Toxicology Commons^™

Environmental Mercury Alters Immune Pathways Linked To Autoimmune Risk In Mice Mirroring Humans, Maurgan Lee, Paul Stemmer, Randall Gill, Allen Rosenspire, Anil Aranha, Heather Gibson

Medical Student Research Symposium

Background and Purpose: Mercury is a pervasive environmental contaminant, and human epidemiologic studies have linked chronic low-level exposure to increased autoimmune disease-risk. Dysregulated lymphocyte activation and impaired signaling tolerance are central mechanisms in human autoimmunity. Protein phosphorylation governs lymphocyte differentiation and function, alterations in phosphoproteomic networks may represent a signature of immune disruption. This study evaluates how low dose mercury exposure modifies B and T cell abundance and intracellular signaling patterns in BALB/c and Diversity Outbred (DO) mice.

Methods: BALB/c and DO mice were exposed to low dose HgCl2 in their water for two weeks or provided standard water controls. …

Seafood, Mercury, And Human Health In Coastal South Carolina: Findings From A Community-Based Study, Russell Fielding, Julia Saltzman, Rylee-Jade Bean, Jenna Monroe, Theodore R. Them Ii

Honors College Faculty Publications

Mercury (Hg), an environmental pollutant, can harm human health. Seafood consumption is a major way that people are exposed to Hg and the analysis of human hair is a standard method to measure Hg exposure. This community-based study identified demographic and dietary factors associated with elevated Hg concentrations and health outcomes of individuals with elevated Hg concentrations throughout two coastal South Carolina (SC) counties. We collected hair samples (n = 85) at local barbershops and salons; participants completed an online survey with questions on demographics, diet, and health histories; and we analyzed hair samples using a DMA-80. Between 4.9–8.4% of …

Bioaccumulation Of Polychlorinated Biphenyl Compounds And Mercury In A Mining Impacted Aquatic Ecosystem, Michelle Bollini

Dissertations, Master's Theses and Master's Reports

The Keweenaw area continues to be influenced by the century of copper mining that ended nearly 50 years ago. This project is focused on Torch Lake, an aquatic ecosystem that has been heavily impacted by mining waste disposal. The watershed has been impaired by mine discharge and tailings, smelter and smokestack plumes, and poor waste disposal practices. The lake is listed as a Great Lakes Area of Concern with beneficial use impairments of restrictions on fish consumption and a degraded benthic community. Polychlorinated biphenyl compounds (PCBs) and methylmercury (MeHg) are persistent, bioaccumulative, and toxic substances (PBTs). These contaminants pose threats …

Avian Haemosporidian Blood Parasite Diversity, Prevalence, And Distribution In Michigan’S Western Upper Peninsula, Maria M. Ferrer

Dissertations, Master's Theses and Master's Reports

Avian haemosporidian parasites, known as avian malaria (phylum Apicomplexa) can diminish an individual bird’s fitness by causing parasitemia, anemia, and reduced survival. Climate change is predicted to increase the spread of malarial parasites into more northerly latitudes where little is known about community compositions of these parasites. I assessed the prevalence and diversity of haemosporidian parasites in the first-ever community-level sampling of malaria in songbirds across the western Upper Peninsula of Michigan. In total, 179 blood samples were collected from birds representing 17 species, at five locations in the Upper Peninsula, including a mature forest, an early successional forest, and …

Effects Of Mercury On The Dopamine Transporter Cell Surface Expression In Pc12 Cells, Christina Hui

Student Theses

Environmental factors, such as heavy metal exposures, have been suggested to have an impact not only on neurodegenerative disease, such as Parkinson’s disease, but also on psychostimulants abuse and their toxicity. In this study, two questions were addressed: 1) effects of mercuric chloride on parkinsonian toxicant 1-methyl-4-phenylpyridinium (MPP⁺) induced cytotoxicity and 2) effects of mercuric chloride on cell surface dopamine transporter. Pheochromocytorma cells (PC12) were treated with various concentrations of mercuric chloride (0.02~2.0 ppm) for 4 hours with and without 0.1 mM MPP⁺. Significant potentiation of toxicity was observed when there was co-treatment with 0.5 ppm …

Mercury Concentrations In Snowy Plovers And Sediments Of Their Breeding Environments In The Southern Great Plains, Laura Duffie

Electronic Theses and Dissertations

Western snowy plovers (Charadrius nivosus) are philopatric shorebirds sporadically distributed during the breeding season at saline lake and alkali flat breeding environments of the Southern Great Plains (SGP) of Oklahoma, New Mexico, and Texas. The major conservation threat to interior snowy plovers breeding on the SGP derives from anthropogenic modification of breeding environments. The SGP is one of the most intensively cultivated regions in the world, and excessive groundwater mining and resulting deterioration of artesian spring flows reduces site quantity and quality critical for regional successful nesting. Most saline lakes now primarily receive freshwater inputs via irregular precipitation …

An Ecotoxicological Survey Of Tributaries Of The Selenge River, Mongolia, August 2010, Viktor T. Komov, Ch. Javzan, William G. Brumbaugh

