Life Sciences Commons^™

The Role Of Hypoxia Inducible Factor-1 Alpha (Hif-1⍺) In Human Coronavirus Oc43 Infection, Olivia Faith Riffey

Masters Theses

The importance of altering host cell metabolism for promoting infection and propagation of coronaviruses highlights the intricate play between viruses and the cells they infect (1). Upregulation of the glycolytic pathway in host cells infected with coronaviruses was observed in single-cell RNAseq, although the mechanism(s) that mediate this effect are still being investigated(2). Hypoxia-inducible factor-1 alpha (HIF-1⍺) is a transcription factor that regulates many glycolytic enzymes. Recent studies have identified SARS-CoV-2 upregulation of HIF-1⍺, which suggests it may have an important role in virus production (3, 4). However, the exact role and physiological relevance of HIF-1⍺ during viral infection is …

The Impacts Of Tilled-In Biodegradable Plastic Mulch On Soil Microbial Communities, Corissa L. Martin

Masters Theses

Plastics mulch films are used in agriculture to help increase crop production by regulating soil water retention and soil temperature while also preventing weed growth. Despite these benefits, plastic mulches have led to higher levels of microplastic pollution as weathering occurs. In response to this issue, biodegradable plastic mulches (BDMs) have been introduced to help reduce plastic pollution as they are designed to be tilled into soil after each growing season to continue degradation. Degradation of these mulch films is dependent on climate and, in some areas, complete degradation can take years. Since some biodegradable plastic mulches are made of …

Pregnancy Influences On The Rumen Environment Of Angus Heifers Differing In Feed Efficiency, Miranda Gabrielle Martin

Masters Theses

With an expected increase in population by 2050, the demand for more animal protein will increase. To improve the sustainability of US cattle production, producers and researchers have historically focused on improving the feed efficiency of steers, producing a more marketable beef product. However, without a successful pregnancy, there would be no marketable animal to feed. The objective of this study was to examine the physiological changes that occur during pregnancy and their impact on the rumen microbial communities and the correlation to feed efficiency status in Angus heifers. Utilizing 17 cannulated Angus heifers, feed efficiency data was previously collected …

The Application Of Microbial Source Tracking To Aid In Site Prioritization For Remediation In Lower Michigan, John J. Hart

Masters Theses

Non-point source fecal pollution is a threat to both the environment and public health. Climate change, aging infrastructure, and intensified agricultural practices are predicted to accentuate this issue. In Michigan, due to the high instance of aging infrastructure and intensified agriculture, non-point source fecal pollution has caused many waterbodies to exceed the state standards posing a risk to recreational activities and source water. Due to this threat, there is an increased effort to identify and remediate these sources. My study focused on improving the identification of non-point source fecal pollution through a combination of culture-based and molecular fecal indicator bacteria …

Application Of Nitrate To An Anaerobic Subsurface Bioremediation, Cassie Marie Roberts

Masters Theses

"The highly contaminated subsurface matrix of the Baird and McGuire Superfund site is currently threatening the health and safety of the surrounding environment of Holbrook, MA. Contaminants of significant concern due to high concentration are inorganic arsenite and petroleum hydrocarbons, such as naphthalene. Parsons Corporation and the Massachusetts Department of Environmental Protection have implemented a bioremediation pilot to attempt to degrade the hydrocarbons and arsenic with the application of nitrate. The nitrate would act as an electron acceptor for biodegradation of the hydrocarbon contaminants, produce nitrite that would oxidize reduced iron, and iron oxides would sequester arsenic. Preliminary data showed …

Ecological Controls On Successional Patterns In Bloom-Forming Cyanobacteria, Kyla L. Hooker

Masters Theses

Harmful algal blooms are widespread in lake ecosystems but the ecological factors underlying their formation and maintenance are poorly understood. We revisit classical ecological theories which characterize and evaluate contrasting bottom-up and top-down influences on the selection of phytoplankton groups, such as Microcystis aeruginosa. We begin with a data compilation and analysis of environmental data from Lake Erie. This data analysis of nutrient concentrations, pigment concentrations, and zooplankton biomasses helps us understand and interpret what is happening in the environment throughout the year. Thus, allowing us to build a mathematical model to test our hypothesis. Our mathematical model asses …

Neutrophil Subtype Differentiation In Campylobacter Jejuni Infection And Its Impact On T Cells And Colonic Epithelial Cells, Carolina Dolislager

