Life Sciences Commons^™

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 …

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 …

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 …

Climatic Controls On Organic Matter Decomposition In Boreal Peatlands, Michael J. Philben

Theses and Dissertations

Boreal peatlands currently contain 550 Pg C and are located at high latitudes where mean annual temperatures are expected to increase by as much as 7°C by the end of the century. There is growing concern that warming will stimulate decomposition, transforming peatlands from a sink to a source of atmospheric carbon dioxide and accelerating climate change. A primary goal of this dissertation was to evaluate the effect of climate change on organic matter decomposition in peatlands. This was achieved by developing and employing biochemical tracers to indicate the extent of peat decomposition across a range of naturally occurring climatic …

Methods For Identifying Regions Of Brain Activation Using Fmri Meta-Data, Meredith A. Ray

Theses and Dissertations

Functional neuroimaging is a relatively young discipline within the neurosciences that has led to significant advances in our understanding of the human brain and progress in neuroscientific research related to public health. Accurately identifying activated regions in the brain showing a strong association with an outcome of interest is crucial in terms of disease prediction and prevention. Functional magnetic resonance imaging (fMRI) is the most widely used method for this type of study as it has the ability to measure and identify the location of changes in tissue perfusion, blood oxygenation, and blood volume. In practice, the three-dimensional brain locations …

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 …

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 …

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 …

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 …

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 …

Neodymium Isotopic Signature Of The Deep Western Boundary Current And The Distribution Of Neodymium Isotopes And Concentrations Across Line W, Brian Daniel Duggan

Theses and Dissertations

The capacity of the neodymium (Nd) 143Nd/144Nd ratio to trace modern ocean circulation accurately allows for the assumption that the ratio can also accurately trace paleo ocean circulation. Therefore, a complete understanding of Nd cycling and its effect on the isotopic composition in the oceans is vital. Traditionally, Nd isotopic composition (Nd IC) is considered a conservative property in the open ocean, while coastal and margin environments tend to be dictated by nonconservative exchange processes. However, Nd concentrations ([Nd]) in the open ocean typically display a nutrient like profile, increasing with depth. Such a discrepancy between Nd IC and [Nd] …

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 …

An Optogenetic Brain-Machine Interface For Spatiotemporal Neuromodulation, Ryan Andrew Baumgartner

Theses and Dissertations

Direct neural stimulation has recently become a standard therapy for neurological disorders such as Parkinson's Disease, Essential Tremors, and Dystonia. Currently, deep brain electro-stimulation and neuro-pharmaceutical treatments are the dominant therapeutic options available to the public. As our understanding of brain function and neurological diseases improves, we are able to develop more advanced neuromodulation techniques. These methods could become viable treatment solutions for treating brain dysfunction. Optogenetics, first introduced by a research team led by Karl Deisseroth at Stanford University, has proved to be a versatile technique with remarkable potential to be used in treatments for brain disorders, dysfunction, and …

Phosphorus Recycling By Profunda Quagga Mussels In Lake Michigan, Caroline Mosley

Theses and Dissertations

Quagga mussels (Dreissena rostiformis bugensis) act as ecosystem engineers in the southern basin of Lake Michigan, altering physical habitats and biogeochemical processes. Adapted to cold and oligotrophic conditions, profunda quagga mussels thrive on the soft substrate of deeper depths. At a 55 m site (10,000 mussels m-2) offshore from Milwaukee, WI, profunda mussel biomass (g m-2) was 1/3 of biomass (g m-2) measured at a 10 m comparison site (5,000 mussels m-2). Higher densities but less biomass is due to profunda mussels having less tissue for a given length and the population per m2 comprising of mostly small mussels ( …

Impact Of Gestational Exposure To 2,3,7,8-Tetrachlorodibenzo-P-Dioxin On T Lymphocyte Development, Lori S. Ahrenhoerster

Theses and Dissertations

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitous environmental contaminant and the best characterized agonist of the arylhydrocarbon receptor (AHR), a transcription factor crucial to the detoxification of numerous xenobiotics. Studies in animals show that TCDD is immunosuppressive in adult exposures, and epidemiological studies have found an association between TCDD exposure and hematologic cancers. Additionally, developmental exposure to TCDD has been shown to increase the likelihood of autoimmunity and to impair immune response to later-life infections. The cells of the immune system are all descended from multipotent hematopoietic stem cells (HSCs) that originate in the fetus. This multipotency, defined as the ability to …

Alcohol Use Disorders And An Fmri Stress Task: A Connectivity Analysis, Natasha E. Wright

Theses and Dissertations

Little research has been conducted on neuronal stress processing in individuals

with alcohol dependence (AD). The present study examined neural stress response in AD individuals compared to controls using an fMRI stress task, assessing amygdala

activation and its connectivity to the medial prefrontal cortex (mPFC). Further, the study

analyzed the impact of hormone levels and subjective stress on frontal-limbic

connectivity patterns.

