Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Non-target effects of a novel invasive species management strategy: benthic invertebrate responses to lake trout embryo suppression in Yellowstone Lake, Wyoming(Montana State University - Bozeman, College of Letters & Science, 2020) Briggs, Michelle Anne; Chairperson, Graduate Committee: Lindsey Albertson; Lindsey K. Albertson, Dominique R. Lujan, Lusha M. Tronstad, Hayley C. Glassic, Christopher S. Guy and Todd M. Koel were co-authors of the article, 'Carcassd deposition to suppress invasive lake trout causes differential mortality of two common benthic invertebrates in Yellowstone Lake, Wyoming' in the journal 'Fundamental and applied limnology' which is contained within this thesis.; Lindsey K. Albertson, Dominique R. Lujan, Lusha M. Tronstad, Hayley C. Glassic, Christopher S. Guy and Todd M. Koel were co-authors of the article, 'Non-target effects of a novel suppression technique for invasive fishes: responses of benthic invertebrate communities' submitted to the journal 'Ecological applications' which is contained within this thesis.Invasive species threaten native biodiversity and ecosystem function, and suppression is often required to reduce these effects. However, invasive species management actions can cause harmful, unintended consequences for non-target taxa. In Yellowstone Lake, Wyoming, invasive lake trout (Salvelinus namaycush) have reduced abundance of the native Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), decreasing availability of an important food source for aquatic and terrestrial predators. Gillnets are used to suppress adult lake trout, and the lake trout carcasses are then deposited onto spawning sites in the littoral zone to cause embryo mortality by reducing dissolved oxygen concentrations as they decay. However, this management action may have non-target effects on organisms in the lake, including benthic invertebrates, which comprise a large portion of native trout diets. Some taxa of invertebrates may benefit from the addition of nutrients to the littoral zone, while other taxa may experience mortality in response to low dissolved oxygen conditions caused by carcass decay. We conducted two field experiments to understand how carcass treatment affects benthic invertebrates in Yellowstone Lake. First, we conducted an in situ experiment with individual invertebrates housed in small chambers covered by carcasses to determine if carcass treatment causes mortality of hypoxia-tolerant amphipods and hypoxia-sensitive caddisflies. We found that carcass treatment caused increased mortality in caddisflies but not amphipods. Second, we conducted a field experiment to investigate how carcass treatment affects invertebrate communities when applied at entire spawning sites. We also compared invertebrate communities at cobble-dominated lake trout spawning sites to macrophyte-dominated sites to determine if carcass treatment could alter food web dynamics at a lake-wide scale. We found that carcass treatment causes non-target effects on benthic invertebrates, specifically reducing immobile taxa, hypoxia-sensitive taxa, and Chironomidae, and altering community structure. Areas dominated by macrophytes had more abundant and larger invertebrates than spawning sites. Due to the small spatial extent of spawning sites and the higher abundance of invertebrates at other habitats in the lake, we conclude carcass treatment can have localized non-target effects at a local scale but is unlikely to alter food-web dynamics at a lake-wide scale.Item Effects of hydraulic loading on nitrification and denitrification processes in a two-stage, vertical flow treatment wetland at Bridger Bowl Ski Area(Montana State University - Bozeman, College of Engineering, 2020) Panighetti, Robert Arthur; Chairperson, Graduate Committee: Otto SteinA pilot-scale two-stage vertical flow treatment wetland (VFTW) at the Bridger Bowl Ski Area was used to evaluate the influence of hydraulic loading rate on COD removal, nitrification, and denitrification in the system. Hydraulic loading rates ranged between 36 cm/d to 60 cm/d over system years 2018 and 2019. Total nitrogen loading (sum of NH 4+ and NO 3-) ranged from 12 g/m 2d to 65 g/m 2d, and COD loading ranged from 58 g/m 2d to 172 g/m 2d. The system effectively removed COD in both years, with removals of 95% and 96% for influent COD concentrations of 555 mg/L and 607 mg/L, respectively. Influent total nitrogen was 