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Winners And Losers In Dryland Reforestation: Species Survival, Growth, And Recruitment Along A 33-Year Planting Chronosequence, Clifton Albrecht, Zarek Contreras, Kimberly Wahl-Villarreal, Mitch Sternberg, Bradley O. Christoffersen

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Reforestation in the Lower Rio Grande Valley (LRGV) of Texas began in the 1960s and to date over 6,475 ha of land has been reforested. However, there has been minimal assessment to understand differential species success, compositional trends, and the aboveground C sequestration potential of these developing forests. We coupled quantitative planting information of >50 native woody tree and shrub species with surveys of 5,223 stems of 4,606 individuals in a chronosequence of restored forests ranging in age from 1 to 33 years to estimate species-specific mortality rates, biomass accumulation and recruitment, as well as compositional trends in the herbaceous …

Elevated Levels Of External Cysteine Inhibit Nitrogen Fixation By The Methanogenic Archaeon Methanosarcina Acetivorans, Regan Massey

Biological Sciences Undergraduate Honors Theses

Methanogens are nitrogen fixing and methane producing archaea that play a key role in the cycling of carbon and nitrogen on earth. The global carbon and nitrogen cycle is vital to all life which makes the methanogen a primary organism of study. Methanogens are the only archaea capable of fixing nitrogen, and in order to do so, methanogens use a vital enzyme called the nitrogenase which fixes dinitrogen (N2) to ammonia (NH3). Expanding our understanding on metabolic processes of methanogens allows us to understand their environmental impact and advance their use in biotechnological applications. Methanosarcina acetivorans is the model used …

Effects Of A Leucine Supplementation On Mitochondrial Markers In Pre-Cachectic Female Mice, Breanna Williams

Biological Sciences Undergraduate Honors Theses

Cancer cachexia is a wasting syndrome characterized by extreme weight and skeletal muscle loss that results in death in many tumor bearing individuals. Because skeletal muscle requires a high amount of energy to function, skeletal muscle fiber cells need healthy mitochondria to function. When skeletal muscle loss atrophy occurs, the mitochondrial network is degraded. Different treatments for this muscle atrophy are being studied, one of which is a leucine supplementation since leucine has been found to stimulate skeletal muscle growth in other studies. However, current data suggests that a leucine supplementation in cachexic individuals exacerbates this atrophy. PURPOSE: This study …

Spike Protein Structural Dynamics Of Sars-Cov-2 Coronaviruses Studied Using Molecular Dynamics, William Strickland

Biological Sciences Undergraduate Honors Theses

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has overwhelmingly impacted the global population, accounting for millions of confirmed infections and deaths over the last year. The virus’s influence on the health and safety of individuals, the economy, and daily life has been disruptive and devastating. While SARS-CoV-2 and SARS-CoV-1, two closely related members of the SARS coronaviruses, have shown the ability to cross the species barrier and infect humans, SARS-CoV-2 has predominantly been the virus responsible for the number of infections presently known. SARS-CoV-2 has also proven to be volatile, as many variants have …

The Effects Of Deletion Of The Cytoplasmic Domain Of Robo3 On Drosophila, Jessie Agcaoili

Biological Sciences Undergraduate Honors Theses

My research project examines how the deletion of the cytoplasmic domain affects the function of Robo3. If Robo3 is signaling repulsion in response to SLIT this activity should require the cytoplasmic domain. I investigated the functional importance of Robo3 by deleting the cytoplasmic domain of Robo3 using a CRISPR-based technique. This modified gene was then injected into Drosophila embryos where it replaced the normal copy of the gene. Embryos expressing the modified version of robo3 in place of normal robo3 were dissected and examined.

Exploring Nitrogen Fixation In Methanosarcina Acetivorans, Rylee Cook

Biological Sciences Undergraduate Honors Theses

As of 2016, the genomes of over sixty species of methanogenic archaea have been sequenced.4 Research on the genomes of methanogens such as M. acetivorans led to the characterization of numerous genes with unknown functions. Genes similar to those of nitrogenase have been shown to possess functions unrelated to nitrogen fixation, such as F430 biosynthesis genes. 5,6,7 My research focused on the uncharacterized gene clusters ma2032-33 and ma1631-33 (Figure 1). These genes have conserved nitrogenase domains: ma2032 has fused nifH and nifD domains, while ma2033 has a nifD domain. The ma1631-33 gene cluster contains two nitrogenase homologs and one iron …

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 …

The Role Of Angiocrine Factors In The Progression Of Salivary Disease, Owen Zon

Biological Sciences

In our blood vessels, cells called endothelial cells line the inside of veins and arteries. Due to the discovery that endothelial cells actually organogenesis during embryogenesis, our interest in these cells has increased to a new understanding of their functions in tissue repair and regeneration. These cells are no longer only considered passive modes of transport for bodily fluids and nutrients, but, with new research in the fibrosis of liver cells, are also considered to be key players in the repair of damaged organs and tissue. These cells release signals known as angiocrine factors that act in damaged areas of …

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 …

Removal Of Arsenic (Iii) And Arsenic (V) From Aqueous Solution Via Common Sunflower Helianthus Annuus By Phytoremediation, Irving A. Vazquez Hurtado

