Life Sciences Commons^™

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 …

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 …

Oligomerization Of The Sterile-2 G-Protein Coupled Receptor In Yeast Cells In The Presence And Absence Of Alpha-Factor Pheromone Using Fluorescence Spectroscopy And Forster Resonance Energy Transfer Analysis, Joel David Paprocki

Theses and Dissertations

G-protein-coupled receptors (GPCRs) are the largest family of receptors that respond to a wide variety of extracellular stimuli, including molecular ligands such as odorants, neurotransmitters, and hormones, as well as physical agents sigh as light and pressure. The stimulation event results in initiating conformational changes in the structure of the receptor, which further results in the release of the heterotrimeric G-protein; the latter has a variety of functions within signaling pathways in cellular biology. The GPCR explored in this investigation is the Sterile 2 α-factor receptor (Ste2), whose natural function is that of a yeast mating pheromone receptor. Its natural …

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 …

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 …

Spatial Heterogeneity Of Ecosystem Metabolism In A Shallow Wetland, Daniel Riley Rackliffe

Theses and Dissertations

Spatial heterogeneity in ecosystem metabolism may play a critical role in determining ecosystem functions. Variation in ecosystem metabolism between macrophyte patches in shallow wetlands at the extremes of freshwater habitats has not been investigated. We estimated ecosystem metabolism in mesocosms containing different macrophytes using 24-hour oxygen curves to test our hypotheses: (1) net aquatic production (NAP) during spring and summer would be similar among algal patches (metaphyton and Chara), (2) NAP in algal patches would be greater than patches dominated by the vascular plant Potamogeton foliosus, (3) heterotrophy and anaerobiosis would be greatest in patches dominated by Lemna, and (4) …

A Molecular Phylogeny Of Lampyridae With Insight Into Visual And Bioluminescent Evolution, Gavin Jon Martin

Theses and Dissertations

Fireflies are some of the most captivating organisms on the planet. Because of this, they have a rich history of study, especially concerning their bioluminescent and visual behavior. Among insects, opsin copy number variation has been shown to be quite diverse. However, within the beetles, very little work on opsins has been conducted. Here we look at the visual system of fireflies (Coleoptera: Lampyridae), which offer an elegant system in which to study visual evolution as it relates to their behavior and broader ecology. They are the best-known case of a terrestrial organism that communicates through the use bioluminescence. The …

Variation In Resource Utilization And Cost Of Reproduction For Two Burying Beetle Species, Peter J. Meyers

Theses and Dissertations

The cost of reproduction hypothesis suggests that allocation into current reproduction constrains future reproduction. How organisms accrue reproductive costs may differ between species and with varying levels of resource quality. Burying beetles are model organisms for testing for the cost of reproduction because of their unique natural history; beetles utilize small vertebrate carcasses for reproduction and they and their offspring feed exclusively on these discrete resources. Burying beetles also can utilize a large range of carcass sizes for reproduction. We tested for the cost of reproduction in two species of burying beetles, Nicrophorus marginatus and Nicrophorus guttula found in Central …

The Interaction Of Aeolian And Fluvial Processes In Dry Washes On The Colorado Plateau, Usa, Beau Jensen Walker

Theses and Dissertations

In the past decade there has been a call for integrated studies that examine the interaction of fluvial and aeolian processes (Belnap et al., 2011; Bullard and Livingstone, 2002). In this study, we examined the role of land-use, weather, and soil type on the flux of aeolian material into dry washes on the Colorado Plateau in central Utah, USA, and western Colorado, USA. Our goal was to quantify the impact of individual deposition and erosion events by correlating weather and land-use data with a combination of measurement methods including dust collection via dust traps, GPS surveying, and close-range photogrammetry. Our …

Understanding The Diversification Of Central American Freshwater Fishes Using Comparative Phylogeography And Species Delimitation, Justin C. Bagley

