Biochemistry, Biophysics, and Structural Biology Commons^™

Chromatin Insulators Homie And Nhomie Can Interact With Distant Copies Either Together Or Separately, With Distinct Outcomes For Enhancer-Promoter Interactions, Miki Fujioka, Wenfan Ke, Paul Schedl, James B. Jaynes

Department of Biochemistry and Molecular Biology Faculty Papers

Chromatin insulators, a.k.a. boundary elements, separate regions of the chromosome with distinct chromatin characteristics, including distinct histone modifications. This activity affects gene expression by allowing chromatin domains to be stably regulated and maintained. Insulators also block enhancer-promoter interactions and, somewhat paradoxically, facilitate other interactions, particularly when they stitch together distant regions of the chromosome by pairing with specific partners. Here we explore how long-range interactions facilitated by insulator pairing are affected by the presence of two potentially competing partners. Our results show that when two partners are present, they can reduce each other's effects on distant gene expression, suggesting that …

Synthesis And Characterization Of Organometallic Polymers And Their Cytotoxicity Towards Human Cancer Cell Lines, Paul Peter Slawek

Electronic Theses and Dissertations

This research aimed to synthesize organometallic polymers from dialkyl (methyl, ethyl, butyl, cyclohexyl, and octyl) and diaryl (phenyl) tin dichlorides and three organic monomers, dipicolinic acid (DPA), chloramphenicol (CH), and isomannide (IS), using interfacial polymerization. Structure-activity relationships were investigated through physicochemical characterization (light-scattering photometry, proton NMR, and IR spectroscopy) and cytotoxicity was evaluated against six human cancer cell lines (AsPC-1, PANC-1, MCF-7, MDA-MB-231, HT-29, PC-3), with cisplatin serving as the reference standard.

Five DPA/tin polymers were synthesized, with IC₅₀ values in the range of 0.60–0.71 μg/mL. Their cytotoxicity was significantly lower than that of cisplatin (0.0023-0.044 μg/mL), suggesting that …

Synthesis And Characterization Of Synergistic Bioactive– Organometallic Condensation Polymers, Francesca Isabel Mosca

Electronic Theses and Dissertations

This research focuses on the synthesis and structural characterization of polymers with anticipated anticancer and antiviral properties by combining metal-containing Lewis acids, organotin dichlorides (R2SnCl2), Group 4 metallocene dichlorides (Cp2TiCl2, Cp2ZrCl2 and Cp2HfCl2), and triphenyl Group 15 metal dichlorides (Ph3AsCl2, Ph3SbCl2 and Ph3BiCl2), with biologically active Lewis bases, lamivudine, a synthetic nucleoside, and camphoric acid, a dicarboxylic acid, to achieve synergistic effect.

Five classes of polymers were synthesized using interfacial polymerization: lamivudine and organotin dichlorides, lamivudine and Group 4 metallocene dichlorides, camphoric acid and triphenyl Group 15 metal dichlorides, camphoric acid and organotin dichlorides, and camphoric acid and Group 4 …

Napier Grass (Pennisetum Purpureum) Meal Modulates Growth Efficiency, Gut Morphology, And Systemic Health In Broiler Chickens, Eric Lim Teik Chung, Yee Lyn Ong, Nazri Nayan, Muhamad Faris Ab Aziz, Faez Firdaus Abdullah Jesse, Faizal Andri, Arissara Sopawong

The Thai Journal of Veterinary Medicine

Grass and leaf meals, which include vital phytocompounds, have the potential to be a natural and safe alternative to antibiotics in the poultry industry. Therefore, this study aims to assess Pennisetum purpureum leaf meal and its phytocompounds on the health performances of colored-broilers. A total of 216 unsexed Sasso chicks were assigned to six diet groups. The negative control (T1) received a commercial basal diet without antibiotics, while the positive control (T2) received the same diet with oxytetracycline (100 mg/kg). Groups T3 to T6 received no antibiotics and included P. purpureum meal at 1.25, 2.50, 3.75, or 5.00 grams per …

