Biology Commons^™

Substantial Contribution Of Woody Components To Rainfall Interception In Chinese Forests: Insights From A Refined Analytical Model, Zhi-Ang Chen, Zhi-Yun Jiang, Wei He, John T. Van Stan Ii, Et. Al.

Biological, Geological, and Environmental Faculty Publications

Assessing rainfall interception (I-R) is a critical yet uncertain aspect in hydrological cycle, particularly the quantification of relative contributions from leaves and woody components (e.g., branches, stems, and trunks) to I-R. Nevertheless, the role of woody components in I-R estimation remains largely unexplored and thereby has been constantly overlooked. This study addressed this challenge and refined the widely-used Gash model to distinguish woody interception (I-W) from leaf interception (I-L). We incorporated the spatial variability of vegetation traits alongside satellite data in 2019 into the refined model, and spanned China's major forest types. The refined model showed a strong agreement with …

Immunoglobulin Germline Reference Sequences Enable Investigations And Reveal Insights Into Bat-Specific Immunity, Ashley B. Reers, Shijun Zhan, Taylor Pursell, Clara Reasoner, Natasha Hodges, Tanya M. Lama, Tony Schountz, Hannah K. Frank

Biological Sciences: Faculty Publications

We generated a highly contiguous, annotated genome of the Jamaican fruit bat, Artibeus jamaicensis, including annotated germline immunoglobulin heavy-chain (IGH) and light-chain lambda (IGL) loci to understand bat B cell receptor repertoires. The bat germline shares many structures and features described in human immunoglobulin loci. However, some features are unique to A. jamaicensis, including an expansion of cysteine-rich IGHV genes. To investigate the relationship between the germline IGH locus and expressed B cell receptors (BCRs), we sequenced the BCRs of wild-caught and captive A. jamaicensis, finding an enrichment of IGHV3 and IGHV4 genes. Compared to humans, A. jamaicensis had shorter …

Public Perception About Covid-19 Vaccine Hesitancy In South Central Nebraska, Rita Nnenne Oparaocha

Biology Theses, Dissertations, and Student Creative Activity

The COVID-19 pandemic created a shift in the trajectory of vaccination hesitancy, altering risk perceptions and vaccination attitudes among individuals in rural communities. The 5C framework highlights confidence, complacency, constraints, calculation, and collective responsibility as influencing factors of vaccine hesitancy. This study assessed the proportion of adults who refused COVID-19 vaccination and identified the individual reasons for hesitancy among those who refused the COVID -19 vaccines in South Central Nebraska. Data was analyzed from a local cross-sectional public health survey administered to 2,034 adult participants over a six-month period (March-August 2024), including 91 respondents who were from outside the seven-county …

Comparisons Of Fish Communities Between A Restored And A Control Pool Of The Mississippi River: A Before-And-After Examination, Hannah Lenning

Biology Theses, Dissertations, and Student Creative Activity

The quality and availability of valuable backwater habitats have declined in many rivers, including the Upper Mississippi River (UMR), due to river modifications and land use change. Habitat Rehabilitation and Enhancement Projects (HREPs) are implemented by the Upper Mississippi River Restoration Program and often aim to mitigate accelerated sedimentation and degradation of backwater habitats. One HREP in Pool 12 of the UMR targeted overwintering fish habitat by restoring four backwaters within 14 RKM. Fish community data was collected before (2006-2012) and after (2020-2024) restoration in Pool 12 and a downstream, control reach, Pool 13. The first objective of my study …

A Genetic Interaction Between Ded1 And Hat1 In Saccharomyces Cerevisiae Reveals A Role For Hat1p In Cytoplasmic Rna Granule Accumulation, Audrey J. Panko, Aidan Winters, Nicholas R. Rothbard, Angela K. Hilliker

