Biochemistry, Biophysics, and Structural Biology Commons^™

The Rpm-1/Phr Signaling Hub Modulates Tau-Induced Neurodegeneration Through Regulation Of Microtubule Stability And Mapk Pathways In C. Elegans, Xinxing Ding

Theses and Dissertations

Neurodegenerative diseases, including Alzheimer's disease and frontotemporal dementia, are characterized by the accumulation of pathological tau proteins and progressive neuronal loss. Although research regarding tau-mediated toxicity is extensive, the specific pathology that determine whether neurons maintain homeostasis or succumb to collapse under tau-induced stress remain incompletely elucidated. A central, yet still insufficiently understood, feature of these diseases is the disruption of the microtubule (MT) cytoskeleton . The PHR protein family is evolutionarily highly conserved; within this family, RPM-1 in C. elegans functions as an intracellular signaling hub that regulates axon development, synapse formation, axon termination, and various microtubule-associated processes. This …

A Rho5-Cnc1-Dnm1 Signalling Module Coordinates Multi-Organelle Execution Of Regulated Cell Death In Yeast, Justin Bauer

Theses and Dissertations

Regulated cell death is a conserved process with major implications for health and disease, yet how yeast cells integrate stress signals to determine survival versus death remains unclear. This thesis investigates Cyclin C (Cnc1), a conserved Mediator kinase module component with both transcriptional and mitochondrial roles. Together with Cdk8 Cnc1 primarily represses stress response genes, while upon stress it translocates to the mitochondria to induce mitochondrial fragmentation with the dynamin-related GTPase Dnm1. Using structure-guided separation-of-function mutants, I demonstrate that Cnc1-dependent death requires its mitochondrial function rather than its transcriptional role, and that its effector Dnm1 acts as a signaling node …

Phenotypic Contribution And Regulation Of Vibrio Parahaemolyticus Cold-Shock Protein Homologue Vp1889, Oleg Borisovich Ermolinsky

Theses and Dissertations

Vibrio parahaemolyticus is the primary causative agent of a form of gastroenteritis called vibriosis commonly acquired from ingestion of raw and undercooked seafood. The primary mitigation of seafood-borne illnesses is immediate storage on ice following catch, which inhibits bacterial metabolism and replication. Mesophilic bacteria such as V. parahaemolyticus induce expression of cold-shock proteins in a process named the cold shock response, which facilitates survival at low temperatures. V. parahaemolyticus bears 3 homologues of the major Escherichia coli cold-shock protein CspA, an RNA chaperone. Induction of E. coli CspA at low temperatures depends on autogenous modulation by its mRNA structure, which …

Ethanol State-Dependent Learning In The Honey Bee (Apis Mellifera), Ethan Neil Govea

Theses and Dissertations

Ethanol disrupts neural circuits involved in addiction and withdrawal, yet the molecular mechanisms underlying these effects remain poorly understood. One possibility is that ethanol alters an animal’s perceptual or internal state, causing a stimulus learned while intoxicated to be processed differently when the animal is sober. This study examined how ethanol exposure affects odor learning, recall, and discrimination in honey bees, a useful model because of their robust olfactory learning and experimentally accessible neural systems. Bees were differentially conditioned with appetitive reward (sucrose) during hexanol exposure and aversive stimulus (quinine) during decanol exposure. To assess olfactory processing and state dependency, …

Identification Of Peptides For A Muc13 Cancer Vaccine, Abigail Olivia Gomez

Theses and Dissertations

Mucin 13 (MUC13) is a transmembrane glycoprotein that is frequently overexpressed in epithelial cancers. Its extracellular domains and cytoplasmic signaling potential contribute to disrupted cell adhesion, increased invasion, and cancer-promoting pathways, making MUC13 a promising target for immunotherapy. This project used an in-silico approach to identify MUC13-derived peptides predicted to bind HLA class I molecules and support CD8+ T cell-mediated immune responses. Bioinformatics tools were used to screen candidate epitopes for HLA binding affinity, antigenicity, toxicity, IFN-γ-inducing potential, and population coverage, allowing rational prioritization of peptide candidates for experimentation. Selected peptides were evaluated in THP-1-derived macrophages using RT-PCR, Western blotting, …

