Molecular Biology Commons^™

Establishment Of A Hek293t Cell Model System To Investigate Direct Intracellular Interactions Between Amyloid-Β (Aβ) And The Nlrp3 Inflammasome, Cristina Sinobas Pereira

Dissertations

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia worldwide. While Amyloid-β (Aβ) aggregation is a defining pathological feature, increasing evidence highlights chronic neuroinflammation as a critical contributor to disease progression. Soluble Aβ assemblies can act as damage associated molecular patterns (DAMPs) including activation of the NLRP3 inflammasome, which links amyloid pathology to sustained inflammatory responses in the brain (Heneka et al., 2015; Nakanishi et al., 2018). However, the molecular mechanisms by which specific Aβ conformations influence inflammasome assembly remain incompletely understood.This study aimed to investigate whether distinct aggregation states of amyloid β42 (Aβ42) are …

Newer Insights Into Mmtv Replication: The Human Retroviral Proteins Hiv-1 Tat And Htlv-1 Tax Can Transactivate The Mmtv Novel 5’ Element, Thanumol Abdul Khader

Dissertations

The mouse mammary tumor virus (MMTV) is a prototypic betaretrovirus that causes breast cancer in mice. MMTV regulates its gene expression both at the transcriptional and post transcriptional levels. It has hormonally-regulated promoters controlled by negative regulatory factors in a tissue-specific manner. Recently, we identified a novel 24-nucleotide region at the 5' end of the MMTV genome crucial for MMTV gene expression. Its deletion resulted in disruption of MMTV transcript elongation and stability, leading to a complete loss of Gag gene expression. This conserved element is present within the bifurcated stem loop 4, responsible for gRNA dimerization and encapsidation, into …

Exploring Topological Phonons In Different Length Scales: Microtubules And Acoustic Metamaterials, Ssu-Ying Chen

Dissertations

The topological concepts of electronic states have been extended to phononic systems, leading to the prediction of topological phonons in a variety of materials. These phonons play a crucial role in determining material properties such as thermal conductivity, thermoelectricity, superconductivity, and specific heat. The objective of this dissertation is to investigate the role of topological phonons at different length scales.

Firstly, the acoustic resonator properties of tubulin proteins, which form microtubules, will be explored The microtubule has been proposed as an analog of a topological phononic insulator due to its unique properties. One key characteristic of topological materials is the …

Reactive Oxygen Species And Weak Magnetic Fields: Unraveling The Mechanisms Of Planarian Regeneration And Tissue Growth, Luke James Kinsey

Dissertations

Reactive oxygen species (ROS) play a critical role in basic cellular behaviors such as apoptosis, proliferation, and differentiation. These molecules once thought to be harmful byproducts of metabolism, are also required for many complex and ubiquitous processes like wound healing, development, and regeneration. This study investigates the influence of ROS on planarian regeneration, with a particular focus on ROS dynamics in stem cell-mediated tissue growth. Data reveal that modulation of ROS levels leads to changes in cellular behaviors and tissue growth outcomes. Inhibition of ROS accumulation blocks stem cell proliferation and tissue growth, preventing planarian regeneration, while partial ROS accumulation …

Molecular Mechanisms Of Natural And Synthetic Compounds Against Breast And Colon Cancer, Aysha Hamad Alneyadi

Dissertations

Cancer is a complex disease with various causes, including genetic mutations, viruses, chemical agents, and lifestyle factors. Although numerous studies have been conducted to develop a cure or novel medications for cancer, no standout treatment has been found. In this project, the use of various natural and synthetic compounds as potential cancer treatments was investigated using triple-negative breast cancer (TNBC) and colon cancer cells. The cancer therapy strategies investigated were based on plant-derived therapuetic approaches including an essential oil (Origanum majorana essential oil), a pure phytochemical (Carnosol), and newly developed synthetic drugs (Chromenes drevatives; C1 and C2). This study …

Effects Of Membrane Components On The Oligomerization Of Amyloid-Β (Aβ) In Alzheimer Disease, Jhinuk Saha

Dissertations

Deposition of extracellular proteinaceous plaques of amyloid-β (Aβ) is one of the major hallmarks of Alzheimer disease (AD). Although, insoluble high molecular fibrils of Aβ are the main constituents of the senile plaques in AD, low molecular weight soluble Aβ oligomers have emerged as the key toxic species involved in memory impairment and neuronal cell death in AD. The process for generation of oligomers can be highly diverse and can involve homotypic interactions of Aβ as well as heterotypic interaction of Aβ with other macromolecules. Previously, the generation of Aβ oligomers with distinct biochemical and biophysical characteristics catalyzed non-esterified fatty …