Theses and Dissertations

Phytoremediation provides a cost-effective, non-invasive technique to remove contaminants from the soil and groundwater. Sunflowers are fast growing and have a showed effective at removing various pollutants from soil, including lead and other heavy metals. Health issues related to arsenic are mainly attributed to exposure of arsenite, whereas arsenate is much less toxic. The common sunflower Helianthus annuus was the species used to remove both arsenic (III) and As(V) ions from hydroponics solutions. In the present study sunflower seeds were germinated for a week, placed under the sun for a day and subsequently placed in a nutrient solution to aid …

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 …

Using Macroinvertebrates To Assess The Effects Of Nutrient Input Between The Nolichucky And Pigeon Rivers, Anna Grizzard

Electronic Theses and Dissertations

Previous work found significant differences in growth rates of native mussels at locations downstream from the regulated Walter’s Dam and the out-of-service, free-flowing Davy Crockett Dam. The purpose of this study is to investigate differences within the macroinvertebrate communities related to factors driving the differences in mussel growth between rivers. Macroinvertebrate samples were collected following the Tennessee Department of Environment and Conservation protocol for SQKICK collection and analyzed using the Tennessee Macroinvertebrate Index (TMI). There were no significant differences in TMI scores between the downstream sites of the rivers, but there were significant increases in chlorophyll_a, dissolved oxygen, …

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 …

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 …

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 …

Effects Of 2,4-Di-Tert-Butylphenol On Osteogenic And Myogenic Differentiation Of Human Induced Pluripotent Stem Cells, Thanh-Bình Dương

All Theses

Synthetic phenolic antioxidants (SPAs) are a class of compounds used to increase the durability of polymers as well as to increase the shelf-life of food, cosmetics, and other personal care items. Of these SPAs is 2,4-di-tert-butylphenol (2,4-DBP). 2,4-DBP is primarily used in polyethylene crosspolymer pipes, which are now used as a replacement for the traditional copper pipes for household water distribution. However, 2,4-DBP has been found to leach from these pipes into the water, enabling a mode of exposure to humans. 2,4-DBP has been detected in human urine, serum, but more importantly, maternal serum, placenta, and cord blood. …

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 …

Standardization Of A Protocol To Propagate Gateway Vectors, Kayla Suisse

Undergraduate Honors Capstone Projects

Cloning is an important technique in functional genomics, particularly genetics and molecular biology. Cloned genes can be used to facilitate protein expression; this is an essential step in understanding gene function. In traditional cloning, the gene of interest is amplified and tagged with a restriction enzyme sequence and ligated to the digested open vector. However, the GATEWAY™ Cloning Technology provides a speedy and more efficient route to insert the gene of interest in the desired vector, known as Destination vectors or Expression vectors, using site-specific recombination sites and recombinase enzymes.¹ Once DNA segments from the gene of interest are …

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 …

Time Course Investigation Of The Dermal Leukocyte Response To Lipoteichoic Acid In Chickens, Ian Gilbert

Animal Science Undergraduate Honors Theses

Lipoteichoic acid (LTA) is component of the cell wall of Gram-positive bacteria that stimulates inflammation during bacterial infection. However, few studies have investigated the in vivo immune response to LTA, and none of the in vivo studies done have been performed in birds. For this project, the pulp (a skin-derivative) of growing feathers (GFs) of chickens were used as a test site to investigate the in vivo effects of intradermally injected LTA. In Study 1, the pulp of 12 GFs of 11-week-old Light-brown Leghorn (LBL) males were injected with 10 μL of differing concentrations of LTA (0.1, 1.0, 10, 100 …

Evolution Of Floral Microbes And The Resulting Effects On Pollinator Preference, Hailey Hatch

Undergraduate Honors Capstone Projects

Floral microbes are an overlooked aspect of the extended floral phenotype. Through altering floral nectar chemistry, they can mediate interactions between flowers, pollinators, and other floral microbes, with significant implications for plant and pollinator health. Interactions between floral microbes and pollinators are critically important to understand, as pollinators provide important ecosystem services in both natural and agriculture systems. Here, I explored how floral nectar traits affected both evolution and competition within the floral yeast Metschnikowia reukaufii, the floral bacterium Bacillus subtilis, and other microbes isolated from Brassica rapa nectar, an important plant model system and oilseed crop. To …

Effect Of Basal Diet And Black Raspberry Supplementation On Gene Biomarkers Of "Leaky Gut" In A Mouse Model Of Colitis-Associated Colorectal Cancer, Eliza Catherine Stewart

Undergraduate Honors Capstone Projects

Colorectal cancer is currently the second leading cause of cancer death in the world. The risk of developing colorectal cancer increases significantly in individuals who suffer from colitis, which is inflammation of the colon lining, seen in Irritable Bowel Disease. The term “leaky gut” is often used to describe increased intestinal permeability and is closely related to colitis. Leaky gut is associated with dysbiosis of the gut microbiota, which can occur through diet. This dysbiosis leads to prolonged inflammation and affects genes that encode for proteins involved in the tight junctions between cells. Compromised intestinal integrity allows for translocation of …

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 …