Biology Faculty Publications

Ded1p is an essential translation initiation factor that interacts with and is modulated by eIF4F. Ded1p also promotes the assembly and disassembly of stress granules, which contain nontranslating mRNAs and translation initiation factors. As Ded1p affects both mRNA storage and translation initiation, regulation of Ded1p's function may affect whether mRNAs are translated or localized to cytoplasmic RNA granules. To identify regulators of Ded1p in Saccharomyces cerevisiae, we screened for overexpression suppressors of the severe growth defect conferred by high levels of Ded1p. We found that overexpression of HAT1, a lysine acetyltransferase, can suppress the growth defect conferred by …

Elucidating The Role Of Hd5 In Colonic Wound Healing, Lavin Radiro

Student Scholar Symposium

Crohn’s colitis (CC), a subtype of inflammatory bowel disease (IBD), causes chronic inflammation in the large intestine, leading to malnutrition, diarrhea, and severe pain. Early and accurate diagnosis of CC is crucial, as misdiagnosis with ulcerative colitis (UC) can result in inappropriate treatment and worsened outcomes. The innate immune peptide human alpha-defensin 5 (HD5) is upregulated in CC but not in UC, suggesting a potential role in disease pathogenesis. Preliminary data from our lab indicates that HD5 impairs wound healing in colonic epithelial cells, but the molecular mechanisms remain unclear.

Hypothesis We hypothesize that HD5 increases RNA and protein levels …

Investigating The Potential Ability Of The Tlr4-Nf-Κb Axis To Reduce Aryl Hydrocarbon Receptor Expression In Intestinal Epithelial Cells, Gabriella Longoria

Student Scholar Symposium

Necrotizing enterocolitis (NEC) primarily affects premature infants and is characterized by intestinal necrosis, inflammation, and high mortality. Toll-like receptor 4 (TLR4)-induced apoptosis of intestinal epithelial cells is thought to drive NEC development. Upon binding bacterial lipopolysaccharide (LPS), TLR4 signaling activates NF-κB, leading to inflammatory gene expression. Indole-3-carbinol (I3C), a pro-ligand of the aryl hydrocarbon receptor (AhR), prevents NEC in a mouse model by downregulating TLR4, despite reduced AhR expression in NEC-affected intestines. However, the molecular mechanism behind the reduced expression of AhR in NEC is unclear. To model NEC in vitro, we treated IEC-6 enterocytes with LPS, which reduces AhR …

Investigating The Role And Mechanism Of Faecalibacterium Prausnitzii In Fatty Acid Metabolism And Obesity Using The Drosophila Melanogaster Model, Jackson Head, Whitley Whitehead

Student Scholar Symposium

The obesity epidemic has increased to enormous numbers with 890 million adults being classified as obese (BMI≥30). Obesity is of extreme concern as it is a comorbidity to coronary heart disease, type-2 diabetes, and cancer. Although obesity has classically been attributed to genetics and lifestyle, there is a growing interest in other factors, including the gut microbiome. Germ-free mice are resistant to weight gain even when placed on a high-calorie diet, establishing that metabolites produced by gut microbiota can dramatically inhibit metabolism. Here, we use Faecalibacterium prausnitzii, which has been previously shown to be reduced in obese individuals; however, …

Indole Improves Outcomes Of Cronobacter Sakazakii Infection In C. Elegans Through Ahr-1, Cayden Durrough

Student Scholar Symposium

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease primarily affecting premature infants. Toll-like receptor 4 (TLR4)-mediated epithelial damage allows microbial translocation, triggering inflammation that can lead to sepsis and death. The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor, and AhR ligands have been shown to prevent NEC in a mouse model. Indole, an AhR ligand, has been reported to extend the healthspan of C. elegans, and we have shown previously it mitigates poor outcomes in wild-type worms infected with Cronobacter sakazakii (Cs), a bacterial pathogen linked to NEC. We hypothesized that C. elegans must express ahr-1, the ortholog …

Indole Treatment Of C. Elegans Rescues Cronobacter Sakazakii Induced Illness, Joshua Asselin

