Digital Commons Network^™

Steminism: Analyzing Factors That Improve Retention Of Women In Stem, Kira Carter, Jane Kelley, Jason Vasser-Elong, Rc Patterson

Dissertations

Our co-authored research ‘Steminism: Analyzing Factors That Improve Retention for Women as STEM Majors’ analyzed factors that contributed to the retention of women in science, technology, engineering, and mathematics (STEM) programs at Missouri University of Science & Technology (Missouri S&T). Women make up half of the US population, and while careers in (STEM) are an integral part of the US economy, women are underrepresented in these career fields. The purpose of our dissertation is to address the underrepresentation of women in STEM majors. Our methodology included homogeneous sampling to collect qualitative data. More specifically, we consulted with academic advisors and …

Binding Interactions Of Biologically Relevant Molecules Studied Using Surface-Modified And Nanostructured Surfaces, Palak Sondhi

Dissertations

This research focuses on the field of surface nanobioscience, wherein different nanosurfaces that will be used as working electrodes in the electrochemical cell are manufactured and surface modified to understand the critical binding interactions between biologically significant molecules like proteins, carbohydrates, small drug molecules, and glycoproteins. This research is essential if we are to determine whether a synthetic molecule can serve as a therapeutic candidate or diagnose a disease in its early stages. In order to fully understand the binding interactions, the study begins with defining some of the fundamental concepts, principles, and analytical tools for biosensing.

Afterwards, we addressed …

Assessing Threats To Plant Populations: Linking Pollinator Differences To Patterns Of Plant Fitness And Population Genetics, Rieka Yu

Dissertations

Land use change is a major driver of biodiversity loss and consequently has led to the loss of genetic diversity in many plant populations due to declines in population sizes and an increase in spatial isolation. However, not all plant populations respond similarly to land-use change, suggesting there are additional mechanisms mediating plant population genetic patterns. Here, I examine the role of pollinators as this mediating factor. In Chapter 1 I conducted a meta-analysis to investigate how different types of pollinators drive changes in gene flow for plant populations in disturbed habitats, finding that different types of pollinators mediate different …

Probing Amyloid-Beta Protein Structure And Dynamics With A Selective Antibody, Shikha Grover

Dissertations

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. The AD brain is characterized by significant neuronal loss and accumulation of insoluble fibrillar amyloid-β protein (Aβ) plaques and tau protein neurofibrillary tangles in the brain. However, over the last decade, many studies have shown that the neurodegenerative effect of Aβ may in fact be caused by various soluble oligomeric forms as opposed to the insoluble fibrils. Furthermore, the data suggest that a pre-fibrillar aggregated form, termed protofibrils, mediates direct neurotoxicity, and triggers a robust neuroinflammatory response.

Antibodies targeting the various conformation of Aβ are important therapeutic agents to prevent the progression …

Genetic And Environmental Drivers Of Microbial Colonization In Wild Birds, Sage Rohrer

Dissertations

Wild birds are teeming with microorganisms, ranging from commensal bacteria to eukaryotic parasites. These microbes impact host health in diverse ways; some long-term residents may aid digestion or provide immune system training, while others at times may induce disease. However, the factors driving the varying colonization patterns seen across taxa are still not fully understood, and wild avian populations are particularly understudied when compared to mammalian or domesticated systems. This work examines the relative importance of genetic and environmental factors driving microbiome composition and function in wild birds. We collected fecal and blood samples from Galapagos penguins (Spheniscus mendiculus …

Ferrocenium Salt Aided Substitution Reactions And Synthesis Of Glycosylated Curcumin Derivatives, Deva Saroja Talasila

Dissertations

Organic synthesis has been significantly advanced with the employment of transition metal complexes. The discovery of transition metal catalysts provided the synthetic community with powerful tools for accelerating reactions and making them more selective and efficient. Many chemical reactions do not happen without a catalyst.

