Biology Commons^™

Variation In Phenotype, Genotype, And Somatic Diversity Among Asexual Schmidtea Mediterranea Planarians, S. Kershenbaum, Danielle Ireland, Ziad Sabry , '20, Christina Rabeler, Vir Shetty , '22, A. Aboobaker, Eva-Maria S. Collins

Biology Faculty Works

Most multicellular life reproduces sexually, utilizing a single-celled stage that acts as a genetic bottleneck. This bottleneck limits the evolution of selfish cell adaptations by ensuring all cells descend from a single progenitor. We investigated an obligately asexual strain of Schmidtea mediterranea planarians that reproduces by self-bisection and lacks a single-cell bottleneck. Using 2.5 yearlong data on planarian reproductive behavior combined with genotyping, we revealed two previously undescribed genetically distinct substrains within the CIW4 strain. One substrain showed reduced fitness, which correlated with substantial losses of heterozygosity and increased somatic diversity. By genotyping consecutive head offspring over multiple generations, we …

Nueva Metodología De Análisis Para Determinar El Delito Ambiental De Ecocidio Por Glifosato En Cultivos Permanentes De Coca En Colombia, Rosalina González Forero, Jerry H. Kavouras, Érika González Ruiz

Biology Department Faculty Articles

El crimen organizado transnacional ha sido nefasto para el territorio colombiano, en especial el asociado a la producción de coca en la última década, lo que ha generado impactos económicos y sociales debido al aumento del conflicto e inseguridad en las zonas de influencia del cultivo. Esto se debe a que en el 2023 se tenían 230 000 hectáreas sembradas, lo que representa el 20 % de la superficie del país, con un impacto ambiental no cuantificado en términos penales. Este requiere de acciones de entidades estatales, así como de cooperación internacional, para adaptar estrategias y poder judicializar estos delitos …

Structure And Function Of Type 1 Pilus Assembly Machinery In Uropathogenic Escherichia Coli, Ryan Bitter

Arts & Sciences Graduate Student Theses and Dissertations

Gram-negative bacteria produce chaperone-usher pathway (CUP) pili, which are extracellular adhesive protein fibers critical for host-pathogen interactions. An outer-membrane usher protein, together with a periplasmic chaperone, assembles thousands of pilin subunits into a pilus fiber. Each pilus is tipped by an adhesin that mediates host and tissue tropisms by binding to receptors with stereochemical specificity. Type 1 pili expressed by uropathogenic Escherichia coli (UPEC) are essential virulence factors in urinary tract infections (UTIs) and facilitate attachment to mannosylated glycoproteins on bladder epithelial cells. Although type 1 pili have been extensively studied, critical gaps remain in our understanding of the molecular …

Rna’S Symphony: Harmonizing Splice Junctions And Exon Counts For A Novel Approach To Differential Splicing Analysis, Jelard Aquino

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alternative Splicing (AS) plays a critical role in transcriptome complexity and cell-type-specific gene regulation, yet its analysis remains methodologically fragmented, especially in the context of noisy and sparse single-cell RNA sequencing (scRNA-seq) data. This dissertation addresses key computational challenges in AS detection by evaluating existing tools, developing integrative frameworks, and proposing new strategies for improving analysis accuracy in both bulk and single-cell contexts. In chapter 1, I present a comprehensive literature review of computational tools designed for detecting and quantifying AS from bulk and scRNA-seq data. This review outlines major methodological paradigms, including exon-based and splice junction-based approaches, and evaluates …

Morphological And Transcriptional Responses Of Mammalian Cells To Glucose Stress, Cassandra Burke

UNLV Theses, Dissertations, Professional Papers, and Capstones

Organismal cells encounter varying conditions, including daily and potentially seasonal fluctuations in available glucose. While some species tightly regulate circulating glucose levels, others tolerate extreme fluctuations, such as frugivorous bats experiencing post-prandial hyperglycemia and hibernating mammals maintaining stable glucose through torpor and hibernation. To investigate how these species-specific strategies influence cellular responses to glucose perturbation, primary dermal fibroblasts from nine mammals – humans, rats, Egyptian fruit bats, brown bear, 13-lined ground squirrel, little brown bat, gelada, honey badger, and Bactrian camel – were exposed to hypoglycemic (2.5mM), baseline (8mM), or hyperglycemic (30mM) treatment. Cell morphology was evaluated using Cell Painting, …