Student Scholar Symposium

Necrotizing enterocolitis (NEC) is a severe and often life-threatening inflammatory condition of the intestine primarily affecting premature infants. The opportunistic pathogen Cronobacter sakazakii (Cs) has been implicated in NEC. While activation of the ligand-dependent transcription factor aryl hydrocarbon receptor (AhR) has been shown to prevent NEC in a mouse model, its potential as a therapeutic target for established NEC remains unclear. We hypothesize here that the AhR ligand indole can reverse Cs-mediated illness in the model organism Caenorhabditis elegans. Our results demonstrate that exposure to live Cs, but not heat-killed Cs, significantly impaired worm motility, demonstrating Cs is an effective …

Function Of Drosophila Melanogaster Domesticated Transposable Element Protein Dplg3 In Oogenesis And Total Fitness, Aron Herrera

2025 Fall Honors Capstones Projects - Archive

Transposable elements (TEs) are selfish DNA segments capable of self-replication and reinsertion within genomes, often harming hosts. Rarely, host genomes can adopt TEs and use their proteins for new cellular functions through molecular domestication. One example primarily expressed in Drosophila melanogaster ovaries is DPLG3. Previous Betrán Lab students generated DPLG3 loss-of-function flies and found that their ovaries misregulated one primordial and 14 testis-specific genes, leading to variable ovarian malformations. However, it is unclear when during oogenesis these misexpressions occur. We will extract RNA from non-rudimentary ovaries at early and late stages to generate cDNA for qRT-PCR analysis of three …

Impact Of Gas Supersaturation On The Development Of Gas Bubble Trauma In Paedomorphic Eurycea Salamanders, Trent Furr

Biology Theses

There are eleven species of paedomorphic lungless salamanders endemic to Texas. Of these, eight are considered threatened by the International Union for Conservation of Nature (IUCN). One of these, the Barton Springs Salamander (Eurycea sosorum), is found only in springs and aquifers in and around Austin, Texas. A large population of this species is found in Barton Springs, located in Austin, TX–where dissolved gas saturation has been measured as high as 134%. Morbidity and mortality events in Barton Springs Salamanders have been documented coinciding with periods of dissolved gas supersaturation. This study seeks to understand what environmental conditions lead to …

Understanding Pancreatic Islet Stress Responses And Developing Strategies To Improve Transplantation Grafts, Marlie Maria Maestas

Arts & Sciences Graduate Student Theses and Dissertations

Diabetes mellitus is a chronic metabolic disorder affecting millions worldwide, characterized by hyperglycemia resulting from defects in insulin secretion or action. While current treatments range from pharmacotherapy to experimental cell-based therapies, progress remains hampered by donor scarcity and an incomplete understanding of islet stress responses. This dissertation investigates cellular stress responses in pancreatic islets and strategies to improve stem cell-derived islet (SC-islet) transplantation. The first chapter provides an overview of diabetes pathophysiology, modeling approaches, and treatment options. In the second chapter, we use single-cell RNA sequencing to investigate cell-type-specific responses to diabetes-associated stress in primary human islets exposed to endoplasmic …

Understanding The Role Of Hd5 In Colonic Epithelial Cell Death, Maryam M. Gerges, Amanda D. Williams

Student Scholar Symposium

Inflammatory bowel disease (IBD) is an autoimmune disorder where the immune system attacks healthy tissue. IBD can occur in both adults and children, describing Ulcerative Colitis (UC) and Crohn’s Colitis (CC). Our lab studies human alpha defensin 5 (HD5), an antimicrobial peptide that normally maintains small intestinal sterility. However, in CC patients, HD5 is overexpressed in the colon. Preliminary data suggests that HD5 increases colonic cell death. This project aims to determine if HD5 induces apoptosis and its mechanisms. To this end, we will test if the suppression of caspase enzymes with a pan-caspase inhibitor reduces cell death triggered by …

Impact Of Zar1l Expression On Drug Response In Breast Cancer Cells, Maryam M. Gerges, Smita Misra

