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Much Needed Studies Of The Three Players Of Chagas Disease In Central America: Vertebrate Blood Meal Sources And Ecohealth, A New Vector Species Description, And Key Phylogenetic Analysis Of The Trypanosome Parasite., Raquel Asuncion Lima Cordon

Graduate College Dissertations and Theses

The protozoan parasite Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae) is the etiological agent of Chagas disease, reported by the World Health Organization (WHO) as responsible for over 10,000 deaths in 2015. Chagas disease is considered a Neglected Tropical Disease by the WHO, this designation highlights the challenges to overcoming the disease as it afflicts the most vulnerable populations, mainly the rural poor in Latin America. Understanding T. cruzi transmission dynamics is particularly difficult because it can be vectored by over 150 species of Triatominae insects, and all mammal species are potential hosts. Thus, results from one locale may not be generalizable to …

Structure Activity Relationship Studies Of An Anticryptosporidial Drug, Kirtika Chatri

Graduate College Dissertations and Theses

Cryptosporidium is an apicomplexan parasite responsible for waterborne outbreaks of diarrheal disease worldwide. There are two species of Cryptosporidium that are important enteric pathogens for humans. The disease, Cryptosporidiosis, is a major cause of childhood diarrhea and an important factor in childhood malnutrition and also a high rate of death (Sparks et al., 2015). It is also more frequent and severe in malnourished children under 3 years of age and immune-compromised individuals, such as AIDS and transplant patients. A common treatment which has greatly reduced diarrhea-associated mortality is oral rehydration therapy; however, enteric infections still persist (Guerrant, DeBoer, Moore, Scharf, …

Network And Cellular Effects Of The Mu Opioid Receptor In Cortical Interneurons, Adrian Dutkiewicz

Graduate College Dissertations and Theses

The µ opioid receptor (µOR) exerts a powerful excitatory effect in cortical circuits and cultured neurons by promoting glutamatergic activity after binding endogenous or exogenous opioids. While most research indicates that the receptor does this by decreasing activity or output of GABAergic interneurons that inhibit glutamate-releasing Pyramidal Neurons, other experiments suggest that the µOR directly upregulates excitatory Pyramidal Neurons instead. Thus, the cellular target of cortical opioid agonists remains unclear, and the µOR’s net excitatory mechanisms are not fully understood. Consequently, utilizing electrophysiology to detect µOR responses to the specific agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin (DAMGO) has yielded incomplete information on …

The Role Of Infralimbic Cortex In Switching Between An Instrumental Behavior’S Status As A Goal-Directed Action Or Habit, Matthew Broomer

Graduate College Dissertations and Theses

In instrumental learning, extensive training of a response typically generates a habit. The transition from goal-directed to habitual behavioral control is often considered unidirectional; however, recent evidence suggests this is not the case. Under certain conditions, goal-directed control may be restored to a behavior that was previously habitual. We identify the infralimbic cortex (IL) as a participant in this process and draw on both instrumental learning and fear extinction literatures to further our understanding of IL function.

Four experiments explored the role of IL in flexible behavior. Experiments 1a and 1b were instrumental learning experiments. Experiment 1a used a previously …

Analysis Of Intracellular Calcium Events In Hypothalamic Neurons, Samantha Kolowrat

Graduate College Dissertations and Theses

The paraventricular nucleus of the hypothalamus (PVN) plays a critical role in regulating the hypothalamic-pituitary-adrenal (HPA) axis, sympathetic activity, cardiovascular system and stress responses.1,2 This brain region is primarily controlled by GABA and glutamate inputs from the peri-PVN region.3 Two significant modulators of these GABA-glutamate systems are Angiotensin II (Ang II) and brain derived neurotrophic factor (BDNF). It has been postulated that BDNF and Ang II signaling rely on each other via cross-activation of their receptors and by activation of the non-selective cation channel, the transient receptor channel type C3 (TRPC3).This thesis aims to study changes in intracellular calcium levels …

The Role Of Bdnf-Mediated Neuroplasticity In Cardiovascular Regulation Within The Hypothalamus And Brainstem, Daniella Johanna Thorsdottir

Graduate College Dissertations and Theses

The paraventricular nucleus of the hypothalamus (PVN) is an important cardiovascular and autonomic regulatory center. Activation of PVN neurons projecting to the brainstem and spinal cord elevates sympathetic activity and blood pressure. Brain derived neurotrophic factor (BDNF) plays a key role in stress-induced cardiovascular responses within the PVN and is also known to be upregulated in the PVN in response to stress and hyperosmolality. PVN overexpression or acute injection of BDNF also elevates blood pressure chronically. However, the mechanism behind BDNF-mediated cardiovascular regulation is not fully understood. BDNF is known to modulate excitatory/inhibitory signaling by altering the expression and membrane …