Iron-based catalysts have several advantages for the chemical industry because it is a non-toxic and ecologically friendly metal. Our group previously found that ferrocenium cations with a 3+ oxidation state of iron-catalyzed propargylic substitution reactions at low temperatures. The sandwich structure of ferrocenes allows substituents to be introduced on the cyclopentadienyl rings, which allows for …

The Ecology And Evolution Of Species Rarity In Oaks (Quercus Spp.), Yingtong Wu

Dissertations

Rare species are susceptible to extinction due to ecological and genetic factors. Understanding the distribution, ecology, and evolution of rare species can provide useful information for effective conservation. To investigate species rarity, this dissertation focuses on a species-rich and ecologically diverse genus, Quercus (oaks). In Chapter 1, I aimed to understand how interactions between hosts and soil microbes contribute to habitat restriction in oak species. I performed a soil inoculum experiment on two pairs of sister oak species that show habitat divergence. I found that host-specific soil microbes contribute to habitat divergence and exclusion among sister species of oaks, but …

The Effects Of Prescribed Fire On Ant-Mediated Seed Dispersal In Missouri, Eva M. Colberg

Dissertations

Many aspects of animal-mediated seed dispersal are vulnerable to disturbance, including partner identity and dispersal quantity and quality. This dissertation explores ant-mediated seed dispersal of the herb Sanguinaria canadensis in Missouri Ozark oak forests, where prescribed fire is a common land management tool. In Chapter 1, I test the definition of a keystone seed disperser using absolute and relative contributions of different ant species to the quantity and distance of seed dispersal, based on field observations of S. canadensis seed dispersal. I demonstrate that the ant Aphaenogaster rudis is better described as a numerically dominant rather than keystone seed disperser, …

Immune Cell-Protein Interactions In Alzheimer’S Disease, Kapur Dhami

Dissertations

Misfolded protein aggregates are one of the significant contributing factors in many neurogenerative diseases including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and others. My PhD research project was to study various aspects of amyloid-β peptide, a 40-42-residue peptide and the primary component of the senile plaques found in Alzheimer’s disease (AD) brains. One objective of my research was to purify and characterize the intermediate Aβ42 species using an array of biophysical techniques like size exclusion chromatography, fluorescence assays, circular dichroism, cellular assays, and protein assays. The other major research thrust of my project was to study the role of microglial …

Mechanism Of Sila- And Germafluorenes For Biological Applications, Shelby Jarrett

Dissertations

2,7-disubstituted silafluorenes and germafluorenes, originally designed for OLED applications, are a class of fluorescent dyes that have gained recent interest as probes for bioimaging and as biosensors to monitor cellular dynamics and interactions. Desirable biological probes absorb in the visible region, have high extinction coefficients, high quantum yield and excellent photostability. Here, their spectral properties are investigated under aqueous conditions for relevant biological applications. These molecules display intense blue fluorescence in the solid state and in solution, have high extinction coefficients, and exhibit appreciable solubility in aqueous solution. To better understand potential applications, the mechanism of fluorescence was investigated. It …

Effects Of Forest Restoration On The Recovery Of Dead Wood, Associated Arthropods, And Insect-Mediated Wood Decomposition, Estefania Fernandez Barrancos

Dissertations

Dead wood represents 8% of terrestrial carbon stocks and is an important source of habitat and food for decomposer and non-decomposer arthropods. However, anthropogenic disturbance reduces the amount of dead wood, putting at risk the presence of a habitat that is essential for many arthropods and other organisms that rely on it for food and shelter. Forest restoration aims to assist the recovery of ecosystems that have been damaged or destroyed and could be a means to recover both dead wood and its associated arthropod communities. This doctoral dissertation lies at the intersection of climate change, biodiversity loss and ecological …

Liquid Biopsies For Type 2 Diabetes Mellitus: Biomarkers For Disease Risk And Diagnosis, Stephanie Chidester

Dissertations

Background: Type 2 diabetes mellitus (T2DM) has reached epidemic proportions in the United States. There is a critical need for earlier and more effective screening and diagnostic tools. Innovative liquid biopsy technologies may play a key role in meeting this need. Liquid biopsies are a non-invasive, adjunctive tool for determining diagnosis, prognosis, and therapeutic response. This dissertation focuses on two potential applications of liquid biopsy technologies to T2DM: (1) epigenome-wide association studies to identify epigenetic markers of risk for T2DM, and (2) extracellular vesicle (EV)-based biomarker studies to identify and detect markers associated with T2DM development and progression. Dissertation studies: …

Cognitive Ecology Of Color Vision In Orchid Bees, Andreia Queiroz Santos A Figueiredo

