Cell Biology Commons^™

A Novel Role Of Hrr25 In Cell Wall Integrity Maintenance And Functional Analysis Of Hrr25 Domains, Amita Bhattarai

LSU New Orleans Theses and Dissertations

Hrr25 is a highly conserved serine/threonine protein kinase with diverse functions and it localizes to a number of intracellular sites. Hrr25 possesses an N-terminal kinase domain, a middle region, and a C-terminal proline/glutamine rich domain. In this thesis, we systematically characterized the roles of these three domains of Hrr25 on cell growth, cell morphology, and its cellular localizations. Additionally, we identified a novel target of Hrr25, Pin4. We show that Hrr25-dependent phosphorylation of Pin4 is required for cell wall integrity maintenance. We found that that Hrr25 and Pin4 physically interact in vivo and that the C-terminal domain of Hrr25 is …

Natural Autoantibodies: Origin, Function And Utility For Diagnosis Of Disease, Abhirup Sarkar

Graduate School of Biomedical Sciences Theses and Dissertations

Autoantibodies (aAbs) by the simplest definitions have been described as antibodies against self-antigens and were exclusively associated with autoimmune diseases. Eventually, studies demonstrated that they are abundant in the blood of all human sera, regardless of age, gender, or the presence or absence of disease, and were thus named as ‘natural autoantibodies’. The underlying reason for their ubiquity has remained elusive, but we have hypothesized that they are responsible for clearing blood-borne cell and tissue debris generated under conditions of health and disease. To test this, we chose to use two widely different disease model systems, namely neurodegenerative diseases and …

Sensory Primary Cilium Is A Distinct Signaling Compartment, Rinzhin Tshering Sherpa

Pharmaceutical Sciences (PhD) Dissertations

The primary cilium is a solitary cellular organelle that protrudes from the apical cell membrane. Findings on cilia-dependent mechanosenstation have shown that the primary cilium acts as a transducer of fluid-shear stress into intracellular signaling. Over recent years, studies in primary cilia have intensified after determining a causal relationship between dysfunctional primary cilia and cystic diseases. Along with its mechanosensory function, the primary cilium houses a variety of receptors, ion channels and transporter proteins. Studies in cilia biology have shown that primary cilia are coordinators of signaling pathways such as Hedgehog (Hh), Wnt, and platelet-derived growth factor (PDGF) pathways during …

The Influence Of Mir-322 On Skeletal Muscle Differentiation, Miles Alexander Soyer

Legacy Theses & Dissertations (2009 - 2024)

Skeletal muscle plays a crucial role in coordinating voluntary movement and accounts for nearly 50% of total body mass. Dysregulation in skeletal muscle development is known to cause muscle degenerative diseases including the devastating Duchenne Muscular Dystrophy (DMD). The majority of the biological studies investigating muscle development were based on myogenic transcription factors and signaling molecules including: Pax7, Myf5, MyoD, WNT, TGF-β and BMP. After the discovery of non-coding RNAs including microRNAs, it was postulated that these molecules could regulate gene expression and thus affect differentiation and development. MicroRNAs are small non-coding RNAs (~17-25 nucleotides) that regulate gene expression negatively …

Protein Structure Analysis, Agnieszka Szarecka, Chris Dobson

Peer Reviewed Articles

We describe a series of engaging exercises in which students emulate the process that researchers use to efficiently develop new pharmaceutical drugs, that of rational drug design. The activities are taken from a three- to four-hour workshop regularly conducted with first-year college students and presented here to take place over three to four class periods. Although targeted at college students, these activities may be appropriate at the high school level as well, particularly in an AP Biology course. The exercises introduce students to the topics of bioinformatics and computer modeling, in the context of rational drug design, using free online …

The Functional And Structural Analysis Of Drosophila Robo2 In Axon Guidance, Lafreda Janae Howard