Biophysical Insights Into A Cryptic, Hydrophobic Binding Site On Pcna, Alexis Dispensa

Theses and Dissertations

Proteins are dynamic molecules whose functional landscapes extend beyond static structural representations. Transient cryptic pockets (buried cavities that emerge through protein motion) represent underexplored targets for allosteric regulation and drug discovery. General anesthetics are small, lipophilic, weakly polar molecules that are well suited to partition into such hydrophobic sites. In this work, environment-sensitive fluorescence, photoaffinity labeling, mass spectrometry, mutational analysis, and microsecond molecular dynamics simulations were integrated to discover and characterize a cryptic, highly apolar binding site within the hydrophobic core of human proliferating cell nuclear antigen (PCNA), a central scaffold in DNA replication and repair. Using the solvatochromic fluorescent …

The Role Of Emerin In Myogenic Differentiation, Nicholas Marano

Theses and Dissertations

The nucleus harbors genetic material encapsulated by the nuclear envelope which is composed of an inner and outer nuclear membrane. The establishment and organization of chromatin at the INM is essential for cell fate during the differentiation program. Integral INM proteins are responsible for chromatin organization at the nuclear envelope. Emerin is a highly conserved type II integral INM protein with roles in chromatin organization, cell signaling, and nuclear structure. Mutations in the emerin gene cause Emery Dreifuss Muscular Dystrophy 1 (EDMD1). Emerin is ubiquitously expressed, but loss of emerin function affects specifically skeletal muscle and cardiac tissue. The precise …

Structural Characterization Of Peptide Nanoaggregates At Varying Concentrations And Their Impact On Cellular Responses, Malika Rozmetova

Theses and Dissertations

Peptide nano-assemblies can regulate cellular pathways in a structure-dependent manner. Here, we show that the enzyme-responsive peptide NapFFK(NBD)Yp forms distinct nanoscale assemblies at different concentrations, triggering differential ER stress and extracellular vesicle release in MDA-MB231 cells. These results highlight the importance of supramolecular organization in peptide–cell interactions.

Absolute Quantification And Identification Of Rna From Rna-Lipid Nanoparticles Using High Resolution Mass Spectrometry, Jason C. Funderburk

Theses and Dissertations

RNA therapeutics are a rising drug category with potential use for a range of conditions encompassing infectious diseases to therapies for cancer, diseases, and genetic disorders. RNA-lipid nanoparticles (RNA-LNPs) are the prominent delivery method for these therapeutics approved products include mRNA vaccines and polyneuropathy treatments. The emergency use authorizations and orphan drug status of current RNA-LNP drugs has allowed approval without finalization of the regulatory analytical procedures for quality monitoring. The objective of the study was to develop an LC-MS assay to simultaneously measure identity and concentration of two therapeutically relevant intact RNA constructs extracted from RNA-LNPs to enhance quality …

Exploring The Growth Dynamics Of Streptococcus Mutans In Diverse Environmental Conditions, Vanessa Escudero

Theses and Dissertations

Dental caries, a prevalent oral health issue, is primarily associated with the growth of Streptococcus mutans, a Gram-positive bacterium that grows under various oral environments. The primary objective of this study was to evaluate the impact of different beverages and mechanical cleaning on the growth of S. mutans, which plays a crucial role in tooth decay. Using a nano-spectrophotometer we analyzed bacterial growth by constructing growth curves under different conditions, including exposure to cranberry juice, Hawaiian juice, and mechanical brushing.

