Life Sciences Commons^™

Investigation Of The Environmental Factors Regulating The Biomass And Toxin Production Of The Benthic Cyanobacterium Microseira Wollei In Lake Wateree, South Carolina, Kara Clyburn

Theses and Dissertations

Impacts from anthropogenic activities and climate change are significantly altering nitrogen (N) cycling processes and biological productivity along the freshwater to marine continuum, and the acceleration rate of excessive N and phosphorus (P) concentrations entering aquatic environments is unprecedented. As a result, nutrient pollution is contributing to the increasing magnitude and duration of cyanobacterial harmful algal blooms (cHABs), oxygen (O2) depletion, loss of biodiversity, and impacts to human and ecosystem health. Lake Wateree, South Carolina (SC) is a freshwater drinking and contact recreational water resource with elevated symptoms of eutrophication, including the increasing prevalence of the N2 fixing benthic cyanobacterium …

The Interaction Of Sodium Fluoride And Sodium Selenate On The Developmental Toxicity To Xenopus Laevis And Ambystoma Maculatum Embryos, Shelby Wolfram

Theses

Amphibians play critical roles in the environment's wellness. Fluoride (F) is a widely existing environmental pollutant. It is commonly known for being added to drinking water and as a topical dose on teeth. Selenium (Se) can be found in organic and inorganic forms in nature. Many different fertilizers, pesticides, insecticides, and fungicides contain sodium selenate in them. The range selenium has between deficiency and toxicity is narrow, meaning excess exposure could cause various adverse effects in aquatic organisms. Xenopus laevis is a standard model for developmental toxicity due to being minimal maintenance, cost efficient, and having transparent embryos. Xenopus makes …

Quantifying The Toxicological Effects Of The Organic Uv Filters Avobenzone And Homosalate On Acropora Cervicornis, Samantha F. Buckley

All HCAS Student Capstones, Theses, and Dissertations

Reports of the environmental effects of organic UV filters such as oxybenzone have led to the marketing of “reef-safe” sunscreen ingredients, including avobenzone and homosalate. Avobenzone provides broad-spectrum UV protection which blocks higher wavelength UV rays, the leading cause of aging and skin cancer. However, as polycyclic aromatic hydrocarbons (PAHs), organic UV filters have similar structures to crude oil and estrogens, some of which have been labeled endocrine disrupters. Common in personal care products, UV filters enter marine ecosystems via wastewater effluent and swimmers. Significant stress and mortality have been observed in juvenile and some adult scleractinian corals after exposure …

Health Effects Of Neonicotinoids On An Agricultural Community, Jocelyn Rodriguez-Paar

Capstone Experience

Mead, Nebraska, a small United States agricultural community consisting of approximately 600 people, was accidentally exposed to high amounts of neonicotinoids when AltEn, an ethanol plant that used neonicotinoid coated corn and soybean seeds for biofuel, was discovered not disposing of the toxic byproduct safely. Coincidentally, there was also a leak in their wastewater system that also contaminated the nearby areas. Although neonicotinoids are not considered highly dangerous with low dose exposures, large dose exposures can cause symptoms similarly to nicotine poisonings, such as difficulty breathing, vomiting, nausea, hypertension, tachycardia, and lethargy (Imamura, T. et al., 2010). Neonicotinoid poisoning can …

Toxicological Assessment Of Zinc Oxide And Titanium Dioxide On Staghorn Coral, Acropora Cervicornis, Katherine E. Meurer

All HCAS Student Capstones, Theses, and Dissertations

Coral reefs are one of the most diverse and biologically significant ecosystems on the planet. However, anthropogenic impacts have led to a global decline in overall reef health in recent years. To address concerns that organic ultraviolet filters in sunscreen may contribute to reduced coral health, the mineral UV filters, zinc oxide (ZnO) and titanium dioxide (TiO₂), have become more common in sunscreen formulas as they are often considered “reef safe” despite limited information on the toxicological effects of these compounds in corals. This study evaluated the effects of exposure to unmodified forms of zinc oxide or titanium …