Masters Theses

The discovery of neutrophil subtypes has expanded what is known about neutrophil functions, yet there is still much to learn about the role of these subtypes during bacterial infection. We investigated whether Campylobacter jejuniinduced differentiation of human neutrophils into the hypersegmented, CD16^hi/CD62L^lo[CD16hi/CD62Llo] subtype. In addition, we investigated whether C. jejuni-dependent differentiation of this neutrophil subtype induced cancer promoting activities ofhuman T cells and colonocytes, whichwere observed in other studies of hypersegmented, CD16^hi/CD62L^lo[CD16hi/CD62Llo] neutrophils. We found that C. jejunicauses a significant shift in human neutrophil populations to the hypersegmented, CD16 …

Investigating The Mechanisms And Specificity Of Bacterial Virulence In An Entomopathogenic Symbiosis, Elizabeth Ransone

Masters Theses

Microbial symbionts contribute to the health of their host in both positive and negative ways. In the Steinernema nematode symbiosis, Xenorhabdus symbionts traditionally mediate insect virulence by producing toxins and other virulence proteins against the insect prey that they both need for sustenance. In this work, I took a bidirectional approach to the question: what is the larger role of Xenorhabdus in virulence against insect prey? 1) I investigated a novel protein family, typified by the Xenorhabdus bovienii polymorphic protein (Xbpp) with strain-level protein diversity. I found that Xbpp contributes to X. bovienii virulence in a Manduca sexta tobacco hornworm …

Effects Of Traditional And Microbially-Focused Restoration Techniques On Soil Communities In Tallgrass Prairies, Zachary J. Whitacre

Masters Theses

Tallgrass prairies have virtually disappeared in many parts of their former range due to the conversion of this ecosystem to farmland. In more recent years there have been efforts to restore these prairies on reclaimed agricultural land. However, these restored prairies do not resemble their remnant counterparts in many ways, such as in soil microbial community composition and metrics related to carbon storage. In Chapter 1, I show that bacterial communities in a restored prairie and an adjacent remnant prairie in southwest Michigan differ in their immediate and longer-term responses to prescribed fire, a commonly used prairie restoration and maintenance …

Investigating Microbial Genes Involved In Plant Colonization And The Effects On Plant Microbiome Assembly, David Grant

Masters Theses

The use of chemical fertilizers and pesticides has had negative impacts on ecological systems and alternatives will be needed to both enhance agricultural production and remediate waste that has accumulated via fertilizer use. A promising alternative to tackle both problems utilizes beneficial organisms in microbial communities associated with plants, which are known as bioinoculants. However, the benefits of bioinoculants are inconsistent in field application and require more research in order to harness them in ways to make them a suitable replacement for chemical fertilizers. Here, I investigate characteristics required to enhance bioinoculant efficiency, including mechanisms required to increase microbial colonization …

Phytophthora Capsici In Tennessee: Fungicide Resistance, Population Genetics And Cultural Control, Timothy Brent Siegenthaler

Masters Theses

Phytophthora capsici, a plant pathogenic oomycete, is the causal agent of the vegetable disease Phytophthora blight of pepper and cucurbits. Since the identification of P. capsici in 1922, a significant amount of research has been conducted to understand its biology and disease management. Despite this, little research had been conducted on this species in the state of Tennessee. Three studies were done from 2018 to 2020, focusing on fungicide resistance, population genetics, and testing management strategies in the field. In 2018 and 2019 a total of 248 isolate of P. capsici were collected from five counties in Tennessee. These isolates …

Carbon Metabolism In Cave Subaerial Biofilms, Victoria E. Frazier

Masters Theses

Subaerial biofilms (SABs) grow at the interface between the atmosphere and rock surfaces in terrestrial and subterranean environments around the world. Multi-colored SABs colonizing relatively dry and nutrient-limited cave surfaces are known to contain microbes putatively involved in chemolithoautotrophic processes using inorganic carbon like carbon dioxide (CO₂) or methane (CH₄). However, the importance of CO₂ and CH₄ to SAB biomass production has not been quantified, the environmental conditions influencing biomass production and diversity have not been thoroughly evaluated, and stable carbon and nitrogen isotope compositions have yet to be determined from epigenic cave SABs. …

Evaluation Of The Symbiotic Relation Between Endophyte And Poplar Trees Exposed To Landfill Leachate, Catalina Vega Hurtado

