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Epigenetic Regulation Of Nuclear Hormone Receptor Dax-1, Michael B. Heskett

Master's Theses

DAX-1 (NR0B1) is an orphan nuclear receptor that plays a key role in the development and maintenance of steroidogenic tissue in mammals. Dax-1 is also expressed in mouse embryonic stem (ES) cells and is required to maintain pluripotency. Duplication of the X-chromosome in the region containing the NR0B1 gene results in sex reversal, and mutations in NR0B1 cause adrenal hypoplasia congenita. DAX-1 has been observed to act as a corepressor of other nuclear receptors including androgen receptor (AR), estrogen receptor (ER), and steroidogenic factor 1 (SF-1). In addition to pluripotent ES cells, DAX-1 is primarily expressed in select tissues of …

Mechanisms Of Condition-Specific Regulation Of Mrna Stability By Puf Proteins: From Yeast To Humans, Joseph Russo

Dissertations

RNA binding proteins regulate mRNA decay and translation, two key steps in the control of gene expression in cells. Controlling mRNA metabolism allows cells to respond rapidly to altering conditions by utilizing already available mRNA, bypassing the wait for newly transcribed mRNA. The Puf family of RNA binding proteins bind specific mRNAs through interactions with sequences located in the 3’ untranslated region (UTR). Puf proteins are conserved throughout eukaryotes and have diverse roles including stem cell maintenance, neuronal development, stress response and organelle biogenesis. In Saccharomyces cerevisiae, Puf proteins are conditionally regulated in response to the cells metabolic. Specifically, in …

A Description Of Tolerance To Apical Meristem Damage In Wild Populations Of Arabidopsis Thaliana And Its Genetic Basis, Justin Dalrymple

Biology Theses

Since plants cannot actively avoid herbivory, they rely on two primary strategies to maintain their fitness in the face of herbivore pressure: resistance—the deterrence of herbivory via physical and chemical means—and tolerance—recuperation of aboveground mass after herbivory. Although diverse groups have been shown to be tolerant to herbivory, mechanisms of tolerance are not yet well known. There is also very little known about the ecological relevance of tolerance strategies in wild populations. In Arabidopsis thaliana, the apical meristem suppresses growth of axillary meristems to a high degree under normal conditions, but a number of axillary meristemswill grow after apical meristem …

Compositional Traits In Sorghum Bicolor Characterized By Transcriptome, Ionome And Genome-Wide Association Analysis, Nadia Shakoor

Theses and Dissertations

To address the challenge of global mineral malnutrition, current biofortification research in crop plants aims to improve mineral concentration and micronutrient bioavailablity via genetic and traditional breeding methods. Many staple food crops are also used as biofuels, and the chemical and mineral composition of these energy crops directly affect biomass quality and subsequent energy output. Identification of genes and QTL that impact mineral and compositional traits in the grain and biomass of major cereals, including sorghum, is fundamental to developing breeding and selection methods aimed at increasing bioavailable minerals and improving biofuel suitability and seed nutritional quality. A combinatorial strategy …

Marine Population Connectivity: Range Boundaries And Climate Change, Rhiannon Leigh Rognstad

Theses and Dissertations

Population connectivity, particularly in open systems, is an important metric for understanding population-level processes on both ecological and evolutionary timescales. In coastal marine systems, adults are typically sedentary and dispersal occurs primarily during a larval stage when individuals are transported in ocean currents. Because coastal marine populations exist as networks of interconnected subpopulations, variation in the magnitude and extent of population connectivity can have profound effects on population dynamics and species distribution limits. Connectivity is a complex process, affected by a multitude of factors, including adult inputs and physical dispersal, which operate at multiple scales and may interact. This dissertation …

Determining The Critical Window Of Influence Of Pcb Perinatally On Behavioral And Hormonal Development In Sprague-Dawley Rat Pups, Natalie Sommerville, Lee A. Meserve, Howard C. Cromwell