The study was designed to mimic real-world oral conditions by testing S. mutans in four distinct environments. First, we established …

Bacillus Subtilis: A Bacterium That Can Potentially Degrade Low-Density Polyethylene (Ldpe) And Polyethylene Terephthalate (Pet), Migdalia Flores

Theses and Dissertations

The widespread application and disposal of plastics, such as low-density polyethylene (LDPE) and polyethylene terephthalate (PET), have raised significant environmental health concerns. Because of each plastic’s stability and durability, these plastics exhibit limited natural degradation in the environment. Recently, the environmentally friendly biodegradation of plastics by living microorganisms has attracted more attention, as they can assist in the natural degradation process. In this study, the bacterial strain Bacillus subtilis ATCC6051 was used to degrade LDPE and PET for 60 days. To measure the degradation of low-density (LDPE) and polyethylene terephthalate (PET), the dry weight was taken, and physical characteristics were …

3d Bioprinting On Electrospun Nanofibrous Scaffolds To Fabricate Myocardial Patches, Muthu Parkkavi S

Theses and Dissertations

Tissue-engineered three-dimensional (3D) myocardial patches offer superior and innovative treatment strategy for myocardial infarction (MI). Among the various scaffold fabrication techniques, electrospinning and 3D bioprinting have received great attention due to their ability to recreate native cardiac tissue mimetic characteristics. Despite several advantages, electrospun nanofibers have limitations in cell delivery due to random cell seeding, while bioprinting faces challenges in creating hydrogel constructs with ideal mechanical properties capable of supporting cardiac contraction/relaxation cycle. Hence in this work, hybrid myocardial patches were developed by converging electrospinning and bioprinting techniques.

Electrospinning of PLCL:PEOz (B73, 7:3 blend of poly-L-lactide-co-ε-caprolactone (PLCL) and polyethyl oxazoline …

Effect Of Osmolytes On The Interplay Of Water Protein And Dna In Ecori Dna Recognition Using Molecular Dynamics Simulations, Aathithya D

Theses and Dissertations

EcoRI is a type II restriction endonuclease that has been widely used as a model system to study protein-DNA interaction owing to its high degree of specificity. This enzyme does not recognize even a single basepair change in its recognition sequence, (GAATTC)2, under normal conditions. However, in the presence of osmolytes, such as glycerol and DMSO, the specificity of EcoRI is slightly relaxed and recognizes sequences that differ from its cognate sequence in the first basepair position. This relaxed specificity has been attributed to the dehydration of the EcoRI-DNA which presumably results in tighter complex formation and subsequent catalysis. However, …

Acute Exposure Of American Oyster (Crassostrea Virginica) To Selected Antidepressant Drug: Histological, Biochemical, And Immunohistochemical Assessments, Md. Faisal Amin

Theses and Dissertations

The rapid increase in pharmaceutical use has brought significant health benefits to humans. Studies have shown that many pharmaceuticals, such as antidepressants, are often detected in surface waters, groundwater, and even drinking water. These pharmaceuticals in aquatic environments threaten marine life seriously. Marine bivalves are vital source of seafood for people worldwide. In this study, we examined the effects of short-term exposure to fluoxetine, an antidepressant used to treat depression, at low (0.5 μg/L) and high (5 μg/L) doses over a one-week period on American oysters (Crassostrea virginica) under controlled laboratory conditions. Histological analysis revealed atrophy in the gills and …

Biological, Histological, And Immunohistochemical Responses To Heat Stress In Common Goldfish, Carassius Auratus, Ngozichukwu Francis Ngozichukwu

Theses and Dissertations

Global climate change has led to rising temperatures, posing significant challenges to aquatic ecosystems and the health of ectothermic species such as goldfish (Carassius auratus) This thesis investigated the effects of heat stress on growth performance, histological alterations, and molecular stress responses in the gill and kidney tissues of goldfish Fish were exposed to control (24°C), medium (28°C), and high (32°C) temperatures for two weeks Growth parameters, including instantaneous growth rate (IGR), absolute growth rate (AGR), body value gain (BVG), and condition factor, were evaluated alongside histological and immunohistochemical markers of stress Results revealed that high temperature significantly reduced AGR …

Analyzing How Taste And Nutrition Impact Learning And Memory In Honey Bees Through Olfactory Associative Conditioning, Alessandra Elizabeth Perry