Student Scholar Symposium

Breast cancer (BC) is the most common cancer in women worldwide and the second leading cause of cancer-related deaths among females. BC arises from the uncontrolled proliferation of breast epithelial cells. A crucial gene associated with BC is the Breast Cancer Susceptibility Gene 2 (BRCA2), a tumor suppressor that aids in DNA repair. Proper BRCA2 function helps prevent BC. Our lab studied the cell cycle-dependent expression of BRCA2 revealing that its promoter exhibits bi-directional activity. During cell division, forward activity transcribes BRCA2, while in the resting phase, reverse activity transcribes ZAR2 (Zygote Arrest 1 Like). ZAR2, an RNA-binding protein with …

The Role Of Human Alpha Defensin 5 (Hd5) In Disrupted Wound Healing Processes In Crohn’S Colitis, Jafer Aljorani, Amanda Williams

Student Scholar Symposium

Wound healing is a complex biological process requiring the coordinated function of multiple proteins. In chronic inflammatory bowel disease (IBD), particularly Crohn’s Colitis (CC), this process is dysregulated, leading to delayed tissue repair and increased disease burden. Prior studies indicate that Human Alpha Defensin 5 (HD5) is over-expressed in the colonic epithelium of CC patients, yet its impact on wound healing remains poorly understood. Our laboratory has identified that HD5 may impair wound healing by modulating key structural and regulatory proteins. Preliminary findings suggest that HD5 reduces the expression and function of desmoplakin, a critical desmosomal protein essential for maintaining …

Functionality Of The Ryanodine Receptor Type 1 (Ryr1) In The Development Of Malignant Hyperthermia (Mh), Cesar Medina, Joshua Owens

Student Scholar Symposium

Malignant Hyperthermia (MH) is a rare but potentially lethal pharmacogenetic disorder, affecting roughly 1 in 30,000 children and 1 in 100,000 adults undergoing surgery. MH can be triggered by agents used for general anesthesia. These may include volatile anesthetics such as sevoflurane, isoflurane, desflurane, halothane or depolarizing neuromuscular blockers such as succinylcholine. Upon administration of a trigger, an MH susceptible (MHS) patient can develop a hypermetabolic state during the intraoperative or postoperative periods. If not treated quickly, an MH episode could result in organ dysfunction or death. The primary mechanisms involved in the development of an MH crisis include the …

Her2 Amplification In Breast Cancer And Its Treatment Options, Emerald Cole, Zoe Grace Brigance

Student Scholar Symposium

Breast cancer affects approximately 2.3 million women worldwide, causing an estimated 670,000 deaths in 2022. Among its subtypes, 15-20% exhibit overexpression of Human Epidermal Growth Factor Receptor 2 (HER2), a tyrosine kinase receptor that drives tumor aggressiveness. HER2 activates the PI3K and RAS/RAF/MAPK pathways, promoting uncontrolled cell growth, proliferation, and survival. In HER2+ breast cancer, gene amplification leads to excess HER2 protein production, resulting in persistent signaling and unchecked tumor progression. However, this dependency on HER2 presents a key therapeutic opportunity. Trastuzumab, an anti-HER2 monoclonal antibody, inhibits HER2 signaling and enhances immune-mediated cancer cell destruction. When combined with Lapatinib, chemotherapy, …

The Effect Of Diet On Hydrogen Sulfide Tolerance Of Extremophile Fishes, Kyliyah Walker, Michael Tobler, Bethany Williams

Undergraduate Research Symposium

Poecilia mexicana are a species of live-bearing fish that have adapted to surviving in hydrogen sulfide (H₂S) abundant waters. Sites that are high in toxic H₂S are also characterized by low levels of oxygen, making any organism that inhabits these tough conditions to be deemed extremophiles. Tolerance of these multiple stressors is impacted by numerous external environmental factors. The question being addressed in this study is if diet affects how well these fish tolerate H₂S. I used 80 laboratory-bred female P. mexicana originating from two sulfidic and non-sulfidic population. Half of the fish from …