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 …

Immunomodulatory And Signaling Molecules From Plant-Associated Bacteria: Toll-Like Receptor 4 Agonist Adjuvants And Diketopiperazine-Mediated Communication, Marian Romaine

Dissertations, Theses, and Capstone Projects

Medicinal plants and their associated microbiomes constitute a rich source of bioactive natural products with applications in immunotherapy and microbial ecology. Herbal formulations have long been valued for safe immune enhancement, while bacterial signaling molecules govern community behaviors critical to pathogenesis, symbiosis, and environmental processes. Bacterial lipopolysaccharides (LPS) from plant-associated Gram-negative bacteria have emerged as potent TLR4 agonists, yet their endotoxic potential limits direct use, and diketopiperazines (DKPs) serve as versatile quorum-sensing mediators capable of modulating biofilms in mixed microbial systems.

The work in this thesis comprises two independent but complementary research strands. The first strand pursued the engineering of …

Identifying Textual Predictors Of Early Termination In Clinical Trials In Medicine: An Explainable Machine-Learning Study, Rohan Ramnarain

Dissertations, Theses, and Capstone Projects

About one in five clinical trials in medicine ends early, wasting valuable resources and reducing the evidence available for developing life-saving medical treatments. This project uses a method called Trial2Vec, which is a self-supervised machine-learning method that converts clinical trial documents into dense numerical representations that capture their key design and clinical characteristics, to turn each proposed clinical trial’s written protocol into a compact numerical profile (a process referred to as embedding). These profiles are then paired with a predictive machine learning models to identify the words and phrases in the trial documents that can signal a higher risk of …

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 …

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 …

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 …

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 …

Functionalized Nanodiamonds As Binding Platforms For Single-Stranded Dna, Mallory A. Chapman

Honors Theses

Nanodiamonds (NDs) offer a promising platform for biomolecular applications due to their stability, biocompatibility, and three-dimensional structure. This study focused on developing a nanodiamond–DNA complex in which streptavidin-functionalized NDs would form a protective shell around biotinylated single-stranded DNA (ssDNA), creating a core–shell system like an “M&M” candy with DNA at the center and a protective coating on the outside. DNA has many uses in nanotechnology, including DNA origami, nanomachines, and drug delivery systems, but its degradation limits its practical use, making protective strategies essential.

ND–DNA conjugates were prepared using biotin–streptavidin interactions and analyzed using gel electrophoresis. Initial separation on agarose …

Biochemical Characterization Of Luciferase In Omphalotus Olearius, James H. Martin

Honors Theses

The overall goal of this thesis was to investigate the genetic basis of bioluminescence in Omphalotus olearius, a bioluminescent mushroom. The project initially focused on growing fungal cultures under controlled laboratory conditions and using molecular techniques such as DNA extraction, PCR, and gel electrophoresis to identify the organism and isolate the gene responsible for light production. The main objective was to insert this gene into a bacterial system to confirm its function through observable bioluminescence. However, repeated difficulties in maintaining viable fungal cultures and errors in molecular procedures resulted in inconclusive results, preventing successful gene identification. Due to these …

Bioinformatic Resolution Of Candidate Stress-Response Homologs In Cryptosporidium Parvum: P53-Family Vs Sestrin Identity, Freeman Tobechukwu Ezeala Mr.

Biochemistry and Molecular Biology

Cryptosporidium parvum is an apicomplexan protozoan of major public-health importance, but accurate genome annotation in this organism remains difficult because of its compact genome, deep protein divergence, and the presence of compositionally biased or low-complexity regions that can mislead similarity-based analysis.

In this thesis, I examined one such annotation problem involving a conserved Cryptosporidium stress-response candidate protein, CPATCC_0028580_t1 (833 aa). The central question was whether this protein is better interpreted as a member of the p53 family, based on similarity to p53-like DNA-binding domains (PF00870), or as a member of the Sestrin family associated with the PA26 domain.

