Life Sciences Commons^™

Steroid Sulfatase In Rodent Tissues And A Cell Line: Characterization, Regulation And Inhibition, Barathi Balasubramonian

Electronic Theses and Dissertations

Inactive sulfated steroids are present in plasma at higher concentrations than unsulfated ones. Steroid sulfatase (STS) is the enzyme that removes the sulfate group from sulfated steroid hormones in local tissues, making them active. High levels of STS are linked to breast and prostate cancers, and low levels of STS cause behavioral disorders and X-linked ichthyosis. STS is present in most tissues, yet its physiological role is uncertain. We sought to characterize STS activity in several rodent model systems in order to learn more about its function. Three different sets of experiments were conducted. First, we examined STS in mouse …

Macromolecular Crowding Effects On Enzymes That Display Non-Hyperbolic Kinetics, Kelsey A. Aldrich

Electronic Theses and Dissertations

Macromolecules occupy up to 30% of a cell's volume, yet the in vitro study of biological processes is almost exclusively performed in dilute solutions that fail to approximate the crowded interior of a cell. A growing body of literature has identified that macromolecular crowding has significant effects on a number of biochemical processes, including enzymatic activity. However, changes in kinetic parameters with increased macromolecule concentrations have only been determined for enzymes that follow hyperbolic Michaelis-Menten kinetics, despite the fact that over 25% of enzymes deviate from this model. Here, we perform the first characterization of macromolecular crowding effects on …

Chinese Tallow Long-Term Impact On Stand Dynamics In A Bottomland Hardwood Forest Following Vegetation Management, Nicklaus R. Langlois

Electronic Theses and Dissertations

Chinese tallow (Triadica sebifera (L.) Small) is an invasive tree known to have negative impacts on bottomland hardwood forests. Chinese tallow is proficient in reproducing and surviving in bottomland hardwood forests because it is more flood and shade tolerant than most native trees. The long-term effectiveness of Chinese tallow control is an important topic to research as only a few long-term studies of Chinese tallow control have been conducted. A 10-year re-measurement of 22 paired plots installed in 2012 on the Pineywoods Mitigation Bank near Diboll, Texas following herbicide treatments examined Chinese tallow and native tree stand structure. Each …

Rna Secondary Structures: Structure-Function Studies In Viral And Neurodegenerative Diseases, Caylee Cunningham

Electronic Theses and Dissertations

The studies within this dissertation highlight the importance of RNA structure and function, highlighting potential mechanisms in the pathogenesis of the SARS-CoV-2 virus and hallmarks of ALS. Specifically, the s2m, a 41-nt structure found within the hyper variable region of the 3’ UTR of the SARS-CoV-2 virus, was investigated as this element has no definitive role in viruses but its high conservation in several viral families warrants investigation. We used various biophysical techniques to determine if a palindromic sequence in the terminal loop could participate in dimerization activities, which may have implications in recombination and the longevity of the virus. …

Emotional Content In Working Memory Processes: An Fmri Study., Manal Zafar

Electronic Theses and Dissertations

Working memory (WM) is a dynamic system that processes and manipulates both goal-relevant and goal-irrelevant information, integral to higher-level cognition and executive control (Fujii, 2001; Nyberg & Erikkson, 2016). The processing and manipulation of representations is modulated by the affective nature of the information (Pessoa, 2009) such that negative information can either impair or enhance WM processing. WM impairments are seen commonly across clinical disorders such as depression, anxiety, PTSD and schizophrenia (Levens & Gotlib, 2010; Joorman et a., 2011; Brodziak et al., 2015). Specifically, negative information is known to have differential processing in WM compared to neutral and positive …

The Role Of Matrix Metalloproteinase-9 Gene Ablation In Preserving Ejection Fraction During Chronic Volume Overload-Induced Heart Failure., Oluwaseun Ebenezer Akinterinwa

Electronic Theses and Dissertations

Heart failure is a prevalent cause of hospitalization globally, especially among older adults. The ejection fraction is a critical parameter in assessing and managing heart failure patients. As we age, the cardiovascular system undergoes changes that increase the risk of cardiovascular morbidity and mortality. One of the most significant structural features that occur with age is reduced or impaired contractility of the left ventricular wall of the heart. Matrix metalloproteinases (MMPs) play a crucial role in tissue remodeling, and their latency is linked with nitric oxide (NO). In the context of heart failure and constant stress, tissue remodeling leads to …

Epidural Stimulation For Urogenital Dysfunction In The Spinal Cord Injured Rat., Natasha Lorraine Wilkins

