UNT Theses and Dissertations - 421 Matching Results

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Developmental Effects of a Non-Dioxin-Like Polychlorinated Biphenyl Mixture on Zebrafish (Danio rerio)

Description: PCBs are synthetic organic compounds known for their toxicity to many organisms and are notorious for having large discrepancies between measured and nominal concentrations. Historically thought to be less toxic, non-dioxin-like (NDL) PCBs represent the majority of congeners and are capable of eliciting neurotoxic effects. NDL-PCBs remain understudied, including their effects on aquatic organisms. In the first study, I collected extensive chemistry data and data on neurobehavioral and cardiac e… more
This item is restricted from view until August 1, 2024.
Date: July 2023
Creator: Green, Corey
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

The Impact of Invasive Salmonids on Ecosystem Functioning in South America's Sub-Antarctic Inland and Marine Waters

Description: Invasions from coho salmon were first reported in the Cape Horn Biosphere Reserve (CHBR) in 2019 which is the most southern distribution registered to date. The CHBR is known for its high number of endemic species and unique biodiversity, such as the native fishes Galaxias maculatus and Aplochiton taeniatus. There are now three invasive salmonid species in the rivers of CHBR and are a potential threat to the native fish taxa. Stable isotope and gut content analysis were used to understand resou… more
This item is restricted from view until June 1, 2025.
Date: May 2023
Creator: Moore, Sabrina
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Conservation, Connectivity, and Coexistence: Understanding Corridor Efficacy in Fragmented Landscapes

Description: Conservation corridors, areas of land connecting patches of natural land cover, are frequently cited and implemented as a restorative strategy to counteract fragmentation. Current corridor ecology focuses on experimental corridor systems or designed and built conservation corridors to assess functionality. Such systems and designs are typically short, straight swaths of homogenous land cover with unambiguous transitions between patches. Quantifying the degree to which amorphous landscape config… more
Date: May 2023
Creator: Long, Amanda M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Combined Effects of Polycyclic Aromatic Hydrocarbons and Ultraviolet Light on Benthic and Pelagic Macroinvertebrates

Description: Crude oil commonly enters freshwater aquatic ecosystems as thin sheens forming on the water surface. Oil contains mixtures of toxic compounds called polycyclic aromatic hydrocarbons (PAHs), some of which are known to be photodynamic, increasing toxicity when combined with ultraviolet radiation. Benthic macroinvertebrate communities are commonly utilized as bioindicators, and as such rely on abundant data in literature concerning benthic macroinvertebrates' relative tolerances to a wide range of… more
This item is restricted from view until June 1, 2024.
Date: May 2023
Creator: Chapman, Abigail L.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Greater, Lesser, Guessers: A Look into the Hybridization of Greater and Lesser Prairie-Chickens

Description: My thesis focuses on the conservation consequences of the hybridization of Lesser Prairie-Chickens in Kansas. Specifically, examining how past land management practices altering the species ranges impact the distinctiveness of Lesser Prairie-Chickens. Each chapter is an individual publication that addresses if the Greater and Lesser Prairie-Chicken are distinct when applying the morphological and biological species concepts. Chapter 2 compares the evolutionary history and morphological construc… more
Date: May 2023
Creator: Stein, Carleigh M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Data Mining Using Direct Injection Triple Quadrupole Mass Spectrometry, Infrared Spectroscopy, Inductively Coupled Plasma Optical Emission Spectroscopy, and Polymerase Chain Reaction for the Rapid Identification of Nutraceuticals and Contaminants

Description: There has been a rapid surge toward "organic" products devoid of GMOs, MSGs, and other common compounds found in processed foods that continue to indicate an association with an increased risk for disease. These consumers seek nutrients and vitamins that are lacking in their diet and lifestyle in the form of nutraceuticals for disease prevention and treatment as well as overall lifestyle enhancement. However, these products generally lack clinical evidence as well as legal definition. Due to th… more
Date: December 2022
Creator: Yazici, Micayla Rose Morgan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Migration Tracking, Survival, and Pairing Behavior of American Kestrels Wintering in North Central Texas

Description: The American Kestrel (Falco sparverius) is the smallest and most abundant falcon in North America with a wide geographic range. Unfortunately, surveys have suggested that some kestrel populations have been in decline since the 1950s, though the nominal causes of this decline are unknown. Migratory movement patterns and connectivity have yet to be established for any population of migratory kestrels. In Chapter 2, I investigated methods for attaching migration trackers to kestrels. Specifically,… more
Date: December 2022
Creator: Biles, Kelsey S
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Alterations in the Expression of Proteins Associated with Non-Alcoholic Fatty Liver Disease Observed in the Liver of the C57Bl/6 Wild-Type Male Mouse in Response to Exposure of Mixed Vehicle Emissions and/or High Fat Diet Consumption