Dissertations

Animals interact with their environment and acquire information from it. Information can be processed by their sensory systems and influence behavior, often mediated through mechanisms of decision-making and learning. Animal pollinators acquire information from flowers and use this information to make decisions about the flowers they visit. My research aimed to understand the role of color vision in a tropical pollinator, the orchid bee Euglossa dilemma. Chapter 1 is a review exploring pollination through the lens of prepared learning. Prepared learning proposes that animals learn some associations better than others due to an evolved match with the environment. I …

Complexation Of Glycoalkaloid Α- Tomatine With Sterols And Its Potential Application As An Anti-Cancer Drug, Bishal Nepal

Dissertations

Glycoalkaloids (GAs) are secondary metabolites found mostly in higher plant species and some marine invertebrates. They are known to form complexes with 3β-hydroxy sterols such as cholesterol causing membrane disruption. So far the visual evidence showcasing the complexes formed between glycoalkaloids and sterols has been mainly restricted to some earlier studies using Brewster angle microscopy. This study aimed to develop a method for topographic and morphological analysis of sterol-glycoalkaloid complexes. Langmuir-Blodgett (LB) transfer of monolayers comprising of glycoalkaloid tomatine, sterols, and lipids in varying molar ratios onto mica followed by AFM examination was performed. The AFM method used required minimal …

Interactions Of The Nlrp3 Inflammasome Complex, Nyasha Makoni

Dissertations

The innate immune system is the first line of defense in response to invasion by pathogens. One of the major pathways in the innate immune system involves a three-protein complex known as the NLRP3 inflammasome. This complex comprises of NLRP3, ASC, and procaspase-1. In response to stimuli, the inflammasome assembles to activate caspase-1 which subsequently facilitates production of interleukin-1β (IL-1β), an inflammatory cytokine. The NLRP3 inflammasome has been implicated in a variety of inflammatory disorders including Alzheimer’s disease (AD). Amyloid beta (Aβ) is the protein that causes AD and Aβ deposits in the brain activate microglia resulting in chronic inflammation. …

Identification And Characterization Of Novel Genes And Genetic Interactions That Influence Iba Metabolism, Vanessica Jawahir

Dissertations

Indole-3-butyric acid (IBA) is an endogenous storage auxin important for maintaining appropriate indole-3-acetic acid (IAA) levels that influences primary root elongation and lateral root development. IBA is metabolized into free IAA in the peroxisome in a multistep process similar to fatty acid β-oxidation. Although many components specific to IBA metabolism and peroxisome function have been identified, our understanding is incomplete. I sought to identify novel components of IBA metabolism or peroxisome function by conducting a forward genetic screen for Arabidopsis thaliana plants with enhanced resistance to IBA. I identified Long chain acyl-CoA synthetase 4 (LACS4) as a novel gene functioning …

The Role Of Plasticity In Bumble Bee Responses To Environmental Variability, Matthew Austin

Dissertations

An aim of contemporary biology is elucidating the causes and consequences of phenotypic plasticity. Here, I approach this aim by exploring the eco-evolutionary dynamics of phenotypic plasticity and environmental variability in bumble bees (Apidae: Bombus), a congeneric clade of eusocial pollinating insects. Throughout their evolution, bumble bees have encountered spatiotemporal variability imposed by dynamic floral environments. Today, bumble bees additionally encounter spatiotemporal variability imposed by anthropogenic environmental change. In this dissertation, I explore how phenotypic plasticity affects how successfully bumble bees respond to environmental variability imposed by anthropogenic global change (Chapters 1 and 2) and their floral resources (Chapters …

A Strategic Plan To Thread Genomics Competencies Into Undergraduate Curriculum, Holly Mathis

Dissertations

Problem: Genomics in undergraduate nursing education has experienced slow adoption in the United States. Various approaches have been proposed but do not address barriers to successful implementation.

Methods: A strategic plan was developed to increase the amount of genetics and genomic content in the curriculum of an undergraduate nursing program. A gap analysis was performed on the curriculum revealing a paucity of content. A SWOT analysis informed the strategic plan, which included a faculty education program using the ANA/ISONG’s Essentials of Genetic and Genomic Nursing: Competencies, Curricula Guidelines and Outcome Indicators (2^nd ed.) (2009) as a foundation.

