Life Sciences Commons^™

Metabolic Foundations Of Exercise-Induced Cardiac Growth., Kyle Fulghum

Electronic Theses and Dissertations

Regular aerobic exercise promotes physiological cardiac growth, which is an adaptive response thought to enable the heart to meet higher physical demands. Cardiac growth involves coordination of catabolic and anabolic activities to support ATP generation, macromolecule biosynthesis, and myocyte hypertrophy. Although previous studies suggest that exercise-induced reductions in cardiac glycolysis are critical for physiological myocyte hypertrophy, it remains unclear how exercise influences the many interlinked pathways of metabolism that support adaptive remodeling of the heart. In this thesis project, we tested the general hypothesis that aerobic exercise promotes physiological cardiac growth by coordinating myocardial metabolism to promote glucose-supported anabolic pathway …

Re-Engineering Cardio-Oncology Testing Using Biomimetic Heart Slice Cultures., Jessica Miller

Electronic Theses and Dissertations

28% of drug withdrawal from the market are due to unforeseen disruptions in cardiomyocyte contractility and electrophysiology. The most commonly used platforms for drug testing are in vivo animal models and in vitro cell culture models. While both have been of paramount importance for the discovery and detection of many cardiotoxicities and mechanisms of action, they lack the ability to model an intact human myocardium. This work aims to establish cardiac tissue slices, which are 300-micron thin tissue sections taken from the left ventricular myocardium, as an alternative platform for cardio-oncology studies, specifically cardiotoxicity testing. Additionally, this work aims to …

Establishing The Efficacy Of Non-Cellular Components Of Adipose-Derived Stromal Vascular Fraction In Promoting Angiogenesis., Daniel Benson

Electronic Theses and Dissertations

Microvascular disease is hallmarked by pathophysiological conditions such as endothelial senescence, intimal thickening which impairs vasodilation, and regression of the capillary beds causing tissue ischemia in the myocardium or in peripheral vascular networks. Adipose-derived stromal vascular fraction (SVF) has previously demonstrated the ability to revascularize tissue. Increasing evidence shows that regenerative cells elicit their therapeutic benefit by paracrine mechanisms, leaving open extracellular vesicles (EVs) as a potential crux of the cell therapy paradigm. To test this idea, three types of gelatin methacrylate hydrogels were employed: SVF gels, EV gels derived from SVF, and blank control gels, which were used in-vitro …

Alcohol, Stress, And Sex In The Bed Nucleus Of The Stria Terminalis, Nicholas Burski

Electronic Theses and Dissertations

Alcohol use disorder (AUD) costs the U.S. billions of dollars each year and is a leading cause of preventable death. AUD leads to many health complications, and those who suffer from AUD will often have stress and anxiety disorder comorbidities. To better understand this connection between AUD and stress and anxiety disorders, restraint stress (RS) and chronic-intermittent ethanol exposure (CIE) procedures were used on rats to analyze neuroinflammation via ELISA in the infralimbic and prelimbic cortices, and the bed nucleus of the stria terminalis (BNST). Levels of proinflammatory cytokines, TNF-α and IL-1β, were found to be elevated across different tests …

Investigating The Pi3k/Akt/Atm Pathway, Telomeric Dna Damage, T Cell Death, And Crispr/Cas9-Mediated Gene Editing During Acute And Chronic Hiv Infection, Sushant Khanal

Electronic Theses and Dissertations

Human Immunodeficiency Virus (HIV) infection initiates major metabolic and cell- survival complications. Anti-retroviral therapy (ART) is the current approach to suppress active HIV replication to a level of undetected viral load, but it is not a curative approach. Newer and sophisticated gene editing technologies could indeed be a potent antiviral therapy to achieve a clinical sterilization/cure of HIV infection. Chronic HIV patients, even under a successful ART regimen, exhibit a low-grade inflammation, immune senescence, premature aging, telomeric DNA attrition, T cell apoptosis, and cellular homeostasis. In this dissertation, we investigated CD4 T cell homeostasis, degree of T cell apoptosis, an …

