Biochemistry, Biophysics, and Structural Biology Commons^™

Detection And Evaluation Of Hazardous Mercury Contamination In Various Biological Samples, Krish Italiya

Biochemistry and Molecular Biology

Mercury is a toxic environmental pollutant that threatens ecosystems and human health. This study investigates mercury contamination in Lactuca sativa (lettuce) and selected fish species, including tuna and salmon, focusing on plant responses and the limitations of X-ray fluorescence (XRF) analysis. In a controlled experiment, lettuce plants were exposed to mercury to evaluate uptake and toxicity, and XRF spectroscopy was used for quick, non-destructive elemental analysis. Results confirmed mercury accumulation in lettuce, along with visible stress symptoms such as leaf yellowing, purple pigmentation, and tissue damage. Mercury was not detected in tuna and salmon samples, likely due to concentrations below …

Elucidating The Role Of The Rnf20 Histone Modifier In Pancreatic Beta Cells, Tanya Hans Pierre

ETDs from 2020-2029

Diabetes is defined as a loss of functional beta cell mass. It is classically categorized into Type 1 Diabetes (T1D), immune-mediated beta cell destruction and Type 2 Diabetes, which is characterized by whole body insulin resistance alongside beta cell dysregulation. The incidence of diabetes worldwide has risen annually. Despite the presence of therapeutic interventions, diabetes’ heterogeneity can prompt ineffective glycemic control and the development of diabetes-associated comorbidities. For that reason, new approaches to glycemic control for individuals with diabetes are required. One approach to restore glucose homeostasis is beta cell replacement therapy, in which stem cells are programmed into beta-like …

Hydroxamate Formation In The Lipopeptide Containing Siderophore Taiwachelin, Aaron J. Gringer, Kernen P. Agwaza, Isabel Da Fonseca, Pablo Sobrado

Chemistry Faculty Research & Creative Works

Cupriavidus taiwanensis is a nitrogen-fixing bacterium found in root nodules of the invasive tropical weed Mimosa pudica . C. taiwanensis has been shown to grow in environments contaminated with heavy metals such as Pb, Cu, and Cd. Taiwachelin, a recently identified siderophore produced by C. taiwanensis , is an iron chelator that contains a hydroxamate functional group for metal binding. In its biosynthesis, a flavin-dependent N-monooxygenase (NMO) was predicted to hydroxylate l -ornithine, leading to formation of the metal binding hydroxamate moiety. Here, we report the cloning, expression, and biochemical characterization of this enzyme, herein referred to as CtNMO. CtNMO …

Developing A High-Resolution Off-Axis Common-Mode Digital Holographic Microscope, Lucy Cook

University Honors Theses

Off-axis digital holographic microscopy (DHM) is a powerful tool for 3D, non-invasive live-cell tracking without moving parts. However, traditional setups face an inherent dilemma: split-path interferometers offer high spatial resolution but poor temporal stability, while more stable common-mode configurations are historically limited to lower numerical aperture (NA) regimes. This thesis bridges that gap by scaling a common-mode DHM architecture into a high-resolution benchtop instrument featuring NA = 0.65 objectives, paired with a high-power 520 nm laser source to combat transmission losses and sustain imaging frame rates across an expanded optical footprint. We map the multi-variable design space required to satisfy …

Structure Of Ergosteryl-Aspartate Synthase Reveals How An Entrapped Trna Is Used Like A Prosthetic Swinging Arm In The Synthesis Of Aminoacylated Sterols, Hanako Murayama, Nathaniel Yakobov, Nassira Mahmoudi, Sasha Legrosdidier, Nicolas Fournier, Solène Zuttion, Kanata Matsumoto, Michihiro Nishimura, Jingwei Ji, Bruno Senger, Laurence Huck, Howard Gamper, Yoshiaki Kise, Ralph Kleiner, Mathieu Frechin, Ya-Ming Hou, Hubert Becker, Yuzuru Itoh, Frédéric Fischer, Osamu Nureki

