Digital Commons Network^™

From Myzocytosis To Cytostomal Nutrient Uptake And Transport By Intracellular Plasmodium Species, T. Y. Sam-Yellowe

Biological, Geological, and Environmental Faculty Publications

No abstract provided.

Microglial Response To Glucocorticoids During Chronic Sleep Fragmentation, Christian Chelson

Masters Theses & Specialist Projects

Sleep is one of the body’s greatest and most basic needs. Chronic sleep loss (<6 hours a day) is linked to many cardiovascular issues, diabetes, and inflammatory conditions and has been shown to lower life expectancy. Obstructive sleep apnea (OSA) is a complication that causes sleep fragmentation in >8% of adults from developed countries, and many with OSA may be unaware of their condition. Having long-term OSA is linked to neuroinflammation caused by activated microglia in the brain, but the mechanics of this inflammation are not well understood. It is known that glucocorticoids, steroid hormones produced and released from the adrenal glands, have a suppressive effect on microglia. The purpose of this study is to explore the role that glucocorticoids have upon microglia activation induced by chronic sleep fragmentation (SF). C57BL/6J mice were …

Behavioral Response To Conspecific Sounds In Loricariid Catfishes (Pterygoplichtys Pardalis And Otocinclus Vittatus), Hephzibah Obafunmiso

Masters Theses & Specialist Projects

Sound production is a means of communication among many fish species. In fishes, sound is produced through various mechanisms, but in the family Loricariidae, known as armored suckermouth catfishes, sound is produced primarily through pectoral fin spine stridulation. Previous experiments have described the sounds produced and shown the mechanism of sound production in two species of loricariid catfishes, Pterygoplichthys gibbiceps and Otocinclus affinis, but the functional significance of loricariid sounds is still unknown. To address this question, I examined the behavioral responses of Pterygoplichthys pardalis and Otocinclus vittatus to conspecific calls. Individual fish (N=10 for P. pardalis) or groups …

A Comparison Of Computational Perfusion Imaging Techniques, Shaharina Shoha

Masters Theses & Specialist Projects

Dynamic contrast agent magnetic resonance perfusion imaging plays a vital role in various medical applications, including tumor grading, distinguishing between tumor types, guiding procedures, and evaluating treatment efficacy. Extracting essential biological parameters, such as cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT), from acquired imaging data is crucial for making critical treatment decisions. However, the accuracy of these parameters can be compromised by the inherent noise and artifacts present in the source images.

This thesis focuses on addressing the challenges associated with parameter estimation in dynamic contrast agent magnetic resonance perfusion imaging. Specifically, we aim …

Assessing The Effect Of Reservoirs On Gene Flow In The Southern Two-Lined Salamander (Eurycea Cirrigera), Anna Favalon

Masters Theses & Specialist Projects

Biodiversity is an essential component of natural environmental dynamics. Unfortunately, diversity is threatened by human activities and relies on conservation efforts. An important aspect of biodiversity conservation lies in protecting population connectivity and gene flow. In the mid-1900s, many Kentucky rivers were dammed, creating deep, lentic reservoirs in the valleys once occupied by dynamic, lotic rivers. For species inhabiting the rivers and associated tributaries, the central reservoirs may reduce connectivity among populations and impose a barrier to gene flow. The connectivity of populations on landscapes altered by the creation of reservoirs can be assessed by merging the principles of landscape …

Mechanisms Behind The Chaperone Activity Of Nucleic Acids, Theodore J. Litberg

Electronic Theses and Dissertations

Understanding the interplay between nucleic acids and protein aggregation is integral to the understanding of proteostasis, aging, and neurodegenerative disease progression. Nucleic acids are known to modulate the aggregation of PrP, tau, ⍺-synuclein, and other disease relevant proteins. Although the interactions between misfolded protein and nucleic acids can play a role in disease, this interaction may potentially be beneficial as well. Our group and others have shown nucleic acids can be powerful chaperones. Previous work has shown both RNA and DNA can prevent protein aggregation and RNA can pass off protein clients to the heat shock protein (Hsp) system. Here …

Characterization Of Legionella Pneumophila Effector Proteins, Lneb And Mava, Kayode Adeyemi

