Life Sciences Commons^™

The Bacteria Who Lived: Uncovering And Mitigating The Persistence Of Pathogens In Low-Moisture Food Processing, Kavita Shripati Patil

Graduate Theses and Dissertations

Low-moisture food (LMF) processing environments pose a persistent food safety risk due to Salmonella survival and harborage on surfaces. This work investigates persistent bacterial populations (PBPs) in LMF production environments, focusing on identifying a suitable surrogate and evaluating sanitation strategies. Three potential surrogates, Escherichia coli MP 26, Enterococcus faecium, and Pediococcus acidilactici, were compared to Salmonella PBPs formed in nonfat dry milk (NFDM) on stainless steel coupons stored at 25°C under 30% or 70% relative humidity (RH) using two different inoculation methods. E. faecium showed survival patterns most similar to Salmonella, with no significant differences in log reductions (p > 0.05), …

Effects Of Flavonoids On Reducing Colon Cancer Risk Via Macrophage Polarization, Gracien Jules

Graduate Theses and Dissertations

Colorectal cancer is one of the most fatal diseases in the United States. Chronic tissue inflammation can cause cell proliferation, which leads to tumor formation and cancer development. Macrophages are responsible for maintaining tissue homeostasis and for inflammatory responses. M1 macrophages exhibit proinflammatory responses while M2 macrophages exhibit anti-inflammatory responses. Imbalance between M1 and M2 macrophages is closely related to inflammation-associated disease development. The anti-inflammatory effects of apiaceous vegetable constituents, specifically flavonoids, have been studied for their preventative effects towards reducing disease risk. However, sufficient evidence is lacking on the mechanisms by which flavonoids impact M1/M2 macrophage polarization. RAW 264.7 …

Improved Autofluorescence Lifetime Decay Analysis For Identification Of Cellular Autofluorescence Biomarkers For Label-Free, Single-Cell Assessment Of Mitochondrial Membrane Potential, Olivia Isabel Kolenc

Graduate Theses and Dissertations

Optical imaging of metabolism using the autofluorescence of the metabolic cofactors NADH, NADPH, and FAD has a wide range of sensitivities and the capability to collect a great deal of metabolic information. Multiphoton microscopy (MPM) is a non-invasive, label-free optical imaging technique capable of performing fluorescence lifetime imaging (FLIM) using time correlated single photon counting (TCSPC). However, autofluorescence FLIM presents a challenge in collecting sufficient photons to provide adequate signal to noise ratios (SNR) for analysis. Additionally, the specificity of autofluorescence biomarkers of metabolism has not been well-defined. Contextualizing these autofluorescence measures using established functional biomarkers can improve interpretability of …

Host-Virus Interaction Dynamics Using Sulfolobus Spindle-Shaped Virus And Host Sulfolobales System, Yeasin Ahmed

Graduate Theses and Dissertations

The Sulfolobus Spindle-shaped virus (SSV) is among the most studied archaeal viruses, particularly in extreme environments. This virus predominantly infects multiple Crenarchaea from the Sulfolobaceae family. These hosts thrive in extreme environmental conditions, such as sulfuric hot springs, with a pH of 2 to 4 and a temperature of 76-80˚C. Sulfolobales exhibit a wide geographical distribution across volcanic hot springs. The Sulfolobus Spindle-shaped Virus (SSV), encompassing strains such as SSV1 and SSV8, employs a non-lytic replication strategy in hosts belonging to the order Sulfolobales. The SSV-Sulfolobales system can be cultured in liquid and gellan gum solid media. A comprehensive study …

Examining The Use Of Two-Dimensional Video Capture And A Pressure Sensing Walkway For Collection Of Obstacle Crossing Measures, Ashlyn M. Jendro

Graduate Theses and Dissertations

Obstacle crossing research is crucial for providing insights into how and why people trip and fall. However, a growing body of literature has proposed that laboratory-based studies may not directly translate into real-world settings due to the complex nature beyond the sterile lab. Unfortunately, the absence of real-world obstacle crossing literature is likely due to a lack of available validated methods for collection of data outside the laboratory. This dissertation explored two potential methodologies (i.e., 2D motion capture and a pressure sensing walkway) that are more portable and cost-effective for collecting real-world obstacle crossing measures. It is hypothesized that 2D …

Freezing And Shipping Optimization To Increase Quality And Profitability Of Meat E-Commerce, Paul Olaoluwaniyi Dahunsi