Theses and Dissertations

Honey bees detect sweet nectar, but not all sweet-tasting sugars provide nutrition. Unlike fruit flies, which can learn to avoid non-nutritious sweet foods, bees may lack this ability. To test if bees form caloric frustration memory (CFM), we conditioned them using odors paired with L-glucose (sweet but non-nutritious) or D-glucose (sweet and nutritious). Bees rewarded with L-glucose showed lower learning and long-term memory compared to D-glucose. Bees cannot differentiate between an odor associated with rewards containing malaise-causing compounds and an odor associated with a reward alone during differential conditioning. Therefore, we used differential conditioning to determine if lower acquisition in …

Transcriptomic Study On The Effect Of Salt Stress In Sorghum Bicolor Seedlings, Joshwa A. Gandy

Theses and Dissertations

The global impact and reliance on cereal crops, and sorghum in particular, is paramount for worldwide food security and for the livelihood of hundreds of millions of people. The detrimental effects of salt stress on crop plants and the huge economic losses it causes by affecting agricultural output worldwide is a devastating issue with huge impacts, which have prompted research to combat salinity in numerous ways. Understanding how cereals respond to the negative effects of salt stress is crucial for enhancing their salt tolerance. In this study of sorghum, we used a 3’-end RNA sequencing approach to elucidate major salt …

Molecular And Clinical Insights Into Role Of Gper In Hepatocellular Carcinoma (Hcc), Hossain Ahmed

Theses and Dissertations

Metabolic dysfunction–associated steatotic liver disease (MASLD), encompassing stages from steatosis (MASLD) to steatohepatitis (MASH), cirrhosis, and hepatocellular carcinoma (HCC), is the most prevalent chronic liver disease worldwide, yet molecular markers of progression remain limited. The G protein–coupled estrogen receptor (GPER), a non-genomic estrogen receptor with metabolic and anti-inflammatory roles, emerges as a candidate regulator in hepatic pathophysiology. In this Dissertation thesis, we have delineated for the first time clinicopathological assessment of liver biopsies across MASLD stages revealing a robust inverse correlation between GPER expression and disease severity. Higher GPER levels in early MASLD associated with favorable metabolic and biochemical profiles, …

Cytidine Triphosphate Specifically Modulates Parb-Mediated Dna Compaction: Insights From Single-Molecule Analysis And Parb C-Terminal Lysine Mutagenesis, Lois Akosua Serwaa

Theses and Dissertations

ParB is a central player in bacterial chromosome segregation, and cytidine triphosphate (CTP) is known to modulate its DNA compaction activity. This study explored whether CTP’s regulatory effect is due to specific molecular interactions beyond its known CTP-binding pocket. Using single-molecule flow-stretching and TIRF microscopy, we showed that CTP significantly reduces DNA compaction by wild-type Bacillus subtilis ParB, while ATP has no effect, supporting the hypothesis that CTP acts through specific recognition rather than general charge. CTP’s modulatory effect persisted across C-terminal domain (CTD) lysine mutants. Compaction was reduced in wild-type and K255A but abolished in K252A and K259A. The …

Oxytocin As A Possible Vegf Inhibitor For Treatment Of Diabetic Retinopathy, Daira Yepez

Theses and Dissertations

Diabetic retinopathy (DR) is a major complication of diabetes and a leading cause of vision loss largely driven by the overexpression of vascular endothelial growth factor (VEGF), which promotes neovascularization and vascular permeability in the retina. Current treatments, primarily anti-VEGF injections, inhibit the effects of VEGF once it has been secreted but can be ineffective in a certain subset of patients. Recent studies suggest that oxytocin (OXT), a neuropeptide mainly known for its roles in reproduction and social bonding, may downregulate VEGF expression. This study aimed to investigate whether OXT influences VEGF secretion in the human retinal pigment epithelial (RPE) …