Honors Projects

Polychlorinated biphenyls (PCB) had widespread use in the United States in commercial manufacturing in the United States until the late 1970s. Even though they were banned, measurable amounts can still be found in the environment and food sources. PCB has known effects on altering hormone development and behavior in the species Rattus norvegicus. To determine the most crucial developmental time of exposure to PCB in Sprague-Dawley rat pups, rat pups were exposed to PCB at differing weeks of either gestation period or the first postnatal week. Behavioral tests were performed for the different rat pups, as well as blood …

Thermal Ecology And Physiology Of An Intertidal Predator-Prey System: Pisaster Ochraceus And Mytilus Californianus, Cristian J. Monaco

Theses and Dissertations

Untangling natural systems’ complexity requires understanding the mechanisms responsible for organisms’ responses to environmental change. Recently, significant advances have been made by recognizing the relevance of direct and indirect effects, which take place when multiple biotic and abiotic factors influence each other. I examined potential direct effects of environmental variables on a predator-prey interaction, as well as potential indirect effects of these variables on the interaction itself. I placed emphasis on behavioral and physiological adaptations, which would potentially contribute/modify these effects. My study system was comprised of a rocky intertidal keystone predator, the sea star Pisaster ochraceus, and its main …

The Roles Of Gsk-3ss And Apc In Cytoplasmic Dynein Regulation, Feng Gao

Theses and Dissertations

Dynein is a microtubule minus-end directed molecular motor, participating in a broad range of cellular functions, such as organelle transport, cell migration and mitosis. Dynein dysfunction is linked to many diseases including ALS, schizophrenia, Alzheimer’s disease, Parkinson’s disease and cancer. The mechanism of dynein regulation is largely unknown. We have provided evidence that glycogen synthase kinase 3β (GSK-3β) directly regulates dynein in both neurons and non-neuronal cells. GSK-3β interacts with and phosphorylates dynein in vitro. Dynein phosphorylation by GSK-3β reduces its interaction with Ndel1, a regulator contributing to dynein force generation. Dynein motility is stimulated both by pharmacological GSK-3β inhibitors …

Global Climate Change And The Southern Ocean: How Antarctic Fishes Physiologically Respond To A Changing Environment From The Cellular To The Organismal Level, Laura A. Enzor

Theses and Dissertations

Studies have projected that future changes in sea surface temperature and pCO2 levels will impact higher latitudes to a greater extent than in temperate regions. For notothenioid fishes of the Southern Ocean, evolution in extremely stable, cold waters has resulted in several adaptations which have left these fishes poorly prepared for global climate change. I have analyzed the metabolic and cellular response of Trematomus bernacchii, Pagothenia borchgrevinki and Trematomus newnesi to a long-term, multi-stressor scenario relevant to the predicted changes in the Southern Ocean. By combining whole animal respirometry with cellular level analysis of energy allocation, osmoregulatory mechanisms and cellular …

Molecular Mechanisms Of Gap Junction Regulation By The E3 Ubiquitin Ligase Wwp1, Measho Hagos Abreha

Theses and Dissertations

Ubiquitylation is a post-translational modification that influences a wide variety of cellular processes including protein degradation, protein subcellular localization, cell cycle progression, transcription, and DNA damage repair. Covalent attachment of the small ubiquitin molecule to a target protein involves the sequential action of three enzymes (E1, E2, and E3). In this process, substrate specificity is conferred by the E3 ligase. Our work has focused on the function of one such E3 ubiquitin ligase, WWP1. Known targets of WWP1 include cell cycle proteins, tumor suppressors, and transcription factors that promote differentiation of mesenchymal stem cells to the osteoid lineage. Recently, we …

The Role Of Lis1 In Adult Mammalian System, Xu Gao

Theses and Dissertations

Lis1 haploinsufficiency in humans results in a “smooth brain” phenotype called lissencephaly, and also causes severe cognitive and motor impairments and epilepsy. Seizure severity and frequency typically worsens with time; patients often die within the first decade due to seizure-induced aspiration and pneumonia. Various mouse models have been used to examine the role of Lis1 during brain development, and it is clear that Lis1 regulates a microtubule motor, cytoplasmic dynein. Intriguingly, Lis1 expression remains high in adult brains indicating that it plays a role in mature systems. Indeed, our group found that Lis1 and several related proteins regulate dynein-dependent axon …