Graduate Theses and Dissertations

Freezing remains one of the most reliable methods for preserving meat quality and extending shelf life. However, quality deterioration can still occur due to structural and biochemical changes activated during freezing, thawing, and distribution. Since the COVID-19 pandemic, consumers’ preference for bulk purchasing and online meat shopping has increased, raising questions about the best strategies to balance both quality maintenance and profitability. This thesis aimed to evaluate two key stages where frozen beef is most vulnerable to quality degradation: consumer-level freezing and post-purchase shipping. The objectives were (1) to determine the effects of product size and subsequent consumer freezing practices …

A Multicomponent Microneedle Patch For The Delivery Of Meloxicam For Veterinary Applications, Katherine Alejandra Miranda Munoz

Graduate Theses and Dissertations

Veterinary medicine requires innovative drug delivery strategies to enhance therapeutic efficacy while minimizing stress and handling. This dissertation explores the development and application of biodegradable microneedle patches for the transdermal delivery of meloxicam in livestock, offering a minimally invasive alternative to traditional administration methods. The research investigates the fabrication and characterization of microneedles using polyvinyl alcohol, collagen, and chitosan blends, demonstrating their mechanical strength, biocompatibility, and ability to facilitate sustained drug release. In vitro and in vivo evaluations confirm effective skin penetration, dissolution, and localized drug delivery. Pharmacokinetic studies highlight anatomical site-dependent variations in drug absorption, emphasizing the need for …

Small Angle X-Ray Scattering Studies Of Collagenase H Mutant, Colh-E416q, Madelyn Millsap

Graduate Theses and Dissertations

Collagenase H (ColH) from Hathewaya histolytica plays a central role in collagen degradation through endopeptidase and carboxytripeptidase reactions. To better understand how its domain architecture supports these functions, we examined the solution structure of a catalytically inactive mutant, ColH-E416Q, using small-angle X-ray scattering (SAXS). The E416Q mutant is catalytically inactive because the glutamate residue at position 416, which normally functions as a general acid/base during catalysis, is replaced by glutamine—an amide that cannot donate or accept protons effectively, thus disabling the proton transfer steps essential for peptide bond hydrolysis. SAXS results indicate that the E416Q substitution leaves overall domain architecture …

Effect Of Dietary Tryptophan Supplementation And Heat Stress On Pasture Broiler Welfare And Performance, Jaelen Matthew Cherry

Graduate Theses and Dissertations

Pasture-raised broiler chickens face temperature extremes that can threaten welfare. In the study, we evaluated whether a 0.26 % tryptophan-supplemented diet (T) improved heat stress (HS) resilience in Ross-708 broilers raised on pasture. At D14, birds began the T or remained on the control diet (C) and were moved outdoors. On D20 and 41, half of each group underwent six-hour HS; the remainder stayed under thermoneutral (TN) conditions. Weekly body weight, feed intake on D20 and D41 were recorded, and fear was measured using the Tonic Immobility (TI) test. Neither diet nor HS affected body weight. However, tryptophan supplementation resulted …

Modeling U.S. Corn Production Archetypes In The Agricultural Policy/Environmental Extender Model To Generate Life Cycle Assessment Inventory Data, Brandon Taylor

Graduate Theses and Dissertations

Corn (Zea mays) is an important crop grown across the US for many uses such as grain for animal feed, bio-ethanol production, food products, and industrial products. Corn is produced in almost every state in the US, but most corn production is concentrated in the Corn Belt Region including Iowa, Illinois, Ohio, Indiana, Minnesota, and Nebraska. Although technologies and production practices are improving corn production efficiency primarily through increased yields (improved land use), corn production at this scale greatly impacts the environment through emissions from fertilizer and pesticide runoff and leaching, soil degradation due to improper field practices, as well …

An Analysis Of Cellular And Tissue Function Of Lipin In Drosophila Melanogaster, Judah Christian Scott

Graduate Theses and Dissertations

Regulation of energy expenditure and energy storage is a key characteristic of life. Numerous enzymes play a crucial role in regulating energy metabolism. Lipins are a highly conserved family of proteins that function in both lipid synthesis and gene regulation. In the glycerol-3 phosphate pathway, lipins act as a phosphatidate phosphatase (PAP) producing diacylglycerol. In gene regulation, lipins act as transcriptional co-regulators of metabolic genes. The enzymatic PAP activity occurs in the cytoplasm; however, for lipins to function as gene regulators, they must translocate into the nucleus. Nuclear translocation is facilitated by the nuclear localization signal (NLS) within the protein. …

Fractured Inheritance: Quantifying The Economic Impact Of Heir’S Property On Arkansas Farmers, Makenzie Mcjunkins

