Life Sciences Commons^™

Evaluation Of Soil Steaming, Cover Crops, And Allelopathy: An Integrated And Sustainable Weed Management Strategy In Sweetpotatoes, Alaina Marie Richardson

Theses and Dissertations

Yellow nutsedge (Cyperus esculentus L.) is a persistent weed in sweetpotato and vegetable cropping systems caused by its aggressive growth habit and limited control options. The present study assessed two alternative, chemical-free methods: steaming the soil and the use of allelopathic cover crops. Greenhouse and field experiments showed that steaming suppressed the germination of yellow nutsedge effectively and that treatments for 45 min provided the highest control of all the soil depths tested (100%). A leachate experiment examined the allelopathy of five cover crops against yellow nutsedge and showed that buckwheat and cereal rye had the largest reductions in shoot …

Feed-Based Strategies To Improve Poultry Production Efficiency, Anna Kathryn Riggs

Theses and Dissertations

The poultry industry continues to make significant strides in efficiency and innovation, particularly through advancements in nutrition. This thesis explores two key areas within broiler nutrition that are essential to supporting sustainable, cost-effective poultry production. First, the potential of a next-generation exogenous carbohydrase enzyme blend containing beta-mannanase and endo-glucanase is investigated when supplemented into reduced-energy, all-vegetable diets based on corn, soybean meal, and corn distillers dried grains with solubles in male broilers over a 42-day grow-out period, including processing (Chapter II). Second, the thesis examines the use of modeling strategies such as cubic, quadratic, kernel and smoothing spline to predict …

Raspberry Cultivar Evaluation Trial In Mississippi, Apphia Santy

Theses and Dissertations

Raspberries (Rubus idaeus) are valued for their flavor, appearance, and nutritional quality. This study evaluated 26 raspberry cultivars over two seasons (2023 and 2024) in Mississippi under a 50% shade-covered system, using organic and conventional fertilization in 7-gallon containers. Cultivars included floricane- and primocane-fruiting types. Data collected included harvest timing, yield, berry weight, soluble solids content (°Brix), titratable acidity, total phenolic content (TPC), and total flavonoid content (TFC). Results showed cultivar differences in yield, berry quality, and antioxidant levels. In 2023, conventionally fertilized plants produced higher yields; in 2024, fertilizer had no impact. Late-season harvests had elevated phytochemicals. ‘Prelude,’ ‘Nova,’ …

Integrated Analysis Of Untargeted Liver, Serum Metabolome And Gut Microbiome Following Selenium Deficiency Diet In Selenoh Knockout And Wildtype Mice, Richard Eugene Baird

Theses and Dissertations

Selenoprotein H (SELENOH) is an oxidoreductase located in the nucleolus, and its biochemical levels decrease with selenium (Se) deficiency, as reported in mammalian research. This current investigation aimed to understand the impact of nutritional Se deficiency on gut microbial composition and metabolomic profiles. The Firmicutes/Bacteroidota (F/B) ratio, linked to various health conditions, was balanced for wildtype (WT) mice (1.06). In contrast, selenoh knockout (KO) mice associated with dietary Se deprivation had a significantly (p < 0.002) lower ratio (0.56), suggesting dysbiosis. It is believed that SELENOH levels decreased due to the Se deficient diet, and the selenoh KO mice exhibited alterations in microbial community composition and metabolite profiles, as supported by correlative analyses. With respect to the bacterial communities, significant differences between diets occurred for three taxa, including Akkemansia mucinphila, Bacteroides caecimuris, and Parabacteroides goldsteinii. Candida tropicalis, Malassezia restricta, and Cyberlindnera jadinii were three abundant fungal yeasts. Only Cyberlindnera jadinii exhibited significantly greater relative abundance between genotypes and was more abundant in the selenoh KO versus WT mice. Correlation analyses between bacterial and fungal taxa revealed both positive and negative relationships, but no specific trends were observed. The liver and serum metabolomic data contained similar amino acids, lipids, proteins, and carbohydrates. Using NMR spectroscopy, 112 liver metabolites were detected, while GC-TOF-MS analysis of the serum revealed the presence of 172, comprising both polar and nonpolar compounds. The metabolite levels varied significantly when analyzed using multivariate models such as PCA and PLS-DA (VIP scores), particularly for glucose, taurine, lactate, and UDP-glucose, which are associated with energy production and cellular health. Overall, the Se deficient diet had the most significant impact on the microbial community structure and the concentration of key metabolites within liver tissues and serum. Correlation analyses conducted across studies revealed significant linear relationships between metabolites and the microbiome. However, these differences were associated with bacterial and fungal taxa containing low relative abundances. Based on these findings, further investigation into the impact of SELENOH homeostasis on microbial and metabolite profiles should be conducted using selenoh KO mice under various nutritional Se dietary levels.

