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Towards A Structural Understanding Of Spore Germination In Clostridium Difficile, Chloe M. Adams

Graduate College Dissertations and Theses

Clostridium difficile is a Gram-positive bacterium that causes a toxin-mediated disease, typically in individuals whose normal intestinal flora has been compromised by antibiotic therapy. C. difficile is naturally resistant to many antibiotics and produces spores that can withstand harsh environmental conditions and many disinfectants, making the infection difficult to clear and easy to spread. The infection begins when spores from the environment are ingested and germinate upon exposure to taurocholate and glycine in the digestive tract. This germination process is required to initiate infection and thus represents a good target for the development of novel therapeutics. Although spore germination is …

The Influence Of Prenatal Stress On Behaviors Associated With Schizophrenia And Autism Spectrum Disorder., Harold Bauerle

Graduate College Dissertations and Theses

Disorders such as schizophrenia (SCZ) and austism spectrum disorder (ASD) have long been associated with prenatal stress. In these three experiments, we attempted to correlate stress during gestation with behaviors considered to have good facial validity with SCZ and ASD in both juvenile and adult animals. To differentiate the effects of prenatal stress (PS) from the effects of early life stress due to a dam's behavior (MS), half of offspring animals were cross fostered to dams treated in the alternative condition as the offspring during pregnancy in experiments 2 and 3. In experiment 1, but not in 2 or 3, …

Swede Midge, Contarinia Nasturtii (Diptera: Cecidomyiidae), Response To Brassica Oleracea In Simulated Intercropping Systems, Gemelle Laureen Brion

Graduate College Dissertations and Theses

Monoculture agriculture has developed as a result of the Western agricultural growth model, which emphasizes reduced on-farm labor and maximum yield. As a result soil health, which is reliant on a diversity of soil-dwelling organisms, is compromised, pest problems are intensified, and biodiversity is lost when vast land areas are devoted to simplified vegetation schemes. There has been a tremendous rise in interest in alternative cropping schemes. The traditional practice of intercropping has received renewed interest as the emphasis on agricultural growth shifts from a purely development-based model to one of conservation and enhanced biodiversity.

Although intercropping has shown promising …

The Molecular Evolution Of Non-Coding Dna And Population Ecology Of The Spiny Softshell Turtle (Apalone Spinifera) In Lake Champlain, Lucas Edward Bernacki

Graduate College Dissertations and Theses

ABSTRACT

Spiny softshell turtles (Apalone spinifera) occur at the northwest limit of their range in Lake Champlain. This species, although widespread across North America, is listed as threatened in Vermont due to habitat destruction and disturbances of anthropogenic origin. The population of spiny softshell turtles in Lake Champlain is isolated from other North American populations and is considered as an independent management unit. Efforts to obtain information on the biology of spiny softshell turtles in Lake Champlain precede 1936 with conservation measures being initiated in 1987.

Methods of studying spiny softshell turtles in Lake Champlain have included direct …

Determinants Of Termite Species Taxonomic, Phylogenetic, And Functional Diversity In The Amazonian Forest, Cristian De Sales Dambros

Graduate College Dissertations and Theses

The distribution of species in space is determined by the species dispersal capacity, adaptation to environmental conditions, and response to predators and competitors. To determine the importance of dispersal limitation, environmental filtering, and species interactions on the distribution of species in the Brazilian Amazonian forest, I sampled termites in a large area of Brazil. I investigated patterns in species occurrence that could indicate competition and predation structuring termite communities, and analyzed the association of termite abundance and species richness with the density of ant predators. The spatial distribution of termites, and their association with climatic and edaphic conditions were also …

Subsistence Under The Canopy: Agroecology, Livelihoods And Food Sovereignty Among Coffee Communities In Chiapas, Mexico, Margarita Fernandez

Graduate College Dissertations and Theses

One of the most pressing challenges facing the world today is how to sustainably feed a growing population while conserving the ecosystem services we depend on. Coffee landscapes are an important site for research on agrifood systems because they reflect global-scale dynamics surrounding conservation and livelihood development. Within them, we find both what is broken in our global agrifood system, as well as the grassroots struggles that strive to change the system by building socio-ecologically resilient, sustainable livelihoods. Research shows that smallholder shade coffee farmers steward high biodiversity and provide essential ecosystem services. At the same time, studies in the …

The Impact Of Engagement With Community Supported Agriculture On Human Attitude Towards The Sustainable Food Movement, Ariana Margarita Cano

Graduate College Dissertations and Theses

With a total of 164 community supported agriculture programs (CSA), Vermont is leading the "locavore" movement in the United States, ranked number one in the country with the most CSAs and Food Hubs per capita. ("Locavore Index," 2013)

CSAs have a large positive impact on reducing carbon emissions, advancing local economic growth, and promoting healthy lifestyles of consumers. The purpose of this study is to explore the overall experience of individuals in comparison to their current social norm, individual attitudes, identity, and intentions of change, and understand any change overtime in their individual attitude and behavior.