Graduate Theses and Dissertations

Heir’s property arises when the original owner still holds the title despite their passing, and ownership is distributed among their heirs. This was driven by barriers to retaining land ownership and access to legal support in predominantly African American populations in the early 20th century. This approach allowed land to remain in the original owner's name while granting continued ownership to future generations without formal paperwork. Additionally, allowing limited land access, land management, and disparities in capital access compared to property with direct ownership rights. This analysis examines how modern heir’s property impacts agricultural returns. This study develops a conceptual …

Leveraging Natural Variation In Yeast To Understand Susceptibility Differences In Parkinson’S Disease, Julio Andres Molina Pineda

Graduate Theses and Dissertations

Parkinson’s Disease (PD) is a neurodegenerative disorder that causes countless suffering around the world. Both forms, familial and sporadic, have been associated with the misfolding and cytotoxicity of α-synuclein, an otherwise non-pathogenic protein suspected to have various roles in the normal maintenance of the central nervous system. Model organisms have emerged as great vessels to uncover the cellular and molecular mechanisms that shape α-syn biology, and great strides have been made to understand it. Yet, it is still unclear why some individuals are affected by α-syn toxicity, while others not so much. Since it’s extremely complicated to study and probe …

Bang!: Real-Time Measurements And Transcriptomics Of Metabolic Reprogramming In Activated Macrophages At Fever Temperature, Kenneth Howard Taylor

Graduate Theses and Dissertations

We investigated the real-time metabolic rates of activated macrophage cell lines derived from mouse, chicken and rainbow trout. Each species showed a different kinetic signature with metabolic rates accelerating under fever conditions specific to each organism. Upon activation mouse macrophages increased their rate of glycolysis early and then a later reprogramming phase occurred with a dramatic decrease in oxidative phosphorylation (OXPHOS) accompanied by a reciprocal second increase in glycolytic rates. Chicken macrophages showed an initial increase in both glycolytic and OXPHOS rates. The late drop OXPHOS rates also occurred in chicken however there was no reprogramming that occurred as glycolytic …

The Evolving Changes In The Regionalization Of Export Bans On U.S. Poultry Trade From The 2015 And 2022 Highly Pathogenic Avian Influenza Events, Kylie A. Roesler

Graduate Theses and Dissertations

As food security becomes a growing concern worldwide in a trading system dominated by globalization, the safeguarding of a bio-secure food system is at risk. One of the greatest risks to this stability of the system is, highly pathogenic avian influenza or HPAI which is growing in frequency and impact. Therefore, the global response to disease events is evolving into a newfound understanding of disease prevalence across the animal protein industries. This study will analyze the 2022 HPAI event in the United States regarding the regionalization of restrictions imposed by trading partners accounting for trade agreements executed. The examination of …

Physiological And Molecular Responses Of Diverse Rice Genotypes Under Drought Stress, Huda Mohmmed Alshaya

Graduate Theses and Dissertations

Climate change-induced drought stress is a significant constraint on global rice (Oryza sativa L.) production, threatening food security. This study evaluated the drought resilience of 15 diverse rice genotypes from the USDA mini-core collection under field, greenhouse, and osmotic stress conditions. Field trials assessed reproductive-stage drought tolerance based on panicle length (PL), number of spikelets per panicle (NSP), and spikelet sterility (SS). Greenhouse experiments examined moisture retention at the vegetative stage. Significant genotypic variation was observed, with genotypes 310724, 310779, 311181, 311603, 311793, and Vandana exhibiting drought tolerance through stable PL and SS. Additionally, genotypes 310100, 310428, 311255, N22, …

Identifying Microbial Complexities And Control Strategies At Pre-Harvest Poultry Production, Tolulope Tiwa Ogundipe

Graduate Theses and Dissertations

While significant progress has been made in post-harvest control of Salmonella in the poultry industry, the development of effective pre-harvest intervention strategies remains critical for reducing foodborne pathogens. Environmental reservoirs such as poultry litter and drinking water systems (DWS) are potential harborage sites for Salmonella and other microbial communities. Understanding the microbiota of these environments, including biofilms within water lines, is essential to identifying factors contributing to Salmonella colonization and improving pre-harvest control approaches. This study aimed to evaluate the incidence and quantity of Salmonella in poultry litter and water lines, characterize the microbial populations in these environments, and assess …

Flexible Microelectrode-Based Impedance Immunosensor For Rapid Detection Of E. Coli O157:H7, Sonatan Kumar Biswas

Graduate Theses and Dissertations

Abstract Food contamination poses a significant threat to public health, the economy, and human health worldwide, occurring at any stage of the food supply chain, from farm to fork. Escherichia coli 0157:H7, recognized as one of the principal causes of foodborne illness, poses a considerable risk to food safety. The primary objective of this investigation is to devise a flexible microelectrode-based immunosensor capable of swiftly identifying E. coli O157:H7 cells without the need for incubation in a pure culture environment. In the development of the biosensor, the gold electrode (composed of 50% Au) underwent an initial coating process involving 2-aminoethanethiol/cysteamine, …