Impact Of Buffered Dry Vinegar And Fermented Onion Juice On The Quality And Shelf-Life Of Fresh Pork Breakfast Sausage, Emily M. Little

Theses and Dissertations

The demand for clean-label meat products has increased interest in natural alternatives to synthetic antioxidants and antimicrobials. This study evaluated the effects of buffered dry vinegar (BDV), fermented onion juice (FOJ), and their combination (CMB) on microbial stability and sensory quality of pork sausage during 9 days of refrigerated storage. Sausages were assigned to control, FOJ (0.5%), BDV (0.5%), or CMB (0.25% each) treatments. BDV and CMB significantly reduced aerobic and psychrotrophic counts by days 7-9, while yeast increased across all treatments over time, reaching ~7 Log CFU/g by day 9. Sensory analysis revealed lower oxidation and off-note intensity in …

Recreation Effects On Soil Carbon, Biocrust Presence, Soil Stability, And Invasive Species In Indian Creek, Bears Ears National Monument, Elisabeth M. Currit

Theses and Dissertations

Desert ecosystems perform essential ecosystem services, including playing a crucial role in the global carbon cycle. Because of this, it is important to understand how recreational activities, common in desert environments, impacts dryland ecosystems' ability to perform ecosystem services. The growing popularity of outdoor recreation in Western US poses a threat to desert ecosystems, and unregulated activities can harm soil health, particularly the presence and functioning of biological soil crusts (biocrusts). This study uses the Indian Creek Special Recreation Management area in Bears Ears National Monument, Utah, USA, as a case study for recreation impacted desert ecosystems. It examines the …

Exploring Soil-Derived Antimicrobials For Inhibiting Dairy-Associated Pathogens And Spoilage Bacteria, Michael Joseph Moran

Theses and Dissertations

Spore-forming bacteria are among the most problematic contaminants in fluid milk. They can survive pasteurization, grow at refrigeration temperatures, and secrete heat-stable enzymes, making them a major cause of spoilage in both pasteurized and reconstituted milk products. Current nonthermal strategies for reducing spore counts, including microfiltration and bactofugation, are often costly and inconsistent. The increasing consumer demand for natural additives in food products has sparked interest in the use of bacterially-derived antimicrobial compounds, particularly those from generally recognized as safe (GRAS) organisms, as an alternative method of dairy preservation. This study explores the antimicrobial potential of ten soil-derived Bacillus and …

Opposing Roles For Iron Transport Systems In Gallium Tolerance In Extraintestinal Pathogenic Escherichia Coli, Nagama Parveen

Theses and Dissertations

Iron is required for bacterial growth because it serves as a co-factor for enzymes involved in DNA synthesis, cellular respiration, and other processes. Disrupting bacterial iron homeostasis is an effective strategy to prevent the growth of antibiotic-resistant bacteria, and gallium (Ga³⁺) has emerged as a promising candidate due to its ability to displace iron (Fe³⁺) and prevent essential iron-dependent pathways. However, Escherichia coli are naturally less sensitive to gallium than many other bacteria, and the mechanisms that control gallium tolerance are not completely understood. To address this, we performed a genome-wide transposon sequencing (TnSeq) screen to identify genes important for …

The Effect Of An Invasive Species (Lantana Camara) And A Fast-Growing Herb (Acanthus Pubescens) On The Plant And Animal Communities In Kibale National Park, Uganda, Kathleen Bufka

Theses and Dissertations

Fast-growing plant species, like Lantana camara and Acanthus pubescens, could threaten biodiversity in Kibale National Park, Uganda. I surveyed plants and wildlife in areas where these plants were frequently encountered compared to those areas where they are infrequent. I found mixed results based on plant traits and the animals considered. My findings support management efforts on these two species to prevent forest degradation.