Ecological Implications Of Intraspecific Behavioral Variation In A Small Mammal Community, Allison Brehm

Electronic Theses and Dissertations

Variation among individuals is at the root of all evolution by means of natural selection. However, only in recent years has intraspecific behavioral variation been embraced as a potential driver of community and ecosystem processes, rather than considered statistical noise. Animal personalities, or behavioral differences between conspecifics that are consistent across time and contexts, are one such form of variation that has received considerable attention in the last two decades. Investigations of the ecological and ecosystem consequences of personality variation is at the current forefront of the field, but much work on this topic remains conceptual. Here, I apply large-scale …

Telomerase Reverse Transcriptase Marks A Novel Population Of Adult Stem Cells In The Mouse Brain That Respond To Metabolic Interventions By Modulating Adult Brain Plasticity, Gabriel S. Jensen

Electronic Theses and Dissertations

Telomerase reverse transcriptase (TERT) is expressed by quiescent adult stem cells (qASC) in numerous adult murine and human tissues but has never been explored in the adult brain. Here, these data demonstrate that TERT+ cells in the adult mouse brain represent a novel population of multipotent qASCs. TERT+ cells were localized to numerous classical neuro/gliogenic niches including the ventricular-subventricular zone, hypothalamus and olfactory bulb, as well as newly discovered regions of adult tissue plasticity such as the meninges and choroid plexus. TERT+ cells expressed neural stem cell markers such as Nestin and Sox2, but not markers of activated stem/progenitor cells, …

The Rapid Enumeration Of A Mixed Culture Of S. Cerevisiae & L. Plantarum In Beer Using Image-Based Cytometry, Kevin M. Kennedy

Electronic Theses and Dissertations

Mixed cultures are prevalent in the food industry. From sour beer to sourdough bread, mix culture popularity is growing. A number of microbiological mixtures are used in these unique fermenting processes to create distinctive flavor profiles of consumers’ favorite foods. Although mixed cultures seem ubiquitous, they are often not well enumerated. The aim of this thesis was to create a novel rapid image-based cytometry method to enumerate mixed cultures in beer. Imaged-based cytometry can be used to rapidly enumerate mixed microbial cultures, as opposed to traditional plate counting methods that can take days to grow and count. A novel method …

Genetic Sources Of Resistance To Potato Blackleg Soft Rot Caused By Dickeya Dianthicola, Lucas K. Heroux

Electronic Theses and Dissertations

Solanum tuberosum L. is the world's most important non-cereal food crop, capable of producing more food per land unit on less water than any other crop. Only rice, wheat, and maize are produced in larger quantities than potato. The potato tuber, a modified stem turned storage organ is nutrient dense and a staple in diets across the world. The potato crop is expected to grow and contribute significantly to the global food supply. However, potato production has increasingly been threatened by unfavorable environmental conditions, and susceptibility to pest and disease. Perhaps the most famous of all the Irish Potato Famine …

Genetic Determinants Of Primary Nociceptor Sensitivity In Drosophila Melanogaster, Christine Hale

Electronic Theses and Dissertations

Abnormal pain affects ~50 million adults nationwide. With many of the current treatment options for chronic pain, such as opioid analgesics, carrying side effects such as the threat for addiction, research into safer and more effective options for chronic pain relief is crucial. Abnormal alterations in nociceptive sensitivity, which is the sensitivity of peripheral sensory neurons that detect noxious stimuli, can underlie, and perpetuate chronic pain. However, much is still unknown about the mechanism of how these abnormal alterations in sensitivity occur. To help elucidate genetic components controlling nociceptive sensitivity, the Drosophila melanogaster larval nociception model has been used …

3d Computer Modeling Offers New Insights Into Diatom Ecology, Joseph Mohan

Electronic Theses and Dissertations

Algae supply over half of the Earth’s global primary production and form the base of almost all aquatic food networks. Thus, changes in algal productivity or composition will induce profound shifts in many ecosystems. This research is guided by two questions. Herein I ask if 3D models of algae can be created accurately enough to use for research applications? If they can be accurately created, then how can these models be used to advance our understanding of functional trait evolution and paleoecology? Herein, I develop 3D computer models for estimating the volume of individual algae and their parts. I also …