141 mg/L in 2018 and 105 mg/L in 2019, and removals were 67% and 54%, respectively. At a hydraulic loading rate of 60 cm/d, COD removal declined in the first stage and ammonium removal declined in the second stage. At lower hydraulic loading rates (up to 48 cm/d), removal of COD, ammonium and nitrate increased in a consistent pattern with increased mass loading of the respective contaminant, suggesting a maximum hydraulic loading rate limit between 48 and 60 cm/d. The effect of hydraulic loading cannot be completely separated from mass loading of a contaminant, likely influenced by the level of partial saturation within the first stage and the recycle ratio; neither were varied in this study. A key limiting factor is hydraulic overload to the first stage, limiting removal of COD which interfered with nitrification in the second stage. A multivariate model for ammonium removal in the second stage predicts increased ammonium removal with increasing ammonium load but decreasing COD load. Despite operational performance variation the system met applicable discharge requirements, reinforcing the ability of a VFTW system to perform secondary wastewater treatment, even for high-strength wastewater and in cold climates.Item Proteomics analysis of the metabolic transition between aerobic and anaerobic conditions in Escherichia coli(Montana State University - Bozeman, College of Letters & Science, 2019) Refai, Mohammed Yahya; Chairperson, Graduate Committee: Brian Bothner; Nina Paris, Hunter Fausset, Monika Tokmina Lukaszewska were co-authors of the article, 'Proteomics analysis of the transition between aerobic and anaerobic growth conditions in Escherichia coli' submitted to the journal 'Biochimica et biophysica acta' which is contained within this dissertation.As a facultative anaerobe, Escherichia coli has the ability to grow in anaerobic and aerobic environments. Despite detailed characterizations of this model organism in the presence and absence of oxygen, an in-depth understanding of changes to the proteome during transitions from aerobic to anaerobic growth is lacking. This thesis work focuses on elucidating how protein thiol oxidation and reduction change during a facultative anaerobe's transition from aerobic to anaerobic growth conditions, and pathways of thiol-mediated cell signaling. Redox driven changes in cysteine oxidation involved in signaling are referred to as 'thiol switches'. These modulate diverse biological activities ranging from gene expression and protein synthesis to environmental stress response. Surprisingly, little is known about the role of thiol switches during microbial transitions from aerobic and anaerobic growth conditions. To explore this uncharted territory, a mass-spectrometry (MS)-based proteomics workflow was developed and refined. Following extensive protocol optimization for high-throughput MS data processing, normalization, and pattern matching, the analytical pipeline was fine-tuned for the specific proteome-wide analysis of cysteine chemical modifications in E. coli. The approach was based on open-source software and publicly accessible databases, creating a transparent, reproducible, and easily sharable proteomics approach. Herein, the redox state and chemical forms of protein-based thiol switches in E. coli were characterized over time as the bacterium reversibly transitioned between aerobic and anaerobic growth conditions. Unexpectedly, differential alkylation analysis of cysteine-containing E. coli proteins revealed a higher degree of protein thiol oxidation under anaerobic growth conditions, a result not reported for E. coli or any other facultative anaerobe. Our proteome-wide analysis also revealed that cysteine redox potentials vary widely, and several specific E. coli proteins contain highly reactive thiols. These findings provide strong evidence for thiol-based signaling in E. coli in response to environmental changes such as aerobic to anaerobic growth transitions. Characterization of specific redox switches underlying metabolic changes associated with oxygen availability has uncovered a previously unknown E. coli cell signaling mechanism. Since transitioning between aerobic and anaerobic environments is associated with bacterial virulence, this work opens new avenues to target pathogenic facultative anaerobes and to develop novel thiol-based antibacterial therapies.Item Spatiotemporal mapping of oxygen in model porous media biofilms using 19 F magnetic