Biochemistry, Biophysics, and Structural Biology Commons^™

Reactive Oxygen Species-Mediated Neurodegeneration Is Independent Of The Ryanodine Receptor In Caenorhabditis Elegans, Lyndsay E.A. Young, Daniel C. Williams

Journal of the South Carolina Academy of Science

Despite the significant impacts on human health caused by neurodegeneration, our understanding of the degeneration process is incomplete. The nematode Caenorhabditis elegans is emerging as a genetic model organism well suited for identification of conserved cellular mechanisms and molecular pathways of neurodegeneration. Studies in the worm have identified factors that contribute to neurodegeneration, including excitotoxicity and stress due to reactive oxygen species (ROS). Disruption of the gene unc-68, which encodes the ryanodine receptor, abolishes excitotoxic cell death, indicating a role for calcium (Ca²⁺) signaling in neurodegeneration. We tested the requirement for unc-68 in ROS-mediated neurodegeneration using the …

Expression And Purification Of Unlabelled And Isotopically Labelled Human Fibroblast Growth Factor-1 And Its Receptor Relevance In Cancer Research, Oluwadamilola Filani

Masters Theses & Specialist Projects

Studies show that fibroblast growth factors (FGFs) control variety of cellular activities such as mitosis, cell differentiation, survival and angiogenesis. The FGF family consists of 23 different heparin-binding proteins. One of the most intensively studied members is human FGF-1 (hFGF-1) because of its critical role in the formation of blood vessels and cell proliferation in some types of cancer. The biological activities of FGFs are primarily mediated via interactions with fibroblast growth factor receptors (FGFR) and are a potent target in cancer. In this study, we report an efficient affinity column purification of hFGF-1 and the D2 domain of FGFR-2 …

Ionic Driven Embedment Of Hyaluronic Acid Coated Liposomes In Polyelectrolyte Multilayer Films For Local Therapeutic Delivery, Stephen L. Hayward, David M. Francis, Matthew J. Sis, Srivatsan Kidambi

Papers in Biomolecular Engineering

The ability to control the spatial distribution and temporal release of a therapeutic remains a central challenge for biomedical research. Here, we report the development and optimization of a novel substrate mediated therapeutic delivery system comprising of hyaluronic acid covalently functionalized liposomes (HALNPs) embedded into polyelectrolyte multilayer (PEM) platform via ionic stabilization. The PEM platform was constructed from sequential deposition of Poly-LLysine (PLL) and Poly(Sodium styrene sulfonate) (SPS) “(PLL/SPS)_4.5” followed by adsorption of anionic HALNPs. An adsorption affinity assay and saturation curve illustrated the preferential HALNP deposition density for precise therapeutic loading. (PLL/SPS)_2.5 capping layer on top …

Multi-Dimensional Glycan Microarrays With Glyco-Macroligands, Satya Nandana Narla, Huan Nie, Yu Li, Xue-Long Sun

Chemistry Faculty Publications

Glycan microarray has become a powerful high-throughput tool for examining binding interactions of carbohydrates with the carbohydrate binding biomolecules like proteins, enzymes, antibodies etc. It has shown great potential for biomedical research and applications, such as antibody detection and profiling, vaccine development, biomarker discovery, and drug screening. Most glycan microarrays were made with monovalent glycans immobilized directly onto the array surface via either covalent or non-covalent bond, which afford a multivalent glycans in two dimensional (2D) displaying. A variety of glyco-macroligands have been developed to mimic multivalent carbohydrate-protein interactions for studying carbohydrate-protein interactions and biomedical research and applications. Recently, a …

Ligand Frameworks For Transition-Metal Complexes That Model Metalloenzyme Active, Denan Wang

Dissertations (1934 -)

Advances in the field of biomimetic inorganic chemistry require the design of sophisticated ligand frameworks that reflect the amazing complexity of metalloenzyme active sites. For instance, most active sites feature extensive hydrogen-bonding interactions between ligands bound to the metal center (the “first” coordination sphere) and nearby units in the outer (or “second”) sphere. Since these interactions modify the structural and electronic properties of the active sites, a number of inorganic chemists have sought to design ligands that permit outer-sphere functional groups to interact with first-sphere donors. This dissertation describes our contribution to these broader efforts to model the second coordination …

Characterization Of Inhibitors Of Fatty Acid Transport Protein-2 In Cell And Animal Models, Nipun Saini

