Biochemistry Commons^™

Long-Term Antibacterial Efficacy Of Silver (I) Cyanoximates Against Streptococcus Mutans Ua159 Biofilm Growth, Tiffany A. Rojas

Honors Program Theses

Streptococcus mutans is the primary causative agent of dental caries due to its ability to form resilient multispecies biofilms. These biofilms promote acid production and degradation of the protective layers of the tooth, making biofilm formation a target for novel treatments. Silver(I) cyanoximates are of interest as alternatives to traditional antimicrobials and antibiotics due to the high UV and heat resistivity as well as poor solubility of the cyanoxime ligand paired with the well-established antimicrobial silver ion. Previous research has shown that silver(I) cyanoximates can effectively inhibit S. mutans biofilm formation after 24 hours in vitro. This study aimed to …

Target Cell-Associated Cd47 Suppresses Nadph Oxidase Activity In Macrophages During Antibody Dependent Cellular Phagocytosis, Seuly Akter

Electronic Theses and Dissertations

CD47-SIRPα signaling is a well-known immune checkpoint that suppresses macrophage-mediated antibody-dependent cellular phagocytosis (ADCP). In this study, we explored how CD47 influences reactive oxygen species (ROS) production driven by Fcγ receptor (FcγR) signaling. Our results show that macrophages produce significantly more ROS when encountering IgG coated target cells lacking CD47.Polarization with IFNγ further amplified this effect. ThusCD47-SIRPα interactions limit phagocytosis and suppress oxidative ROS production by macrophages. We found that CD47 blockade and IFNγ stimulation enhanced ADCP through distinct mechanisms. CD47 blockade removed the inhibitory "don't eat me" signal supporting ADCP and ADROS. Similarly, IFNγ enhances ADCP by upregulating FcγRI …

Characterization Of Lipids In Tenebrio Molitor Larvae And Pupae Under Various Extraction Methods, Nariman A. Ktil

Graduate Theses, Dissertations, and Problem Reports (ETD)

Tenebrio molitor, or the yellow mealworm is an edible insect widely recognized and consumed for its rich nutritional value. Mealworms are known for their flexible nature of adapting to various environmental conditions and being able to thrive under harsh conditions and low-value wastes. In this paper, our main goal was to investigate the mealworm’s ability to grow and develop while being reared on apple pomace, the biowaste from apple production, and the effect it would have on its nutritional value specifically its lipid profile. Then these reared insects were used for oil extraction and analyzing their fatty acid profiles. …

P23h Rhodopsin Accumulation Disrupts Synaptic Protein Levels In Rod Photoreceptors, Samantha Thompson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Rod photoreceptors are specialized neurons located in the retina, the neural tissue that lines the back of the eye. Rod photoreceptors are necessary for dim light and peripheral vision through the photoactivation rhodopsin (Rho). Rho is synthesized in the inner segment of rods before being unidirectionally trafficked to the outer segment. In diseases such as retinitis pigmentosa (RP), Rho trafficking can be disrupted, leading to progressive rod cell death. In many cases of RP, Rho is mislocalized to the rod photoreceptor synapse (“spherule”). The impact of Rho mislocalization on spherule structure and protein organization is poorly understood. We hypothesize that …

Ciliary Arl14b In Vision, Alexis Breann Crockett

Graduate Theses, Dissertations, and Problem Reports (ETD)

Primary cilia are highly specialized organelles that regulate signaling, trafficking, and sensory perception across multiple tissues, including the retina. The small GTPase ADP Ribosylation Factor-Like Protein 13B (ARL13B) is an atypical ARF-family protein enriched in cilia. ARL13B acts as a guanine exchange factor (GEF) for another small GTPase ARF-like Protein 3 (ARL3). Mutations in ARL13B cause Joubert syndrome, a ciliopathy characterized by brain malformation, developmental delays, and retinal degeneration. Despite ARL13B’s known ciliary localization and clinical relevance, ARL13B’s precise functions in cilia remain poorly defined. This dissertation investigates the cilia-specific roles and GEF-specific roles of ARL13B in photoreceptors using two …

Bridging The Gap Between Structural And Cellular Biology: Insight Into The Organization Of Glycolytic Enzymes In Cells, Heather Hansen