Using Soil Testing Data To Examine Organic Carbon Changes During The Past 27 Years In Maine Agricultural Soils, Andrew Chase

Electronic Theses and Dissertations

Agricultural soils may act as a source or a sink for carbon (C) in the global C cycle. With rising atmospheric CO2 levels, C sequestration in soils may play an important role in climate change mitigation. Soil organic carbon (SOC) also contributes to key aspects of soil health and fertility, such as aggregation, water-holding capacity, microbial biomass, and nutrient mineralization. Although SOC may be calculated from estimates of soil organic matter (SOM) obtained by loss-on-ignition (LOI), factors such as sample clay concentration and combustion temperature introduce error into estimates of SOM. We explored the potential for an extensive collection of …

Northern White-Cedar Stand Structure, Composition, And Ecophysiology: Implications For Management And Climate Change Resilience, Katlyn Schulz

Electronic Theses and Dissertations

Low rates of regeneration and recruitment for northern white-cedar (Thuja occidentalis) have been observed in lowland forests in some parts of its range, especially in comparison to its main tree competitor, balsam fir (Abies balsamea). In addition, climate projections suggest that suitable habitat conditions for the two species will decline in the northeastern United States and adjacent Canada due to widespread warming and increased variation in the timing and amount of precipitation. As such, future climate conditions may alter the competitive dynamics of these two species, which poses a major challenge for mitigating the negative effects of climate change through …

Career Readiness Of Recently Credentialed Registered Dietitian Nutritionists, Maegan Perrault

Electronic Theses and Dissertations

This study assessed the perceptions of career preparedness of recently credentialed Registered Dietitian Nutritionists (RDNs) (< 5 years/post credential) and their experiences in undergraduate, supervised practice, and/or graduate programs. All participants were recruited from a randomized sample from the databank of the Commission on Dietetic Registration (CDR). Participants were recently credentialed RDNs (≤5 years) from the United States (U.S). A survey was designed to evaluate the RDNs perceived ability to perform the 2017 Accreditation Standards for Nutrition and Dietetics Internship Program competencies as a working RDN. Participants were also invited to share their insights by answering open-ended questions regarding their experiences as a student in undergraduate, supervised practice, and/or graduate programs. Survey responses were analyzed overall and were grouped into six domains of practice, corresponding to the Standards of Professional Practice (SOPP) domains of the Academy of Nutrition and Dietetics. The level of education, type of undergraduate degree and type of dietetic internship were evaluated for their impact on perceived career preparedness overall and within the domains of the SOPPs. Respondents agreed that they felt prepared overall to practice as an RDN in the work setting as indicated by a mean score of 2.05 (SD=0.63). Respondents felt least prepared in the competency of “analyzing quality financial and productivity data for use in planning” M= 3.16 (SD=1.66). Conversely, respondents strongly agreed that they were able to “incorporate critical thinking in overall practice” M=1.48 (SD=.60) and “practice according to the Code of Ethics” M=1.48 (SD=.64). The domain rated strongest among respondents was Domain 2: Competence and Accountability, M=1.72 (SD = 0.56). The domain with the weakest score was Domain 6: Utilization and Management of Resources M=2.93 (SD = 1.31). There were no significant differences in perceived career preparedness overall, or by domains of practice in regard to the level of education, type of undergraduate degree, and type of dietetic internship. Knowledge gaps were identified in clinical experiences and business management. In conclusion, recently credentialed RDNs in the US who have completed ACEND® programs feel ready to practice. The type of dietetic internship, level of education, and type of undergraduate degree were not significant factors in their perceived career preparedness overall or by domain of practice. The domain of management of resources and the theme of business management were consistently the areas identified as knowledge gaps. These areas should be improved upon within dietetic programs at all levels to ensure students continue to feel prepared to work in the dynamic field of healthcare.