Brain-Behavior Connections Underlying Emotion And Theory Of Mind In Autism Spectrum Disorder, Yu Han

Graduate College Dissertations and Theses

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder that af- fects nearly 1 in 54 children. Children with ASD struggle with social, communication, and behavioral challenges due to deficits in theory of mind (ToM). In addition, diag- nosis of ASD is complicated and there is an urgent need to identify ASD-associated biomarkers and features to help automate diagnostics and develop predictive ASD models. In this study, we conducted two experiments collecting behavioral and neu- roimaging data from 9 children with ASD and 19 neurotypical children (NT) between the age of 7 and 14 years.

The first experiment examined specific …

Investigating The Role Of Protein Kinase A In The Control Of Focal Adhesion And Traction Force Dynamics, Amanda Senatore

Graduate College Dissertations and Theses

Cellular adhesion to the extracellular environment is a critical component of physiological processes and its dysregulation drives pathological processes such as cancer metastasis. The input cells derive from their interaction with the extracellular matrix (ECM) is largely mediated through specialized organelles known as focal adhesions (FAs). FAs tether extracellular matrix-bound integrins to the contractile actin cytoskeleton and serve as attachment points which allow the cell to exert force on the extracellular environment via acto-myosin contractility. In addition to this structural role, FAs function as dynamic signaling hubs that respond to changes in force. Reversible phosphorylation plays a major role in …

The Effects Of Interneuron Progenitor Cell Transplantation On Network Dynamics In An Animal Model Of Mesial Temporal Lobe Epilepsy, Willie Curry

Graduate College Dissertations and Theses

Epilepsy is associated with a very high incidence of cognitive and behavioral comorbidities that are detrimental to overall quality of life. Current treatments for epilepsy,namely anticonvulsant pharmacological agents, generally increase the amount of inhibitory drive in order to counteract the hyperexcitability observed in the disorder. However, administration of these agents, while effective for 70% of epilepsy sufferers, leave a residual 30% of patients who don’t become seizure-free. The concomitant adverse side effects of anticonvulsants - these can paradoxically include increased cognitive "fog" or confusion, automatisms, and even increased number of seizures - are a great additional concern, as is the …

Examining Sex Differences In Habit Formation: Effects Of Methamphetamine Sensitization And Contributions Of Ovarian Hormones, Hannah Schoenberg Book

Graduate College Dissertations and Theses

In the early stages of instrumental learning, behavior is goal-directed and sensitive to changes in the value of the instrumental outcome. As learning progresses, an association forms between the response and stimuli within the learning environment, such that after sufficient repetition, responding is evoked automatically in the presence of these stimuli and is insensitive to changes in outcome value. The reflexive nature of these types of behaviors has led to their classification as instrumental habits. The emergence of habitual behavior is thought to involve parallel processes that are mediated by distinct neural substrates. Regions of the prefrontal cortex, amygdala, and …

Microevolution In Staphylococcus Aureus: Does Exposure To Sub-Lethal Levels Of Cinnamon Bark Oil Lead To Changes In Antimicrobial Susceptibility?, Heather Sandra Schuettner

Graduate College Dissertations and Theses

The emergence of antibiotic-resistant and multi-drug resistant bacteria presents a growing global health issue recognized by the World Health Organization and the Centers for Disease Control and Prevention. Infections caused by drug-resistant bacteria are associated with longer hospital stays, higher treatments costs, and increased mortality compared to infections caused by antibiotic-susceptible pathogens. The global increase in antibiotic resistance is driven in part by the misuse and overuse of antibiotics in healthcare and agriculture. Staphylococcus aureus can infect humans and animals, and strains that are resistant to one or more antibiotics are common. Many plant essential oils have antimicrobial properties. Essential …

Microevolution In Staphylococcus Aureus: Does Exposure To Sub-Lethal Levels Of Cinnamon Bark Oil Lead To Changes In Antimicrobial Susceptibility?, Heather Sandra Schuettner

