Life Sciences Commons^™

Inhibition Of Rad18 By Arsenic, Lindsay B. Volk

Biomedical Sciences ETDs

Arsenite exposure leads to the retention of UV-induced DNA damage, thus burdening translesion synthesis (TLS). Rad18 is an essential factor in initiating TLS through PCNA monoubiquitination and is implicated in homologous recombination. It contains two functionally and structurally distinct zinc fingers that are potential targets for arsenite binding. Results from this study reveal arsenite binding to both zinc fingers of Rad18 and a corresponding loss of domain function. Importantly, arsenite inhibited Rad18 RING-dependent PCNA monoubiquitination and polymerase eta recruitment to DNA damage. Further analysis demonstrated multiple effects of arsenite, including the reduction in the nuclear localization and UV-induced chromatin recruitment …

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) …

Role Of Plasma Membrane Intrinsic Proteins (Pips) Subfamily And Sulfur Nanoparticle Interactions In Metalloids Transport And Tolerance/Sensitivity In Rice, Ahmed Gm Ali

Doctoral Dissertations

Plasma membrane intrinsic proteins (PIPs) are major intrinsic proteins (MIPs) with the ability to permeate water and small uncharged solutes as well as metalloids including arsenic (As), through the cell membranes. Arsenic is a highly toxic element that occurs naturally in the earth's crust or from anthropogenic activities with a severe poisonous effect on most living organisms. Rice, as the daily staple food for more than half of the world population, accumulates higher As contents than any other economic crop due to its growing conditions in flooded paddy fields. Members from the NOD26-like intrinsic proteins (NIP) subfamily of MIP were …

Exploring The Response To Arsenic Using Trna Modification Detection, Writer Mediated Protection And Codon Usage Analytics, Anwesha Sarkar

Legacy Theses & Dissertations (2009 - 2024)

Transfer ribonucleic acid (tRNA) is a non-coding RNA which interacts with the messenger RNA (mRNA) to facilitate protein synthesis. tRNA is also one of the most heavily modified RNAs with the collection of modifications, termed as the tRNA epitranscriptome, ranging from simple methylation to complex hypermodification catalyzed by RNA epitranscriptomic writers. Detecting tRNA modifications is an evolving field and the state-of-the-art technologies that include next generation sequencing and mass spectrometry of intact and derivatized RNAs is described in the chapter one. Liquid chromatography coupled with mass spectrometry has previously been used to show that arsenic promotes increases in the levels …

Removal Of Arsenic (Iii) And Arsenic (V) From Aqueous Solution Via Common Sunflower Helianthus Annuus By Phytoremediation, Irving A. Vazquez Hurtado

Theses and Dissertations

Phytoremediation provides a cost-effective, non-invasive technique to remove contaminants from the soil and groundwater. Sunflowers are fast growing and have a showed effective at removing various pollutants from soil, including lead and other heavy metals. Health issues related to arsenic are mainly attributed to exposure of arsenite, whereas arsenate is much less toxic. The common sunflower Helianthus annuus was the species used to remove both arsenic (III) and As(V) ions from hydroponics solutions. In the present study sunflower seeds were germinated for a week, placed under the sun for a day and subsequently placed in a nutrient solution to aid …

The Effect Of Acute And Chronic Arsenic Exposure On Malignant Transformation Of The Human Bronchial Epithelial Cell (Beas-2b), Bandar Almutairy

Wayne State University Dissertations

Arsenic (As3+), a metalloid abundant in the environment, is classified as a group I carcinogen associated with several common human cancers, including cancers in the lung, skin, bladder, liver, and prostate (Wei, Zhang & Tao, 2019b). The mechanisms of As3+-induced carcinogenesis had been extensively studied, and different mechanisms might be involved in various types of cancer (Wei, Zhang & Tao, 2019b). Recent studies showed that exposure to a high dose of arsenic is able to induce lung cancer. Moreover, arsenic activates oncogenic signaling pathways such as MAPKs, EGFR/RAS/RAF, PI3K/AKT, and JNK/STAT3 pathways as well as epigenetic alterations such as miRNAs …