Department of Biochemistry: Dissertations, Theses, and Student Research

Obesity is correlated with insulin resistance and elevated levels of glucose, triglycerides and free fatty acids in blood. This affects overall metabolism and leads to disease. In the obese state, fat also accumulates in non-adipose tissue including liver, muscle and pancreas, where it can lead to cellular dysfunction and death. Currently, only a limited number of drugs are available to combat obesity and it is clear that new drugs, which more narrowly target the metabolic pathways involved, are required. Fatty Acid Transport Proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme …

Image-Charge Detection €“ Novel Instrumentation And Applications, Brandon Lee Barney

Theses and Dissertations

Image-charge detection is an analytical technique in which a highly-charged particle is detected by the magnitude of the image current that it generates in a detecting electrode. This current is represented as a voltage between the charged particle and the sensing electrode. It is a single particle detection method, ideal for the analysis of large, variable mass particles such as biological cells. Some of the physical properties of Bacillus subtilis spores were explored using different applications of image-charge detection. B. subtilis is a gram-negative spore-forming bacteria that has been shown to exhibit extremophile behavior. The particular extremophile behavior that was …

Cell Type–Dependent Mechanisms For Formin-Mediated Assembly Of Filopodia, Lorna E. Young, Ernest G. Heimsath, Henry N. Higgs

Dartmouth Scholarship

Filopodia are finger-like protrusions from the plasma membrane and are of fundamental importance to cellular physiology, but the mechanisms governing their assembly are still in question. One model, called convergent elongation, proposes that filopodia arise from Arp2/3 complex-nucleated dendritic actin networks, with factors such as formins elongating these filaments into filopodia. We test this model using constitutively active constructs of two formins, FMNL3 and mDia2. Surprisingly, filopodial assembly requirements differ between suspension and adherent cells. In suspension cells, Arp2/3 complex is required for filopodial assembly through either formin. In contrast, a subset of filopodia remains after Arp2/3 complex inhibition in …

Mutations Of Adjacent Amino Acid Pairs Are Not Always Independent, Jyotsna Ramanan, Peter Revesz

School of Computing: Conference and Workshop Papers

Evolutionary studies usually assume that the genetic mutations are independent of each other. This paper tests the independence hypothesis for genetic mutations with regard to protein coding regions. According to the new experimental results the independence assumption generally holds, but there are certain exceptions. In particular, the coding regions that represent two adjacent amino acids seem to change in ways that sometimes deviate significantly from the expected theoretical probability under the independence assumption.

Dna Repair Deficiency In Huntington's Disease Fibroblasts And Induced Pluripotent Stem Cells, Peter Anthony Mollica

Biological Sciences Theses & Dissertations

Mutant huntingtin protein (mhtt)– the protein responsible for cellular dysfunction in Huntington’s disease (HD) –is a product of an expanded trinucleotide repeat (TNR) cytosine-adenine-guanine (CAG) sequence in exon 1 of the huntingtin (HTT) gene. The pathology of HD has been extensively researched; however, the mechanism by which the disease-causing TNR expansions occur in somatic cells remains elusive. Interestingly, HD has often been referred to a ‘DNA repair disease’, even though DNA repair dysfunction in situ has not been identified. We hypothesized that presence of the mhtt protein affects the expression of DNA repair genes used to address DNA repair, ultimately …

Biophysical Properties Of Cellular Membranes In Gram-Positive Bacterial Pathogens And Their Impact On Major Physiological Attributes And Virulence Determinants, Suranjana Sen

Theses and Dissertations

The cytoplasmic membrane of bacterial cells, forming an essential barrier from the surroundings, is a critical component of cellular physiology ensuring proper survival and maintenance of major cellular functions. The integrity of the membrane is an important feature that plays an essential role in the transport of solutes and nutrients through active and passive pathways, functions of membrane-associated proteins, electron transport and ATP synthesis, maintaining turgor pressure and combating environmental stresses, and thus is a crucial factor of a majority of cellular adaptations. The various biophysical properties affecting the integrity of this membrane are mainly determined by the composition and …

Incipient Speciation In Freshwater Fish Species From Two Isolated Watersheds, Paula Gore Miller

Dissertations, Theses, and Capstone Projects

The process of speciation occurs as a result of restricted gene flow between segments of an interbreeding population occupying different geographic areas. This separation may result in isolated populations which undergo genetic and phenotypic changes. The Wisconsin glacial period, which ended approximately 17,500 years ago, dramatically altered the geography of North America. The glacier covered almost the entire North America as it advanced. Areas that were not covered with ice provided suitable habitats (refugia) for relict species that were previously widespread in the northern section of the continent. As the ice sheet retreated, animals and plants were able to return …