Graduate Theses and Dissertations

In animals with complex nervous systems such as mammals and insects, signaling pathways are responsible for guiding axons to their appropriate synaptic targets. Importantly, when this process is not successful during the development of an organism, outcomes include catastrophes such as human neurological diseases and disorders. It is vital to determine the underlying causes of such diseases by understanding the development of the nervous system. There are many pathways that have been identified to play a role in this, however, we lack an understanding of how these pathways can promote such diverse outcomes in different populations of neurons. These pathways …

Assessing The Efficacy Of Seedling Planting As A Forest Restoration Technique In Temperate Hardwood Forests Impacted By Invasive Species, Michaela J. Woods, Meredith Cobb, Katie Hickle

Biology Faculty Publications

The emerald ash borer (Agrilus planipennis Fairmaire; EAB) is an invasive insect that causes mortality of trees in the genus Fraxinus, creating canopy gaps that may facilitate invasion by exotic plants. Planting native tree seedlings under EAB-infested Fraxinus may accelerate succession and preclude invasive plant expansion; however, the effectiveness of this approach has not been experimentally tested. We assessed understory seedling planting of Quercus rubra, Carya laciniosa, and Juglans cinerea in EAB-infested forests, where the invasive shrub Lonicera maackii (Amur honeysuckle) was removed. We tested whether the use of plastic tree shelters (“tree tubes”) or planting season (fall versus spring) …

Bioengineering Extracellular Matrix Scaffolds For Volumetric Muscle Loss, Kevin Roberts

Graduate Theses and Dissertations

Volumetric muscle loss overwhelms skeletal muscle’s ordinarily capable regenerative machinery, resulting in fibrosis and severe functional deficits which have defied clinical repair strategies. My work spans the design and preclinical evaluation of implants intended to drive the cell community of injured muscle toward a regenerative state, as well as the development of an understanding of the molecular responses of this cell community to biomaterial interventions. I demonstrate a new class of biomaterial by leveraging the productive capacity of sacrificial hollow fiber membrane cell culture; I show specifically that unique threads of whole extracellular matrix can be isolated by solvent degradation …

The Functional Conservation Of Frazzled In Insects, Benjamin Wadsworth

Graduate Theses and Dissertations

Axons in the developing embryo receive and react to signals that direct their growth to reach target tissues at specified locations. The signal pathways that direct midline crossing of axons during embryonic development have been comprehensively examined in the past years using the Drosophila ventral nerve cord or the spinal cord as a model system. A number of these signaling mechanisms are conserved, however disparities have been found between species in general strategy or the molecular signals controlling the response of axons to guidance cues.

The Netrin-Frazzled pathway has been shown to aid in midline crossing of axons in the …

Ipsc Based Gene Correction And Disease Model Of A New Class Of Lgmd Due To Poglut1 Mutation, Jose Ortiz-Vitali

Dissertations and Theses (Open Access)

Recently, a novel class of muscular dystrophy has been discovered in a family due to autosomal recessive missense mutation in POGLUT1. Mutation of this enzyme leads to decreased O-glucosyltransferase activity and impaired Notch signaling, the pathways important for skeletal muscle stem cell (satellite cells) quiescence and activation. We hypothesize that reduced POGLUT1 activity and impaired Notch signaling is causative of this limb girdle muscular dystrophy through dysfunction of muscle stem cells and myogenic progenitors.

To test this, we have used iPSCs for disease modeling and rescue experiments. Using a CRISPR based gene targeting method, we aimed to correct the point …

The Distinct Expressions Of Integrins Αdβ2 And Αmβ2 Differently Regulate Macrophage Migration In 3d Matrix In Vitro And In Tissue During Inflammation, Kui Cui

Electronic Theses and Dissertations

Chronic inflammation is an essential mechanism during the development of cardiovascular and metabolic diseases. The outcome of diseases depends on the balance between the migration and accumulation of macrophages in damaged tissues. Macrophage motility is highly regulated by adhesive receptors, integrins. Namely, intermediate expression of integrin supports macrophage migration, while a high integrin density inhibits it. Our studies are focused on evaluation of the contribution of related integrins α_Dβ₂ and α_Mβ₂ to macrophage migration and development of chronic inflammation.

