Biology Commons^™

Optophysiology Of D. Melanogaster Neuromuscular Synapses Using Gcamp, Kavindra Dasrat

Biological Sciences

An activity-dependent increase in postsynaptic currents produced by a single vesicle of neurotransmitter is an important mechanism for synaptic plasticity in the central nervous system (CNS) and possibly involved in learning and memory. We have found a similar form of postsynaptic potentiation at the D. Melanogaster neuromuscular junction (NMJ) where a brief increase in impulse activity results in an increase in the amplitude of spontaneous miniature excitatory postsynaptic currents (mEPSCs), resulting in miniature excitatory postsynaptic potentials (mEPSPs). To visualize sites of postsynaptic potentiation along the synaptic terminal, we have used a Ca2+ indicator, GCaMP to observe postsynaptic Ca2+ signals. Since …

Investigating The Roles Of Rna Modification And Associated Enzymes On Stress Response And Connections To Human Diseases, Carrson Widen

Biological Sciences

Transfer RNAs decode messenger RNA using anticodon – codon interactions to deliver specific amino acids to a growing peptide chain. Enzyme-catalyzed modifications on specific nucleotides on tRNAs increase their stability and help mediate the speed and fidelity of translation, giving these modifications regulatory potential. RNA modifications are catalyzed by writer enzymes, and I predicted that writers are important in the cellular responses to stress. I have evaluated the following E. coli modification enzyme mutants: miaA, mnmE, dtd, tmcA, lysU, yeaK, and iscS, from the corresponding Keio E. coli gene deletion library. Writer mutants were exposed to hydrogen peroxide to induce …

Regaining Effort-Based Food Motivation: The Drug Methylphenidate Reverses The Depressive Effects Of Tetrabenazine In Female Rats, Deanna Pietrorazio

Honors Scholar Theses

Tetrabenazine (TBZ), a vesicular monoamine transporter type 2 (VMAT-2) inhibitor, depletes dopamine and induces motivational deficits and other depressive symptoms in humans. Methylphenidate (MPH) is a dopamine transport blocker that is used to enhance motivational function. Previous studies have shown that in male rats, TBZ induces a shift in effort-related choice such that a low-effort bias is induced. In male rats this occurs at a dose range of 0.75-1.0 mg/kg TBZ, and this effect is reversible with co-administration of MPH. Recent studies have shown that females need a higher dose of TBZ (2.0 mg/kg) to show the low-effort bias. The …

Alterations Of The Gut Mycobiome In Patients With Ms - A Bioinformatic Approach, Saumya Shah

Honors Scholar Theses

The mycobiome is the fungal component of the gut microbiome and is implicated in several autoimmune diseases. However, its role in multiple sclerosis (MS) has not been studied. We performed descriptive and formal statistical tests using the R language to characterize the gut mycobiome in people with MS (pwMS) and healthy controls. We found that the microbiome composition of multiple sclerosis patients is different from healthy people. The mycobiome had significantly higher alpha diversity and inter-subject variation in pwMS than controls. Additionally, Saccharomyces and Aspergillus were over-represented in pwMS. Different mycobiome profiles, defined as mycotypes, were associated with different bacterial …

Effects Of Tributyltin Exposure On 8-Ohdg And Dsdna Expressions, Oxidative And Nitrative Stress In The American Oyster, Crassostrea Virginica, Mohan Kumar Dash

Theses and Dissertations

Environmental pollution increases due to anthropogenic activities. Different types of pollutants and/or chemicals impair growth, reproduction and development in aquatic organisms. Tributyltin (TBT, an organotin compound) is a tremendously toxic substance which widely uses as antifouling paints used in boats, hulls, and ships. The toxic effect of TBT is well documented in teleost species. The American oyster (Crassostrea virginica) is an ideal shellfish species to study on TBT exposure DNA lesion and oxidative/nitrative stress. In this study, the effects of TBT on 8’-hyrodxy-2’-deoxyguanosine (8-OHdG, a molecular marker), dsDNA, dinitrophenyl protein …

Identification Of Sall4 Expressing Islet-1+ Cardiovascular Progenitor Cell Clones, Andrea Gabrielle Monteon