The Impacts Of Embryonic Arsenic Exposure Of Fundulus Heteroclitus, Torey Bowser

Electronic Theses and Dissertations

Arsenic is a toxic metalloid that exceeds safe drinking water standards in groundwater in many locations worldwide. Arsenic exposure in fish has been linked to destruction of gill tissues, impairment of growth, decreased muscle mass, memory impairment, increased aggression, and avoidance behaviors. We examined the behavior of mummichogs (Fundulus heteroclitus) following arsenic exposure during development in two studies. Embryos were collected from fish from three reference sites: Scorton Creek (SC), Massachusetts, Wells Harbor (WE), Maine, and Block Island (BLOC), Rhode Island and two contaminated sites: Callahan Mine (CM), Brooksville, Maine, and New Bedford Harbor (NBH), Massachusetts. Embryos were …

Assessing The Role Of Chronic Arsenite Exposure In Disrupting The Egfr Signaling Axis., Christine Kim

Electronic Theses and Dissertations

Chronic arsenic exposure is a risk factor for the development of pulmonary diseases, including lung cancer, but the exact mechanism is not yet fully understood. Many previous studies have relied on acute arsenic exposure (i.e. 1-10 uM arsenic for 24 hours) to study arsenic toxicological effects. However, acute exposure does not reflect the levels or duration of arsenic associated with environmental exposure, or drinking of contaminated well water. This dissertation differentiates the effects of acute versus chronic arsenic exposures on the EGFR signaling axis and suggests possible mechanisms for chronic arsenic-induced pulmonary diseases. The EGFR is a receptor tyrosine kinase …

Disadvantaged Vs. Non-Disadvantaged Drinking Water: San Joaquin County Groundwater Variable By Contaminant, Megan Brooks

Master's Projects and Capstones

This research explored drinking water wells that have detectable levels of arsenic and nitrate in disadvantaged vs. non-disadvantaged communities in San Joaquin County. The CalEnviroScreen 3.0 program and Groundwater Ambient Monitoring Program (GAMA) are used to measure disadvantaged communities and water quality data respectively. The CalEnviroScreen 3.0 scoring formula is used to calculate which census tracts are disadvantaged based on indices that measure pollution burden and population characteristics. The scoring is then combined with a census tract layer using Geographic Information Systems (GIS) technology. The disadvantaged community data are overlaid with GAMA groundwater well data to locate which communities are …

Diverse Community Of Arsenic Resistant Bacteria Display Arsenate Reducing Capabilities, Stephanie Maeda

Undergraduate Honors Theses

Naturally found in soil and water environments arsenic is toxic to many organisms, carcinogenic to humans, and poses a significant public health risk. Yet communities of bacteria found thriving in arsenic ridden environments have evolved mechanisms to tolerate and exploit both oxidation states of this heavy metal (arsenite and arsenate). As the site of an old arsenic mine, Black Mountain Open Space Park in San Diego, California has yielded concentrations of arsenic in the soil between 111-14,800 ppm. Exceeding average arsenic soil concentrations and levels considered safe in the environment by the World Health Organization, we sought to characterize the …

Sunflower Seedlings Fail To Remove Uranium Pollution In The Navajo Nation: Participatory Science As A Path To Build Community And Address Environmental Injustice, Zak R. Webber

Undergraduate Honors Theses

Mid-20th century mining on Naabeehó Bináhásdzo (Navajo Nation) polluted groundwater with high concentrations of uranium and arsenic. The Navajo Nation and other rural residents of this region use groundwater for drinking, livestock, and irrigation. However, many individuals and communities must purchase and transport treated water from locations that are often hours away. Sunflowers have been shown to preferentially take up heavy metals, including uranium and arsenic, potentially representing a tool to improve water quality through on-site, low-cost phytoremediation. We carried out a collaborative research project with a high school class on the Navajo Nation in 2018 and 2019. The students …

The Impacts Of Gold Mining On Vegetation And Mycorrhizal Colonization In Northern Canada, Sarah Mediouni

Theses and Dissertations (Comprehensive)

Gold mining is an important part of economic development in Northern Canada. A large portion of the gold that is found in the North is contained within arsenopyrite ores, therefore, arsenic contamination is of special concern. Little is known regarding the impacts of arsenic on plants and mycorrhizae in Northern Ecosystems. Arsenic has been shown to negatively impact plant growth and seed germination in some temperate species, while others are tolerant and can accumulate arsenic concentrations over 1000 mg/kg. In temperate regions, arbuscular mycorrhiza can accelerate the remediation process in gold mines by supporting plant growth in poor soil conditions …

Effect Of Arsenic Exposure On Early Eye Development In Zebrafish (Danio Rerio), Remy S. Babich