An Analysis Of The Influence Of Human Disease Pathogens On Core Behaviors Of The Black-Legged Tick, Emily F. Marinko

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ixodes scapularis, the black-legged or deer tick, is a vector for several different disease-causing microbes, including the causative agent of Lyme disease. As such, it is a major health concern for people living within its range in the eastern half of the United States, a habitation area that is increasing due to climate change. Despite its medical relevance as a disease vector, there is still much to learn about the basic behavior of these arachnids in the wild. Thus, the major hypothesis of this thesis is that ticks that are infected with specific human disease-causing microbes behave differently than those …

Diverse Cell Types Establish A Pathogenic Immune Environment In Peripheral Neuropathy, Julie Choi

Arts & Sciences Graduate Student Theses and Dissertations

Neuroinflammation plays a complex and context-dependent role in many neurodegenerative diseases. We identified a key pathogenic function of macrophages in a mouse model of a rare human congenital neuropathy in which SARM1, the central executioner of axon degeneration, is activated by hypomorphic mutations in the axon survival factor NMNAT2. Macrophage depletion blocked and reversed neuropathic phenotypes in this sarmopathy model, revealing SARM1-dependent neuroimmune mechanisms as key drivers of disease pathogenesis. In this study, we investigated the impact of chronic subacute SARM1 activation on the peripheral nerve milieu using single cell/nucleus RNA-sequencing (sc/snRNA-seq). Our analyses reveal an expansion of immune cells …

Phosphorylation Deficient Inducible Camp Early Repressor (Icer) Modulates Tumorigenesis And Survival In A Transgenic Zebrafish (Danio Rerio) Model Of Melanoma, Justin Wheelan, Melissa Rose Spigelman, Angelo Cirinelli, James Reilly, Carlos A. Molina

Department of Biology Faculty Scholarship and Creative Works

Melanoma, the most lethal form of skin cancer, is commonly associated with mutations in the BRAF gene, particularly BRAF^V600E, which drives tumor proliferation via the ERK1/2 signaling cascade. While BRAF inhibitors initially demonstrate efficacy, therapeutic resistance remains a significant challenge. Emerging evidence implicates the cAMP signaling pathway, particularly the cAMP response element-binding protein (CREB) and its repressor, inducible cAMP early repressor (ICER), in melanoma progression and drug resistance. ICER, a transcriptional repressor regulated via Ras/MAPK-mediated phosphorylation and ubiquitination, is degraded in melanoma, undermining its tumor-suppressive role. In a braf^V600E; p53 (loss of function) transgenic zebrafish ( …

Protocol For Vibratome Sectioning, Immunofluorescence, And S-Phase Labeling Of Inner Ear Organoids, Jiayi Wu, Stefan Heller, Maggie S. Matern

Biology Faculty Publications

Inner ear organoids represent a potentially inexhaustible source of otic tissues, including sensory hair cells and supporting cells, for in vitro manipulation. Here, we present a protocol for labeling S-phase entry of cells in inner ear organoids using 5-ethynyl-2′-deoxyuridine (EdU), followed by fixation and vibratome sectioning. Nuclear EdU is then detected alongside protein markers of interest via immunofluorescence. This workflow enables the visualization of cell and tissue morphologies within developing organoids and assessment of how different manipulations affect cell proliferation.

Male Mating Preference For Larger Females Does Not Vary Among Age Classes In The Long-Lived Beetle Bolitotherus Cornutus, G. M. Jiron, C. A. Greene, E. D. Brodie Iii, Vincent A. Formica

Biology Faculty Works

Theory and past experimental work suggest that as males age, the strength of their mate preference should decrease. However, the empirical work investigating this question has primarily been conducted in insects that have very short life spans and often live for just a single mating season. This leaves a gap in our understanding of the relationship between male mate preference and age across taxa, as age can conflate with other ecological changes in a single mating season. In this study, we ask how the strength of preference for large female body size changes as males age in a long-lived insect, …

Expanding Functionalities Of Immune Receptors Through Simultaneous Transfer Of Sensor And Helper Nlrs, Dongjiao Wang, Qibin Wu, Daowen Wang, Youxiong Que, Zheng Qing Fu

Faculty Publications

No abstract provided.

