Digital Commons Network^™

Investigating The Relationship Between Hormone Receptors Dax-1 And Estrogen Receptor Within Prostate Cancer Cell Lines, Meghana G. Vijayraghavan

Master's Theses

Prostate cancer (PCa) is estimated to be the second leading cause of cancer-related deaths among men in the United States in 2019. While most prostate tumors rely on androgens for growth signaling, there are subsets of tumors that become androgen-resistant, therefore resisting conventional androgen-depravation therapy. Consequently, research has focused on targeting different hormone receptors for novel therapeutics. One such receptor is Dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (DAX-1). DAX-1 is known to interact with other hormone receptors, such as androgen receptor (AR) and estrogen receptors (ERs) to suppress the proliferative effects …

The Water Table, Soil Moisture And Evapotranspiration Conditions Following The Removal Of Conifers From Two Encroached Meadows, Tyler J. Davis

Master's Theses

Montane meadows provide essential habitat for a variety of unique species and important ecosystem services in the western United States. Although important, meadows have experienced increased rates of conifer encroachment due to climate change, fire suppression and grazing. To combat meadow degradation from conifer encroachment, land managers have employed various restoration strategies one of which is conifer removal. Multiple studies have investigated the relationship between meadow hydrology and vegetation; however, few have assessed the effect of conifer removal on meadow groundwater. The goal of this study is to determine if the removal of conifers from an encroached meadow has an …

Development And Employment Of Environmental Dna Methods For The Detection Of Bull Sharks (Carcharhinus Leucas) In A Freshwater And Estuarine Interface In The Mobile-Tensaw Delta And Mobile Bay, Alabama, Katherine Schweiss

Master's Theses

Species conservation and management is influenced by the quality of monitoring methods employed, especially when targeting elusive, but ecologically significant species, like elasmobranchs. Bull Sharks (Carcharhinus leucas) are highly mobile predators that rely on estuaries and freshwater rivers for maturation, resources, and refuge; their ability to withstand changing environmental conditions may mean they are linking ecosystems through their habitat usage and movements. Rather than setting nets or attaching acoustic monitoring devices, which can be expensive, time-consuming, and invasive, the analysis of environmental DNA (eDNA) for tracing species presence was used to target C. leucasDNA. The present research …

Early Recruitment Of Crassostrea Virginica To Restored And Natural Oyster Reefs In The Western Mississippi Sound: Larval Supply And Post-Settlement Success, Leah Morgan

Master's Theses

The eastern oyster (C. virginica) is a foundation species that improves water quality, protects shorelines, provides refuge for other organisms, and contributes to commercial fisheries. Successful early recruitment of eastern oyster is vital for resupplying adult populations in the face of habitat loss. Coastal oyster populations are challenged by freshwater input, hypoxia, predation and overfishing. Consequently, substantial efforts have been dedicated toward oyster restoration within the northern Gulf of Mexico. The overall objective of this study was to consider the role and importance of early recruitment to oyster restoration in western Mississippi Sound. During the summer 2018 recruitment period, we …

Effects Of Water Table Depth And Edaphic Characteristics On Plant Diversity In A Southern Mississippi Pitcher Plant Bog, Patrick Kirby

Master's Theses

This study examined the effects that water table depth and soil characteristics have on plant species richness and species composition within pitcher plant bogs across seasons. Eight piezometers were installed at random distances to monitor long-term water table depth and pressure fluctuations along a ~710-meter line transect traversing upland and bog habitats. Vegetation sampling quadrats (n=128) were set up near each piezometer. Cover data and water table depths were collected in spring and late summer. Soil samples collected from each treatment group were used to obtain soil texture and nutrient data. The summer collection period yielded a total gdiversity of …

The Thiol Specific Antioxidant (Tsa1) Gene Is Required For Survival In Macrophages And Oxidative Stress Resistance In Histoplasma Capsulatum, Lauren Kennedy

Master's Theses

Histoplasma capsulatum(Hc) is a pathogenic fungus that causes one of the most common invasive fungal respiratory diseases, Histoplasmosis. Histoplasmaundergoes a dimorphic shift from mold to yeast which is crucial to pathogenesis of the organism.

