Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Theses and Dissertations

Discipline
Institution
Keyword
Publication Year
File Type

Articles 1 - 30 of 4357

Full-Text Articles in Life Sciences

Food Safety Risk In An Indoor Microgreen Cultivation System, Gina Marie Misra May 2020

Food Safety Risk In An Indoor Microgreen Cultivation System, Gina Marie Misra

Theses and Dissertations

Microgreens are immature sprouts of edible plants, sharing some similarities with sprouted seeds and petite leafy greens. Since they are most often grown in containers in buildings or greenhouses, they present a new area for food safety research at the intersection of the built environment and produce farming. Contamination by human pathogens has been extensively studied in other types of produce typically eaten raw, including sprouted seeds, which have been implicated in numerous outbreaks of salmonellosis over the last several decades. There is a paucity of knowledge about the microgreen sector of the fresh-cut industry; thus, it was determined that ...


Florpyrauxifen-Benzyl Use In Arkansas Rice (Oryza Sativa L.), Hannah Elizabeth Wright May 2020

Florpyrauxifen-Benzyl Use In Arkansas Rice (Oryza Sativa L.), Hannah Elizabeth Wright

Theses and Dissertations

Florpyrauxifen-benzyl is a synthetic auxin herbicide which was commercially released in 2018 to combat troublesome grass, broadleaf, and sedge weed species in rice. Many factors may influence cultivar response to a new herbicide; hence, it is important to understand factors contributing to crop sensitivity to an herbicide in order to make appropriate recommendations. Prior to the onset of this study, research had been conducted on florpyrauxifen-benzyl in a flooded environment; however, none had been executed in a non-flooded environment. Experiments were conducted to evaluate the response of a long-grain variety ‘CL111’, a medium-grain variety ‘CL272’, and a long-grain hybrid ‘CLXL745 ...


The Release, Transport, And Utilization Of Phosphorus From Bed-Sediments: A Study Of A Eutrophic Littoral Cove On Beaver Lake In Northwest Arkansas, James A. Mccarty May 2020

The Release, Transport, And Utilization Of Phosphorus From Bed-Sediments: A Study Of A Eutrophic Littoral Cove On Beaver Lake In Northwest Arkansas, James A. Mccarty

Theses and Dissertations

Eutrophication of surface waters not only impacts the environment but also water treatment processes, the most significant of which is from the effects of algae. During peak algal growth in many southern U.S. reservoirs, inflows that bring nutrients are at an annual minimum, and phosphorus released from bed-sediments is trapped in the hypolimnion. Littoral areas, described as the most productive zone of the lake, may be a possible source of phosphorus that fuels algal growth in the reservoir. I studied an isolated shallow cove in the War Eagle Creek arm of Beaver Lake in Northwest Arkansas to measure, quantify ...


Epigenetic Alterations At Synaptic Plasticity Genes In A Genetically Heterogeneous Rat Model Of Neuropsychiatric Disorders, Doan M. On Jan 2020

Epigenetic Alterations At Synaptic Plasticity Genes In A Genetically Heterogeneous Rat Model Of Neuropsychiatric Disorders, Doan M. On

Theses and Dissertations

Sensorimotor gating impairments are observed across a range of neuropsychiatric conditions. The prepulse inhibition of the acoustic startle response (PPI) is a validated measure of sensorimotor gating. Genetic and pharmacological manipulations in rodents have shown PPI is regulated by specific brain monoaminergic systems. Using genetically heterogeneous NIH-HS rats, we stratified individuals by %PPI. In low PPI animals, we observed elevated mRNA levels of certain neurotransmitter receptors, including metabotropic glutamate receptor Grm2, dopamine receptors Drd1 and Drd2, serotonin receptors Htr1a and Htr2a, and scaffolding protein Homer1, in the frontal cortex (FC) and striatum (STR). We found Drd2 mRNA levels were significantly ...


Senescent Trees Stabilize Aboveground Wood Net Primary Production Immediately After Disturbance, Maxim S. Grigri Jan 2020

Senescent Trees Stabilize Aboveground Wood Net Primary Production Immediately After Disturbance, Maxim S. Grigri

Theses and Dissertations

In the United States, forests sequester 17% of national carbon (C) emissions annually (UGCRP, 2018), however shifting forest disturbances threaten the stability of this essential C sink. Unlike the high severity, stand-replacing disturbances that were widespread a century ago, today’s eastern temperate forests experience frequent low-to-moderate severity disturbances from invasive pests and pathogens with mixed effects on net primary production (NPP). Carbon cycling stability after disturbance has been reported, however, the mechanisms underlying immediate NPP stability or decline are not well understood. Through weekly measurements of production in a landscape scale experiment, we show that the sustained growth of ...


