Life Sciences Commons^™

Photophysical And Optical Properties Of Semiconducting Polymer Nanoparticles Prepared From Hyaluronic Acid And Polysorbate 80, Adam Langlois, Gage T. Mason, Michael H.L. Nguyen, Mehdi Rezapour, Paul Ludovic Karsenti, Drew Marquardt, Simon Rondeau-Gagné

Chemistry and Biochemistry Publications

Copyright © 2019 American Chemical Society. A nanoprecipitation procedure was utilized to prepare novel diketopyrrolopyrrole-based semiconducting polymer nanoparticles (SPNs) with hyaluronic acid (HA) and polysorbate 80. The nanoprecipitation led to the formation of spherical nanoparticles with average diameters ranging from 100 to 200 nm, and a careful control over the structure of the parent conjugated polymers was performed to probe the influence of π-conjugation on the final photophysical and thermal stability of the resulting SPNs. Upon generation of a series of novel SPNs, the optical and photophysical properties of the new nanomaterials were probed in solution using various techniques including …

Amyloid Proteins And Fibrils Stability, Farbod Mahmoudinobar

Dissertations

Compared to globular proteins that have a stable native structure, intrinsically disordered peptides (IDP) sample an ensemble of structures without folding into a native conformation.One example of IDP is the amyloid-beta(Abeta) protein which is the main constituent of senile plaques in the brain of Alzheimer's patients.Understanding the process by which IDPs undergo structural changes to form oligomers that eventually aggregate into senile plaques/amyloid fibrils may significantly advance the development of novel therapeutic methods to treat neurodegenerative diseases, for which there is no cure to date. This dissertation has two main objectives. The first one is to investigate and identify structural …

Architecture Of The Chromatin Remodeler Rsc And Insights Into Its Nucleosome Engagement., Avinash B Patel, Camille M Moore, Basil J Greber, Jie Luo, Stefan A Zukin, Jeff Ranish, Eva Nogales

Articles, Abstracts, and Reports

Eukaryotic DNA is packaged into nucleosome arrays, which are repositioned by chromatin remodeling complexes to control DNA accessibility. The

Robust Cullin-Ring Ligase Function Is Established By A Multiplicity Of Poly-Ubiquitylation Pathways, Spencer Hill, Kurt Reichermeier, Daniel C. Scott, Lorena Samentar, Jasmin Coulombe-Huntington, Luisa Izzi, Xiaojing Tang, Rebeca Ibarra, Thierry Bertomeu, Annie Moridian, Michael J. Sweredoski, Nora Caberoy, Brenda A. Schulman, Frank Sicheri, Mike Tyers, Gary Kleiger

Life Sciences Faculty Research

The cullin-RING ligases (CRLs) form the major family of E3 ubiquitin ligases. The prototypic CRLs in yeast, called SCF enzymes, employ a single E2 enzyme, Cdc34, to build poly-ubiquitin chains required for degradation. In contrast, six different human E2 and E3 enzyme activities, including Cdc34 orthologs UBE2R1 and UBE2R2, appear to mediate SCF-catalyzed substrate polyubiquitylation in vitro. The combinatorial interplay of these enzymes raises questions about genetic buffering of SCFs in human cells and challenges the dogma that E3s alone determine substrate specificity. To enable the quantitative comparisons of SCF-dependent ubiquitylation reactions with physiological enzyme concentrations, mass spectrometry was employed …

Peroxiredoxin 6 And Inflammation In Alzheimer's Disease, Jared Ferrell-Penniman

Biological Sciences Theses and Dissertations

Alzheimer’s disease (AD) is known for its debilitating symptoms and poor prognosis. However, despite intense research into neurodegenerative diseases, there are few therapies targeted at the underlying mechanisms of the disease. Oxidative stress (OS) and inflammation are cellular phenomena thought to be key to the progression of the disease. Critically, peroxiredoxin 6 (Prx6), an antioxidant protein with multiple functions, has been identified from mammalian studies as a potential regulator of both OS and inflammation that may have a specific effect on AD. This project seeks to elucidate the role of Prx6 in AD as well as the underlying mechanisms. Drosophila …