Ten abstinent AD individuals and 11 controls were recruited. Subjects

participated in an fMRI stress task. A region of interest (amygdala) analysis was

conducted using area-under-the-curve. This activation was then examined in a whole brain functional connectivity analysis. Follow-up …

Foot And Ankle Kinematic And Lower Extremity Muscle Activity During Descent From Varying Step Heights, Emily Gerstle

Theses and Dissertations

Ankle injuries are common during activities of daily living, particularly in negotiation of steps. Previous studies examining steps have generally focused on the ankle, knee, or hip and descent of multiple steps. Joint motion within the foot, utilizing a multi-segment foot model, during step descent has not been extensively studied. Although peroneal muscle activity differences have been identified between participants with healthy and unstable ankles during static activities, little is known about peroneal activity during activities of daily living. A better understanding of the foot kinematics and muscle activity in persons with uninjured ankles may help future studies elucidate the …

The Role Of Brain-Synthesized E2 In Hippocampal Learning And Memory Consolidation In Female Mice, Jennifer Tuscher

Theses and Dissertations

The potent estrogen 17beta-Estradiol (E2) plays a critical role in neuroprotection, serving as an important trophic factor for neurons in the hippocampus, basal forebrain, and prefrontal cortex (Brinton, 2001). In the hippocampus, E2 promotes neurogenesis (Tanapat et al., 1999, Prange-Kiel et al., 2006), protects against cell death after ischemic injury (Garcia-Segura et al., 2001, Zhao and Brinton, 2007), and helps maintain spine morphology crucial for synaptic connectivity and memory (Woolley et al., 1990; Gould et al., 1990, Woolley and McEwen, 1992, Li et al., 2004). However, the mechanisms through which E2 promotes synaptic plasticity and enhances memory function are largely …

Novel Protein Secretion And Chitin Utilization Machinery Of Flavobacterium Johnsoniae, Sampada Suresh Kharade

Theses and Dissertations

Flavobacterium johnsoniae, a member of phylum Bacteroidetes, is a gliding bacterium that digests insoluble chitin. A novel protein secretion system, the Type IX secretion system (T9SS), secretes the motility adhesins SprB and RemA and is also required for chitin utilization. In order to understand F. johnsoniae chitin utilization and the role of the T9SS, Fjoh_4555 (chiA) was targeted for analysis. Disruption of chiA resulted in cells that failed to digest chitin and complementation restored this ability. Antisera raised against ChiA were used to characterize its secretion. ChiA was secreted in soluble form by wild-type cells but remained cell-associated in T9SS …

Microvascular Function In Metabolically Healthy Groups Differing In Bmi And Waist Circumference, Nathan R. Earl

Theses and Dissertations

BACKGROUND: Microvascular dysfunction (MD: impaired performance of blood flow, tissue perfusion, blood pressure, etc.) is one of the earliest stages in the progression of various chronic diseases. OBJECTIVE: The aim of this study was to determine if a difference in microvascular function existed between two metabolically healthy groups that differed in BMI and waist circumference. DESIGN: This study employed a causal comparative design, with two groups: I) normal weight (n =14, BMI 28 kg/m2). METHODS: Microvascular function was assessed by measuring skin blood flow (SkBF) using laser Doppler flowmetry during postocclusive reactive hyperemia (PORH). The area under the SkBF time …

An Optimization Method For Estimating Joint Parameters Of The Hip And Knee, Ben Tesch

Theses and Dissertations

Biomechanics, generally speaking, concerns the application of engineeringprinciples to the study of living things. This work is concerned withhuman movement analysis, a subfield of biomechanics, where the methodsof classical mechanics are applied to human movement. This field hascontributed to the general understanding of human movement, and itstechniques are used in the diagnosis and treatment of disease. Centralto the field is the process of measuring human movement. Since classicalmechanics deals with the motion of rigid bodies, and ideal measurementsystem would be able to accurately record the exact pose --- combinedposition and orientation --- of the bones. The techniques that reachthis ideal …

The Hippocampus And Adult Neurogenesis: A Neural Circuit With A Common Role In Behavioral Flexibility And Detailed Memory, Brian Pochinski

Theses and Dissertations

Work with patient H.M. sparked great interest in the role of the hippocampus in learning and memory. Later, the findings that new neurons are born in the adult dentate gyrus (DG) and that they become functionally integrated in neural circuits created new excitement in the field of learning and memory. While there is ample evidence that the hippocampus and adult neurogenesis are involved in learning and memory, similar inconsistencies in both areas have clouded interpretations of their precise role. We propose that studying the role of hippocampus and neurogenesis in the DG must be merged into a more cohesive field …

Interaction Of Rhizobium Sp. Strain Irbg74 With A Legume (Sesbania Cannabina) And A Cereal (Oryza Sativa), Shubhajit Mitra