Acute Exposure Of American Oyster (Crassostrea Virginica) To Selected Antidepressant Drug: Histological, Biochemical, And Immunohistochemical Assessments, Md. Faisal Amin

Theses and Dissertations

The rapid increase in pharmaceutical use has brought significant health benefits to humans. Studies have shown that many pharmaceuticals, such as antidepressants, are often detected in surface waters, groundwater, and even drinking water. These pharmaceuticals in aquatic environments threaten marine life seriously. Marine bivalves are vital source of seafood for people worldwide. In this study, we examined the effects of short-term exposure to fluoxetine, an antidepressant used to treat depression, at low (0.5 μg/L) and high (5 μg/L) doses over a one-week period on American oysters (Crassostrea virginica) under controlled laboratory conditions. Histological analysis revealed atrophy in the gills and …

Assessment Of Floral Resources From Three Tamaulipan Thornscrub Communities Of The Lower Rio Grande Valley, Gracie Makenna Granados

Theses and Dissertations

The Tamaulipan thornscrub is a transition zone between the neotropics and the temperate regions, harboring high biodiversity. This habitat supports a diverse insect community, including many pollinators of native and cultivated plants in Texas and northeastern Mexico. This ecosystem has been extensively degraded and lost; only 5% of its original cover remains north of the Rio Grande. Restoration of the Tamaulipan thornscrub has been ongoing for over three decades, but the important roles of pollinators in the success of such efforts and the functioning of the restored ecosystem have rarely been considered in restoration efforts. The purpose of this study …

Arginine Vasotocin And Corticosterone In Nesting And Non-Nesting Loggerhead Sea Turtles In X’Cacel-X’Cacelito Sanctuary, Krista Blair Reed

Theses and Dissertations

Sea turtles exhibit distinct behaviors before and after egg laying, however, not all individuals successfully oviposit. Some females display disruptions in their typical nesting behavior, returning to the water without laying eggs, which is referred to as a non-nesting emergence (NNE). NNEs can be due to external disturbances on the beach, but why they occur is often unclear. Arginine vasotocin (AVT) is a neuropeptide involved in various physiological processes, including stimulating smooth muscle contraction of the oviduct to facilitate egg deposition in nesting sea turtles. On the other hand, corticosterone is the primary stress hormone in sea turtles and is …

Computational And Experimental Analysis Of Knee Kinematics And Gait Variability: The Effects Of Load, Speed, And Fatigue On Human Motion, Alfirio Trejo Jr.

Theses and Dissertations

This thesis investigates the biomechanical behavior of the human knee under varying conditions of motion, load, and fatigue, with a focus on clinical angle analysis and gait stability. Four studies were conducted using motion capture data and a modified Grood and Suntay Joint Coordinate System (JCS) to evaluate knee joint kinematics—specifically flexion-extension, abduction-adduction, and internal-external rotation. The first study examined the effects of incremental weight loads during isolated knee extension exercises, revealing dose-dependent increases in abduction and internal rotation that may contribute to joint stress. The second study assessed the impact of walking speed and asymmetric loading on gait, showing …

Exploring Transcriptional Stress Responses In Sorghum And Evolutionary Insights Into Yth Domain Proteins Across Plants, Shikha Bharti

Theses and Dissertations

Understanding how plants respond to abiotic stress is crucial for enhancing crop resilience in the face of climate change. This thesis explores plant stress adaptation mechanisms through two interlinked studies that address different aspects of gene regulation. The first study investigates the transcriptional dynamics of Sorghum bicolor under drought and heat stress at 1-hour and 6-hour time points. By employing 3'-end RNA sequencing, this study provides a comprehensive temporal view of gene expression changes, revealing stress-responsive transcription factors, hormone-associated pathways, and chromatin regulators. The comparative analysis highlights both common and distinct molecular responses between drought and heat stress, providing insights …

Biological, Histological, And Immunohistochemical Responses To Heat Stress In Common Goldfish, Carassius Auratus, Ngozichukwu Francis Ngozichukwu