Investigating The Role Of Metallothioneins In Fungal Iron Homeostasis, David Eap

Theses and Dissertations

The pathogenic fungi Aspergillus fumigatus requires metals to survive and infect humans, but metal overload can be detrimental. Metallothioneins (MTs) are small, cysteine-rich proteins that alleviate metal toxicity by binding excess metals (typically Zn or Cu) for storage or delivery. A recent report indicates that the Fe-S cluster binding glutaredoxin GrxD and the putative Cu-MT CmtA were interacting under high iron conditions in A. fumigatus. We hypothesize that this MT may have a role in binding iron or Fe-S clusters under iron overload conditions to prevent iron toxicity. We also aim to characterize this new MT by determining its …

From Differentiation To Disease: Cyclin C Directly Coordinates Transcription And Mitochondrial Dynamics, Alicia Campbell

Theses and Dissertations

Organelle crosstalk is essential for coordinating cellular responses to various external cues, including stress and differentiation. Two key organelles, the nucleus and mitochondria, engage in extensive crosstalk to manage responses to a range of environmental and developmental signals. Complex processes such as stem cell differentiation and neuronal development rely on organelle crosstalk. Both processes integrate changes in gene expression with cytosolic and organellar remodeling. However, it remains unclear how these two complex processes are coordinated to achieve the desired outcome. This project concentrates on cyclin C (CCNC), a component of the Mediator Kinase Module (MKM), and its role in directly …

The Effects Of Ataxin-1 Overexpression In The Central Nervous System On Specific Behavioral And Physiological Characteristics Of Drosophila Melanogaster, Sydney Davis

Theses and Dissertations

Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disease caused by a CAG repeat expansion in the ataxin-1 gene, which results in an abnormally long polyglutamine tract. Similarly, overexpression of wildtype Ataxin-1 (wt-Atx-1) in Drosophila melanogaster leads to neurodegeneration, reduced lifespan, and impaired negative geotaxis. Observations include disruptions in sleep-wake cycles, increased oxidative stress biomarkers (like protein carbonyls), and dysregulation of developmental genes such as armadillo (arm) and nemo kinase (nmo). Additionally, elevated expression of SUMOylation-related genes (Aos-1, Uba2, and dSmt3 or dSumo) and increased SUMO protein levels indicate enhanced SUMOylation in the brain. Quantitative analysis of neuronal …

Exploring Sexual Dimorphism In A Drosophila Melanogaster Model Of Spinocerebellar Ataxia Type 1, Madelyn Hunter

Theses and Dissertations

Neurodegenerative diseases affect over 36 million people and are characterized by loss of motor control, neuronal degradation, and behavioral changes. The most common of these diseases exhibit sexually dimorphic effects. In this study, Spinocerebellar ataxia type 1 (SCA1) was modeled in the Drosophila central nervous system using the yeast hybrid UAS/GAL4 system. Locomotor activity and clock gene expression was monitored for male and female SCA1 and control flies. Clock genes such as per, tim, Clk, and cyc were monitored over a 24-hour period using qRT-PCR, and distinct sexual dimorphism was detected in locomotor activity and in gene expression for SCA1 …

Developing A Small Molecule To Inhibit Hsf1 Expression In Cancer And Evaluating Natural Genetic Variation In Small Molecule Toxicity., Michaela Kendal Foley

Theses and Dissertations

Each year cancer affects nearly 20 million people worldwide and genetic differences across populations can impact cancer onset and progression. Specifically, tumors with high levels of HSF1, the master regulator of the cytoprotective heat shock response (HSR), are correlated with poor patient outcomes in multiple cancers such as prostate, breast, and melanoma. Subsequently, the development of pharmacological inhibitors of HSF1 represents a promising strategy for anticancer therapeutics. Using a luciferase-based transcriptional reporter, two small molecule libraries were screened for inhibitors of HSF1 expression in human embryonic kidney cells, yielding ten compounds that decrease HSF1 expression. To identify if cancer lines …

Identification Of Cadmium As A Structural And Functional Modulator Of Psd-95 Regulating Nmdars At Postsynaptic Membranes, Claudia Garza