Department of Biochemistry and Molecular Biology Faculty Papers

Ergosteryl-3β-O-L-aspartate synthase (ErdS) catalyzes tRNA-dependent aspartylation of ergosterol, a lipid essential for fungal cell membrane integrity. However, the functional significance of ergosteryl-aspartate and the molecular mechanisms underlying its synthesis remain unclear. Here, we show that ErdS localization is highly dynamic and that Erg-Asp is required for proper hyphal growth, sporulation, and spore germination, and likely influences stress tolerance. The cryo-electron microscopy structure of ErdS revealed an unprecedented sterol-binding pocket. In addition, the structures in complex with a non-hydrolyzable Asp-N-tRNAAsp show a tRNA-guided intramolecular aminoacyl transfer mechanism between two functional domains of the enzyme. The CCA end of tRNAAsp undergoes a …

High-Throughput Robotic Ethanol Inhibition Assays For Engineered Thermophilic Biofuel Strains, Kevin He, Daniel Olson, Marybeth Maloney, Anthony Lanahan

Wetterhahn Science Symposium Posters

Ethanol stress assays are commonly used to evaluate microbial tolerance, metabolic adaptation, and fermentation performance. However, manual liquid handling introduces variability across replicate wells and small-volume pipetting steps, limiting reproducibility and throughput. This study developed an automated OT-2 robotic workflow to generate replicated ethanol concentration gradients for high-throughput inhibition assays in engineered thermophilic biofuel strains. Kinetic plate-reader measurements were used to quantify ethanol-dependent growth responses under anaerobic fermentation conditions. The reasearch question is: How do engineered thermophilic biofuel strains differ in ethanol-dependent growth inhibition under anaerobic fermentation conditions, and can automated robotic assays improve the reproducibility of these measurements? Can …

Somatic Prosthetics For Planetary Resonance, Disha Dharesh Kumar R

Masters Theses

This thesis investigates how industrial design can transcend extractive technological paradigms in favor of relational interfaces that foster planetary attunement. Framing the climate crisis as a 'crisis of imagination', the research challenges the Western bifurcation of nature and culture by drawing on Indic cosmologies- which recognize stones, plants, and ecosystems as conscious at different levels and participants in a shared cosmic field. By synthesizing research in Biosemiotics, Quantum Information Pansycishm, and Neuroscience, the project redefines intelligence as a distributed, more-than-human phenomenon.

The research materializes as a speculative design artifact: a device that functions as a somatic prosthetic for planetary resonance. …

Crystal Structure Of Mouse Dxo In Complex With The Udp-N-Acetylglucosamine Cap And Molecular Mechanism For The Decapping Reactions, Najeeb Ullah, Selom K. Doamekpor, Liang Tong

Department of Biochemistry and Molecular Biology Faculty Papers

Noncanonical metabolite 5' caps have recently been identified on RNAs, and the DXO/Rai1 family of enzymes can remove these caps in eukaryotes. While the binding modes of NAD, FAD and dephospho-CoA (dpCoA) caps in the active site of mouse DXO have been determined, how DXO recognizes the UDP-glucose (UDP-Glc) and UDP-N-acetylglucosamine (UDP-GlcNAc) caps is not known. In addition, the molecular mechanism by which DXO catalyzes the decapping reactions is still poorly understood, especially the location of the water/hydroxide that attacks the scissile phosphate to initiate the decapping. Here we report the crystal structure of mouse DXO in complex with UDP-GlcNAc …

Combating Β-Lactamase Resistance: From Inhibitor Design To Substrate Evolution, Lian M.C. Jacobs

USF Tampa Graduate Theses and Dissertations

β-lactamase production by bacteria is a major mechanism of antibiotic resistance. These enzymes hydrolyze β-lactam antibiotics, preventing them from binding to and inhibiting PBPs. Although new β-lactam scaffolds and inhibitors are continually introduced into the clinic, resistance often emerges within a few years. Therefore, the development of cross-class inhibitors with novel scaffolds is critical to mitigate this resistance. In parallel, a deeper understanding of the structural and mechanistic basis of β-lactamase resistance is essential. Together, these approaches provide an effective strategy for combating antibiotic resistance.