Nanomaterials For Biosensing Lipopolysaccharide, Palak Sondhi, Helal Maruf, Keith Stine

Chemistry & Biochemistry Faculty Works

Lipopolysaccharides (LPS) are endotoxins, hazardous and toxic inflammatory stimulators released from the outer membrane of Gram-negative bacteria, and are the major cause of septic shock giving rise to millions of fatal illnesses worldwide. There is an urgent need to identify and detect these molecules selectively and rapidly. Pathogen detection has been done by traditional as well as biosensor-based methods. Nanomaterial based biosensors can assist in achieving these goals and have tremendous potential. The biosensing techniques developed are low-cost, easy to operate, and give a fast response. Due to extremely small size, large surface area, and scope for surface modification, nanomaterials …

Transcription Regulation Of Human Il1b Gene In Monocytes And Lymphoid Cd4 T Cells, Sree H. Pulugulla

Electronic Theses and Dissertations

Cytokines are key regulators of the inflammatory response and play an important role in facilitating intercellular communication between various immune cell types. Interleukin‑1β (IL‑1β) is a potent pro-inflammatory cytokine that is required for robust initiation of innate immune response and subsequent development of adaptive immunity. IL-1β is first synthesized as an inactive cytoplasmic, non‑glycosylated, precursor molecule (proIL‑1β) by monocytes and macrophages in response to invading pathogenic microbes. The activation of caspase‑1 by inflammasomes cleaves proIL-1β into mature biologically active IL-1β that is released from cells via a non-classical, endoplasmic reticulum‑independent secretory pathway directly from the cytoplasm via Gasdermin D membrane …

State-Dependent Mapping Of Glyr-Cholesterol Interactions By Coupling Crosslinking With Mass Spectrometry, Nicholas Ferraro

Electronic Theses and Dissertations

The glycine receptor (GlyR) belongs to a superfamily of pentameric ligand-gated ion channels (pLGICs) that mediate fast neurotransmission. GlyR typically modulates inhibitory transmission by antagonizing membrane depolarization through anion influx. Allosteric interactions between the receptor and its lipid surroundings affect receptor function, and cholesterol is essential for pLGIC activity. Human α1 GlyR was purified from baculovirus infected insect cells and reconstituted in unilamellar vesicles at cholesterol: lipid ratios below and above the cholesterol activity threshold with aliquots of azi-cholesterol. State-dependent crosslinking studies of receptors primarily in its resting (no glycine), desensitized (10mM glycine) and open (F207A/A288G, 30nM ivermectin) states were …

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Engineering Hyaluronic Acid For Biomedical Applications, Deep S. Bhattacharya

Theses & Dissertations

This work presents research using the naturally available non- sulfated carbohydrate glycosaminoglycan hyaluronic acid (HA) for the synthesis of different chemical derivatives of HA for evaluation of binding kinetics with CD44 and P- selectin proteins for applications in fluorescence image-guided surgery. Chemical derivatives of HA such as deacetylated HA (deHA), sulfated HA (sHA), and deacetylated and sulfated HA (s-deHA) were synthesized by modulating sulfating and deacetylating reagents to alter binding specificities to CD44. Modified HA derivatives and CD44 biophysical interactions were assessed by fluorescence polarization. In silico techniques were also used to determine binding using molecular docking and MM-PBSA approaches. …

