Life Sciences Commons^™

Trade-Offs Between Survival And Reproduction In Starvation-Selected Drosophila Melanogaster, Tammara Beeghly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evolutionary outcomes are demonstrated by traits that affect an organism’s schedule of reproduction and survival. These life history traits are reflected in an organism’s physiology, development and behavior. Environmental changes, such as availability of nutritional resources, can profoundly affect evolutionary outcomes of individuals and populations. When shortages arise, there will be trade-offs in the allocation of resources, where one trait prevails at the expense of another.

In the laboratory, we can mimic conditions in nature and study the specific effects of the conditions that we re-create. In our case, over 100 generations of Drosophila melanogaster have been selected for starvation …

Uncovering New Mechanisms Of Cdc34 And Cullin-Ring Activity, Spencer Hill

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ubiquitylation is a cellular regulatory system found in all eukaryotic cells, which has managed to find a role in most pathways imaginable. The system works fundamentally through the ligation of a small protein known as ubiquitin onto a substrate. Depending on the context of the ubiquitin ligation, the substrate can be directed towards a number of cellular fates, the best-studied being degradation of the substrate. While originally thought of as a signal for cellular disposal units to degrade aberrant proteins, we now know that ubiquitin plays a highly nuanced role in cellular epistasis, controlling everything from the cell cycle to …

The Perplexing Paradox Of Clostridioides (Clostridium) Difficile Infection (Cdi) - Analysis Of Anti-Germinants As Part Of Cdi Prophylaxis, Christopher Yip

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridioides (Clostridium) difficile infections (CDI) have become the leading cause of nosocomial antibiotic-associated diarrhea worldwide. Under normal circumstances, bacteria found in the gastrointestinal tract provide a barrier against C. difficile colonization. Upon antibiotic therapy, the protective barrier is lost as the microbial community becomes depleted thus providing the opportunity for C. difficile to colonize the human gut. Exposure to taurocholate, a bile acid produced within the mammalian gastrointestinal tract, causes C. difficile spores to begin their transition, a process known as germination, from metabolically dormant structures to toxin-producing cells. As germination is required for the onset of CDI, anti-germination compounds …

Mojave Desert Ecosystem Recovery: Potency Of Biotic And Abiotic Restoration Methods In Low Elevation Plant Communities, Mary Amanda Balogh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The historic and current state of land in the Mojave Desert, including land managed by the National Park Service with fundamental goals of natural resource conservation and preservation, been severely degraded by a variety of anthropogenic disturbances. Due to increasingly sporadic and unpredictable precipitation patterns, land managers struggle to implement restoration projects with high success rates and are resource-limited for post-treatment monitoring. In this study, I examined success rates of biotic (outplanting, seeding) and abiotic (soil manipulation, vertical mulch) restoration treatments on various disturbance types in the creosote-bursage (Larrea tridentata-Ambrosia dumosa), blackbrush (Coleogyne ramosissima), and Joshua tree woodland (Yucca brevifolia) …

Mojave Desert Plant Community Long-Term Response To Disturbance, Dominic M. Gentilcore

UNLV Theses, Dissertations, Professional Papers, and Capstones

All vegetation communities have been shaped by disturbances. This dissertation consists of three separate chapters: Blackbrush (Coleogyne ramosissima) natural regeneration in the Great Basin-Mojave Desert Transition Zone on two fires, Long-term Response to Fire in Eastern Mojave Desert semi-arid shrubland communities, and an Annotated Checklist of Gold Butte National Monument in the Mojave-Colorado Plateau Transition Zone. The section on blackbrush natural regeneration was a long-term dataset from two fires in Basin and Range National Monument that burned in 2008 with monitoring events in 2009, 2010, 2011, 2018 and 2019. The monitoring documented some of the strongest post-fire regeneration for the …

The Effect Of Pleistocene Glacial - Interglacial Cycles On Patterns Of Genetic Diversity And Differentiation Of Populations Of Leptodactylus Albilabris (White-Lipped Frog) In The Puerto Rican Bank, Andre Nguyen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The historical distributional shifts of various species have been attributed to the glacial-interglacial cycles of the Pleistocene Epoch (2.6 mya – 10,000 ya). Sea level changes caused by Pleistocene glacial-interglacial cycles impacted the total area of landmasses, particularly in island systems. Cooler, glacial periods increased emergent (subaerial) island area via lower sea levels. Adjacent islands may have become connected through emergent land bridges, resulting in a larger subaerial landmass. Warmer interglacial periods led to higher sea levels, which in turn reduced island area, and in some cases, submerged land bridges, fragmenting larger islands into separate, smaller units. The Puerto Rican …