Expanding Functionalities Of Immune Receptors Through Simultaneous Transfer Of Sensor And Helper Nlrs, Dongjiao Wang, Qibin Wu, Daowen Wang, Youxiong Que, Zheng Qing Fu

Faculty Publications

No abstract provided.

Predation By The Brown Vine Snake, Oxybelis Koehleri, On The Autotomized Tail Of An Escaping Common Anole, Anolis Humilis, Jose M. Mora, Myzell Kenneth Amaro

Biology Faculty Publications and Presentations

During a natural history hike at La Selva Biological Station in Costa Rica, we observed a Brown Vine Snake, Oxybelis koehleri, consuming the autotomized tail of a Common Humble Anole, Anolis humilis, which had escaped predation. This event represents a rare documented instance of a vine snake feeding exclusively on a detached lizard tail. Tail autotomy is a widespread anti-predator strategy among lizards, with the shed tail continuing to writhe post-detachment, potentially attracting predators. Lizard tails are lipid-rich and offer a convenient energy source, especially in resource-scarce environments. Although such behavior has been noted in other reptiles, it is seldom …

Bclaf1 Is A Novel Regulator Of Hematopoietic Stem Cells, Stephanie Crowley

Arts & Sciences Graduate Student Theses and Dissertations

Hematopoietic stem cells (HSC) maintain both a self-renewal capacity to persist throughout life and an ability to differentiate into mature cell lineages. HSC self-renewal programs are often ectopically activated in leukemia cells to sustain developmental arrest and neoplastic proliferation. Recently, the transcriptional regulator Bclaf1 (Bcl2 associated transcription factor 1) was shown to support proliferation and block differentiation of AML blasts. Bclaf1 is ubiquitously expressed in hematopoietic cells but its function in normal hematopoiesis has not been elucidated. Our data demonstrate that BCLAF1 promotes HSC development and function. To study the role of BCLAF1 in normal HSCs, we used murine models …

The Role Of The Poly-N Repeat In The Plasmodium Falciparum Histone Acetyltransferase Protein, Pfgcn5, Kely Johana Rubiano Cardona

Arts & Sciences Graduate Student Theses and Dissertations

P. falciparum possesses the most AT-rich genome sequenced to date, with long AAT repeats coding for asparagines (N) in intragenic regions. As a result, nearly a quarter of its proteome is composed of proteins with poly-N repeats. Since the discovery of its genome, the function of these repeats has remained as one of the biggest mysteries in the biology of this parasite. Furthermore, it has long been known that proteins with N-rich domains aggregate easily, particularly during heat stress (HS). Given that the hallmark of this disease is recurrent febrile episodes, it is not well understood how the parasite survives …

Computational And Mathematical Modeling Of Microbial Community And Host Responses To Microbiota-Directed Complementary Foods Administered To Children With Acute Malnutrition., Steven J. Hartman

Arts & Sciences Graduate Student Theses and Dissertations

Globally, millions of children suffer from undernutrition, with stunting affecting 150 million and wasting nearly 50 million under five years old. Current interventions have shown limited effectiveness in mitigating long-term consequences such as stunted growth, cognitive deficits, and immune dysfunction. Through this body of work, I investigated the efficacy of a microbiota- directed complementary food (MDCF-2) as a next generation therapeutic food to combat childhood stunting. Across two randomized controlled trials involving Bangladeshi children with either moderate acute malnutrition or post-severe acute malnutrition, MDCF-2 significantly outperformed standard ready-to-use supplementary foods (RUSF), leading to significantly improved ponderal and sustained linear growth …

Low-Tech Seed Enhancement Technology Could Improve Seedling Establishment Of Longleaf Pine Understory Perennial Forbs, Madeline E. Schmuck, Michael C. Disilvestro, Danny J. Gustafson