Brca1 & Ctdp1 Brct Domainomics In The Dna Damage Response, Kimiko L. Krieger

Theses & Dissertations

Genomic instability is one of the enabling characteristics of cancer. DNA damage response pathways are important for genomic integrity and cell cycle progression. Defects in DNA damage repair can often lead to cell cycle arrest, cell death, or tumorigenesis. The activation of the DNA damage response includes tightly regulated signaling cascades that involve kinase phosphorylation and modular domains that scaffold phosphorylated motifs to coordinate recruitment of DNA repair proteins. Modular domains are conserved tertiary structures of a protein that can fold, function, and evolve independently from an intact protein. One of the most common modular domains involved in DNA damage …

Cholesterol Biosynthesis In The Nervous System With An Emphasis On Desmosterolosis, Luke Allen

Theses & Dissertations

Cholesterol biosynthesis is integral to proper neurodevelopment due to the reliance on de novo synthesis of cholesterol in the brain. Disruptions in this process have devastating outcomes for human life characterized by several phenotypic manifestations concomitant with developmental delay. The cholesterol biosynthesis disorder desmosterolosis is an extremely rare disorder with a severe clinical phenotype, however, the models used to study this disease are not well characterized. In addition to genetic disruptions in cholesterol biosynthesis, pharmacological perturbation is an understudied side effect of many commonly prescribed drugs. Here we present a characterization of the sterol profile of the mouse model of …

Defining The Role Of Tyrosine Phosphorylation In The Regulation Of Connexin43 In Cardiac Diseases, Li Zheng

Theses & Dissertations

Connexins are integral membrane proteins that oligomerize to form gap junction channels. Ions and small molecules diffuse intercellularly through these channels, allowing individual cellular events to synchronize into the functional response of an entire organ. Gap junction channels composed of Connexin43 (Cx43) mediate electrical coupling and impulse propagation in the normal working myocardium. In the failing heart, Cx43 remodeling (decreased expression, altered phosphorylation state, loss at intercalated discs, and increased presence at lateral membranes) contributes to rhythm disturbances and contractile dysfunction. While there is considerable information regarding key interactions of Cx43 in the regulation of gap junction channels, unfortunately, the …

Functional Implications Of Nlrp1 Variants For Autoimmune Disease, Laura J. Westhoff

Undergraduate Honors Theses

NLRP1 is a protein-coding human gene that plays a crucial role in the NLRP1 inflammasome. Variants to the NLRP1 gene have been associated with autoimmune and autoinflammatory diseases. We examined the effects of polymorphisms at two SNPs on cytokine levels and NLRP1 gene expression in 50 human volunteers without diagnosed autoimmune disease. NLRP1 was genotyped at SNPs rs2670660 and rs12150220 and individuals who were homozygous at one or more SNP were selected for further analysis. Serum IL-18 and IL-1β levels were quantified using ELISA. NLRP1 gene expression was measured using real-time PCR. A strong linkage was found between genotypes of …

Ecdysoneless, A Novel Regulator Of Ca2+ Homeostasis And Metabolism, Aniruddha Sarkar

Theses & Dissertations

The hallmarks of cancer include sustained proliferation and survival in the face of cellular stresses imposed by the oncogenic drive, as well as metabolic rewiring for tumor growth under adverse nutritional conditions. Adaptive alterations in key biochemical networks that underlie metabolic rewiring represent potential opportunities to develop new therapeutic strategies against cancer.

My thesis focuses on mammalian Ecdysoneless (ECD), a conserved homolog of the fly Ecdysoneless gene product, which engages fundamental cell biological processes of ER stress, Ca²⁺ signaling and metabolism to help sustain the oncogenic drive in tumor cells. Recent studies from our laboratory provide a clear evidence …

The Role Of Reactive Oxygen Species In Regulating Macrophage And Fibroblast Activation Within The Breast Cancer Tumor Microenvironment, Brandon J. Griess

Theses & Dissertations

The tumor microenvironment (TME) is a key determining factor in breast cancer, especially the more aggressive subtype triple negative breast cancer (TNBC). The activated fibroblasts and macrophages within the TME have many tumor promoting functions. Therefore, targeting their activation presents a novel therapeutic approach in TNBC. My work studied the role of reactive oxygen species (ROS) during fibroblast and macrophage activation in breast cancer.