Application Of Optical Trapping To Obtain Single-Source Str Profiles From Forensically Relevant Body Fluid Mixtures With Modified Dna Analysis Workflow, Benjamin J. O'Brien Jan 2020

Application Of Optical Trapping To Obtain Single-Source Str Profiles From Forensically Relevant Body Fluid Mixtures With Modified Dna Analysis Workflow, Benjamin J. O'Brien

Theses and Dissertations

Current methods of mixture separation in forensic DNA laboratories typically deconvolute the mixture after analysis using statistical analysis or probabilistic genotyping. To save time and effort of labs already backlogged, a method to separate mixtures on a cellular level before analysis needs to be developed. Optical trapping is a method that uses a focused 1064 nm laser to manipulate cells. Previous research has shown that approximately 50 spermatozoa or 15 leukocytes from a liquid sample are required to produce a full STR DNA profile. It was found that the number of spermatozoa required remains constant when the method of sample ...


Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon Jan 2020

Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon

Theses and Dissertations

Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive ...


The Role Of Ca2+/Calmodulin Dependent Protein Kinase Ii, Camk-Ii, In Kidney Morphogenesis, Sarah R. Ingram Jan 2020

The Role Of Ca2+/Calmodulin Dependent Protein Kinase Ii, Camk-Ii, In Kidney Morphogenesis, Sarah R. Ingram

Theses and Dissertations

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common heritable diseases in the world, characterized by the development of large fluid filled cyst. Treatments for this disease are limited due to a lack of understanding of disease pathogenesis. Ca2+/calmodulin dependent protein kinase II (CaMK-II) is necessary for kidney morphogenesis in zebrafish as well as being a downstream effector of pkd2, one of the genes most commonly mutated in ADPKD patients. The roles of CaMK-II during zebrafish kidney development include regulation of kidney cell migration as well as cloacal cilia stability. The influence of CaMK-II on ...


Synaptic Plasticity In A Visual Cortical Region Induced By Early-Deafness, John M. Kay Jan 2020

Synaptic Plasticity In A Visual Cortical Region Induced By Early-Deafness, John M. Kay

Theses and Dissertations

When organisms learn and adapt to their environment or lose a sensory modality, neurons in the brain undergo a cellular process called ‘plasticity.’ This thesis explores the loss of a non- visual system (early deafness) and how it can affect visual plasticity. To examine this question, Golgi-stained cortical neurons were studied from the visual region PLLS from early-deaf cats and their hearing controls. Dendritic spine density and dendritic spine diameter are well-known indicators of synaptic plasticity and these neuronal features were measured using light microscopic techniques and Neurolucida. Within the visual PLLS, the mean spine density for the deaf cats ...


Mathematical Models Of Cellular Signaling And Supramolecular Self-Assembly, Pratip Rana Jan 2020

Mathematical Models Of Cellular Signaling And Supramolecular Self-Assembly, Pratip Rana

Theses and Dissertations

Synthetic biologists endeavor to predict how the increasing complexity of multi-step signaling cascades impacts the fidelity of molecular signaling, whereby cellular state information is often transmitted with proteins diffusing by a pseudo-one-dimensional stochastic process. We address this problem by using a one-dimensional drift-diffusion model to derive an approximate lower bound on the degree of facilitation needed to achieve single-bit informational efficiency in signaling cascades as a function of their length. We find that a universal curve of the Shannon-Hartley form describes the information transmitted by a signaling chain of arbitrary length and depends upon only a small number of physically ...


The Impact Of Aging And Mechanical Injury On Alveolar Epithelial And Macrophage Responses In Acute Lung Injury And Inflammation, Michael S. Valentine Jan 2020

The Impact Of Aging And Mechanical Injury On Alveolar Epithelial And Macrophage Responses In Acute Lung Injury And Inflammation, Michael S. Valentine

Theses and Dissertations

Patients with severe lung pathologies, such as Acute Respiratory Distress Syndrome (ARDS), often require mechanical ventilation as a clinical intervention; however, this procedure frequently exacerbates the original pulmonary issue and produces an exaggerated inflammatory response that potentially leads to sepsis, multisystem organ failure, and mortality. This acute lung injury (ALI) condition has been termed Ventilator-Induced Lung Injury (VILI). Alveolar overdistension, cyclic atelectasis, and biotrauma are the primary injury mechanisms in VILI that lead to the loss of alveolar barrier integrity and pulmonary inflammation. Stress and strains during mechanical ventilation are believed to initiate alveolar epithelial mechanotransduction signaling mechanisms that contribute ...