Characterization And Genomic Analysis Of Two Escherichia Coli O157:H7 Bacteriophages Isolated From Pigeons, Mohamad I. Alolama

Dissertations

Enterohemorrhagic Escherichia coli, also known as EHEC, is a subset of Shiga toxin-producing E. coli (STEC), and it has recently been identified as one of the principal foodborne pathogens. E. coli O157:H7 is the most important serotype of STEC for its role in causing foodborne illnesses. E. coli O157:H7 could cause various gastroenteritis symptoms such as diarrhea, hemolytic uremic syndrome, hemorrhagic colitis, and thrombotic thrombocytopenic purpura and may cause death. Elimination of E. coli O157:H7 during food processing and storage is a possible solution. Bacteriophages have a significant impact on bacterial populations in nature due to their ability to …

Characterization Of Tick And Host-Associated Factors Linked To Induction Of Alpha-Gal Syndrome., Surendra Raj Sharma, Surendra Raj Sharma

Dissertations

Alpha-Gal Syndrome (AGS) is a delayed allergic reaction caused by specific IgE antibodies to the oligosaccharide galactose-α-1,3-galactose (α-gal) present in red meat. AGS is a growing concern globally, with over 34,000 confirmed cases in the United States alone. Studies have linked AGS to tick bites, which sensitizes hosts against α-gal antigens and elevates α-gal specific IgE. This dissertation investigates the role of tick and host-associated factors in AGS development. Microbiome analysis of Am. americanum ticks revealed a comprehensive core microbiome profile and showed that new Fransiella-like endosymbionts dominate and outcompete conventional tick Coxiella endosymbionts. Ticks subjected to tetracycline treatment showed …

Probing Amyloid-Beta Protein Structure And Dynamics With A Selective Antibody, Shikha Grover

Dissertations

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. The AD brain is characterized by significant neuronal loss and accumulation of insoluble fibrillar amyloid-β protein (Aβ) plaques and tau protein neurofibrillary tangles in the brain. However, over the last decade, many studies have shown that the neurodegenerative effect of Aβ may in fact be caused by various soluble oligomeric forms as opposed to the insoluble fibrils. Furthermore, the data suggest that a pre-fibrillar aggregated form, termed protofibrils, mediates direct neurotoxicity, and triggers a robust neuroinflammatory response.

Antibodies targeting the various conformation of Aβ are important therapeutic agents to prevent the progression …

Role Of Micrornas In Intestinal Inflammation And Barrier Homeostasis After Alcohol And Burn Injury, Caroline J. Herrnreiter

Dissertations

MicroRNAs are small noncoding RNA molecules that negatively regulate gene expression. Within the intestinal epithelium, miRNAs play a critical role in gut homeostasis and aberrant miRNA expression has been implicated in various disorders associated with intestinal inflammation and barrier disruption. In this study, we sought to profile changes in intestinal epithelial cell miRNA expression after alcohol and burn injury and elucidate their impact on inflammation and barrier integrity. In a more targeted approach, we began by focusing on anti-inflammatory miRNAs that, when downregulated, could exacerbate inflammation and result in intestinal barrier disruption. Using a mouse model of acute ethanol intoxication …

Dynamic Control Of The Cardiac Calcium Pump, Sean Robert Cleary

Dissertations

The sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) sequesters Ca2+ into the endoplasmic reticulum of cells to establish a reservoir for Ca2+ signaling. In the heart, the activity of this transporter is tightly controlled via direct interactions with two competing regulatory micropeptides: phospholamban (PLB) and dwarf open reading frame (DWORF). PLB inhibits SERCA, while DWORF activates SERCA. These competing interactions determine cardiac performance by modulating the Ca2+ signals that drive the contraction/relaxation cycle. Previous studies indicated these SERCA-micropeptide interactions are Ca2+-sensitive; SERCA binds PLB more avidly at low cytoplasmic [Ca2+] but binds DWORF better when [Ca2+] is high. Here, FRET-microscopy demonstrated that this …

Investigating The Involvement Of The Tick Vector In The Induction Of Alpha-Galactose Hypersensitivity (Alpha-Gal Syndrome, Red Meat Allergy) In The United States., Gary Crispell

Dissertations

Alpha-gal syndrome (AGS or sometimes called red meat allergy) is a result of the development of specific IgE antibodies to the oligosaccharide galactose-α-1,3-galactose (α-gal) after a person has had exposure to tick bites. This dissertation investigates four common tick species found in North America: the lone-star tick (Amblyomma americanum), the Gulf-Coast tick (Amblyomma maculatum), the American dog tick (Dermacentor variabilis), and the black-legged tick (Ixodes scapularis) for the presence of α-gal by utilizing a combination of immunoproteomic approaches and carbohydrate analysis techniques.