Theses and Dissertations

Global climate change has led to rising temperatures, posing significant challenges to aquatic ecosystems and the health of ectothermic species such as goldfish (Carassius auratus) This thesis investigated the effects of heat stress on growth performance, histological alterations, and molecular stress responses in the gill and kidney tissues of goldfish Fish were exposed to control (24°C), medium (28°C), and high (32°C) temperatures for two weeks Growth parameters, including instantaneous growth rate (IGR), absolute growth rate (AGR), body value gain (BVG), and condition factor, were evaluated alongside histological and immunohistochemical markers of stress Results revealed that high temperature significantly reduced AGR …

Opa1-Mediated Mitochondrial Dynamics In Myogenic Differentiation Of C2c12 Myoblasts, Daniel Eloy Bazan

Theses and Dissertations

Mitochondria play a pivotal role in metabolic energy production, cellular signaling, and apoptosis. To carry out these key cellular roles, mitochondria dynamically balance their organization through opposing including fusion and fission processes. The balance between mitochondrial fusion and fission is regulated by key proteins such as OPA1 (optic atrophy 1) and OMA1 (overlapping activity with metalloprotease). More recently, mitochondria have been increasingly revealed to play key roles in cellular differentiation, where metabolic demands are reprogrammed. This study aims to elucidate the specific roles of OPA1 and OMA1 in the differentiation of C2C12 myoblast cells into myotubes.

Our data demonstrates that …

Phenotypic Plasticity In Response To Abiotic Factors In Silverleaf Nightshade (Solanum Elaeagnifolium), And The Effectiveness Of North American Lacebug (Gargaphia Arizonica Drake And Calvo) As A Biocontrol, Marco Andre Silguero

Theses and Dissertations

Silverleaf nightshade (Solanum elaeagnifolium) is a widespread invasive weed in South Texas and other arid regions, where it reduces crop productivity, competes with native vegetation, and resists conventional control methods. Its ability to thrive across different environments is linked to phenotypic plasticity, allowing it to adjust growth and physiology in response to light and water availability. In this thesis, I examine the role of plasticity in S. elaeagnifolium under field conditions and evaluate the potential of the North American lacebug (Gargaphia arizonica) as a biological control agent. Field observations were used to measure plant traits such as height, stem thickness, …

Molecular And Clinical Insights Into Role Of Gper In Hepatocellular Carcinoma (Hcc), Hossain Ahmed

Theses and Dissertations

Metabolic dysfunction–associated steatotic liver disease (MASLD), encompassing stages from steatosis (MASLD) to steatohepatitis (MASH), cirrhosis, and hepatocellular carcinoma (HCC), is the most prevalent chronic liver disease worldwide, yet molecular markers of progression remain limited. The G protein–coupled estrogen receptor (GPER), a non-genomic estrogen receptor with metabolic and anti-inflammatory roles, emerges as a candidate regulator in hepatic pathophysiology. In this Dissertation thesis, we have delineated for the first time clinicopathological assessment of liver biopsies across MASLD stages revealing a robust inverse correlation between GPER expression and disease severity. Higher GPER levels in early MASLD associated with favorable metabolic and biochemical profiles, …

Transcriptomic Study On The Effect Of Salt Stress In Sorghum Bicolor Seedlings, Joshwa A. Gandy

Theses and Dissertations

The global impact and reliance on cereal crops, and sorghum in particular, is paramount for worldwide food security and for the livelihood of hundreds of millions of people. The detrimental effects of salt stress on crop plants and the huge economic losses it causes by affecting agricultural output worldwide is a devastating issue with huge impacts, which have prompted research to combat salinity in numerous ways. Understanding how cereals respond to the negative effects of salt stress is crucial for enhancing their salt tolerance. In this study of sorghum, we used a 3’-end RNA sequencing approach to elucidate major salt …

Insights Gained From Applying Molecular Techniques To Gray Triggerfish (Balistes Capriscus Gmelin, 1789) In The Mexican Caribbean, The Southern And Northwestern Gulf Of Mexico, Geaceli G. Orive

