Biochemistry, Biophysics, and Structural Biology Commons^™

Escherichia Coli Alanyl-Trna Synthetase Maintains Proofreading Activity And Translational Accuracy Under Oxidative Stress, Arundhati Kavoor, Paul Kelly, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNA synthetases (aaRSs) are enzymes that synthesize aminoacyl-tRNAs to facilitate translation of the genetic code. Quality control by aaRS proofreading and other mechanisms maintains translational accuracy, which promotes cellular viability. Systematic disruption of proofreading, as recently demonstrated for alanyl-tRNA synthetase (AlaRS), leads to dysregulation of the proteome and reduced viability. Recent studies showed that environmental challenges such as exposure to reactive oxygen species can also alter aaRS synthetic and proofreading functions, prompting us to investigate if oxidation might positively or negatively affect AlaRS activity. We found that while oxidation leads to modification of several residues in Escherichia coli AlaRS, unlike …

Development Of The Seqcode: A Proposed Nomenclatural Code For Uncultivated Prokaryotes With Dna Sequences As Type, William B. Whitman, Maria Chuvochina, Brian P. Hedlund, Philip Hugenholtz, Konstantinos T. Konstantinidis, Alison E. Murray, Marike Palmer, Donovan H. Parks, Alexander J. Probst, Anna-Louise Reysenbach, Luis M. Rodriguez-R, Ramon Rossello-Mora, Iain Sutcliffe, Stephanus N. Venter

Life Sciences Faculty Research

Over the last fifteen years, genomics has become fully integrated into prokaryotic systematics. The genomes of most type strains have been sequenced, genome sequence similarity is widely used for delineation of species, and phylogenomic methods are commonly used for classification of higher taxonomic ranks. Additionally, environmental genomics has revealed a vast diversity of as-yetuncultivated taxa. In response to these developments, a new code of nomenclature, the Code of Nomenclature of Prokaryotes Described from Sequence Data (SeqCode), has been developed over the last two years to allow naming of Archaea and Bacteria using DNA sequences as the nomenclatural types. The SeqCode …

Conformational Flexibility And Local Frustration In The Functional States Of The Sars-Cov-2 Spike B.1.1.7 And B.1.351 Variants: Mutation-Induced Allosteric Modulation Mechanism Of Functional Dynamics And Protein Stability, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Structural and functional studies of the SARS-CoV-2 spike proteins have recently determined distinct functional states of the B.1.1.7 and B.1.351 spike variants, providing a molecular framework for understanding the mechanisms that link the effect of mutations with the enhanced virus infectivity and transmissibility. A detailed dynamic and energetic analysis of these variants was undertaken in the present work to quantify the effects of different mutations on functional conformational changes and stability of the SARS-CoV-2 spike protein. We employed the efficient and accurate coarse-grained (CG) simulations of multiple functional states of the D614G mutant, B.1.1.7 and B.1.351 spike variants to characterize …

Ultrasound 96 Probe Device Protocol For Cancer Cell Treatment, Aisling Field, Brijesh K. Tiwari, James F. Curtin, Julie R M Mondala, Janith Wanigasekara

Articles

Ultrasound is a sound wave with frequencies ranging between 20 kHz and 20 MHz. Ultrasound is able to temporarily and repeatedly open the BBB safely and enhance chemotherapeutic delivery without adverse effects. This novel technique in drug delivery benefits from the powerful ability of ultrasound to produce cavitation activity. Cavitation is the generation and activity of gas-filled bubbles in a medium exposed to ultrasound. As the pressure wave passes through the media, gas bubbles expand at low pressure and contract at high pressure. This leads to oscillation which produces a circulating fluid flow known as microstreaming around the bubble with …

Plasma Induced Reactive Oxygen Species-Dependent Cytotoxicity In Glioblastoma 3d Tumourspheres, Janith Wanigasekara, Carlos Barcia, Patrick J. Cullen, Brijesh Tiwari, James F. Curtin