Electronic Theses and Dissertations

Spinal cord injury (SCI) is a devastating, life changing event that greatly impacts quality of life. SCI can have body-wide, multi-system consequences including dysfunction within the urogenital system. Challenges with the urinary system include urinary incontinence, urine retention, and detrusor-sphincter dyssynergia all of which require maintenance through the regular use of catheters. Sexual dysfunction in men, who comprise nearly 80% of the SCI population, includes erectile dysfunction, anejaculation, retrograde ejaculation, poor expulsive force during ejaculation, and poor sperm quality. The treatment for sexual function in SCI men is focused more on fertility through the collection of sperm for insemination procedures …

Effects Of A Protection Zone In A Reaction-Diffusion Model With Shifting Bounded Habitat And Allee Effect., Davis Henderson

Electronic Theses and Dissertations

We consider a reaction-diffusion equation that models a population in a shifting bounded habitat with a protection zone and the Allee effect. We assume that the population growth function exhibits the strong Allee effect and has a positive integral within the protection zone (indicating population persistence) and a negative integral in the surrounding patches (indicating population decay). We prove that the existence of steady-state solutions to this system depends on the length of the protection zone. It is demonstrated that there exists some value H* such that, for a protection zone of size H*, there exists a solution and, for …

Establishing A Mouse Model Of Cerebral/Cortical Visual Impairment., Dana K. Oakes

Electronic Theses and Dissertations

Cerebral/cortical visual impairment (CVI) is a disorder most often caused by perinatal hypoxic injury to the developing brain. CVI is the leading cause of childhood visual impairment in developed nations, encompassing deficits in many aspects of vision including visual acuity, contrast sensitivity, and object recognition. The pathophysiology of CVI is not well understood because no animal model currently exists to study this disorder. Because there is no animal model, the pathophysiology of CVI is poorly understood. Here, we developed a murine early postnatal hypoxic model of CVI by exposing mice to 9.5% O₂ at postnatal day (P)3 for a …

Molecular Mechanisms Of Exercise-Stimulated Resolution Of Inflammation And Its Dietary Dependence., Ernesto H. Pena Calderin

Electronic Theses and Dissertations

Diet-induced obesity and adipose tissue (AT) inflammation that ensues sets the stage for systemic metabolic inflammation, disrupted insulin signaling, and eventual type 2 diabetes (T2D) development. At the center of this pathology lies a disruption in endogenous inflammation resolution pathways characterized by an imbalance in lipid mediator production (greater abundance of pro-inflammatory to pro-resolving lipids). Additionally, obese states are characterized by adrenergic deficiency, especially in response to physical activity. Inflammatory processes have been experimentally mitigated by either the pharmacological inhibition of pro-inflammatory signals (i.e., Leukotriene B₄ (LTB₄) and its receptor BLT1, which establishes a potent chemotactic stimulus …

Furthering Ascidian Taxonomy Using Molecular Biology, Nicholas Gulnick

Electronic Theses and Dissertations

Ascidians are our closest invertebrate relatives and comprise nearly 3,000 species separated into three orders: Aplousobranchia (most speciose), Stolidobranchia, and Phlebobranchia (least speciose). Ascidians can be classified as either solitary or colonial organisms. Species delimitation using morphological characters alone has had varied results. Well known, widely distributed, morphological species have turned out to be catch all species comprised of several cryptic species. Molecular markers can help mitigate some of the issues presented by strictly using morphological observations, including resolving the status of cryptic species, and accessing the expert knowledge required to identify a species. By incorporating molecular markers and pairing …

Manipulation Of Cellular Proliferating Cell Nuclear Antigen (Pcna) During Herpes Simplex Virus Type 1 Infection, Jessica Packard, Jill A. Dembowski

Electronic Theses and Dissertations

Herpes simplex virus type 1 (HSV-1) is a double stranded DNA virus that replicates within the nucleus of host cells. Using accelerated native isolation of proteins on nascent DNA (aniPOND), cellular proteins were found to associate with HSV-1 replication forks. One host factor of interest is proliferating cell nuclear antigen (PCNA), the DNA sliding clamp that tethers DNA polymerases and DNA damage response proteins to replicating cellular DNA. Although HSV-1 encodes its own DNA polymerase processivity factor (UL42), PCNA plays a key role in HSV-1 infection. We used commercially available PCNA inhibitors and short hairpin RNAs (shRNA) to investigate how …

