Biochemistry, Biophysics, and Structural Biology Commons^™

Development Of Antiviral Peptidomimetics, Songyi Xue

USF Tampa Graduate Theses and Dissertations

Protein-protein interactions (PPIs) are essential for biological processes and are associated with a number of diseases, including cancer, infectious diseases, and neurodegenerative diseases. As a result, modulation of PPIs has been recognized as one of the most promising strategies to develop the novel drugs. Peptide modulators always exhibit higher specificity and affinities with targets than small compounds or monoclonal antibodies, but their broad medicinal effectiveness is constrained by their poor bioavailability and biostability. Peptidomimetics, which have been developed to mimic the structure as well as function of bioactive peptides and proteins, have shown excellent potential in protein surface mimicry and …

Role Of Short Interspersed Nuclear Elements (Sines) Of Maternally Imprinted Microrna Clusters In Hemochorial Placental Antiviral Immunity, Ishani Wickramage

USF Tampa Graduate Theses and Dissertations

The evolution of hemochorial placentas in which the fetal trophoblast is bathed in maternal blood has vastly improved fetal development and survival in primates and rodents, due to the enhanced efficiency of nutrient, gas and waste exchange between the mother and the fetus. However, the extensive contact between the fetal tissues and maternal blood in these placentas also poses an increased risk of vertical transmission of pathogens such as viruses from the mother to the fetus. In response to this selection pressure, hemochorial placentas have evolved robust defense mechanisms to protect the immunologically naive fetus. Unlike somatic cells that require …

Defining A Factor-Induced Signaling Signature For Endothelial Tubulogenesis, Sprouting, And Pericyte Recruitment, Prisca Kuanting Lin

USF Tampa Graduate Theses and Dissertations

Endothelial cells (ECs) form the inner lining of blood capillary walls. Our laboratory has developed a serum-free, defined Factor system that allows for human ECs to sprout, form lumens and tube networks, recruit pericytes, and induce capillary basement membrane deposition in 3D extracellular matrices. We have shown that the Factor system drives morphogenesis through the activation of multiple signaling pathways; however, we do not know if all factors in the Factor system are needed to induce maximal EC morphogenesis. If so, we have yet to identify why the Factors are critical to the model other than that they induce activation …

Novel Roles Of The Blm Syndrome Dna Helicase In Genome Maintenance And Mitochondrial Regulation, Brian B. Rodemoyer

USF Tampa Graduate Theses and Dissertations

Bloom syndrome (BS) is an extremely rare autosomal recessive genetic disorder caused by defects in the BLM gene. Patients with BS display a broad phenotypic spectrum including abnormally short stature, microcephaly, sun sensitivity, insulin resistance, perpetual oxidative stress, and a ~300-fold greater propensity for developing cancer than the general population. As such, BS patients typically do not live past their 20’s. The BLM gene encodes the BLM helicase, a member of the highly conserved RecQ family of 3’ to 5’ DNA helicases. Most of our cellular understanding of BLM is through its role in DNA damage repair through the homologous …

Withaferin A And Immune Checkpoint Blocker Therapy For The Treatment Of Non-Small Cell Lung Cancer, Roukiah Khalil

USF Tampa Graduate Theses and Dissertations

Lung cancer is the first cause of cancer-related deaths in both men and women with an overall five-year survival rate of 28%. Although immune checkpoint blockers (ICBs) are currently FDA-approved for the treatment of non-small cell lung cancer (NSCLC), only 17-20% of patients achieve durable responses by the induction of immunologic memory. The lack of response in most patients can be attributed to the tumor-intrinsic or tumor-extrinsic immune resistance mechanisms. A biomarker of importance is the Programmed Death Ligand-1 (PD-L1), as higher PD-L1 expression is usually associated with a better response to ICBs. Although studies have attempted to combine ICBs …

Exploring Strain Variation And Bacteriophage Predation In The Gut Microbiome Of Ciona Robusta, Celine Grace F. Atkinson