Articles

The aim of this study was to determine the effects of a pin‐to‐plate cold atmospheric plasma (CAP) on U‐251 MG three‐dimensional (3D) glioblastoma spheroids under different conditions. 3D tumorspheres showed higher resistance to the CAP treatment compared to 2D monolayer cells. A single CAP treatment was able to induce cytotoxicity, while multiple CAP treatments augmented this effect. CAP was also able to induce cytotoxicity throughout the tumoursphere, and we identified that reactive oxygen species(ROS) plays a major role, while H2O2plays a partial role in CAP‐induced cytotoxicity in tumour-spheres. We conclude that ROS‐dependent cytotoxicity is induced uniformly throughout glioblastoma and epidermoid …

The Role Of Ehd2 In Endothelial Cells, Rachael Judson

Electronic Theses and Dissertations

The role of EHD2 in terms of Cav1 interaction had not been previously characterized and was the main goal of this research. Cav1 has been shown to lead to the ubiquitination of Rac1. Because of this, the role of EHD2 in Rac1 regulation was investigated. An increase in long-term migration in endothelial cells was observed and suggested that EHD2 impacts the RhoA pathway instead of the Rac1 pathway. This lead to the hypothesis that EHD2 controls a part of the RhoA pathway. This hypothesis is supported by the loss of filamentous actin and an increase in serrated junctions in cells …

Inhibition Of De Novo And The Prion-Like Spread Of Amyloidogenesis Using In Vitro And In Vivo Disease Models, Johnson Anazoba Joseph

Electronic Theses and Dissertations

The aberrant fibrous, extracellular, and intracellular proteinaceous deposits in cells, organs and tissues are referred to as amyloids. These deposits are dominated by β-sheet structures that have been implicated in several neurodegenerative diseases and cancer. In this work, the types of amyloidosis studied include Parkinson’s disease (PD) using UA196 and NL5901 strains of Caenorhabditis elegans (C. elegans), Alzheimer’s disease (AD) using GMC101 strain of C. elegans, and cancer-associated mutant p53 aggregation in MIA PaCa-2 mutant cells. Several molecules including SK-129, NS132, NS163, bexarotene, a polyphenol (-)-epi-gallocatechine gallate (EGCG), ADH40, RD148, and RD242 were screened in vitro and in …

The Pathophysiological Mechanisms Of Alzheimer's Disease; Investigating Therapeutic Interventions For Disease Onset, Alexandra A. Sandberg

Electronic Theses and Dissertations

Alzheimer’s Disease is a multifarious disease that progressively affects more people as both the proportion of older adults in the population and life expectancy increase in both the United States and worldwide. This devastating disease is a result of rampant neuronal loss in the memory centers of the brain that robs the independence of those who are diagnosed and places a heavy burden on those who care for them. Traditionally speaking, research has focused on the hallmark pathology of amyloid plaques, targeting them to try and prevent disease onset. However, countless failures in clinical trials aimed at this said pathology …

Antioxidant Biomarkers And Nutraceutical Therapeutics In Neurodegeneration And Neurotrauma, Lilia A. Koza

Electronic Theses and Dissertations

Mild traumatic brain injury (mTBI), yielding a Glascow Coma Scale of 13-15, is the most commonly occurring severity of TBI. Pathology from mTBI consists of blood brain barrier disruption, neuroinflammation, oxidative stress, excitotoxicity, mitochondrial dysfunction, protein aggregation, axonal degeneration, and resulting neuronal death. These processes deplete the body’s endogenous antioxidant system. We report a retrospective analysis of antioxidant blood biomarkers in patients with a history of mTBI from a local sports medicine clinic, Resilience Code. We found persistent sex-specific antioxidant depletions in mTBI patients associated with worsened symptomology.