Masters Theses

“The contamination of soil and groundwater from leachate leakage from landfill has turned, nowadays, into a global public issue. One of the main concerns about this pollutant is the potential threat to human and ecosystem health. The current research studied endophyte bacteria in association with poplar trees (Populus sp.), as a method of bioremediation of landfill leachates. The objective of the project was to identify treatment strategies that may improve plant performance (survival rates, plant fitness, and degradation efficacy) with the purpose of being implemented in phytoremediation plots, aimed to intercept and treat landfill leachate, before the contamination of watershed. …

Detection Of Beta-Lactamase Variants In Municipal Wastewater And Fresh Water, Sunil Pandey

Masters Theses

The occurrence and spread of antibiotic-resistant genes (ARGs) are pressing public health problems worldwide. A key factor contributing to the spread of ARGs is lateral gene transfer. Wastewater treatment plants (WWTPs) are measured hot spots of microbial diversity and resistance because they receive polluted wastewater from diverse sources and contain a variety of different environments with dense bacterial loads. Due to the overuse of antibiotics the genetic capacities of microbes have profited. This helps every source of resistance gene and every means of horizontal gene transmission to develop the multiple mechanism of resistance to each antibiotic used clinically, agriculturally, or …

Xylan Metabolism By Caulobacter Crescentus, Viet Bui

Masters Theses

Bacteria present unique opportunities to explore the molecular mechanisms of nutrient acquisition processes at single cell level under various experimental conditions. Caulobacter crescentus is a gram-negative oligotrophic environmental bacterium with adaptive physiological responses, such as slow growth or complete arrest of cell cycle, presence of sessile and motile progenies with the sessile cells growing stalk to enhance nutrient uptake for growth in low-nutrient conditions. Details of plant polysaccharide-derived carbon compound, such as cellobiose, maltose, and xylose utilization by C. crescentus can be found but molecular details or mechanisms of polysaccharide utilization, such as xylan, has not been reported. Database analyses …

Impacts Of Plant-Microbe Interactions On Seedling Performance In A Riparian Forest Invaded By Lonicera Maackii, Taylor E. K. Strehl

Masters Theses

Soil microbes have profound impacts on plant growth and survival and can either promote or inhibit plant dominance. Exotic plants are often strongly invasive because they have escaped their natural enemies, potentially including antagonistic soil microbes. I examined how the invasive shrub Lonicera maackii and a common native tree, Acer negundo, responded to soil microbial communities to determine the role of soil microbes in regulating invasion success. This was done by growing both species with microbes from invaded (L. maackii) and uninvaded (A. negundo) soils collected from three locations within a riparian forest. Seedlings were …

Evaluation Of Intra-Species Diversity Of Oxalobacter Formigenes Strains Using Pulsed-Field Gel Electrophoresis (Pfge) And Multiplex Pcr, Nivedita Pareek

Masters Theses

Oxalobacter formigenes is a beneficial, strict anaerobic gut bacterium that plays an important role in the prevention of kidney stone disease with a unique characteristic of using only oxalate as a carbon and energy source. To date, twenty-one strains of O. formigenes have been isolated which are further divided into two groups based on differences in the patterns of cell membrane lipids, cellular proteins, and nucleic acid fragments. The objective of the study was to evaluate intra-species diversity of O. formigenes strains using pulsed-field gel electrophoresis (PFGE) and multiplex PCR.

Nine pure cultures of O. formigenes strains (5 strains group …

Characterization Of Pinitol Catabolism In Sinorhizobium Meliloti And Its Role In Nodule Occupancy, Angela Irene Kennedy-Mendez

Masters Theses

Sinorhizobium meliloti, which is the nitrogen fixing symbiont of Medicago sativa (alfalfa), was used to test the hypothesis that D-chiro-inositol is an intermediate of pinitol catabolism and that pinitol catabolism plays a role in S. melilot s ability to compete for nodule occupancy. An analytical method, involving gas chromatography and mass spectrometry (GCMS), was developed to detect and separate pinitol and D-chiro-inositol. The S. meliloti wild type, and three isogenic mutant strains (idhA, mocD, and mocE) were grown in minimal medium with pinitol and pinitol plus glycerol. The S. meliloti wild type can utilize pinitol as a sole carbon source, …

Biotransformation Of Oxo-Bile Acids Derivatives By Human Gut Bacteria, Laina Sallam