Masters Theses & Specialist Projects

The crucial virulence factor of accidental human pathogen Legionella pneumophila during the course of Legionnaire disease is the over 300 effector proteins secreted from its Dot/Icm secretion system. Eukaryotic host cells usually elicit an arsenal of immune responses against invading L. pneumophila. Nonetheless, the bacteria unexpectedly subvert these defense mechanisms to survive and proliferate unhindered in the host. Although some effector proteins have been proposed to play a significant role in this host-pathogen interaction, many still need to be characterized. The LneB and MavA proteins are examples of those effectors that need characterization. Thus, this study aimed to investigate the …

Mammalian & Avian Community Response To African Elephant (Loxodonta Africana) Habitat Modification In Southeastern Kenya, Dakota Vaccaro

Masters Theses & Specialist Projects

African elephants (Loxodonta africana) play a significant role in the modification of their habitat, foremost by decreasing woody vegetation cover and density and in some parts of Africa high elephant densities damage small sanctuaries and preserves. For wildlife that depend on forested patches, this increased modification could lead to displacement and/or decreases in abundance. If suitable habitat is not available elsewhere, elephants and other wildlife may move closer to humans in search of resources, which can result in increased human-wildlife conflict. Evaluating this impact was one of the goals of the Elephants and Sustainable Agriculture in Kenya (ESAK) …

Will Molecular Phylogenetics Help Decrease Nomenclatural Instability?, Peter Lesica, Matt Lavin

Biological Sciences Faculty Publications

Commentary - no abstract available.

Polar Body Membrane Breakdown Occurs Independent Of Macroautophagy In C. Elegans, Shruti Kolli

Electronic Theses and Dissertations

Failure to digest cell corpses can lead to lupus-like autoimmune disorders in mammals. To better understand if LC3-associated phagocytosis (LAP) drives cell corpse breakdown in phagolysosomes, we studied the clearance of the C. elegans polar body during embryonic development. ATG16L1 has separable roles in regulating LC3 recruitment during macroautophagy and LAP. We demonstrated that the ATG16L1 C. elegans orthologs, ATG-16.1 and ATG-16.2, function redundantly to promote polar body membrane breakdown. We also discovered that truncating the LAP-specific WD40 domain of ATG-16.2 unexpectedly disrupts autophagy. Furthermore, we confirmed that polar body membrane breakdown occurs independent of macroautophagy. We also showed that …

A Genotype × Environment Experiment Reveals Contrasting Response Strategies To Drought Between Populations Of A Keystone Species (Artemisia Tridentata; Asteraceae), Anthony E. Melton, Kara Moran, Peggy Martinez, Paige Ellestad, Erin Milliken, Walker Morales, Andrew W. Child, Bryce A. Richardson, Marcelo Serpe, Stephen J. Novak, Sven Buerki

Biology Faculty Publications and Presentations

Western North America has been experiencing persistent drought exacerbated by climate change for over two decades. This extreme climate event is a clear threat to native plant communities. Artemisia tridentata is a keystone shrub species in western North America and is threatened by climate change, urbanization, and wildfire. A drought Genotype × Environment (G × E) experiment was conducted to assess phenotypic plasticity and differential gene expression in A. tridentata. The G × E experiment was performed on diploid A. tridentata seedlings from two populations (one from Idaho, USA and one from Utah, USA), which experience differing levels of …

Long-Term Spring Through Fall Capture Data Of Eptesicus Fuscus In The Eastern Usa Before And After White-Nose Syndrome, Molly Simonis, Lynn K. Hartzler, Joshua Campbell, Timothy C. Carter, Lisa Noelle Cooper, Katelin Cross, Katherine Etchison, Traci, R. Andrew King, Richard J. Reynolds, Yasmeen Samar, Michael Yasmeen, Sarah Stankavich, Gregory G. Turner, Megan A. Rúa

Biological Sciences Faculty Publications

Emerging infectious diseases threaten wildlife populations. Without well monitored wildlife systems, it is challenging to determine accurate population and ecosystem losses following disease emergence. North American temperate bats present a unique opportunity for studying the broad impacts of wildlife disease emergence, as their federal monitoring programs were prioritized in the USA throughout the 20 th century and they are currently threatened by the invasive fungal pathogen, Pseudogymnoascus destructans ( Pd ), which causes white-nose syndrome. Here we provide a long-term dataset for capture records of Eptesicus fuscus (big brown bat) across the eastern USA, spanning 16 years before and 14 …