Certain populations, such as athletes, are at high risk for repetitive mTBI …

Organellar Zn2+ Homeostasis And The Role Of Trpml Channels In Neuronal Lysosome Physiology And Axonal Transport, Taylor Franklin Minckley

Electronic Theses and Dissertations

Zinc (Zn²⁺) is crucial for proper cellular function, and as such it is important to measure and track Zn²⁺ dynamics in living cells. Fluorescent sensors have been used to estimate Zn²⁺ content of subcellular compartments, but little is known about endolysosomal Zn2+ homeostasis. Similarly, although numerous sensors have been reported, it is unclear whether and how Zn²⁺ can be released from intracellular compartments into the cytosol due to a lack of probes that can detect physiological dynamics of cytosolic Zn²⁺. My dissertation started with comparing and characterizing different Zn²⁺ sensors including the …

The Effects Of Neuronal Growth Factors On Lps-Activated Schwann Cells, Caitlyn E. Henry, Peyton Kimmel, Angela Asirvatham Ph.D.

Student Research Poster Presentations 2022

Schwann cells (SCs) are the principal support cells of neurons in the peripheral nervous system, that both myelinate axons for the rapid conduction of electrical impulses as well as assist in axonal repair during nerve injury. During nerve injury, SCs secrete tumor necrosis factor alpha (TNF-α)^1,5,6 and other proinflammatory mediators^1,6, attracting macrophages to the site of injury to induce inflammation and clear myelin debris.^1,6 Once the debris is cleared, the neuron stimulates SC proliferation by secreting neuronal mitogens, such as heregulin^3,4, and an unknown factor that activates the cAMP pathway³, an important …

Simulation Of An Inflammatory Model Using Schwann Cells, Caitlyn Henry, Peyton Kimmel, Angela Asirvatham

Student Research Poster Presentations 2022

During peripheral nerve injury, the myelin surrounding the neuronal axons is damaged, initiating an inflammatory response to remove myelin debris. Once myelin debris is cleared, Schwann cells acquire a proliferating phenotype which allows them to grow and divide so that remyelination can occur. The neuron stimulates Schwann cell division by secreting growth factors, like heregulin, and an unknown growth factor that activates the cAMP pathway. Although the role of cAMP in axonal regeneration is well-known, not much has been explored about its function in Schwann cells during nerve injury and inflammation. To simulate an inflammatory environment, the S16 Schwann cell …

Characterization Of Cofilin And Its Potential Role In The Epha4 Pathway, Brian Donald Condron

Master's Theses and Doctoral Dissertations

EphA4 is a receptor tyrosine kinase that is responsible for cellular adhesion and locomotion using repulsion signaling in early development of Xenopus laevis. EphA4 regulates cellular locomotion by controlling proteins within its signal transduction pathway, which may include the protein cofilin. Cofilin actively severs and removes actin monomers, thus altering the actin cytoskeleton, leading to the cessation of cellular crawl. During the gastrulation phase of embryonic development, individual cells are relocating to create the three primary germ layers of the organism. Failure of this process to occur results in attrition of the embryos, frequently by way of embryonic exogastrulation. …

Phosphatidylserine Externalization On Non-Apoptotic Cells And Lipid Scramblases In C. Elegans, Julia Frondoni

Electronic Theses and Dissertations

Cell corpse clearance is key for animals to avoid inflammation and autoimmune disease. To better understand the “eat me” signal of phosphatidylserine (PS) exposure for non-apoptotic corpse clearance, we attempted to disrupt the externalization of PS on C. elegans polar bodies. The second polar body undergoes a non-apoptotic form of cell death, loses membrane integrity, externalizes PS and is cleared by embryonic cells during early development. During apoptotic and necrotic cell death, PS asymmetry is disrupted by lipid scramblases, which translocate phospholipids between the leaflets of the lipid bilayer. We found neither apoptotic nor necrotic scramblases are required for PS …

Investigation Of Nuclear Envelope-Associated Progeria Proteins During Nuclear Envelope Rupture, Rhiannon Marie Sears

Dissertations and Theses

The nuclear envelope (NE) is a specialized extension of the endoplasmic reticulum critical for the proper protection and organization of the genome. This interphase-only structure is host to several proteins and their interacting constituents that have various and diverse cellular roles. Mutations in NE constituents are associated with several human diseases. A subset of these diseases, known as progeria syndromes, are characterized by the premature presentation of physiological aging in a variety of tissues. Mutations in the genes LMNA and BANF1, which encode the A-type lamins and barrier-to-autointegration factor (BAF), can lead to these multisystem progeroid diseases. Though the underlying …