The thiol specific antioxidant gene, Tsa1,is strongly upregulated in the yeast (pathogenic) morphotype. This data led to the hypothesis that this gene plays a role in protecting Hcfrom host mediated oxidative attack. To characterize Tsa1 function, a knockdown strain (tsa1-RNAi) was created by RNAi gene silencing. Expression of Tsa1in the tsa1-RNAistrain was reduced to 10% that …

Distribution, Abundance, And Trophic Ecology Of Anguilliform Leptocephali In The Northern Gulf Of Mexico, Lillian Collins

Master's Theses

All species of anguilliform eels have pelagic leptocephalus larval stages, which provides a means of monitoring the population dynamics of these otherwise cryptic and hard to study species. The goals of this study were to: 1) describe the distribution and abundance of anguilliform eel leptocephali across the northern Gulf of Mexico, and 2) examine the trophic ecology of leptocephali using stable isotope values of carbon and nitrogen (δ13C and δ15N). A 25-year (1990-2014) ichthyoplankton dataset provided by the National Oceanic and Atmospheric Administration (NOAA) Southeast Area Monitoring and Assessment Program (SEAMAP) was used to examine interannual variations in leptocephalus distribution, …

The Effect Of Historic Shipwrecks On Sediment Microbiomes In The Northern Gulf Of Mexico, Melissa Brock

Master's Theses

Microorganisms are ubiquitously distributed across all aquatic habitats, but it is the environmental conditions of a habitat that determine which microorganisms can thrive in terms of abundance or metabolic activity. Habitats that experience consistent physical and chemical environmental conditions repeatedly favor specific taxonomic groups which may result in a microbial assemblage that is commonly associated with that habitat (i.e., a core microbiome). Core microbiomes have been identified for a variety of natural marine habitats including methane seeps, wood falls, octocoral, and deep-sea sediments. However, it was unknown if the presence of man-made structures on the seafloor, including historic shipwrecks, also …

Evaluation Of Pheromone Mating Disruption For California Red Scale Control In Commercial California Citrus, Joel Timothy Leonard

Master's Theses

California red scale (CRS), Aonidella aurantii, is an increasingly injurious insect pest for the California citrus industry due to insecticide resistance, changing weather patterns, and shifting trade regulations. The presence of the insect on fruit, damages the rind of the fruit and high populations can cause dieback of branches as well as lower yields. Pheromone mating disruption of CRS has the potential to alleviate population control concerns and reduce insecticide use. The efficacy of the pheromone mating disruption technique for pest management of CRS was determined using the products CheckMate® CRS and Semios CRS Plus. CheckMate® CRS was evaluated …

Effects Of Intertidal Position On Metabolism And Behavior In The Acorn Barnacle, Balanus Glandula, Kali Horn

Master's Theses

The intertidal zone is characterized by persistent, tidally-driven fluctuations in both abiotic (e.g., temperature, [O₂], salinity) and biotic (e.g., food availability, predation) conditions, which makes this a very physiologically challenging habitat for resident organisms. The magnitude and degree of variability of these environmental stressors differs between intertidal zones, with the most extreme physiological stress often being experienced by organisms in the high intertidal. Given that many of the fluctuating conditions in this environment are primary drivers of metabolic rate (e.g., temperature, [O₂], food availability), we hypothesized that sessile conspecifics residing in different tidal zones would exhibit …

The Democratization And Development Of Cell-Free Protein Synthesis, Max Z. Levine

Master's Theses

Cell-free protein synthesis (CFPS) using crude lysates has developed into a robust platform technology over the last 60 years to express numerous types of recombinant proteins. The open-nature, elimination of reliance on cell viability, and focus of all energy towards production of the protein of interest represent substantial advantages of CFPS over in vivo protein expression methods. CFPS has provided new opportunities across a series of research fields that include metabolic engineering, therapeutic and vaccine development, education, biosensors, and many more. In recent years, optimizations of CFPS have even allowed the platform to reach the industrial level of protein production. …

Diet Quality And Micronutrient Intake In Long-Term Weight Loss Maintainers, Rebecca W. Pascual

Master's Theses

Objective: This study’s purpose was to examine dietary quality, macronutrient intake, and micronutrient adequacy among long term weight loss maintainers (WLM) in a commercial weight management program.

Methods: Participants were 1,207 WLM in WW (formerly Weight Watchers) who had maintained a 9.1 kg or greater weight loss (29.7 kg on average) for 3.4 years, and had an average BMI of 28.3 kg/m². A control group of weight stable adults with obesity (Controls; N=102) had a BMI of 41.1 kg/m² and 2.3 kg or less weight change over the previous five years.