Toxicity Of The Technology Critical Elements Germanium And Yttrium To Daphnia Magna And Hyalella Azteca And The Influence Of Toxicity Modifying Factors, Rashid Shah

Theses and Dissertations (Comprehensive)

Technology critical elements (TCEs) are increasingly used in high and green technologies but there is little aquatic toxicity data for TCEs, particularly in fresh water. The objective of this study was to investigate the toxicity of two TCEs, Ge and Y, to Daphnia magna and Hyalella azteca and to understand the role of natural organic matter and cations on toxicity modification. Testing followed standard methods. The 48 h EC50 for D. magna was 11.6 (95% CI of 9.64-13.8) mg Ge/L based on measured dissolved concentrations at test end. The addition of NOM at 10 mg DOC/L resulted in a significant …

The Interactive Effects Of Nontoxic Levels Of Microplastics - Textile Microfibers And Tire Wear Particles, On The Acute Toxicity Of Bifenthrin In The Estuarine Grass Shrimp, Palaemonetes Pugio, Xiaoxuan Fan

Theses and Dissertations

Contemporary pollution issues are primarily focused on Contaminants of Emerging Concern (CECs) which may include Brominated and Fluorinated flame retardants, Pharmaceuticals and Personal Care Products (PPCPs), Contemporary Use Pesticides (CUPs), nanomaterials and microplastics (Muraya et al., 2014). Tire wear particles and textile microfibers are examples of CECs which may gradually increase in the environment and may cause adverse effect on the health of some aquatic species (Marwood et al., 2011; Taylor et al., 2016). Microplastic particles are so small that they can be ingested by many marine species such as filter feeders and small particle feeders including mollusk and crustaceans, …

The Effect Of Circadian Clock Modulation On Cisplatin Cytotoxicity, Nadeen Nibal Ahmad Anabtawi

Browse all Theses and Dissertations

Cisplatin is a DNA damage-based chemotherapeutic drug widely used to treat various types of cancers; however, the treatment's toxicity restricts its efficiency. Studies have shown that the circadian rhythm controls the DNA damage response and affects the repair pathways of cisplatin-induced DNA damage. Circadian clock modulation, therefore, has been proposed to be a potential mechanism for enhancing cisplatin tolerability. Here we used clock-enhancing molecules to evaluate the effect of pharmacological clock modulation on cisplatin cytotoxicity. Using cultured human cell lines, cisplatin cytotoxicity was found to be attenuated following treatment with circadian-enhancing molecules KS15 and SR8278. Moreover, the protein and mRNA …

Potential Toxicity Of Silver Nanoparticles To Microbial Communities And Macroinvertebrates, Joseph Kusi

Electronic Theses and Dissertations

Silver nanoparticles (AgNPs) are the most common nanomaterials incorporated in commercial products due to their antimicrobial activity. Recently, AgNPs were detected in surface waters suggesting the potential for bioavailability in the aquatic receptor organisms. This dissertation research attempts to understand the potential toxicity of AgNPs on water quality indicators, focusing on the microbial community and amphipods. This study evaluated whether: (1) the antimicrobial properties of AgNPs pose potential risks to microbial communities in pathogen impaired streams; (2) AgNPs can cause a shift in functional diversity and metabolic fingerprinting of microbial communities; (3) survival and growth of Hyalella azteca (amphipods) could …

Understanding The Toxicity Of Single Hydrocarbons, Oil, And Dispersed Oil: A Species Sensitivity Assessment For Five Atlantic Coral Species, Nicholas R. Turner

HCNSO Student Theses and Dissertations

Coral reefs are keystone coastal ecosystems that are at risk of exposure to petroleum hydrocarbons from a range of sources, including oil spill incidents and chronic runoff, and are usually one of the highest valued natural resources for protection in Net Environmental Benefit Analysis (NEBA)/Spill Impact Mitigation Assessment (SIMA) of response methods and environmental damage. Previous research evaluating hydrocarbon impacts to corals has resulted in no clear characterization of sensitivity, as work has generally focused on higher-level effects, compounded by significant variability in experimental methodology. This represents an important knowledge gap in oil spill preparedness and response as it relates …