Description: Recent epidemiological studies have demonstrated a correlation between the manifestation of non-alcoholic fatty liver disease (NAFLD) and ambient air pollution levels, which is exacerbated by the presence of other risk factors, such as diabetes, dyslipidemia, obesity, and hypertension. We investigated the hypothesis that exposure to a mixture of gasoline and diesel engine emissions (MVE) coupled with the concurrent consumption of a high-fat (HF) diet promotes the development of a NAFLD phenotyp… more
This item is restricted from view until January 1, 2025.
Date: December 2022
Creator: Schneider, Leah Jayne
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Multi-Level Effects of Oxygen Exposure in Endothermic Insects

Description: This dissertation examined the phenotypic plasticity of endothermic, flight and respiratory physiology in response to developmental oxygen exposure in the moth Manduca sexta. Development in both 10% O2 hypoxia and 30% O2 hyperoxia treatments were used to look at the physiological consequence on both ends of the oxygen spectrum. Hypoxic insects reached smaller sizes as adults and had longer pupation lengths than controls. Hyperoxic insects were larger at the end of the larval stage, had increase… more
Date: August 2022
Creator: Wilmsen, Sara M
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Inferring a Network of Horizontal Gene Flow among Prokaryotes Using Complementary Approaches

Description: Horizontal gene transfer (HGT), a mechanism that facilitates exchange of genetic material between organisms from different lineages, has a profound impact on prokaryotic evolution. To infer HGT, we first developed a comparative genomics-based tool, APP, which can perform phyletic pattern analysis using completely sequenced genomes to identify genes are unique to a genome or have sporadic distribution in its close relatives. Performance assessment against currently available tools on a manually … more
This item is restricted from view until September 1, 2024.
Date: August 2022
Creator: Sengupta, Soham
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Regulation of Receptors in Neuronal Cilia with Development, Seizures, and Knockouts: Implications for Excitability

Description: Neurons commonly have a primary cilium, which is a non-motile organelle extending from the centrosome into the extracellular space. In most brain regions, neuronal cilia are enriched in either somatostatin receptor type 3 (SstR3) or melanin concentrating hormone receptor type 1 (MCHR1), or both. The present immunohistochemical study provides novel evidence that primary cilia regulate neuronal excitability via G-protein coupled receptors (GPCRs), and that their identity is governed by brain re… more
This item is restricted from view until September 1, 2027.
Date: August 2022
Creator: Shrestha, Jessica
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Temperature Change and Its Consequences for the Physiology of the Eurythermic Sheepshead Minnow (Cyprinodon variegatus)

Description: The estuarine sheepshead minnow (Cyprinodon variegatus) is the most eurythermic fish species, with a thermal tolerance window between 0.6°C and 45.1°C. However, little is known about the physiological mechanisms that allow this species to survive this temperature range. In order to understand how sheepshead minnow physiology is affected by temperature acclimation and acute changes in temperature, I conducted research on this species using a multi-level approach. I began at the organismal level,… more
Date: August 2022
Creator: Reynolds, Amanda Caroline
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Influence of Hypoxia on Acute Lead Toxicity and Calcium Homeostasis in Early Life Stage Zebrafish (Danio rerio)

Description: The purpose of this study was to investigate the effects of Pb and hypoxia co-exposure on Pb toxicity and Ca homeostasis in early life stage (ELS) zebrafish (Danio rerio). Previous evidence indicates that exposure of ELS zebrafish to hypoxia (~20% air saturation) reduces Ca uptake, likely through down-regulation of the apical epithelial Ca channel (ECaC). Considering that Pb and Ca are known antagonists and compete for uptake pathways, it was hypothesized that co-exposure of Pb with hypoxia wou… more
Date: December 2021
Creator: Moghimi, Mehrnaz
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Production and Optimization of Para-Hydroxybenzoic Acid (pHBA) in Algae Using Metabolic Engineering and Genomics Approaches

Description: Microalgae being photosynthetic and having quick growth cycles can prove to be excellent candidates as biofactories for the production of aromatic compounds like para-hydroxybenzoic acid (pHBA) that act as a monomer in liquid crystal polymers. We developed transgenic lines of the model alga Chlamydomonas reinhardtii by performing nuclear transformation using electroporation. The transgenic cell lines expressed the ubiC gene that utilized chorismate from the shikimate pathway as a substrate to p… more
Date: December 2021
Creator: Saxena, Garima Girish
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Reduced Visceral Fat and Biological Indices of Inflammation Following Combined Prebiotic/Probiotic Supplementation in Free Living Adults

Description: Probiotics/prebiotic supplementation represents a viable option for addressing systemic inflammation and chronic disease risk resulting from excessive body weight. The purpose of this feasibility study was to determine if 90-d of supplementation with prebiotic and probiotic could alter mRNA responsible for inflammation and subsequently metabolic health in weight stable overweight adults. Participants were advised to not change their diet or exercise habits during the study. All protocols were a… more
Date: December 2021
Creator: Tanner, Elizabeth A.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

CO2 Transport and Acid-Base Status during Fluctuations in Metabolic Status in Reptiles