My studies showed that expression of the secreted antioxidant enzyme, EcSOD, is silenced in breast cancer samples, in part, via increased promoter methylation. The re-expression of EcSOD inhibited c-Met activation in the TNBC cell line, MDA-MB231. …

Delivery Of Small Molecule And Rna Using Synthetic Polymeric Micelles And Multifunctional Exosomes For The Treatment Of Type 1 Diabetes, Yang Peng

Theses & Dissertations

Type 1 diabetes is one of the most challenging chronic autoimmune diseases. The destruction and dysfunction of insulin-secreting β cells are the results of inflammatory infiltration and the synergistic effect of multiple immune cells. The aim of this dissertation is to develop novel and reliable therapeutic approaches to advance the treatment of T1D: including chemical modification of a broad-spectrum immunosuppressant, co-application of small molecule based immune intervention and siRNA based β cell preservative therapy, and administration of a PI3K-δ/γ dual inhibitor to specifically target immune cells, utilizing synthetic polymeric micelles or natural produced multi-functional exosomes derived from human bone marrow …

Hdac1 Is A Required Cofactor Of Cbfβ-Smmhc And A Therapeutic Target In Inversion 16 Acute Myeloid Leukemia, Lisa E. Richter

Theses & Dissertations

Acute myeloid leukemia (AML) is a neoplastic disease characterized by the uncontrolled proliferation and accumulation of immature myeloid cells. A common mutation in AML is the inversion of chromosome 16 [inv(16)], which generates a fusion between the genes for core binding factor beta (CBFB) and smooth muscle myosin heavy chain (MYH11), forming the oncogene CBFB-MYH11. The expressed protein, CBFβ-SMMHC, forms a heterodimer with the key hematopoietic transcription factor RUNX1. Although CBFβ-SMMHC was previously thought to dominantly repress RUNX1, recent work suggests that CBFβ-SMMHC functions together with RUNX1 to activate transcription of specific target genes.

Targeting the …

A Bifunctional Atpase Drives Tad Pilus Extension And Retraction, Courtney K. Ellison, Jingbo Kan, Jennifer L. Chlebek, Katherine R. Hummels, GaёL Panis, Patrick H. Viollier, Nicolas Biais, Ankur B. Dalia, Yves V. Brun

Publications and Research

A widespread class of prokaryotic motors powered by secretion motor adenosine triphosphatases (ATPases) drives the dynamic extension and retraction of extracellular fibers, such as type IV pili (T4P). Among these, the tight adherence (tad) pili are critical for surface sensing and biofilm formation. As for most other motors belonging to this class, how tad pili retract despite lacking a dedicated retraction motor ATPase has remained a mystery. Here, we find that a bifunctional pilus motor ATPase, CpaF, drives both activities through adenosine 5′-triphosphate (ATP) hydrolysis. We show that mutations within CpaF result in a correlated reduction in the rates of …

Alanyl-Trna Synthetase Quality Control Prevents Global Dysregulation Of The Escherichia Coli Proteome, Paul Kelly, Nicholas Backes, Kyle Mohler, Christopher Buser, Arundhati Kavoor, Jesse Rinehart, Gregory Phillips, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Mechanisms have evolved to prevent errors in replication, transcription, and translation of genetic material, with translational errors occurring most frequently. Errors in protein synthesis can occur at two steps, during tRNA aminoacylation and ribosome decoding. Recent advances in protein mass spectrometry have indicated that previous reports of translational errors have potentially underestimated the frequency of these events, but also that the majority of translational errors occur during ribosomal decoding, suggesting that aminoacylation errors are evolutionarily less tolerated. Despite that interpretation, there is evidence that some aminoacylation errors may be regulated, and thus provide a benefit to the cell, while others …