Structure-Function Relationships In Neurodegenerative And Infectious Diseases: Biophysical Characterization Of Rna Secondary Structures By Computational Techniques, Kendy Guarinoni

Electronic Theses and Dissertations

The research described in this dissertation focuses on the investigation of the structure and dynamics of regions of RNA implicated in two diseases: COVID-19 and amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). Both studies sought to create experimentally corroborated models that were used to characterize the structure and dynamics of the C9orf72 repeat expansion and the s2m region in coronaviruses, respectively and provided the foundation for future work. In our work involving the s2m region of SARS-CoV-2, the virus responsible for COVID-19, we determined that the homology modeling approach commonly used to derive atomistic structures when no coordinates are available yields a …

Enriching The Pcos Lifestyle, Callie Coleman

Electronic Theses and Dissertations

Polycystic Ovary Syndrome (PCOS) is an endocrine disorder affecting approximately 4 – 20% of women worldwide. It is associated with insulin resistance, fertility problems, and an increased susceptibility to chronic conditions through multiple inflammatory pathways. Women with PCOS are also at increased risk for disordered eating. The Mediterranean diet is associated with decreased inflammation and risk of chronic conditions, and intuitive eating principles are associated with decreased disordered eating patterns. The purpose of this study was to determine if a six-week nutrition education workshop incorporating information and skills related to both the Mediterranean lifestyle and intuitive eating principles can improve …

The Role Of Forest Disturbance And Habitat Characteristics In Shaping Arthropod Ecology., Kane Alec Lawhorn

Electronic Theses and Dissertations

Disturbances in forests often generate dead wood, which is an important resource for a variety of arthropods. In tropical wet forests where fire is rare, lightning and branchfalls are common disturbances that create canopy gaps with associated large amounts of localized dead wood. By contrast, prescribed fire is a common disturbance in temperate forest that creates habitat heterogeneity and widely dispersed dead wood resources. The ecological effects of these disturbances on arthropod communities are largely unknown. This dissertation investigates how disturbance and habitat associations in both tropical and temperate forest shape arthropod ecology. Throughout, I primarily focus on beetles, ants, …

Avian Communities Monitored Along A Successional Chronosequence In Bottomland Hardwood Forests In The Lower Mississippi Alluvial Valley, Eamonn Alasdair Thurmond

Electronic Theses and Dissertations

Bottomland hardwood forests in the Lower Mississippi Alluvial Valley have been extensively reduced due to agriculture conversion and altered hydrology. Remnant forests have undergone further degradation from sources such as a lack of forest management, invasive species, and reduced regeneration of oaks (Quercus spp.). Recent restoration efforts of bottomland hardwood forests have focused on implementing wildlife forestry practices that prioritize restoring wildlife habitat while retaining profitable timber harvests. In this study I surveyed bird communities in bottomland hardwood forests in the Lower Mississippi Alluvial Valley along a successional chronosequence. Birds were sampled using automated recording units over 10 days …

The Functional Role Of The Dynorphin-Kappa Opioid Receptor System In Cocaine-Dependent Male Rats, Jessica Lord

Electronic Theses and Dissertations

Activation of the dynorphin-kappa opioid receptor (KOR) system produces a negative emotional state during drug withdrawal, thereby motivating continued cocaine-seeking behaviors. However, it is not clear whether dynorphin plays a functional role in the onset of compulsive cocaine-taking. Here, escalation of cocaine self-administration was significantly attenuated by pretreatment of a long-acting KOR antagonist, norbinaltorphimine (NBI), in long access (LgA; 6-hours) male rats, whereas there was no effect of NBI on short access (ShA; 1-hour) rats on a fixed or progressive ratio schedule of reinforcement. Additionally, optical density of prodynorphin was increased in the nucleus accumbens (NAc) core and shell, bed …

The Role Of Cardiac Mitochondria In Arrhythmias And Sudden Unexpected Death In Epilepsy In Models Of Dravet Syndrome, Jessa L. Aldridge

Electronic Theses and Dissertations

Dravet Syndrome (DS) is a pediatric epilepsy disorder. Individuals with DS are at increased risk of Sudden Unexpected Death in Epilepsy (SUDEP). One mechanism implicated in the pathology of SUDEP is cardiac arrhythmias. A central element involved in cardiac regulation is mitochondria. In the heart, mitochondria maintain cardiomyocyte energy (ATP) generation and ion homeostasis but also produce harmful reactive oxygen species (ROS) byproducts. We hypothesized that deficits in cardiac mitochondria could underlie arrhythmias and SUDEP in two independent mouse models of DS. Mitochondria produce ATP through the mitochondrial respiratory chain, also called electron transport chain, comprised of a series of …

