Life Sciences Commons^™

Modeling Nonequilibrium Community Dynamics Of Bivalves In The Indian River Lagoon, Jada Lee Brown

Electronic Theses and Dissertations 2020 - Present

Benthic infaunal communities are widely-used indicators for assessing estuarine health, especially in systems that experience frequent disturbances and hydrological fluctuations. However, using benthic infauna to predict ecosystem responses to future disturbances remains a challenge. The Indian River Lagoon (IRL), spanning 40% of Florida's east coast, is a prime example of a complex estuary that has experienced decades of hydrological alterations leading to reduced water quality, sediment composition, and biodiversity. To assess benthic bivalve community dynamics in response to disturbances, an emerging Empirical Dynamic Modeling (EDM) approach was applied to a large test dataset comprising 17 years of benthic bivalve abundances …

From Anaerobic Digesters To The Human Gut: Ecological Responses Of Microbiomes To Environmental And Biological Perturbations, Maliea Annholden Nipko

Theses and Dissertations

Microbial communities regulate essential ecological and metabolic processes across both engineered and host-associated ecosystems. Although these systems differ substantially in composition and function, they are governed by common ecological principles including community succession, resilience, species interactions, and responses to environmental and biological perturbations. This dissertation investigates how perturbations influence microbiome structure, function, and stability through three complementary studies spanning anaerobic digestion and the human gut microbiome. First, the effects of an extremophilic biological pretreatment using Caldicellulosiruptor bescii were evaluated in industrial-scale anaerobic digesters treating dairy manure. High- temperature pretreatment substantially altered microbial community composition, with bacterial populations remaining metabolically active …

Investigating Tumor-Stromal Interactions That Drive Breast Cancer Angiogenesis And Metastasis, Alessandra Dimauro

Arts & Sciences Graduate Student Theses and Dissertations

Metastatic breast cancer remains one of the most difficult cancers to treat, with a five-year survival rate that drops from 99% for localized disease to just 33% once distant metastases are present. This disparity reflects a fundamental gap in our understanding of how breast tumors spread and highlights the urgent need to improve our understanding of breast cancer metastasis to aid in development of novel therapeutics. Emerging evidence establishes that metastasis requires interactions between tumor cells and non-tumor stromal cells within the tumor microenvironment. The first aim of this dissertation investigates the role of Discoidin Domain Receptor 2 (DDR2), a …

Ionophore-Based Plga Nanosensor For Selective Ion Detection And Imaging, Zhiyu Tang

Electronic Theses and Dissertations 2020 - Present

Accurate detection of electrolyte ions is essential for biological research, disease diagnosis, and the investigation of cellular function. In this study, we developed ionophore-based PLGA nanosensors for the optical detection of biologically important ions. The nanosensors were prepared by encapsulating ionophores, chromoionophore III, and ion exchangers within PLGA nanoparticles. The resulting nanosensors showed uniform morphology, good colloidal stability, and concentration-dependent optical responses toward Na⁺, K⁺, and Ca²⁺ over the range of 10⁻⁶ to 10⁻¹ M. Reversible fluorescence responses under repeated ion concentration changes confirmed the stability and robustness of the sensors. The nanosensors also demonstrated reliable analytical performance for K⁺ …

Establishing Thermal Bleaching Thresholds For Montastraea Cavernosa On Florida’S Coral Reef, Olivia Faris

Electronic Theses and Dissertations 2020 - Present

Marine heatwaves are increasing in frequency and duration, with widespread bleaching events and mortality impacts observed on Florida’s Coral Reef. However, thermal bleaching thresholds for corals in Southeast Florida are not well established, limiting the ability to forecast or manage response to thermal stress events in the region. This study was designed to establish bleaching thresholds for Montastraea cavernosa, a reef-building stony coral, in Southeast Florida. Ex-situ experiments were conducted where triplicate M. cavernosa fragments of multiple genotypes were exposed to acute thermal stress or held at intermediate temperatures to simulate chronic stress. Thermal performance curves based on photosynthetic …

Using Temporal Genomic Data To Uncover Patterns Of Genetic Diversity And Signatures Of Selection For Management Of A Threatened Minnow Species, Erika A. Dunn

Biology ETDs

The Little Colorado River (LCR) spinedace persists only in three isolated watersheds within the LCR Basin in Arizona. This imperiled minnow faces ongoing pressure from habitat alteration, climatic shifts, and invasive non-native predators. Over the past two decades, managers have translocated spinedace within watersheds to increase abundance and expand habitat occupancy. We sequenced a reference genome and analyzed single nucleotide polymorphisms (SNPs) from 475 individuals over their geographic range. DNA samples were obtained from a previous study in the mid-1990s and compared with samples from 2024 and 2025, allowing us to track genetic diversity, effective population size, population structure, and …