Results: Faculty …

Investigating Drivers Of Genetic Structure In Plants: Global, Regional And Local Scales, Diana Gamba-Moreno

Dissertations

Genetic structure within and among plant populations is a critical component of plant biodiversity, informing local adaptation, conservation, and incipient speciation. However, its drivers remain poorly understood, especially across different spatial scales. In my dissertation I examined factors that affect plant population genetic structure at global, regional, and local scales. At the global scale, I performed a literature review of population genetic differentiation (F_ST) in seed plants based on a 337-species dataset with data on F_ST and species traits. Using phylogenetic multiple regressions, I found that F_ST is higher for tropical, mixed-mating, non-woody species pollinated by …

Sedative And Neurotoxic Properties Of Brexanolone Compared To Midazolam In The Developing Rodent Brain, Jacob Huffman

Dissertations

The developing brain is susceptible to extensive neurotoxicity following exposure to sedative/anesthetic drugs (SADs). Every year hundreds of thousands of children around the world are exposed to SADs with no viable non-neurotoxic agents approved for clinical use. Allopregnanolone (AlloP) has well-established sedative effects in adults and neonates. AlloP and many SADs produce sedation/anesthesia through allosteric modulation of GABA_A receptors, which is one of two principal mechanisms behind SAD-induced neurotoxicity. Evidence suggests AlloP has the unique capacity to regulate key apoptotic factors in adults and is widely involved with critical stages of neurodevelopment, indicating this neurosteroid might serve as a …

Increasing Patient Adherence To Gestational Weight Gain Goals In Pregnancy, Annie Vining

Dissertations

Abstract

Problem: The inability to maintain healthy weight gain during pregnancy may contribute to multiple pregnancy-related complications. Nutritional education and support may improve nutrition and vitamin consumption, and recommendations for healthy gestational weight gains have been published. However, pregnant women have reported minimal advice regarding healthy weight gain during pregnancy. A personalized, nutritional counseling program was initiated in a Midwestern, suburban OB-GYN private practice.

Methods: A quality improvement descriptive, correlational design was used. A cohort of pregnant women first trimester through six-weeks postpartum received individual counseling and face-to-face interaction at an office visit each trimester.

Results: Twenty ( …

Vines In The Neotropics: Phylogenomics, Biogeography And Systematics In Passion Flowers (Passiflora Subgenus Decaloba Section Decaloba), Serena Acha

Dissertations

With 600 species, Passiflora is a large, morphologically complex and broadly distributed genus in Passifloraceae that represents a major challenge to scientists interested in understanding the evolutionary history of tropical vines. Passiflora has been divided into subgenera, super sections and sections. One of the most enigmatic and species-rich (~120 spp.) groups in Passiflora is section Decaloba, which occurs in the Neotropics and is particularly diverse in Andean montane forests. In this study, we used phylogenomic and population genomic approaches to investigate the evolutionary history, biologeography, species boundaries, and taxonomy of Passiflora section Decaloba. We sampled herbarium specimens, extracted …

The Role Of Multidrug Resistance Regulators Mara, Soxs, Rob And Rama In Regulating Virulence Traits In Salmonella Enterica, Srinivas Thota

Dissertations

Enteric pathogens sense numerous signals specific to the anatomical location in the intestine and integrate them with the complex regulatory networks to temporally and spatially regulate their virulence genes. MarA, SoxS, Rob and RamA are homologous transcription factors that belong to AraC family of proteins in Salmonella enterica that primarily were thought to be involved in rendering antibiotic resistance to bacteria by up regulating efflux pumps and down regulating outer membrane porins. The fact that these transcription factors respond to the same intestinal compounds that regulate virulence genes in Salmonella motivated us to look for other roles of these transcription …

Regional And Historical Influences On The Spatial Distribution Of Neotropical Trees, Maria Isabel Loza

Dissertations

At small spatial scales, the composition of species assemblages depends on local conditions and the dispersal of propagules from surrounding regions. In turn, processes taking place at broad temporal and spatial scales, including changes in regional physiography and climate, shape the species pools in these source regions. This dissertation seeks to understand the effects of regional and historical processes on the spatial distribution of Neotropical tree species. In chapter 1, I investigate regional enrichment of local species assemblages testing two hypothesis: i) local species assemblages are enriched by unfiltered species pools, which are composed of all species that can …