Pilz Domain-Containing Proteins Regulate Motility In Acinetobacter Baumannii, Gabriel Smith

Electronic Theses and Dissertations

Acinetobacter baumannii is an increasingly multidrug-resistant pathogen contributing to hospital-acquired infections, necessitating a greater understanding of how it interacts with its surroundings. Many bacteria utilize different methods of bacterial motility to move about and interact with these surroundings. A bacterial second messenger, cyclic diguanosine monophosphate (c-di-GMP), can regulate various motility factors that are potentially advantageous for survival in and adaptation to their environment. Concentrations of c-di-GMP are regulated by specific synthesizing and degrading enzymes. Controlled levels of c-di-GMP allow interaction between the c-di-GMP and its binding effectors that induce changes in bacterial phenotypes such as biofilm formation and motility. A …

Characterizing Enterobacter Cloacae Genetic Elements Responsible For Interactions With Candida Albicans, Abigail Suarez

Electronic Theses and Dissertations

Polymicrobial interactions are an important, yet understudied area of research. Candida albicans is the most common human fungal pathogen. The bacterial genus, Enterobacter, is a source of nosocomial acquired infections and increased drug resistance. Our lab has previously discovered that Enterobacter preferentially adheres to C. albicans hyphae. From an E. cloacae transposon library screen, six candidates displayed reduction in C. albicans attachment. These candidates were identified genetically and characterized for involvement in attachment to C. albicans. A fluorescent plasmid was introduced into E. cloacae to measure and observe adherence to C. albicans in planktonic and biofilm growth. In vivo …

Industrial Applications Of Molecular Techniques., Jesse Lee Rozsa

Electronic Theses and Dissertations

Multidisciplinary research is vital in modern science. Combining molecular genetics with engineering disciplines such as material science, robotics, or 3D printing is not a new concept but one that can continue to lead to breakthroughs that will benefit society. Science does not and should not occur in a vacuum, and, in early 2020, the world saw the emergence of a pandemic that shifted the focus of scientific research for a time. This manuscript describes aspects of this journey and the fruit that was born from this historic event. In this dissertation, we used plants and bacteria to produce compounds that …

Unraveling The Complex Dynamics Of Cardiac Fibrosis: Ccn1 As A Novel Regulator Of Scar Collagen Architecture And Structural Integrity In Myocardial Infarction., Annalara Garland Fischer

Electronic Theses and Dissertations

Expansion of the extracellular matrix (ECM), known as fibrosis, accompanies nearly all forms of cardiac disease; however, its most significant and complex manifestations arise following a myocardial infarction (MI). This process, principally led by fibroblasts, constitutes a necessary and adaptive response acutely to fill the void from cardiomyocyte necrosis following ischemic injury due to the heart’s lack of regenerative capacity. This acute response never fully resolves and contributes to ongoing collagen accumulation in non-infarcted regions, leading to diminished ventricular compliance, ongoing myocyte loss, and attrition in function—culminating in heart failure. Further, recent research demonstrates that concomitant with progressive increases in …

Assessing The Impacts Of Soil Arthropods On Geochemical Transformations., Thomas Blake Hudson

Electronic Theses and Dissertations

This thesis contains four individual chapters, two of which highlight studies assessing how arthropods contribute and drive geochemical transformations by directly and indirectly manipulating the availability of anoxic conditions. The first chapter serves as an introduction to the literature on the subject to contextualize the work carried out in later chapters. The second chapter is a field study conducted throughout the summer of 2023 in a lowland tropical rainforest in Costa Rica, where I characterized the temporal and environmental variation impacting greenhouse gas emissions from the nests of leaf-cutting ants (Atta cephalotes). From flux measurements taken across 29 …

Uncovering The Hidden Diversity Of Antibody Heavy Chains And Their Implications For Autoantibody Mediated Disease., Easton Earl Ford

Electronic Theses and Dissertations

Understanding the diversity of antibody (IG) molecules at the DNA and RNA level is imperative for understanding immunological processes and disease. Much of the work to uncover IG diversity has been focused on diversity in the variable region of the IG molecule which is crucial for antigen binding. However, the diversity of the constant region responsible for the functions of IG has largely been ignored in the field of immunogenetics. The work presented in this thesis challenges the dogma that the constant region is invariant in terms of genetic diversity. In this thesis we present the development of a long-read …