Evaluation Of Fluridone In Rice, Maria Carolina De Carvalho Rocha Souza

Graduate Theses and Dissertations

The increasing pressure of Palmer amaranth [Amaranthus palmeri (S.) Watson] in rice (Oryza sativa L.) fields demands new chemical control options to manage this weed. The recent labeling of fluridone on this crop from the three-leaf rice stage offers an additional residual herbicide for battling Palmer amaranth; however, research is needed to evaluate its effectiveness and rice tolerance. Field experiments were conducted to evaluate Palmer amaranth control and rice tolerance to fluridone across different locations in Arkansas in 2022, 2023, and 2024. Preemergence (PRE) applications of fluridone at 168 g ai ha^⁻1; (1× label rate) and 336 …

Crispr-Cas9 Integration Of Salmon Elovl2 In Zebrafish Enhances Lc-Pufa Biosynthesis And Growth Across Diets, Waleed Sami J. Al-Bachry

Graduate Theses and Dissertations

Fish are a rich source of EPA and DHA, which are well-known long-chain polyunsaturated fatty acids (LC-PUFAs). The sustainable production of these essential fatty acids poses significant challenges, mainly due to our dependence on marine fish and certain nuts. CRISPR-Cas system was utilized to insert the elongation of long-chain fatty acids-like2 (Elovl2) gene from Salmo salar into Danio rerio. Elovl2 was introduced at 10-15-minute post-fertilization, and successful integration confirmed by PCR genotyping, sequencing and expression of EGFP. Approximately 67% of injected embryos successfully exhibited EGFP and sequence results verified the gene integration of Salmo salar Elovl2 at the first start …

Variation In Stress Response Regulation Across Natural Isolates Of Saccharomyces Cerevisiae, Crystal Christine Crook

Graduate Theses and Dissertations

The stress response of Saccharomyces cerevisiae is a valuable area of study for understanding cellular adaptation mechanisms that govern survival in fluctuating environments. This dissertation investigates stress response regulation in yeast through the roles of Hog1 mitogen-activated protein kinase (MAPK) and the post-transcriptional regulator Mkt1, a key post-transcriptional regulator, in diverse wild yeast isolates. Hog1 is traditionally known for its central role in osmotic stress regulation in the high-osmolarity glycerol (HOG) pathway. This study expands the functional scope of Hog1 to include oxidative and ethanol-induced stress responses.

In parallel, we investigate post-transcriptional regulation of stress responses by the Mkt1 interactome, …

The Efficacy Of Foam-Based Hand Sanitizers For The Control Of Enveloped And Non-Enveloped Virus Transmission, Francis Torko

Graduate Theses and Dissertations

Infectious disease transmission due to viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza virus, human noroviruses (HuNoV), and hepatitis A, can occur via person-to-person contact or contaminated surfaces. Effective hand hygiene, including hand washing and use of hand sanitizers, is considered a critical tool for the control of infectious disease transmission, as recommended by the United States Centers for Disease Control and Prevention and the World Health Organization. However, while research on hand washing efficacy is well-documented, research on hand sanitizer efficacy, particularly for foam-based products, remains limited. This research addressed critical gaps in the area of …

Fish Cultivation In Fallow Season Rice Fields: Effects On Landscape Methane Emissions, Samuel Carroll

Graduate Theses and Dissertations

Co-cultivation of aquatic animals and rice in the same field is a fairly common practice in various parts of the world, with a number of well-established agro-ecological benefits, such as decreasing the need for chemical pesticides and fertilizers, increasing soil organic matter, and reducing the land area needed for agricultural production. One area of environmental concern in rice production is greenhouse gas emissions. Rice production contributes about 10% of global anthropogenic methane (CH₄) emissions. Currently around 27.5% of Arkansas rice fields are flooded in the winter, which can increase CH₄ emissions in the fallow season by 45% …

Implications Of Acetylation And Phosphorylation On Metabolic Enzymes, Nour Fatema

Graduate Theses and Dissertations

All living things depend on glycolysis and the TCA cycle for energy production and metabolic control. Post-translational modifications (PTMs) such as acetylation and phosphorylation, which can change enzyme activity, substrate binding, and overall metabolic balance, tightly regulate these pathways. Diseases like cancer and metabolic problems are associated with disruptions in these alterations.