We found that integrin α_Dβ₂ is upregulated on M1-macrophages in vitro and …

The Gsk-3Β-Fbxl21 Axis Regulates Tcap Via Ubiquitin-Mediated Proteasomal Pathway In The Cytoplasm, Jiah Yang

Dissertations and Theses (Open Access)

Protein turnover is one of the most essential mechanisms controlling circadian rhythms. F-Box and Leucine Rich Repeat Protein21 (FBXL21) is a circadian E3 ligase which shows oscillatory mRNA transcripts and protein levels. It was previously found to perform subcellular compartment-specific E3 ligase activities targeting the core clock proteins CRYPTOCHROME(CRY)1/2. Here we identified a new sarcomeric target substrate, Telethonin(TCAP), which also shows circadian oscillation in its mRNA transcript and protein expression and, importantly, interaction with FBXL21 in an anti-phasic manner. Via computational and pharmacological tests, we identified Glycogen Synthase Kinase-3β(GSK-3β) as a regulator of FBXL21. Biochemical and molecular characterizations demonstrated that …

Modeling Cancer Using Li-Fraumeni Syndrome Patient-Derived Induced Pluripotent Stem Cells, Ruoji Zhou

Dissertations and Theses (Open Access)

Li-Fraumeni syndrome (LFS) is an autosomal dominant disease caused by germline mutations in the gene TP53, which predispose individuals to a wide range of malignancies, including osteosarcoma and breast cancer. In the previous study, our group developed a novel disease model platform by reprograming LFS patients' fibroblasts to induced pluripotent stem cells (iPSCs), and further differentiate these iPSCs into mesenchymal stem cells (MSCs) then to osteoblasts (OBs), the cells from which osteosarcomas originate. Interestingly, LFS iPSC-derived osteoblasts recapitulated the osteosarcoma phenotype, creating “a bone tumor in a dish”. This “tumor in a dish” platform proved that LFS is an …

Deubiquitinating Enzymes Promote Cancer Progression And Metastasis Via Regulating Protein Stability, Zhenna Xiao

Dissertations and Theses (Open Access)

Deubiquitinating enzymes (DUBs, also called deubiquitinases) are enzymes that remove monoubiquitin or polyubiquitin chains from target proteins. DUBs have critical roles in cell homeostasis and signal transduction, as they regulate protein degradation, subcellular localization, and protein-protein interaction. Deregulation of DUBs contributes substantially to tumor formation and progression, and therefore targeting DUBs may be a promising cancer therapy strategy. My dissertation focuses on identifying the DUBs of EZH2 and SNAI1, two proteins critical for cancer progression and metastasis, and establishing these DUBs as promising anti-cancer targets.

EZH2, the catalytic component of the PRC2 complex, silences gene transcription by histone methylation. High …

Emergence Of Oxacillin Resistance In Stealth Methicillin-Resistant Staphylococcus Aureus Due To Meca Sequence Instability, Richard V. Goering, Erin A. Swartzendriber, Anne E. Obradovich, Isabella A. Tickler, Fred C. Tenover

Biology Faculty Publications

Staphylococcus aureus strains that possess a mecA gene but are phenotypically susceptible to oxacillin and cefoxitin (OS-MRSA) have been recognized for over a decade and are a challenge for diagnostic laboratories. The mechanisms underlying the discrepancy vary from isolate to isolate. We characterized seven OS-MRSA clinical isolates of six different spa types from six different states by whole-genome sequencing to identify the nucleotide sequence changes leading to the OS-MRSA phenotype. The results demonstrated that oxacillin susceptibility was associated with mutations in regions of nucleotide repeats within mecA. Subinhibitory antibiotic exposure selected for secondary mecA mutations that restored oxacillin resistance. …