Uncovering New Mechanisms Of Cdc34 And Cullin-Ring Activity, Spencer Hill

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ubiquitylation is a cellular regulatory system found in all eukaryotic cells, which has managed to find a role in most pathways imaginable. The system works fundamentally through the ligation of a small protein known as ubiquitin onto a substrate. Depending on the context of the ubiquitin ligation, the substrate can be directed towards a number of cellular fates, the best-studied being degradation of the substrate. While originally thought of as a signal for cellular disposal units to degrade aberrant proteins, we now know that ubiquitin plays a highly nuanced role in cellular epistasis, controlling everything from the cell cycle to …

The Perplexing Paradox Of Clostridioides (Clostridium) Difficile Infection (Cdi) - Analysis Of Anti-Germinants As Part Of Cdi Prophylaxis, Christopher Yip

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clostridioides (Clostridium) difficile infections (CDI) have become the leading cause of nosocomial antibiotic-associated diarrhea worldwide. Under normal circumstances, bacteria found in the gastrointestinal tract provide a barrier against C. difficile colonization. Upon antibiotic therapy, the protective barrier is lost as the microbial community becomes depleted thus providing the opportunity for C. difficile to colonize the human gut. Exposure to taurocholate, a bile acid produced within the mammalian gastrointestinal tract, causes C. difficile spores to begin their transition, a process known as germination, from metabolically dormant structures to toxin-producing cells. As germination is required for the onset of CDI, anti-germination compounds …

A Noncanonical Function Of The Telomerase Rna Component In Human Embryonic Stem Cells, Kirsten Ann Brenner

Arts & Sciences Electronic Theses and Dissertations

Telomeres are stretches of TTAGGG nucleotide repeats located at the ends of linear chromosomes that shorten with progressive cell division and prevent genomic instability at the cost of limiting a cell’s capacity to proliferate. This limitation can be overcome by telomerase, a ribonucleoprotein complex that elongates telomeres via reverse-transcription of the template telomerase RNA component (TERC). Recent studies have reported potential functions of TERC outside of its role in telomere maintenance. These noncanonical functions of TERC are however poorly defined, and the molecular mechanisms and biological relevance behind such functions remain elusive. Here, we generated conditional TERC knock-out human embryonic …

Activation And Regulation Of The Alkbh3-Ascc Alkylation Repair Pathway, Josh Brickner

Arts & Sciences Electronic Theses and Dissertations

DNA repair is essential to prevent the cytotoxic or mutagenic effects of various types of DNA lesions. These lesions are sensed by distinct pathways to recruit repair factors specific to type of damage. In particular, the ALKBH family of proteins recognizes and repairs specific alkylated lesions, including 1-methyladenine (m1A) and 3-methylcytosine (m3C). A major outstanding question in the field is how the AlkB homologue ALKBH3 and its associated protein partners are recruited to sites of alkylation damage and how this repair activity is regulated. Understanding the upstream signaling events that mediate recognition and repair of DNA alkylation damage is particularly …

Transcriptional Regulation Of Adipose Tissue Development By Pexrap And Med19, John Dean

Arts & Sciences Electronic Theses and Dissertations

Targeting adipose tissue function to decrease adiposity and improve insulin sensitivity could treat obesity and diabetes. How the nuclear receptor PPARγ regulates the development of two functionally distinct types of adipose tissue, brown and white fat (BAT and WAT), as well as the browning of white fat, remains unclear. Our previous studies suggest that PexRAP, a peroxisomal lipid synthetic enzyme, regulates PPARγ signaling and white adipogenesis.Here, we show that PexRAP is an inhibitor of brown adipocyte gene expression. PexRAP inactivation promoted adipocyte browning, increased energy expenditure, and decreased adiposity. Identification of PexRAP-interacting proteins suggests that PexRAP function extends beyond its …

Sideromycin Pathway Elucidation: Insights Into Salmycin Biosynthesis, Transport Paradigms, And Drug Release, Gerry Sann Macaraeg Rivera