Restructuring Of The Axon Initial Segment In Mouse Models Of Neurodevelopmental Disorders, Rachel Ali Rodriguez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Neurodevelopmental disorders (NDDs) affect more than 36% of children in countries with low- and middle- incomes (Boivin, 2015; McCoy, 2016). Interestingly, these heterogeneous disorders share a high incidence of epileptic seizures, suggesting a shared pathology. Seizures result when neuronal firing activity becomes disturbed and neurons fire excessively or in unregulated patterns. A key site in the control of neuronal firing patterns is the axon initial segment (AIS), where the local density of proteins and the morphology of the AIS in part determine the firing of neurons. We hypothesized that a disruption in the morphology and/or composition of the AIS can …

Discovering Motor Phenotypes In Autism Spectrum Disorder: A Cross-Syndrome Approach, Daniel Edwin Lidstone

UNLV Theses, Dissertations, Professional Papers, and Capstones

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with a behavioral phenotype characterized by persistent deficits in social communication and social interaction accompanied by restricted, repetitive patterns of behaviors, interests, or activities. Currently in the US, approximately 2.5% of children have a diagnosis of ASD. The etiology of ASD is complex, however the disorder does have a strong genetic basis. Specific genetic mutations can lead to neuroanatomical and neurophysiological changes during development resulting in a behavioral phenotype that falls along the ASD spectrum and may result in a diagnosis of ASD. The severity of ASD-specific behaviors falls on a continuum …

Landscape Scale: Inter- And Intraspecific Variation In Plant Interactions Along A Stress Gradient In The Sheep Range Of Nevada, Jordan Dowell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Impending threats to shrubland ecosystems, posed by climate change, necessitate niche modeling efforts to project vegetation range shifts. However, efforts often remain unguided by individual-scale interspecific plant interactions. The stress gradient hypothesis posits that facilitation should increase in areas of high abiotic stress, only if the individuals are able to ameliorate the surrounding area via functional traits. The Sheep Range of Nevada was used to assess the role of functional traits as predictors of plant association. Larrea tridentata, Coleogyne ramosissima, and Artemisia nova were selected as shrubs with variable life history strategies and ranges in order to identify general patterns …

Reduced Gabaergic Signaling At The Axon Initial Segment Decreases Vigilance State Transitioning, Austin John Boren

UNLV Theses, Dissertations, Professional Papers, and Capstones

Sleep is a highly regulated homeostatic process that is disrupted in an estimated 50-70 million Americans. Regulation of sleep depends upon coordinated signaling of multiple neurotransmitter systems. In particular, inhibitory gamma-aminobutyric acid (GABA) signaling is required to suppress wake-active brain regions in order to initiate and maintain sleep states. GABA type A receptors (GABAARs) are ionotropic receptors with subunit compositions uniquely enriched on subcellular domains of target cells. α2 subunit-containing GABAARs are the primary target of GABA released onto the axon initial segment (AIS), a site critical for phasing the oscillatory activity of cortical cells. α2-containing GABAARs have previously been …

Optimization Of Motor Performance, Lee-Kuen Chua

UNLV Theses, Dissertations, Professional Papers, and Capstones

According to the OPTIMAL (Optimizing Performance Through Intrinsic Motivation and Attention of Learning) theory of motor learning, enhanced expectancies (EE), autonomy support (AS), and external focus (EF) augment the coupling of a person’s actions to intended movement goals. This goal-action coupling is postulated to boost a person’s focus on goal-related aspects of the motor task while reducing the person’s self-related thoughts, resulting in enhanced performance of skilled movements as well as in improving the acquisition outcomes for the learning of motor skills. The three studies in this compilation report were aimed at providing empirical evidence for the motor performance benefits …