Electronic Theses and Dissertations

Arsenic is a metalloid that contaminates drinking water supplies worldwide. Due to concerns for human health, the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA) have established a safe level in drinking water of ≤ 10 ppb. Arsenic has been shown to have carcinogenic effects in humans at high and low doses. Chronic exposure may result in dermal conditions such as hyperkeratosis and hyperpigmentation. Recently, arsenic exposure has also been linked to lower IQ values in children. The effect of arsenic on neurogenesis, specifically eye development, has not been widely explored. This study aimed to examine the …

Molecular Mechanisms Underlying Toxicant Effects On Mast Cell Signaling And Mitochondria, Juyoung Katherine Shim

Electronic Theses and Dissertations

Mast cells contribute to numerous physiological processes and diseases including immunological and neurological roles. Mast cells degranulate, releasing potent mediators, following signaling transduction initiated by receptor crosslinking. Previously, we showed that the environmental toxicant arsenic and the antibacterial agent triclosan inhibit mast cell degranulation; thus, we have investigated the mechanisms underlying their inhibitory action. We have discovered that arsenic targets early steps in the mast cell signaling pathway: it inhibits phosphorylation of early tyrosine kinase Syk and of Syk’s direct substrate PI3K. Arsenic’s tyrosine phosphorylation inhibition causes inhibition of calcium influx into the cytosol, a key event necessary for degranulation. …

A Model To Study The Effects Of Whole Life Chronic Exposure To Arsenic Or Cadmium On The Development Of Adult Metabolic Syndrome : Initial Characterization Of Hepatic Changes., Jamie L. Young

Electronic Theses and Dissertations

Metabolic syndrome (MetS) is a group of diseases affecting < 30% of adults. Although obesity is a major risk for the development of MetS, it does not account for all cases, suggesting contribution of other risk factors. We hypothesized that early life exposure to arsenic (As) or cadmium (Cd) may represent such a risk. The purpose of this study was to characterize a model to discern the effects of early life exposures to Cd and As on high fat diet (HFD)-induced MetS. Adult C57BL/6J mice were exposed to control or metals containing drinking water. Pregnant dams and offspring were continuously exposed to the same toxicants as their parents. At weaning, offspring were fed LFD or HFD and sacrificed 10 or 24 weeks later. Metal exposure caused time- and sex-dependent alterations in HFD-induced variables of liver damage. The initial results suggest that these toxicants enhanced obesity-induced liver injury.

Expression Profiling Of Non-Coding Rna By Environmental Interactions In Innate Immunity, Jacob R. Longfellow

Electronic Theses and Dissertations

Cystic fibrosis (CF) is a genetic disorder that affects 30,000 people in the United States and currently has no cure. Although CF affects all of the body’s systems, it is largely characterized as a lung disease. CF is caused by a mutation in both copies of the gene for cystic fibrosis transmembrane conductance regulator (CFTR). A mutation in the CFTR gene leads to improper movement of chloride ions and water into the airways, which dysregulates the airway surface liquid volume and composition. Individuals with CF are prone to lung infections due to inefficient bacterial clearance and by the age of …

Metalation And Structural Properties Of Apo-Metallothioneins, Gordon W. Irvine

Electronic Thesis and Dissertation Repository

Metals are required by a quarter of all proteins to achieve their biological function, whether in an active site involved in catalytic chemistry or in a structural capacity. Metals are tightly regulated at the cellular level due to their propensity to cause unwanted side reactions and to be scavenged for use by pathogens. One of the proteins involved in this regulation of metal homeostasis is metallothionein (MT) which is a small, cysteine rich protein primarily involved in the regulation of zinc and copper homeostasis and heavy metal detoxification. MT is unique in its high cysteine content (~30% of the residues), …

Mechanisms Of Thymic Toxicity Induced By Environmentally Relevant Concentrations Of Arsenic, Huan Xu

Biomedical Sciences ETDs

Arsenic, a ubiquitous environmental contaminant, is known to cause immunotoxicity. However, the mechanisms of arsenic induced immunotoxicity are still not clear. Arsenite (As⁺³), the trivalent inorganic form of arsenic, was found to increase DNA damage and inhibit PARP activity in thymus cells at 50 nM in vitro. Oxidative stress and double strand breaks (DSBs) formation occurred in thymus cells exposed to As⁺³ at 500 nM. The genotoxicity was found to be related to As⁺³ exporter expressions and reversed by zinc supplement. IL-7 signaling, the critical cytokine signal for the early DN thymic T cell proliferation, …