A Computational Study Of Sleep And The Hemispheres Of The Brain, Tera Ashley Glaze

Dissertations

Sleep and sleep cycles have been studied for over a century, and scientists have worked on modeling sleep for nearly as long as computers have existed. Despite this extensive study, sleep still holds many mysteries. Larger and more extensive sleep-wake models have been developed, and the circadian drive has been depicted in numerous fashions, as well as incorporated into scores of studies. With the ever-growing knowledge of sleep comes the need to find more ways to examine, quantify, and define it in the context of the most complex part of the human anatomy – the brain. Presented here is the …

Taxonomy, Species Limits, And Phylogenetic Relationships Of Anoura Gray 1838 (Chiroptera: Phyllostomidae), Camilo Andres Calderon Acevedo

Dissertations

This dissertation addresses several aspects of the diversity and species limits in the nectarivorous bat genus Anoura Gray 1838(Chiroptera: Glossophaginae). Based on morphometric approaches, the current taxonomic arrangement for Anoura includes 8 to 10 species; however, previous taxonomic revisions did not include all closely related species in the genus. In Chapter 1, I investigate the identity of Anoura carishina and its position in the morphospace of the large-bodied Anoura using craniodental and external variables. I analyze traits thought to be diagnostic for these species, including 1) an elliptical Fourier transformation analysis of the shape of the third upper premolar …

Phylogeographic Relationships Of Coereba Flaveola And Their Malaria Parasites, Meghann Humphries

Dissertations

This dissertation is broadly focused on elucidating how the geographic structure and demographic changes in host and parasite populations relate to one another, and how such interactions contribute to the generation and maintenance of biological diversity.

I begin by investigating the population structure of the Coereba flaveola (bananaquit) population within Puerto Rico, which is the apparent source of several expansions of the species into the Lesser Antilles. These findings indicate that both island and taxon effects influence the observed demographic changes. Because susceptibility to antagonists is related to both host species-specific characteristics and to geographical location, coevolutionary outcomes of these …

Peroxisomal Protein Defects Disrupt Coordinated Peroxisomal Processes And Affect Early Seedling Development Through Accumulating Toxic Catabolic Intermediates, Ying Li

Dissertations

Many peroxisomal proteins act in β-oxidation processes on a range of substrates. It is unclear how these proteins are coordinated to determine the flux of peroxisomal processes and meet the requirements for plant growth and development. Using mutant analysis and metabolic profiling, I examined proteins predicted to act in fatty acid and indole-butyric-acid (IBA) β-oxidation. ECH2 confers enoyl-CoA hydratase activity for the auxiliary β-oxidation of fatty acids with an even cis-unsaturated bond. ECH2 was suggested to function in IBA β-oxidation, as ech2 seedlings have altered IBA response. ech2 seedlings have reduced root length and cotyledon area. ech2 seedlings accumulate 3-hydroxyoctenoate …

The Influence Of Stressful Life Events On The Development Of Type 2 Diabetes, Joshua Minks

Dissertations

This study examined the relationship between distress and the development of Type 2 diabetes mellitus (T2DM) in the presence of established risk factors. Distress secondary to mental health disparities, stressful life events, and work conditions has been shown to promote insulin resistance and the development of T2DM.

Subjects (N=79) diagnosed with T2DM within the previous six months were recruited from SSM Health Centers and VA Medical Centers in the greater St. Louis area. They completed the Recent Life Changes Questionnaire, ENRICHD Social Support Instrument, and a demographic survey and analyses were conducted to determine differences between the veteran …

Systematics Of Malesian-Pacific Piper (Piperaceae), Rani Asmarayani

Dissertations

Comprised of ~2400 spp., Piper is a major clade in the magnoliid angiosperms. Three major groups are recognized in Piper, i.e., the Neotropical, Asian and South Pacific. Unlike Neotropical Piper,relationships in the Paleotropical Piper remain enigmatic. This study focused on the Paleotropical Piperwith emphasize on the Malesian-Pacific Piper, Malesia being the center of diversity of the genus in the Paleotropics. The goals are to evaluate relationships within Paleotropical Piper (chapter 1), to evaluate characters, morphological (chapter 1) and stem anatomical (chapter 2), that may distinguish clades, and to investigate the species boundaries focusing on the well-supported …