Theses and Dissertations

This study focuses on Balistes capriscus (Gray Triggerfish), a reef-associated species dependent on hard-bottom habitats in the Gulf of Mexico (GOM). Using mitochondrial DNA barcoding and phylogenetic analyses, genetic structure across four sites was assessed: Rio Grande Valley (RGV), Veracruz, Chinchorro Bank, and Xahuayxol. Samples from RGV and Veracruz exhibited limited haplotype diversity, minimal nucleotide divergence, and weak genetic differentiation-patterns consistent with recent population expansion and ongoing connectivity within the GOM. While the study centered on B. capriscus, all individuals from Chinchorro and Xahuayxol unexpectedly grouped with Canthidermis maculata (Spotted Oceanic Triggerfish), suggesting misidentification, cryptic diversity, or taxonomic uncertainty in …

Analyzing How Taste And Nutrition Impact Learning And Memory In Honey Bees Through Olfactory Associative Conditioning, Alessandra Elizabeth Perry

Theses and Dissertations

Honey bees detect sweet nectar, but not all sweet-tasting sugars provide nutrition. Unlike fruit flies, which can learn to avoid non-nutritious sweet foods, bees may lack this ability. To test if bees form caloric frustration memory (CFM), we conditioned them using odors paired with L-glucose (sweet but non-nutritious) or D-glucose (sweet and nutritious). Bees rewarded with L-glucose showed lower learning and long-term memory compared to D-glucose. Bees cannot differentiate between an odor associated with rewards containing malaise-causing compounds and an odor associated with a reward alone during differential conditioning. Therefore, we used differential conditioning to determine if lower acquisition in …

Comparison Of Recovery Methods After Resistance Exercise For Power Performance, Isaac D. Huerta

Theses and Dissertations

Elite athletes engage in intense training to secure marginal performance advantages, placing considerable physical strain on their bodies. Effective recovery techniques are critical to rapidly restore physical function. Conventional methods like ice baths, hydrotherapy, and massages are often impractical due to cost and logistical barriers. This study examined the efficacy of voluntary deep slow breathing (VDSB) as a cost-effective recovery method compared to static stretching (SS) and no recovery method (control) in untrained male athletes aged 18–26. Using a within-subjects, randomized crossover design over four weeks, participants visited the lab seven times to complete a standardized full-body workout involving plyometric …

Characterizing Host And Viral Factors Relevant To Turkey Hemorrhagic Enteritis Virus-Induced Immunosuppression, Abraham Quaye

Theses and Dissertations

Turkey hemorrhagic enteritis virus (THEV) is an adenovirus (AdV) that causes hemorrhagic enteritis (HE) in turkeys, a debilitating disease affecting predominantly 6-12-week-old turkey poults characterized by immunosuppression (IMS) and intestinal lesions leading to bloody diarrhea. Although a naturally-occurring avirulent THEV strain has been adopted as live vaccine and has proven effective at preventing HE in turkeys, it still retains its immunosuppressive ability. Thus, vaccinated birds are rendered more susceptible to opportunistic infections and death than unvaccinated cohorts, leading to substantial economic losses. This dissertation focuses on elucidating both host and viral factors mediating THEV-induced IMS in turkeys. As THEV gene …

Characterizing Gastric Cancer Tumor Immune Microenvironment Through Extracellular Vesicles, Claire Elizabeth Bruno

Theses and Dissertations

The tumor immune microenvironment (TIME) critically influences cancer progression and determining therapeutic response. As immunotherapies continue to improve and reshape cancer treatments, there is a need for tools that can more efficiently and accurately assess and monitor the TIME. Extracellular vesicles (EVs), especially small EVs (sEVs), are lipid-bound nanoparticles that carry proteins, DNA, and RNA reflective of their cell of origin, offering a novel, non-invasive biomarker of the TIME. This makes them a promising candidate for immune profiling and treatment monitoring in cancer. This thesis investigates the potential of EVs as biomarkers for TIME composition and immune activity. An analysis …

Selenium Nanoparticles Synthesized By Pulsed Laser Ablation In Liquids For Antimicrobial Applications, Tina Hesabizadeh

Theses and Dissertations

This study aimed to synthesize selenium nanoparticles (Se NPs) by Pulsed Laser Ablation in Liquids (PLAL) and investigate their antibacterial and biological effects, particularly their impact on cell viability and related biological responses. Spherical amorphous Se NPs were produced by irradiating a selenium target using a combination of bottom- and top-ablation protocols. After autoclaving, the amorphous Se NPs were converted into trigonal Se NPs. Se NPs were characterized by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The biological effects of Se NPs were quantitatively assessed through evaluations of cell viability and associated …