Phip Variants Associated With Chung–Jansen Syndrome Disrupt Replication Fork Stability And Genome Integrity, Neysha Tirado-Class, Caitlin Hathaway, Wendy K. Chung, Huzefa Dungrawala

Molecular Biosciences Faculty Publications

Chung–Jansen syndrome (CJS) is a rare, autosomal dominant disorder characterized by developmental delay, intellectual disability/cognitive impairment, behavioral challenges, obesity, and dysmorphic features. CJS is associated with heterozygous variants in PHIP (Pleckstrin-Homology Interacting Protein), a gene that encodes one of several substrate receptors for Cullin4-RING (CRL4) E3 ubiquitin ligase complex. Full-length PHIP, also called DCAF14, was recently identified to function as a replication stress response protein. Herein, we report the identification of two PHIP missense variants identified by exome sequencing in unrelated individuals with CJS. The variants p.D488V and p.E963G occur in different functional elements of DCAF14-WD40 repeat domain and pleckstrin …

Sequence Properties Of An Intramolecular Interaction That Inhibits P53 Dna Binding, Emily Gregory, Gary W. Daughdrill

Molecular Biosciences Faculty Publications

An intramolecular interaction between the p53 transactivation and DNA binding domains inhibits DNA binding. To study this autoinhibition, we used a fragment of p53, referred to as ND WT, containing the N-terminal transactivation domains (TAD1 and TAD2), a proline rich region (PRR), and the DNA binding domain (DBD). We mutated acidic, nonpolar, and aromatic amino acids in TAD2 to disrupt the interaction with DBD and measured the effects on DNA binding affinity at different ionic strengths using fluorescence anisotropy. We observed a large increase in DNA binding affinity for the mutants consistent with reduced autoinhibition. The ΔΔG between DBD and …

Functionalization Of Chitosan Based Microparticles For In Vitro 3d Culture Of Human Liver Cells, William Imes

Williams Honors College, Honors Research Projects

Previous work involving 3D culture of human liver cells with fluorinated chitosan based microparticles has shown that their incorporation provides needed structural cues that the culture of cells alone does not provide, such as increased gas transport. However, using bare microparticles to grow large 3D cellular structures is not practical as they tend to collapse before any meaningful research can be done on them. It is proposed that this is because of the lack of extracellular matrix (ECM)components within pure cell culture in vitro, which in their absence cannot adequately facilitate biochemical communication and adhesion between cells. It is …

Salivary Gland Stromal Heterogeneity And Epithelial Controls, Nicholas L. Moskwa

Legacy Theses & Dissertations (2009 - 2024)

Organogenesis is the process organs go through where cellular communications coordinate all a developing organ needs. What organs need are more cells, in the right place, doing the right job. In the salivary gland, we know that stromal cells are important for organogenesis and that they coordinate the epithelium’s form and functions. However, specific stromal contributions have focused on epithelial quantity and placement. There is less information about how the stroma directs the epithelium towards certain functions. Here we used organoids as a model for understanding what stromal signaling directs epithelial cell fate. We found that stromal cell state is …

Exploring The Roles Of Stress, Codon Usage, And Rna Modifications In Myotonic Dystrophy Type 1, Afrooz Golestanian

Legacy Theses & Dissertations (2009 - 2024)

Myotonic dystrophy (DM), the most common form of muscular dystrophy, is a neuromuscular disease caused by microsatellite repeat expansions. It can represent a multi-systemic autosomal dominant disease with DM1 and DM2 subtypes. A cytosine-thymine-guanine (CTG) triplet repeat in the 3’ untranslated region (3’UTR) of myotonic dystrophy protein kinase (DMPK) gene causes DM1 disease, which leads to the production of a longer, abnormal and toxic mRNA. The toxic DMPK mRNA sequester the splicing proteins such as Muscle blind-like (MBNL) and rbFOX which leads to gene expression alteration. Repeat associated non-AUG (RAN) translation also occurs in DM1. Mitochondrial dysregulation has also been …

