Search Results

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

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

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

Fatty Acid Amide Hydrolases in Upland Cotton (Gossypium hirsutum L.) and the Legume Model Medicago truncatula

Description: Fatty acid amide hydrolase (FAAH) is a widely conserved amidase in eukaryotes, best known for inactivating the signal of N-acylethanolamine (NAE) lipid mediators. In the plant Arabidopsis thaliana, FAAH-mediated hydrolysis of NAEs has been associated with numerous biological processes. Recently, the phylogenetic distribution of FAAH into two major branches (group I and II FAAHs) across angiosperms outside of Arabidopsis (and in other Brassicaceae), suggests a previously unrecognized complexity … more
This item is restricted from view until January 1, 2025.
Date: December 2023
Creator: Arias Gaguancela, Omar Paul
open access

Glucose-Induced Developmental Delay is Modulated by Insulin Signaling and Exacerbated in Subsequent Glucose-Fed Generations in Caenorhabditis elegans

Description: In this study, we have used genetic, cell biological and transcriptomic methods in the nematode C. elegans as a model to examine the impact of glucose supplementation during development. We show that a glucose-supplemented diet slows the rate of developmental progression (termed "glucose-induced developmental delay" or GIDD) and induces the mitochondrial unfolded protein response (UPRmt) in wild-type animals. Mutation in the insulin receptor daf-2 confers resistance to GIDD and UPRmt in a daf-1… more
Date: December 2023
Creator: Nahar, Saifun
open access

Investigating Novel Streptomyces Bacteriophage Endolysins as Potential Antimicrobial Agents

Description: As antibiotic resistance has become a major global threat, the World Health Organization has urgently called scientists for alternative strategies for control of bacterial infections. Endolysin, a protein encoded by a phage gene, can degrade bacterial peptidoglycan (PG). Currently, there are three endolysin products in the clinical phase. We, thus, are interested in exploring novel endolysins from Streptomyces phages as only a few of them have been experimentally characterized. Using bioinforma… more
Date: December 2023
Creator: Maneekul, Jindanuch

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.
open access

Anti-S2 Peptides and Antibodies Binding Effect on Myosin S2 and Anti-S2 Peptide's Ability to Reach the Cardiomyocytes in vivo and Interfere in Muscle Contraction

Description: The anti-S2 peptides, the stabilizer and destabilizer, were designed to target myosin sub-fragment 2 (S2) in muscle. When the peptides are coupled to a heart-targeting molecule, they can reach the cardiomyocytes and interfere with cardiac muscle contraction. Monoclonal antibodies, MF20 and MF30, are also known to interact with light meromyosin and S2 respectively. The MF30 antibody compared to anti-S2 peptides and the MF20 antibody is used as a control to test the central hypothesis that: Both … more
Date: July 2023
Creator: Quedan, Duaa Mohamad Alhaj Mahmoud
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

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

Identification and Characterization of Genes Required for Symbiotic Nitrogen Fixation in Medicago truncatula Tnt1 Insertion Mutants

Description: In this dissertation I am using M. truncatula as a model legume that forms indeterminate nodules with rhizobia under limited nitrogen conditions. I take advantage of an M. truncatula Tnt1 mutant population that provides a useful resource to uncover and characterize novel genes. Here, I focused on several objectives. First, I carried out forward and reverse genetic screening of M. truncatula Tnt1 mutant populations to uncover novel genes involved in symbiotic nitrogen fixation. Second, I focused… more
This item is restricted from view until August 1, 2028.
Date: July 2023
Creator: Cai, Jingya

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.

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

Role of MicroRNAs and Their Downstream Targets in Zebrafish Thrombopoiesis

Description: Previous studies have shown that human platelets and megakaryocytes carry microRNAs suggesting their role in platelet function and megakaryocyte development, respectively. However, there is limited information on microRNAs' role in zebrafish thrombopoiesis. Zebrafish thrombocytes could be used as a model to study their role in megakaryocyte maturation and platelet function because thrombocytes have both megakaryocyte features and platelet properties. In our laboratory, I identified 15 microRNAs… more
This item is restricted from view until June 1, 2025.
Date: May 2023
Creator: Al Qaryoute, Ayah

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

Identification and Characterization of Two Putative Sulfate Transporters Essential for Symbiotic Nitrogen Fixation in Medicago truncatula

Description: The process of symbiotic nitrogen fixation (SNF) in legume root nodules requires the channeling and exchange of nutrients within and between the host plant cells and between the plant cells and their resident rhizobia. Using a forward genetics approach in the Medicago truncatula Tnt1 mutant population followed by whole genome sequencing, two putative sulfate transporter genes, MtSULTR3;5 and MtSULTR3;4b, were identified. To support the hypothesis that the defective putative sulfate transporter … more
This item is restricted from view until January 1, 2025.
Date: December 2022
Creator: Pradhan, Rajashree

Investigating the Spatial Relationship between Suicide and Race/Ethnicity: The Case for Alternate Rate Adjustment Techniques in Medical Geography

Description: This work explores potential distortions created by race and ethnicity on the visualization, interpretation, and understanding of the spatial distribution of suicide in the United States. Due to radically different suicide rates among racial/ethnic groups, traditional crude or age-adjusted rates may introduce statistical confounding in both linear and spatial models. Using correlation, choropleth mapping, hot spot analysis, and location-allocation modeling, this work shows how traditional metho… more
Date: December 2022
Creator: Lester, Katherine Ann

Medicago truncatula NPF1.7: Structure-Function Assessment and Potential as a Phytohormone Transporter

Description: In Medicago truncatula, the MtNPF1.7 transporter has been shown to be essential for root morphology and nodulation development. The allelic MtNPF1.7 mutants, Mtnip-1 (A497V), Mtnip-3 (E171K), and Mtlatd (W341STOP), show altered lateral root growth and compromised legume-rhizobium symbiosis. To assess the role of a series of distinct amino acids in the transporter's function, in silico structural predictions were combined with in planta complementation of the severely defective Mtnip-1 mutant pl… more
Date: December 2022
Creator: Yu, Yao Chuan
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
open access

Acute Toxicity of Crude Oil Exposures to Early Life Stage Teleosts: Contribution of Impaired Renal Function and Select Environmental Factors

Description: Oil spills are well-known adverse anthropogenic events, as they can induce severe impacts on the environment and negative economic consequences. Still, much remains to be learned regarding the effects of crude oil exposure to aquatic organisms. The objectives of this dissertation were to fill some of those knowledge gaps by examining the effects of Deepwater Horizon (DWH) crude oil exposure on teleost kidney development and function. To this end, I analyzed how these effects translate into pote… more
Date: August 2022
Creator: Bonatesta, Fabrizio
open access

Assessing Student Perceptions in Short Research Experiences and Course Research Experiences in Undergraduate Biology Laboratories

Description: This study examined students' perception between short research experiences (SRE) courses and full-semester course research experiences (CRE) using the Persistence in the Sciences (PITS) survey and the interview questionnaire. The study also aimed to correlate the influence of student's demographic as a predictive indicator for Project Ownership Scores (POS) and Quantitative Literacy (QL) score means. The three courses studied at the University of North Texas were Biology for Science Majors Lab… more
Date: August 2022
Creator: Alberts, Arland Dulcey

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
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

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
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