USF Tampa Graduate Theses and Dissertations

Current microbiome studies have shown that the maintenance of homeostasis betweenmicrobial populations (e.g. bacteria, viruses) and the host immune system (e.g. innate immune molecules) is necessary for balancing health and disease outcomes within the host. These studies most often utilize vertebrate models; however, research in this field can benefit from diverse model systems that facilitate our ability to conduct experiments to identify phylogenically conserved rules influencing homeostasis in the gut of animals. The Dishaw has developed the use of a filter-feeding marine invertebrate chordate, Ciona robusta, to model such fundamental interactions[1]–[6]. While most biological diversity and functional contribution within microbiomes …

Effect Of Dual Inhibition Of Atypical Pkc Signaling And Pi3k/Akt Signaling On Cell Viability And Apoptosis In Clear Cell Renal Cell Carcinoma (Ccrcc)., Khandker M. Khalid

USF Tampa Graduate Theses and Dissertations

Renal Cell Carcinoma (RCC) is the most common type of kidney cancer (85%); 75% of the cases involve conventional clear cell RCC (ccRCC). The choice of treatments recommended for clear cell carcinoma and non-clear cell carcinoma include partial nephrectomy (Stage I), radical nephrectomy (Stages II and III), and chemotherapy (stage IV). Phosphatidylinositol-3-kinase (PI3K) inhibitors can be a viable candidate in the chemotherapy of ccRCC because the PI3K/Akt pathway is frequently activated in RCC. Hence, PI3K inhibitors like Alpelisib (BYL719) can be chosen as a treatment. In addition, aPKCs (PKC-ί and PKC ζ) are overexpressed in most cancer cells, and they …

Institutional And Individual Approaches To Change In Undergraduate Stem Education: Two Framework Analyses, Stephanie B. Feola

USF Tampa Graduate Theses and Dissertations

The overarching goal of this dissertation is to examine institutional change initiatives in STEM and to understand the impact of engaging with a specific change strategy on a biochemistry educator’s instructional practice. Institutional change initiatives involve executing an intentional strategy to influence teaching practices within a specific institution. This research investigates NSF-funded change initiatives at three public research universities that were focused on encouraging the adoption of evidenced-based instructional practices (EBIPs) by STEM faculty. As part of an effort to understand how the three institutions approached this task, framework analysis was performed using the initiative’s annual reports to NSF. Further …

Protein Folding Kinetics Analysis Using Fluorescence Spectroscopy, Dhanya Dhananjayan

USF Tampa Graduate Theses and Dissertations

The conformational changes that occur during the folding of a protein is an intensely researched area because of the impact that it has on human health and cellular functions. Protein stability is crucial in the context of protein misfolding and aggregation due to its implications on misfolding diseases such as amyloid fibril degenerative diseases (Alzheimer’s, Parkinson’s). By examining the kinetics of protein folding, we can gain valuable information about the folding mechanism and help us identify potential targets for many of the protein misfolding diseases.

In this study, we present the folding and unfolding kinetics of TEM-1 β-lactamase from Escherichia …

A Novel Role For Enos In Regulating Lymphatic Valve Development During Embryogenesis, Drishya Iyer

USF Tampa Graduate Theses and Dissertations

Lymphedema is a disease that occurs when lymph flow is impaired, resulting in tissue swelling, fibrosis, chronic inflammation and recurrent secondary infections. Lymphatic valves play a critical role in maintaining unidirectional lymph flow and evidence for valve defects have been reported in lymphedema patients. The lack of drugs that can correct lymphatic valve defects warrants a better understanding of the molecular regulators of lymphatic valve development and maintenance. Lymphatic valves first develop during embryogenesis in response to mechanotransduction signaling pathways triggered by oscillatory lymph flow. Since eNOS (gene name: Nos3) is a well characterized mechanotransduction signaling molecule in blood vessels, …

A Forward Genetic Screen Identifies Genes Involved In Gametocyte Development Of The Human Malaria Parasite Plasmodium Falciparum., Jyotsna Chawla