Graduate Theses, Dissertations, and Problem Reports (ETD)

Glycolytic enzymes are spatially organized in the cytoplasm, and are shown to localize with cellular structures such as the plasma membrane, F-actin, mitochondria, or associate independently within the cytosol. The assembly of these enzymes is hypothesized to regulate pathway flux to meet the energetic needs of the cell. However, it is unclear whether all of these assemblies have the same mechanism of formation or function in the cell. We investigated the role of glycolytic enzyme assemblies in cells, using the glycolytic “gatekeeper” enzyme phosphofructokinase-1 (PFK1). PFK1 is extensively regulated by multiple mechanisms, including over 20 allosteric ligands, post translational modifications, …

Probing The 10-23 Dnazyme Catalytic Core: Insights From Structural And Mechanistic Studies, Evan Rhyse Cramer

Graduate Theses, Dissertations, and Problem Reports (ETD)

The 10-23 DNAzyme is a catalytically active DNA oligonucleotide capable of cleaving RNA at purine-pyrimidine junctions in the presence of divalent metal ions, most notably magnesium. Despite its promise as a programmable RNA knockdown tool, its clinical and biotechnical utility has been hampered by limited structural characterization, low catalytic efficiency under physiological conditions, and poor understanding of its in-cell activity. This dissertation presents a comprehensive framework for the structural and functional analysis of DNAzymes using the 10-23 DNAzyme as a model system. In the absence of high-resolution structures, we first employed detailed in vitro biochemical assays to map essential residues …

Extracellular Vesicles Released By All Patients Contain Hne-Adducted Proteins: Implications Of Collateral Damage, Jenni Ho, Suriyan Sukati, Tamara Taylor, Sherry Carter, Brittany Fuller, Amy Marmo, Caryn Sorge, John A. D'Orazio, D. Allan Butterfield, Subbarao Bondada, Heidi Weiss, Daret K. St. Clair, Luksana Chaiswing

Markey Cancer Center Faculty Publications

Off-target neuronal injury is a serious side-effect observed in cancer survivors. It has previously been shown that pediatric acute lymphoblastic leukemia (ALL) survivors have a decline in neurocognition compared to healthy age-matched counterparts. Elevated oxidative stress has been documented to be a mediator in off- target tissue damage in cancer survivors. Early detection of oxidative stress markers may provide an opportunity to prevent off-target tissue damage. Extracellular vesicles (EVs) have surfaced as a potential diagnostic tool due to molecular cargo they contain. We investigated the potential for EVs to be a sensitive indicator of oxidative stress and off-target tissue damage …

The Adiponectin-Pparγ Axis In Hepatic Stellate Cells Regulates Liver Fibrosis, Shangang Zhao, Qingzhang Zhu, Wang-Hsin Lee, Jan-Bernd Funcke, Zhuzhen Zhang, May-Yun Wang, Qian Lin, Bianca Field, Xue-Nan Sun, Guannan Li, Mbolle Ekane, Toshiharu Onodera, Na Li, Yi Zhu, Christine M. Kusminski, Terry D. Hinds Jr., Philipp E. Scherer

Markey Cancer Center Faculty Publications

Hepatic stellate cells (HSCs) are key drivers of local fibrosis. Adiponectin, conventionally thought of as an adipokine, is also expressed in quiescent HSCs. However, the impact of its local expression on the progression of liver fibrosis remains unclear. We recently generated a transgenic mouse line (Lrat-rtTA) that expresses the doxycycline-responsive transcriptional activator rtTA under the control of the HSC-specific lecithin retinol acyltransferase (Lrat) promoter, which enables us to specifically and inducibly overexpress or eliminate genes in these cells. The inducible elimination of HSCs protects mice from methionine/choline-deficient (MCD) diet-induced liver fibrosis, confirming their causal involvement in fibrosis development. We generated …

Urobilin Derived From Bilirubin Bioconversion Binds Albumin And May Interfere With Bilirubin Interacting With Albumin: Implications For Disease Pathology, Kevin I. Williams, Priyanka Suryadevara, Chang-Guo Zhan, Terry D. Hinds Jr., Zachary A. Kipp