Non-Native Leaf Litter Modifies Algal Resources With Effects On Tadpole Growth, Spencer L. Cruz Dec 2019

Non-Native Leaf Litter Modifies Algal Resources With Effects On Tadpole Growth, Spencer L. Cruz

Theses and Dissertations

Leaf litter species play a key role in determining the quality and quantity of algal resources in aquatic ecosystems as a cross-boundary subsidy. The invasion of non-native plant species into forests can alter aquatic resources. I investigated the effects of non-native leaf litter species on algal resources and green frog, Lithobates clamitans, development using a randomized complete block experiment that lasted 288 days. In experimental ponds, I added two non-native and two native leaf litter species in the presence and absence of tadpoles. Early in the experiment, Japanese honeysuckle and Chinese privet decreased periphyton N:P ratios and stimulated tadpole ...


Functional Importance Of Lipin Phosphorylation, Stephanie Elizabeth Hood Dec 2019

Functional Importance Of Lipin Phosphorylation, Stephanie Elizabeth Hood

Theses and Dissertations

Highly conserved throughout evolution, lipins are dual functioning proteins found from yeast to humans. Functioning in the cytoplasm as phosphatidate phosphatase enzymes (PAP), lipins produce diacylglycerol that serves as a precursor for neutral fats and membrane phospholipids. Alternatively, nuclear lipins are responsible for the regulation of metabolic genes. Interestingly, both the mammalian lipin 1 paralog and the single Drosophila Lipin ortholog are highly phosphorylated proteins. Target of rapamycin (TOR) has previously been identified as one of the kinases that controls the subcellular localization of both lipin 1 and Drosophila Lipin. However, other serine and threonine kinases are predicted to be ...


Species Richness And Ecological Diversity Of Myxomycetes And Myxomycete-Like Organisms In The Tropical Forests Of Brazil, Isadora Lima Coelho Dec 2019

Species Richness And Ecological Diversity Of Myxomycetes And Myxomycete-Like Organisms In The Tropical Forests Of Brazil, Isadora Lima Coelho

Theses and Dissertations

Tropical rain forests cover less than two percent of Earth's surface, yet they sustain the greatest diversity of living organisms on the planet. Tropical rain forests cover nearly 73% of the Brazilian territory and besides harboring some of the most biodiverse ecosystems on the planet, this vast area also houses about 83% of the Brazilian population. Approximately 175 million people live in urban and rural areas with fragments of coverage of these biomes which contributes to the loss of biodiversity that rapidly increases over the years. Furthermore, the majority of the taxonomic and ecological efforts to describe and protect ...


Cyanobacterial Harmful Algal Bloom Ecology And Cyanotoxins In The Eutrophic Lake Winnebago-Green Bay Water System, Sarah L. Bartlett Dec 2019

Cyanobacterial Harmful Algal Bloom Ecology And Cyanotoxins In The Eutrophic Lake Winnebago-Green Bay Water System, Sarah L. Bartlett

Theses and Dissertations

Cyanobacterial harmful algal blooms (cyanoHABs) are frequently observed in water bodies used for recreation and drinking water production and can be detrimental to humans, animals, and general water quality. CyanoHABs are natural occurrences, but human activities such as agriculture, land use change, and runoff from urban and rural landscapes can promote and accelerate their expansion. The blooms are aesthetically unpleasing scums and can be laden with toxins (cyanotoxins) and toxic or otherwise bioactive peptides (TBPs) that can be harmful to humans and animals. Despite the vast research on cyanoHABs, cyanotoxin and TBP diversity and dynamics within a water column are ...


Sexual Dimorphism And The Shape Of The Proximal Tibia In A Radiographic Sample, Emily Eiseman Dec 2019

Sexual Dimorphism And The Shape Of The Proximal Tibia In A Radiographic Sample, Emily Eiseman

Theses and Dissertations

SEXUAL DIMORPHISM AND THE SHAPE OF THE PROXIMAL TIBIA IN A RADIOGRAPHIC SAMPLE

This study investigates the use of radiographs to determine sexual dimorphism in the shape of the tibia. The goal of the research was to identify a small set of markers that would allow researchers to efficiently and accurately determine a person’s sex from a radiograph of the proximal tibia.