Attitude change was measured …

Sustainable Agriculture In Vermont: Economics Of Climate Change Best Management Practices And The Complexity Of Consumer Perceptions Of Raw Milk, Alexander Paul Helling

Graduate College Dissertations and Theses

Changing weather patterns, the declining social fabric of rural communities, and economic uncertainty increasingly pose challenges to Vermont communities. The socially and environmentally embedded production practices within sustainable agriculture present a potential solution to these problems. In order to make the most of the potential benefits of these practices society must maximize their adoption. This requires an understanding of both farmer adoption of these practices and consumer perceptions of the resulting food products. This thesis contributes two original articles on sustainable agriculture through the analysis of factors driving both farmer adoption and consumer perceptions of products and practices often thought …

Using Mutli Criteria Decision Analysis To Develop Sustainability Assessment Tools: Biomass Supply Chains, Deandra Marie Perruccio

Graduate College Dissertations and Theses

Energy access remains a significant challenge in nations lacking access to resources and strong infrastructure systems, creating barriers to economic development and to increased standards of living. Small scale biomass gasification energy (BGE) systems have been developed to meet energy needs in rural areas, creating synergies between agricultural and agro-forestry systems through utilization of biomass feedstock for energy generation. The sustainability of such systems requires sophisticated planning and coordination of the biomass supply chain.

The goal of this thesis is to investigate and improve structural and process related characteristics of sustainability assessments for small scale bio-energy systems, specifically focusing on …

Thermokarst And Wildfire: Effects Of Disturbances Related To Climate Change On The Ecological Characteristics And Functions Of Arctic Headwater Streams, Julia Rose Larouche

Graduate College Dissertations and Theses

The Arctic is warming rapidly as a result of global climate change. Permafrost - permanently frozen ground - plays a critical role in shaping arctic ecosystems and stores nearly one half of the global soil organic matter. Therefore, disturbance of permafrost will likely impact the carbon and related biogeochemical processes on local and global scales. In the Alaskan Arctic, fire and thermokarst (permafrost thaw) have become more common and have been hypothesized to accelerate the hydrological export of inorganic nutrients and sediment, as well as biodegradable dissolved organic carbon (BDOC), which may alter ecosystem processes of impacted streams.

The biogeochemical …

Dna Glycosylases Remove Oxidized Base Damages From G-Quadruplex Dna Structures, Jia Zhou

Graduate College Dissertations and Theses

The G-quadruplex DNA is a four-stranded DNA structure that is highly susceptible to oxidation due to its G-rich sequence and its structure. Oxidative DNA base damages can be mutagenic or lethal to cells if they are left unrepaired. The base excision repair (BER) pathway is the predominant pathway for repair of oxidized DNA bases. DNA glycosylases are the first enzymes in BER and are responsible for removing base lesions from DNA. How DNA glycosylases remove base lesions from duplex and single-stranded DNA has been intensively studied, while how they act on G-quadruplex DNA remains to be explored.

In Chapter II …

Lidar Remote Sensing Of Forest Canopy Structure: An Assessment Of The Accuracy Of Lidar And Its Relationship To Higher Trophic Levels, Christopher Felix Hansen

Graduate College Dissertations and Theses

Light detection and ranging (LiDAR) data can provide detailed information about three-dimensional forest horizontal and vertical structure that is important to forest productivity and wildlife habitat. Indeed, LiDAR data have been shown to provide accurate estimates to forest structural parameters and measures of higher trophic levels (e.g., avian abundance and diversity). However, links between forest structure and tree function have not been evaluated using LiDAR. This study was designed and scaled to assess the relationship of LiDAR to multiple aspects of forest structure and higher trophic levels (arthropod and bird populations), which included the ground-based collection of percent crown and …

Pasteurization And Its Discontents: Raw Milk, Risk, And The Reshaping Of The Dairy Industry, Andrea M. Suozzo