Exploiting Cancer Cell Signaling And Metabolism: Implications For Therapeutic Approach, Suman Mukhopadhyay

Dissertations, Theses, and Capstone Projects

Over the last decade, metabolic dysregulation in cancer cells has stimulated a significant amount of interest in basic research. It has been established that cancer cells increase glucose uptake and alter the fate of glycolytic and tricarboxylic acid (TCA) cycle intermediates for the synthesis of biological molecules to accommodate high rates of cellular growth and proliferation. Moreover, it is more prominent that some metabolic dysregulations are specific to particular oncogenes. Exploiting the dysregulated metabolic dependency of cancer cells with therapeutic means could represent a novel approach for clinical aspect.

To meet the need of increased anabolic metabolism cancer cells engage …

Exploring Chromatin-Bound Mdm2 Functions In Compromised Transcriptional Regulation Of P53 Target Genes, Melissa Rosso

Dissertations, Theses, and Capstone Projects

MDM2 overexpression is a common occurrence in many types of cancer. A single nucleotide polymorphism (T to G) near the mdm2 promoter, termed mdm2 SNP309, leads to MDM2 overexpression. This polymorphism is associated with accelerated tumor formation, decreased sensitivity to DNA damage treatment and compromised p53 transcriptional activity. Two G/G SNP309 cancer cell lines MANCA and A875, a Burkitts' lymphoma and melanoma respectively, express a stable wild-type p53 protein. We previously reported these cells have DNA damage resistant MDM2-p53 chromatin complexes and hypothesized that MDM2 is the contributing factor for the compromised p53 transcriptional activity. We created constitutive mdm2 shRNA …

Characterizing Migratory Signaling Pathways Of Transplantable Retinal Progenitor Cells And Photoreceptor Precursor Cells Toward Restoration Of Degenerative Retina ' A Systems Biology Approach, Uchenna John Unachukwu

Dissertations, Theses, and Capstone Projects

A common feature of several heterogeneous diseases that result in retinal degeneration (RD) is photoreceptor loss, leading to an irreversible decline in visual function [15-17]. There are no cell replacement treatments available for RD diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). Although many RD cases are of a genetic origin, a promising strategy to treat diseased phenotypes is by replacing lost photoreceptor cells, for synaptic integration and restoration of visual function. To advance photoreceptor-replacement strategies as a practical therapy, in light of highly restricted integration rates reported across studies, this body of research focused on defining …

Knowledge Discovery And Prediction Modeling Of Protein-Drug Binding Kinetic By Integrating Machine Learning, Normal Mode Analysis And Molecular Dynamics Simulation, See Hong Chiu

Dissertations, Theses, and Capstone Projects

One of the unaddressed challenges in drug discovery is that drug potency measured by protein-ligand binding affinity, such as IC₅₀ and K_d in vitro, is not correlated with drug activity in vivo. Computational modeling is playing an increasing role in designing efficient therapeutics. However, existing computational methods for the high-throughput study of protein-ligand interactions (PLI) mainly focus on the prediction of the binding affinity. This is the combined effect of association (k_on) and dissociation (k_off) rate constants. Few works have been produced to predict koff or its reciprocal, residence time, which is a key …

Biophysical Characterization Of A De Novo Elastin, Kelly Nicole Greenland

Dissertations, Theses, and Capstone Projects

Natural human elastin is found in tissue such as the lungs, arteries, and skin. This protein is formed at birth with no mechanism present to repair or supplement the initial quantity formed. As a result, the functionality and durability of elastin's elasticity is critically important. To date, the mechanics of this ability to stretch and recoil is not fully understood. This study utilizes de novo protein design to create a small library of simplistic versions of elastin-like proteins, demonstrate the elastin-like proteins, maintain elastin's functionality, and inquire into its structure using solution nuclear magnetic resonance (NMR).

Elastin is formed from …

The Role Of Atp And Cleavage Factor Phosphorylation In Pre-Mrna 3' Cleavage Reaction, Asya Khleborodova

Dissertations, Theses, and Capstone Projects

The 3' end cleavage/polyadenylation (3' processing) is important in generating a functional messenger RNA (mRNA) transcript. It is long-known that ATP can significantly stimulate the in vitro cleavage of adenovirus type 2 L3 (Ad2L3) RNA substrate. Here, we used ATP analogs in structure-activity assays to show that the structural features of ATP and its analogs determine in vitro 3' cleavage efficiency. More specifically, we demonstrate that the structure of the nitrogenous base, the nucleotide sugar and the triphosphate group contribute to the efficiency of the nucleotide-stimulated in vitro 3' cleavage reaction.