The first project addressed the need of effective cross-class β-lactamase inhibitors capable of targeting SBL …

The Heterogeneous Response Of Astrocytes In Different Brain Regions Under Metabolic Stress, Pawan Kumar Thapaliya

USF Tampa Graduate Theses and Dissertations

Astrocytes play a central role in maintaining ionic homeostasis, neurotransmitter clearance, and brain en-ergy metabolism. Their excitability, reflected in activity-evoked intracellular sodium (Na+, [Na+]i) and calcium (Ca2+,[Ca+]i) dynamics, is increasingly recognized as a critical determinant of neuronal function and vulnerability, particularly under metabolic stress. Despite their importance, the mechanisms underlying astrocytic ionic signaling and its regional heterogeneity remain incompletely understood. In this thesis, I developed detailed computational and biophysical models to investigate astrocytic Na+ and Ca2+ dynamics, their bioenergetic consequences, and the roles of key ion transporters under physiological and metabolically stressed conditions, validating the models against experi- mental data. …

In Vitro Reversal Of Abc Transporter Mediated Multidrug Resistance In Human Ovarian And Non-Small Cell Lung Cancer Models, Alison K. Kellom, Pia D. Vogel

Biological Sciences Theses and Dissertations

One of the major causes of treatment failure in aggressive cancers is multidrug resistance (MDR), which is linked to the overexpression of membrane efflux proteins that export chemotherapeutics from cancer cells. This mechanism prevents chemotherapeutic drugs from reaching cytotoxic concentrations intracellularly, allowing the cancer to survive. Two primary mediators of this mechanism are P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). P-gp and BCRP are transmembrane ATP-binding cassette (ABC) transporters that are frequently overexpressed in MDR cancers. They utilize the binding and hydrolysis of ATP to transport a diverse range of amphipathic molecules of varying size (Schinkel and Jonker, 2003), …

Microtubules In Breast Cancer: Exploring The Α/Β-Tubulin Toggle Switch And Its Implications In Human Breast Cancer, Annemarie Ianos

Student Theses and Dissertations

Microtubules, composed of a/b-tubulin heterodimers, play a central role in breast cancer tumor growth by polymerizing, leading to metastasis and depolymerizing, contributing to proliferation. Human enzymes protein kinase Ca (PKC-a) and cyclin-dependent kinase 1 (Cdk-1) mediate phosphorylation at sites a:Ser165 and b:Ser172, respectively, influencing the growth of microtubules. It is possible that alternating phosphorylation at these sites contribute to an a/b-tubulin “toggle switch” that mediates microtubule instability and tumor growth.

The project investigates the influence of the toggle switch model on microtubule stability by determining the impact of mutants (a:S165D, a:S165N, a:S165S_P, b:S172S_P and a:S165S_P/b:S172S …

Computational Design Of Peptides And Proteins Through Machine Learning Approaches, Emily J. Hendrix

Chemistry and Chemical Biology ETDs

Advancements in machine learning have emerged as a pivotal tool in computational biochemistry, offering new advancements to address challenges in protein structure and function. However, current machine-learning approaches offer limited insight in understanding protein dynamics. The purpose of this work is to combine traditional physics-based computational tools, such as molecular dynamics and coarse-grained simulations, with recently developed AI-driven computational tools to bridge gaps and advance the understanding of proteins in both structural and dynamic aspects. I investigated several approaches such as (i) traditional physics-based methods to study protein conformation and ensembles; (ii) identifying a peptide inhibitor for the PICK1 PDZ …

Virus-Like Particle Peptoid Conjugate As A Triple-Negative Breast Cancer Targeting Delivery System, Ricky Zhu

Chemistry Theses

Triple-negative breast cancer (TNBC), an aggressive form of breast cancer, characterized by its lack of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptors (HER2) poses a therapeutic challenge as common treatment options are rendered ineffective. Here is a strategy to develop a drug delivery system utilizing poly-glycinated LC129 8, a TNBC targeting peptoid, covalently attached to HK97 virus-like particles (VLP) containing a C-terminal LPETG sequence via a sortase mediated reaction. Using the properties of the cage-like structure of VLPs and the TNBC specificity of the LC129-8, high doses of chemotherapy can be efficiently loaded into the …

Skin Of Frog And Scale Of Dragon: Nutritional Cues, Life Cycle Kinetics, And Secretome Dynamics In Batrachochytrium Dendrobatidis, Naomi C. Okada

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nearly 50% of amphibian species are at risk of extinction, making them the most threatened group of vertebrates on the planet. A major driver of these declines is the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the fatal skin disease chytridiomycosis. Since its discovery in the late 1990s, Bd has been directly implicated in the extinction of 90 species of amphibians and the declines of hundreds more. Despite this devastating ecological impact, relatively little is known about its basic cellular biology.