The sample consisted of radiographs including 75 females and 46 males ranging in age from 21 to 81. Measurements were taken on 27 points around the area of the knee including the tibia, patella, and femur. The ...


Heirloom And Hybrid Corn In The American Corn Belt: An Ethnography Of Seed Saving Practices, Rachelle Halaska Dec 2019

Heirloom And Hybrid Corn In The American Corn Belt: An Ethnography Of Seed Saving Practices, Rachelle Halaska

Theses and Dissertations

This ethnographic study examines the practices and context of contemporary heirloom corn seed saving practices and projects in the American Corn Belt. It examines heirloom corn conservation and hand pollination practices at Seed Savers Exchange in Decorah, Iowa in 2015. From there the study extends to interviews with heirloom farmers, breeders and gardeners in Wisconsin and Illinois. The findings indicate that the lines between the mainstream and the margins of corn production are highly blurred, and that there is a considerable amount of cross-pollination of ideas and practices between alternative corn farming and dominant industrial hybrid production in the American ...


Two Fields, One Pellet: Combining Demographics And Population Genetics Through Non-Invasive Sampling Of Snowshoe Hare Fecal Pellets In Michigan., Genelle Nicole Uhrig Dec 2019

Two Fields, One Pellet: Combining Demographics And Population Genetics Through Non-Invasive Sampling Of Snowshoe Hare Fecal Pellets In Michigan., Genelle Nicole Uhrig

Theses and Dissertations

As climate continues to change at a rapid rate, species are increasingly vulnerable to the resulting environmental changes. This is especially true for species whose fitness is closely linked to climate-associated environmental conditions. One of these vulnerable species is snowshoe hare, Lepus americanus, who depends on the timing and duration of snowfall to provide camouflage when they go through seasonal pelage changes from brown in the summer to white in the winter. Whereas snowshoe hare are stable across the core of their range, populations along the southern range edge are experiencing declines due to climate driven environmental changes that cause ...


Toward Understanding The Mechanism Of Protein Targeting In The Chloroplast Signal Recognition Particle Pathway, Mercede Furr Dec 2019

Toward Understanding The Mechanism Of Protein Targeting In The Chloroplast Signal Recognition Particle Pathway, Mercede Furr

Theses and Dissertations

Protein targeting is a vital cellular function. The signal recognition particle (SRP) pathway is a universally conserved targeting system present in the cytosol and used to co-translationally target many proteins to the inner membrane of prokaryotes and the endoplasmic reticulum of eukaryotes. The chloroplast has a homologous SRP system which post-translationally targets light harvesting chlorophyll binding proteins (LHCPs) to the thylakoid membrane for integration. The chloroplast SRP (cpSRP) is a heterodimer with a 54 kDa subunit equivalent to SRP54 in the canonical pathway. In addition, cpSRP contains a novel 43 kDa subunit which is a unique and irreplaceable component. cpSRP43 ...


Global Acetylation Dynamics In The Heat Shock Response Of Saccharomyces Cerevisiae, Rebecca E. Hardman Dec 2019

Global Acetylation Dynamics In The Heat Shock Response Of Saccharomyces Cerevisiae, Rebecca E. Hardman

Theses and Dissertations

All organisms face a constant barrage of environmental stresses. Single-cell organisms such as Saccharomyces cerevisiae, or common Baker’s yeast, must rely solely on cellular responses in order to survive. This response must occur in a rapid and highly coordinated manner to quickly inhibit all unnecessary processes and shuttle all available resources to those necessary for survival. One method that cells utilize for rapid protein regulation is the use of post-translational modifications. Enzymes within the cell add or remove a variety of chemical modifications, thus altering the local chemical environment of a protein. This creates a conformational change in the ...