Regulation Of Line-1 In Developing Oocytes And The Impact On The Ovarian Reserve, Rose Besen-Mcnally

Electronic Theses and Dissertations

In humans and mice, the ovarian reserve (OR) is established during a lengthy process that starts during early embryogenesis with germ cell specification and culminates in the first weeks after birth when primordial follicles (PF) are formed. OR establishment is an important process which influences the fertile lifespan and fecundity of the individual. Fetal oocyte attrition (FOA) has been identified as a critical developmental event that regulates how many oocytes survive and contribute to the final OR. In addition to FOA, OR size and quality also depend on efficiency of meiotic recombination. Chromosome asynapsis and unrepaired meiotic double-strand breaks (DSB) …

Contact Dewatering Of Cellulose Nanofibers For Biopolymer Composite Applications, Alexander Collins

Electronic Theses and Dissertations

Cellulose Nanofibrils (CNFs) are promising materials for reinforcement of polymer matrices attributable to their impressive physical and mechanical properties, as well as their biodegradability. However, the utilization of these materials in composites is made challenging by the water content of CNF slurries, the tendency of CNFs to agglomerate as they dry, and incompatibility between hydrophilic CNFs and hydrophobic polymer matrices. The most commercially viable drying methods to produce small-scale dry CNFs, such as spray drying, are very energy intensive, can only dry the materials down to micron-scale agglomerates, and do not preserve fibrillar aspect ratios. “Contact dewatering,” or the removal …

Biophysical Interactions And Social Perceptions Of Ixodes Scapularis (Acari: Ixodidae) Exposure Risk Due To Climate Change, Brittany Schappach

Electronic Theses and Dissertations

Increased temperature variances are being recorded in Maine due to climate change, contributing to increased densities of blacklegged ticks (Ixodes scapularis) and concomitant increase in reported cases of tickborne diseases across the state. Understanding the interactions between mean temperature and temperature variance in relation to overwinter tick survival is crucial in understanding the tick’s geographical expansion limits to create better prediction models for their expansion. The goals of this study were to determine the interacting microclimate effects of winter temperature variance and mean temperatures on tick mortality, which month nymphal blacklegged ticks experience highest mortality, and assess the connection between …

Understanding The Contribution Of Gα To The Yeast Pheromone Response, Cory Johnson

Electronic Theses and Dissertations

G-protein coupled receptors (GPCRs) are the target of approximately 35% of all FDA-approved pharmaceuticals. This is because GPCRs regulate different cellular signals including control of cell polarity. The yeast, Saccharomyces cerevisiae, use a GPCR for mating which induces chemotropic growth and morphogenesis toward a mate. In mammalian cells, signaling downstream of the receptor is primarily conducted by the Gα subunit of the large G-protein. In the yeast pheromone response little is known about Gα’s contribution to signaling and the Gβγ subunit is the primary known contributor. This begs the question, what is the contribution of Gα to the yeast pheromone …

Mitochondria Mediated Outcomes Of Developmental Exposure To Low-Level Chemical Mixtures In Zebrafish Danio Rerio, Remy Babich

Electronic Theses and Dissertations

Exposure to drinking water contaminants has been linked to developmental outcomes in both epidemiological and model organism studies. However, low level mixture effects, on early development has yet to be explored. It is hypothesized that early chemical exposures may increase disease susceptibility later in life. This work aimed to investigate impacts of a variety of chemicals and concentrated on metals arsenic (As), cadmium (Cd), vanadium (V), and lead (Pb) due to their presence in drinking water and known developmental toxicity. To determine the effects of a metal and organic contaminant co-exposure, the ubiquitously used herbicide glyphosate was also explored. The …

Quantifying Spatial Heterogeneity Of Wild Blueberries And Crop Water Stress Monitoring Using Remote Sensing Technologies, Kallol Barai