USF Tampa Graduate Theses and Dissertations

Transmission of the deadly malaria parasite Plasmodium falciparum from human to mosquito is achieved by specialized intraerythrocytic sexual forms called gametocytes. Circulating in the vertebrate host, relatively few intraerythrocytic gametocytes are picked up during a bloodmeal to continue sexual development in the mosquito vector. Human-to-vector transmission thus represents an infection bottleneck in the parasite's life cycle for therapeutic interventions to prevent malaria. Though the crucial regulatory mechanisms leading to gametocyte commitment have recently come to light, networks of genes that control sexual development remain to be elucidated. Here, we report a forward genetic approach to identify genes associated with gametocyte …

Apkcs Role In Neuroblastoma Cell Signaling Cascades And Implications Of Apkcs Inhibitors As Potential Therapeutics, Sloan Breedy

USF Tampa Graduate Theses and Dissertations

Neuroblastoma (NB) is a cancer that develops in the neuroblasts. It is the most common cancer in children under the age of 1 year, accounting for approximately 6% of all cancers. The prognosis of NB is linked to both age and degree of cell differentiation. This results in a range of survival rates for patients, with outcomes ranging from recurrence and mortality to high survival rates and tumor regression. Our previous work indicated that PKC-ι promotes cell proliferation in NB cells through the PKC-ι/Cdk7/Cdk2 cascade. We report on two atypical protein kinase inhibitors as potential therapeutic candidates against BE(2)-C and …

Dcaf14 Regulates Cdt2 To Promote Set8-Dependent Replication Fork Protection, Neysha Tirado-Class, Caitlin Hathaway, Anthony Nelligan, Huzefa Dungrawala

Molecular Biosciences Faculty Publications

DDB1- and CUL4-associated factors (DCAFs) CDT2 and DCAF14 are substrate receptors for Cullin4–RING E3 ubiquitin ligase (CRL4) complexes. CDT2 is responsible for PCNA-coupled proteolysis of substrates CDT1, p21, and SET8 during S-phase of cell cycle. DCAF14 functions at stalled replication forks to promote genome stability, but the mechanism is unknown. We find that DCAF14 mediates replication fork protection by regulating CRL4CDT2 activity. Absence of DCAF14 causes increased proteasomal degradation of CDT2 substrates. When forks are challenged with replication stress, increased CDT2 function causes stalled fork collapse and impairs fork recovery in DCAF14-deficient conditions. We further show that stalled fork protection …

Otud5 Limits Replication Fork Instability By Organizing Chromatin Remodelers, Angelo De Vivo, Hongseon Song, Yujin Lee, Neysha Tirado-Class, Anthony Sanchez, Sandy D. Westerheide, Huzefa Dungrawala, Younghoon Kee

Molecular Biosciences Faculty Publications

Proper regulation of replication fork progression is important for genomic maintenance. Subverting the transcription-induced conflicts is crucial in preserving the integrity of replication forks. Various chromatin remodelers, such as histone chaperone and histone deacetylases are known to modulate replication stress, but how these factors are organized or collaborate are not well understood. Here we found a new role of the OTUD5 deubiquitinase in limiting replication stress. We found that OTUD5 is recruited to replication forks, and its depletion causes replication fork stress. Through its C-terminal disordered tail, OTUD5 assembles a complex containing FACT, HDAC1 and HDAC2 at replication forks. A …

The Identification Of Two M20b Family Peptidases Required For Full Virulence In Staphylococcus Aureus, Nathanial James Torres, Devon Rizzo, Maria A. Reinberg, Mary-Elizabeth Jobson, Brendan C. Totzke, Jessica K. Jackson, Wenqi Yu, Lindsey Neil Shaw

Molecular Biosciences Faculty Publications

We have previously demonstrated that deletion of an intracellular leucine aminopeptidase results in attenuated virulence of S. aureus. Herein we explore the role of 10 other aminopeptidases in S. aureus pathogenesis. Using a human blood survival assay we identified mutations in two enzymes from the M20B family (PepT1 and PepT2) as having markedly decreased survival compared to the parent. We further reveal that pepT1, pepT2 and pepT1/2 mutant strains are impaired in their ability to resist phagocytosis by, and engender survival within, human macrophages. Using a co-infection model of murine sepsis, we demonstrate impairment of dissemination and survival …