Graduate College Dissertations and Theses

Milk is something many Americans consume every day, whether over cereal, in coffee or in a cup; as yogurt, cream, cheese or butter. The vast majority of that milk is pasteurized, or heated to the point where much of the bacteria in the milk dies. Pasteurization both slows spoilage of the milk and eliminates potentially harmful bacteria. The fact that we call heat-treated dairy simply "milk" is a testament to pasteurization's widespread proliferation over the past century. Prior to the 1900s, "milk" was raw and unheated, and pasteurized milk was a radically new technology. My research delved into understandings of …

Fgf8a Is Required For Proper Vascularization Of The Zebrafish Retina, Erin Wysolmerski

Graduate College Dissertations and Theses

Fibroblast growth factors (FGFs) are critical in many aspects of embryonic development and other cellular functions including apoptosis, cell adhesion, and proliferation. FGF8a, specifically, is known to initiate retinal ganglion cell (RGC) differentiation along with FGF3 early in retinal development (Martinez-Morales et al., 2005b). There has been little research into later roles for FGF8a in eye development. Here we show mRNA expression of fgf8a in the presumptive RGCs of 2 day-old zebrafish, past the time of RGC differentiation (28-48 hours)(Schmitt and Dowling, 1996). In addition, mRNA expression of putative receptor, FGFR1b, was localized outside the retina on the presumptive vasculature. …

Characterization Of A Non-Canonical Function For Threonyl-Trna Synthetase In Angiogenesis, Adam Christopher Mirando

Graduate College Dissertations and Theses

In addition to its canonical role in aminoacylation, threonyl-tRNA synthetase (TARS) possesses pro-angiogenic activity that is susceptible to the TARS-specific antibiotic borrelidin. However, the therapeutic benefit of borrelidin is offset by its strong toxicity to living cells. The removal of a single methylene group from the parent borrelidin generates BC194, a modified compound with significantly reduced toxicity but comparable anti-angiogenic potential. Biochemical analyses revealed that the difference in toxicities was due to borrelidin's stimulation of amino acid starvation at ten-fold lower concentrations than BC194. However, both compounds were found to inhibit in vitro and in vivo models of angiogenesis at …

Gene Expression Noise In Stress Response As A Survival Strategy In Fluctuating Environments, Javier Garcia-Bernardo

Graduate College Dissertations and Theses

Populations of cells live in uncertain environments, where they encounter large variations in nutrients, oxygen and toxic compounds. In the fluctuating environment, cells can sense their surroundings and express proteins to protect themselves against harmful substances. However, if the stressor appears infrequently or abruptly, sensing can be too costly or too slow, and cells cannot rely solely on it. To hedge against the sudden appearance of a stressor, cell populations can also rely on phenotypic diversification through bet-hedging. In bet-hedging, cells exploit noise in gene expression or use multistable genetic networks to produce an heterogeneous distribution of resistance-conferring protein levels. …

Effects Of Hybridization And Life History Tradeoffs On Pathogen Resistance In The Harvester Ants (Pogonomyrmex), Yainna M. Hernaiz-Hernandez

Graduate College Dissertations and Theses

A fundamental challenge faced by all organisms is the risk of infection by pathogens that can significantly reduce their fitness. The evolutionary dynamic between hosts and pathogens is expected to be a coevolutionary cycle, as pathogens evolve by increasing their level of virulence and hosts respond by increasing their level of resistance. The factors that influence the dynamics of adaptation by pathogen and host in response to one another are not well understood. Social insects live in dense colonies in high-pathogen soil environments, making them an ideal model system to study the factors influencing the evolution of pathogen resistance. In …

Defining Food Agency: An Ethnographic Exploration Of Home And Student Cooks In The Northeast, Maria Carabello

Graduate College Dissertations and Theses

According to popular and academic sources, home cooking is in decline. Nutrition and public health scholars concern that a loss of cooking abilities may diminish individuals' control over their food choices, thus contributing to poor health outcomes. Yet, there are still many unanswered questions. What skills, strategies, and knowledge sets are required to cook a meal on any given occasion? What capacity separates those who cook with ease from those who struggle to incorporate cooking into their daily routines? I propose that this difference is determined by an individual's capacity to employ a range of cognitive and technical skills related …

Effect Of Radiation On Polymerization, Microstructure, And Microbiological Properties Of Whey Protein In Model System And Whey Protein Based Tissue Adhesive Development, Ning Liu