Theses and Dissertations

Postsynaptic density-95 (PSD-95) is an essential scaffolding protein in excitatory neurons. PSD-95’s N-terminal palmitoylation region elicits synaptic plasticity by targeting, anchoring, and trafficking glutamate receptors, such as N-methyl-d-aspartate receptors (NMDAR), to the postsynaptic membrane. The molecular interactions of PSD-95 and its dysregulation in excitatory synapses are currently being explored as primary causes of neurodegenerative diseases and disorders, such as Alzheimer’s disease, Schizophrenia, and Parkinson’s disease. Recent studies demonstrate an overaccumulation of zinc at two cysteines (C3 and C5) and two histidines (H24 and H28) of PSD-95 blocks palmitoylation, causing a loss of NMDAR at the postsynaptic membrane. In addition, exposure …

Cloning And Heterologous Expression Of Human Nachrs And A Unique Spider Venom Toxin, Christine M. Vega

Theses and Dissertations

Drug development research has long focused on synthesizing novel therapeutics while overlooking isolation from naturally available sources. Recently, the discovery of the therapeutic effects of highly bioavailable animal venom caused the field of venom research to soar in popularity. Animal venom serves as a natural, sophisticated tool optimized over millions of years by evolution with the ability to bind to ion channels such as nAChRs, non-specific ligand-gated ion channels distributed throughout the human nervous system, with high selectivity and specificity. However, purifying individual venom toxins from crude venom is challenging due to its availability. Therefore, synthesizing large quantities of venom …

Transcription Factor Y- Box Binding Protein 1 (Ybx1) Enhances Sorafenib Resistance And Tumorigenic Capacities In Hepatocellular Carcinoma (Hcc), Dennis Kwabiah

Theses and Dissertations

Hepatocellular carcinoma (HCC) is the most common liver cancer, with early-stage cases potentially benefiting from surgical treatments like liver transplantation and hepatectomy. However, advanced HCC stages have poor prognosis due to resistance to therapies, especially sorafenib, a tyrosine kinase inhibitor approved for late-stage HCC. Despite its clinical use, sorafenib has limited efficacy in prolonging survival, and the mechanisms of resistance remain unclear. Analysis of The Cancer Genome Atlas (TCGA) HCC dataset shows elevated Y-box binding protein 1 (YBX1) expression in HCC tumors compared to normal liver tissues. Previous studies have indicated that YBX1 is involved in drug resistance in various …

Inhibition Of Lysine Deacetylase Activity Impacts Formation Of The Vitamin D Receptor Activation Complex, Shannon Dwyer

Theses and Dissertations

The vitamin D endocrine system is responsible for the regulation of many biological processes including bone metabolism, calcium homeostasis, cell proliferation and cell differentiation. Alterations to the vitamin D signaling pathway are associated with several diseases including bone diseases, diabetes, cardiovascular diseases, autoimmune diseases, and cancer. Vitamin D precursors are chemically modified to become the biologically active hormone, calcitriol. Calcitriol binds to the vitamin D receptor (VDR), a member of the nuclear hormone receptor (NHR) superfamily. VDR forms a heterodimer with retinoid X receptor (RXR) and together they bind to promoters containing vitamin D response elements (VDREs) to activate transcription …

Optimizing Biofilm Assay Reproducibility And Characterizing The 12-Hydroxystearic Acid On Escherichia Coli, Khilola Khusanova

Theses and Dissertations

Biofilm formation in Escherichia coli plays a critical role in microbial chemical communication and surface-associated persistence. This study investigates the antibiofilm activity of 12-hydroxystearic acid (12-HSA), evaluating its R and S enantiomers as well as a racemic mixture. E. coli BL21, biofilms were grown under standardized laboratory conditions and quantified using the Crystal Violet staining assay. Treatment with 12-HSA resulted in a measurable reduction in biofilm biomass, with differences observed between the individual enantiomers and the mixture. These findings suggest that 12-HSA influences early adhesion and biofilm development, supporting its potential as a small-molecule modulator of bacterial surface behavior. This …