Structural And Biochemical Characterization Of Epigenetic And Fusion Tyrosine Kinase Cancer Targets For Drug Development, Melissa Bikowitz

USF Tampa Graduate Theses and Dissertations

Cancer is a significant global health burden, as ~40% of the human population is diagnosed with cancer over a lifetime, half of which succumb to the disease. To develop novel compounds as potential cancer therapeutics, an in-depth structural and biochemical understanding of proteins involved in oncogenesis is key. This dissertation centers around the comprehensive structural and biochemical characterization of two classes of proteins critical for cancer cell survival: bromodomain-containing proteins (BRDs) and fusion tyrosine kinases (FTKs).In 2010, small molecule inhibitors targeting bromodomains (epigenetic reader proteins) became heavily popularized due to the druggability and potent anticancer effects of BET inhibitors. …

To Be Or Not To Be: A Tale Of Staphylococcal Gpsb, Lauren R. Hammond

USF Tampa Graduate Theses and Dissertations

There are two big drivers motivating studies into bacterial cell division. The first is a desire to understand life around us. One of the defining characteristics of life is the ability for a cell to grow and divide, and without in-depth knowledge of this process, we cannot truly understand the complexities that allow for life on this planet. The second motivator is to identify new drug targets in the ongoing fight against antimicrobial resistance. Many infectious organisms have become resistant to commonly used antibiotics, and the bacterial cell division machinery is a largely untapped essential process with many potential therapeutic …

Lord Of The Z-Rings: Uncovering The Role Of Mraz And Ftsl In Bacillus Subtilis Cell Division, Maria Louise White

USF Tampa Graduate Theses and Dissertations

Cell division is a complex and highly orchestrated process that requires careful coordination. The process of cell division in prokaryotes primarily occurs via binary fission, where one mother cell becomes two genetically identically and equally sized daughter cells. In most bacteria a key protein, FtsZ, forms a FtsZ ring (Z-ring) to mark the division site and recruit proteins involved in cytokinesis. Whilst much has been learned about the contents and assembly of the divisome in model organisms such as Escherichia coli and Bacillus subtilis factors governing the regulation of divisome are much more poorly understood. …

X-Linked Ubiquitin-Specific Peptidase 11 Increases Tauopathy Vulnerability In Women, Yan Yan

USF Tampa Graduate Theses and Dissertations

Women experience significantly higher tau burden and increased risk for Alzheimer’s disease (AD) than men, yet the underlying mechanism for this vulnerability has not been explained. Here, we demonstrate through in vitro and in vivo models, as well as human AD brain tissue, that X-linked ubiquitin specific peptidase 11 (USP11) augments pathological tau aggregation via tau deubiquitination initiated at lysine-281. Removal of ubiquitin provides access for enzymatic tau acetylation at lysines 281 and 274. USP11 escapes complete X-inactivation, and female mice and people both exhibit higher USP11 levels than males. Genetic elimination of usp11 in a tauopathy mouse model preferentially …

Identification Of Secondary Structural Elements Contained Within The Intrinsically Disordered N-Terminal Tail Of The Bloom’S Syndrome Helicase., Vivek Somasundaram

USF Tampa Graduate Theses and Dissertations

The Bloom’s Syndrome Helicase (BLM) is one of five human RecQ helicases and is necessary for maintenance of genome stability. Whilst a crystal structure exists for the C-terminal domain of BLM, very limited structural knowledge is known about the intrinsically disordered N-terminal tail. This lack of insight exists, despite the fact that the N-terminus of BLM is essential for the overall biological activity of BLM. Here we provide an Nuclear Magnetic Resonance spectroscopy based approach that we used to identify two distinct ⍺-helices contained within the first 100 residues of BLM. In addition, we propose a mutagenesis-based approach involving rationally …