Scale-Dependent Drivers Of Demographic Change For American Pikas (Ochotona Princeps) In Glacier National Park, Montana: Local Habitat Characteristics Vs. Regional Climate Trends, Danielle M. Owens

Biology ETDs

Climate change is shifting thermal environments globally, driving range contractions, upslope movement, and poleward shifts across taxa. However, these changes are not uniform: microclimates, shaped by topography, can amplify or decouple operative temperatures from regional trends. The American pika is an ideal model for studying climate-driven population change given its strong site fidelity and thermal sensitivities. We re-surveyed 173 sites in Glacier National Park, originally surveyed in 2007-2010, using an AIC-based model selection to test competing local and regional hypotheses driving three demographic processes: persistence, colonization, and within-patch density change. Pika occupancy increased over the 15-year period, with a net …

Finding Fish Families: Movement And Demography Of Loach Minnow (Tiaroga Cobitis) Inferred From Gt-Seq-Enabled Kinship Analysis, Patrick C. Baca

Biology ETDs

River fragmentation poses major threats to freshwater biodiversity by reducing connectivity and limiting persistence of imperiled desert fishes. Connectivity in streams is impaired by anthropogenic changes, including road crossings, prompting the installation of engineered fish passage structures at low-water road crossings and raising questions about the dispersal of aquatic species across these structures. This thesis investigates the movement of the threatened Loach Minnow (Tiaroga cobitis) by applying a close-kin mark-recapture (CKMR) framework in a restored stream (including a fish passage) and a stream without rehabilitation efforts. We developed and optimized a GT-seq panel for relatedness analysis and used it to …

Elucidation Of Micro/Nanoplastic Signature Of Human And Murine Lung Tissue Utilizing Pyrolysis-Gas Chromatography/Mass Spectrometry, Aerlin D. Decker

Pharmaceutical Sciences ETDs

Micro-and Nanoplastics (MNPs) are ubiquitous biological pollutants that have been identified throughout a variety of biological samples. MNPs have been detected in several human tissues, such as the brain, kidneys, and liver. Lung tissue remains understudied for MNP accumulation despite the large surface area and clear path for exposure. Using Pyrolysis-Gas Chromatography Mass Spectrometry (Py-GC/MS), human lung tissue was evaluated for 12 different polymers, enabling quantification of total plastic per gram of tissue to be identified. Further analysis was performed with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to investigate heavy metal accumulation in human lung samples and determine whether a …

Mapping And Modeling Threat-Evoked Brain States After Early Life Adversity, Taylor W. Uselman

Biomedical Sciences ETDs

Early life adversity (ELA) increases lifelong neuropsychiatric vulnerability. Yet how ELA reorganizes brain-wide activity and circuit coordination across later experience remains unclear. This dissertation tests the hypothesis that ELA alters adult brain-wide activity and responses to threat through disrupted coordination among neural systems that regulate emotional experience, including prefrontal-limbic and monoaminergic systems. Longitudinal manganese-enhanced MRI of adult mice exposed to standard or fragmented early care, combined with computational processing and statistical modeling, quantified brain states before, during, and long after innate predator threat. These studies established that acute threat evokes large-scale, distributed brain activity that evolves over time. ELA potentiates …

The Evolution Of Regulatory Architectures Underlying Phenotypic Plasticity, Shweta Agarwal

Biology ETDs

Phenotypic plasticity refers to a mechanism where a single genotype results in distinct phenotypes in response to distinct environments, making it a key mechanism for persistence under environmental change. Phenotypic plasticity can arise from two distinct regulatory architectures: epistatically regulated plasticity or environmentally sensitive loci. The evolutionary forces shaping these architectures remain unclear. I use the recombination modifier framework to explore how the regulatory architecture of plasticity evolves across a range of selection regimes, including the rate of environmental change and the costs and benefits of plasticity. I find that the evolution of the regulatory architecture of phenotypic plasticity requires …

Autotrophic And Heterotrophic Contributions To Soil Co2 Fluxes And Variability In A Chihuahuan Desert Grassland, Savannah B. Sanchez

Biology ETDs

Drylands are major drivers of interannual variability in the global terrestrial carbon sink, and their influence is expected to increase as climate change promotes the expansion of hotter and drier regions. Predicting the consequences of these shifts remains challenging because ecosystem models are largely developed for mesic systems, which differ from drylands in water and nutrient availability, decomposition rates, respiration dynamics, and microbial communities. Improving our understanding of carbon cycling in drylands is therefore critical. This research focuses on soil CO₂ efflux, a major pathway of terrestrial carbon release driven by plant root respiration and microbial decomposition. I investigated the …