A Study Of Cobalt (Iii) Oxide Nanoparticle Delivery Of Sirna Molecules Directed Against Signaling Intermediates Of The P2y2 Receptor, Rachel Blair Stroud

Graduate Theses/Dissertations

G protein-coupled receptors are evolutionarily ubiquitous sensors of extracellular signals, propagating intracellular signal cascades through heterotrimeric G proteins. P2Y₂ receptors are GPCRs which are activated by extracellular nucleotides to mediate signaling cascades via Gαq coupling. Many GPCRs are subject to a common mechanism for signal termination involving phosphorylation of the C-terminal tail followed by β-arrestin binding and subsequent endocytic internalization of the complex. This effect has been described for the P2Y₂ R in the 1321N1 astrocytoma cell line, and UTP-induced activation and desensitization profiles have been previously defined. There is need to develop molecular vehicles for safe and …

Further Investigation Of The Initiating Mechanism Of The Type I Collagen Glomerulopathy, Matthew James Freese

Graduate Theses/Dissertations

The progressive accumulation of collagen and other extracellular matrix proteins in the renal mesangium results in fibrosis, glomerulosclerosis, and eventual renal failure. Mice deficient in integrating α2(I) collagen into the type I collagen structure, termed Col1a2-deficient mice, model kidney fibrosis through the condition Type I Collagen Glomerulopathy, because homotrimeric type I collagen accumulates extracellularly in the mesangium of renal glomeruli. Accumulation of homotrimeric type I collagen compresses blood vessels in glomeruli, which reduces filtration, increases pressure, and results in fibrosis. Picrosirius red (PSR) staining was used on Col1a2 deficient and wildtype mice to evaluate collagen deposition. Histological evaluation and …

Deconstructing Brown Adipocyte Neogenesis In Brown And White Adipose Tissue, Rayanne Burl

Wayne State University Dissertations

Global incidence of Type 2 Diabetes (T2D) has reached epidemic proportions, and increasing evidence indicates that dysfunctional adipose tissue is an important contributor to the pathogenesis of T2D. Expanding brown adipocyte (BA) populations within adipose tissues through adrenergic activation improves energy balance and insulin sensitivity. In order to exploit this remodeling of adipose tissue for therapeutic benefit, we need to understand the mechanisms by which adrenergic signaling expand populations of BAs in vivo. These studies utilized single-cell RNA-sequencing and transgenic mouse models, in combination with single-molecule fluorescence in situ hybridization (smFISH) and immunoistochemical analysis, to study BA neogenesis in vivo. …

Determining The Effects Of Chemical Exposure On Hepatocyte Mitochondrial Networks And Cell Viability, Bethany Eaton

All Master's Theses

Mitochondria are cellular organelles that are becoming more recently studied. One of their main functions is the production of energy through cellular respiration, which is crucial to cell life. However, they are also associated with numerous disease states. It is hypothesized that reactive oxygen species (ROS), largely produced in mitochondria, induce oxidative stress and affect mitochondrial morphology along with cell viability. This study compares chemical exposure of menadione, an ROS producer, and phthalates (plasticizers) on two mouse hepatocyte cell lines to determine the effects they have on mitochondrial morphology and cell viability. Three experiments were performed to analyze the effects …

The Role Of Protein Tyrosine Phosphatase Receptor Type F In Intestinal Homeostasis And Colorectal Cancer, Ashley T. Skaggs

Theses and Dissertations--Molecular and Cellular Biochemistry

Protein phosphorylation defines one of the most important regulatory mechanisms in cell signaling. PTPRF, protein tyrosine phosphatase receptor type F, belongs to the class I R2A subfamily of protein tyrosine phosphatases (PTP). The overall objective of this dissertation is to investigate the molecular mechanisms by which PTPRF regulates normal and cancer stem cells by controlling Wnt signaling.