resonance oximetry(Montana State University - Bozeman, College of Engineering, 2019) Simkins, Jeffrey William; Chairperson, Graduate Committee: Philip S. Stewart and Joseph D. Seymour (co-chair); Philip S. Stewart and Joseph D. Seymour were co-authors of the article, 'Spatiotemporal mapping of oxygen in a microbially-impacted packed bed using 19 F nuclear magnetic resonance oximetry' in the journal 'The journal of magnetic resonance' which is contained within this dissertation.; Philip S. Stewart, Sarah L. Codd and Joseph D. Seymour were co-authors of the article, 'Non-invasive imaging of oxygen concentration in a complex in vitro biofilm infection model using 19 F MRI: persistence of an oxygen sink despite prolonged antibiotic therapy' submitted to the journal 'Magnetic resonance in medicine' which is contained within this dissertation.; Philip S. Stewart and Joseph D. Seymour were co-authors of the article, 'Microbial growth rates and local external mass transfer resistance in a porous bed biofilm system measured by 19 F magnetic resonance imaging of structure, oxygen concentration, and flow velocity' submitted to the journal 'Biotechnology and bioengineering' which is contained within this dissertation.Biofilms, microbial aggregates anchored to a surface using a sticky matrix of metabolic products called extracellular polymeric substances (EPS), are the dominant form of bacterial life and are widespread in nature, from glaciers to hot springs. The transition from the planktonic state to a biofilm is associated with striking changes to microbial phenotype which confer unique, biofilm-specific properties to resident cells that have important implications for medicine, industry, and environmental study. Many of these properties are caused in large part by oxygen transport limitation, which arises due to restriction of fluid flow in cell aggregates and consumption of oxygen for respiration. The balance of reactive and diffusive processes establishes strong spatial gradients in oxygen concentration which lead to profound spatial heterogeneity in bacterial species composition, growth yield, antimicrobial susceptibility, and reaction kinetics, among other traits. However, despite the importance of oxygen gradients in a host of highly-relevant biofilm phenomena, quantification of oxygen profiles in biofilms is difficult, both in the field and the lab, with the gold standard of measurement, the microelectrode, having significant limitations. 19 F Nuclear Magnetic Resonance (NMR) oximetry, a magnetic resonance-based technique for oxygen quantification that has been used to characterize oxygen usage in blood tissues and tumors, exploits the linear dependence of spin-lattice relaxation rate R 1 on local oxygen partial pressure for fluorine nuclei in perfluorocarbon (PFC) phases. In the current work, we apply 19 F NMR oximetry to a model packed bed biofilm system to generate novel insights into microbial oxygen usage and to introduce a complimentary oximetry tool for biofilm experimenters. We develop methodology for the introduction and fixation of a fluorinated oxygen sensor to facilitate long-term oxygen monitoring. We use 19 F oxygen distribution measurements in compliment to traditional NMR methods to correlate fluid flow with growth rate, generate spatial maps of oxygen utilization rate, identify differences in oxygen utilization behavior between different species, characterize infection persistence during antibiotic therapy, mathematically model macroscale oxygen sink development, and quantify local mass transfer phenomena.Item Management of heated high-flow nasal cannula with preterm and term neonates(Montana State University - Bozeman, College of Nursing, 2018) Belling, Nicole LeAnn; Chairperson, Graduate Committee: Jennifer SofieThis project addressed the need for education on using heated high-flow nasal cannula (HHFNC) on term and preterm neonates at a rural, centrally located hospital. The education needs were found in a two-part process: assessing the current special-care-nursery (SCN) nurses' knowledge on management of HHFNC and reviewing the current protocol for clarification. The nurses' understanding was assessed by using a survey that was quantitatively analyzed, and which identified two areas needing improvements: assessing the neonate when on HHFNC and education on the consequences of poor management of HHFNC. Survey data was used for an educational service on HHFNC provided by the Seattle Children's