Electronic Theses, Projects, and Dissertations

The utilization of cardiac progenitor cells (CPC) has been shown to induce favorable regenerative effects. While there are various populations of endogenous CPCs in the heart, there is no consensus regarding which population is the most ideal for cell-based regenerative therapy. Identifying an Islet-1+ (Isl-1+) early-stage progenitor population with enhanced stemness, multipotency and differentiation potential would be beneficial for regenerative therapy. Spalt-like transcription factor 4 (SALL4) plays a role in embryonic development as well as proliferation and expansion of hematopoietic progenitor cells. We hypothesize that SALL4 will be co-expressed in Isl-1+ cardiac progenitor cell clones isolated from human cardiac tissue …

Modulation Of Kras Structure And Dynamics By Kras Ubiquitination And Membrane Depolarization, Vinay Nair

Dissertations and Theses (Open Access)

KRAS, a 21 kDa small GTPase protein, functions as a molecular switch playing a key role in regulating cell proliferation. Dysregulation of KRAS signaling by oncogenic mutations leads to uncontrolled cell proliferation, a hallmark of cancer cells. Attempts to therapeutically target oncogenic KRAS have led to limited success resulting in a need to identify new mechanisms to targeting KRAS. The interaction of KRAS with its regulators, effectors, and the membrane present one such avenue. In this study, we investigated how post-translational covalent and environmental modifications could modulate these interactions of KRAS. Using computational molecular dynamics simulations, nuclear magnetic resonance spectroscopy …

Investigation Of Genomic Instability Induced By G-Quadruplexes In The Absence Of Functional To Poisomerase 1 In Yeast, Alexandra Berroyer

Dissertations and Theses (Open Access)

Topoisomerase 1 (Top1) is an enzyme that removes transcriptionally generated negative supercoils by binding and nicking DNA. Since transcription of guanine-rich DNA leads to the formation of G-quadruplex (G4) structures, Top1’s function likely suppresses G4-formation. In support of this, Top1 significantly reduces co-transcriptional G4 DNA-associated genomic instability at a model G4-motif in Saccharomyces cerevisiae. However, whether Top1 suppresses G4-formation on a genome-wide scale in yeast remains unexplored. Therefore, I aimed to uncover if deletion of Top1 enhances genome-wide G4-formation in S. cerevisiae. As an approach to quantify global G4-formation, I expressed the G4-specific antibody BG4 from a yeast …

Invisible Disabilities, Academic Capital And Competitiveness Of Genetic Counseling Applicants, Natalie E. Stoner, Meagan Choates, Carla Mcgruder, Debra Murray, Theresa Wittman, Sara Wofford, Claire N. Singletary

Dissertations and Theses (Open Access)

The field of genetic counseling has historically lacked diversity. Recent research has begun to explore how visible diversity may present barriers to a genetic counseling applicant becoming competitive, but has not yet characterized potential barriers with invisible diversities, such as being a first-generation college student, or a part of the LBGTQ+ community. Therefore, this study aimed to address this gap among those with invisible diversities, as well as explore their academic capital (AC), a theoretical framework used to identify factors that make students more likely to succeed in post-secondary work including supportive networks, trustworthy information, family uplift, college knowledge, overcoming …

Computational Approaches To Understand Chemoresistance & Tumor Evolution Using Longitudinal Clinical Data And Lineage Tracing, Sahil Seth

Dissertations and Theses (Open Access)

Tumors are highly heterogeneous and dynamic, continually adapting and evolving in response to their microenvironment as well as external perturbations. Multi-region (spatial) and single cell sequencing has enabled us to anatomize the heterogeneity further and provide evidence of its association with chemo and drug resistance. To investigate this further we took two different approaches to understand the chemo-resistance, and functional heterogeneity in Triple negative breast cancer (TNBC) and Pancreatic ductal carcinoma in situ (PDAC) from an evolutionary perspective.

The first approach was to leverage tumor profiling from an ongoing randomized clinical trial in triple-negative breast cancer (ARTEMIS) to assess mechanisms …

At-Home Yogurt Making To Investigate Microbiology Concepts: A Remote Biology Laboratory, Tatiana Kuzmenko, Jacqueline Raetz-Vigon, Demian A. Willette

Biology Faculty Works

The global COVID-19 pandemic has forced many educators to move their courses to the online environment with little time to adjust. It especially affected undergraduate biology laboratory courses that rely on on-campus facilities to provide students with meaningful laboratory-type experiences. Here we describe a multisession, at-home, and hands-on laboratory activity that utilizes yogurt culturing to explore microbiology concepts. We also summarize the findings of 219 undergraduate students who successfully performed this lab remotely. In small virtual groups, students learned how to make yogurt at home, formulate a testable hypothesis, run an experiment on conditions necessary for yogurt fermentation, analyze experimental …