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The biodiversity of the Selenga river basin and the receiving waters of the lake Baikal, are among the greatest in the world with over 1,700 known endemic species of plants and animals. Mining activities along the Selenga river and its tributaries pose a major threat of chemical contamination, potentially reducing habitat quality and suitability for aquatic species. Moreover, the Selenga river serves as a major water source for the lake Baikal. Little information exists on the chemical contaminant concentrations in the Selenga river basin. Thus, the objectives of our study were to evaluate the concentrations of metals in soil, sediment, …

Derivation Of Screening Benchmarks For Dietary Methylmercury Exposure For The Common Loon (Gavia Immer): Rationale For Use In Ecological Risk Assessment, David C. Depew, Niladri Basu, Neil M. Burgess, Linda M. Campbell

University Faculty Publications and Creative Works

The current understanding of methylmercury (MeHg) toxicity to avian species has improved considerably in recent years and indicates that exposure to environmentally relevant concentrations of MeHg through the diet can adversely affect various aspects of avian health, reproduction, and survival. Because fish-eating birds are at particular risk for elevated MeHg exposure, the authors surveyed the available primary and secondary literature to summarize the effects of dietary MeHg on the common loon (Gavia immer) and to derive ecologically relevant toxic thresholds for dietary exposure to MeHg in fish prey. After considering the available data, the authors propose three screening benchmarks of …

Gene And Environment Interactions Modulate Immune System Influences On Social Behavior, Yubin Zhang

Legacy Theses & Dissertations (2009 - 2024)

Autism is a neurodevelopmental disorder with unknown etiology, affecting about 1 in 110 children in the US. Here, we show that developmental exposure to anti-brain Abs impaired mouse social behaviors. BTBR mice, a mouse strain with high serum anti-brain Abs and behaviors that resemble autism, have more activated splenic B cells, CD4+ T cells (Th1, Th2 and Th17 subsets), and CD4+ T cells with expression of Vb6 chains than B6 mice (the control H-2 identical strain). Elevated numbers of activated (CD25+) CD4+Vb6+ cells also were detected in thymic preparations. All of the immunological and behavioral parameters of BTBR mice were …

A Broad-Spectrum Mer Operon In A Multi-Drug Resistant Strain Of The Fish Pathogen, Aeromonas Salmonicida, Erin Parry

Honors Theses

Aeromonas salmonicida AS03, a potential fish pathogen, was isolated from Atlantic salmon, Salmo salar, in 2003. This strain was found to be resistant to ≥1000 mM HgCl2 and ≥32 mM phenylmercuric acetate as well as multiple antimicrobials. Mercury (Hg) and antibiotic resistance genes are often located on the same mobile genetic elements, so the genetic determinants of both resistances and the possibility of horizontal gene transfer were examined. Specific PCR primers were used to amplify and sequence distinctive regions of the mer operon. A. salmonicida AS03 was found to have a pDU1358-like broad-spectrum mer operon, containing merB as well as …

Pyoveridine Production By Pseudomonas Aeruginosa Exposed To Metals Or An Oxidative Stress Agent, Kim-Hien Thi Dao, Katherine E. Hamer, Christine L. Clark, Lawrence G. Harshman

School of Biological Sciences: Faculty Publications

Siderophores are low molecular mass compounds used by many microorganisms to scavenge dissolved iron, which is typically rare in environments. Pseudomonas aeruginosa (PAO1) was exposed to metals and methyl viologen in low-iron medium in order to monitor the abundance of a specific siderophore (pyoverdine) and monitor growth over time. In this study it was discovered that cadmium can stimulate pyoverdine abundance. Cadmium may interact with and sequester the Fur regulatory protein, which represses siderophore synthesis under conditions of iron sufficiency. Mercury did not stimulate pyoverdine production at concentrations that strongly inhibited bacterial growth, suggesting that pyoverdine production is not governed …

Biological Detoxification Of Mercury Contaminated Soil, Shiying Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined biological mercury removal from soil using mercury-resistant bacteria in soil microcosms. Mercuric chloride was used to artificially contaminate Kidman soil to mercury concentrations of 5 ppm and 10 ppm. Soil moisture content was maintained at three levels, 20%, 30% and 50%. Mercury resistant-bacteria were added to soil samples and the mercury removal rate was compared to control samples without added bacteria. Mercury removal rate was initially enhanced by the addition of bacteria. After 30 days, no difference was observed between samples and controls with initial mercury concentration of 5 ppm when soil moisture content was 20%. At …

Mercury, Dieldrin, Ddt, Dde, And Pcb Levels In Tissues From Fish And Wildlife In Utah, Fred A. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fish and wildlife were randomly sampled in Utah from pre-selected x areas and analyzed for levels of total mercury, dieldrin, DDT, and DDE. Levels were well within consumptive tolerance or guideline limits except for mercury levels of fish in Willard Bay Reservoir. PCB's were also identified in a large proportion of samples.

None of the chukars, 6 percent of the pheasants, 4 percent of the waterfowl, and none of the fish sampled, excluding Willard Bay Reservoir, were above the 0.5 ppm guideline level for mercury established by the Food and Drug Administration. Seventy-seven percent of the fish sampled from Willard …