The Effects Of Climate Change On The Ecotoxicology Of Contaminants Of Emerging Concern: Flame Retardants, Contemporary Use Pesticides And Pharmaceuticals Personal Care Products On The Estuarine Grass Shrimp, Palaemontes Pugio, Rajaa Nouri Al-Yassein

Theses and Dissertations

Global Climate Change may adversely affect the environment, increasing water temperature and altered salinity which may affect the toxicity of both legacy pollutants and Contaminants of Emerging Concern (CECs). Acute, 96 hour toxicity tests with adult grass shrimp (Palaemonetes pugio) assessed the effects of CECs (Polybrominated Diphenyl Esther (PBDE) – 47, ibuprofen, bifenthrin, triclosan, and bifenthrin/triclosan mixtures) under Standard Conditions (20°C, 20psu) and different Climate Change Conditions (30°C, and/or35psu) In addition, the grass shrimp microbiome (e.g. Vibrio bacteria) were assessed following acute triclosan exposures at the Maximum Exposure Concentration (MECs) and Minimum Inhibitory Concentration (MICs) under standard conditions. …

Effects Of E-Cigarette Flavoring Chemicals On Human Macrophages And Bronchial Epithelial Cells, Anna Manzi Morris

Graduate Theses, Dissertations, and Problem Reports

E-cigarettes and vapes are relatively new devices which are popular among young adults and teens. These devices vaporize an “e-liquid” for the user to inhale, which typically contains a mixture of propylene glycol (PG), vegetable glycerin (VG), varying concentrations of nicotine, and flavoring chemicals. Due to these flavoring chemicals being intended for ingestion as a food additive, their respiratory health effects are not well understood. Thousands of e-cigarette flavors are available on the market, many of which have the potential for toxicity. The majority of e-liquid flavoring chemicals (ELFCs) have not been tested for inhalation safety. In this study, we …

Critical Physicochemical Properties For Nanoparticle Toxicity: Impact Of Surface Coating And Size On Particle-Induced Cell Transformation And Inflammatory Response, Tiffany Kornberg

Graduate Theses, Dissertations, and Problem Reports

Nanoparticles, which measure 100 nm in at least one dimension, have surged in development, production, and use for a wide range of applications. However, the rapid pace of development for these emerging materials with unclear/unknown toxicity profiles makes it difficult to adequately assess health risk associated with exposure. One critical obstacle which limits scientific research to fill these critical knowledge gaps is the lack of accurate and predictive models for nanotoxicology studies, particularly those which involve occupationally relevant exposure scenarios (pulmonary exposure to low dose of particles in the circulating air). Typically, animal models are used to assess potential systemic …

Development And Evaluation Of Biocompatible Engineered Nanoparticles For Use In Ophthalmology, Bedia Begum Karakocak

McKelvey School of Engineering Theses & Dissertations

The synthesis and design of biocompatible nanoparticles for targeted drug delivery and bioimaging requires knowledge of both their potential toxicity and their transport. For both practical and ethical reasons, evaluating exposure via cell studies is a logical precursor to in vivo tests. As a step towards clinical trials, this work extensively investigated the toxicity of gold nanoparticles (Au NPs) and carbon dot (CD) nanoparticles as a prelude to their in vivo application, focusing specifically on ocular cells. As a further step, it also evaluated their whole-body transport in mice. The research pursued two approaches in assessing the toxicity of engineered …

Test Of Bpa's Estrogenic Effects On Brain Aromatase Expression, Neural Activity, And Locomotive Behavior In Zebrafish Larvae, Ryan J. Mcauley

Cal Poly Humboldt theses and projects

Bisphenol A (BPA) is a well-known endocrine disrupting chemical that mimics the effects of estrogens. Aromatase B (Cyp19a1b) is a brain-specific enzyme that converts testosterone to estrogen and is highly upregulated in response to estrogen receptor activation localized to radial glial cells. During embryonic zebrafish development, there is a small window of time denoted by an increase in neurogenesis and estrogen receptor activity. Previous studies have demonstrated that a low dose BPA exposure (0.1µM) during this window causes hyperlocomotion in larval zebrafish, yet no further explanation for this behavior change has been described. The purpose of this study was to …