Multi-Polygenic Risk Score Prediction Model For Bipolar Disorder, Travis Mize

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bipolar disorder (BP), a severe mental disorder characterized by recurring manic and depressive episodes, has been shown to have a strong genetic underpinning. Current theory suggests that it is the summation of risk alleles, spread across the entirety of the genome, which contributes to the development of BP, as well as other polygenic traits. The comorbid nature of these polygenic traits are often problematic for diagnosticians as the symptomology of the disorders may vary substantially between individuals and can create diagnostic confusion. To alleviate issues such as these, a more objective measure, to be used alongside current diagnostic procedures, is …

Application Of Semi-Hydrophobic Layers To Decrease Bare Soil Evaporation, Jesse Lee Barnes

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evaporative water loss from bare agricultural soils is a primary area of water conservation research. Mulching is the commonly utilized method to decrease evaporative water loss. The most commonly utilized mulch is nonbiodegradable polyethylene sheeting because it tends to decrease evaporative water loss and increase crop yields more than environmentally friendly mulches. This study aimed to test the utility of sand coated with polymerized soybean oil (i.e., hydrophobic sand) as a treatment to reduce bare soil evaporation and an alternative to current practices. Evaporation rates were measured in laboratory soil columns containing both treated and untreated soils. Treatment parameters were …

Triglyceride Metabolism Following Oral Fat Tolerance Tests Of Varying Fat Content In Adults, Nathaniel Glen Bodell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Investigations of lipid metabolism commonly utilize an oral fat tolerance test (OFTT) to elicit a dramatic increase in serum triglycerides (TG). Although this is common practice there does not currently exist an agreed upon formula for an OFTT. Nor has there been in investigation as to the reliability among commonly used OFTT. Furthermore, the effects of sex and activity level are mixed among the literature. The purpose of this investigation is to discover an ideal OFTT for research and clinical purposes, evaluate the effects of activity and sex on TG metabolism, and to test each OFTT concentration for reliability. …

The Effects Of Vascular Endothelial Growth Factor On The Characteristics Of Pluripotent Dental Pulp Stem Cells, Cale Forgues

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many believe that stem cells hold the key to regenerative medicine. Therefore, research with stem cells has become increasingly popular over the years. Three specific groups of study have become present in literature. The first group has focused much of their research on harvesting and cultivating stem cell lines to retain their pluripotent ability. Stem cells can be tricky to cultivate and preserve over time as they will often differentiate or die. Another group examines the specific characteristics that a pluripotent stem cell has and how to retain, or even create, a cell with pluripotent potential. Lastly, the third group …

Optimizing Back Squat Performance, Arthur Hockwald

UNLV Theses, Dissertations, Professional Papers, and Capstones

The back squat is a task commonly used to train and test performance levels in competitive sports and strength based performance events. The purpose of this study was to analyze the potential performance benefits for a 1-repetition max (1RM) back squat under conditions in which the three key factors of OPTIMAL theory of motor learning (Wulf & Lewthwaite, 2016) are present: Enhanced expectancies (EE), autonomy support (AS), and an external focus (EF) of attention. Participants (N = 23) were assigned to either an optimized condition, which included EE AS, and EF, or a control condition. They were asked to perform …

Prevalence Of Aggregatibacter Actinomycetemcomitans And Fusobacterium Nucleatum Among Clinical Orthodontic Saliva Samples, Jason Robert Klingler

UNLV Theses, Dissertations, Professional Papers, and Capstones

Changes to the oral microflora occur when there are shifts in the levels of the numerous bacterial species. Changes in bacterial load occur in health, disease, and dental treatments such as orthodontics and can be detected through saliva. Many studies dealing with saliva have centered around detecting bacteria known for correlation with chronic periodontitis and caries. Fewer have focused on bacterial species that contribute to microbial shifts not strictly correlated with disease. Measuring the degree of disease progression or future susceptibility is not always possible with traditional clinical parameters alone.