Results: WLM vs. …

Evaluation Of Chilling Efficiency, Meat Tenderness, And Microbial Analysis Of Broiler Carcasses Using Sub-Zero Saline Solutions, Samira Viliani

Master's Theses

The poultry industry is seeking an advanced chilling system that can improve chilling efficiency, microbial safety, and water consumption without compromising meat quality. The objective of this study was to evaluate the effects of sub-zero saline chilling methods on chilling efficiency, breast fillet tenderness and microbial reduction of broiler carcasses. Following evisceration and rinsing, broiler carcasses were randomly assigned to one of three chilling solutions: 1) 0% salt or ice water control (0% NaCl/0.5^oC), 2) 3% salt (3% NaCl/-1.8^oC), and 3) 4% salt (4% NaCl/-2.41^oC) solutions. Broiler carcasses in sub-zero saline solutions reached the …

The Effects Of Cluster Thinning On Vine Performance, Fruit, And Wine Composition Of Pinot Noir (Clone 115) In The Edna Valley Of California, Paul F W Mawdsley

Master's Theses

A three-year study was conducted at a commercial vineyard site in California’s Edna Valley AVA to evaluate the physiological and agronomical effects of the timing of cluster thinning on Pinot noir (clone 115) grapevines. Vines were thinned to one cluster per shoot at three selected time-points during the growing season (bloom, bloom + 4 weeks, bloom + 8 weeks), and fruit from each treatment was harvested and made into wine. Across all growing seasons, yield decreased 43% in thinned vines relative to un-thinned control vines. No effect of cluster thinning or interaction with growing season was found in vine shoot …

Heat Activation Of Bacillus Anthracis Persists Over A Seven Day Period, Nathan T. Ross

Master's Theses

Bacteria of the Bacillus genera are capable of forming dormant and resilient cells called spores in response to starvation. Spores can break dormancy in the presence of nutrients in a process called germination. Historically, spores are exposed to sublethal heat treatments to increase the extent and rate of germination. This process is known as heat activation (HA). Previous studies on Bacillus species indicate the effects of HA are reversible after 72 hours. After this time period, the spores must be reactivated. However, spores of Bacillus anthracis, a member of the Bacillus family, have not been tested to see how long …

The Evolutionary Diversity And Biological Function Of Phenazine Metabolite Biosynthesis In Burkholderia Spp, Samuel Hendry

Master's Theses

Burkholderia encompass a group of ubiquitous Gram-negative bacteria that include numerous saprophytes, as well as several species that cause infections in animals, immunocompromised patients, and plants. Some species of Burkholderia produce colored redox-active secondary metabolites called phenazines (Phz). In the model opportunistic pathogen Pseudomonas aeruginosa, phenazines strongly contribute to the competitiveness, formation of biofilms, and virulence in multiple models of infection. Similar depth of knowledge on the diversity, biosynthesis, and biological functions of phenazines in Burkholderiais missing. This project aimed to bridge this gap in knowledge by focusing on phenazine pathways of B. lata and closely related …

The Ecology And Evolution Of The Freshwater Turtles Of Southern Mississippi, Gabrielle Berry

Master's Theses

Turtles are one of the most threatened group of animals in existence today. The Southeastern United States is one of two global biodiversity hotspots for turtle species, including the state of Mississippi, where over 30 species can be found. However, very few studies have occurred within the state. This lack of research is even more startling given the ongoing decline, or even extirpation, of numerous turtle species across the world, due to a number of factors, including habitat degradation, and harvest for food or the pet trade.

The overarching goal of this project was to perform a species inclusive freshwater …

Acute Cardiovascular Response To Low-Load Unilateral, Bilateral, And Alternating Resistance Exercise With Blood Flow Restriction In The Lower Body, Daphney Stanford

Master's Theses

Resistance exercise with blood flow restriction (BFR) has been suggested to exaggerate the exercise pressor response over traditional non-BFR exercise. While applying BFR relative to an individual’s arterial occlusion pressure (AOP) and exercising at low-loads seems to produce a comparable cardiovascular response to traditional moderate or high-load training, it is beneficial to identify modifications for reducing the cardiovascular response to BFR exercise. PURPOSE: To determine if unilateral (UNI), bilateral (BI), or alternating (ALT) exercise modalities elicit different cardiovascular responses during BFR exercise. METHODS: 18 participants (13 male and 5 female) performed four sets of UNI, BI, and ALT knee-extensions at …

Effects Of Light And Macroinvertebrate Consumers On Detrital Microbial Biofilms In Streams, Cheyenne M. Brady

