Search Results

open access

Metabolism and Action of Polyunsaturated N-acylethanolamines in Arabidopsis thaliana Seedlings

Description: The lipoxygenase (LOX) pathway plays an important role in the oxidative metabolism of polyunsaturated N-acylethanolamines (PU-NAEs). The LOX pathway functions in conjugation with hydrolysis by fatty acid amide hydrolase (FAAH) and to produce oxidized NAEs during seed germination and early seedling development. When Arabidopsis seedlings were grown in low micromolar concentrations of lauroylethanolamide (NAE 12:0), growth retardation and elevated endogenous PU-NAE levels were observed due to the… more
Date: August 2015
Creator: Keereetaweep, Jantana
open access

Effects of Macrophyte Functional Diversity on Taxonomic and Functional Diversity and Stability of Tropical Floodplain Fish Assemblages

Description: Multiple dimensions of biodiversity within and across producer and consumer guilds in the food web affect an ecosystem’s functionality and stability. Tropical and subtropical aquatic ecosystems, which are extremely diverse, have received much less attention than terrestrial ecosystems in regards to the effects of biodiversity on ecosystem functioning. We conducted a field experiment that tested for effects of macrophyte functional diversity on diversity and stability of associated fish assembl… more
Date: August 2015
Creator: Treviño, Jessica Marie
open access

The Influence of Urban Green Spaces on Declining Bumble Bees (Hymenoptera: Apidae)

Description: Bumble bees (Bombus spp.) are adept pollinators of countless cultivated and wild flowering plants, but many species have experienced declines in recent decades. Though urban sprawl has been implicated as a driving force of such losses, urban green spaces hold the potential to serve as habitat islands for bumble bees. As human populations continue to grow and metropolitan areas become larger, the survival of many bumble bee species will hinge on the identification and implementation of appropria… more
Date: May 2016
Creator: Beckham, Jessica L.
open access

Biodiversity and Genetic Structure of Benthic Macroinvertebrates Along an Altitudinal Gradient: A Comparison of the Windhond and Róbalo River Communities on Navarino Island, Chile

Description: Altitudinal gradients in Sub-Antarctic freshwater systems present unique opportunities to study the effect of distinct environmental gradients on benthic macroinvertebrate community composition and dispersal. This study investigates patterns in biodiversity, dispersal and population genetic structure of benthic macroinvertebrate fauna across an altitudinal gradient between two watersheds on Navarino Island in southern Chile. Patterns in diversity, density, evenness and functional feeding grou… more
Date: May 2016
Creator: Pulliam, Lauren
open access

Informing Conservation Management Using Genetic Approaches: Greater Sage-Grouse and Galápagos Short-Eared Owls as Case Studies

Description: Small isolated populations are of particular conservation interest due to their increased extinction risk. This dissertation investigates two small wild bird populations using genetic approaches to inform their conservation. Specifically, one case study investigated a Greater Sage-grouse (Centrocercus urophasianus) population located in northwest Wyoming near Jackson Hole and Grand Teton National Park. Microsatellite data showed that the Jackson sage-grouse population possessed significantly re… more
Date: May 2016
Creator: Schulwitz, Sarah E.
open access

The Effects of Neonicotinoid Exposure on Embryonic Development and Organ Mass in Northern Bobwhite Quail

Description: Since their emergence in the early 1990s, neonicotinoid use has increased exponentially to make them the world's most prevalent insecticides. Although there is considerable research concerning the lethality of neonicotinoids, their sub-lethal and developmental effects are still being explored, especially with regards to non-mammalian species. The goal of this research was to investigate the effects of the neonicotinoid imidacloprid on the morphological and physiological development of northern … more
Date: May 2016
Creator: Gobeli, Amanda
open access

Presence of Wolbachia, A Potential Biocontrol Agent: Screening for Vertebrate Blood Meal Source and West Nile Virus in Mosquitoes in the North Texas Region

Description: West Nile virus (WNV) is a geographically endemic mosquito-borne flavivirus that has spread across the United States infecting birds, mosquitos, humans, horses and other mammals. The wide spread nature of this virus is due to the ability of the mosquito vector to persist in broad, ecological diverse environments across the United States. In this study, mosquito populations in North Texas region were sampled for detection of Wolbachia, blood meal source, and WNV. The ultimate goal of this study … more
Date: August 2016
Creator: Adiji, Olubu Adeoye
open access

Maturation of Endothermic Capacity within the Avian Developmental Spectrum: A Characterization of Thermoregulatory Metamorphosis

Description: An avian embryo is ectothermic, with body temperature determined by environmental temperature. Upon hatching, the neonate begins a conversion so that endothermic capacity becomes feasible and body temperature becomes independent of environment. Whole animal metabolic rate and ventilation response, cardiovascular development, and maturation of muscle mitochondrial flux were the focus of this dissertation because of the direct role in shivering thermogenesis. Precocial ducks and altricial Double-… more
Date: August 2016
Creator: Sirsat, Sarah Goy
open access