Epidemiology And Impacts Of A Leaf Spot Disease In Veratrum Viride (Melanthiaceae), Leeah R. Sutton, Foster Levy

Undergraduate Honors Theses

Fungal phytopathogens can cause disease epidemics in crops, weeds, and
populations of native plants. To investigate the impact of a foliar phytopathogen on the native herbaceous species, Veratrum viride, a demographic and disease assessment was carried out on two high elevation grassy bald populations on Roan Mountain, Tennessee. A leaf spot disease impacted all plants in both populations, causing widespread premature senescence of leaves and stems. Disease severity increased over the course of the growing season. Based on host disease symptoms and fungal conidia morphology, Pseudocercosporella sublineolata was shown to be the causal pathogen. A study of herbarium specimens …

The Impacts Of Holocene Climate And Pre-Columbian Humans On Neotropical Andean Forests, Rachel Kathleen Sales

Theses and Dissertations

Humid montane forests in the tropical Andes form hotspots for biodiversity, endemism, and conservation. Threats to the forests from deforestation are amplified by ongoing climate change, which could further reduce available habitat area by about 57 – 80%. These forests are known to have withstood considerable climate change in the past, and an emerging view suggests that they have also been shaped by a long interaction with people. Although climate-driven species range shifts are broadly known, questions remain about how past climate change has affected the species composition of these forests. The interaction of people with forests on the eastern …

The Form And Function Of Cranial Spines In Fishes, Louis Michael Penrod

Theses and Dissertations

Despite the prevalence of fishes that express cranial spines, quantitative investigations into the function of these spines are rare. Function is often assumed with little or no evidence. Commonly, spine-like structures are considered to be used for defense despite spines potentially being used for other purposes. Here, I took a high-level approach to investigate the morphology and potential functions of cranial spines in over 2000 fishes. Identifying the function of cranial spines in fishes not only informs us as to how these fishes interact with conspecifics, with other species, and with their environment, but also may provide advances in human …

Evaluating Methods To Determine The Maximum Oxygen Consumption By The Gulf Killifish, Fundulus Grandis, Sylvia Mullen

Senior Honors Theses

Metabolic rate is an essential feature of animal physiology and ecology. The rate of aerobic metabolism, as determined by oxygen consumption rate (MO2), is influenced by a variety of factors, including body size, temperature, and activity levels. Maximum aerobic metabolic rate (MMR) reflects the physiological capacity of an animal for oxygen extraction and utilization. As such, MMR is argued to be an important feature of an animal’s life history. For fish, MMR is frequently estimated as the peak MO2 immediately following an exhaustive chase, although several studies indicate that this value may underestimate MMR. Rather, MMR may be attained during …

Mathematical Modeling Of Potassium Modulated Viral Infection, Zaira Elizabeth Mather

Open Access Theses & Dissertations

In recent years, there is a growing interest in the investigation of using potassium to treat virus infections. In the region of infection, there is a biological observation of extracel- lular potassium level being typically very low whereas the intracellular potassium levels are much higher. There are numerous biological studies showing that elevated potassium levels in the extracellular membrane tends to block virus infections. A recent effort in this direction is a collaborative research conducted by mathematicians and biologists from the University of Texas at El Paso, New Mexico State University, and the University of New Mexico, where we develop …

Ciliate Endosymbiont Imaging Methodology, Aidan Boving, Roxanne Beinart

Senior Honors Projects

Ciliates, a phylum of diverse microbial eukaryotes, are found in a wide range of environments, including anoxia. Anaerobic ciliates host intracellular methanogenic archaea – a unique type of symbiosis. Despite their importance, anaerobic ciliates and their symbiotic relationships remain understudied. Included in this is the ability to image and quantify the intracellular methanogenic symbionts in a precise, timely and replicable procedure. This project aimed to improve the current fluorescence microscopy methodology used for endosymbiont quantification. The proposed method is intended for use with the Opera Phenix, a high throughput spinning disk confocal microscope which can count large amounts of individual …

Wildlife Associates Of Nine-Banded Armadillo (Dasypus Novemcinctus) Burrows In Arkansas, Brett A. Degregorio, John T. Veon, Andrhea Darleen Massey