Serine phosphorylation and lysine acetylation are two of the many PTMs that are evolutionarily conserved processes that alter protein function. Previously thought to be a static histone alteration, acetylation is now understood to be a dynamic regulator of metabolic enzymes that modifies contacts, charge, and conformation. In response …

Developing Custom Fertilizer Strategies Recirculating Hydroponic Systems, Joshua Bryan Tebow

Graduate Theses and Dissertations

Hydroponic systems recirculate nutrient solution to reduce the amount of water used in leafy green production. However, the rootzone of the nutrient solution is complex and influenced by interacting factors such as plant uptake demand, irrigation water quality, supplied fertilizer salts and nutrient concentrations, environmental conditions, and injection of mineral acids/bases to control solution pH. A common strategy for managing nutrients in commercial production is to select a hydroponic solution formulation (i.e. recipe) to supply and maintain a target pH and electrical conductivity (EC) in the recirculating solution over time by automatic injection of mineral acids/bases and concentrated fertilizer stock …

Fixed-Time Artificial Insemination Protocols Using Pre-Synchronization In Suckled Beef Cows, Wyatt Eugene Weber

Graduate Theses and Dissertations

Adoption of artificial insemination by beef producers has been limited within the United States. Estrous synchronization (ES) for fixed-time artificial insemination (FTAI) has been one of the most effective ways to implement artificial insemination into beef production systems, but its efficiency has primarily been restrained by the dependency on the effectiveness of the initial gonadotropin releasing hormone (GnRH) injection in many FTAI protocols. The hypotheses of these studies were to determine practical methods of pre-synchronization to improve current FTAI protocols, ultimately increasing beef herd reproductive performance. The objective was to evaluate the use of prostaglandin F2α (PGF) and progesterone (P4) …

Livestock Risk Protection Basis Risk For Feeder Cattle, Bryce Anderson

Graduate Theses and Dissertations

Recent government subsidies make livestock risk protection (LRP) insurance an affordable price risk management tool for many U.S. cattle producers. LRP insurance triggers a loss when the Chicago Mercantile Exchange (CME) Feeder Cattle Index falls below the selected coverage price. The CME Feeder Cattle Index is a 7-day weighted average of feeder cattle prices in 12 states. This paper determines if LRP policy holders who produce feeder cattle in states whose feeder cattle prices are not included in the CME Feeder Cattle Index are exposed to excess basis risk. To do this, we use a hedonic regression model to determine …

Evolutionarily Conserved Functions Of The Gene Frazzled In Midline Axon Guidance In Drosophila Melanogaster And Tribolium Castaneum., Piyasi Ghosh

Graduate Theses and Dissertations

Axon guidance in bilaterians is often controlled by various signaling pathways in the nervous system, which determine the fate of the axons if they cross the midline or not. One such pathway involved is the ligand-receptor pair Netrin (Net) and Frazzled (Fra), which is also known as the attractive pathway that promotes midline crossing axons in insects and other bilaterians. Orthologs of the pathway ligand Netrins and their receptors Frazzled [Fra] in insects and Deleted in Colorectal cancer [DCC] in vertebrates are widely conserved in bilaterians. How well these regulatory roles of the protein are conserved is poorly understood. In …

Bacterial Chondronecrosis With Osteomyelitis In Broiler Chickens: Experimental Lameness And Additive Probiotic Treatments, Amanda Anthney

Graduate Theses and Dissertations

With the global population already surpassing 8.2 billion and expected to reach 9.7 billion by 2050, the poultry industry has seen a surge in demand due to its unmatched efficiency and affordability for consumers across the globe. Selective breeding and quality nutrition developments since the industry's commercialization have allowed producers to grow broilers up to 7 pounds by market age. While this extraordinarily efficient process has allowed quality poultry products to be available worldwide, the modern-day broiler has developed a multitude of musculoskeletal issues. Due to the lack of integral skeletal development to match the rapid production of muscle tissue, …

Investigating Evolution Through The Lens Of Ai-Driven Protein Exploration And Phylogenetic Modeling, Mataya Duncan

Graduate Theses and Dissertations

Recent advances in computational biology, artificial intelligence, and sequencing technologies have enabled new perspectives for addressing longstanding questions in evolutionary biology. Increased computational power has made large-scale simulations feasible for investigating diverse aspects of evolutionary and phylogenetic modeling. Similarly, deep learning algorithms now allow for the prediction of reasonably accurate tertiary protein structures, unlocking the potential for investigating diversity and evolution of protein structure across a broad range of organisms. This thesis presents two studies that target different aspects of evolutionary inference from unique perspectives. Yet, the share an overarching goal of presenting new perspectives on the evolutionary basis of …