Theses and Dissertations

Rhizobium sp. IRBG74 (IRBG74) develops a classical nitrogen-fixing symbiosis with the legume Sesbania cannabina and also promotes the growth of rice (Oryza sativa), but not much is known about the rhizobial determinants important for these interactions. We hypothesize that Rhizobium sp. IRBG74 utilizes similar mechanisms to endophytically colonize both legume and cereal hosts. In this study, we analyzed the colonization of rice and S. cannabina using a strain of IRBG74 marked with β-glucuronidase (GUS) and Green Fluorescent Protein (GFP). IRBG74 infected both of the host plants through crack entry under submerged conditions, but showed root hair mediated infection under aerobic …

Gene Regulatory Pathways Driving Central Nervous System Regeneration In Zebrafish, Ishwariya Venkatesh

Theses and Dissertations

Damage to the central nervous system (CNS) circuitry of adult mammals results in permanent disability. In contrast, the ability to regenerate damaged CNS nerves and achieve functional recovery occurs naturally in fish. The ability of fish to successfully regrow damaged CNS nerves is in part a consequence of their ability to re-express key neuronal growth-associated genes/proteins in response to CNS injury. On such protein is Growth-Associated Protein-43 (Gap43), a protein which is highly enriched in axonal growth cones during CNS development and regeneration. Experiments conducted in mammals have demonstrated that ectopic expression of GAP-43 improves axonal re-growth after injury. Using …

Cellular Zinc Trafficking: The Zinc Proteome And Its Reactions With Cadmium, Mohammad Ali Namdarghanbari

Theses and Dissertations

Metals play a crucial role in living systems. Iron, zinc, copper, molybdenum, and manganese are involved in many essential biological activities. Among transition metals, zinc after iron is the most abundant transition metal in the human body and the most abundant in the brain. It exists in more than 3000 proteins, which comprise about 10% of the human proteome. Zn2+ dyshomeostasis is associated with chronic diseases such as metabolic syndrome, diabetes and related complications, bone loss, growth retardation in young children, and neurological and behavioral problems. Despite a good knowledge obtained for metabolism of some metal ions such as copper, …

Landscape Genetics Of The American Badger: Understanding Challenges In Elusive Species, Elizabeth Marie Kierepka

Theses and Dissertations

American badgers are one of the most poorly understood carnivores in North America due to their highly elusive, semifossorial lifestyle. To complicate understanding their biology further, badgers possess life history characteristics that predict radically different responses to habitat heterogeneity. In particular, they are considered grassland specialists, so their movement and population viability could be highly dependent on grassland habitats. Badgers are also highly mobile, which suggests they experience high gene flow. Predicting how these life history traits impact gene flow, however, is difficult based on the high diversity in responses to landscape heterogeneity among carnivores. To assess how landscape heterogeneity …

Part I: Synthesis And Biological Evaluations Of Potent Class L Selective Histone Deacetylase Inhibitors Part Ii: Aqueous Complexes For Efficient Sizebased Separation Of Americium From Curium Part Iii: Designing Strong Chiral Bronsted Acids And Their Application For Oxaxinanones Derivatization And The Aza-Henry Reaction, Joseph Steve Ulicki

Theses and Dissertations

PART I: SYNTHESIS AND BIOLOGICAL EVALUATIONS OF POTENT CLASS l SELECTIVE HISTONE DEACETYLASE INHIBITORS

Histone deacetylase inhibitors (HDACi) have found a wide variety of medicinal uses and are most noted for their specific apoptotic action towards cancer cells1. Several hydroxamates and tetrapeptides HDACi have since been moved on to phase 1 and 2 clinical trials, with FK228 & SAHA having already been approved for treatment of advanced cutaneous T-cell lymphoma (CTCL). FK228 & SAHA are pan-HDACi which d compounds describes the unselective inhibition for any of the 11 Zn2+-dependent HDAC isoforms. Research in the past five years, has shifted towards …

The Impacts Of Feral Horses On The Use Of Water By Pronghorn On The Sheldon National Wildlife Refuge, Nevada, Amy Marie Gooch

Theses and Dissertations

Feral horses occupy 31.6 million acres throughout western North America. Feral horses share similar habitats with a wide range of animal species, including pronghorn. Since horses are larger and often more aggressive than other animals of this region, they are generally socially dominant over all other native ungulate species. Pronghorn share water sources with horses in areas where both occur. In situations where horses exclude pronghorn from water, pronghorn fitness may be impaired, especially during the hottest months of the year when water is limited. The purpose of this study was to investigate interference competition between pronghorn and feral horses …

Targeted Sequencing Of Plant Genomes , Mark D. Huynh

Theses and Dissertations

Next-generation sequencing (NGS) has revolutionized the field of genetics by providing a means for fast and relatively affordable sequencing. With the advancement of NGS, whole- genome sequencing (WGS) has become more commonplace. However, sequencing an entire genome is still not cost effective or even beneficial in all cases. In studies that do not require a whole-genome survey, WGS yields lower sequencing depth and sequencing of uninformative loci. Targeted sequencing utilizes the speed and low cost of NGS while providing deeper coverage for desired loci. This thesis applies targeted sequencing to the genomes of two different, non-model plants, Artemisia tridentate (sagebrush) …