Nanoparticle Toxicity And Molecular Mechanisms In Fish: A Case Study With Silver Nanoparticles, Jiejun Gao

Open Access Dissertations

Nanoparticles (NPs) are widely used in a myriad of commercial and industrial products making their entry to the environment a likely event. NPs have unique physical-chemical properties that result from their small size and high surface area to volume ratio, making them highly reactive and potentially toxic. In Chapter 1, we summarize the effects and mechanisms of metal-based NPs on the vascular system. In vitro studies have shown that NPs are anti-angiogenic because they cause inflammation, oxidative stress, and apoptosis of endothelial cells resulting in increased permeability and decreased proliferation and migration. Whole animal studies examining the effects of NPs …

Quantifying The Toxicity Of 1-Methylnaphthalene To The Shallow-Water Coral, Porites Divaricata, For Use In The Target Lipid Model, Nicholas Turner

HCNSO Student Theses and Dissertations

The proximity of coral reefs to coastal urban areas and shipping lanes predisposes corals to petroleum pollution from multiple sources. Previous research has evaluated petroleum toxicity to coral using a variety of methodologies, including monitoring effects of acute and chronic spills, in situ exposures, and ex situ exposures with both adult and larval stage corals. Variability in toxicant, bioassay conditions, species and other methodological disparities among studies prevents comprehensive conclusions regarding the toxicity of hydrocarbons to corals. This research evaluated the 48-hour toxicity of 1-methylnaphthalene to Porites divaricata using a continuous-flow passive dosing system. The range-finding exposure evaluated the dosing …

Novel Approaches For Assessment Of Copper Toxicity: Fast Scan Cyclic Voltammetry And Optical Bioassays, Annette R. Tremonti

Wayne State University Dissertations

Anthropogenic activities negatively impact fresh water ecosystems through toxic contaminants that are released into the environment. Copper (Cu) is a water contaminant that is fundamentally persistent once introduced into the environment that has the potential for bioaccumulation. Although Cu toxicity has been studied for decades, there is still a continuing problem with new sources and pathways. New approaches are needed to understand distribution and transport of Cu and its potential for complex biological impacts beyond the simple assessment of lethality. Several novel approaches were used in this research project to advance our understanding of Cu toxicity, including fast scan cyclic …

Nickel And Copper Mixture Toxicity To Daphnia In Soft Water, Prachi Deshpande

Theses and Dissertations (Comprehensive)

Industrially important metals, such as Cu and Ni, sometimes are present at elevated concentrations in lakes, including those in the Sudbury, ON region. Although they are essential metals, their divalent-cation state (Cu²⁺ and Ni²⁺) can be toxic at high concentrations in the water. The free-ion toxicity of each of these metals has been studied in isolation, but rarely as a mixture. The economic importance of Cu²⁺ and Ni²⁺ makes them essential to study in the context of mixture toxicity. The objectives were to: (1) determine Cu and Ni mixture toxicity to Daphnia through acute LC50 …

Do Toxicity Modifying Factors Influence Acute Or Chronic Toxicity Of Thulium To Hyalella Azteca?, Alexandria H. Loveridge

Theses and Dissertations (Comprehensive)

The industrial demand for rare earth elements (REEs) is growing and as a result, environmental exposure is a concern. Very little is understood about the toxicity of REEs in aquatic environments. The objective of this research is to evaluate the acute and chronic toxicity of Tm and to also understand the toxicity modifying influence of dissolved organic matter (DOM) and cationic competition (Ca2+, Mg2+ and Na+). Furthermore, the aim of this study was to determine linkages between Tm bioaccumulation, growth and survival during chronic exposures. Standard methods (Environment Canada) were followed for both 96h acute and 14d chronic tests, in …