An Assessment Of How Plant And Mycorrhizal Communities Have Been Affected Along A Mine-Impacted Watershed In The Northwest Territories, Kevin Maccoll

Theses and Dissertations (Comprehensive)

Giant Mine is an inactive gold mine located nine kilometers north of Yellowknife, Northwest Territories. Giant Mine has been the source of arsenic trioxide for the Baker Creek watershed since it opened over 60 years ago. Although arsenic levels in the creek are above the limits considered to be biologically relevant, there is no concrete evidence that plants and mycorrhizae have actually been affected. This study provides an initial assessment of the impacts mining activity at Giant Mine has had on plants and mycorrhizae in the Baker Creek watershed. Nine sites were sampled around Giant Mine: five sites downstream from …

Arsenic Inhibits P19 Stem Cell Differentiation By Altering Microrna Expression And Repressing The Sonic Hedgehog Signaling Pathway, Jui Tung Liu

All Dissertations

Arsenic is a naturally-occurring toxicant that exists in bedrock and can be leached into ground water. Humans can be exposed to arsenic via contaminated drinking water, fruit, rice or crops. Epidemiological studies have shown that arsenic is a developmental toxicant, and in utero exposure reduces IQ scores, verbal learning ability, decreases long term memory, and increases the likelihood of dying from a neurological disorder. Arsenic can also reduce birth weight, weight gain, and muscle function after an in utero exposure. Although the mechanism behind these physiological changes is not known, in vitro studies have shown that arsenic can reduce muscle …

An Epidemiological Study Of Campylobacter Populations Reveals A Selective Pressure By Roxarsone, Sean Jeffery Pendleton

Doctoral Dissertations

Whole genome sequencing (WGS) is the most discriminatory of typing methods and can provide additional information including virulence, antigen targets for vaccine development, and antimicrobial resistance profiles. The first part of this study aimed to determine the application of WGS as a genotyping method for Campylobacter by comparing WGS to two commonly used genotyping methods, Pulsed-field gel electrophoresis (PFGE) and flaA typing. Five Campylobacter strains isolated from conventional and organic poultry, and five additional isolates with published genomes were compared using the three methods. A total of 8 PFGE patterns and 8 flaA alleles were identified from the 10 strains. …

Arsenic Targets Neural Plate Border Specifier Cells In P19 Cells, Christopher Mccoy

All Theses

Epidemiological studies have shown that arsenic exposure during early embryogenesis can cause reduced weight gain and neurological deficits later on in life. In addition, in vitro and in vivo studies have indicated that arsenic suppresses neurogenesis and myogenesis. The exact mechanism of how arsenic causes these undesired developmental outcomes is poorly understood, however both skeletal muscle and sensory neuron development require the Wnt/β-catenin signaling pathway to initiate the specific differentiation of precursor cells. We were interested in determining the target cell population of arsenic and its metabolites. Arsenic's metabolites were of interest because they have been shown to be more …

Studies In The Atomic Spectrometric Determination And Speciation Of Arsenic In Environmental Samples, Nan Wang

Doctoral Dissertations

The application of work described in this dissertation, the determination of total and arsenic species in water and rice samples, is of considerable societal importance as large numbers of the citizens of many countries around the world are exposed to potentially harmful concentrations of these carcinogenic compounds by daily consumption. The field of analytical chemistry is crucial to support the operation of any treatment to decrease arsenic concentrations as well as any regulations and legislation regarding arsenic in food and the environment. The current goals of research in trace arsenic measurements and speciation are to increase knowledge of the subject …

Sulfate Reducing Communities In Aquifer Systems Can Be Reliably Stimulated By Addition Of Complex Nutrients, Matthew Bryan Scholz

Doctoral Dissertations

The disseration presented below is the summation of research into the potential roles of microbial communities associated with aquifers of Bangladesh contaminated with naturally occuring arsenic. These investigations also included experimental microcosm experiments to assess the role of nutrients supplementation of complex carbon sources (molasses), and inorganic sulfate (MgSO4), on both the solubility of arsenic to determine the feasibility of this method for the goal of performing in situ bioremediation. Community structure and functional gene profiling was performed on all samples, as well as detection of community shifts following amendments predicted to encourage the growth of sulfate reducting microorganisms (SRM). …