How To Measure A Carnivore: Understanding The Scaling Of Cranial And Postcranial Elements With Body Mass, Marina Casiano Ruiz

Biology ETDs

Body size is a fundamental predictor of ecological function, life history, and population dynamics in mammals. However, direct measurements of body mass remain unavailable for many rare or extinct species, particularly within the order Carnivora. Allometric relationships between skeletal dimensions and body mass provide a tractable solution; however, previous studies have been limited in their taxonomic scope or trait diversity. Here, we quantify the scaling of 82 cranial and postcranial traits across 97 species from 11 carnivoran families spanning four orders of magnitude in body mass (20g to >500kg). Additionally, we examine the influence of phylogenetic relatedness, dietary specialization, and …

Uv Damage Mapping Reveals Different Impacts Of Xpd Mutations On Global Genomic And Transcription-Coupled Dna Repair, Allyson Hoag

Biomedical Sciences ETDs

Nucleotide Excision Repair (NER) is a fundamental cellular process that removes bulky and helical distorting lesions from the genome through the separate responses of its two subpathways – global genomic (GG-NER) and transcription coupled (TC-NER) DNA repair. The pathways converge with the recruitment of the TFIIH complex, a key step that is mediated by the translocase and helicase activities of  its XPD subunit. Germline mutations in XPD result in the clinical disorders, Xeroderma Pigmentosum (XP) and XP combined with Cockayne Syndrome (XP/CS). The goal of this thesis was to understand if XPD XP and XP/CS mutations differentially impact GG-NER and …

Thermal Sensitivity Of Native And Introduced Crabs: Implications For Reproductive Success, Keria Moritsugu-Vandehey

Dissertations and Theses

Temperature is a major driver of physiological and developmental processes in marine organisms, and continued climate warming is expected to affect reproduction and recruitment in estuarine species. Early life stages are often particularly sensitive to environmental stress, yet relatively little is known about how warming influences embryonic development, hatching success, and larval survival across co-occurring native and introduced crab species.

This study examined the effects of temperature on embryonic development, hatching success, and early larval survival in four estuarine crab species from the Pacific Northwest: the introduced European green crab, Carcinus maenas, and the native shore crabs Hemigrapsus nudus …

Physiological Impacts Of Plastic Ingestion On Sea Turtles, Heather Seaman

Electronic Theses and Dissertations 2020 - Present

Over the years, plastic production has increased to astonishing numbers and is predicted to continue. Over time, environmental plastic will degrade into smaller pieces, which sea turtles can mistake for prey. Chemicals associated with plastics have been identified in tissues of sea turtles, and some are suspected to be endocrine disruptors. Sea turtles are known to ingest plastics, but more information is needed to illuminate the potential physiological impacts plastic chemicals may have on sea turtles. This study compared plastic ingestion and toxicant levels across species and ontogenically, as different species and life stages inhabit different areas which will influence …

Effects Of Variable Light On Sexual Competition In Kelp Species, Jaycee Lanza

Master's Theses

As foundation species, kelps significantly influence the structure and composition of their surrounding habitat by modifying environmental conditions, including light levels, currents, nutrient availability, sedimentation, and seawater chemistry. Light, in particular, is a critical resource that varies greatly within kelp forests, affecting kelp reproductive processes such as gametogenesis, fertilization, and recruitment, which are vital to population persistence. Biological factors, such as density-dependent competition for resources and sexual competition with other kelps, can also affect such processes. To understand how environmental variables influence kelp populations, it is crucial to recognize their combined effects. This study investigated the impacts of light levels …

Using Fecal Diagnostic Tests To Assess The Prevalence Of Fasciola Hepatica In The United States Sheep Population, Brooke A. Delcambre

LSU Master's Theses

Fasciola hepatica, the common liver fluke, is endemic in the Pacific Northwest and Gulf Coast of the United States. To provide updated information on F. hepatica prevalence, as part of the USDA National Animal Health Monitoring System Sheep 2024 study, sheep operations in the top 30 sheep-producing states were identified, and producers were invited to participate. For each operation, feces were collected from at least eight sheep and pooled to form a single composite sample. Two methods were used to identify sheep infected with F. hepatica: fecal sedimentation and indirect sandwich ELISA. At the national level, across 318 operations, 7.1 …

Enhancing Rapid Reef Resilience Through Transplantation Of Thermally Tolerant Corals In OʻAhu, HawaiʻI, Allison M. Klein