I explored …

Optimizing Expression Conditions For The Overexpression Of Iron Regulatory Protein Bol2 From C. Glabrata, Jade Ikahihifo-Bender, Dr. Caryn Outten, Mrs. Evan Talib

Caravel Undergraduate Research Journal

Due to its unique ability to serve as both an electron donor and acceptor, iron is utilized as a co-factor for many biological processes, including electron transfer, oxygen binding, and vitamin synthesis. Iron is also a key factor during fungal infections as the human host and invading pathogens battle over limited iron pools. The primary iron-responsive transcription factor Aft1 in the opportunistic pathogenic yeast Candida glabrata responds to iron deficiency by activating expression of iron acquisition genes. However, the mechanisms for sensing intracellular iron levels and regulating Aft1 activity in response to iron are unknown. The C. glabrata iron regulation …

The Universe Under A Microscope, Claire Chabot

Caravel Undergraduate Research Journal

No abstract provided.

Discovering The Southern Appalachian Grassy Balds, Nicholas Lenze

Caravel Undergraduate Research Journal

Grassy balds are unique Appalachian wonders, open meadows in the mountains where, ecologically, there should be trees. It has been hypothesized that some of the balds originated more than ten thousand years ago and were kept open by the grazing of large herbivores such as the mastodon and the wooly mammoth. Over the course of earth’s history, environmental and anthropogenic factors have shaped, modified and maintained the balds. Up to one hundred grassy balds were once recognized to exist in the southern Appalachians, but fewer exist today due to forest succession (Gersmehl, 1970). Collectively, the grassy balds share a common …

Isolation, Purification, And Characterization Of Α-Galactosidase From Watermelon (Citrullus Lanatus), Christopher Henley Jr.

Chemistry & Biochemistry Undergraduate Honors Theses

The enzyme α-galactosidase is a type of glycosidase that removes galactose sugar units from larger molecules in cells. Compounds that inhibit glycosidases have been useful for understanding the structure and function of the enzymes they inhibit, and some have been used to treat certain diseases. Using inhibitors of α-galactosidase to study its characteristics and mechanisms may provide insights into its role in disease and its general utility. Advances in fields such as agriculture, sustainable fuels, and biomedicine may be facilitated by inhibition studies of α-galactosidase, but the current library of known inhibitors is relatively lacking. Obtaining α-galactosidase enzymes from chemical …

Shark Immunology And Its Biomedical Potential: Evolution, Innovation, And The Imperative Of Conservation, Reesha Bhagat

Undergraduate Honors Thesis Collection

This review aims to shed light on a significant ecological deficit and its implications for the future of science and medicine. Sharks possess a uniquely adaptive, cancer-resistant, and evolutionarily refined immune system with transformative biomedical potential, making their conservation a scientific and medical imperative. We are losing something medically irreplaceable, and we don’t even fully understand it yet. Shark conservation is a pressing scientific imperative because sharks are ecologically essential and represent an irreplaceable biomedical resource.

Sequence Determinants Of Rna G-Quadruplex Unfolding By Arg-Rich Regions, Naiduwadura Ivon Upekala De Silva, Puspa Kunwar, Md Ibnul Rifat Rahman, Joanna Koryo Kwao, Nathan Lehman, Zihan Zhang, Trenton Paul, Claire Cheng, Nicholas Truex, Hui-Ting Lee, Jun Zhang

Faculty Publications

RNA sequences with the potential to form G-quadruplexes (rGQs) are widespread but largely unfolded in cells by unknown mechanisms. rGQ folding status is a critical regulator of RNA splicing and translation. We show that rGQs can be unfolded by SR proteins, SR-related proteins, and other Arg-rich proteins, including SRSF1, SRSF3, SRSF9, U1-70K, and U2AF1. The length and composition of Arg-rich regions are key determinants of this activity: Arg residues are the primary drivers, while acidic residues attenuate the unfolding activity. To unfold ARPC2 rGQ, at least 13 Arg residues are required. Our findings identify Arg-rich proteins as previously unrecognized, helicase-independent …

Evaluation Of Flt3 Inhibition With Quizartinib During Busulfan Conditioning For Hematopoietic Stem Cell Transplantation, Catherine Jankovic