Anti-α-gal IgM antibodies (M86) were used in immunoblotting to detect …

The Roles Of A Probiotic Exopolysaccharide In Breast Cancer, Mai Rachel Nguyen

Dissertations

breast cancer, exopolysaccharide, probiotic

Investigating The Role Of Fun30, A Chromatin Remodeler, In Dna Repair, Mehwish Iqbal

Dissertations

The repair of DNA double-strand breaks (DSBs) is crucial for maintaining genome stability. DSB repair needs to take place within the complex organization of the chromatin, and this requires changes in the chromatin structure adjacent to DSB sites. These changes occur through covalent histone modifications that alter histone-DNA contacts as well as by the action of ATP-dependent chromatin remodelers. Many chromatin remodelers, including Fun30, are involved in DSB repair. Fun30 facilitates DNA end resection at DSB site during the homologous recombination repair pathway. Apart from its role in DNA repair, Fun30 promotes gene silencing at heterochromatic loci such as telomeres, …

Delineating The Exocytic Fusion Machinery Required For Mast Cell Exocytosis, Pratikshya Adhikari

Dissertations

Mast cells undergo exocytosis to release a wide array of inflammatory mediators by utilizing membrane fusion proteins-SNAREs (soluble-N-ethyl-maleimide sensitive factor attachment protein receptor) along with essential regulatory Munc18 and Munc13 proteins. Accumulating evidence in mast cell biology suggests the existence of distinct pools of mast cell mediators. However, the precise mechanism underlying the release of each mast cell mediator is not clear. To determine whether different exocytic machineries are required for differential mediator release, I used reconstitution to investigate the differential role of Munc18s in fusion machinery regulation. Munc18a and Munc18c stimulated VAMP2 and VAMP3-mediated lipid mixing, whereas Munc18b only …

Granulins In Norm And Neurodegenerative Pathologies, Anukool Bhopatkar

Dissertations

Granulins (GRNs) are small, cysteine-rich modules produced from the proteolytic cleavage of the precursor protein called progranulin (PGRN). GRNs are present in the form of seven tandem repeats within the precursor and are known to be produced in the extracellular and in lysosomal environments. In physiology, PGRN and GRNs plays pleiotropic roles such as neuronal growth and differentiation, immunomodulation, wound healing. Recent studies have implicated pathological role for PGRN in Alzheimer disease (AD) and frontotemporal dementia (FTD) but specific mechanism(s) remains unclear. However, potential interactions between GRNs and Ab42 and TDP-43 seem like a plausible underlying mechanism. Studies presented here …

Dicer Represses Antiviral Innate Immunity Pathways In Mouse Embryonic Stem Cells, Chandan Gurung

Dissertations

Recent studies have demonstrated that embryonic stem cells (ESCs) are deficient in expressing type I interferons (IFN), the cytokines that play key roles in antiviral responses. However, the underlying molecular mechanisms and biological implications of this finding are poorly understood. In this study, I used a synthetic RNA-based assay that can simultaneously assess multiple forms of antiviral responses in ESCs. Dicer is an enzyme essential for RNA interference (RNAi), which is used as a major antiviral mechanism in invertebrates but not clear in vertebrates. RNAi activity is detected in wild-type ESCs but is abolished in Dicer knockout ESCs (D−/−ESCs) as …

Molecular Mechanism Of Action Of The Natural Polyphenolic Compound And The P300 Inhibitor “Carnosol” Against The Triple Negative Breast Cance, Halima Ali Mohammed Salem Alsamri

Dissertations

Carnosol, a naturally occurring Phyto polyphenol found in sage, oregano, and rosemary, has been extensively studied by our laboratory for its anticancer effects in various types of cancer. In human Triple-Negative Breast Cancer (TNBC), carnosol was shown to inhibit cellular viability, colony growth, induced cell cycle arrest, autophagy, and apoptosis. Nonetheless, very little is known about the molecular mechanism of action. In the current study, the ability of carnosol to inhibit metastasis and tumour growth was examined. Wound healing and invasion assays revealed that carnosol inhibited migration and invasion at non-cytotoxic concentrations of MDA-MB-231 cells. Also, carnosol was found to …

