Toxicology Commons^™

Disruption Of Energy Homeostasis By Chemical Mixtures Containing Persistent Pollutants In Hepg2 And C2c12 Cells, Morgan Jacobellis

All Theses

The Environmental Influences on Child Health Outcomes Fetal Growth Studies (ECHO-FGS) birth cohort data was used to identify chemical mixtures associated with adverse outcomes. This biomonitoring study associated specific chemical mixtures in maternal serum with low birth weight or childhood obesity (Pearce et al., 2021). Mixture Profiles 1, 3, and 4, comprised of different observed concentrations of DDE, PCB153, BDE47, and PFOS were prioritized. Mixtures were tested to determine whether they perturbed mitochondrial metabolism and energy sensing pathways. The purpose of this study was to elucidate a potential mechanism linking maternal exposure to mixtures containing persistent organic pollutants (POPs) to …

Developing Aero-Floating Treatment Wetland (Aeroftw) Scaffolds: A Non-Plastic Alternative To Conventional Plastic-Based Ftws, Ada C. Montoya Gomez

All Theses

This research was conducted to explore the possibility of constructing floating treatment wetlands (FTWs) without using plastic materials. FTWs are floating platforms that hold plants on the water’s surface, letting roots dangle within the water column, to help remove contaminants from contaminated water, especially in stormwater ponds. Many conventional FTWs are made with plastic components, such as mats and plastic cup containers, which can release microplastics into the environment over time. The goal of this project was to design and test a new type of FTW that does not depend on plastics to support FTW flotation. The study took place …

The Influence Of Tert-Butylhydroquinone (Tbhq) On Acod1/Irg1-Driven Inflammatory Pathways, Alyssa M. Whisel

All Dissertations

The demand for processed foods has led to increased use of synthetic phenolic antioxidants (SPAs), notably tert-butylhydroquinone (TBHQ), to inhibit lipid oxidation and prolong shelf life. While TBHQ is deemed safe at regulated levels, concerns arise from studies indicating potential adverse effects such as oxidative stress, genotoxicity, and impaired immune function. To investigate TBHQ's immunomodulatory effects, RAW 264.7 murine macrophages were pre-treated with TBHQ and subsequently stimulated with lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly I:C, PIC) to simulate bacterial or viral challenges. Results demonstrated that TBHQ at high non-cytotoxic doses reduced nitric oxide and IL-10 production while promoting phagocytosis and …

Stromal Cells In The Small Intestine: Physiology, Localization, Function, And Alterations Induced By Chronic Arsenic Exposure, Scott Ventrello

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Arsenic is a prevalent toxicant found to affect around 94 to 240 million individuals in over fifty countries who are exposed to levels above the EPA and WHO standard of 10 ppb. As one of WHO’s top ten chemicals of public health concern, it is linked to several chronic diseases including diabetes, obesity, cancers, and inflammatory bowel diseases. Arsenic increases inflammation and disrupts the intestinal barrier in the small intestine and colon. Further, previous studies found that arsenic decreased secretory cell lineage and stromal cell gene expression markers in the small intestine. Thus, our goal was to investigate arsenic’s effect …

Investigation Of Chondrogenesis, Myogenesis, And Osteogenesis After 2,4-Dtbp, 2-Bp, 4-Bp, 3,5-Dtbc Exposure In Zebrafish, Haley Brashears

All Theses

Synthetic phenolic antioxidants (SPAs) are used in personal care products, food packaging, and water pipes, common SPAs include 2,4-di-tert-butylphenol (2,4-DTBP), 2-tert-butyl phenol (2-BP), and 4-tert-butyl phenol (4-BP). These compounds are detected in the environment and in human biological samples. 2,4-DTBP has been detected in cord plasma, placenta, and breast milk samples. This drives the concern regarding developmental toxicity. In human iPS cells 2,4-DTBP impairs differentiation into somites and osteoblasts. Other SPAs, like 2,6-di-tert-butyl-hydroxytoluene caused increased rates of malformations including yolk and pericardial edema, and spinal curvature in 5-day post fertilization (dpf) zebrafish. …