Bd has a multi-stage asexual life cycle consisting of a motile and infectious zoospore, which encysts (into a …

The Effects Of Cinnamaldehyde On Tetrahymena Thermophila, Sydney Kurland

Publications and Research

In addition to their common use as spices in cooking and baking, cinnamon plants, Cinnamomum zeylanicum and Cinnamomum cassia for example, have long been used in herbal remedies worldwide. Cinnamon contains many vital oils and active compounds including cinnamaldehyde (CMD). Numerous studies looking at potential therapeutic effects of cinnamon have demonstrated its antioxidant, anti-inflammatory, and antimicrobial properties (1, 2, 3).   Therefore, it is important to continue studying the efficacy, benefits, and mechanisms of action of cinnamon and CMD to have a complete understanding of its full potential. Tetrahymena thermophila is a ciliated protozoan commonly used as a model organism to …

Developing Antibodies Against Galectin-3 And Galectin-9 To Target Endometriosis, Ashleigh Burger, Noah Farnsworth, Jared J. Reisnouer, Cheyenne Vue

2026 Symposium

Endometriosis is a disease characterized by pelvic pain and the formation of endometrial-like tissue on the outside of the uterine lining. This condition affects nearly 10% of women across the globe and confirming whether someone has endometriosis requires visualization in surgery. While the specific causes of this disease remain unclear, the over-expression of the Galectins 3 and 9 in ectopic endometrial tissues suggests a role in the development and maintenance of the condition. Monoclonal antibodies (mAbs) are highly specific proteins with potential as diagnostic or treatment tools. The goal of this study is to generate antibodies against Gal3 and Gal9. …

The Influence Of Prosthetic Obturators On Quality Of Life In Individuals With Maxillectomy Defects, Minseok Kim

Oral Health

Abstract

Introduction: In recent years, there has been a growing focus on understanding the impact of oral cancer on patients' quality of life. Prosthetic rehabilitation techniques, such as maxillary obturators, often in conjunction with reconstructive surgery, have emerged as interventions to address the challenges posed by post-maxillectomy abnormalities.

Objective: This study aims to systematically review and evaluate the effectiveness of maxillofacial prosthetic rehabilitation using obturators in enhancing the quality of life of patients following maxillectomy.

Methodology: Systematic review of identified literature spanning the timeframe from 2000 to 2020 was used. The comprehensive search encompassed widely recognized databases including PubMed, …

Bax Activation Through The N-Terminal Bh3-Like Domains Of Vdac1 And Vdac2, Autumn A. Peters

Honors Theses

Voltage-dependent anion channels (VDACs) are central to mitochondrial function by mediating metabolite diffusion across the mitochondrial outer membrane (MOM). Two isoforms­­­­­­­­­­­,­­­­­­­­­­­­­­­­­­­­­­­­­­­­ VDACs 1 and 2, are also implicated in apoptosis based on interactions with Bcl-2 family proteins that control this process, including Bax and Bcl-xL. Activation of the pro-apoptotic protein Bax by interaction with ‘BH3-only’ proteins, such as Bim or Bid, induces MOM permeabilization to signal apoptosis, yet accumulating evidence indicates VDACs 1 and 2 may also affect Bax. We discovered that the VDAC N-terminal domains contain high sequence similarity to the conserved BH3 domains within Bcl-2 family members that …

Windows Of Developmental Susceptibility To Tetrahydrocannabivarin (Thcv) Reveal Stage-Dependent Morphological And Biological Effects, Mirielle Clayton

Honors Theses

Tetrahydrocannabivarin (THCV), a minor cannabinoid found in Cannabis sativa, is gaining attention for its potential therapeutic applications, yet its effects on early development remain poorly understood. This study investigated how the timing of THCV exposure influences morphological, behavioral, and bioaccumulation outcomes in zebrafish (Danio rerio) embryos. Embryos were exposed to 2 μM THCV during discrete developmental windows (6–30, 30–54, 54–78, 78–102) and continuous 6–102 hours post-fertilization (hpf), designed to model early stages of human gestation. Behavioral analysis using a larval photomotor response assay revealed significant reductions in locomotor activity during dark phases, with the strongest hypoactivity observed …