It was found that AppNp, an analog of ATP …

Regulation Of The Vacuolar Atpase Activity, Paulina Konarzewska

Dissertations, Theses, and Capstone Projects

In eukaryotes, V-ATPases play an essential role in cellular pH homeostasis as they transport hydrogen ions into the vacuoles. This assures an acidic vacuolar interior and normal physiological processes associated with this organelle. Studies show that mutations in any of the VMA genes encoding for subunits of the V-ATPase pump result in growth inhibition in the absence of inositol, suggesting that V-ATPases may play an important role in phospholipid biosynthesis or vice versa. It is not clear how VMA genes affect phospholipid biosynthesis and how the regulators of phospholipid biosynthetic genes may affect ATPase activity. Here, we employ biochemical and …

Fatty Acid Transport Protein-2 Inhibitor Grassofermata/Cb5 Protects Cells Against Lipid Accumulation And Toxicity, Nipun Saini, Paul N. Black, David Montefusco, Concetta Dirusso

Department of Biochemistry: Faculty Publications

The inhibition of the fatty acid uptake into non-adipose tissues provides an attractive target for prevention of lipotoxicity leading to obesity-associated non-alcoholic fatty liver disease and type 2 diabetes. Fatty acid transport proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme A. Here we characterize Grassofermata/CB5, previously identified as a fatty acid uptake inhibitor directed against HsFATP2. The compound was effective in inhibiting the uptake of fatty acids in the low micro-molar range (IC₅₀ 8–11μM) and prevented palmitate-mediated lipid accumulation and cell death in cell lines that are models for …

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O₃(g) by catechol γ_O3 = (7.49 ± 0.35) × 10^–6 occurs for …

Genomic Deoxyuracil: Targeting, Regulation And Repair, Nate Warren Holton

Theses and Dissertations

Maintaining genomic integrity is critical to avoid sequence mutations and genetic disease. However the immune system requires genomic rearrangements in order to produce novel antibodies and illicit a full immunological response. The expression of DNA modifying enzymes is essential for antibody production but the off target effects are not well understood. The work presented here was performed to elucidate molecular mechanisms responsible for the regulation and targeting of DNA editing enzymes, as well as characterize repair of these lesions at off target loci.

Alternative Strategies In Response To Saline Stress In Two Varieties Of Portulaca Oleracea (Purslane), Dana A. Dudle, Kristina R. Mulry, Bryan A. Hanson

Biology Faculty publications

Purslane (Portulaca oleracea) is a globally-distributed plant with a long history of use in folk medicine and cooking. We have developed purslane as a model system for exploring plant responses to stress. We exposed two varieties of purslane to saline stress with the objective of identifying differences between the varieties in the plasticity of morphological and physiological traits. The varieties responded to saline stress with significantly different changes in the measured traits, which included inter alia biomass, flower counts, proline concentrations and betalain pigment concentrations. The alternative responses of the two varieties consisted of complex, simultaneous changes in …

Elongation Factor-P At The Crossroads Of The Host-Endosymbiont Interface, Andrei Rajkovic, Anne Witzky, William Navarre, Andrew J. Darwin, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Elongation factor P (EF-P) is an ancient bacterial translational factor that aids the ribosome in polymerizing oligo-prolines. EF-P structurally resembles tRNA and binds in-between the exit and peptidyl sites of the ribosome to accelerate the intrinsically slow reaction of peptidyl-prolyl bond formation. Recent studies have identified in separate organisms, two evolutionarily convergent EF-P post-translational modification systems (EPMS), split predominantly between gammaproteobacteria, and betaproteobacteria. In both cases EF-P receives a post-translational modification, critical for its function, on a highly conserved residue that protrudes into the peptidyl-transfer center of the ribosome. EPMSs are comprised of a gene(s) that synthesizes the precursor molecule …

Mechanistic Insights Into Glucan Phosphatase Activity Against Polyglucan Substrates, David A. Meekins, Madushi Raththagala, Kyle D. Auger, Benjamin D. Turner, Diana Santelia, Oliver Kötting, Matthew S. Gentry, Craig W. Vander Kooi