Poly (Adp-Ribose) Polymerase-1 (Parp1) Expression In The Frontal Cortex And Hippocampus In Major Depressive Disorder (Mdd) And Suicide, Ramona Faith Fulkerson

Electronic Theses and Dissertations

Major Depressive Disorder (MDD) is a prevalent psychiatric disorder that has a complex pathophysiology. In this study we evaluate the expression of PARP1 and the downstream alarmin protein high mobility group box 1 (HMGB1) in two brain areas that have demonstrated pathology in MDD. MDD donors were compared to controls. MDD subgroups that died by suicide were also compared to those that did not die by suicide. Immunoblotting to determine PARP1 and HMGB1 protein expression was performed in white and grey matter from the frontal cortex and the hippocampus. In BA10 white and grey matter, PARP1 protein expression was significantly …

Effect Of Chemical Enhancers On Transdermal Delivery Of Amiloride For Management Of Resistant Hypertension, Oluwatosin Tabitha Leshaodo

Electronic Theses and Dissertations

Amiloride, a diuretic used for managing resistant hypertension, is hindered by low oral bioavailability and Gastrointestinal side effects, impacting patient compliance. This study investigates transdermal delivery as an alternative to reduce pill burden and improve adherence. Using dermatomed porcine ear skin, the research examined the passive transdermal delivery of amiloride and the effect of various chemical enhancers, including oleic acid, oleyl alcohol, tocopheryl polyethylene glycol succinate, and N-methyl-2-pyrrolidone, individually or in combination. A validated High-Performance Liquid Chromatography method, adhering to Internal Council for Harmonized guidelines (ICH), was employed for quantitative analysis. In vitro permeation studies, conducted using porcine skin and …

Spectral Sensitivity Of Circadian Entrainment In Araneoid And Non-Araneoid Spiders, Craig Campbell

Electronic Theses and Dissertations

Artificial lighting at night is a growing worldwide phenomenon that can negatively impact flora and fauna in the surrounding area. With new technology, there is now opportunity for change: newer LEDs can emit specific wavelengths of light that may be less ecologically damaging. In this study, we aim to describe the circadian spectral sensitivity of two phylogenetically distant urban spider species with similar life histories, the Araneoid Parasteatoda tepidariorum and non-Araneoid Pholcus manueli, to determine differences between them. We exposed these spiders to progressively dimmer levels of white, blue, green, or red light. Despite evidence that spiders lack visual …

An Examination Of The Physical And Technical Demands Of The Competitive Season For Ncaa Division I Male Soccer Players, Emmanuel Espinoza

Electronic Theses and Dissertations

The purposes of this dissertation were to examine the physical and technical demands of collegiate NCAA D-I male soccer players over the course of a competitive season. The following are the major findings of the dissertation:

Study 1 – GPS normative data was calculated by position using data from 5 seasons (2017, 2018, 2019, 2021, 2022). GPS data was compared by position for 5 different GPS-derived metrics. No statistically significant differences were found in any field or lab testing data by position. Statistically significant relationships were found between physical match performance variables of TD and SPR with both YYIRT-1 and …

The Role Of Edc3 In Drosophila Melanogaster Neuronal Development, Keelan Zius

Electronic Theses and Dissertations

Enhancer of mRNA-decay 3 (Edc3) is a component of multiple decapping complexes that regulates the transcriptome by targeting a subset of transcripts for decapping for 5’-to-3’ messenger RNA (mRNA) decay. A missense mutation in the conserved Lsm domain of Edc3 has been reported in two siblings presenting with mild, non-syndromic intellectual disability (ID), however, the role of Edc3 is neuronal development has never been evaluated. Here, we use the Drosophila melanogaster model system to investigate the effects of Edc3 disruption on neuronal development. We found Edc3 reduction leads to significant hyperplasia at the larval neuromuscular junction (NMJ), providing the first …

Evidence Of Climatic Influence On Subsistence Strategies At Sage Hen Springs, Nevada, Andrew Rogers

Electronic Theses and Dissertations

Models of settlement patterns in the northwest Great Basin describe a decrease in residential mobility, intensified use of upland spring ecozones, and an increase in diet breadth during the Middle and Late Archaic. Here, I present data collected from the Sage Hen Springs site in northwestern Nevada during a Phase II testing project conducted by the BLM and an analysis of these data focusing on patterns of subsistence and mobility strategies throughout the Archaic. Results of this analysis support existing models of lifeways in the northwest Great Basin at the small scale and point to climatic factors as influences on …