Description: Reptiles can often experience perturbations that greatly influence their metabolic status (e.g., temperature, exercise, digestion, and ontogeny). The most common cause of fluctuations in metabolic status in post-embryonic reptiles is arguably digestion and physical activity (which will be further referred to as exercise). The objective of this thesis is to determine the mechanisms involved in CO2 transport during digestion, determine the mechanisms that allow for the maintenance of acid-base ho… more
Date: December 2021
Creator: Conner, Justin Lawrence
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Investigating the Effects of Inhaled Diesel Exhaust Particles on Gut Microbiome, Intestinal Integrity, Systemic Inflammation, and Biomarkers of Cardiovascular Disease in Wildtype Mice

Description: We investigated the hypothesis that exposure to inhaled diesel exhaust PM can alter the gut microbiome and intestinal integrity, thereby promoting systemic inflammatory response and early CVD risk, which are exacerbated by HF diet. Furthermore, we investigated whether the observed exposure and diet-mediated outcomes could be mitigated through probiotic treatment. We performed an exposure study on C57Bl/6 male mice, placed on either a low fat (LF) diet or a high-fat (HF) diet, and exposed via or… more
Date: December 2021
Creator: Phillippi, Danielle T.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Multiple Dimensions of Fish Functional Traits, Trait Relationships, and Associations with Community Structure and Dynamics

Description: Trait-based approaches are useful in ecological research because of their potential ability to predict species responses from patterns present in the community and to infer mechanisms driving community assembly. Current approaches for fishes are lacking traits across all five fundamental niche dimensions (i.e. habitat, life history, trophic, metabolic and defense). This study quantified a broad range of fish functional traits across all five niche dimensions (commonly used traits and novel trai… more
Date: December 2021
Creator: Harried, Brittany Lee
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Flow-Recruitment Relationships of Smallmouth Buffalo (Ictiobus bubalus) in Three Texas River Basins

Description: This project focused on the relationship between instream flows and smallmouth buffalo (Ictiobus bubalus) recruitment in the Gulf Coastal Plain of Texas. The flow regime is the dominant factor in lotic systems and, consequently, the relationship between instream flows, including impacts to natural flow regimes, and life-history is a subject of growing interest. Smallmouth buffalo is a good model to investigate the relationship between river flows and variable interannual recruitment success of … more
Date: August 2021
Creator: Reeves, Cole Griffin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Analysis of the Accumulation, Toxic Effects, and Risk of Persistent Organic Pollutants in Pinnipeds

Description: The present studies determine the accumulation of persistent organic pollutants (POPs) in three pinniped species, evaluate the relationship with relevant biomarkers of exposure, and calculate toxic effect thresholds. Stranded harp and hooded seals were found to be accumulating PBDEs at levels which could pose a based on threshold levels determined in this study. Northern fur seals are accumulating all three classes of POPs (PCBs, PBDEs, and OCPs) with significant relationships being seen with b… more
Date: August 2021
Creator: Soulen, Brianne K
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Analysis of Multipartite Bacterial Genomes Using Alignment-Free and Alignment-Based Pipelines

Description: In this work, we have performed comparative evolutionary analysis, functional genomics analysis, and machine learning analysis to identify the molecular factors that discriminate between multipartite and unipartite bacteria, with the goal to decipher taxon-specific factors and those that are prevalent across the taxa underlying the these traits. We assessed the roles of evolutionary mechanisms, namely, horizontal gene transfer and gene gain, in driving the divergence of bacteria with single and… more
Date: August 2021
Creator: Almalki, Fatemah
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Sociality in Harris's Hawks Revisited: Patterns of Reproductive Output and Delayed Dispersal

Description: In the lower Rio Grande Valley of south Texas, more than half the nesting groups of Harris's hawks (Parabuteo unicinctus) include at least one auxiliary group member in addition to a breeding pair. To provide further insight into cooperatively breeding raptors, I evaluated sociality in Harris's hawks through the dual benefits framework. I explored the formation, structure, and stability of cooperative group formation across a spatially variable study area, which includes high levels of urbaniza… more
Date: August 2021
Creator: Gibbons, Andrea L
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Benefits of Probiotics on Mortality, Growth Performance, Physiological Condition and Gut Histomophology of Juvenile Red Drum (Sciaenops ocellatus)

Description: Results from the present study found for the first time that the use of bacterial strains of Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium thermophilum, and Enterococcus faecium from the commercial product PrimaLac® had the potential to act as a possible probiotic for juvenile red drum. The addition of PrimaLac® probiotics [whether as a water-soluble probiotic (WSP) or in a probiotic enhanced starter feed (PESF)] reduced mortality (%M), enhanced growth rates (MW, LT, SGR, and … more
Date: May 2021
Creator: Busby, Wren Adell
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Breeding Ecology and Migratory Connectivity of Passerines in the World's Southernmost Forests

Description: In the extensive and remote sub-Antarctic forests of South America, birds are the dominant terrestrial vertebrates. Despite considerable efforts to understand the ecology of birds breeding in these forests, our current knowledge for many species is still incomplete. During three breeding seasons (2014 – 2017), I studied the breeding ecology of the five most abundant open-cup forest-dwelling passerines in the sub-Antarctic forest of Navarino Island, Chile (55°04′S, 67°40′W). There were differenc… more
Date: May 2021
Creator: Jara Millar, Rocio Fernanda
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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