The Role Of Protein Palmitoylation In Two Disorders; X-Linked Intellectual Disability And Covid-19, Ahmed A. Ramadan

USF Tampa Graduate Theses and Dissertations

The spike proteins of enveloped viruses are transmembrane glycoproteins that typically undergo post-translational attachment of palmitate on cysteine residues on the cytoplasmic facing tail of the protein. The role of spike protein palmitoylation in virus biogenesis and infectivity is being actively studied as a potential target of novel antivirals. Here, we report that palmitoylation of the first five cysteine residues of the C-terminal cysteine-rich domain of the SARS-CoV-2 S protein are indispensable for infection, and palmitoylation-deficient spike mutants are defective in membrane fusion. The DHHC9 palmitoyltransferase interacts with and palmitoylates the spike protein in the ER and Golgi, and knockdown …

Regulation Of The Heat Shock Response Via Lysine Acetyltransferase Cbp-1 And In Neurodegenerative Disease In Caenorhabditis Elegans, Lindsey N. Barrett

USF Tampa Graduate Theses and Dissertations

The decline of proteostasis is a hallmark of aging that is, in part, affected by the dysregulation of the heat shock response (HSR), a highly conserved cellular response to proteotoxic stress in the cell. The heat shock transcription factor HSF-1 is well-studied as a key regulator of proteostasis, but mechanisms that could be used to modulate HSF-1 function to enhance proteostasis during aging are largely unknown. In this study, we examined lysine acetyltransferase regulation of the HSR and HSF-1 in C. elegans. We performed an RNA interference screen of lysine acetyltransferases and examined mRNA expression of the heat-shock inducible gene …

A Protein-Based Therapeutic Combination For The Treatment Of Hard-To-Heal Wounds, Graham L. Strauss

USF Tampa Graduate Theses and Dissertations

Chronic wounds present many clinical challenges in relation to the successful treatment and closure of the damaged tissue. Most current treatment methods focused on one or two aspects to drive wound closure, while most chronic wounds are multifactorial environments with many of those dependencies relying on the termination of one another to effectively gain tissue construction, closure, and full skin thickness and composition. Natural wound healing processes allude to potential biologics that can impede the chronic breakdown of tissue, while restoring deposition of new tissue, and effectively leading to a healed wound. Proteases secreted by the body’s immune system lay …

Nanophotonics And Nanomaterials For Microbial Inactivation, Sharad Ambardar

USF Tampa Graduate Theses and Dissertations

The study of light-matter interaction at nanoscale, also termed as nanophotonics, has gained vast attention due to its multidisciplinary application in the field of chemical engineering for the synthesis of nanomaterials, in the field of physics to study non-linear optical processes and optical phenomena in nanocavities and in the field of biology, biomedicine to study and develop novel optical nanoprobes for diagnostics, nanobiosensing and near-field imaging.

We studied UV-irradiation-based inactivation of SARS-CoV-2 and other respiratory viruses. In this work, we fabricated a device comprising a pulsed nanosecond 266 nm UV laser coupled to an integrating cavity (LIC), composed of a …

Ceramide-1-Phosphate: A Novel Regulator Of Golgi Fragmentation, Golgi-Er Vesicle Trafficking, And Anaplasma Phagocytophilum Pathogenesis, Anika Nayar Ali

USF Tampa Graduate Theses and Dissertations

Anaplasma phagocytophilum, the etiologic agent of human granulocytic anaplasmosis (HGA), is a tick transmitted obligate intracellular bacterium that infects granulocytes, bone marrow progenitor cells and endothelial cells. HGA exhibits symptoms of febrile illness including fever, chills, headache, malaise, leukopenia and elevated liver enzymes which are treatable by antibiotics. However, elderly and immunocompromised patients are at a greater risk of developing fatal complications. Inside the host cell A.phagocytophilum resides in host cell derived vacuole called A.phagocytophilum occupied vacuole (ApV) where it undergoes its biphasic lifecycle. Being an intracellular pathogen, A.phagocytophilum relies heavily on nutrient acquisition from host cell and to obtain …