Human 5’-Tailed Mirtrons Are Processed By Rnasep, Mohammad Farid Zia

Dissertations

Approximately a thousand microRNAs (miRNAs) are documented from human cells. A third appear to transit non-canonical pathways that typically bypass processing by Drosha, the dedicated nuclear miRNA producing enzyme. The largest class of non-canonical miRNAs are mirtrons which eschew Drosha to mature through spliceosome activity. While mirtrons are found in several configurations, the vast majority of human mirtron species are 5’-tailed. For these mirtrons, a 3’ splice site defines the 3’ end of their hairpin precursor while a “tail” of variable length separates the 5’ base of the hairpin from the nearest splice site. How this tail is removed is …

The Role Of The Msaabcr Operon In Cell Wall Integrity And Programmed Cell Death During Biofilm Development, Bibek G C

Dissertations

Staphylococcus aureus is an important human pathogen in both community and health care settings. Biggest challenges with S. aureus as a pathogen is its ability to acquire antibiotic resistance and produce robust biofilms. In this work, we investigated the nature of the cell wall defect in the msaABCR operon mutant in the Mu50 (VISA) and USA300 LAC methicillin-resistant Staphylococcus aureus (MRSA) strains. Results showed that msaABCR-mutant cells had decreased cell wall thickness and cell wall crosslinking in both strains. These defects are most likely due to increased murein hydrolase activity and/or nonspecific processing of murein hydrolases mediated by increased …

Modeling And Analysis Of Intracellular Signaling Networks And Cellular Decisions, Mustafa Ozen

Dissertations

Developing molecular network analysis methods is important due to their applications on complex biological systems such as target discovery, development of drugs, discovering drug effects, and finding treatments for many complex diseases, e.g., cancer, autoimmune, and mental disorders. An example of analysis techniques is the fault diagnosis analysis, in which the purpose is to quantify how much vulnerable the entire network is to dysfunction of one or multiple molecules. Such analysis can be done after proper network models are implemented, trained, and tested against the experimental data. In this dissertation, a Boolean modeling framework is implemented and methods to train …

Molecular Mechanism Of Cyanobacteria Circadian Clock Oscillator And Effect Of Co Factors On Its Oscillation, Manpreet Kaur

Dissertations

The circadian rhythms arise as an adaptation to the environmental 24-hour day and night cycle due to Earth's rotation. These rhythms prepare organisms to align their internal biological activities and day to day behavior or events with the environmental change of the 24-hour day and night cycle. Circadian rhythms are found widely in all living kingdoms of life on Earth. Cyanobacteria are photosynthetic prokaryotes which first used to study these circadian rhythms. Among cyanobacterial species, Synechococcus elongatus PCC 7942 (henceforth, S. Elongatus) is the simplest organism with a durable and sturdy circadian clock and is study as a model organism. …

Interactions Of The Nlrp3 Inflammasome Complex, Nyasha Makoni

Dissertations

The innate immune system is the first line of defense in response to invasion by pathogens. One of the major pathways in the innate immune system involves a three-protein complex known as the NLRP3 inflammasome. This complex comprises of NLRP3, ASC, and procaspase-1. In response to stimuli, the inflammasome assembles to activate caspase-1 which subsequently facilitates production of interleukin-1β (IL-1β), an inflammatory cytokine. The NLRP3 inflammasome has been implicated in a variety of inflammatory disorders including Alzheimer’s disease (AD). Amyloid beta (Aβ) is the protein that causes AD and Aβ deposits in the brain activate microglia resulting in chronic inflammation. …

Evaluation Of The Genetic And Structural Variations Of Camel Hemoglobin, Amanat Ali

Dissertations

The single-humped Arabian camel (Camelus dromedarius) thrives in the hot arid Arabian desert. Many unique adaptations permit it to accomplish this. Camel erythrocytes or red blood cells (RBCs) have a peculiar elliptical shape and are amenable to large variations in physical conditions resulting from dehydration and rehydration cycles. The oxygen transport protein hemoglobin is found abundantly in RBCs and is also believed to behave differently in camels. While several physiological and biochemical studies have been performed on camel hemoglobin, very little is known about genetic and structural adaptions in this protein. The camel genome harbors several unique variations …

1,4-Dioxane Biodegradation In Propanotrophs: Molecular Foundations And Implications For Environmental Remediation, Li Fei