Master's Theses

In lotic freshwater systems, aquatic macroinvertebrates are key processors of biofilms that grow upon organic matter. Although macroinvertebrate effects on biofilms may depend on light availability, the combined effects of consumers and light remain unexplored. Here, I conducted experiments to test effects of presence/absence of the omnivorous shrimp Macrobrachium ohione and the shredding caddisfly Pycnopsyche sp. on Liriodendron tulipifera litter biofilms in experimental streams under light or darkness. I measured litter-associated algal, fungal and bacterial biomasses and production rates, as well as litter decomposition, over 49 days. Both experiments exhibited significant positive effects of light on algal productivity and interactions …

Influence Of Varying Inorganic Nutrients Supply On Ergosterol And Glucosamine Concentrations And Biomass Nutrient Stoichiometry In Ectomycorrhizal Fungi, Stephanie S. Koury

Master's Theses

Ectomycorrhizal (ECM) fungi are critical for the health of forest ecosystems where they can sequester large amounts of carbon in the form of soil organic matter, a matter of growing interest due to anthropogenic climate change. A clear understanding of their growth dynamics and responses to environmental changes is imperative for future work in forest management and the possible mitigation of increased atmospheric CO₂. Six ECM fungal species were grown in liquid culture under varying nitrogen and phosphorus concentrations and ratios to assess how exogenous nutrient supplies affect fungal biomass stoichiometry and the degree of elemental homeostasis. Additional …

The Effects Of Aqueous Atorvastatin On Steroidogenesis Of Xenopus Laevis At Environmentally Relevant Concentrations, Jeremy Johnson

Master's Theses

Statin drugs are a class of drug that work to reduce endogenous production of cholesterol by competitively inhibiting 3-hydroxy-3-methyl-glutaryl-CoA reductase (Hmgcr) thus inhibiting production of mevalonic acid in the mevalonate pathway. Atorvastatin (Lipitor) is one of the most widely prescribed statin drugs and contamination of wastewater effluent is a growing environmental concern because of the potential to interfere with steroidogenesis in wildlife. Amphibians may be particularly susceptible to the effects of atorvastatin contamination because of their highly permeable integument. I used an amphibian model, Xenopus laevis to test the hypothesis that chronic exposure to low concentrations of atorvastatin …

Infestation Intensities, Attachment Patterns, And The Effect On Host Contest Behavior Of The Tick Ixodes Pacificus On The Lizard Sceloporus Occidentalis, Dylan M. Lanser

Master's Theses

Parasites often have profound effects on the survival and evolution of their hosts, and hence on the structure and health of entire ecosystems. Yet basic questions, such as the degree of virulence of a given parasite on its host, and factors influencing which hosts in a population are at the greatest risk of infection, are vexingly difficult to resolve. The western blacklegged tick-western fence lizard (Ixodes pacificus-Sceloporus occidentalis) system is important, primarily because I. pacificus, a vector of the Lyme disease spirochete Borrelia burgdorferi, is dependent on S. occidentalis for blood meals in its subadult stages, …

Effects Of Sudangrass Cover Crop And Soil Solarization On Weed And Pathogen Management In Organic Strawberry Production, Timothy Jacobs

Master's Theses

Field and lab experiments were conducted to determine the efficacy of sudangrass (Sorghum X drumondii (Nees ex Steud.) Millsp. & Chase) cover crop management techniques and soil solarization on important agricultural weeds and pathogens in organic strawberry production in Central California. Lab experiments assessed the time needed to kill weed seeds at temperatures typically achieved during soil solarization (40°C, 45°C, 50°C, 55°C, and 60°C) in California. Seeds tested included little mallow, redstem filaree, bristly oxtongue, annual sowthistle, common purslane, nettleleaf goosefoot, and redroot pigweed. Efficacy of simulated …

Examining The Effectiveness Of Electromyography Biofeedback At Improving The Upper Trapezius To Serratus Anterior Muscle Activation Ratio, Julia Evelyn Holton

Master's Theses

Purpose: The upper trapezius to serratus anterior muscle activation ratio is essential for optimal shoulder function. An alteration of this ratio, specifically a decrease in upper trapezius and increase in serratus anterior activation, is a main area of focus in shoulder rehabilitation (Kibler, 1998; Paine & Voight, 1993). Electromyography (EMG) biofeedback has been shown to be an effective rehabilitation technique to address many musculoskeletal disorders but there is limited research on the retention of improvements seen with EMG biofeedback (Ma et al., 2011; Lim et al., 2014; Weon, et al., 2011). The purpose of this study was to determine if …

