Search Results

Factors Affecting MeHg Contamination of Spiders and Insect-Mediated MeHg Flux from Human-Made Ponds

Description: The present study focused on methylmercury (MeHg) in emergent aquatic insects and spiders from human-made ponds. This dissertation addresses two main topics: (1) factors affecting variation in spider MeHg concentrations around human-made ponds and (2) the magnitude of MeHg transported out of human-made ponds by emergent aquatic insects (insect-mediated MeHg flux). Spiders were specifically targeted in this study because they have been proposed as sentinels of MeHg contamination (organism whose … more
This item is restricted from view until January 1, 2029.
Date: December 2023
Creator: Hannappel, Madeline Pratt

The Effect of Developmental Hypoxia on Cardiac Physiology in Three Species: Alligator mississippiensis, Chelydra serpentina, and Danio rerio

Description: In this dissertation, I explored the effects of developmental hypoxia on heart contractility in three separate species of ectotherms: the common snapping turtle (Chelydra serpentina), the American alligator (Alligator mississippiensis), and the zebrafish (Danio rerio). I began with the common snapping turtle and tested whether the utilization of the sarcoplasmic reticulum was altered in response to developmental hypoxia. In the next two chapters, developmental hypoxia of the American alligator … more
This item is restricted from view until January 1, 2025.
Date: December 2023
Creator: Smith, Brandt Ragan

Suburban Succession and Stream Dynamics

Description: Increasingly higher numbers of people are moving into urbanizing environments, yet our understanding of ecosystem consequences of rapid urbanization is still in its infancy. In this dissertation, I assessed dynamics of residential landscapes during suburban succession and consequences for ecosystem functioning. First, I used a space-for-time approach to quantify more than a century of suburban succession in the Dallas – Fort Worth metroplex (DFW). Attributes of residential landscape plant diver… more
This item is restricted from view until January 1, 2025.
Date: December 2023
Creator: McGillewie, Sara B.

Bottom-Up Impacts of Grazing Disturbance on Ground-Nesting Bee Assemblages: Do They Dig It?

Description: In my thesis, I examined impacts of nesting and floral resources on ground-nesting bee assemblages at nine ranch sites with differing grazing histories. Because ecological disturbances can strongly affect the availability of foraging and nesting resources over time, I also examined the impacts of grazing history on nesting and floral resources for ground-nesting bees. I sampled bee assemblages, a comprehensive array of vegetation and soil measures, and floral abundance and richness. I used thes… more
This item is restricted from view until January 1, 2025.
Date: December 2023
Creator: Collins, Shannon Marie

Acute and Sublethal Impacts of Crude Oil Photo-Induced Toxicity in an Early Life Stage Marine Fish (Sciaenops ocellatus) and Invertebrate (Americamysis bahia)

Description: We investigated the modifying effects of ultraviolet (UV) light and chemical dispersant (Corexit 9500A) on crude oil toxicity in juvenile mysids (≤ 24 h) (Americamysis bahia) and larval red drum (24-72 hpf) (Sciaenops ocellatus). These results demonstrate that crude oil toxicity significantly increases with co-exposure to environmentally relevant UV levels in both species, indicating photo-induced toxicity. This toxicity was further exacerbated by the application of chemical dispersants which i… more
This item is restricted from view until January 1, 2025.
Date: December 2023
Creator: Leads, Rachel Renee
open access

Hypoxia-Induced Cardiac Arrest Alters Central Nervous System Concentrations of the GLYT2 Glycine Transporter in Zebrafish (Danio rerio)

Description: Hypoxia as a stressor has physiological implications that have been a focal point for many physiological studies in recent years. In some studies, hypoxia had large effects on the organ tissue degeneration, which ultimately effects multiple ecological processes. These organ tissue studies played a part in the development of new fields like neurocardiology, a specialty that studied the relationship between the brain and the heart. This thesis focuses on how hypoxia-induced cardiac arrest alte… more
Date: July 2023
Creator: Auzenne, Alexis
open access

Detection and Classification of Cancer and Other Noncommunicable Diseases Using Neural Network Models

Description: Here, we show that training with multiple noncommunicable diseases (NCDs) is both feasible and beneficial to modeling this class of diseases. We first use data from the Cancer Genome Atlas (TCGA) to train a pan cancer model, and then characterize the information the model has learned about the cancers. In doing this we show that the model has learned concepts that are relevant to the task of cancer classification. We also test the model on datasets derived independently of the TCGA cohort and s… more
Date: July 2023
Creator: Gore, Steven Lee

Neurotoxic Effects of Polycyclic Aromatic Hydrocarbons in Vertebrates, from Behavioral to Cellular Levels

Description: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental toxicants found in anthropogenic mixtures such as crude oil, air pollution, vehicle exhaust, and in some natural combustion reactions. Single PAHs such as benzo[a]pyrene (BaP) also impact fish behavior when animals are exposed in early life stages and for short periods of time. Aquatic animals such as fish may encounter BaP through road runoff and oil spills, but few studies have examined the impact of aqueous exposure on adul… more
This item is restricted from view until August 1, 2025.
Date: July 2023
Creator: Dunton, Alicia D.
open access

Air Breathing Fish: Development of Air Breathing in Bristlenose Plecos (Ancistrus cirrhosus)

Description: The bristlenose pleco (Ancistrus cirrhosus) is a species of armored catfish in the Loricariidae family that breathes air facultatively when the aquatic environment becomes hypoxic. The bristlenose pleco uses its highly vascularized stomach as an air breathing organ. The two main goals of this developmental study were to determine the size of onset of air breathing and to determine the frequency of air breathing behavior in bristlenose plecos from juveniles to adults. Developing juveniles reach … more
Date: July 2023
Creator: Crowder, Lauren Whitney

Secondary Production of Dragonflies: Comparing Ecosystem Function of Ponds within an Urban Landscape in North Central Texas

Description: The change of land use to include more urban areas is considered one of the main threats to biodiversity worldwide. Urban stormwater retention ponds have been built to collect storm runoff intensified by the increase in impervious surfaces. Although subject to environmental pressures like habitat degradation and pollution, these stormwater retention ponds are diversity hotspots by providing habitat for several aquatic and semi-aquatic species, including dragonflies. Previous research in Dent… more
Date: July 2023
Creator: Stallings, Gillian Carol

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

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
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.

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.
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.

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
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

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
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

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

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

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

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

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
Back to Top of Screen