Transformation With Genes To Improve Lipid Production And Barcoding To Identify Unknown Algal Species, Michelle T. Rada

Theses and Dissertations

With the rising demand for alternative fuels, algal-based biofuels are a promising, sustainable source that meets commercial interest while producing lower greenhouse gas emissions compared to fossil fuels. This thesis explored two studies, evaluating microalgae for their future potential in lipid yield for biofuel production.

The first study involved developing a cost-efficient electroporation protocol that allowed for the genetic transformation of Chlamydomonas reinhardtii using the pChlamy_4 vector, which supports future cloning of genes to enhance lipid production. Parameters affecting DNA uptake and integration into algal genomes were studied: the effect of cell density, the settings of the electroporation device, and …

Detection Of Neuron Derived Cfdna In Blood Plasma: A New Diagnostic Approach For Neurodegenerative Conditions, Chad Alan Pollard

Theses and Dissertations

Neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS) are characterized by the progressive loss of distinct neuronal subtypes, yet current diagnostic tools are either invasive, limited in resolution, or poorly suited for early detection and longitudinal monitoring. This dissertation began with a proof-of- concept study using bisulfite-PCR at a neuron-enriched locus to detect cortical neuron-derived cell-free DNA (cfDNA) in AD plasma samples, establishing the potential of cfDNA as a marker of neuronal injury. Building on these preliminary findings, a novel framework was developed utilizing Oxford Nanopore Technologies (ONT) to profile genome-wide native DNA …

Granulocyte-Colony Stimulating Factor Effects On The Mesolimbic Dopamine Circuitry And Adaptations With Chronic Ethanol Exposure, Rachel Ji-Hyae Campbell

Theses and Dissertations

The mesolimbic dopamine (DA) system contributes to reward and reinforcement learning for ethanol (EtOH). The nucleus accumbens (NAc) receives DA input from the ventral tegmental area (VTA) encoding rewarding information. Acute EtOH increases NAc DA levels, and this DA response is attenuated with chronic EtOH exposure. Furthermore, chronic EtOH results in reduced DA release, increased DA clearance and presynaptic D2-type auto-receptor sensitization. Further research into EtOH-induced neural adaptations that modulate NAc DA release is explored herein, including changes in cholinergic interneurons (CIN), which are known regulators of DA transmission. One potential class of regulators are immune related cytokines, that can …

Academic Wellness In Health Professional Students: The Intersection Between Dietary Attitudes And Behaviors, Sleep Quality, And Mental Health, Kenya Shereece Moore

Theses and Dissertations

Academic success is strongly influenced by student well-being, with nutrition, sleep, and mental health emerging as critical and interconnected components. Health profession students often face significant mental and physical demands, as they navigate their educational training, which can challenge their ability to maintain healthy behaviors and access necessary support. Although these students are often trained to recognize, treat, and promote wellness in others, they may struggle to prioritize or seek care for themselves. This work aims to explore the health behaviors and care-seeking patterns of health profession students, with a focus on dietary habits, sleep, and barriers to mental health …

Investigating The Threshold Of Opa1-Mediated Mitochondrial Fusion In Shsy5y Cells, Jorge Alberto Elizondo

Theses and Dissertations

Mitochondrial dynamics occurring under stress-induced conditions in SHSY5Y neuroblastoma cells provide insight into the OPA1-mediated mitochondrial fusion threshold in cells of varying energetic demands. Mitochondria are dynamic structures that are continuously balancing fusion and fission, depending on cellular needs. The ability to fuse and divide relies on the maintenance of the mitochondrial transmembrane potential. Stress-induced conditions in SHSY5Y cells were induced via utilization of carbonyl cyanide m-chlorophenylhydrazone (CCCP), a protonophore that disrupts the transmembrane potential. OMA1 protein reacts to the loss of transmembrane potential and subsequently cleaves the fusion-active isoforms of OPA1, L-OPA1. This causes an accumulation of S-OPA1, the …