Arsenic Affects Muscle Development And Structure In Fundulus Heteroclitus, Angela D'Amico

All Theses

Arsenic is a naturally occurring metalloid that can enter rivers and ground water. Epidemiological studies have correlated arsenic exposure with adverse developmental outcomes such as low birth weight, delays in the use of musculature, and altered locomotor activity. Previously in our lab, embryonically exposed killifish (Fundulus heteroclitus) were found to have changes in muscle development. Microarray analysis showed several genes involved in muscle development and formation altered and histological analysis showed an increase in small muscle fiber size. In this study, killifish were used to help understand if changes in muscle formation and fiber density after embryonic exposure persist, are …

Arsenic Contamination In Groundwater In Vietnam: An Overview And Analysis Of The Historical, Cultural, Economic, And Political Parameters In The Success Of Various Mitigation Options, Thuy M. Ly

Pomona Senior Theses

Although arsenic is naturally present in the environment, 99% of human exposure to arsenic is through ingestion. Throughout history, arsenic is known as “the king of poisons”; it is mutagenic, carcinogenic, and teratogenic. Even in smaller concentrations, it accumulates in the body and takes decades before any physical symptoms of arsenic poisoning shows. According to the World Health Organization (WHO), the safe concentration of arsenic in drinking water is 10 µg/L. However, this limit is often times ignored until it is decades too late and people begin showing symptoms of having been poisoned.

This is the current situation for Vietnam, …

Occupational Exposure And Risk Of Skin Cancer In A Multinational European Study, Simona Surdu

Legacy Theses & Dissertations (2009 - 2024)

Non-melanoma skin cancers (NMSC) comprise more than one third of all cancers, and are increasing worldwide. The most common NMSC are Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC). Studies on humans and animals suggest that sunlight and arsenic play important roles in the pathogenesis of these skin malignancies. However, the number of epidemiological studies focusing on NMSC in workers exposed to ultraviolet (UV) radiation or airborne arsenic is limited, and the findings are contradictory.

Chromium, Copper, And Arsenic Concentration And Speciation In Soil Adjacent To Chromated Copper Arsenate (Cca) Treated Lumber Along A Topohydrosequence, Donald Roy Schwer Iii

University of Kentucky Master's Theses

Arsenic (As), Chromium (Cr), and Copper (Cu) are ubiquitous in soils as a result of anthropogenic and geogenic processes. The fate of As, Cr, and Cu in the environment is largely governed by their speciation, which is influenced by soil physiochemical properties. This study investigated the influence of soil physiochemical properties and landscape position on As, Cr, and Cu concentration and speciation in soils adjacent to Chromated Copper Arsenate (CCA) treated lumber fence posts. Concentration gradients showed elevated total As and Cu adjacent to the three fence posts, which decreased with increasing distance from the posts. In addition, As and …

Characterization Of Arsd: An Arsenic Chaperone For The Arsab As(Iii)-Translocating Atpase, Jianbo Yang

Wayne State University Dissertations

Arsenic is a metalloid toxicant that is widely distributed throughout the earth's crust and causes a variety of health and environment problems. As an adaptation to arsenic-contaminated environments, organisms have developed resistance systems. In bacteria and archaea various ars operons encode ArsAB ATPases that pump the trivalent metalloids As(III) or Sb(III) out of cells. In these operons, an arsD gene is almost always adjacent to the arsA gene, suggesting a related function. ArsA is the catalytic subunit of the pump that hydrolyzes ATP in the presence of arsenite or antimonite. ArsB is a membrane protein which containing arsenite-conducting pathway. ArsA …

Arsenic Speciation Analysis Of Biological Fluids : A Study Of Liquid Chromatography Coupled To Analytical Atomic Spectrometric Instrumentation, Kanna Ito

Legacy Theses & Dissertations (2009 - 2024)

Arsenic exists as many different chemical forms including inorganic, methylated and dietary species. The toxicity of these species varies: some are highly toxic and can cause adverse health effects in many parts of the body; others are considered relatively non-toxic. Monitoring arsenic exposure is usually accomplished by its direct measurement in biological fluids. Urine is the specimen of choice for assessing arsenic exposure, because of its short biological half-life in blood. There have been very few studies of arsenic species in blood, yet such research can provide valuable information on arsenic distribution and its metabolism in the body.