Aggregatibacter actinomycetemcomitans (AA) is a bacterial strain that serves as …

College Student Depression: An Examination Of Cardiorespiratory Fitness, Gender And Sexual Orientation Diversity, And Help-Seeking Willingness, Sharon Jalene

UNLV Theses, Dissertations, Professional Papers, and Capstones

Depression is a serious illness characterized by persistent low mood, reduced cognitive capacity, and fatigue. Although treatable, depression is the leading cause of disability and ill-health worldwide and a significant contributor to suicide, the second leading cause of death for young Americans. In any given two-week period, 8.1% of adults in the United States had moderate to severe depression (2013-2016). The rate of depression for females was twice that of males and compared to the majority, sexual and gender minorities (SGM) were at a threefold risk. Furthermore, evidence suggests that depression incidence is three times higher in college students than …

Assessing Minimal-Input Restoration Strategies For Desert Soil And Vegetation Restoration, Audrey Jean Rader

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Mojave and Sonoran Deserts have been negatively impacted by anthropogenic disturbances. Considering that these ecosystems may recover on millennial timescales, research has shown that restoration techniques can be fairly successful in initiating long-term recovery processes in these sensitive environments. However, uncertainty remains as to which techniques are effective in different circumstances, such as in different climates or across different soil properties, and which techniques may best avoid unintended consequences, such as facilitating non-native plants. To reduce fugitive dust as a human health hazard, increase soil stability, and enhance wildlife habitat, further work is necessary to develop restoration techniques for …

Delineation Of Events In Centripetal Migration During Drosophila Oogenesis, Travis Tait Parsons

UNLV Theses, Dissertations, Professional Papers, and Capstones

All multicellular organisms initially start out as a single cell. This cell must use the genetic information encoded in its DNA to multiply in number and build itself into a complex multicellular organism. How this process occurs is the focus of developmental biology, a field that seeks to understand how a combination of genetic information and environmental conditions shape a cell from its beginnings as a zygote all the way to maturity. A fundamental part of this process is the ability of cells to work together in order to build complex tissues and organs. Cells achieve this coordination by using …

From Deviant Symbol To Cultural Icon? Understanding Pit Bull Stigma, Genevieve Minter

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research draws from twelve months of ethnographic data using Las Vegas as a case study to understand how pit bull owners experience and negotiate stigma in various social settings. The human-dog relationship, long rooted in utility, transformed in the modern era as animals were promoted from worker to companion. The world’s first dog register, The American Kennel Club, created breed standards and encouraged selective breeding, which influenced the idea of certain dogs being more physically “dangerous” than others. Though the pit bull is not the first dog “breed” to be the object of discrimination, it is the first dog …

Optimizing Cycle Exercise Performance During Normobaric Hypoxia Exposure, Cierra Brittany Ugale

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: The purpose of the present study was to examine whether implementing factors of OPTIMAL Theory: Enhanced Expectancies (EE), Autonomy Support (AS), and External Focus (EF) during a cycle exercise bout at a simulated altitude of 21,000 feet elevation had an effect on exercise performance and EPOC response in comparison to a control condition.

Methods: Sixteen participants (n = 8 women, n = 8 men) completed resting oxygen measurements (resting metabolic rate) between 6:00 A.M. and 8:00 A.M. Cycle exercise to fatigue at a constant workload was performed (100 W) while breathing air with reduced oxygen content to simulate exercising …

Changes In Hippocampal-Anterior Cingulate Cortex Interactions During Remote Memory Recall, Ryan A. Wirt

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spatial memory is an important cognitive process that relies on extensive neural networks throughout the brain. The hippocampus (HC) is important for the formation of these memories but over time, in a process referred to as consolidation, recall becomes increasingly reliant on other brain areas. The anterior cingulate cortex (ACC), a region within the medial prefrontal cortex, is important for spatial learning, spatial working memory, and remote memory recall, but the mechanisms underlying recall processes are still unknown. To better understand the role of the ACC and HC during memory recall, we introduced rodents into a series of spatially and …

Beyond Genetics: Addressing Activity In Microbial Ecology, Scott Christopher Thomas

UNLV Theses, Dissertations, Professional Papers, and Capstones

The field of microbial ecology is on the cusp of another revolution, one that uses synergy to address the limitations of previous studies. My dissertation is representative of the new era of research to come, through combining the latest technological advances with established classical methods to provide a more complete understanding of microbial ecosystems. In my first study, I evaluate the conservation of central carbon metabolic pathways and activity along a temperature and diversity gradient (60-95 ℃) through the use of 16S rRNA gene amplicon data, metagenome sequencing, and position-specific 13C-labeled metabolite probing. In my second study, I provide the …

Tree To Grass Water Use Ratios; Assessing Turfgrass’ High Water Use In The Urban Landscape, Tamara Wynne

