Life Sciences Commons^™

Utilizing Earth's Microbiology To Develop The Framework For A Manufactured Martian Nitrogen Cycle, Kyle Valgardson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

History has shown us that space travel is a complicated activity not to be taken lightly. Extended missions such as those that would accompany a manned mission to Mars are guaranteed to have increased complexity and require creative solutions to problems we likely take for granted. One such issue is how to supply the necessary amount of nitrogen to the astronauts to keep them alive. Nitrogen is an essential component to life on Earth as most biological molecules, such as protein and DNA, contain a significant amount of it. Most organisms have to get it from what they eat, but …

The Nifz Accessory Protein Has An Equivalent Function In Maturation Of Both Nitrogenase Mofe Protein P-Clusters, Emilio Jimenez-Vicente, Zhi-Yong Yang, Julia S. Martin Del Campo, Valarie L. Cash, Lance C. Seefeldt, Dennis R. Dean

Chemistry and Biochemistry Faculty Publications

The Mo-dependent nitrogenase comprises two interacting components called the Fe protein and the MoFe protein. The MoFe protein is an α₂β₂ heterotetramer that harbors two types of complex metalloclusters, both of which are necessary for N₂reduction. One type is a 7Fe-9S-Mo-C-homocitrate species designated FeMo-cofactor, which provides the N₂-binding catalytic site, and the other is an 8Fe-7S species designated the P-cluster, involved in mediating intercomponent electron transfer to FeMo-cofactor. The MoFe protein's catalytic partner, Fe protein, is also required for both FeMo-cofactor formation and the conversion of an immature form of P-clusters to the …

Nutrient Acquisition Strategies Augment Growth In Tropical N2‐Fixing Trees In Nutrient‐Poor Soil And Under Elevated Co2, Megan K. Nasto, Klaus Winter, Benjamin L. Turner, Cory C. Cleveland

Ecology Center Publications

Tropical forests play a dominant role in the global carbon (C) cycle, and models predict increases in tropical net primary productivity (NPP) and C storage in response to rising atmospheric carbon dioxide (CO₂) concentrations. The extent to which increasing CO₂ will enhance NPP depends in part on the availability of nitrogen (N) and phosphorus (P) to support growth. Some tropical trees can potentially overcome nutrient limitation by acquiring N via symbiotic dinitrogen (N₂) fixation, which may provide a benefit in acquiring P via investment in N‐rich phosphatase enzymes or arbuscular mycorrhizal (AM) fungi. We conducted …

Electron Transfer To Nitrogenase In Different Genomic And Metabolic Backgrounds, Saroj Poudel, Daniel R. Colman, Kathryn R. Fixen, Rhesa N. Ledbetter, Yanning Zheng, Natasha Pence, Lance C. Seefeldt, John W. Peters, Caroline S. Harwood, Eric S. Boyd

Chemistry and Biochemistry Faculty Publications

Nitrogenase catalyzes the reduction of dinitrogen (N₂) using low-potential electrons from ferredoxin (Fd) or flavodoxin (Fld) through an ATP-dependent process. Since its emergence in an anaerobic chemoautotroph, this oxygen (O₂)-sensitive enzyme complex has evolved to operate in a variety of genomic and metabolic backgrounds, including those of aerobes, anaerobes, chemotrophs, and phototrophs. However, whether pathways of electron delivery to nitrogenase are influenced by these different metabolic backgrounds is not well understood. Here, we report the distribution of homologs of Fds, Flds, and Fd-/Fld-reducing enzymes in 359 genomes of putative N₂ fixers (diazotrophs). Six distinct lineages …

A Comparative Study Of The Structural Features And Kinetic Properties Of The Mofe And Vfe Proteins From Azotobacter Vinelandii, Miguel Alejandro Pabon Sanclemente

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Biological nitrogen fixation is accomplished in the bacterium Azotobacter vinelandii by means of three metalloenzymes: The molybdenum, vanadium, and iron-only nitrogenase. The knowledge regarding biological nitrogen fixation has come from studies on the Mo-dependent reaction. However, the V- and Fe-only-dependent reduction of nitrogen remains largely unknown.

By using homology modeling techniques, the protein folds that contain the metal cluster active sites for the V- and Fe-only nitrogenases were constructed. The models uncovered similarities and differences existing among the nitrogenases regarding the identity of the amino acid residues lining pivotal structural features for the correct functioning of the proteins. These differences, …

Fire-Decay: Interactive Roles Regulating Wood Accumulation And Soil Development In The Northern Rocky Mountains, A. E. Harvey, M. J. Larsen, M. F. Jurgensen

Aspen Bibliography

Decay and fire play interactive roles in recycling wood and other organic materials in forest ecosystems, and contribute to the development of high quality soils in the Northern Rocky Mountains. Decayed wood, charcoal, and other decomposed organic matter are the principal media for ectomycorrhizal and nonsymbiotic nitrogen fixing microbes. The activities of these microbes are critical to the growth of forest trees. The balance between decay and fire, as it affects the amount, distribution, and type of organic matter, controls the ability of forest soils to support the growth of trees.

Nitrogen Fixation In Arid Western Soils, Robert Charles Rychert

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen fixation by blue-green algae-lichen crusts from South Curlew Valley, Utah, in the Great Basin Desert, was studied using the acetylene reduction technique. A molar ratio of 3 moles C₂H₄ produced/mole of N₂ fixed was used to estimate nitrogen (N₂) fixation by acetylene reduction. Nostoc was found to be present in many of the lichen thalli examined microscopically. Crust nitrogen fixation decreased rapidly below -1/3 bar pressure (water potential) which indicated that nitrogen fixation occurs only when the crust is wet. This would suggest that most of the crust nitrogen fixation in the Great …

Production And Nitrogen Content Of Herbage In A Silverberry (Elaeagnus Commutata) Community Compared To Adjacent Grassland And Forest Communities, G.L. Whysong, A.W. Bailey

Aspen Bibliography

No abstract provided.