Dysregulation of Wnt signaling promotes the initiation and progression of colorectal cancer (CRC). We first determined the functional important of PTPRF in regulating Wnt signaling in CRC. Combining cell culture, 3D tumor organoid and xenograft models, results from our study establish PTPRF as …

A Multidisciplinary Characterization Of The Enzymology And Biology Of Reversible Glucan Phosphorylation In Toxoplasma Gondii , Robert Murphy

Theses and Dissertations--Molecular and Cellular Biochemistry

Toxoplasma gondii is an opportunistic, protozoan parasite of all warm-blooded animals, infecting roughly one-third of humans worldwide. Humans acquire infections by consuming T. gondii tissue cysts in undercooked meat or from oocysts shed in cat feces. Encysted parasites convert into rapidly growing tachyzoites that disseminate throughout the body, defining the acute phase of infection. Under host immune pressure, tachyzoites convert into bradyzoites that populate tissue cysts found in CNS or muscle tissue and persist for the lifetime of the host, defining the chronic phase of infection. Tissue cysts are responsible for transmission via carnivory, but also possess the ability to …

Development Of Novel Pyridazine Derivatives And Drug Delivery Systems Against Dengue, Janae A. Culmer

College of Graduate Studies: Theses & Dissertations

The lack of approved vaccines, medications and treatment regimens has significantly contributed to the rapid spread of mosquito-borne viruses such as Dengue and Zika virus. The complex immunopathology of these viruses presents limitations for the development and implementation of a definitive, safe and effective approach to combat infections.Previous research has demonstrated that vector control strategies such as the elimination of larval habitats, larviciding with insecticides, the use of biological agents and the application of adulticides have been unsuccessful in the reduction of viral transmission leading to the need for the continued development of antivirals. This research proposes an approach for …

Tissue And Sex-Specific Rna Editing During Induced Acute Inflammation, Claire E. Nichols

Graduate Theses/Dissertations

A-to-I RNA editing is a process where select adenosine (A) nucleotides are deaminated by an editing enzyme, ADAR, to become inosines (I) in RNA transcripts. RNA editing can affect the sequence of the encoded protein and the regulation of the RNA. ADAR1 also plays a role in regulating innate immunity and its expression is upregulated during inflammation. Current data on the effects of increasing ADAR1 on RNA editing is limited, and most studies are completed only in male animals. We are interested in expanding RNA editing data to include female animals. Lipopolysaccharide (LPS) was used to induce acute inflammation and …

Nutrient Scarcity And Cellular Cooperation In A Clonal Hydroid, Weam S. El Rahmany

Graduate Research Theses & Dissertations

Biological complexity forms when lower-level units (e.g., genes, cells, organisms) cooperatively band together. This complexity may be exemplified by multicellularity, the cooperation between the cells of the same species, or symbiosis, cooperation between the cells of different species. This cooperation is under continual threat, as defection, the opposite of cooperation, is favored by default by lower-level units (i.e., cells). Animal cancers may be the most well-known phenomena that exemplify the concept of cellular defection. Cancer cells have been shown to feature morphological and metabolic traits, developed through differential gene expression or mutations, that favor their growth at the cost of …

Xrcc4 And Mre11 Roles And Transcriptional Response To Repair Of Talen-Induced Double-Strand Dna Breaks, Ronald Benjamin, Atoshi Banerjee, Xiaogang Wu, Corey Geurink, Lindsay Buczek, Danielle Eames, Sara G. Trimidal, Janice M. Pluth, Martin R. Schiller

Health Physics and Diagnostic Sciences Faculty Research

Double-strand breaks (DSB) are one of the most lethal forms of DNA damage that, if left unrepaired, can lead to genomic instability, cellular transformation, and cell death. In this work, we examined how repair of transcription activator-like effector nuclease (TALEN)-induced DNA damage was altered when knocking out, or inhibiting a function of, two DNA repair proteins, XRCC4 and MRE11, respectively. We developed a fluorescent reporter assay that uses TALENs to introduce DSB and detected repair by the presence of GFP fluorescence. We observed repair of TALEN-induced breaks in the XRCC4 knockout cells treated with mirin (a pharmacological inhibitor of MRE11 …