The Effects Of Seed-Applied Fluopyram On Root Penetration And Development Of Meloidogyne Incognita On Cotton And Soybean, Tracy Hawk Dec 2019

The Effects Of Seed-Applied Fluopyram On Root Penetration And Development Of Meloidogyne Incognita On Cotton And Soybean, Tracy Hawk

Theses and Dissertations

Plant-parasitic nematodes are major pests of cotton and soybean in Arkansas, and across the Southern United States. These nematodes cause more than $3 billion worth of crop losses each year, in part due to lack of available control tactics, such as nematicides. Fluopyram has recently been registered as a seed-treatment nematicide in agronomic crops. The toxicity of fluopyram against Meloidogyne incognita infection has been reported, however, information on root protection provided by fluopyram against Meloidogyne incognita is lacking. The first objective of this research was to evaluate the effect seed-applied fluopyram had on nematode development, root galling, and reproduction on ...


Use Of Aerial Imagery And Novel Experimental Design To Determine The Distribution Of Foliar Diseases On Soybean And Improve Efficiency Of Product Testing, Mckayla Patterson Dec 2019

Use Of Aerial Imagery And Novel Experimental Design To Determine The Distribution Of Foliar Diseases On Soybean And Improve Efficiency Of Product Testing, Mckayla Patterson

Theses and Dissertations

Soybeans are grown on approximately 1.3 million ha in Arkansas generating an estimated $1.7 billion annually. Foliar diseases on soybean can result in economic losses. Growers spend significant time and money on disease scouting via crop consultants and often (subsequent) fungicide applications. Fungicide trials are often arranged in small plots designs. In these scenarios, spatial variability of foliar disease is minimized. While it is advantageous to minimize variance outside of treatment differences, another limitation with many small plot trials is ample disease pressure or having only lower severity. Within a commercial production field, soil types and disease severities ...


Anti-Inflammatory Effects Of Cruciferous And Apiaceous Vegetables In C57bl/6j Mice Colon, Rosa Moreno Narvaez Dec 2019

Anti-Inflammatory Effects Of Cruciferous And Apiaceous Vegetables In C57bl/6j Mice Colon, Rosa Moreno Narvaez

Theses and Dissertations

Previous studies have demonstrated chemo-preventive potential of cruciferous and apiaceous vegetables against colon cancer. Colon inflammation is one condition closely related with colon cancer initiation. Therefore, we wanted to compare if total western diet (TWD) was as pro-inflammatory as died-induced obesity (DIO) and a better dietary model for human conditions, and determine if diet supplementation with cruciferous (broccoli, watercress and cabbage) or apiaceous vegetables (celery and parsnip) could reduce dietary inflammation, and which vegetable was more effective.

Male CBL57/6J mice were fed chow for seven days, on day eight, mice were assigned to one of the following diets: American ...


In Vivo Metabolic And Vascular Response To Hypoxia In Twist Knockdown Murine Breast Cancer, Brandon Sturgill Dec 2019

In Vivo Metabolic And Vascular Response To Hypoxia In Twist Knockdown Murine Breast Cancer, Brandon Sturgill

Theses and Dissertations

Twist transcription factor is often overexpressed in aggressive tumors. Although needed in early embryonic development for organogenesis, Twist is known to induce an epithelial to mesenchymal transition in cells. In cancer, epithelial to mesenchymal transitions can lead to increased motility and invasiveness. It has also been linked to metabolic reprogramming and increased metastatic risk. Furthermore, metabolic preferences can increase proliferation, enhance metastatic potential, and influence the site of metastasis. We hypothesize that Twist directly affects the metabolism of cancer cells. We expect to see in vivo what we have seen in vitro; Twist overexpression should promote a shift away from ...


The Physicochemical Properties Of Soy Protein Hydrolysate And Its Formulation And Stability With Encapsulated Probiotic, John Stricklin Edwards Dec 2019

The Physicochemical Properties Of Soy Protein Hydrolysate And Its Formulation And Stability With Encapsulated Probiotic, John Stricklin Edwards

Theses and Dissertations

Soy protein isolate (SPI) and probiotics can serve as a functional ingredient and beneficial supplement, respectively, to food formulations, but few studies focus on the compatibility of these two ingredients. The objective of this study was to prepare soy protein isolate (SPI) from defatted soybean flour and identify an optimal hydrolysis protocol to create soy protein hydrolysates (SPH) with improved solubility and functional properties and achieve an optimum encapsulation technique for probiotics and to determine the in vitro viability of encapsulated probiotic cells with SPH in a gastrointestinal environment. The SPI was prepared using an alkaline extraction procedure for solubility ...