Understanding The Evolutionary History Of Biochemical Innovation, Madeline Opal St. Julien

Theses and Dissertations

The serine protease (SP) gene family is an ecologically important gene family because of observed involvement in innate immunity, digestive processes, and embryological development of arthropods. In the past decade, all genes of the serine protease family have been classified in a number of arthropods, with the exception of crustacean. Possible evolutionary mechanisms have been observed based off of varying selectional pressures acting on recent SP expansions in respect to varying diets. Daphnia is the first crustacean to have its genome sequenced, and their genomes were analyzed in this study to elucidate the expansion and divergence of the SP gene …

Ferric Reductases And Transporters That Contribute To Mitochondrial Iron Homeostasis, Anshika Jain

Theses and Dissertations

Iron (Fe) is the fourth most abundant element in the Earth’s crust, yet the availability of Fe to plants is often limited. This is because in most soil types, Fe precipitates as ferric-oxyhydroxy complexes, making it unavailable for uptake by plants. While the mechanisms involved in Fe uptake from the soil are relatively well understood, the mechanisms involved in its further distribution to the aerial portion of the plant and to subcellular compartments are not fully understood. During Fe deprivation, plants up-regulate root Fe acquisition machinery. How plants sense Fe deprivation and tie the Fe status of the plant to …

Diversity, Genetics, And Health Benefits Of Sorghum Grain, Davina Rhodes

Theses and Dissertations

Staple cereal crops provide the majority of nutrients to the world's population, and thus, can significantly impact human nutrition and health. Phenotypic and genetic diversity within a crop can be useful for biofortification and crop improvement, but quantitative phenotyping is needed to identify varieties with high or low concentrations of a nutrient of interest, and to identify alleles responsible for quantitative trait variation of the nutrient. Sorghum [Sorghum bicolor (L.) Moench] is a diverse and widely adapted cereal crop that provides food for more than 500 million people in sub-Saharan Africa and Asia, and is becoming increasingly popular in specialty …

An Essential Role For Self-Pmhc Throughout The Life Of A Cd4 T Cell: Contributions In The Thymus And Periphery, Stephanie Rodriguez

Arts & Sciences Electronic Theses and Dissertations

It is well established that self-peptide Major Histocompatibility Complexes (hereafter self-pMHC) are essential for the development of a broad repertoire of mature, self-tolerant CD4 and CD8 T cells. Despite clear knowledge that the pool of self-ligands is critical for positive and negative selection, the exact kinetics and dynamic nature of thymocyte interaction with self-pMHC class II (self-pMHCII) bearing antigen-presenting cells (APCs) during development is still largely a mystery. The enigmatic nature of selecting self-pMHC is not unique to the thymic environment; increasingly evident is the dependence of peripheral T cells on extra-thymic self-pMHC expression, specifically selecting self-pMHC, for their homeostatic …

Origin Of Maternal Age Effect In Congenital Heart Disease Risk For Offspring, Claire Elaine Schulkey

Arts & Sciences Electronic Theses and Dissertations

Increasing maternal age is widely acknowledged to lead to greater likelihood of pregnancy complications and congenital abnormalities, but the basis of this effect has not been well studied. Often dismissed as the product of oocyte ageing, the mechanistic basis of this maternal age effect is likely more complex.

Congenital heart disease is a classic complex disease with multiple genetic and environmental modifiers, including maternal age. Maternal ageing is a known risk-factor in humans, and has been shown to exist in an Nkx2-5 haploinsufficient mouse model for the disease. This mouse model's maternal age risk is dependent upon strain background, with …

The Influence Of Metacommunity Size On Species Diversity Across Spatial Scales, Lauren Woods

Arts & Sciences Electronic Theses and Dissertations

This dissertation explores the influence of metacommunity size and landscape level processes, such as dispersal, on species diversity. A metacommunity is a group of local communities, or patches, connected by dispersal, and metacommunity size can be defined as the number of discrete local patches within a metacommunity. In chapter 1, I developed a framework to predict the effects of habitat destruction, or a reduction in metacommunity size, on the species richness of local patches of different sizes by integrating metacommunity theory with the equilibrium theory of island biogeography. The effect of metacommunity size on species richness in small and large …