Identification of a Potential Factor Affecting Graduation Rates in STEM for Hispanic Students at the University of North Texas, via Analysis of Nonfiction Science Books in Spanish Language for ELLs in the Dallas ISD Schools

Description: Latinos are the largest minority group in the U.S.; however despite the continuous growth of the Hispanic population, Latinos are severely underrepresented in STEM fields. One of the reasons that might explain why Latinos do not major in STEM is the way they encounter science curriculum in primary school. Students' limited proficiency in English may constrain their science achievement when instruction is delivered exclusively in English. A quantitative analysis with graduation rates in STEM fro… more
Date: August 2016
Creator: Garcia Colin, Monica
open access

Respiratory Responses in the Freshwater Snail (Pomacea Bridgesii) are Differently Affected by Temperature, Body Mass,and Oxygen Availability

Description: Pomacea bridgesii is a snail species native to tropical and sub-tropical regions, where it usually faces variability in water, temperature and oxygen level. This study of the effect of temperature on mass-specific oxygen consumption (ṀO2) and its relation to body weight shows that the ṀO2 of juvenile snails in normoxia (18-21 kPa) acclimated at temperature of 25°C ranged from 5 to 58 µMol O2/g/h, with a mean of 41.4 ± 18.3 µMol O2/g/h (n=7). Adult snails in normoxia at 25°C show less variat… more
Date: August 2016
Creator: Frifer, Wenasa Salem
open access

Residential Grid-Connected Photovoltaics Adoption in North Central Texas: Lessons from the Solarize Plano Project

Description: Residential Grid-Connected Photovoltaics (GPV) systems hold remarkable promise in their potential to reduce energy use, air pollution, greenhouse gas emissions, and energy costs to consumers, while also providing grid efficiency and demand-side management benefits to utilities. Broader adoption of customer-sited GPV also has the potential to transform the traditional model of electricity generation and delivery. Interest and activity has grown in recent years to promote GPV in north central Tex… more
Date: August 2016
Creator: Jack, Katherine G.
open access

Glucose and Altered Ceramide Biosynthesis Impact the Transcriptome and the Lipidome of Caenorhabditis elegans

Description: The worldwide rise of diabetes and obesity has spurred research investigating the molecular mechanisms that mediate the deleterious effects associated with these diseases. Individuals with diabetes and/or obesity are at increased risk from a variety of health consequences, including heart attack, stroke and peripheral vascular disease; all of these complications have oxygen deprivation as the central component of their pathology. The nematode Caenorhabditis elegans has been established as a mod… more
Date: August 2016
Creator: Ladage, Mary Lee
open access

Cytochrome P450 Gene Expression Modulates Anoxia Sensitivity in Caenorhabditis Elegans

Description: With an increasing population suffering from obesity or Diabetes Mellitus (DM), it is more pertinent than ever to understand how physiological changes impact cellular processes. Patients with DM often suffer from obesity, hyperglycemia, altered fatty acids that contribute to vascular dysfunction, and increased risk to ischemia. Caenorhabditis elegans is a model system used to study the conserved insulin signaling pathway, cellular responses in whole organisms and the impact a glucose diet has o… more
Date: August 2016
Creator: Quan, Daniel L
open access

Influence of a Human Lipodystrophy Gene Homologue on Neutral Lipid Accumulation in Arabidopsis Leaves

Description: CGI-58 is the defective gene in the human neutral lipid storage disease called Chanarin-Dorfman syndrome. This disorder causes intracellular lipid droplets to accumulate in nonadipose tissues, such as skin and blood cells. Here, disruption of the homologous CGI-58 gene in Arabidopsis thaliana resulted in the accumulation of neutral lipid droplets in mature leaves. Mass spectroscopy of isolated lipid droplets from cgi-58 loss-of-function mutants showed they contain triacylglycerols with common l… more
Date: August 2016
Creator: James, Christopher Neal
open access

Analysis of Students' Knowledge, Perceptions, and Interest in Engineering Post Teacher Participation in a National Science Foundation (NSF) Research Experience for Teachers (RET) Professional Development

Description: This study examined the impact of the National Science Foundation's Research Experience for Teachers (RET) in engineering at University of North Texas on students after their teachers' participation in the program. Students were evaluated in terms of self-efficacy, knowledge of engineering, perceptions of engineering, and interest in engineering. A 22-item Likert pre/post survey was used for analysis, and participants included 589 students from six high schools, one middle school, and one magne… more
Date: December 2016
Creator: Reeder, Christina
open access

Exploration of Genome Length, Burst Time, and Burst Size of Streptomyces griseus Bacteriophages

Description: Since phages use the host resources to replicate themselves after infection, the different sizes of the phage genome should influence the replication rate. We, therefore, hypothesized that the smaller genomes should burst the cell faster than the larger ones. As well, the shorter genomes would have greater burst sizes because they should replicate faster. Here, we obtained 16 phages of various genome length. All phages were isolated on Streptomyces griseus and available in our phage bank at the… more
Date: May 2019
Creator: Maneekul, Jindanuch
open access