Electronic Theses and Dissertations

The wild blueberry is one of the major crops of Maine, with significant economic value and potential health benefits. Due to global climate change, drought impacts have been increasing significantly in recent years in the northeast region of the USA, causing significant economic losses in the agricultural sectors. It has been predicted to increase further in the future. Changing patterns of the elevated atmospheric temperatures, increased rainfall variabilities, and more frequent drought events have made the wild blueberry industry of Maine vulnerable, suggesting the adoption of novel approaches to mitigate the negative impacts of global climate changes. Also, wild blueberry …

Neural Stem Cells: Age-Dependent Outcomes During Viral Infections In The Central Nervous System, Manisha N. Chandwani

Electronic Theses and Dissertations

Viral infections in the central nervous system (CNS) are associated with neurodevelopmental and neurobehavioral deficits. The outcomes of viral infections can be driven by damage and death of neurons. Neural stem cells (NSCs) play key roles in neurodevelopment, repair, and physiological brain function. During a viral infection, NSC activity can disturbed by direct infection of NSCs by the virus or by anti-viral immune response. Here, we aimed to assess whether the anti-viral immune response can impact NSC activity during an immunocompetent response in the adult brain. We utilized a transgenic mouse model of Measles virus infection where only the CNS …

Novel Signal Sequences And Fusion Partners For Paratransgenesis In Asaia, Christina Grogan

Electronic Theses and Dissertations

Mosquitoes transmit many pathogens that cause human disease. One such disease, malaria, is caused by parasites in the genus Plasmodium, infecting over 200 million people and killing over 600,000 per year. Current strategies to control vector-transmitted diseases are increasingly undermined by mosquito and pathogen resistance. Research has turned to additional and novel methods of control, such as altering the microbiota of the vectors. In this method, called paratransgenesis, symbiotic bacteria are genetically modified to affect the mosquito’s phenotype by engineering them to deliver antiplasmodial molecules into the midgut to kill parasites. These molecules must be released by the …

Investigating Host Defenses Of North American Salamanders Against The Recently Emerged Chytrid Pathogen, Batrachochytrium Salamandrivorans, Kenzie Pereira

Electronic Theses and Dissertations

A recently emerged chytrid fungal pathogen, Batrachochytrium salamandrivorans (Bsal) threatens salamander biodiversity. Bsal susceptibility varies between and within salamander species, but little is known about the mechanisms underlying these differences. Susceptibility is likely influenced by numerous interacting factors, but my dissertation studied the role of host immune responses.

My first aim investigated between species differences by studying the bioactive properties of salamander skin peptides against Bsal and the related pathogen, B. dendrobatidis (Bd). Skin peptides were collected from five salamander species, used for in vitro assays, and analyzed by RP-HPLC. While skin peptides from one …

Identification And Characterization Of Genetic Elements That Regulate A C-Di-Gmp Mediated Multicellular Trait In Pseudomonas Fluorescens, Collin Kessler

Electronic Theses and Dissertations

Microbial communities contain densely packed cells where competition for space and resources are fierce. These communities are generally referred to as biofilms and provide advantages to individual cells against immunological and antimicrobial intervention, dehydration, and predation. High intracellular pools of cyclic diguanylate monophosphate (c-di-GMP) cause cells to aggregate during biofilm formation through the production of diverse extracellular polymers. Genes that encode c-di-GMP catalytic enzymes are commonly mutated during chronic infections where opportunists display enhanced resistance to phagocytosis and antibiotics. Our lab uses an emergent multicellular trait in the model organism Pseudomonas fluorescens Pf0-1 to study the emergence of c-di-GMP mutations …

Prevention Of Inflammatory Bowel Disease By Broccoli-Sourced And Microbially-Produced Bioactives, Johanna M. Holman

Electronic Theses and Dissertations

Inflammatory Bowel Diseases (IBD) are chronic, reoccurring, and debilitating conditions characterized by inflammation in the gastrointestinal tract, some of which can lead to more systemic complications and can include autoimmune dysfunction, a change in the taxonomic and functional structure of microbial communities in the gut, and complicated burdens in a person’s daily life. Like many diseases based in chronic inflammation, research on IBD has pointed towards a multifactorial origin involving factors of the host’s lifestyle, immune system, associated microbial communities, and environmental conditions. Too often, research focuses on just one aspect of IBD or uses one model with a narrow …