Nanoceria Exposure To Kidney Beans (Phaseolus Vulgaris): Implications On Plant Physiology, Nutrition And Their Transfer To Next Trophic Level, Sanghamitra Majumdar

Open Access Theses & Dissertations

Previous studies investigating the effects of cerium oxide nanoparticles (nanoceria, nCeO2) on plants have primarily focused on the physiological and biochemical changes at early growth stages. Comprehensive information on the effects of nCeO2 through the entire life cycle of plants and the nutritional quality of the edible tissues is limited. No studies have been reported on the interactions between nCeO2 and common beans (Phaseolus vulgaris). Common beans are leguminous crops, which are societally important due to their nutritional benefits. The beans are rich in proteins and essential nutrients like folate, iron, zinc, molybdenum and magnesium, and are consumed worldwide. This …

Carbon Nanomaterials In Freshwater Ecosystems: An Chronic, Multi-Generational, And Genomic Assessment Of Toxicity To Daphnia Magna, Devrah Anne Arndt

Theses and Dissertations

Carbon nanomaterials are synthesized with a variety of core structures and surface chemistries to make them more biocompatible for application in different industries, but variation in core structure and functionalization can change the toxicity of carbon nanomaterials to organisms. In addition, current literature is dominated by data from acute toxicity assays, but meta-data is necessary to improve our understanding of nanomaterial toxicity. This project identifies specific core structures and surface chemistries that make carbon nanomaterials more and less toxic using chronic toxicity assays and multi-generational assays to generate a dataset on the sub-lethal impacts of nanomaterials to Daphnia magna. In …

The Effects Of Sodium Lauryl Sulfate On The Abundance Of Producers And Grazers In Aquatic Communities Using Freshwater Microcosms, Stephanie R. Shipley

Honors College Theses

With increases in environmental awareness, industry has responded with products that reduce negative impacts on aquatic ecosystems. Sodium lauryl sulfate (SLS), a rapidly degrading chemical commonly found in cleaners labeled as ‘environmentally friendly,’ has been shown to have low toxicity in single species toxicity tests. However, that organisms have different sensitivities to SLS suggests a need for measuring effects at the community level. We exposed communities of microalgae (Chlorella sp.) and invertebrate grazers (a benthic snail, Elimia sp. and pelagic microcrustacean Daphnia magna) to 0, 0.5 or 1.5 mgL^-1 SLS. Water quality and invertebrate abundance were measured …

Bioaccumulation And Neuroinflammation Of Gold Nanoparticles In The Central Nervous System, Fahimeh Fallahi

Browse all Theses and Dissertations

Gold nanoparticles (GNPs) possess unique physicochemical properties that may facilitate entry into the central nervous system (CNS) where they may act therapeutically. There is little information on biodistribution or inflammatory effects of GNPs in specific brain regions. Brain Localization and neuroinflammatory response to citrate-capped spherical GNP (10 nm) was determined 24 hours after intravenous (IV) injection in male C57Bl mice. A known inflammogen, lipopolysaccharide (LPS, 2 mg kg-1, SC), was tested as a positive control supplement. Aggregation of GNPs was measured using various Phosphate-Buffered Saline (PBS) concentrations (10, 1, 0.1, 0.01 X) to determine the optimal buffer concentration to maintain …

The Chronic Toxicity Of Titanium Dioxide Nanoparticles To The Freshwater Amphipod Hyalella Azteca, Gurkirpal S. Malhi

Theses and Dissertations (Comprehensive)

There has been an increased use of metal-oxide nanoparticles in both commercial and consumer products. The use of these products and waste generated during manufacture may ultimately be released into the aquatic environment and the potential for these contaminants to cause impacts must be assessed. This study examines the effect of titanium dioxide (TiO₂) nanoparticles (NPs) on Hyalella azteca. Chronic toxicity exposures were conducted in 400mL of spiked test solution and contained 20 neonates. Samples collected for characterization of Ti in TiO₂ NP exposure solutions were digested using ammonium persulfate as an oxidizing agent and dissolved …