Modulation Of Nmda Receptor Activity During Physiological And Pathophysiological Events, Christine Marie Emnett

Arts & Sciences Electronic Theses and Dissertations

N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors that serve crucial signaling and neurotrophic functions throughout the central nervous system. Both hyperfunction and hypofunction of NMDARs are associated with neurological and neuropsychiatric conditions. Thus, both positive and negative pharmacological NMDAR modulators are of clinical interest as treatments. Understanding drug mechanisms could lead to more rational drug design. Memantine and ketamine are NMDAR open channel blockers that exhibit similar pharmacodynamics at NMDARs but have different clinical uses. Memantine improves cognitive decline during Alzheimer's disease. Ketamine is an anesthetic and analgesic with psychotomimetic effects, but it is also a rapid acting and long-lived …

Evolution Of Ecological Dominance Of Yeast Species In High-Sugar Environments, Kathryn Marie Williams

Arts & Sciences Electronic Theses and Dissertations

Two challenging goals of evolutionary biology are to understand how evolutionary innovations evolve and how they contribute to the success of lineages. Evolutionary innovations may arise following whole genome duplication (WGD) events and they are suspected to contribute to the success of lineages by creating ecological opportunity. However, direct evidence for duplicated genes involved in evolutionary innovations remains rare, and the relationship between evolutionary innovations and the success of lineages may be very complex. In this study, I explore the relationship of evolutionary innovation, WGD, and the ecological dominance of yeast species in high-sugar environments. In budding yeast, a major …

Characterizing The Fitness Landscapes Of Gut Symbionts In Defined Community And Diet Contexts, Meng Wu

Arts & Sciences Electronic Theses and Dissertations

A species' niche is the description of all the environmental conditions required to permit a population of that species to persist, including the effects of the population on those conditions. This definition includes the species' resource requirements, as well as stress tolerances and interactions with other species acting as competitors, predators, parasites, and mutualists. The human gut microbiota serves as a microbial `metabolic organ' tasked in part with the biotransformation of many components of our diet. Relatively little is known about the factors that allow members of the human gut microbiota to persist in a habitat that experiences marked changes …

Characterization Of Vibrio Vulnificus Strains Using Phenotypic And Genotypic Assays, James Conrad

Masters Theses, 2010-2019

In this study 143 V. vulnificus isolates of clinical and environmental origin, were examined for growth on differential media, identified to species and tested for antibiotic resistance. A multiplex PCR was created and optimized, and phylogenetic analysis was conducted. The first objective was to compare phenotypic methods to identify V. vulnificus. Colony colors of confirmed V. vulnificus isolates on selective media (Vibrio vulnificus agar, thiosulfate citrate bilesalts sucrose agar, CHROMAgar Vibrio (CAV), and colistin polymyxin B cellobiose agar), mostly matched those characteristic of V. vulnificus. To test the ability of these media to select for V. vulnificus, new presumptive V. …

Examining The Role Of Dax-1 In Regulation Of Cell Proliferation In Human Breast Cells, Amy E. Scandurra

Master's Theses

DAX-1 is a member of the Nuclear Hormone Receptor superfamily and acts as a transcriptional repressor. DAX-1 plays an important role in the development of adrenal and gonadal tissues. In addition to its role in normal cell development and differentiation, DAX-1 appears to have some influence on the progression of cancer. This work aims to examine the role of DAX-1 in regulation of proliferation in breast cancer. In our study, we have expressed DAX-1 in a DAX-1 deficient breast cancer cell line as well as knocked down DAX-1 expression in normal DAX-1 positive breast cells. Through these experiments, we were …

Wildwood/Kraemer Lake County Park Observational Study: The Effects Of Fragmentation On Old-Growth Forest Species, Rhonda H. Zimmerman

Culminating Projects in Biology

Habitat fragmentation generates forest fragments with increased ratio of "edge". This "edge effect" alters the natural community. Old growth forests support deep forest communities which rely on the closed canopy for survival, often indicators of healthy old growth communities. Putative old growth forest patches were identified in Wildwood Park and St. John’s Arboretum/University. One study objective was to collect baseline data on flora and fauna in Wildwood to confirm the presence of old-growth patches. The main ecological goal of the study was to determine if bird and plant communities exhibited patterns consistent with the operating assumption of 50 acre old-growth …

Using Avifauna To Access The Functional Success Of The Restored Beaver Creek Wetlands Near Cave Run Lake, Menifee County, Kentucky, Brian D. Wulker

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Brian D. Wulker on December 1, 2014.