Journal of the South Carolina Academy of Science

Reintroducing native plants into restoration and revegetation projects could increase plant species diversity, increase floral resources for pollinators, and positively affect trophic-level interactions in the community. Direct seeding in restoration projects has generally had poor success rates due to biotic and abiotic factors, leading to significant seed wastage of the already insufficient native seed supply. Seed balls (aka seed aggregates, seed bombs, and seed pellets) are a low-cost, low-tech seed enhancement technology. The seeds are encased in a soil and clay matrix, providing good seed-soil contact, controlling seed planting depth, nutrients, and protection from seed predators. We conducted a greenhouse …

Thionine Modulates Tau Phosphorylation In An Alzheimer’S Disease Cell Culture Model, Seda Önder, Kevser Bi̇beroğlu, Özden Tacal

Turkish Journal of Biology

Background/aim: Tau protein, which is crucial for sustaining the cytoskeletal network by assisting microtubule construction, contributes significantly to the pathophysiology of Alzheimer’s disease (AD). The hyperphosphorylation of tau causes it to detach from microtubules (MTs), leading to the formation of neurofibrillary tangles (NFTs) in neurons, which ultimately results in cell death. Thionine (TH), a cationic phenothiazine-structured compound, has been the topic of extensive research due to its interesting physicochemical properties. It is a common biological dye, especially useful in histology due to its strong affinity for biological membranes. Furthermore, TH serves as a photosensitizer in phototherapy. It has a phenothiazine …

Different Hypoxic Response Of Human Cavii And Caenorhabditis Elegans Homologous Genes Cah-3, Cah-4, Cah-5, Sümeyye Aydoğan Türkoğlu, Aysu Bozkurt, Fatma Poyrazli, Derya Okuyan

Turkish Journal of Biology

Background/aim: A number of carbonic anhydrase (CA) family proteins have been implicated in cancer. They contribute to the hypoxic microenvironment. CAVII is often downregulated in colorectal carcinoma and it has been associated with increased tumor size, node metastasis, and adverse clinical outcomes. In this study, we aimed to investigate the effect of hypoxia on CAVII protein in human colon cancer and prostate cancer cells. In addition, the regulation of CAH genes in Caenorhabditis elegans was examined. These are homologous to CAVII in humans.

Materials and methods: CAVII expression was analyzed in different cell lines such as human colon cancer (SW480 …

Kabasura Kudineer Choornam, A Medicinal Polyherbal Formulation, Modulates Human Macrophage Polarization And Phagocytic Function, Asli Korkmaz, Duygu Ünüvar, Si̇nem Günalp, Derya Göksu Helvaci, Duygu Sağ

Turkish Journal of Biology

Background/aim: Kabasura kudineer choornam (KKC) is a polyherbal formulation of 15 ingredients. It has antiinflammatory and antimicrobial properties and are effective in managing the symptoms of H1N1 swine flu and COVID-19. However, its mechanism of action is not fully understood. In this study, we examined the effect of KKC on the polarization and function of primary human macrophages.

Materials and methods: Human monocyte-derived macrophages (M0 macrophages) pretreated with KKC extract were polarized into M1, M2a, or M2c subtypes. The expression of the M1/M2 polarization markers was analyzed using qPCR, flow cytometry, and ELISA, and the phagocytosis capacity of …

Mir-9-5p Alleviates The Development Of Abdominal Aortic Aneurysm By Regulating The Differentiation Of Cd4+Il-10+T Cells Via Targeting The Crosstalk Between Nrf2 And Nf-Κb Signaling Pathways, Hongfu Liu, Jinyi Zhang, Lubin Li, Benxiang Yu, Chunlei Zhang, Wenqiang Niu, Yawen Cheng, Hengyang Dong, Yukun Zhang, Xinlin Luo, Yanlian Xiong, Yueming Wang

Turkish Journal of Biology

Background: Abdominal aortic aneurysm (AAA), a gradual segmental dilatation of the abdominal aorta, is associated with a high mortality rate. The pathophysiological molecular mechanisms underlying AAA remain unclear. In recent years, changes in miRNA levels have been reported to be involved in the development and treatment of AAA. This study aimed to investigate the potential targets and underlying mechanisms of miR-9-5p in attenuating AAA progression by modulating the inflammatory response.