Graduate College Dissertations and Theses

The emergence of antibiotic-resistant and multi-drug resistant bacteria presents a growing global health issue recognized by the World Health Organization and the Centers for Disease Control and Prevention. Infections caused by drug-resistant bacteria are associated with longer hospital stays, higher treatments costs, and increased mortality compared to infections caused by antibiotic-susceptible pathogens. The global increase in antibiotic resistance is driven in part by the misuse and overuse of antibiotics in healthcare and agriculture. Staphylococcus aureus can infect humans and animals, and strains that are resistant to one or more antibiotics are common. Many plant essential oils have antimicrobial properties. Essential …

Transcriptional Programming By Thyroid Hormone Receptor Beta Maintains Normal Cell Identity And Suppresses Tumor Growth, Noelle Elizabeth Gillis

Graduate College Dissertations and Theses

The overall incidence of thyroid cancer has more than tripled over the past several decades, as has aggressive disease and mortality. The direct relationship between thyroid disease, thyroid hormone levels, and development of thyroid cancer is incomplete. Recent meta-analyses have indicated a higher risk of thyroid cancer for patients with thyroid diseases that reflect an altered thyroid-pituitary signaling axis, which can have profound impacts on the physiology of the thyroid gland. These largely unanswered questions regarding altered thyroid hormone signaling and its consequences for thyroid tumor growth present a significant clinical challenge. This dilemma may come from a lack of …

Network And Ecological Methods To Study Enteric Pathogen Co-Infections, Connor L. Klopfer

Graduate College Dissertations and Theses

Diarrhea remains a leading cause of childhood morbidity and mortality, especially inchildren under 5 years of age. Enteric pathogen co-infection has been found to cause increased diarrheal severity and some pathogens may work in tandem to enhance infection. It is important to identify patterns of pathogen co-infection and their impact on diarrhea to inform intervention strategies for improving child health. In this thesis, I use data from the MAL-ED and PROVIDE birth cohort studies in Bangladesh to generate bipartite networks that represent the relationship between stool samples and pathogens. I randomly rewire the network while preserving connectivity to randomize the …

Determinants Of Antibody Immunity In Flavivirus Infections And Immunization, Huy Tu

Graduate College Dissertations and Theses

The most significant arthropod-borne viral infections in modern history are caused by species of the Flavivirus (FV) genus due to their global transmission. While immunization is effective at decreasing the burden imposed by some FV, vaccines for other FV such as Dengue virus (DENV) and Zika virus (ZIKV) are still in development or not widely available. A better understanding of the protective immune response, specifically the antibody response, to DENV and ZIKV will advance the vaccine development endeavors for these viruses. Utilizing longitudinal samples from controlled human immunization/challenge studies and natural infections, we investigated the antibody response to these viruses …

Structural Characterization Of The Novel Flightin Domain Wyr And Its Defining Role In The Thick Filament Structure And Mechanics, Lynda Menard

Graduate College Dissertations and Theses

The evolutionary success of Insecta has been attributed largely to the development of efficient means of motility: flight powered by muscle architecture harboring a largely conserved yet tunable system of power relay. The indirect flight muscle (IFM) of Drosophila melanogaster is a well-studied model for dissection of the structural and mechanical means by which muscle operates and evolves. Striated muscle, conserved throughout Animalia, is demarcated by an ordered array of thick- and thin-filaments prominently composed of the proteins myosin and actin. Flightin (fln) is a myosin binding thick filament protein essential for IFM stability, structure and function. The manner by …

Effect Of Long-Term Dietary Fat Quality On Metabolic Health With A Special Focus On Dairy Fat, Allison L. Unger

Graduate College Dissertations and Theses

Diet, and particularly dietary fat quality (i.e., fatty acid composition), is a significant modifiable risk factor in the development of metabolic diseases. However, whether the manipulation of long-term dietary fat quality may serve as an effective dietary strategy to mitigate metabolic disease risk during aging is not well defined. Accordingly, this work sought to investigate the role of life-long consumption of bioactive fatty acids from various food sources, and particularly dairy fat, on health maintenance and metabolic disease risk later in life. To address this issue, I assessed how long-term supplementation of dairy fat (butter oil), echium oil, or fish …

Lcms-Based Analysis Explains The Basis Of Oxidative Resistance In Selenium-Containing Thioredoxin Reductase, Daniel Haupt

Graduate College Dissertations and Theses

Selenocysteine (Sec) is referred to as the 21st proteogenic amino acid and is found in place of the redox-sensitive amino acid cysteine (Cys) in a small number of proteins. Sec and Cys carry out similar chemistry and are structural isomers save for a single atom difference; the former contains selenium (Se), while the latter contains sulfur (S) in the identical position. Sec poses a high bioenergetic cost for its synthesis and subsequent incorporation into protein not shared by Cys. Since Sec’s discovery in 1976, scientists have debated why certain proteins express Sec while others express Cys. In recent years, it …