Graduate College Dissertations and Theses

Whey proteins are mainly a group of small globular proteins. Their structures can be modified by physical, chemical and other means to improve their functionality. The objectives of this study were to investigate the effect of radiation on protein-protein interaction, microstructure, and microbiological properties of whey protein-water solutions. Whey protein isolate (WPI) solutions (27-36% protein) were treated with different dosages (10-35 KGy) of gamma radiation. The protein solutions were analyzed for viscosity, turbidity, soluble nitrogen, total plate count, and yeast and mold counts. The interactions between whey proteins were also analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and …

Comprehensive Assessment Of Organic Apple Production In Vermont: Experience From Two Orchard Systems, 2006-2013, Terence L. Bradshaw

Graduate College Dissertations and Theses

Despite substantial consumer demand and willingness to pay premium prices for organically grown fruit, apple growers in Vermont and other New England states have been slow to adopt certified organic practices. Barriers cited in the past to increased adoption of organic apple production in the region include susceptibility of traditionally grown cultivars to apple scab, lack of effective insect pest management materials, and few available effective options for fruit thinning. Recent changes in apple cultivar plantings in the region, introduction of new insect pest management materials, and advances in crop thinning justified an evaluation of organic apple production systems containing …

The Efficacy And Non-Target Impacts Of An Organic Disease Management System Containing Biostimulants Compared With Two Sulfur-Based Systems On Four Apple Cultivars In Vermont, Ann L. Hazelrigg

Graduate College Dissertations and Theses

Disease management in organic apple orchards in Vermont is focused on controlling diseases with sulfur fungicides. The objective of this two year study was to evaluate the target and non-target effects of an organic disease management system containing agricultural biostimulants compared to two sulfur-based systems on foliar and fruit diseases, pest and beneficial arthropods, tree growth, yield and fruit quality on four cultivars, `Ginger Gold', `Honeycrisp' and `Liberty' and `Zestar!'. Trees were arranged in a complete randomized design of five three-tree replications in a certified organic orchard. The two sulfur-based systems differed in the number of applications; in the third …

Top-Down And Bottom-Up Tools For Integrated Pest Management In Northeastern Hop Production, Lily Calderwood

Graduate College Dissertations and Theses

The demand for locally sourced hops from Northeastern microbreweries began the recent resurgence in local hop production. The farming community has increased acreage and improved the quality of hops grown and processed in the Northeast region over the past five years. There was a sharp increase in the number of Northeast hop producers from six in 2009 to over 175 in 2014. Hop growers in the Northeast are new to the crop and have limited experience with pest identification and management. This dissertation encompasses three research projects that were conducted over the 2012-2014 growing seasons. These projects were the first …

Lexical Mechanics: Partitions, Mixtures, And Context, Jake Ryland Williams

Graduate College Dissertations and Theses

Highly structured for efficient communication, natural languages are complex systems. Unlike in their computational cousins, functions and meanings in natural languages are relative, frequently prescribed to symbols through unexpected social processes. Despite grammar and definition, the presence of metaphor can leave unwitting language users "in the dark," so to speak. This is not problematic, but rather an important operational feature of languages, since the lifting of meaning onto higher-order structures allows individuals to compress descriptions of regularly-conveyed information. This compressed terminology, often only appropriate when taken locally (in context), is beneficial in an enormous world of novel experience. However, what …

Traumatic Brain Injury Causes Endothelial Dysfunction In Mesenteric Arteries 24 Hrs After Injury, Ivette Ariela Nunez

Graduate College Dissertations and Theses

Traumatic brain injury (TBI) is the most frequent cause of death in children and young adults in the United States. Besides emergency neurosurgical procedures, there are few medical treatment options to improve recovery in people who have experienced a TBI. Management of patients who survive TBI is complicated by both central nervous system and peripheral systemic effects. The pathophysiology of systemic inflammation and coagulopathy following TBI has been attributed to trauma-induced endothelial cell dysfunction; however, there is little knowledge of the mechanisms by which trauma might impact the functions of the vascular endothelium at sites remote from the injury. The …

A Comparative Analysis Of The Moose Rumen Microbiota And The Pursuit Of Improving Fibrolytic Systems., Suzanne Ishaq Pellegrini