Theses and Dissertations

Phylogeography and molecular phylogenetics have proven remarkably useful for understanding the patterns and processes influencing historical diversification of biotic lineages at and below the species level, as well as delimiting morphologically cryptic species. In this dissertation, I used an integrative approach coupling comparative phylogeography and coalescent-based species delimitation to improve our understanding of the biogeography and species limits of Central American freshwater fishes. In Chapter 1, I conducted a literature review of the contributions of phylogeography to understanding the origins and maintenance of lower Central American biodiversity, in light of the geological and ecological setting. I highlighted emerging phylogeographic patterns, …

Role Of Epistasis In Alzheimer's Disease Genetics, Mark T. Ebbert

Theses and Dissertations

Alzheimer's disease is a complex neurodegenerative disease whose basic etiology and genetic structure remains elusive, despite decades of intensive investigation. To date, the significant genetic markers identified have no obvious functional effects, and are unlikely to play a role in Alzheimer's disease etiology, themselves. These markers are likely linked to other genetic variations, rare or common. Regardless of what causal mutations are found, research has demonstrated that no single gene determines Alzheimer's disease development and progression. It is clear that Alzheimer's disease development and progression are based on a set of interactions between genes and environmental variables. This dissertation focuses …

Generality Of The Terminal Investment Hypothesis: Effects Of Extrinsic Mortality And Resource Availability On Age-Related Reproductive Investment, Allystair Jones

Theses and Dissertations

A central question in life history theory is, what combination of traits and behaviors will lead to the highest reproductive success throughout a lifetime. The trade-off between current and future reproduction is central to the lifetime reproductive success of an organism. If there is a cost to reproduction, then allocation of energy to current reproduction will come at a cost to future reproduction. We expect young individuals to favor future reproduction over current reproduction and that balance shifts to current reproduction as they age (i.e. terminal investment hypothesis). However, how this transition from an emphasis on future reproduction to emphasis …

Metamorphosis Of Limulus Polyphemus Trilobite Larvae: Role Of Chemical And Structural Cues, Competency, And The Cost Of Delayed Metamorphosis, Stephanie Marie Kronstadt

Theses and Dissertations

Many marine and estuarine arthropods exhibit complex life cycles that include planktonic larval stages and benthic juvenile and adult phases. Chemical and structural cues associated with juvenile habitats often induce settlement and metamorphosis, thereby shortening the duration of the larval phase. These cues can trigger metamorphosis only after larvae reach competency, or developmental maturity. The point at which larvae reach this competency period and the ability to retain competency is highly species specific. Once competency is attained, a decrease in the time to metamorphosis (TTM) can decrease dispersal potential but may increase the chance of settling in a suitable habitat. …

Small Mammals Matter? Linking Plant Invasion, Biotic Resistance, And Climate Change In Post-Fire Plant Communities, Rory Charles O'Connor

Theses and Dissertations

The introduction and establishment of exotic species can profoundly alter ecosystems. Two exotic species drastically changing the landscape of deserts in western North America are Bromus tectorum L. and Bromus rubens L. Through the buildup of biomass and slow decomposition rates in deserts these two exotic annual grasses can alter fire regimes that change the plant and animal community dynamics in the ecosystems. To better understand the ecological mechanisms that could restrict or alter the patterns of invasive plant establishment we established a replicated full factorial experiment in the Great Basin and Mojave Desert. The combinations of factors being manipulated …

An Investigation Of Mitochondrial Bioenergetics And The Turnover Of Succinated Proteins In The Adipocyte During Diabetes, Ross Tanis

Theses and Dissertations

We previously identified the chemical modification S-(2-succino)cysteine (2SC), which is formed when the Krebs cycle metabolite fumarate reacts with protein cysteine residues, also termed protein succination. Protein succination is increased in the adipose tissue of ob/ob and db/db mice in vivo and in 3T3-L1 adipocytes grown in high glucose in vitro. The increase in 2SC in the 3T3-L1 adipocyte occurs as a direct result of glucotoxicity and increased mitochondrial stress. We have shown that uncoupling agents, which lower mitochondrial stress, prevent the increase in succinated proteins.