Respiratory Therapy (RT) manager. This seminar was provided to the SCN nurses, pediatricians, and RT department at the rural, centrally located hospital. Along with the seminar, a presentation was given by the author that reviewed the results of the survey and how to find and use the current policy.Item Development of an economic, mobile, dual oxygen and pH sensor(Montana State University - Bozeman, Graduate School, 2016) Hall, Jacqueline Paige; Chairperson, Graduate Committee: Peggy Taylor.Optical pH and oxygen sensors have various advantages over Clark amperometric oxygen electrodes, including portability and utility in aqueous environments unsuitable for the Clark electrode. The goal of this study was to affordably develop a dual pH and oxygen-sensing probe that could be used in a variety of settings. This study resulted in the development of the oxygen-sensing component of such a device. This component consisted of Platinum (II)-meso-tetra (2,3,4,5,6-pentafluorophenyl) porphyrin (PtTFPP) suspended in a polystyrene-based matrix. A 405 nm LED excited the PtTFPP phosphorescence and a Hamamatsu Digital Color Sensor S11012-01CR recorded the resultant emission intensities of the porphyrin. A code was written for an Arduino Uno ® microcontroller, to control the LED and color sensor, while recording the appropriate data. The oxygen-sensing component showed expected oxygen sensitivity during oxygen depletion studies.Item Temperature effects on the oxygen consumption during development of Aulocara elliotti (Thomas)(Montana State University - Bozeman, College of Agriculture, 1966) Laine, Inez IleneItem Hyperthermal reactions of O(p3sP) with hydrogen and methane(Montana State University - Bozeman, College of Letters & Science, 2004) Garton, Donna Joan; Chairperson, Graduate Committee: Lee SpanglerHyperthermal reactions of O(3P) occur at the surfaces and in the exhaust gases of spacecraft that travel through the residual atmosphere of the Earth at high altitudes (200-600 km). These reactions may degrade materials through oxidation and erosion, or they may yield internally excited reaction products which emit radiation and contribute to the “signature” of a rocket plume. Crossed-beams experiments were used to study model reactions of O(3P) with H2, D2, CH4, and CD4 at center-of-mass collision energies in the range 8-75 kcal mol^-1. Interpretation of the experimental results has been strengthened by theoretical calculations carried out by collaborators. A study of the OH scattered flux as a function of collision energy has led to the determination of an experimental excitation function in the threshold region for the O(3P)+H2 → OH+H reaction. The experimental excitation function clearly matched the theoretical prediction, which confirmed that the laser-detonation source produces O(3P) atoms. The excitation function for the O(3P) + H2 reaction and the dynamics of the O(3P) + D2 reaction, observed experimentally for the first time, demonstrate that these reactions proceed mainly on triplet potential energy surfaces, with little or no intersystem crossing. Experiments on the reactions of O(3P) with methane have revealed a previously unobserved reaction pathway, which involves H-atom elimination: O(3P) + CH4 → OCH3 + H. The excitation function for this reaction has been measured, and the reaction barrier has been determined to be ∼46 kcal mol^-1. In addition, the expected H-atom abstraction reaction, O(3P) + CH4 → CH3 + OH, has been observed, and the dynamics have been investigated. Theoretical calculations identify a triplet-singlet curve crossing below the triplet barrier for the H-atom elimination reaction, but the observed dynamics indicate reaction exclusively on the two lowest-lying triplet surfaces. While it remains to be seen whether intersystem crossing will affect the outcome of other reactions involving hyperthermal atomic oxygen, unknown reactions which have high barriers are likely to be common in extreme environments such as low-Earth orbit, where spacecraft surfaces and exhaust gases suffer high-energy collisions with ambient atomic oxygen.Item Assessment of air separation technologies for the recovery of oxygen for use in hypersonic flight(Montana State University - Bozeman, College of Engineering, 1997) Binau, Nathan JeremiahItem Studies of the action of molecular singlet oxygen on proteins and amino acids(Montana State University - Bozeman, College of Letters & Science, 1974) Fischer, James Ross