Materials and methods: Biochemical kits were used to measure the levels of inflammatory factors, antioxidant enzyme activity, and serum oxidative stress in normal and AAA model mice. miR-9-5p overexpression was …

Lactic Acid Bacteria Alleviate Neuronal Excitotoxicity And Extend Caenorhabditis Elegans Lifespan, Bao Le, Thi Nhat Hong Nguyen, Seung-Hwan Yang

Turkish Journal of Biology

Aim: Neuronal cell death plays a critical role in the development of neurological disorders associated with aging. This study aimed to evaluate the beneficial effects of heat-killed lactic acid bacteria (hkLAB) on neuroblastoma cells and Caenorhabditis elegans.

Materials and methods: We pretreated heat-killed Lactobacillus fermentum CNU384 (hkCNU384), L. brevis CNU386 (hkCNU386), L. helveticus CNU395 (hkCNU395), and L. paracasei CNU396 (hkCNU396) at a concentration of 10⁹ CFU/mL to investigate their neuroprotective effects on glutamate-induced SH-SY5Y cells and their impact on the lifespan of 6-hydroxydopamine (6-OHDA)-induced C. elegans.

Results: Our findings indicate that hkCNU395 and hkCNU396 protected against glutamate-induced cell death …

Chelidonium Majus L.-Containing Gel May Improve Diabetic Wound Healing By Modulating Mmp-2, Mmp-9, And Collagen Levels, Kaan Kaltalioğlu, Eli̇f Naz Gürsoy, Barbaros Balabanli, Zeki̇ Aytaç, Şule Coşkun Cevher

Turkish Journal of Biology

Background/aim: Delayed wound healing in diabetic patients is a significant complication that reduces quality of life, prompting the continuous investigation of new therapeutic agents. This study designed to explore the dose-dependent effects of different parts of Chelidonium majus L. (CM), a medicinal plant traditionally used for skin disorders, on diabetic skin wounds.

Materials and methods: In diabetic rats, full-thickness excisional wounds were formed. CM-containing gels (aerial parts at 3%, 6%, 9% and root at 0.5%, 1%, 1.5%) were developed and applied to the wounds. After the treatment period, the rats were sacrificed, and wound healing activity was assessed macroscopically, histopathologically, …

Abundance, Distribution, And Shoaling Of Driftfishes And Allies (Scombriformes: Stromateoidei) In The Pelagic Gulf Of Mexico, Juliet Tretler

All HCAS Student Capstones, Theses, and Dissertations

The suborder Stromateoidei contains 80 species of mesopelagic fishes in five families distributed throughout temperate and tropical seas worldwide, including the Gulf of Mexico (Gulf hereafter). Mesopelagic fishes, especially those that spatially aggregate, serve as important forage items for commercially, recreationally, and ecologically important species of fish, marine mammals, and seabirds. However, knowledge of the ecology and trophic importance of stromateoid fishes in the Gulf is extremely limited. This study provides quantitative information on the species composition, abundance, distribution, and biomass contribution of the stromateoid species to the Gulf deep-pelagic fish assemblage, with comparison to “archetypal” mesopelagic fish families (e.g., …

Understanding The Effects Of Genetic Variation On Maize And Pennycress Root System Architectures And Their Interaction With Nitrogen, Alexander Euway Liu

Arts & Sciences Graduate Student Theses and Dissertations

Roots are a critical yet hidden part of plants, providing physical support and access to resources such as nutrients and water. The development of a plant’s root system across time and space is referred to as root system architecture, which influences the effectiveness of resource capture. In modern agriculture, applications of nitrogen fertilizers are critical to maintain high yield. However, up to 70% of applied nitrogen is not utilized by the plant and escapes into waterways and the atmosphere, causing environmental harm. Efficient nitrogen uptake is limited by the ability of the plant to access and absorb nitrogen through its …

Examining Associations Between Street Vegetation And Child Firearm Violence At Microgeographic Locations In 3 Us Cities: A Case-Control Study, Zihan Lin, Gregory A. Wellenius, Jonathan Jay

Biological, Geological, and Environmental Faculty Publications

Background: Firearm violence is a leading cause of death among U.S. children under age 18. Urban vegetation, a vital component of the living environment, has been found to influence firearm violence, yet the relationship between different types of street vegetation and firearm violence with children as the victim at the microgeographic scale remains unclear.