Markey Cancer Center Faculty Publications

Background/Objectives: Bilirubin is a hydrophobic molecule that binds the carrier protein albumin for transport through systemic circulation. Bilirubin is cleared from the body through the liver and excreted into the intestines, where the microbiota modifies the chemical structure, forming urobilin, which can be reabsorbed into circulation by the hepatic portal vein. Urobilin has no known function. It is also unknown whether urobilin binds albumin for transport in circulation. We hypothesized that because of the likeness of their chemical structures, urobilin would also bind albumin like bilirubin does. Methods: First, we used in silico docking to predict if urobilin would bind …

Dissecting The Biophysical Mechanisms Of Oleate Hydratase Association With Membranes, William A. Lathram, Robert J. Neff, Ashley N. Zalla, James D. Brien, Vivekanandan Subramanian, Christopher D. Radka

Markey Cancer Center Faculty Publications

This study investigates the dynamics of oleate hydratase (OhyA), a bacterial flavoenzyme from Staphylococcus aureus, and its interactions with lipid membranes, focusing on the factors influencing membrane binding and oligomerization. OhyA catalyzes the hydration of unsaturated fatty acids, playing a key role in bacterial pathogenesis by neutralizing host antimicrobial fatty acids. OhyA binds the membrane bilayer to access membrane-embedded substrates for catalysis, and structural studies have revealed that OhyA forms oligomers on membrane surfaces, stabilized by both protein-protein and protein-lipid interactions. Using fluorescence correlation spectroscopy (FCS), we examined the effects of membrane curvature and lipid availability on OhyA binding to …

Structural Insights Into Peptidoglycan O-Acetylation In Gram-Negative Bacteria, Tyler Malloch

Theses and Dissertations (Comprehensive)

The Centres for Disease Control has acknowledged that we are entering a post-antibiotic era, where increasing numbers of bacterial pathogens are becoming resistant to known antibiotics. One of the most successfully targeted features of bacteria is also the main component of the cell wall, peptidoglycan (PG). PG is a heteropolymer of alternating sugar residues, namely N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) which are joined together by b-(1,4)-glycosidic bonds and crosslinked via stem peptide chains. PG is a target, readily lysed by exogenous and endogenous autolysins, such as lysozyme and lytic transglycosylase, respectively. This event leads to cell death …

Characterizing The Targeting Of Toc159 Receptors To The Chloroplast Outer Envelope Membrane And Their Role In The Assembly Of Distinct Toc Complexes, Michael Fish

Theses and Dissertations (Comprehensive)

Global agriculture and food security face challenges from climate change, population growth, and other human-driven pressures. Enhancing our understanding of plant biology, particularly chloroplast function, is critical for improving crop yield and stress resilience. As the sites of photosynthesis and key regulators of plant responses to environmental cues, chloroplasts depend on the precise import of thousands of nuclear-encoded proteins to maintain their biogenesis and function. While much is known about the core translocon components in the chloroplast outer envelope membrane that form the TOC complex, the mechanisms underlying their targeting, assembly, and regulation remain incompletely understood.

Plastids, including chloroplasts, evolved …

Validating A Novel Capability Of Assessing Pathways Of Animal Water Gain And Loss, Zachary T. Steele, Karen Caceres, Zachary A. David, Lisa M. Shollenberger, Alexander R. Gerson, Seth D. Newsome, John P. Whiteman

Biological Sciences Faculty Publications

Understanding variations in the routes by which wild animals gain and lose water is challenging, and common methods require longitudinal sampling, which can be prohibitive. However, a new approach uses Δ′¹⁷O_BW (Δ′¹⁷O of animal body water), calculated from measurements of δ′¹⁷O and δ′¹⁸O in a single sample, as a natural tracer of water flux. Δ′¹⁷O_BW is promising, but its relationship to organismal variables such as metabolic rate and water intake have not been validated. Here, we continuously measured oxygen influxes and effluxes of captive deer mice (Peromyscus maniculatus), and manipulated their water intake and metabolic rate. We used …

Development Of Dna Nanoswitches With Aptamer Based Detection For Thrombin, Camryn A. Beckles

Electronic Theses & Dissertations (2024 - present)

Bio-transducers are devices capable of converting the binding signals from molecular recognition events into readable signals for analytical detection. There is a need for modular bio-transducers that can specifically detect a wide range of analytes using a unified readout technique, as this approach could dramatically reduce costs of healthcare diagnostics and environmental monitoring.

