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open access

Phototoxic Effects of Titanium Dioxide Nanoparticles on Daphnia Magna

Description: Titanium dioxide nanoparticles (TiO2-NP) are one of the most abundantly utilized nanomaterials in the world. Studies have demonstrated the mechanism of acute toxicity in TiO2-NP to be the production of reactive oxygen species (ROS) leading to oxidative stress and mortality in exposed organisms. It has also been demonstrated that the anatase crystalline conformation is capable of catalyzing the cleavage of water molecules to further increase the concentration of ROS in the presence of ultraviole… more
Date: December 2013
Creator: Mansfield, Charles M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Proteomic-Based Assessment of Estrogenic Endocrine Disruption in Hyalella azteca

Description: In our studies, we used the environmentally important crustacean Hyalella azteca (H. azteca) as an invertebrate model and 17β-estradiol (E2) as a representative of environmental estrogenic endocrine disrupting compounds (EDCs) for proteomics-based investigations of endocrine disruptions in an aquatic ecosystem. Using liquid chromatography coupled with tandem mass spectrometry, our investigation focused for the first time on the recognition of biological and molecular events affected by E2 expos… more
This item is restricted from view until January 1, 2029.
Date: December 2023
Creator: Prokai, Marcel Laszlo
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Producing a Film on Oil Spill Research for the Public

Description: The Deepwater Horizon oil drilling rig exploded on April 20, 2010, off the coast of Louisiana in the Gulf of Mexico. Following the spill, British Petroleum, leaser of the rig, set up a funding institution known as the Gulf of Mexico Research Initiative (GoMRI) to support research and understanding of the spill on the environments and peoples of the gulf. This outreach project was created alongside research of the RECOVER consortium, funded by GoMRI, to communicate what is happening within resea… more
Date: December 2018
Creator: Barnes, Emma Katherine
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Integrating Selective Herbicide and Native Plant Restoration to Control Alternanthera philoxeroides (Alligator Weed)

Description: Exotic invasive aquatic weeds such as alligator weed (Alternanthera philoxeroides) threaten native ecosystems by interfering with native plant communities, disrupting hydrology, and diminishing water quality. Development of new tools to combat invaders is important for the well being of these sensitive areas. Integrated pest management offers managers an approach that combines multiple control methods for better control than any one method used exclusively. In a greenhouse and field study, we t… more
Date: December 2011
Creator: Adams, Justin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Photoinduced Toxicity in Early Lifestage Fiddler Crab (Uca longisignalis) Following Exposure to Deepwater Horizon Spill Oil

Description: The 2010 Deepwater Horizon (DWH) oil spill resulted in a large release of polycyclic aromatic hydrocarbons (PAH) into the Gulf of Mexico. PAH can interact with ultraviolet radiation (UV) resulting in increased toxicity, particularly to early lifestage organisms. The goal of this research was to determine the sensitivity of fiddler crab larvae (Uca longisignalis) to photo-induced toxicity following exposure to Deepwater Horizon spill oil in support of the DWH Natural Resource Damage Assessment. … more
Date: December 2015
Creator: Taylor, Leigh M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Changes in Gene Expression Levels of the Ecf Sigma Factor Bov1605 Under Ph Shift and Oxidative Stress in the Sheep Pathogen Brucella Ovis

Description: Brucella ovis is a sexually transmitted, facultatively anaerobic, intracellular bacterial pathogen of sheep (Ovis aries) and red deer (Cervus elaphus). Brucella spp. infect primarily by penetrating the mucosa and are phagocytized by host macrophages, where survival and replication occurs. At least in some species, it has been shown that entry into stationary phase is necessary for successful infection. Brucella, like other alphaproteobacteria, lack the canonical stationary phase sigma factor ?s… more
Date: December 2012
Creator: Kiehler, Brittany Elaine
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Endocannabinoid System in a Planarian Model

Description: In this study, the presence and possible function of endocannabinoid ligands in the planarian is investigated. The endocannabinoids ananadamide (AEA) and 2-arachidonoylglycerol (2-AG) and entourage NAE compounds palmitoylethanolamide (PEA), stearoylethanolamide (SEA) and oleoylethanolamide (OEA) were found in Dugesia dorotocephala. Changes in SEA, PEA, and AEA levels were observed over the initial twelve hours of active regeneration. Exogenously applied AEA, 2-AG and their catabolic inhibition … more
Date: December 2010
Creator: Mustonen, Katie Lynn
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

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

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
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

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
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigation of the Pharmacokinetics of Diazepam in Juvenile Channel Catfish (Ictalurus Punctatus)