The Relationship Between Biofilm Production And Human Respiratory Cell Attachment And Invasion By Acinetobacter Baumannii, Rachel A. Pearson Dec 2019

The Relationship Between Biofilm Production And Human Respiratory Cell Attachment And Invasion By Acinetobacter Baumannii, Rachel A. Pearson

Theses and Dissertations

Acinetobacter baumannii is an opportunistic gram-negative bacterial pathogen that causes many nosocomial infections in immunocompromised individuals. Common infections include catheter-associated urinary tract infections, ventilator-associated pneumonia, skin and soft tissue infections, and bloodstream infections that often lead to septicemia. Increasing multidrug resistance (MDR) in A. baumannii warrants new approaches to understanding its virulence mechanisms and pathogenicity. As a first step in infection, A. baumannii can attach to host cells, providing a surface for the bacteria to grow and perhaps facilitating biofilm formation and subsequent tissue invasion. In this study, we evaluated antibiotic resistance and characterized biofilm formation, attachment, invasion, and surface ...


The Feedback-Related Negativity Is A Time-Dependent Brain Mechanism That Facilitates Aversive Learning: Implications For The Reinforcement Learning Frn Hypothesis, Eric Rawls Dec 2019

The Feedback-Related Negativity Is A Time-Dependent Brain Mechanism That Facilitates Aversive Learning: Implications For The Reinforcement Learning Frn Hypothesis, Eric Rawls

Theses and Dissertations

Organisms encode rewarding and aversive experiences through reinforcement learning, capitalizing on prediction errors (PEs), which adapt action strategies over time. Computational theories are explicit that PE signals should update action weights continuously over the course of a behavioral task, an important time-dependent variation that is eschewed in traditional neuroscience studies that average over large numbers of trials. I examined variation in reaction times and feedback-locked cortical activity over time as a function of PE to critically examine theories indicating that PE signals drive time-dependent learning. We recorded EEG while participants completed a novel reinforcement task that varied prediction error on ...


Observable Persistent Effects Of Habitat Management Efforts In The Ozark Highlands After 10 Years, Maxwell Carnes-Mason Dec 2019

Observable Persistent Effects Of Habitat Management Efforts In The Ozark Highlands After 10 Years, Maxwell Carnes-Mason

Theses and Dissertations

I investigated the lasting impacts of a management plan designed to improve oak regeneration and benefit wildlife in the Ozark Highlands in Madison, Co., AR. To assess the efficacy of the management plan, I used variables relevant to the success and establishment of oak trees. Controlled burns and selective logging were used to thin the canopy, increase ground level productivity, and increase the abundance of small mammals. I used measurements of overstory and understory densities, light availability, and the density of mice in the genus Peromyscus across time to look at the lasting impacts of management. Different treatment plots were ...


Eastern Collared Lizard (Crotaphytus Collaris) Population Declines In Ozark Landscapes: An Assessment Of Environmental Constraints., Casey L. Brewster Dec 2019

Eastern Collared Lizard (Crotaphytus Collaris) Population Declines In Ozark Landscapes: An Assessment Of Environmental Constraints., Casey L. Brewster

Theses and Dissertations

The Eastern Collared Lizard (Crotaphytus collaris) has experienced extensive population declines over the past half century in the Ozark Mountains. Previous research suggests that glade habitat degradation through woody vegetation encroachment is an important factor resulting in population declines. In this dissertation I used information on time-energy budgets to investigate the link between habitat degradation and shifts in life history traits likely resulting in population declines of Eastern Collared Lizards (Crotaphytus collaris) in the Ozarks. In chapter one, I addressed the influence of dense woody vegetation encroachment on age-specific growth, body size, body condition and reproduction of C. collaris in ...


Natural Variation In Yeast Stress Signaling Reveals Multiple Paths To Similar Phenotypes, Amanda N. Scholes Dec 2019

Natural Variation In Yeast Stress Signaling Reveals Multiple Paths To Similar Phenotypes, Amanda N. Scholes

Theses and Dissertations

Natural environments are dynamic, and organisms must sense and respond to changing conditions. One common way organisms deal with stressful environments is through gene expression changes, allowing for stress acclimation and resistance. Variation in stress sensing and signaling can potentially play a large role in how individuals with different genetic backgrounds are more or less resilient to stress. However, the mechanisms underlying how gene expression variation affects organismal fitness is often obscure.

To understand connections between gene expression variation and stress defense phenotypes, we have been exploiting natural variation in Saccharomyces cerevisiae stress responses using a unique phenotype called acquired ...