Masters Theses

Bile acids are one group of steroids that can be metabolically transformed by human gut anaerobes. One of these transformations is the conversion of primary bile acids to secondary bile acids by 7α-dehydroxylating gut bacteria such as Clostridium scindens, Clostridium hylemonae, and Clostridium hiranonis. These anaerobes metabolize bile acid derivatives via 3α- and 7α-hydroxysteroid dehydrogenases (HSDH). Studies to date have not reported if these organisms are capable of converting 12-oxolithocholic acid (12-oxoLCA) to deoxycholic acid (DCA). The emphasis of this study was to determine the ability of C. scindens ATCC 35704, C. hiranonis DSM 13275, and C. …

Resolution Of The Nutritional Requirements And Metabolic Profile Of Clostridium Scindens Atcc 35704, A Major Bile Acid-Dehydroxylating Anaerobe In The Human Gut, Rachana Shrestha

Masters Theses

Bile acids (cholate and chenodeoxycholate) are synthesized from cholesterol in the human liver, and secreted in small intestine for food digestion. However, a portion of these primary bile acids is converted in the colon to toxic secondary bile acids, deoxycholate and lithocholate. Secondary bile acid formation is the result of 7α-dehydroxylating anaerobes, and one of the key players in this conversion is Clostridium scindens. Interestingly, little is known about the basic physiology and nutrition of C. scindens. Therefore, the goal of this research was to understand the nutritional requirement, and determine the 7α-dehydroxylation activity and end products from …

Distiphallus Morphology And Its Role In Copulation Dynamics In Anastrepha Suspensa (Loew), Taylor J. Inboden

Masters Theses

Anastrepha suspensa (Diptera; Tephritidae) is an agricultural pest species

causing severe economic damage and is controlled, in part, by applying knowledge

of this species' reproduction (e.g., disrupting fertile copulations by SIT). During

copulation, males transfer sperm as well as protein rich fluids through an aedeagus

and distiphallus, which females then store in three spermathecae and one ventral

receptacle. Within the female reproductive tract, the ventral receptacle and the

three spermathecae are strategically separated from each other. I hypothesized

males' ability to direct sperm transfer within the female reproductive tract is

through the structures found in the distiphallus. Utilizing scanning electron …

Heat Inactivation Kinetics Of Tulane Virus And Aichi Virus, Sukriti Ailavadi

Masters Theses

Human noroviruses (HNoVs) and Aichi virus (AiV) causes significant number of gastrointestinal diseases worldwide. Tulane virus (TV), a cultivable HNoV surrogate, is used to determine control measures against HNoV. The objectives of this study were to determine the heat inactivation kinetics of TV and AiV in cell-culture media and TV in spinach using the first-order and Weibull models. TV and AiV in cell-culture media at ~7 log PFU/ml in 2-ml glass vials were heated at 50-58°C [degree Celsius] up to 10 min in a circulating water-bath. Surviving infectious viruses were enumerated by standard plaque assays using confluent host cells in …

A Bug’S Life: Integration Of Anaerobic Digestion And Bioelectrochemical Systems For Enhanced Energy Recovery From Wastewater Solids And Other Waste Substrates, Jeff Ryan Beegle

Masters Theses

Organic waste streams, like domestic wastewater and municipal solid waste, have the potential to be used as feedstocks for biotechnology processes to produce high value products and energy. This thesis investigated the technological, economical, and environmental potential for integrated anaerobic digestion (AD) and bioelectrochemical system (BES) platforms as they were theoretically and physically evaluated for energy recovery from domestic wastewater. The first chapter of this thesis compared the theoretical energy efficiencies of converting waste directly into electricity, using AD and BES alone and in various combinations. This chapter reviewed the experimentally demonstrated energy efficiencies reported in the literature with comparisons …

Investigating The Sources And Dynamics Of Escherichia Coli In A Missouri Ozarks Watershed, Kaleb Bassett

Masters Theses

"Escherichia coli, an intestinal bacterium, can serve as an indication of the presence of pathogenic microorganisms in water systems used by humans for recreation, agriculture, or drinking water. Many aquatic systems in the United States exceed the E. coli standard, set by the Environmental Protection Agency, for safe drinking water and recreational use. During 2016, a water sampling program was established in the Mill Creek watershed, a rural watershed located near the city of Newburg in Phelps County, Missouri. Water samples were collected before, during, and after storms throughout the year to examine the relationship between E. coli …