Assessment Of Tce And Chiral Pcb Dechlorination Rate, Congener Diversity, And Enantioselectivity In Town Creek, Sc, Usa Sediment Microcosms, Catherine P. Sumner

All Dissertations

Polychlorinated biphenyls (PCBs) and trichloroethene (TCE) are ubiquitous contaminants and are recognized as persistent organic pollutants due to their extreme chemical stability. PCBs were manufactured by chlorinating biphenyls that created 209 congeners with various structures, of which 19 are chiral and can exist as a pair of stable atropisomers. PCBs have been known to cause developmental and neurological toxicity in humans and wildlife; they can act as endocrine disrupters, carcinogens, and teratogens. Sangamo Weston Inc. was an industrial plant located near Town Creek in Pickens Country, South Carolina, that manufactured capacitors and used Aroclors 1016 and 1254 as dialectic fluids …

Changes In Energy Metabolism Induced By Pfos And Dietary Oxylipins, William Evans

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Perfluorooctanesulfonate (PFOS), an emerging environmental toxicant in addition to 9- hydroxyoctadecadienoic acid (9-HODE) and 9-hydroxyoctadecatrienoic acid (9-HOTrE), endogenously produced oxylipins from polyunsaturated fatty acids (PUFAs) by Cytochrome P450 2B6 (CYP2B6) have been recently associated with hepatic steatosis and peroxisome proliferator- activated receptor signaling by data produced from our laboratory and others. Given the importance of mitochondrial energy metabolism in the maintenance of lipid homeostasis, an array of extracellular flux assays was performed using HepG2 cells to test for the ability of these compounds to disrupt overall mitochondrial activity and respiration associated with fatty acid oxidation and glycolysis specifically. PFOS and …

Role Of Salinity In Perfluorooctane Sulfonate (Pfos) Bioconcentration Between Aquatic Species And The Differential Regulation Of Transporters In Fundulus Heteroclitus, Tyler Davis

All Theses

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant that is known for its surfactant properties and its resistance to degradation. The persistence and lipophilicity of PFOS in surface waters have led to its bioaccumulation in fish, which in turn leads to its accumulation and toxic effects in humans that consume fish. PFOS is also hypothesized to perturb reproduction and survival of low and mid-trophic level zooplankton species such as Daphnia magna that are food for multiple fish species. In this study, a 21-day D. magna chronic toxicity test was performed using 1,10, 100, 1000, and 5000 ppb of PFOS to …

Developmental Effects Of Chronic Low-Level Arsenic Exposure In Mouse Embryonic Stem Cells And In Human Induced Pluripotent Stem Cells, M. Chiara Perego

All Dissertations

Arsenic is an environmental contaminant commonly found in food and drinking water. Exposure to arsenic during embryonic development has been linked to reduced muscle growth, disrupted muscle development and locomotor activity, impaired neurodevelopment, reduced IQ, impaired memory and learning deficits. While the mechanisms responsible for developmental changes following in utero exposure to arsenic are not well known, one possibility is that arsenic might disrupt proper cellular differentiation. Therefore, we aimed to investigate the mechanisms by which arsenic exposure could alter stem cell differentiation into neurons.

First, we continuously exposed P19 mouse embryonic stem (ES) cells to 0.1 μM (7.5 ppb) …

Effects Of 2,4-Di-Tert-Butylphenol On Osteogenic And Myogenic Differentiation Of Human Induced Pluripotent Stem Cells, Thanh-Bình Dương

All Theses

Synthetic phenolic antioxidants (SPAs) are a class of compounds used to increase the durability of polymers as well as to increase the shelf-life of food, cosmetics, and other personal care items. Of these SPAs is 2,4-di-tert-butylphenol (2,4-DBP). 2,4-DBP is primarily used in polyethylene crosspolymer pipes, which are now used as a replacement for the traditional copper pipes for household water distribution. However, 2,4-DBP has been found to leach from these pipes into the water, enabling a mode of exposure to humans. 2,4-DBP has been detected in human urine, serum, but more importantly, maternal serum, placenta, and cord blood. …