Methods: We analyzed 2316 child firearm assault incidents from Los Angeles, New York City, and Philadelphia from 2015 to 2021. Using a spatial case-control approach, we matched assault locations with control locations within 1-km. For each location, we applied deep learning algorithms to Google Street View …

Transcription Fidelity In The Face Of Oxidative Damage, Eastilan Gyiwah Appiah

Theses and Dissertations

It is very important that the process of transcription is correctly carried out in the cell for the faithful expression of the genetic code. However, should mistakes happen, they can result in transcription errors which interfere with the protein-making machinery of the cell. This will result in accumulation of proteins and dysfunctional proteins that have the potential of causing diseases like Alzheimer’s. Oxidative damage caused by hydrogen peroxide is known to cause transcription errors in organisms like yeast. It is therefore important to investigate the extent to which hydrogen peroxide can damage cells.

Lysosomes As Gatekeepers: How Lic1-Mediated Trafficking Regulates Angiogenesis And Vascular Morphogenesis, Dymonn Johnson

Arts & Sciences Graduate Student Theses and Dissertations

Dynein cytoplasmic 1 light intermediate chain 1 (LIC1, DYNC1LI1) is a core subunit of the dynein motor complex that plays a critical role in cytoplasmic cargo trafficking, including Rab-mediated endosomal recycling and lysosomal degradation. LIC1 interacts with various cargo adaptors, such as RILPL1 and RILPL2, to regulate these processes, and defects in this gene are predicted to impair dynein motor function, Rab binding, and lysosomal trafficking. Here, we identified a dync1li1 zebrafish mutant with a premature stop codon at the exon 12/13 splice acceptor site, that exhibits increased angiogenesis. In vitro, LIC1-deficient human endothelial cells show elevated cell surface levels …

Application And Comparison Of Satellite-Derived Sea Surface Temperature Gradients To Identify Seasonal And Interannual Variability Off The California Coast: Preliminary Results And Future Perspectives, Jorge Vazquez-Cuervo, Marisol García-Reyes, David S. Wethey, Daniele Ciani, Jose Gomez-Valdes

Faculty Publications

The application of satellite-derived sea surface temperature in coastal regions is critical for resolving the dynamics of frontal features and coastal upwelling. Here, we examine and compare sea surface temperature (SST) gradients derived from two satellite products, the Multi-Scale Ultra-High Resolution SST Product (MUR, 0.01° grid scale) and the Operational SST and Ice Analysis (OSTIA, 0.05° grid scale), available through the Group for High Resolution SST (GHRSST). Both products show similar seasonal variability, with maxima occurring in the summer time frame. Additionally, both products show an increasing trend of SST gradients near the coast. However, differences exist between the two …

Radioactive Contamination And Climate Warming Affect Physiological Performance Of Chornobyl Barn Swallows, Zbyszek Boratyríski, Timothy Mousseau, Anders Pape Møller

Faculty Publications

Global warming and degradation of natural habitats are the two main factors causing ecophysiological stress on individuals and risk for biodiversity. Hyperthermia is a common response to stress in homeothermic animals, in particular to heat, pathogens and environmental contamination. Resilience of biological systems to global warming may be deteriorated in polluted habitats. Here we investigated how body temperature of a wild bird, the barn swallow (Hirundo rustica), responded to global warming while simultaneously exposed to radioactive contamination from the Chernobyl accident. Our results showed that both high air temperatures (t = 15.55, df = 335, p <  0.0001) and elevated environmental radioactive contamination (t = 5.18, df = 8.09, p = 0.0008) increased internal body temperature of individuals. The additive effect suggests that birds might suffer hyperthermia in locally contaminated habitat (1.47% body temperature increase) while simultaneously exposed to globally rising temperatures (1.95% body temperature increase), potentially reducing the fitness of individual and the maintenance of breeding colonies. The cumulative and interactive negative effects of multiple stressors, such as those emerging from increasing habitat degradation and climate change, will likely contribute to biodiversity losses globally.