Arts & Sciences Electronic Theses and Dissertations

Antibiotic resistance is an increasing threat in today’s society. In order to overcome resistant bacteria, it is necessary to discover new drugs with novel mechanisms of action. This work focuses on the sideromycin pathway, encompassing the biosynthetic production, mechanism of entry and hydrolysis-mediated drug release. Sideromycins are an interesting approach to combat the rise of antibiotic resistance since they provide a different avenue that overcomes problems that arise when entering the cell. The dissertation is separated into distinct sections dealing with the various areas of interest in the sideromycin pathway, particularly for the sideromycin, salmycin, produced by Streptomyces violaceus. The …

Investigating Biological Mechanisms Of Radiation Resistance In Advanced Stage Cervical Cancer, Fiona Ruiz

Arts & Sciences Electronic Theses and Dissertations

The current standard of care treatment for locally advanced cervical cancer is curative intent pelvic radiation with concurrently administered platinum chemotherapy (CRT). This treatment strategy is effective for many patients, but 33-50% of patients treated with CRT develop disease recurrence. Metastatic and recurrent cervical cancer is an incurable condition, and many of the currently available treatments are associated with significant morbidity and mortality. Identifying these patients upfront is a challenge that clinicians face when developing treatment strategies. Previous studies used to catalog the genomic and transcriptomic landscape of cervical cancer lacked high quality corresponding clinical follow up data for patients, …

Development And Application Of Mass Spectrometry-Based Protein Footprinting In Structural Proteomics, Ming Cheng

Arts & Sciences Electronic Theses and Dissertations

Integral mass spectrometry (MS) has emerged as an important tool for protein structural characterization. It readouts are a broad range of structural information, including stoichiometry, interactions, conformations and conformation change, and dynamics. Protein footprinting is a pivotal component in the intergral MS toolkit.My dissertation centers around the development and application of protein footprinting to characterize protein structure. It is divided into seven chapters.Chapter 1 serves as the introduction for integral mass spectrometry in structural proteomic.In Chapter 2, we extended the fast-photochemical oxidation of proteins (FPOP) platform by adding the trifluoromethyl radical (•CF3) as a new reagent. We discovered that •CF3 …

Elucidating Enhancer Function In Epidermal Development And Filaggrin Loss-Of-Function Variants In African American Atopic Dermatitis, Mary Elizabeth Mathyer

Arts & Sciences Electronic Theses and Dissertations

The epidermis is the outermost tissue of the skin and provides the body’s first line of defense against external assaults. The epidermis is primarily composed of keratinocytes that terminally differentiate and rise apically toward the surface to form the semipermeable barrier of the skin. A hallmark of keratinocyte terminal differentiation is the expression of genes from the Epidermal Differentiation Complex (EDC) locus. Many of the EDC protein products contribute to the structural integrity of the skin barrier, evidenced by several gene knockouts such as loricrin, and even genetic variation within gene coding sequences, that modulate the integrity of the skin …

Insight Into The Molecular Mechanisms For Microcystin Biodegradation In Lake Erie And Lake Taihu, Lauren E. Krausfeldt, Morgan M. Steffen, Robert M. Mckay, George S. Bullerjahn, Gregory L. Boyer, Steven W. Wilhelm

Great Lakes Institute for Environmental Research Publications

Microcystins are potent hepatotoxins that are frequently detected in fresh water lakes plagued by toxic cyanobacteria. Microbial biodegradation has been referred to as the most important avenue for removal of microcystin from aquatic environments. The biochemical pathway most commonly associated with the degradation of microcystin is encoded by the mlrABCD (mlr) cassette. The ecological significance of this pathway remains unclear as no studies have examined the expression of these genes in natural environments. Six metatranscriptomes were generated from microcystin-producing Microcystis blooms and analyzed to assess the activity of this pathway in environmental samples. Seventy-eight samples were collected from Lake Erie, …