It’S More Than Profits: Examining Perceived Success In Agritourism, Lindsay Quella

Graduate College Dissertations and Theses

Over the last 20 years, small- and medium-sized farm owners are increasingly interested in participating in agritourism and direct sales in order to boost income, provide family employment, and educate the public about agriculture, among other reasons. A growing body of research has focused on agritourism from the provider perspective, but more research is needed in order to identify supports and barriers for agritourism operators. In order to address this gap, we first investigated how operators themselves define success, before studying the attributes that are associated with success in agritourism. While prior research acknowledges the strong influence of non-economic factors …

Analysis Of Host Factors Involved In Regulating Hiv-1-Induced Syncytium Formation, Emily Elizabeth Whitaker

Graduate College Dissertations and Theses

Human Immunodeficiency Virus type 1 (HIV-1) is a retrovirus and the causative agent of Acquired Immunodeficiency Syndrome (AIDS). HIV-1 can spread through multiple modes of transmission including cell-to-cell transmission between CD4+ T cells at a transient junction known as the virological synapse (VS). The VS forms upon HIV-1 Envelope (Env) on the surface of an infected (producer) cell binding CD4 on an uninfected (target) cell. While the VS typically resolves with complete cell separation and transfer of virus particles, Env can occasionally facilitate cell-cell fusion at this site, forming a multinucleated infected cell (syncytium). Excessive syncytium formation is prevented by …

The Effects Of Dietary Yeast Extracts On Rumen Microbiota And Fermentation In A Dual-Flow Continuous Culture Fermentation System, Lauren Baker

Graduate College Dissertations and Theses

Dietary yeast supplements are a popular feed additive in ruminant diets as its inclusion can favorably alter the rumen microbiota and fermentation, and subsequently improve animal health and production. Yeast are a rich source of amino acids, peptides, organic acids, carbohydrates, lipids, vitamins, and minerals. Inclusion of nutrient-rich yeast and yeast extracts in the diet promote the growth of select groups of rumen microbiota, subsequently improving digestibility, volatile fatty acids, and pH profile. However, the large variability within yeast types and composition has created inconsistent results on these parameters, and further investigation into yeast product variability is crucial for understanding …

The Impacts Of Asian Longhorned Beetle On Forests In Southern New England, Olivia Fay Box

Graduate College Dissertations and Theses

Over the past several decades, the United States has been experiencing an influx of nonnative pests due to increased globalization, and many of these pests have the potential to permanently alter the composition, structure, and function of forests. Asian longhorned beetle (ALB) is an invasive pest that came into Worcester county, MA in 2008, where the first instance of this species invading both urban and natural forested areas was documented. Within the quarantine area for this novel invasion, 30,000 trees were removed over the course of 10 years as part of management efforts focused on harvesting all host species, primarily …

Organic Amendments Alter Soil Hydrology And Belowground Microbiome Of Tomato (Solanum Lycopersicum), Taylor Readyhough

Graduate College Dissertations and Theses

Manure-derived organic amendments are a cost-effective tool that provide many potential benefits to plant and soil health. For example, amendment applications may increase soil fertility, improve soil structure, stimulate microbial activity, and suppress plant pathogens. Yet, responses to these applications may have unintended consequences. Inherent variability in the physical, chemical, and biological characteristics of these materials can result in inconsistent outcomes observed after their application. These differences are manifested in plant growth, soil physiochemical properties, and soil microbial community composition. Popular manure-derived organic amendments include dairy manure compost and poultry manure pellets. Dairy manure is an abundant resource on many …

Assessing Chemical And Biological Recovery From Acid Rain Deposition In Montane Vermont Lakes, Sydney Diamond

Graduate College Dissertations and Theses

Vermont’s inland lakes are changing rapidly in response to anthropogenic disturbance pressures. While changes in water chemistry are well documented across the state, the biological response of primary producer communities to these shifts remains poorly understood. This project investigated the response of phytoplankton communities to the interacting effects of recovery from acidification and climate change in high-altitude lakes. We analyzed long-term monitoring and meteorological data in four of Vermont’s acid-impaired lakes and found that as pH and acid-neutralizing capacity has increased, so have concentrations of dissolved organic carbon (DOC) in most lakes. To assess the biological response to these processes, …