In this study we examined the relationship between increased succination and mitochondrial bioenergetics in …

Mechanical Properties Of Diet And Its Effect On Oral Health, Varsha Kapoor

Theses and Dissertations

The predominant diet fed to captive carnivores consists of ground meat formulated to provide full nutritional requirements. However, this ground meat diet completely lacks the mechanical properties such as toughness, hardness and stiffness of the foods the animals would eat in the wild. The goal of this research was to evaluate the effect of mechanical properties of diet on oral health by comparing prevalence of periodontal disease and calculus accumulation in wild and captive felids. One-way ANOVA analysis of variance indicated that these differences are statistically significant (P

Role Of Apelin And Endothelin Systems In The Pain Associated With Sickle Cell Disease, Terika Smith

Theses and Dissertations

Sickle cell disease (SCD) is a common genetic blood disorders that is characterized by painful vaso-occlusive episodes (VOEs), which are the major cause of hospitalizations for these patients. One of the mechanisms that may contribute to the development of painful VOEs is the imbalance between vasoconstrictors and vasodilators. This thesis focuses on the vasoconstrictors endothelin-1 (ET-1), which is elevated during VOEs and is pro-nociceptive, and angiotensin II (Ang II) and the vasodilator apelin, which has anti-nociceptive properties. This thesis tested two hypotheses: 1) an imbalance between the vasoconstrictive and pro-nociceptive systems and vasodilatory and anti-nociceptive systems contributes to pain in …

Differential Expression Of Snmps And Their Underlying Transcriptional Regulation In Chemosensory Pathways Of Drosophila, Richard A. Fandino

Theses and Dissertations

Insects possess complex and diverse chemosensory pathways which have specific phenotypes determined by the regulated expression of specific combinations of genes. While many of these genes (e.g. ORs and GRs) have very narrow expression patterns, associating with only a limited number of chemosensory sensilla, SNMPs show a very broad expression pattern. In Drosophila, SNMP1 and SNMP2 associate with the majority of olfactory and gustatory sensilla, but express in different cell types. In olfactory sensilla, SNMP1 and SNMP2 associate with trichoid or coeloconic neurons respectively, and both additionally express in a variety of sensilla support cells; in gustatory sensilla, SNMP2 expresses …

Functional Characterization Of Fro4 And Fro5: Two Members Of The Ferric Chelate Reductase Family Of Arabidopsis, Grandon Thomas Wilson

Theses and Dissertations

Iron (Fe) is the fourth most abundant element within the earth’s crust and is an essential micronutrient for plants and animals. Fe plays key roles in photosynthesis, respiration and chlorophyll biosynthesis in plants and in hemoglobin in animals. Like Fe, copper (Cu) is also an important micronutrient in plants and is needed for photosynthesis and respiration, especially in the important copper-containing protein plastocyanin. Copper also is important in scavenging reactive oxygen species and ethylene perception. The reduction of Fe3+ to Fe2+ at the root surface of Arabidopsis thaliana during times of Fe deficiency has been a well-characterized process; however, reduction …

Genetic Background Influences Behavior And Responses To Epigenetic Changes Induced By A Methyl-Donor Diet, Kimberly R. Shorter

Theses and Dissertations

With recent strides in epigenetics, mainstream media informs the public that we can “beat our genes” by, for instance, changing our diet. Genetics, however, still plays a role in phenotype. Folate and other methyl-donor pathway components are widely supplemented due to their ability to prevent neural tube defects during prenatal development. In addition to vitamins, these compounds are also added to commercial flour, energy drinks, and other supplements. Several lines of evidence suggest that these supplements act through epigenetic mechanisms, including altering DNA methylation. Increasing evidence suggests potential deleterious effects of excessive folate. Given the benefits of these compounds, risk …

Utilizing Next Generation Sequencing To Generate Bacterial Genomic Sequences For Evolutionary Analysis, Derrick C. Scott

Theses and Dissertations

Many important questions in the field of prokaryotic biology cannot be answered due to the low availability of sequenced and finished genomes. Recent improvements in technology and decreases in price have made the ambition of de novo bacterial genomic sequencing a reality for a wide range of researchers. However, with the advancement of sequencing technology comes the need for an evaluation to determine the most reliable bioinformatics methods in generating a complete and accurate assembly. Biases inherent in the sequencing technology and GC-rich genomes complicate genome assemblies. Here, we sequenced bacterial strains from the GC-rich Caulobacter genus and the closely …