UNLV Theses, Dissertations, Professional Papers, and Capstones

Water demand in the southwestern United States continues to rise. The population of the Las Vegas Valley doubled from 2000-2010 and now more than two million people call it home. The residential sector uses 60% of all water consumed in the valley. Outdoor urban landscape irrigation is responsible for 70% of all residential use. These landscapes are dominated by trees and turf grass. Although the water use of turf grass species is well studied, there are few published results about the water use of landscape trees in the desert southwest USA. To obtain a more complete picture of the tradeoffs …

Correlation Between Pluripotent Stem Cell Markers And Microrna Expression In Dental Pulp Stem Cells, Mark Whiting

UNLV Theses, Dissertations, Professional Papers, and Capstones

In human development there are many factors that cause our cells to form certain organs and systems with specific functions. These cells original start as stem cells before biological processes take over and cause differentiation into different cell lines. Since these undifferentiated stem cells have been discovered, many studies have been done to try and find the exact mechanism that causes a cell to change into another specific cell. Due to the multiple sources that stem cells can be harvest from the human body, this knowledge of how differentiation works could lead to breakthroughs in regenerative medicine.

Traditional biomarkers have …

Effects Of Ecological Restoration Techniques In Glen Canyon National Recreation Area, Simone Ka-Voka Jackson

UNLV Theses, Dissertations, Professional Papers, and Capstones

A better understanding of key ecological restoration techniques can inform land management in the Southwest on restoration options for areas infested by invasive grasses that can pose threats to ecosystems, from changes in nutrient cycling to altered fire regimes. In the semi-arid desert of Glen Canyon National Recreation Area (GLCA), several exotic grasses pose risks to local ecosystems: Saccharum ravennae, a relatively new invasive perennial grass, and Bromus rubens and Bromus tectorum, widespread annual grasses. In this study, multiple ecological restoration techniques were implemented to assess their effects on native and nonnative vegetation on sites invaded by the non-native grasses …

Workload Position Evaluation To Determine Efficient Training Load For Optimal Competition Performance Of Female Collegiate Soccer Players, Michaela Kelsey

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction. The purpose of this study was to describe player workload between competition and training of female collegiate soccer players; as well as to determine workload between positions to better our understanding of the mechanical and physical demands of a full soccer match of collegiate female soccer players. Methods. The study sample was comprised of 20 female Division 1 Collegiate soccer players in 7 positions: goalkeeper (n = 1), Attacking Midfielders (n = 2), Defensive Midfielders (n = 3), Center Backs (n = 3), Outside Backs (n = 4), Strikers (n = 2), and Wingers (n = 5). 19 training …

Effect Of Common Oxidative Water Treatments On Acanthamoeba Internalized Legionella, James Park

UNLV Theses, Dissertations, Professional Papers, and Capstones

Legionella pneumophila can cause pneumonic and non-pneumonic disease in humans. Infections occur from aerosolized contaminated water. This bacterium is an opportunistic intracellular pathogen able to infect both protozoans, such as Acanthamoeba polyphaga, and human macrophages. Both L. pneumophila and A. polyphaga resist commonly used water treatments, such as chlorination, but L. pneumophila has displayed greater resistance in the presence of A. polyphaga. Therefore, there is concern that L. pneumophila could become established in plumbing systems after water treatment, leading to infections. The objective of this study was to show the effect of chlorine and chlorine dioxide exposures on the survival …

Analysis Of Spheno-Occipital Synchondrosis (Sos) Fusion In A Contemporary Southern Nevada Subadult Hispanic Population Using Archival Cone-Beam Computerized Tomography (Cbct) Images, Megan Baker

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study employs the three-dimensional visualization capability of cone-beam computed tomography (CBCT) to investigate the relationship between chronological age and timing of fusion of the spheno-occipital synchondrosis in a male/female subadult Hispanic population of Southern Nevada. The sample includes cross-sectional data of 374 orthodontic patients (166 males and 208 females) aged 8-20 years. The SOS is scored by a four-stage scoring system as completely open (stage 0), less than half fused (stage 1), more than half fused (stage 2), or completely fused (stage 3) as visualized in the midsagittal plane in the CBCT image. The relationship between SOS fusion stage …