Healthcare Professionals’ Perceptions Regarding The Nutrition Of Dairy And Plant-Based Dairy Alternatives, Bridget Clark

Graduate College Dissertations and Theses

Plant-based (PB) dietary patterns have seen an upsurge in popularity over the past two decades. With this, has come an increase in consumption of PB alternatives to animal food products, including alternatives to dairy. However, because PB dairy alternatives are nutritionally different from dairy, there is concern that consumers of these products may unknowingly fall short on essential nutrients in their diet. Healthcare providers are key sources of nutrition information for U.S. consumers. This work examined U.S. healthcare professionals’ beliefs and recommendations regarding dairy and PB dairy alternatives. Two methods were used: (1) analysis of all public comments submitted the …

The Role Of Peroxiredoxin 4 And Er Redox Stress In Idiopathic Pulmonary Fibrosis, Evan Elko

Graduate College Dissertations and Theses

Idiopathic Pulmonary Fibrosis (IPF) is a disease that is characterized by excessive scar formation in the lung. IPF is a disease associated with aging and is believed to be the manifestation of repeated micro-injuries and lack of adequate repair over time. Notably increases in endoplasmic reticulum (ER) stress of epithelial cells and excessive epithelial cell death have been identified as processes that drive the progression of fibrosis. Every year 34,000 people in the United States are diagnosed with Idiopathic Pulmonary Fibrosis (IPF). The average survival time for these patients is only 3-5 years after diagnosis. Two available drugs stabilize patients …

The Effect Of Physically Effective Undegradable Neutral Detergent Fiber And Rumen Fermentable Starch On Lactating Holstein Cows, Katherine Mae Smith

Graduate College Dissertations and Theses

In the dairy industry, a common way of adding energy to the diet is in the form of fermentable starch. However, an overabundance of fermentable carbohydrates can cause a buildup of volatile fatty acids that exceed the buffering capacity of the rumen. These changes can lead to negative health consequences such as subacute rumen acidosis and milk fat depression. Not only does a cow need readily fermentable sources of energy in her diet, but she also needs physically effective structural carbohydrates.Fiber has been a difficult portion of the diet to characterize as both the chemical and physical properties are important …

Autonomic Reactivity In Emerging Adulthood : Relationships Between Cyberbullying , The Autonomic Nervous System, And Clinical Outcomes., Aya Cheaito

Graduate College Dissertations and Theses

With the advent of the COVID-19 pandemic, online environments have become critical ways of connecting among college students. With the increase in online interactions, cybervictimization has been identified as a public health issue. This study aims to examine whether cybervictimization among college students is associated with clinical adjustment outcomes such as depression and alcohol consumption. This study also aims to examine whether reactivity in the two branches of the autonomic nervous system (sympathetic and parasympathetic) jointly moderate the relationship between cyberbullying and depression/alcohol consumption, indicating sensitivity to the environment. Participants (n =164, 69% female, M age = 19.92, SD = …

Sarracenia Purpurea As A Model System For Aquatic Ecosystem State Changes And Their Impact On Bacterial Communities, Amanda Claire Northrop

Graduate College Dissertations and Theses

Aquatic ecosystems can undergo abrupt and long-lasting transitions from one state to another, often with negative ecological and economic consequences. With anthropogenic enrichment, aquatic ecosystems such as lakes and ponds may shift rapidly from an oligotrophic, clear water state to a eutrophic, turbid state. These shifts, or state changes, generally occur due to a phenomenon called hysteresis in which the relationship between a driving variable and ecosystem variable depend on the current state of the ecosystem. Such dynamics often make recovery difficult or impossible. Though state changes in aquatic ecosystems have been studied extensively since the 1970s, there have been …

Unique Genomic And Phenotypic Responses To Extreme And Variable Ph Conditions In Purple Urchin Larvae, Strongylocentrotus Purpuratus, April Dawn Garrett

Graduate College Dissertations and Theses

Given the unprecedented increases in atmospheric carbon dioxide and its projected negative impacts on organismal ecology and physiology, it is crucial to understand if and how organisms will withstand such environmental changes. Due to the oceans’ service as a carbon sink, marine organisms face the added stressor of ocean acidification (OA), the process by which carbon dioxide mixes with water and decreases pH while simultaneously depleting the seawater of calcium carbonate. Marine organisms that rely on calcium carbonate for exoskeleton development are considered particularly vulnerable to OA, though previous results vary among species, leading to the question of who the …