The ‘Law Of Environmental Dependence’ - Biology And Ethics In The Work Of Ernest Everett Just: + Found – Some 251 Mostly Typed Pages, Theodore Walker

Perkins Faculty Research and Special Events

Abstract-

“The Origin of Man’s Ethical Behavior” (circa October 1941) by Ernest Everett Just and Hedwig A. Schnetzler Just - is an unpublished book manuscript about the biological origins and evolution of ethical behavior, and about “the law of environmental dependence.” Missing since Just’s death in October 1941, it was found and identified in May 2018 among the collected papers of Ernest Everett Just preserved at the Howard University Moorland-Spingarn Research Center in Washington, DC. In addition to the 1996 US postage with the caption “Ernest E. Just, Biologist,” we now have reason to add two new postage stamps with …

Role Of Host Cell Β-Catenin During Toxoplasma Gondii Infection, Cameron H. Ranken

Biology ETDs

The microbial pathogen Toxoplasma gondii is an intracellular protozoan that actively invades host cells and simultaneously creates a specialized parasitophorous vacuole within which the parasite lives and replicates. The parasite molecular machinery that drives establishment of the intracellular niche is relatively well known. However, it is now emerging that Toxoplasma exploits less well-understood host cell components to enable successful infection. Here, we examined the role of host Wnt/β-catenin during T. gondii infection. Using human fibroblasts and a mouse dendritic cell line, we found that infection with Toxoplasma stimulated both upregulation and nuclear localization of β-catenin. Using a transwell experimental approach, …

Targeting Pten For Therapy In Cancer And Ptenopathies, Emily Palumbo

USF Tampa Graduate Theses and Dissertations

PTEN, a dual protein and lipid phosphatase, regulates a myriad of cellular functions including PI3K pathway signaling, cell migration, proliferation, invasion and apoptosis. PTEN mutations often lead to multiple malignancies, including prostate, breast, endometrial, skin and brain cancers, associated with hyperactive PI3K signaling. PTEN mutations have also been associated with a variety of other diseases, classified as PTEN Hamartoma Tumor Syndromes (PHTS). In addition, compromised function or reduced expression of PTEN due to non-genomic mechanisms are associated with many types of hyperproliferative diseases, such as restenosis and neoplastic diseases, including melanoma, lung, breast, prostate and colon cancers. Although PI3K pathway …

Characterization Of Human Dutpase, Shawna Marie Rotoli

Graduate School of Biomedical Sciences Theses and Dissertations

Deoxyuridine nucleotidyl transferase (dUTPase) is an enzyme found in all organisms that have thymine as a component of DNA. It catalyzes the hydrolysis of dUTP to dUMP and pyrophosphate thus precluding the buildup of dUTP pools as well as providing the substrate, dUMP, for the de novo synthesis of thymidylate. In Homo sapiens, there are four isoforms: mitochondrial (mDut), nuclear (nDut), variant 3 and variant 4. This work is largely focused on nDut. Using structural and MS analyses of recombinant dUTPase constructs, an intermolecular disulfide bridge between cysteine-3 of each nDut monomer was discovered. It was found that these two …

Development Of A Prolyl Endopeptidase Expression System In Lactobacillus Reuteri To Reduce The Clinical Manifestation Of Celiac Disease, Kara Lynn Jew

Master's Theses

Celiac Disease (CD) is an autoimmune disorder that emerges due to the ingestion of gluten, a protein found in a variety of common grains such as wheat, rye, and barley. Approximately 1 in 100 individuals in the US suffer from CD, making it the most commonly diagnosed gastrointestinal disorder (Ciclitira et. al., 2005). These proline-rich gluten peptides are resistant to proteolysis and accumulate in the duodenum of the small intestine. Once in the duodenum, these peptides illicit an autoimmune response resulting in villous atrophy. Current treatment for CD requires a rigorous adherence to a gluten-free diet. Nevertheless, gluten-containing grains are …