Description: The presence of pharmaceuticals in the environment is becoming an increasing regulatory and scientific concern. Thus, the metabolic profile and bioconcentration potential of diazepam, a model benzodiazepine, were examined, as well as effects on the endocrine system in channel catfish. Through the use of specific and non-specific cytochrome P450 (CYP450) inhibitors, it was determined that CYP3A-like enzymes may play a role in the biotransformation of diazepam into temazepam; however, the isoform… more
Date: December 2013
Creator: Overturf, Carmen L.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Ultraviolet Radiation Tolerance in High Elevation Copepods from the Rocky Mountains of Colorado, USA

Description: Copepods in high elevation lakes and ponds in Colorado are exposed to significant levels of ultraviolet radiation (UV), necessitating development of UV avoidance behavior and photoprotective physiological adaptations. The copepods are brightly pigmented due to accumulation of astaxanthin, a carotenoid which has photoprotective and antioxidant properties. Astaxanthin interacts with a crustacyanin-like protein, shifting its absorbance from 473 nm (hydrophobic free form, appears red) to 632 nm (pr… more
Date: December 2011
Creator: Hudelson, Karista
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

Traffic-Generated Air Pollution-Exposure Mediated Expression of Factors Associated with Progression of Multiple Sclerosis in a Female Polipoprotein E Knockout Mouse Model

Description: Environmental air pollution is one risk factor associated with the onset and progression of multiple sclerosis (MS). In this project, we investigated the effects of ubiquitous traffic-generated pollutants, namely a mixture of gasoline and diesel vehicle exhaust (MVE), on signaling pathways associated with the pathophysiology of MS in the central nervous system (CNS) of either ovary intact (ov+) or ovariectomized (ov-) female Apolipoprotein (Apo) E-/-. Specifically, we investigated whether a sub… more
Date: December 2020
Creator: Adivi, Anna
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

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
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Photo-induced Toxicity of Deepwater Horizon Spill Oil to Four Native Gulf of Mexico Species

Description: The 2010 Deepwater Horizon oil spill resulted in the accidental release of millions of barrels of crude oil into the Gulf of Mexico (GoM). Photo-induced toxicity following co-exposure to ultraviolet (UV) radiation is one mechanism by which polycyclic aromatic hydrocarbons (PAHs) from oil spills may exert toxicity. Blue crab (Callinectes sapidus) are an important commercial and ecological resource in the Gulf of Mexico and their largely transparent larvae may make them sensitive to PAH photo-ind… more
Date: December 2015
Creator: Alloy, Matthew Michael
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Maternal Transfer of Dietary Methylmercury and Implications for Embryotoxicity in Fathead Minnows (Pimephales promelas)

Description: Mercury (Hg) is a ubiquitous environmental contaminant, which is capable of global atmospheric transport. As a result, even the most pristine aquatic ecosystems are affected by atmospheric Hg deposition, following which microbial transformation yield organic Hg forms, the most concerning of which is methylmercury (MeHg). Methylmercury is capable of bioaccumulation and biomagnification in food webs, resulting in potentially toxic body burdens due to regular dietary exposure in long-lived organ… more
Date: December 2016
Creator: Bridges, Kristin N.
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
open access

Determination of Bioconcentration Potential of Selected Pharmaceuticals in Fathead Minnow, Pimephales promelas, and Channel Catfish, Ictalurus punctatus

Description: The primary objective of this work was to determine the tissue-specific bioconcentration factors (BCFs) of the selected pharmaceuticals: norethindrone (NET), ibuprofen (IBU), verapamil (VER), clozapine (CLZ) and fenofibrate (FFB) in two freshwater fishes: fathead minnow and channel catfish. BCF tests on fathead followed the standard OECD 42-day test while a 14-day abridged test design was used in catfish exposures. Additional objectives included a) comparing the measured BCFs to the US EPA's BC… more
Date: December 2010
Creator: Nallani, Gopinath C.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Investigating the Effects of Traffic-Generated Air-Pollution on the Microbiome and Immune Responses in Lungs of Wildtype Mice

Description: There is increasing evidence indicating that exposure to air pollutants may be associated with the onset of several respiratory diseases such as allergic airway disease and chronic obstructive pulmonary disorder (COPD). Many lung diseases demonstrate an outgrowth of pathogenic bacteria belonging to the Proteobacteria phylum, and the incidence of occurrence of these diseases is higher in heavily polluted regions. Within the human body, the lungs are among the first to be exposed to the harmful e… more
Date: December 2020
Creator: Daniel, Sarah
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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