Dissertations

1,4-Dioxane (dioxane) has emerged with an escalating concern given its human carcinogenicity and widespread occurrence in groundwater. Bioremediation is promising as an effective and cost-efficient treatment alternative for in situ or ex situ cleanup of dioxane and co-existing pollutants in the field. Soluble di-iron monooxygenases (SDIMOs) are reputed for their essential roles in initiating the cleavage of dioxane and other pollutants. In this doctoral dissertation, molecular foundations for SDIMOs-mediated dioxane biodegradation are untangled to promote the development and implication of site-specific bioremediation and natural attenuation strategies. This dissertation focused on propanotrophic bacteria given their pivotal roles in dioxane metabolism and …

Chemoenzymatic Study Of Coa-Linked Rna In Bacteria, Krishna Sapkota

Dissertations

The ability of RNA to store genetic information and to catalyze biochemical transformations led to the speculation of the existence of RNA world before the evolution of contemporary ribonucleoprotein (RNP) world. Recent discovery of RNA molecules containing metabolic cofactors including coenzyme A and its various thioesters at their 5’ end further supported the RNA world hypothesis as these CoA-linked RNA molecules could be the molecular fossils with very ancient origin. As both RNA and Coenzyme A are believed to have co-existed since last universal common ancestor (LUCA) or even before, the CoA-RNA conjugates in current biology may reveal fundamental molecular …

Engineering Of Escherichia Coli 2-Oxoglutarate Dehydrogenase Complex With Mechanistic And Synthetic Goals, Joydeep Chakraborty

Dissertations

The Escherichia coli 2-oxoglutarate dehydrogenase complex (OGDHc) compromises multiple copies of three enzymes - 2-oxoglutarate dehydrogenase (E1o), dihydrolipoyl succinyltransferase (E2o), and dihydrolipoyl dehydrogenase (E3). OGDHc is found in the Krebs cycle and catalyzes the formation of the all-important succinyl-Coenzyme A (succinyl-CoA). OGDHc was engineered to understand the catalytic mechanism and optimized for chemical synthetic goals.

Succinyl-CoA formation takes place within the catalytic domain of E2o via a transesterification reaction. The succinyl group from the thiol ester of S8-succinyldihydrolipoyl-E2o is transferred to the thiol group of CoA. Mechanistic studies were designed to investigate enzymatic transthioesterification. His375 and Asp374 was shown to …

Peroxisomal Protein Defects Disrupt Coordinated Peroxisomal Processes And Affect Early Seedling Development Through Accumulating Toxic Catabolic Intermediates, Ying Li

Dissertations

Many peroxisomal proteins act in β-oxidation processes on a range of substrates. It is unclear how these proteins are coordinated to determine the flux of peroxisomal processes and meet the requirements for plant growth and development. Using mutant analysis and metabolic profiling, I examined proteins predicted to act in fatty acid and indole-butyric-acid (IBA) β-oxidation. ECH2 confers enoyl-CoA hydratase activity for the auxiliary β-oxidation of fatty acids with an even cis-unsaturated bond. ECH2 was suggested to function in IBA β-oxidation, as ech2 seedlings have altered IBA response. ech2 seedlings have reduced root length and cotyledon area. ech2 seedlings accumulate 3-hydroxyoctenoate …

Puf Proteins: Regulation Of Condition-Specific Mrna Decay And Contributions To Ribosome Biogenesis In Yeast, Anthony Fischer

Dissertations

Regulation of protein expression is critical to organism survival. Multiple disease states arise from aberrant accumulation/aggregation of proteins or reduced production of key enzymes. Cells have many ways to manipulate protein levels, including transcription factors, chromatin modification, modification of messenger RNA (mRNA), and manipulation of proteolytic protein decay. Cells can indirectly control protein volume by controlling mRNA lifespan, which is directly correlated with protein output. Often, sequence-specific elements in mRNA contribute to this lifespan. The Puf family of RNA-binding proteins is ubiquitous throughout eukarya, and plays important cellular and developmental roles through mRNA lifespan regulation. Puf proteins contain a C-terminal …

The Characterization Of The Transcription Factor Msab And Its Role In Staphylococcal Virulence, Justin Batte

Dissertations

Staphylococcus aureus is a common human pathogen that is responsible for a wide range of infections, ranging from relative minor skin infections to life-threatening disease such as bacteremia, septicemia, and endocarditis. S. aureus possesses many different virulent factors that aid in its ability to cause this wide array of infections. One major virulence factor includes the production of capsular polysaccharide (CP). The production of CP plays a major role in the virulence response during infection specifically by providing S. aureus an antiphagocytic mechanism that allows the pathogen to evade phagocytosis during an infection. S. aureus has developed complex genetic regulatory …