Detection Of Antibiotic Resistance Loci In Wastewater And Fresh Water Samples, Mohammed Hamed Almalki

Masters Theses

Proper treatment of municipal wastewater is important not only for prevention of eutrophication but also for public health concerns. One consideration for wastewater treatment is the presence of organisms carrying antibiotic resistance genes. If these organisms survive the wastewater treatment process and are released into the streams, they can pose significant risks to public health. In addition, their presence also raises concerns for lateral gene transfer events at the wastewater plant. The spread of antibiotic loci has a major impact in public health and clinical therapy because resistant organisms render conventional treatments of important illnesses difficult. Beta-lactam drugs are known …

Media Optimization, Scale-Up And Repeated Fed-Batch Operations For The Production Of 1,3-Propanediol From Glycerol By Halanaerobium Hydrogeniformans, Shivani Kalia

Masters Theses

"The development of renewable energy sources, such as biofuels, is of great interest in today's world due to depletion of fossil fuels and concerns about climate change. The production of the main by-product, crude glycerol, in biodiesel production presents an opportunity for the production of industrially relevant commodities. Crude glycerol in biodiesel waste is highly impure and possesses high salt concentrations and alkalinity, making it infeasible for direct industrial utilization. Moreover, current glycerol purification methods are highly cost-intensive, necessitating a search for cost-effective approaches that are feasible to employ. Genome data analysis of Halanaerobium hydrogeniformans, revealed the metabolic capability …

Switchgrass Extractives Have Potential As A Value-Added Antimicrobial Against Plant Pathogens And Foodborne Pathogens, Alexander Ian Bruce

Masters Theses

Panicum virgatum (switchgrass), a perennial grass native to North America, is a leading biomass feedstock candidate for the manufacture of cellulosic ethanol. Switchgrass is considered a viable option for biofuel production due to its cheap production cost and ability to grow on marginal land. Biofuel derived from switchgrass has been shown to be very energy efficient, producing 540% more renewable energy versus nonrenewable energy expended. Switchgrass-derived biofuel is also estimated to have greenhouse gas emissions that are 94% lower than emissions from gasoline (Schmer et al 2008). Biofuels are created through biochemical processes that utilize various enzymes and microorganisms for …

Chemokines And Peptides That Promote And Inhibit Cmv Entry, Elisabeth Anne Pitt

Masters Theses

Human cytomegalovirus (HCMV) causes morbidity and mortality in congenitally infected newborns, transplant recipients, and AIDS patients. Currently, there is no approved CMV vaccine to address these issues. In an effort to develop an alternative treatment to CMV we tested our hypothesis that heparan sulfate binding D-peptides would be effective against multiple HCMV strains in vitro and it would be effective in vivo against murine CMV (MCMV) (Chapter 1). We show that the D-peptide is able to reduce CMV infection in vitro and in vivo. Another approach to combating CMV infections is to neutralize pathogenic factors that contribute to CMV …

Improving Aedes Mosquito Surveillance And La Crosse Virus Screening In Eastern Tennessee, Cassandra Urquhart

Masters Theses

La Crosse virus (LACV), transmitted by infected Aedes triseriatus, Ae. albopictus, and Ae. japonicus mosquitoes is the leading cause of pediatric arboviral encephalitis. Severe cases of LAC encephalitis occur in individuals 16-years-old or younger and may cause permanent neurological damage or fatality. No vaccines exist making mosquito control and disease prevention crucial to public health. Effective screening and surveillance practices are key components to these goals. While a number of standard mosquito surveillance methods exist, continuous testing and improved understanding of vector biology to determine the best ways to implement these methods is important. Additionally, the current standard …

Microbial Extracellular Enzymes In Marine Sediments: Methods Development And Potential Activities In The Baltic Sea Deep Biosphere, Jenna Marie Schmidt

Masters Theses

The deep biosphere is defined as the subsurface ecosystem in which little energy is available to microorganisms and microorganisms can live for thousands of years. Heterotrophic microbes survive in the deep biosphere even though organic matter is limited and highly recalcitrant in nature. Measuring microbial extracellular enzyme activity provides a potential means to evaluate the rate at which microorganisms are performing carbon remineralization in the energy limited sediment beneath the seafloor. Extracellular enzymes breakdown organic compounds so that the nutrients can move inside the cell and be used for energy. This study explored the role extracellular enzymes play in the …