Developing And Characterizing A Novel Tempo Cnf Hydrogel Adjuvant And Delivery System For Aquatic Vaccines, Kora Kukk

Electronic Theses and Dissertations

Aquaculture is a large part of the food production sector which is greatly expanding. One of the largest losses in aquaculture is due to pathogens. Current solutions for protecting farmed finfish from pathogens can be very expensive with variable efficiency. Current disease prevention strategies include vaccination. Types of vaccines include immersion vaccines, feed vaccines, and injectable vaccines. The most popular solution is oil-based injectable vaccines due to its protection. However, the oil-based adjuvant used in most of these formulations causes adverse reactions in the fish including reduced growth. These vaccines require multiple administrations throughout the fish’s lifetime causing unwanted handling …

Remotely Sensed Assessment Of The Preferred Habitat Of Alexandrium Catenella In The Gulf Of Maine And The Bay Of Fundy, Andre F. Bucci

Electronic Theses and Dissertations

Harmful Algal Blooms (HABs) of the toxic dinoflagellate Alexandrium catenella are an annually recurring problem in the Gulf of Maine (GoM), resulting in risks to human health and substantial economic losses due to shellfish harvesting closures. The monitoring approaches in the region are restricted to real-time identification of the HABs events, when they are clearly underway and already causing deleterious effects to the environment. To fully function as an early warning system rather than an immediate response, monitoring strategies need to be focused on environmental conditions preceding A. catenella HABs. However, the current understanding of the preferred habitat for A. …

Sustainability In Forest Operations: Harvesting On Fragile Ground, Best Management Practices Assessment, Perspectives On Forest Certification, And Life Cycle Assessment Of Forest Products, Alex Kunnathu George

Electronic Theses and Dissertations

Sustainably managed forest and forest products are at the center as the world move toward a green economy. Sustainable forest management (SFM) cannot be possible without sustainability in forest operations, which includes quality optimization and ergonomics along with environment, economics, and people. To excel in the above-mentioned performance areas, all tools need to be employed to generate knowledge that enables forest managers and policymakers to preserve forests as a renewable resource. Machine cost and productivity estimation, forest growth modeling (Forest Vegetation Simulator), soil erosion modeling (Universal Soil Loss Equation), forestry best management practices (BMP) assessment, questionnaire survey, and life cycle …

Flora Of Doe Mountain Recreation Area, Johnson County, Tennessee, Benjamin Mccullough

Electronic Theses and Dissertations

A botanical inventory of Doe Mountain Recreation Area (DMRA) in northeastern Tennessee was conducted to help guide conservation-based management. A total of 484 species were found in DMRA, comprising 94 families, and 285 genera, 10 species listed in the state rare plant list, and 76 exotic species. Two species, Liatris virgata and Lycopodiella inundata, were new state records. Water in the Lycopodiella seep was an order of magnitude more acid than at other sites. An analysis of the wildland-urban interface showed that only 13% of the area was classified as uninhabited. The inventory-invasion index, introduced to quantify the relative …

Characterization Of Microbotryum Lychnidis-Dioicae Secreted Effector Proteins That Manipulate Its Host Plant, Silene Latifolia., Ming-Chang Tsai

Electronic Theses and Dissertations

The smut fungal species Microbotryum lychnidis-dioicae is an obligate phytopathogen colonizing the plant host, Silene latifolia. A significant feature of M. lychnidis-dioicae infection is that the fungus can replace pollen on the anthers of susceptible host plants with fungal teliospores, thus earning the fungus the name: anther smut disease of flowers. The fungus synthesizes and secretes effector proteins into the cells of the plant host during infection, and the protein-protein interactions may interfere with and modify metabolism, plant development, and gene expression of the host to allow fungal colonization. Two potential fungal effector proteins, MVLG_06175 and MVLG_05122, were identified …