Measuring Welfare Of Wild Tarantulas During Field Surveys Using Heart Rate, Tim Angelo Artiaga Lopez, Becky Hansis-O'Neill, Aimee Dunlap Phd

Undergraduate Research Symposium

Tarantulas (Theraposidae) are predatory arachnids that can help control populations of herbivorous arthropods. We have been monitoring populations of the Missouri brown tarantula (Aphonopelma hentzi) in Missouri glades for three seasons and have questions about their welfare during these surveys. Unlike mammals, arthropods are not extensively researched and there are only a few known facts about measuring their welfare. Managing stress for wild animals during field surveys is important for reducing the potential negative impacts of research. In mammals, increased heart rate is positively correlated with negative stress and eustress. Using the same logic, we hypothesized that heart rate could …

Phenotypic Variations Between The European Paper Wasps, Senna V. Horak, Thomas Hagan, Sara Miller

Undergraduate Research Symposium

The European paper wasp (Polistes Dominula) is a widespread invasive Hymenoptera species in the US, commonly known for their black and yellow markings. Phenotypic variations, primarily in color patterns and size, play a significant role in understanding their interactions among other wasps and effects of environmental factors on the species. In this study, we examined phenotypic variation within and between populations by measuring head width, intertegular distance, and femur and tibia length.

Habitat Disturbance And Biodiversity In Glade Habitats, Maddie Smith, Becky Hansis-O'Neill, Aimee Dunlap Phd

Undergraduate Research Symposium

The Ozark glades are home to a variety of reptiles, amphibians, rodents, and invertebrates such as tarantulas and scorpions. Glade inhabitants face challenges like habitat fragmentation and degradation, but they could be facing even bigger challenges as outdoor recreation becomes more popular. People looking for wildlife to photograph or collect often look under rocks without leaving them how they were found. This study focused on monitoring rock disturbance at two protected glades- Shaw Nature Preserve and a more accessible undisclosed glade in Jefferson County. Disturbing the glade habitat to look for wildlife is prohibited at both sites. Twenty rocks at …

Targeting Pancreatic Cancer With Rapamycin-Loaded Gold Nanoparticles Conjugated To Egf Peptide: Studies On Cytotoxicity And Uptake Mechanisms Aided By Proteomic Analysis, Adeolu Oluremi

Theses and Dissertations

Pancreatic cancer remains one of the most lethal malignancies, with a five-year survival rate below 5%. While rapamycin (Rap) has demonstrated therapeutic potential, its clinical utility is hampered by systemic toxicity. To address this limitation, this study developed a targeted nanocarrier system using gold nanospheres (AuNPs) functionalized with the Epidermal Growth Factor Receptor (EGFR) peptide GE11 for the specific delivery of Rap to pancreatic cancer cells. It is to note that pancreatic cancer overexpresses EGFR. The AuNP–GE11–Rap conjugates were successfully synthesized and characterized using physico-chemical techniques, which confirmed peptide conjugation and drug loading. In vitro studies using PANC-1 cells demonstrated …

Synteny To Snps: Comparative And Population Genomics Of Endemic Gila River Fishes, Alexander C. Cameron

Biology ETDs

Population genomic data are becoming an essential component of the best available science used by conservation professionals to make management decisions to preserve biodiversity in a rapidly changing world. The proliferation of high-throughput sequencing technologies has made generating genome scale data feasible for non-model organisms that are of conservation concern. In addition to applicability in conservation science, genomic data enable the exploration of basic questions related to species evolution. To that end, this body of research exemplifies the applied and basic utility of genomic data and is focused on two federally-protected minnows endemic to the Gila River basin, Loach Minnow …

Cv: Sarah Powers (Biology), Sarah Powers

Biology Department Faculty Curricula Vitae

No abstract provided.