Floating Treatment Wetlands For Brackish Waters: Plant Selection And Nutrient Uptake Potential., Andrea Landaverde

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Brackish water bodies in coastal regions provide critical ecosystem services that support human and environmental health. Anthropogenic activities such as agricultural and industrial activities, construction, urban settlements, and tourism contribute to increased inputs of nitrogen (N) and phosphorus (P) in brackish coastal ecosystems. Excess nutrients can lead to impaired water quality and affect marine organisms. Floating treatment wetlands (FTWs) are a vegetated-base technology used to remove contaminants from water column, that has been mainly studied and applied in freshwater systems. Application of FTWs in brackish systems requires further investigation, as high salinity in brackish waters could result in toxicity to …

Toxicity And Effects Of Tire Crumb Rubber In The Aquatic Environment, Stephanie Laplaca

All Dissertations

Plastic materials have provided innovative solutions to society’s evolving needs and challenges. Due to their durability and resistance to degradation, plastics remain in the environment for long periods of time and can therefore be transported to many environmental compartments such as water, sediment, and biota. Microplastics (MPs) have been defined as synthetic plastic particles that have at least one dimension less than 5 mm and are insoluble in water. Microrubber (MR), a recently acknowledged sub-group of MPs, has been documented in environmental samples more recently, frequently comprising a large portion of total MPs of various samples. In South Carolina specifically, …

Comparative Aquatic Toxicity Of A Commercial Naphthenic Acid And Processes For Mitigating Risks, Ciera Kinley

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Comparative toxicity data can inform predictions of relative risk, and can be used to implement strategies for altering exposures to mitigate risk. Naphthenic acids (NAs) are a complex group of carboxylic acids that naturally occur in petroleum sources and energy-derived process waters (e.g. refinery effluents and oil sands process affected waters). These compounds are relatively persistent in water and can be a source of toxicity to aquatic organisms. In the first experiment of this thesis, responses of sentinel aquatic organisms to 7-d exposures of commercial (Fluka) NAs were measured (in terms of acute toxicity) to discern relative sensitivities. In terms …

The Effects Of Indirubin-3’-(2,3 Dihydroxypropyl)-Oximether (E804) On Inflammation Profile In Macrophages, Amy Lauren Anderson

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Indirubin is a deep-red bis-indole isomer of indigo blue, both of which are biologically active ingredients in Danggui Longhui Wan, an ancient Chinese herbal tea mixture used to treat neoplasia and chronic inflammation, and to enhance detoxification of xenobiotics. Multiple indirubin derivatives have been synthesized and shown to inhibit cyclin-dependent kinases (CDKs) and glycogen-synthase kinase (GSK-3β) with varying degrees of potency. Several indirubins are also aryl hydrocarbon receptor (AhR) agonists, with AhR-associated activities covering a wide range of potencies, depending on structure-activity-relationships (SAR). In this study, the effects on indirubin-3’-(2,3 dihydroxypropyl)-oximether (E804), a novel indirubin derivative with potent effects on …

Analysis Of Nanoparticle Exposure On Legionella Pneumophila Biofilm Morphology And Host-Bacteria Interactions, Tara Diane Raftery

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An increase in the amount of money spent on nanotechnology has led to an increase in funding to support nanoparticle (NP) research. Due to their stable, beneficial properties, NPs are found in daily consumer products such as bike frames, socks, cosmetics, and sunscreens. As a result of this, these NPs have the potential to enter the environment and interact with various organisms that play integral roles in the ecosystem as a whole. The effect that NPs have on aquatic systems is largely unknown and understudied. Biofilms are an important structural and functional part of aquatic ecosystems, and comprise various microorganisms …