Glucose Homeostasis In Human Diabetic Adipocytes: Role Of Glp1 In Sortilin Alternative Splicing, Ashley Lui

USF Tampa Graduate Theses and Dissertations

Type 2 diabetes mellitus (T2DM) is a chronic and progressive metabolic disease defined by systemic insulin resistance. The inability of cells to respond to insulin and take up glucose results in elevated blood sugar that is detrimental to the overall health of patients. There is no cure for T2DM. Identification of new targets to alleviate hyperglycemia are crucial for treatment and prevention of metabolic diseases. Adipocytes play a central role in glycemic regulation by insulin stimulated glucose uptake, storage of excess nutrients, and secretion of adipokines. Major glucose transporter-4 (Glut4) is the main transporter responsible for postprandial clearance of glucose …

Development Of Enhanced Algae Strains And Sustainable Cultivation Processes For Production Of Algal Lipids For Biofuels And Bioproducts, Enlin Lo

USF Tampa Graduate Theses and Dissertations

The establishment of an algae industry is crucial for addressing global biofuel and bioproduct demand that meets the Sustainable Development Goals (SDG) worldwide. Photosynthetic microalgae are excellent sources for food, fiber, fuel, feed, and fertilizer, which are the 5Fs of the SDG. However, at present, algae-based materials are not cost-competitive or sufficiently sustainable. Improved productivity, lower cultivation cost, and reduced use of resources are required to transition from lab to industry, necessitating the development of superior strains that have high productivity and can tolerate environmental stress, such as temperature and salinity, so they can be cultivated at large scale outdoors …

Defining The Role Of Oxidized Mitochondrial Dna In Myelodysplastic Syndromes, Grace Anne Ward

USF Tampa Graduate Theses and Dissertations

Myelodysplastic Syndromes (MDS) are heterogeneous bone marrow (BM) failure malignancies characterized by constitutive innate immune activation, NLRP3 inflammasome (IFM) driven pyroptotic cell death, and the induction of interferon-stimulated genes (ISG). MDS often diagnostically resembles other hematologic disorders, as such, additional tools are needed for the discrimination from overlapping disorders. We observed that oxidized mitochondrial DNA (ox-mtDNA) is released upon cytolysis. We hypothesize that levels of ox-mtDNA are high in MDS, allowing us to use it as a diagnostic biomarker; and that cell free ox-mtDNA is contributing to feedforward BM failure.

ROC/AUC analysis demonstrated that ox-mtDNA is a sensitive and specific …

The Role Of Eicosanoid Metabolism In Mammalian Wound Healing And Inflammation, Kenneth D. Maus

USF Tampa Graduate Theses and Dissertations

Inflammatory wounds, both chronic and acute, lead to increased morbidity and mortality rates, especially in the elderly population. The annual healthcare cost for chronic wound care alone is over $39B in the US and the demographic of susceptible patients is steadily increasing due to an aging population and lifestyle-related diseases (e.g., hyperlipidemia, obesity, and type 2 diabetes). In fact, many chronic wounds currently have a worse 5-year outlook than certain types of cancers. This shows the need for expediting the wound healing process in such a way that compresses inflammatory signaling and encourages wound resolution without sacrificing pathogen removal and …

Impact Of Arginine Metabolism And Sensing In Mouse Models Of Alzheimer’S Disease, Chao Ma

USF Tampa Graduate Theses and Dissertations

Alzheimer’s disease (AD) remains the most common neurodegenerative disease in the central nervous system (CNS), with amyloidosis and tauopathy as their two main hallmarks. Typical AD pathologies include cerebral plaques deposited by amyloid-β, neurofibrillary tangles aggregated by tau, and neuroinflammation caused by activated brain myeloid cells. A critical theme is centered on impaired brain metabolism. Emerging evidence showed that impaired arginine metabolism was a novel biomarker pathway for AD. The manipulation of arginine metabolism by a critical enzyme arginase 1 (ARG1) in neurons indicated therapeutic benefits in alleviating tau pathology. Balanced cellular proteostasis was governed by the mechanistic target of …