Rab32c Mediates Osmoregulation And Calcium Homeoastasis In Dictyostelium Discoideum, Ashley Esparza

Theses and Dissertations

Vesicular trafficking is a fundamental process essential to cell viability and dictates roles in both cellular and tissue function in multicellular organisms. To further understand various vesicular trafficking processes, our lab focuses on the moderators of these processes, Rab GTPases, using the model organism Dictyostelium discoideum. This dissertation focuses explicitly on the uncharacterized protein Rab32C, a homolog of human Rab32. While several Rab family members have been well defined, the functionality of Rab32C remains poorly understood. This project investigated both the subcellular localization and functional role of Rab32C with biochemical, imaging, and molecular assays. Results from this study provide evidence …

Functional And Microbial Consequences Of Experimental Evolution Under Starvation In Drosophila Melanogaster, Kristal Marie Aguilar-Conger

UNLV Theses, Dissertations, Professional Papers, and Capstones

Previous studies in the Gibbs lab have shown that starvation resistant Drosophila melanogaster flies have increased lipid content, lower metabolic rates, and poor physiological health. Historically, many evolutionary studies end at the phenotypic level, leaving the genomic basis largely unresolved. Using Evolve and Resequence (E&R) study, we can map genome-wide allele-frequency trajectories under selection, linking phenotypic shifts to their genomic underpinnings. This study utilized the E&R approach to identify enriched biological processes and pathways underlying starvation adaptation in Drosophila melanogaster. Five replicate restart populations (RS A–E) selected for starvation resistance, along with a control (RC), were resequenced at Generations 1, …

Enviromental Dna (Edna) Tools For Invasive Mosquitofish (Gambusia Affinis) Surveillance At The Shoshone Pupfish (Cyprinidon Nevadensis Shoshone) Refugium, Yusuf Olamilekan Umar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spring-fed aquatic ecosystems of the North American Southwest and U.S. Great Basin hosts a plethora of endemic fish species due to the effects of hydrologic fragmentation that resulted from Pleistocene aridification. Threats to endemic fishes worldwide include human intentional or unintentional release of exotic species into their habitats. Early detection of invasive species, while corrective actions are still possible, is critical for management, yet traditional survey methods are often disruptive to sensitive ecosystems, costly, and limited in sensitivity. The recent development of environmental DNA (eDNA) approaches offers powerful alternatives for invasive species monitoring in aquatic systems. In this study, a …

Elucidating The Role Of Pbaf Chromatin Remodeling Subunit Arid2 In B Cell Development, Rachel Paolini

Arts & Sciences Graduate Student Theses and Dissertations

B cells are key components of the adaptive immune system that mediate humoral immunity through the production of antigen-specific antibodies. The generation of functional B cells involves multiple stages of differentiation across distinct anatomical niches, requiring precise regulation of microenvironmental signals and intrinsic transcriptional networks. SWI/SNF chromatin remodeling complexes have emerged as key regulators of B cell lineage commitment by modulating the accessibility of transcriptional programs required for differentiation and maturation. However, the specific roles of individual SWI/SNF subunits and distinct complexes within early B cell differentiation remain poorly understood. In this thesis, I investigated the function of Arid2, an …

Protocols For Antioxidant Testing: A Mini Review Of Common Assays And Approaches, Abdulsalam Halboup, Sameer A. Alkubati

AUIQ Complementary Biological System

Antioxidants play a pivotal role in mitigating damage caused by oxidative stress, which is implicated in aging, inflammation, neurodegeneration, and various chronic diseases. With the growing interest in natural and synthetic antioxidants across nutraceutical, pharmaceutical, and food industries, the need for reliable, reproducible, and standardized testing methods has become increasingly urgent. This mini-review provides a structured overview of the most widely used antioxidant testing protocols, categorized into in vitro chemical-based assays (e.g., DPPH, ABTS, FRAP, metal chelation), cell-based assays (e.g., DCFH-DA for intracellular ROS detection), and in vivo biomarker-based models. Each method’s principle, experimental protocol, advantages, and limitations are critically …