Electronic Theses and Dissertations 2020 - Present

Coral reefs are increasingly threatened by marine heatwaves, disease outbreaks, and other anthropogenic stressors, leading to widespread declines in coral cover worldwide. As a result, efforts are increasingly focused on identifying thermally tolerant corals for reef restoration. However, it remains unclear whether thermal tolerance is maintained following transplantation and whether thermally tolerant corals perform differently in novel environments. This dissertation examined thermal tolerance, survivorship, symbiont communities, and growth in two dominant Hawaiian reef-building corals, Montipora capitata and Porites compressa, using a reciprocal transplant experiment between Kāneʻohe Bay and Ulupaʻu, Oʻahu. Initial heat-stress assays showed high thermal tolerance in both …

Hippocampal “Timing Interval Cells” Exhibit Scalable Dynamics For Explicit Timing, Kori-Anne Citrin

Electronic Theses and Dissertations 2020 - Present

The ability to organize experiences in time is fundamental to episodic memory and enables animals to predict and guide future behavior. Hippocampal time cells are thought to provide a neural representation for the temporal component of memory. However, time cells have been observed in working memory tasks where animals were not required to keep track of elapsed time. Therefore, it remains unclear what are the hippocampal patterns of activity during explicit timing. Here, utilizing behavioral perturbations and calcium imaging in dorsal CA1, we identified a previously unknown pyramidal neuron subpopulation that flexibly scales its activity during explicit timing. As head-fixed …

Biomechanical And Talar Cartilage Responses To Running In Individuals With Chronic Ankle Instability, Minsub Oh

Theses and Dissertations

Context: Chronic ankle instability (CAI) has shown altered movement patterns and joint loading, which increase the risk of posttraumatic ankle osteoarthritis. Abnormal vertical ground reaction force (vGRF) during running may contribute to talar cartilage degeneration; however, the acute biomechanical and cartilage responses to running in individuals with CAI remain unclear. Purpose: The purpose of this study was to compare running biomechanics and changes in talar cartilage thickness and T2 relaxation times before and after running between individuals with CAI and healthy controls. Methods: Twenty individuals with CAI and 20 healthy controls completed running biomechanics and magnetic resonance imaging (MRI) sessions. …

Irrigation Water Conservation And Accelerated Composting: An Exploration Of Environmentally Conscious Practices For Ornamental Horticulture, William James Carson Dunford

LSU Master's Theses

Best management practices for ornamental horticulture include proper management of irrigation water resources and substrate components. The first study investigated the effects of wind speed, wind direction, water pressure, and spray stake height on irrigation efficiency in nursery containers. Results indicated that lower spray stake height positions and lower wind speeds significantly improved the irrigation water volume captured within nursery containers by as much as 18% to 39%. Orienting spray stakes against prevailing winds further enhanced water retention, particularly at 0 and 1 inch heights. In contrast, higher stake elevations led to increased irrigation water loss by as much as …

Epigenetic Regulators Mll3 And Mll4 Sustain Hematopoietic Stem Cell Multipotency, Helen Chenwei Wang

Arts & Sciences Graduate Student Theses and Dissertations

Hematopoietic stem cells (HSCs) maintain lifelong blood production by balancing self-renewal and multilineage differentiation. They are sustained by networks of transcription factors and epigenetic regulators that prime lineage-specific programs while simultaneously preventing activation of any one program up until the moment of lineage commitment. Despite extensive study, it remains unclear how these complex transcriptional programs are coordinated and how specific epigenetic regulators are deployed to reinforce specific cell fate decisions. Epigenetic regulators, MLL3 and MLL4, play a central role in pluripotent embryonic stem cell fate transitions, but their functions in multipotent somatic stem cells are less well characterized. MLL3 (also …

Development Of Novel Plasminogen Activators From Fragments Of Streptokinase Enzyme, Vijay G Mr

Theses and Dissertations

Thrombotic disorders such as myocardial infarction, ischemic stroke, pulmonary embolism and deep vein thrombosis remain major causes of mortality and disability worldwide, creating a continuing need for effective, safe and affordable thrombolytic therapy. Streptokinase is one of the most widely used plasminogen activators because of its activity, low cost and broad availability. However, its wider clinical utility is limited by high immunogenicity, allergic reactions, neutralizing antibody formation and poor suitability for repeat administration. This thesis aimed to develop novel streptokinase-derived plasminogen activators by identifying smaller functional fragments that retain thrombolytic activity while potentially reducing immunogenicity.