Exploring Caffeyl-Lignin Biosynthesis in Cleome hassleriana and Polymerization of Caffeyl Alcohol in Arabidopsis thaliana

Description: C-lignin (caffeyl-lignin) is a novel linear lignin polymer found in the seed coats of several non-crop plants, notably Vanilla planifolia (Vanilla), Jatropha Curcas (Jatropha), and Cleome hassleriana (Cleome). C-lignin has several advantages over normal G/S-lignin, found in the majority of lignocellulosic biomass, for valorization in the context of bioprocessing: less cross-linking to cell wall polysaccharides (less recalcitrant biomass), ordered linkages between monomers (homogeneous polymer),… more
Date: December 2019
Creator: Harkleroad, Aaron Djuanell
open access

Key Factors Influencing Retention Rates among Historically Underrepresented Student Groups in STEM Fields

Description: The aim of the study was to identify the factors that have an influence on the completion rates of undergraduate students in the fields of science, technology, engineering and mathematics (STEM). Using Tinto's retention rate theory as the theoretical foundation, data were collected from freshman who were enrolled in the years 2005 to 2008. Results showed gender and first-generation status were significant predictors of STEM completion and time taken to complete the degree. Institutional bias pl… more
Date: December 2018
Creator: Premraj, Divya
open access

Reproduction and Metabolic Responses to Acute and Chronic Hypoxia in Ovoviviparous Blaberid Cockroaches, with a Focus on Blaptica dubia

Description: The major components of the tracheal system of insects are an extension of the exoskeleton, and the size of the exoskeleton is fixed in the adult stage, so any increase in metabolic demand that may accompany reproduction must be met by a relatively unaltered tracheal system that the female set in place at ecdysis, when entering adulthood. Acute hypoxia tends to elicit an increase in ventilation in insects, and here, I observe increased interburst VCO2 release, and a tendency towards a more cont… more
Date: August 2017
Creator: Mallery, Christopher Sean
open access

Development of a Targeted Protein Residue Analysis Approach in Archaeology

Description: Liquid chromatography-mass spectrometry (LC-MS) based proteomic methods have provided archaeologists with a powerful tool for the discovery and identification of proteins within artifacts. Traditionally, discovery-based methods have utilized a non-targeted full mass scan method in an attempt to identify all proteins present within a given sample. However, increased sensitivity is often needed to target specific proteins in order to test hypotheses. Proteins present within archaeological materia… more
Date: August 2017
Creator: Scott, Ashley
open access

The Acute Toxic Effects of the Synthetic Cannabinoid, JWH-018 on the Cardiovascular and Neuroendocrine Systems in Ictalurus punctatus (Channel Catfish)

Description: Cannabinoid (CB) receptors have been found in most vertebrates that have been studied. The location of various CB receptors in the body and brain are known, but their physiological functions are not fully understood. The effects CBs have on the cardiovascular system have been of growing interest in recent years. Increasing reports from emergency departments and law enforcement agencies detail acute cardiovascular and psychological effects from synthetic CB intoxication, such as JWH-018. This ma… more
Date: August 2017
Creator: Taylor, Dedric Esmond
open access

Evaluating the Role of UV Exposure and Recovery Regimes in PAH Photo-Induced Toxicity to Daphina Magna

Description: Polyaromatic hydrocarbons (PAHs) are contaminants synthesized through incomplete combustion of carbon based substances. PAHs are known to be photodynamic and toxicity increases exponentially when in contact with ultraviolet radiation (UV). The effect of UV absent recovery periods and potential for latent toxicity during photo-induced toxicity are previously unknown and are not included within the toxicity model. Results of equal interval tests further support the current reciprocity model as a … more
Date: August 2017
Creator: Gnau, Jennifer Leigh
open access

Neurological Responses to a Glucose Diet in Caenorhabditis elegans

Description: TRPV channels play a role in both mammalian insulin signaling, with TRPV1 expression in pancreatic beta-cells, and in C. elegans insulin-like signaling through expression of OSM-9, OCR-1, and OCR-2 in stress response pathways. In response to a glucose-supplemented diet, C. elegans are know to have sensitivity to anoxic stress, exhibit chemotaxis attraction, and display reduced egg-laying rate. Transcriptome analysis reveals that glucose stimulates nervous system activity with increased transcri… more
Date: August 2017
Creator: Dumesnil, Dennis
open access

Generating Molecular Biology Tools to Investigate the Ca2+ Binding Ability of Arabidopsis TON2

Description: The position of the cell division plane in plants is determined by the position of the preprophase band. The pre prophase band (PPB) is a ring of microtubules centered around the nucleus on the inner side of plasma membrane that establishes the cortical division site. The PPB forms at the end of G2 and breaks down at the end of prophase leaving behind protein markers of its position that are collectively called the cortical division site. During cytokinesis the phragmoplast expands towards the … more
Date: August 2017
Creator: Shao, Danyang
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