Impacts Of Dam Removal On Cyanobacteria Blooms And Zooplankton Community In Hypereutrophic Upper Klamath Lake, Pruett Noelle Kasey

Biology Theses - Archive

The Chiloquin Dam was removed from the Sprague River in 2008 to restore the natural hydrology of Upper Klamath Lake (UKL), allow fish access to historical spawning grounds, and alleviate the effects of long-term eutrophication. This provided a natural opportunity to investigate the effects of restoration efforts on eutrophication. Using a 10-year dataset including 5 years before and 5 years after dam removal, we developed a consensus modeling approach to investigate factors contributing to the cyanobacteria blooms, observe changes in the ecosystem since the recovery efforts, and to assess the performances of three model types: logistic regression, random forest, and …

Molecular Mechanisms That Regulate The Stress Response In A. Baumannii, Feroz Ahmed

Biology Dissertations - Archive

Acinetobacter baumannii is particularly problematic in hospital settings, where infections can occur in a range of tissues. This bacterium can endure extreme stress from various antimicrobial agents, biocides, host immune response etc. Not much is known about how these bacteria react to such high stress. A. baumannii also possesses a unique ability to inactivate lipooligosaccharide (LOS) biosynthesis, which is an essential molecule in most Gram-negative bacteria. LOS is enriched in the outer membrane and is the targeted by the last-resort antibiotic, colistin. LOS-deficient A. baumannii is highly resistant to the list-line antimicrobial. Previously, our lab discovered that a two-component system, …

Biodiversity In The Anthropocene, Understanding The Impacts Of Land-Use Change, And Species Interactions., Alexander H. Murray

Biology Dissertations - Archive

The extent of human influences on the environment and biodiversity has led to naming our current time period the Anthropocene. A primary way in which humans impact biodiversity is through habitat modification. Despite the knowledge that habitat modification is negative for many species, we still don’t understand why some species are able to persist despite habitat modification while others do not. In my first chapter I used a trait-based approach to understand what determines species’ sensitivity to habitat modification. Trait-based approaches from different regions often disagree on the importance of the same traits, and I thought climate and land use …

Determining How Anthropogenic Change Filters Biological Communities And How Species Modify Their Traits In Response To Urbanization, Kristopher Warren Row

Biology Dissertations - Archive

Humans are significantly altering the environment at an alarming pace, leading to a reduction in species diversity. This transformation has created modified habitats where some species struggle to survive, while a few others not only manage to survive but thrive. One of the most drastic forms of habitat modification is urbanization, which is spreading worldwide and contributing to the decline of biodiversity. Urbanization has given rise to urban-tolerant species that differ ecologically from species that avoid urban areas across various niche dimensions. These urban-tolerant species must adapt to changes in food sources, microhabitat conditions, and alterations in physical habitat structures. …

An Investigation Of Freshwater Turtle Ecology Using Stable Isotopes, Jonathan Duran

Biology ETDs

In 2022 I investigated niche partitioning among native and invasive freshwater turtles across three sites in the Middle Rio Grande using bulk stable isotope analysis. I found high degrees of niche partitioning at sites in which Red-eared sliders (Trachemys scripta) have yet to establish. However, at sites in which red-eared sliders are now the most abundant species they overlapped greatly in isotopic niche with all native turtles, in particular the painted turtle (Chrysemys picta). Using these same techniques, I then examined the trophic interactions between red-eared sliders and their acanthocephalan parasites. My results suggest that acanthocephalans …

Diversification By Dispersal Out Of The Andes Revealed By A Newly Discovered Hummingbird Clade, The ‘True Brilliants’, Marialejandra Castro-Farías

Biology ETDs

We identified a novel clade with striking biogeographic implications. Unsampled genera, Hylonympha and Sternoclyta, were found to be close to the genus Heliodoxa within the Brilliants. Heliodoxa tend to occur in lower montane habitats, such as the tropical, upper tropical, and subtropical elevational zones of the Andes and the Neotropics. Analysis of geographic and elevational zones showed that genus Heliodoxa and related genera diversified by out-of-Andes dispersal to mountain ranges of Central America, coastal Venezuela, the Pantepui, and southeastern Brazil, since the mid-Miocene. Within the Brilliants, reductions in elevation preceded these geographic expansions. Secondary colonization of the lowlands from …