Evaluating Acute Toxicity Of Cadmium To Chironomid Using Hemoglobin As A Molecular Biomarker, Jun Taek Oh

Seton Hall University Dissertations and Theses (ETDs)

Effects of cadmium (Cd), a heavy metal contaminant, on hemoglobin were investigated in aquatic midge fly larvae of the Family, Chironomidae. In this study, chironomid populations from one polluted site, Kearny Marsh, New Jersey, two reference sites, North East Creek, and Bass Harbor, ME, and a laboratory population were taxonomically identified and tested for their sensitivity to Cd. Heavy metals in tissue, water and sediment were analyzed using Atomic Absorption Spectroscopy. Water quality at each site was assessed by measuring pH, dissolved oxygen (DO), oxidation-reduction potential ( eH), salinity and temperature. Hemoglobin proteins in individual larvae were easily detected using …

Embryo And Gamete Development Upon Exposure To Cca Components: Cro3, Cuo, And As2o5, Nerbana Talaat-Elsebaei Mahmoud

Theses and Dissertations in Biomedical Sciences

Production of functional gametes and healthy embryos is essential for proliferation of all vertebrates, especially humans. Many compounds have toxic effects on developing gametes and embryos among which are chromium trioxide (CrO₃), cupric oxide (CuO) and arsenic pentaoxide (As₂O₅) as a mixture (CCA) or individually. Controversy surrounding the safety of CCA-treated wood centers primarily on the toxicity of its components and the potential for these metals to be released from the wood.

The aim of this research is to test the hypothesis that CCA components have deleterious effects on embryo development, oocyte maturation and …

Effects Of Ethanol On The Toxicity And Metabolism Of Acetonitrile And Acrylonitrile, Nancy Ochoa-Garza

Theses and Dissertations - UTB/UTPA

This study examined the effects of ethanol on the toxicities and metabolism of two aliphatic nitriles: acetonitrile and acrylonitrile (one unsaturated and one saturated aliphatic nitrile, respectively) in male Sprague-Dawley rats at four different time intervals. Toxicity signs were apparent in all animals given the nitrile dosage, but those treated with ethanol dosages showed signs of toxicity earlier than those treated with glucose dosages. Both of the nitrites were metabolized to cyanide and thiocyanate. The concentration levels of each metabolite was apparent at 2 and 3 g/kg ethanol dosage for acetonitrile and 3 and 4.5 g/kg ethanol dosage for acrylonitrile …

In Vitro Assessment Of The Toxicity Of Cocaine And Its Metabolites In The Human Umbilical Artery, Tessa L. Long

Electronic Theses and Dissertations

An in vitro model was used to assess the effect of cocaine and its metabolites on the umbilical artery. Objectives were to pharmacologically confirm the presence of adrenergic innervation using tyramine, evaluate the ability of cocaine, benzoylecgonine, norcocaine and cocaethylene to potentiate vasoconstriction by serotonin and norepinephrine, examine the ability of ketanserin to block the enhanced vasoconstriction produced by cocaine, and determine displacement of 3 H-ketanserin by serotonin, norepinephrine, tyramine and mianserin. The vasoconstrictive effect of tyramine (100 μM) was enhanced in the presence of cocaine by 257%. Vasoconstrictive effects of serotonin and norepinephrine were significantly enhanced by cocaine by …

Metabolic Inhibition Of A Toluene-Enriched Microbial Population Due To Lead (Pb2+): Verification Of A Free Metal Ion Toxicity Model, Patrick J. S. Marbas

Theses and Dissertations

A dissolved oxygen probe and an ion specific electrode were used to study the lead-induced metabolic inhibition in a toluene-enriched microbial population. Predicted toxicity values were compared to the actual toxicity responses using a free metal ion toxicity model (TM) which linked metabolic inhibition with lead activity. Experimentally derived values for the model parameters (lead activity and a lead distribution coefficient) were used in the TM. It was postulated that cellular metabolism is disrupted by the conformational changes to the cell's plasma membrane produced by lead ion adsorption. The predicted toxicity values were higher than the actual toxicity response. This …