nitrogenase. Genomic sequencing and comparative analyses of these mutant strains revealed multiple mutations that could account for the nitrogenase active phenotype. A mutation in the gene that encodes for glutamine synthetase and another in the gene that encodes for one subunit of nitrogenase were shown be sufficient to derepress nitrogenase synthesis and to affect its activity, respectively. Further studies of nitrogenase regulation led to the observation that the N-terminal GAF domain of the transcriptional regulator of nitrogenase, NifA, contributed to its post-translational response to cellular nitrogen status. Finally, the reciprocal response of the CBB cycle to nitrogenase activity was investigated determining that the expression of the genes of the CBB cycle was repressed when nitrogenase was active. The CBB enzyme phosphoribulokinase was found to mediate this repression. This study thus explored the coordination of carbon dioxide and nitrogen metabolism in Rb. sphaeroides.
F. Robert Tabita (Advisor)
Birgit Alber (Committee Member)
Charles Daniels (Committee Member)
Joseph Krzycki (Committee Member)
108 p.
Microbiology
Rhodobacter sphaeroides; metabolism; nitrogenase; CBB cycle

Recommended Citations

Citations

  • Farmer, R. M. (2013). Coordination of Carbon Dioxide and Nitrogen Metabolism in Rhodobacter sphaeroides [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365519943

    APA Style (7th edition)

  • Farmer, Ryan. Coordination of Carbon Dioxide and Nitrogen Metabolism in Rhodobacter sphaeroides. 2013. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1365519943.

    MLA Style (8th edition)

  • Farmer, Ryan. "Coordination of Carbon Dioxide and Nitrogen Metabolism in Rhodobacter sphaeroides." Doctoral dissertation, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365519943

    Chicago Manual of Style (17th edition)

osu1365519943
869
© 2013, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.