Biological Sciences Faculty Publications and Presentations

The Nine-banded Armadillo (Dasypus novemcinctus) is a widespread burrowing species with an expanding geographic range across the southeastern and midwestern United States. Armadillos dig numerous, large burrows within their home ranges and these burrows are likely used by a diverse suite of wildlife species as has been reported for other burrowing ecosystem engineers such as Gopher Tortoises (Gopherus polyphemus), Desert Tortoises (Gopherus agassizi), and Black-tailed Prairie Dogs (Cynomys ludovicianus). We used motion-triggered game cameras at 35 armadillo burrows in 4 ecoregions of Arkansas and documented 19 species of mammals, 4 species of …

Impact Of Genetic Variation And Timescale On Diatom Salinity Stress Response, Kala M. Downey

Graduate Theses and Dissertations

Natural environments are dynamic, and organisms must sense and respond to changing conditions. One common way organisms deal with stressful environments is through gene expression changes, allowing for stress acclimation and resistance which occurs over varying time spans in different species. The recent evolutionary history of populations could greatly influence their ability to respond successfully. An evolutionary history in disturbed or fluctuating conditions could promote increased resistance or a more rapid response to these environmental stressors. To understand the impact of genotypic variation and timescales on response and acclimation to salinity changes, we have been exploiting the abilities of euryhaline …

The Use Of Hallucinogens In The Treatment Of Mental Health Disorders, Brianna Gagen

Honors College Theses

The percent of people with mental health disorders in the United States have skyrocketed over the past decade. With stigma surrounding the discussion of mental health and the symptoms associated with it, often those that are suffering do not receive sufficient treatment, as they might with a physical illness. The current, common treatment options for common psychological disorders, like depression, anxiety, and post-traumatic stress disorder, are sometimes not effective in patients, due to resistance or poor response outcomes. Consequently, in order to research alternative therapeutic approaches for mental health disorders, scientists are researching the effects of several hallucinogenic drugs in …

Greater Sage-Grouse Brood Responses To Livestock Grazing In Sagebrush Rangelands, Hailey Peatross Wayment

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution and abundance of the greater sage-grouse (Centrocercus urophasianus; sage-grouse) have declined in the last 60 years. Range contractions and population declines have been attributed to loss and fragmentation of their sagebrush (Artemisia spp.) habitats. Grazing by livestock remains the predominant anthropogenic land-use across sagebrush ecosystems in North America, occurring on 87% of remaining sage-grouse habitat. Most of the peer-reviewed literature reports the potential for negative impacts of sagebrush reduction treatments, to increase livestock forage, on sage-grouse habitat. However, few studies have linked livestock grazing at the landscape level to vital rates (e.g., nest initiation rates, …

The Effect Of Attachment Design And Aligner Material On The Efficiency Of Maxillary Canine Distalization In Premolar Extraction Cases, Najem Anbari

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: Clear Aligner Therapy (CAT) is regarded as a popular esthetic alternative to conventional orthodontic treatment with fixed labial appliances. The mechanism of action, force delivery and limitation of this treatment modality remain largely unknown despite its popularity, the high demand and the relatively long evolutionary track of clear aligners. There are only few studies that addressed the elements that influence the efficiency of clear aligners, namely, the attachment design and aligner materials. It is widely believed that clear aligners are not suitable for extraction cases due to their lack of control over the root movement.

Objectives: This in vitro …

Describing Bacterial Mutagenic Hotspots And Signatures Along With The Factors That Drive Them, Carmen Vallin

UNLV Theses, Dissertations, Professional Papers, and Capstones

In my dissertation work, I investigated bacterial mutagenesis. I asked: where do mutations occur in the bacterial genome? What types of mutations occur? What factors promote or prevent mutations? And lastly, how do the answers to these questions change depending on the bacterial life cycle (When)? I used Bacillus subtilis, a Gram-positive bacterium belonging to the phylum Firmicutes, and Escherichia coli, a Gram-negative bacterium belonging to the phylum Proteobacteria, to answer these questions. B. subtilis and E. coli are model systems that have been used to gain insights into fundamental processes of mutations and evolution for nearly ~8 decades. Here, …

Comparative Analysis Of Rna Tran-Scriptomes In Ptsd Patients, Tyler Forrest Chan

Honors Capstone Projects and Theses

No abstract provided.