Post-Fire Plant Community Response In Subalpine Mixed Conifer Forest, Sasha Escamilla

Biology ETDs

Increased wildfire activity may lead to significant shifts in vegetation dynamics in high elevation mixed conifer forests. These changes raise concerns about the resilience of forests following wildfire, prompting the need for a deeper understanding of post-fire plant community response. We analyzed up to 11 years of post-fire vegetation data from Valles Caldera National Preserve in northern New Mexico to determine how burned vegetation sites were recovering following high severity wildfire, and whether or not plant communities were transitioning to montane grassland. We found burned understory herbaceous communities were not transitioning into distinctive montane grasslands and were instead recovering to …

Evidence Of Competitive Release Following Overstory Mortality In A Semi-Arid Piñon-Juniper Woodland, Corrie D. Gonzalez

Biology ETDs

Extreme temperatures and severe drought events have led to widespread tree mortality worldwide. In semi-arid regions of the Southwest United States, these events pose a significant threat to piñon-juniper (PJ) woodlands. We studied the effects of piñon and juniper mortality on the growth and physiology of existing saplings in PJ woodlands by analyzing water status, photosynthetic activity, and tissue chemistry to gain insights into these impacts. Juniper saplings exhibited improved water status and water use efficiency in response to overstory mortality, whereas piñon saplings did not. Additionally, both piñon and juniper saplings exhibited increased photosynthetic rates, increased photosynthetic capacity, and …

Thermoregulation In Nocturnal Volant Endotherms Occupying Hot Deserts, William A. Talbot

Biology ETDs

The study of thermoregulation is of growing concern in this era of rapid climate change. Earlier studies such as those pioneered by Scholander and Bartholomew directed focus toward the study of endotherm survival in conditions of cold weather adversity. As techniques evolved in the measurement of parameters quantifying thermoregulation, metabolism and energy allocation, the standardization procedures has increased the comparability of data from diverse taxa. We can now search historical records and current research for explanations to the changes in the distribution, migration, extirpation or survival of animal and plant populations through time. It is increasingly common to observe dramatic …

Resolving The Paradox Of Polyploidy: Underexplored Facets Of Polyploid Plants, Benjamin P. Gerstner

Biology ETDs

Polyploidy, or whole genome duplication, is a common phenomenon in plants, but the establishment and persistence of mixed-ploidy populations remains a paradox. This dissertation explores factors that contribute to the persistence and establishment of mixed-ploidy populations in nature. The first chapter investigates the role of unreduced gametes in neopolyploid establishment and finds that variability in their formation rate can have a significant impact on polyploid establishment and persistence. The second chapter searches for evidence of soil microbes exhibiting ploidy-specificity, a pre-condition for microbe-mediated niche differentiation, a possible stabilizing mechanism contributing to ploidy coexistence. Finally, the third chapter tests for microbe-mediated …

Trophic Assessment Of The Invasive Hydrozoan Gonionemus Vertens Using Stable Isotope Analysis : You Are What You Eat, Diana Sisk-Gritz

Theses, Dissertations and Culminating Projects

Gonionemus vertens, commonly known as the clinging jellyfish, is a small hydrozoan known for their conflicts with humans due to their neurotoxins that can lead to paralysis. Native to the Pacific Ocean, it has now invaded numerous ecosystems in the coastal waters of the Mediterranean Sea, Europe, and the United States. In the United States, it has flourishing populations from New Jersey to Maine. However, many questions remain as to how it arrived and spread, but equally important is what impact this species may have in the invaded communities they now reside. Research suggests that G. vertens actively feeds on …

Cullin 3–Mediated Regulation Of Intracellular Iron Homeostasis Promotes Thymic Invariant Nkt Cell Maturation, Emily L. Yarosz, Ajay Kumar, Jeffrey Singer, Cheong-Hee Chang

Biology Faculty Publications and Presentations

The E3 ubiquitin ligase cullin 3 (Cul3) is critical for invariant NKT (iNKT) cell development, as iNKT cells lacking Cul3 accumulate in the immature developmental stages. However, the mechanisms by which Cul3 mediates iNKT cell development remain unknown. In this study, we investigated the role of Cul3 in both immature and mature thymic iNKT cells using a mouse model with a T cell–specific deletion of Cul3. We found that mature iNKT cells lacking Cul3 proliferated and died more than wild-type cells did. These cells also displayed increased glucose metabolism and autophagy. Interestingly, we found that tight regulation of iron homeostasis …

Consistency Is Key: Investigating Vocal Consistency In Field Sparrows, Stephanie Stanton

Masters Theses

No abstract provided.