To create such a modular transducer, the molecular recognition properties of aptamers will be used and integrated with the already established biosensing capabilities of DNA nanoswitches that reconfigure their shape in the presence of their target molecule. In this design, the detector strands of the nanoswitch will …

Physiological Structure, Activity, And Interactions Of The Formin, Human Diaphanous Homologue 1, Aaron Premo

Electronic Theses & Dissertations (2024 - present)

Human Diaphanous Homologue 1 (DIAPH1) is a 143 kDa functional protein that plays a critical role in the regulation of actin dynamics within eukaryotic cells. As a formin, DIAPH1 facilitates the assembly of actin filaments from globular actin monomers, a process essential for cellular structure, motility, and other fundamental cellular processes. Beyond its structural role in actin polymerization, DIAPH1 is implicated in several diseases, including diabetes, cancer, and inflammation, as well as complications like hearing loss. Despite its significance in human health, the functional and structural properties of DIAPH1, particularly in human cells, remain less explored compared to related proteins, …

Technological Development Of In-Cell Nmr: Microfluidic, Metabolomic, And Fluxomic Approaches, Nicholas Sciolino

Electronic Theses & Dissertations (2024 - present)

In the fields of structural biology, metabolomics, and fluxomics, there is a driving, technique-based concern when it comes to high-resolution spectrometry and its marriage to biological and physiological relevance. Sample preparation often involves cellular perturbation, lysate separation schemes, combinations with non-biological reagents, and timeline slack. Conceptually, the farther we get from the cell, the greater the potential disparity between what exists in vivo and our in vitro manipulations. This is particularly true when seeking to collect data on transfected targets of interest, and on sensitive metabolic equilibria that occur on the order of minutes. The question remains: if we are …

The Bacteriostatic, Regenerative, And Immunomodulatory Properties Of Extracellular Matrix Particles For Lung Injury, Keera P. Rhoads

Theses and Dissertations

Acute respiratory distress syndrome (ARDS) is a prevalent, life-threatening lung condition, affecting nearly 200,000 Americans annually, with a 40% international mortality rate. There is no cure for ARDS, and current pharmacological treatments have limited effectiveness. Symptoms can be mitigated with mechanical ventilation, though this often leads to ventilator-induced lung injuries (VILI) and puts critically ill patients at risk of infections, including ventilator-associated pneumonia (VAP). A promising therapeutic is the extracellular matrix (ECM), a complex network of structural proteins and bioactive molecules that has been shown to have anti-inflammatory properties and prevent fibrosis. We aim to utilize the regenerative and immunomodulatory …

Unleashing Serine Palmitoyltransferase In Test Tubes And Mice, Matthew W. Peart

Theses and Dissertations

Canonically known both for structural contributions to lipid bilayers and roles in cell signaling, the sphingolipids comprise a dynamic, multifaceted class of molecules which are studied to understand homeostatic cell biology as well as pathophysiology. Sphingolipids contribute to tissue-specific structures such as myelin, a multilayer membrane that allows for rapid conduction of action potentials along neuronal axons. All sphingolipids are downstream products of the rate-limiting and initiating enzyme in the de novo sphingolipid synthesis pathway, Serine palmitoyltransferase (SPT). Demonstrative of its status as the enzyme that catalyzes a crucial step in a biochemical pathway, SPT activity is strictly regulated. This …

Bacteria-Engineered Vesicles For Cancer Immunotherapy: From Immunomodulation In Vitro To Anti-Tumor Effects In Melanoma Models, Lan Li

Theses and Dissertations--Chemistry

Bacterial vesicles hold immense potential in various biomedical fields. Among these, outer membrane vesicles (OMVs) produced by Gram-negative bacteria are the most extensively studied. While the exact mechanism of OMV production remains unclear, numerous environmental factors have been shown to influence both their yield and composition. In this study, we investigated the effect of three different antimicrobial families on OMV production by E. coli. Interestingly, antimicrobials within the same family did not provide the same effects on OMV yield, suggesting that OMV production may not directly correlate with the antimicrobial mechanism of action. OMVs have demonstrated tumor-inhibitory activity in multiple …