Mycobacteriosis Of Striped Bass (Morone Saxatilis) In Virginia Tributaries Of The Chesapeake Bay, Joshua S. Mcgilly

Biological Sciences Theses & Dissertations

Mycobacteriosis was first documented in Chesapeake Bay striped bass (Morone saxatilis) in 1997 after fish exhibited emaciation and skin lesions. Since it was first identified, studies of mycobacteriosis in the mainstem of the Chesapeake Bay (2003-2007) and the Rappahannock River (2005-2012) have shown high disease prevalence and disease-associated mortality. Until this study, no current prevalence data existed from the Rappahannock River, and no published prevalence data existed for the James River, leaving a gap in our understanding of this disease in major Chesapeake Bay tributaries. We began gathering mycobacteriosis prevalence data from an existing survey collecting striped bass …

Simulating Polistes Dominulus Nest-Building Heuristics With Deterministic And Markovian Properties, Benjamin Pottinger

Undergraduate Honors Theses

European Paper Wasps (Polistes dominula) are social insects that build round, symmetrical nests. Current models indicate that these wasps develop colonies by following simple heuristics based on nest stimuli. Computer simulations can model wasp behavior to imitate natural nest building. This research investigated various building heuristics through a novel Markov-based simulation. The simulation used a hexagonal grid to build cells based on the building rule supplied to the agent. Nest data was compared with natural data and through visual inspection. Larger nests were found to be less compact for the rules simulated.

Effect Of Soil Conditions On Invasive Purple Loosestrife Compared To Native Species, Madeline Ruth Baum

Theses, Dissertations and Culminating Projects

Purple loosestrife (Lythrum salicaria) is an invasive plant that has degraded many wetland habitats since its initial introduction to the United States in the early 19th century. To aid in managing purple loosestrife, it is important to study how purple loosestrife grows under variable environmental conditions compared to common native species, which can help managers understand which habitats are most at-risk of invasion. High or low salinity and pH are often barriers to plant growth, and the stress caused by these environmental conditions can cause plants to deplete their starch reserves. If native species are more negatively affected by stressful …

Keeping Your Cool: Thermoregulatory Performance And Plasticity In Desert Cricetid Rodents, Richard W. Ramirez, Eric A. Riddell, Steven R. Beissinger, Blair O. Wolf

Biology ETDs

Small mammals in hot deserts often avoid heat via nocturnality and fossoriality and are thought to have a limited capacity to dissipate heat using evaporative cooling. Research to date has focused on thermoregulatory responses to air temperatures (T_a) below body temperature (T_b). Consequently, the thermoregulatory performance of small mammals exposed to high air temperatures is poorly understood, particularly responses across geographic and seasonal scales. We quantified the seasonal thermoregulatory performance of four cricetid rodents (Neotoma albigula, N. lepida, Peromyscus eremicus, P. crinitus) exposed to high T_a, at four sites …

Metabolic Signatures Of Kin Recognition In The Model Angiosperm Arabidopsis Thaliana, Thiara Siqueira Bento

Theses and Dissertations

Many organisms have evolved to identify and respond to differences in genetic relatedness between conspecifics, allowing them to select between competitive and facilitative strategies to improve fitness. Due to their sessile nature, plants frequently draw from the same pool of nutrients, and the ability to limit competition between closely related conspecifics would be advantageous. Over the last 3 decades, significant evidence has accumulated in multiple species that such ‘kin recognition’ (KR) is indeed commonplace in plants. I propose that if KR has evolved, at least in part, as a plant-plant interaction to regulate nutrient uptake, then nutrients should modulate the …

Nanotechnology-Based Approaches To Mitigate Environmental Pollutants -- Induced Neurological Disorders, Jyoti Ahlawat

Open Access Theses & Dissertations

Neurodegenerative diseases such as Parkinson's disease (PD), Alzheimerâ??s Disease (AD) and Huntingtonâ??s Disease (HD) have no cure despite intensive research efforts geared towards therapeutics development. In the USA, patients with PD and AD alone cost the nation ~ $200 billion annually in patient care and lost productivity. Therefore, there remains an urgent and unmet need to develop novel drugs and drug carriers with the potential to slow down, halt and ideally reverse the course of neurodegenerative disorders. The dissertation focuses on developing approaches towards targeting PD using multifactorial mechanisms including the targeting of protein aggregation and oxidative stress. This is …