Cellular Heat Responses Of Desert Mammals Promote Survival In Extreme Conditions, Janessa Montenegro

UNLV Theses, Dissertations, Professional Papers, and Capstones

Increasing temperatures with the potential for heat stress is among the future threats facing many mammals. Cellular mechanisms to maintain homeostasis in the face of heat stress likely differ across species based on naturally tolerated intracellular variability. In some mammals, the homeostatic set point in cells has a narrow range. Other species tolerate more varied intracellular conditions, including in temperature. Heat stress responses of cultured dermal fibroblasts from several mammals were compared to detect cell proliferation and cellular death (chapter 2). Cells from heat- tolerant species (13-lined ground squirrel, dromedary camel, round-tailed ground squirrel, and white-tailed antelope squirrel) were compared …

Visual Circuitry In Adaptive Behavior: Extraction Of Complex Visual Image Information By Arrays Of Non-Image Forming Eyes, Thomas Kipp Halladay Groves

Dissertations

A complete understanding of how neural circuitry underlies the detection and integration of visual cues continues to elude researchers in the 21st century. Since the dawn of life on earth, light has exerted enormous selective pressure on all living organisms. Visual systems represent one of the most common sensory systems in existence, with significant homologies among elements of these systems, such as photopigments and developmental genes. Offering nearly unmatched single cell access at all levels of its nervous system, the European medicinal leech (Hirudo spp.) is an excellent system in which to identify behaviorally relevant neuronal circuits. Hirudo evolved discrete …

Mate Choice And Sexual Conflict In A Livebearing Fish, Julia C. Kasper

Master's Theses

Eavesdropping occurs when a receiver extracts information from an interaction without directly engaging with the signaler. Eavesdropping has been shown to be an effective way of evaluating the quality of potential mates and their abilities in male-male competition, without having to directly interact with them, thereby reducing energy costs and mating harassment. Girardinus metallicus is a livebearing poeciliid fish endemic to Cuba whose mating system is dominated by mating harassment in the form of sneak copulations, persistent displaying, and male-male aggression. G. metallicus has a male specific polymorphism in both melanin coloration and behavior. Males with melanin coloration are known …

Functional Analysis Of Two Campoletis Sonorensis Ichnovirus Vinnexins In Drosophila Melanogaster, Peng Zhang

All Dissertations

Campoletis sonorensis Ichnovirus (CsIV) is produced by the ichneumonid parasitoid Campoletis sonorensis (the primary host). Female parasitoid wasps restrictedly replicate viruses in their ovaries and inject them into a larval lepidopteran (secondary host) during oviposition. This symbiotic virus of C. sonorensis is essential for successful parasitization. CsIV is characterized by having a large, segmented double-stranded DNA genome with a large number of genes, many of which are associated with one of five multigene families. The CsIV vinnexin gene family is one of them and has four members, including CsIV-vnxD and CsIV-vnxG. Vinnexins are homologues of insect Innexins, which form gap …

Understanding The Environmental And Genetic Influence On Fluctuating Asymmetry And Developmental Instability In Primates, Ashly N. Romero

Graduate Theses and Dissertations

This dissertation explored the impact of environmental factors on the development and perpetuation of fluctuating asymmetry (FA) and sought to understand the role evolution may play in the FA exhibited in two primate populations: the free-ranging Cayo Santiago rhesus macaques (Macaca mulatta) and the Southwest National Primate Research Center olive baboons (Papio hamadryas anubis). Demographic, ontogenetic, secular, external, and genetic factors were examined. Specifically, this dissertation investigated FA over all ontogenetic stages, across decades, between sexes, in association with ecological catastrophes, and with tooth pathology to try and tease apart factors that may influence FA and developmental instability. This dissertation …