Graduate College Dissertations and Theses

The goal of the work presented herein was to further our understanding of the rumen microbiota and microbiome of wild moose, and to use that understanding to improve other processes. The moose has adapted to eating a diet of woody browse, which is very high in fiber, but low in digestibility due to the complexity of the plant polysaccharides, and the presence of tannins, lignin, and other plant-secondary compounds. Therefore, it was hypothesized that the moose would host novel microorganisms that would be capable of a wide variety of enzymatic functions, such as improved fiber breakdown, metabolism of digestibility-reducing or …

Chemical Composition, Probiotic Survivability And Shelf Life Studies Of Symbiotic Buttermilk, Dong Zhang

Graduate College Dissertations and Theses

Cultured buttermilk is becoming popular as an ingredient for bakery applications and for direct consumption in the U.S.. The objective of this study was to develop a symbiotic cultured buttermilk, containing inulin as a prebiotic and the probiotics Lactobacillus acidophilus and Bifidobacterium spp. The cultured buttermilk was prepared using a commercial mesophilic starter CHN22 (Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Leuconstoc mesenteorides subsp. cremoris, Lactococcus lactis subsp. lactis biovar diacetylactis) and the probiotics. The control buttermilk was prepared using CHN22 and the symbiotic buttermilk were analyzed for chemical composition, probiotics survivability, mold, yeast …

Meckelin Functions In The Guided Movement And Orientation Of Basal Bodies Prior To Duplication In Paramecium Tetraurelia, Tyler August Picariello

Graduate College Dissertations and Theses

Ciliopathies are a group of disorders that arise from ciliary dysfunction. Meckelin (MKS3 or TMEM67) is a conserved transmembrane protein found at the transition zone of ciliated cells. In humans MKS3 is one of 3 genes linked to the ciliopathy Meckel Syndrome. This disease is characterized by occipital meningioencephalocoele, polycystic kidneys, fibrotic changes to the liver, postnatal polydactyly and situs inversus.

Paramecium tetraurelia is a single celled ciliated eukaryote. Its surface is organized of a meshwork of cortical units that run the length of the cell. At the center of the cortical units are either one or two basal bodies. …

Fixed Versus Plastic Partial Migration Of The Aquatic Macroinvertebrate, Mysis Diluviana, In Lake Champlain, Peter Thomas Euclide

Graduate College Dissertations and Theses

Partial migration, whereby populations consist of residents and migrants, is common among migrating organisms. Partial migration of aquatic organisms, however, remains largely under-studied even though many aquatic animals exhibit horizontal and vertical migrations during their lifetime. Macroinvertebrates of the genus Mysis exhibit diel vertical migrations (DVM). Some species have recently been observed to exhibit partial diel migrations where some individuals reside on the bottom throughout the night while others migrate into the water column. To test the hypothesis that individuals are fixed as residents or migrants, we compared demographic information and C and N isotope compositions of M. diluviana caught …

Abscisic Acid And Nitrate Transporter Mtlatd/Nip Signaling In Root And Nodule Development In Medicago Truncatula, Chang Zhang

Graduate College Dissertations and Theses

Abscisic acid (ABA) is a plant hormone that regulates various developmental processes and environmental stress responses. ABA modulates growth of both primary roots and lateral roots, helping to shape root architecture. The lateral root organ defective (latd) mutants, disrupted in the MtLATD/NIP gene, encoding a nitrate transporter, have severe root growth defects that can be rescued by applying ABA. However, the way in which ABA stimulates latd root growth is unclear, and the downstream components of MtLATD/NIP and ABA signaling are completely unknown. To answer these questions, this dissertation focuses on two major potential downstream regulators: Reactive Oxygen Species (ROS) …

Cellular And Molecular Events Regulating Factor V Endocytosis By Megakaryocytes, Jacqueline Michelle Gertz

Graduate College Dissertations and Theses

Platelet- and plasma-derived factor Va are absolutely essential for thrombin generation catalyzed by the prothrombinase complex, a 1:1 stoichiometric complex of the serine protease factor Xa and the nonenzymatic cofactor, factor Va, assembled on an appropriate membrane surface in the presence of calcium ions. Two whole blood pools of the procofactor, factor V, exist: approximately 75% circulates in the plasma as a single chain inactive molecule, while the other 25% resides in platelet α-granules in a partially proteolytically-activated state. Our laboratory demonstrated that the platelet-derived cofactor originates following endocytosis of plasma-derived factor V by megakaryocytes, the platelet precursor cells, via …