Fern Community Reassembly In Secondary Forests Of Puerto Rico: Predictors, Complexity, And Niche Model Assessment, Thomas J. Schmidt

Masters Theses

Approximately 94% of Puerto Rico’s forests were converted into agricultural systems by 1950. Since then, extensive abandonment of agricultural land has resulted in a considerable amount of forest regeneration throughout the main island. Ferns are a major non-woody component of oceanic, tropical island forests comprising up to seventy percent of the flora. Consequently, the composition and community structure of ferns may be indicative of the relative richness of these secondary forests. I used Maximum Entropy (Maxent), a widely-used mathematical tool for distinguishing suitable versus unsuitable fern niche space, along with ENMTools, a tool that assists Maxent with proper model selection, …

Comparison Of Movement Patterns In Captive-Released Eastern Hellbenders (Cryptobranchus Alleganiensis Alleganiensis) Using Three Different Release Methods, Julie A. Boerner

Biology Theses

Eastern hellbender (Cryptobranchus alleganiensis alleganiensis) population size has declined throughout much of its range. Previous captive-release headstarting programs have resulted in minimal success, presumably due to movement of captive-released animals away from the release site. This study aimed to increase the success of hellbender headstarting programs by assessing the effectiveness of three release methods. Releases were conducted in two stream sites within the Allegheny River drainage. Streams were similar; however stream A contained a higher boulder density. In each site, three salamanders were placed individually in cages, three salamanders were placed individually in nest boxes with the entrance …

Parallel Adaptation Of Cd4 In Siv-Endemic Gorilla And Pan Lineages, Katie E. Brown

Biological Sciences

The simian immunodeficiency virus (SIV) is homologous to the human immunodeficiency virus (HIV), and naturally infects chimpanzees and gorillas in the wild. Some African primate species appear to have evolved resistance to SIV, in that the virus no longer is found in the species or, if infected, individuals within the species show no serious symptoms of simian AIDS (SAIDS). In contrast, Asian primate species do not appear to naturally harbor SIV and, like humans, often progress to AIDS following infection. CD4 is the primary T cell receptor that SIV/HIV interacts with to infect host T cells. Domain 1 (D1) of …

Genetic Structure Of Yellow Perch Populations In Coastal Areas Of Eastern Lake Michigan, Jessica N. Wesolek

Masters Theses

Genetic population substructure is often overlooked because of discontinuities between management and actual population structure as in the case of yellow perch, an ecologically and economically important indigenous fish species in the Laurentian Great Lakes. A knowledge gaps pertaining to the natural history of yellow perch relates to the biological connectivity between nearshore Lake Michigan and drowned river mouth (DRM) lakes, where it remains unclear whether resident yellow perch from Lake Michigan use DRM lakes for spawning or whether DRM lakes contribute to nearshore yellow perch populations in Lake Michigan. I used DNA fingerprinting (genotyping) to explore biological connectivity between …

Structural Comparison Of Arctic Plant Communities Across The Landscape And With Experimental Warming In Northern Alaska, Jessica L. Gregory

Masters Theses

Understanding vegetation change is central to forecasting the impacts of climate change. Percent cover, determined from a point frame method, is commonly used to monitor vegetation change. Cover is influenced by canopy structure which may change with the size (growth) or number (density) of individual plants. The overarching objective of this project was to document the relationship between vegetation cover and traits representing plant growth and density and determine if these relationships changed with warming. We used regressions and analysis of covariance to detect which of several traits was most strongly related to cover in vegetation at a wet and …

An Exploration Of Cell Cycle Regulation In Arabidopsis Thaliana Trichomes, Ashley Willis

Honors Theses

No abstract provided.