A literature-guided fragment-based strategy was …

The Effects Of Anti-Gdnf On The Sensory And Autonomic Nervous System In The Heart, Tryphosa Konadu

Honors Theses

Heart disease is the number one leading cause of death; about 1 in every five deaths is due to heart disease. “Heart disease” is a catch-all phrase that encompasses a variety of conditions that affect the heart’s structure and function. Many of these symptoms can be attributed to dysfunction within the parasympathetic, sympathetic, and sensory nervous systems. Neurotrophic factors like GDNF (Glial cell line-derived neurotrophic factor), BDNF (Brain-derived neurotrophic factor), and NGF (Nerve growth factor) promotes neuronal survival, and regeneration of the nerve fibers of the heart, especially sensory and autonomic nerve fibers. Studies have suggested that increased expression of …

Drifting Neurons, Stable Geometry: Population Representations Of Instrumental Behavior In The Dorsomedial Striatum, Arati Sharma

Dartmouth College Ph.D Dissertations

The brain reliably supports learned behaviors over long periods of time despite continual biological changes that alter the activity of individual neurons, and the connections between them. For learned behaviors to persist, the information stored in neural populations must remain accessible even when the activity of individual neurons changes. Understanding how the brain achieves this is a fundamental challenge in neuroscience. The dorsomedial striatum (DMS) is critical for instrumental behavior, encoding information about actions, outcomes, and their relationships. Although extensive work has characterized the role of the DMS during learning and performance, less is known about how task-related information is …

Movement And Distribution Dynamics Of Predatory Fishes In The St. Lucie Estuary, Sarah Fae Leonowicz Torre

Electronic Theses and Dissertations 2020 - Present

Estuaries are productive but highly variable ecosystems that support recreationally and commercially valuable fisheries, as well as species of conservation concern. However, coastal development, habitat loss, altered freshwater inflow, and declining water quality can modify the environmental gradients that structure fish distributions. In the St. Lucie River and southern Indian River Lagoon, located in southeast Florida, managed freshwater discharges, watershed runoff, shoreline modification, and degradation of essential fish habitats (e.g., seagrass, oyster, and mangrove forests) have altered estuarine conditions.

This dissertation evaluates how four estuarine fish species with contrasting life histories respond to environmental variability, hydrologic disturbance, and habitat structure …

Transcriptomic And Genomic Insights Into Nutrient Stress Responses And Subgenome Evolution In Chenopodium, Ashley Kathleen Marcheschi

Theses and Dissertations

Chenopodium is a diverse genus of nutritionally and ecologically important species in the Amaranthaceae family. This thesis investigates two outstanding questions in the genus: how Chenopodium quinoa responds transcriptionally to nutrient deficiency and how Australian Chenopodium species are related through their subgenomic ancestry and evolutionary history. First, we characterized transcriptomic responses of C. quinoa to deficiencies of twelve essential macro- and micronutrients across leaf and root tissues using RNA sequencing. Leaves showed the strongest responses under nitrogen, potassium, magnesium, and zinc deficiency, while roots responded more evenly across conditions. Recurring responses included suppression of photosynthesis, remodeling of translational machinery, reactive …

Nitrogen Management Strategies For Specialty Tea Production In Louisiana: Rate, Source Type, And Nutrient Dynamics, Autumn D. Hilderbrand

LSU Master's Theses

Tea (Camellia sinensis L.) is an emerging specialty crop in Louisiana and the southeastern United States; however, region-specific nitrogen (N) management recommendations remain limited. This research evaluated N fertilizer source, application rate, and nutrient leaching to identify management strategies that improve nitrogen use efficiency (NUE) and environmental sustainability during tea establishment.

Three complementary studies evaluated N source replacement, application rate, and fertilizer source effects on nutrient retention and movement. The first study evaluated the replacement of urea ammonium sulfate (UAS) with blood meal (BM) while maintaining a constant annual N application rate. Fertilizer replacement did not significantly affect leaf …

Engineering Fsh-Cer T Cells To Enhance Response To Epithelial Ovarian Cancer, Nolan J. Beatty

USF Tampa Graduate Theses and Dissertations

Ovarian cancer remains a significant cause of cancer-related mortality, with epithelial ovarian cancer (EOC) being the most common subtype. Despite advances in treatment, the 5-year survival rate for late-stage EOC remains low due to factors such as tumor heterogeneity and an immunosuppressive tumor microenvironment (TME). This study investigates the therapeutic potential of chimeric endocrine receptor (CER) T cells engineered to express follicle stimulating hormone (FSH) in a syngeneic mouse model of EOC expressing follicle stimulating hormone receptor (ID8-FSHR). We compared two different co-stimulatory domains—CD28ζ and 4-1BBζ—in FSH-CER T cells and found that FSH-CD28ζ CER T cells exhibited enhanced cytotoxicity, proliferation, …