Short Term Shifts In Soil Nematode Food Feb Structure And Nutrient Cycling Following Sustainable Soil Management In A California Vineyard, Holly M. Deniston-Sheets

Master's Theses

Evaluating soil health using bioindicator organisms has been suggested as a method of analyzing the long-term sustainability of agricultural management practices. The main objective of this study was to determine the effects of vineyard management strategies on soil food web structure and function, using nematodes as bioindicators by calculating established nematode ecological indices. Three field trials were conducted in a commercial Pinot Noir vineyard in San Luis Obispo, California; the effects of (i) fertilizer type (organic and inorganic), (ii) weed management (herbicide and tillage), and (iii) cover crops (high or low water requirements) on nematode community structure, soil nutrient content, …

Integrated Aeration For Enhanced Nitrogen Conversion And Removal And The Effect Of Sampling Frequency On Productivity Estimates In Algae-Based Wastewater Treatment Systems, Lauren Parker

Master's Theses

Raceway ponds can be used to cultivate microalgae for purposes such as wastewater treatment and feedstock for animal feeds and biofuels. Besides nitrogen assimilation in biomass, nitrification can be a wastewater treatment mechanism but one that is hindered by the low nighttime dissolved oxygen concentrations (DO) common in wastewater treatment raceways. The large diel difference in pond conditions and changing influent wastewater quality also raises the question of the optimal frequency and timing of grab sample collection, to obtain representative water quality data. Three sets of triplicate pilot raceways (1,000-L, 0.30-m deep, fed primary clarifier effluent) were operated at an …

Development Of A Prolyl Endopeptidase Expression System In Lactobacillus Reuteri To Reduce The Clinical Manifestation Of Celiac Disease, Kara Lynn Jew

Master's Theses

Celiac Disease (CD) is an autoimmune disorder that emerges due to the ingestion of gluten, a protein found in a variety of common grains such as wheat, rye, and barley. Approximately 1 in 100 individuals in the US suffer from CD, making it the most commonly diagnosed gastrointestinal disorder (Ciclitira et. al., 2005). These proline-rich gluten peptides are resistant to proteolysis and accumulate in the duodenum of the small intestine. Once in the duodenum, these peptides illicit an autoimmune response resulting in villous atrophy. Current treatment for CD requires a rigorous adherence to a gluten-free diet. Nevertheless, gluten-containing grains are …

An Analysis Of Changes In Stream Temperature Due To Forest Harvest Practices Using Dhsvm-Rbm, Julia B. Ridgeway

Master's Theses

Forest harvesting has been shown to cause various changes in water quantity and water quality parameters, highlighting the need for comprehensive forest practice rules. Studies show a myriad of impacts to ecosystems as a result of watershed level changes, such as forest harvesting. Being able to better understand the impact that forest harvesting can have on stream temperature is especially critical in locations where federally threatened or endangered fish species are located. The overall goal of this research project is to assess responses in stream temperature to various riparian and forest harvest treatments in a maritime, mountainous environment. The results …

The Effects Of Agricultural Waste-Based Compost Amendments In Organic Pest Management, Gregg T. Stephenson

Master's Theses

Soil-borne pests and pathogens, such as Verticillium dahliae, can devastate a wide range of annual and perennial crops. Current management options for organic production are limited and sustainable management of pathogens, weeds, and arthropods is important for staying profitable and reducing the use of harmful chemicals. Organic soil amendments play an important role in supplying some of the nutritional needs of vegetable crops and improving soil structure, while also contributing to pest control. The objective of this research was to determine the effects of grape and olive-based composts on soil pathogen load, arthropod communities, and weed biomass and diversity. …

The Development Of Diving Capabilities In Weddell Seal (Leptonychotes Weddellii) Pups Throughout Early Ontogeny, Emma Weitzner

Master's Theses

Weddell seals (Leptonychotes weddellii) are among the deepest diving pinnipeds (i.e., seals, sea lions, and walrus) and one of the best studied marine mammals in the world; as such, these seals are considered a model species for the study of diving physiology and behavior. Adult Weddell seal dive physiology is rather comprehensively understood, yet previous research has excluded an examination of pups’ initial independent diving attempts, beginning instead with the diving capabilities of near-weaning individuals at four to five weeks of age. This is beyond the point many pups have attempted their first independent dives; pups begin to …