Molecular and Cellular Biochemistry Faculty Publications

Glucan phosphatases are central to the regulation of starch and glycogen metabolism. Plants contain two known glucan phosphatases, Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2), which dephosphorylate starch. Starch is water-insoluble and reversible phosphorylation solubilizes its outer surface allowing processive degradation. Vertebrates contain a single known glucan phosphatase, laforin, that dephosphorylates glycogen. In the absence of laforin, water-soluble glycogen becomes insoluble, leading to the neurodegenerative disorder Lafora Disease. Because of their essential role in starch and glycogen metabolism glucan phosphatases are of significant interest, yet a comparative analysis of their activities against diverse glucan substrates has not been established. …

Photoacoustic Calorimetry Studies Of The Earliest Events In Horse Heart Cytochrome-C Folding, Tarah A. Word

USF Tampa Graduate Theses and Dissertations

The protein folding problem involves understanding how the tertiary structure of a protein is related to its primary structure. Hence, understanding the thermodynamics associated with the rate-limiting steps for the formation of the earliest events in folding is most crucial to understanding how proteins adopt native secondary and tertiary structures. In order to elucidate the mechanism and pattern of protein folding, an extensively studied protein, Cytochrome-c (Cc), was chosen as a folding system to obtain detailed time-resolved thermodynamic profiles for the earliest events in the protein folding process. Cytochrome-c is an ideal system for understanding the folding process for several …

A Forward Genetic Screen Identifies Factors Associated With Fever Pathogenesis In Plasmodium Falciparum, Phaedra J. Thomas

USF Tampa Graduate Theses and Dissertations

Infectious diseases that spread from person-to-person and continent-to-continent are a cause for concern for any health entity. One such disease is malaria, a mosquito-borne infection instigated by the protozoan parasite, Plasmodium falciparum. Hundreds of millions of people are affected annually and it is responsible for nearly 1 million deaths. It is the most fatal species causing malaria and proliferates in human red blood cells with a life cycle occurring every 48 hours. At this time, the parasite’s late stage form or schizont bursts from the erythrocyte releasing immune-inducing particles and infective forms (merozoites) into the bloodstream. The merozoites go …

Function Of Long Noncoding Rnas In Breast Cancer, Edward J. Richards

USF Tampa Graduate Theses and Dissertations

Breast cancer is a disease that will be diagnosed in about 1 in 10 women throughout their lifetime. The majority of breast cancers are originated from the epithelial cells of the mammary ducts, and this occurrence can be due to several factors including hereditary and acquired mutation. There are several major breast cancer subtypes, including estrogen receptor-α (ERα)-positive, HER2-enriched and triple-negative (TNBC). Patients diagnosed with ER+ tumors are generally treated with estrogen blockers (e.g., tamoxifen, letrozole and fulvestrant). Patients with HER2+ tumors are commonly administered with drugs that block HER2 signaling (e.g., trastuzumab) or inhibit HER2’s tyrosine kinase activity (e.g., …

Evaluation Of Reproductive Strategies In Captive California Yellowtail (Seriola Dorsalis) Using Genetic Parentage Analyses, Elizabeth K. Smith, Mark Drawbridge Ms, John Hyde Phd, Geoffrey Morse Phd

Theses

A good understanding of spawning dynamics of species in aquaculture is vital in order to maximize egg production and quality as well as efficient allocation of food and space resources. The breeding program of California yellowtail (CYT; Seriola dorsalis previously Seriola lalandi) at Hubbs-SeaWorld Research Institute (HSWRI) is set up such that up to 30 wild caught brood fish can broadcast spawn in a group setting, just as CYT reproduce in the wild. The population of brood fish were originally caught offshore from Southern California, and are maintained under ambient sea water and natural lighting conditions. The spawning season …

Characterizing The Rogfp2-Orp1 Fluorescent Biosensor For Detecting Oxidative Stress In Mammalian Cells, Sara A. Doan, Stevie Norcross, Mathew Tantama

The Summer Undergraduate Research Fellowship (SURF) Symposium

Parkinson’s disease is a neurodegenerative disease involving the death of neurons in the substantia nigra and loss of the neurotransmitter, dopamine. The disease leads to progressive loss of motor control. Exact causes and mechanisms by which Parkinson’s disease proceeds are unknown, however, previous experiments determine oxidative stress in mitochondria as a factor that results in cell death. Strategies have been implemented to generate fluorescent biosensors to monitor reactive oxygen species (ROS) concentrations while simultaneously measuring the spatiotemporal distribution and correlation between the ROS, cellular function and organelle. Orp1, an enzyme found in yeast, is a sensitive oxidizing species and when …