Biochemistry and Molecular Biology

Hematopoietic stem cell transplantation (HSCT) is one of the only curative therapy options for many hematologic malignancies. HSCT relies on effective conditioning regimens to deplete host hematopoietic cells and enable donor engraftment. The alkylating agent Busulfan is widely used in myeloablative conditioning strategies due to its potent cytotoxic effects on hematopoietic cells and ability to clear the bone marrow. However, optimization of conditioning strategies remains an important area of investigation to improve transplant outcomes and reduce toxicity. Preliminary studies have shown that the FLT3 inhibitor Quizartinib synergizes with some chemotherapeutic agents, suggesting that targeted inhibitors may enhance conventional conditioning regimens. …

Acute Effects Of The Psychoactive Pollutant Fluoxetine On The Antipredator Behavior Of The Gulf Killifish (Fundulus Grandis), Semyra Reus

Honors Theses

Pharmaceutical contaminants are increasingly prevalent in aquatic environments, yet their sublethal effects on ecologically relevant behaviors remain poorly understood, particularly in estuarine systems. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are of particular concern due to the conserved role of serotonin in regulating behavior across vertebrates. Here, we investigated how acute exposure to environmentally relevant concentrations of fluoxetine influences anti-predator behavior in Gulf killifish (Fundulus grandis), a key estuarine fish commonly found in saltmarsh habitats. Killifish were exposed to control (0 ng/L), low (17.8 ng/L), and high (596 ng/L) fluoxetine concentrations and subsequently tested in the presence …

Understanding Tlr3 Immune Response Activation In Cryptosporidium Parvum And Cryspovirus Pathogenesis, Surayya Hudayberganova

Biochemistry and Molecular Biology

Cryptosporidiosis is a serious gastrointestinal illness caused by a protozoan parasite known as Cryptosporidium. It is particularly dangerous for malnourished children and those with compromised immune systems. My research focuses on the Toll-like receptor 3 (TLR3) response to the Cryptosporidium parvum infection, specifically in the presence of the parasite’s viral mutualist named cryspovirus (CSpV1). Results using research methodologies like ELISA and RT-qPCR have indicated that TLR3 expression increases during the infection process of Cryptosporidium parvum (C. parvum). Furthermore, one intriguing observation concluded during this study suggests that administering the TLR3-specific inhibitor CU-CPT4a to infected cells drastically decreased this activation. This …

Ethanol State-Dependent Learning In The Honey Bee (Apis Mellifera), Ethan Neil Govea

Theses and Dissertations

Ethanol disrupts neural circuits involved in addiction and withdrawal, yet the molecular mechanisms underlying these effects remain poorly understood. One possibility is that ethanol alters an animal’s perceptual or internal state, causing a stimulus learned while intoxicated to be processed differently when the animal is sober. This study examined how ethanol exposure affects odor learning, recall, and discrimination in honey bees, a useful model because of their robust olfactory learning and experimentally accessible neural systems. Bees were differentially conditioned with appetitive reward (sucrose) during hexanol exposure and aversive stimulus (quinine) during decanol exposure. To assess olfactory processing and state dependency, …

Identification Of Peptides For A Muc13 Cancer Vaccine, Abigail Olivia Gomez

Theses and Dissertations

Mucin 13 (MUC13) is a transmembrane glycoprotein that is frequently overexpressed in epithelial cancers. Its extracellular domains and cytoplasmic signaling potential contribute to disrupted cell adhesion, increased invasion, and cancer-promoting pathways, making MUC13 a promising target for immunotherapy. This project used an in-silico approach to identify MUC13-derived peptides predicted to bind HLA class I molecules and support CD8+ T cell-mediated immune responses. Bioinformatics tools were used to screen candidate epitopes for HLA binding affinity, antigenicity, toxicity, IFN-γ-inducing potential, and population coverage, allowing rational prioritization of peptide candidates for experimentation. Selected peptides were evaluated in THP-1-derived macrophages using RT-PCR, Western blotting, …