Molecular 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 …

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 …

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 …

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 …

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, …

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 …

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 …

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 …

Expression And Function Of Floral Symmetry Genes In The Regulation Of Flower Shape In Fedia Graciliflora, Theresa A. Mustacchio

Theses and Dissertations

Shifts between radial symmetry (actinomorphy) and bilateral symmetry (zygomorphy) in flowers have occurred multiple times independently within angiosperms (flowering plants). Evidence across angiosperms indicate the transcription factors RADIALIS (RAD), DIVARICATA (DIV), and CYCLOIDEA (CYC) play a major role in regulating floral symmetry and morphology. The CYC-like genes have been shown to shift their expression dorsally independently in nearly all shifts to bilaterally symmetrical flowers examined. Three core eudicot clades of CYC-like genes have been identified: CYC1, CYC2 and CYC3, with only CYC2 genes being shown to have a role in floral symmetry. We use the non-model plant, Fedia graciliflora (Caprifoliaceae) …

Functional Analysis Of Ligand Binding Domain 2 Of Outer Surface Protein C Of Borreliella Burgdorferi, Gavin Z. Chambers

Theses and Dissertations

Lyme disease, caused by the spirochete Borreliella burgdorferi, is the most common vector-borne infection in North America. A critical determinant of early mammalian infection is outer surface protein C (OspC), a highly variable lipoprotein that is indispensable for spirochete survival but whose precise function remains unresolved. OspC has been proposed to mediate diverse roles, including complement evasion, adhesion, tissue dissemination, and antiphagocytic activity, supporting the view that it is a multifunctional virulence factor. Structural studies have identified two putative ligand-binding domains (LBD1 and LBD2), with LBD2 forming a solvent-exposed crown at the membrane-distal end of the OspC dimer.

To …

Caspases Protect Against Hyperglycemia Induced Necroptosis-Like Cell Death In Brain Endothelial Cells, Aleena S. Mathew

Theses and Dissertations

Acute diabetes characterized by high spikes in blood glucose levels in association with severe hyperglycemia can lead to an increased risk of ischemic stroke in the brain. To better understand high blood glucose levels, hyperglycemia, in the brain we explored its effects on endothelial cells. Endothelial cells line the inner walls of blood vessels and are directly impacted in hyperglycemia. Brain endothelial cells are a major component of the blood brain barrier (BBB) which tightly regulates the brain’s microenvironment. The type of cell death such as apoptosis, caspase dependent, or necroptosis, caspase independent, can exacerbate diabetes associated complications. There is …

Ecological And Pathological Applications Of The Heat Shock Response, Taylor Rae Stanley

Theses and Dissertations

The heat shock response (HSR) is a cytoprotective stress response pathway that regulates cellular proteostasis. The HSR is an evolutionarily conserved pathway that is essential for normal cellular functioning. Here, we explore the broad ecological and pathological impacts of the HSR. In an ecological context, we perform gene level analysis of the transcriptomes of two closely related sunfish. We found that the more invasive bluegill sunfish has gene expansions in two HSR gene families, the HSP70 family and the HSP90 family compared to the redear sunfish. These gene expansions were also observed in several other teleost fish species and were …

Investigation Of Reproductive Inhibition During Chronic Heat Stress In C. Elegans, Macy Makenna Nielander

Theses and Dissertations

Nearly all organisms experience heterogeneity in environmental conditions that can negatively impact fitness. A common adaptive strategy to reduce the impact of this stress is called facultative diapause, where development and reproduction are temporarily arrested to promote survival. Facultative diapause is characterized by three major criteria, the arrest must be (i) induced by an unfavorable environmental condition, (ii) reversible, and (iii) driven by genetically regulated mechanisms. The aim of this thesis was to determine whether chronic heat-induced inhibition of egg laying in Caenorhabditis elegans represents a novel form of facultative diapause. It was found that the inhibition of egg-laying is …

Dissecting The Interplay Of Protein Synthesis And Degradation Pathways In Cellular Adaptation To Stress, Brittany Friedson

Theses and Dissertations

Adaptation to stress requires cells to reprogram transcription, translation, and proteolytic pathways. Although much is known about the response of each program, it remains unclear how they coordinate following stress. My studies in S. cerevisiae identified the Cdk8 kinase module (CKM) of the Mediator complex as a new player in coordinating these processes. It is well established that the CKM consists of four highly conserved proteins (cyclin C, its cognate kinase Cdk8, and two structural proteins Med12 and Med13) and predominantly represses a subset of stress responsive genes in yeast. We demonstrated for the first time that the CKM also …

Developing Coexpression Systems To Introduce Hydroxyproline Into Protein Engineered Collagen Peptides Utilizing Hydroxylase From Acanthamoeba Polyphaga Mimivirus, Jennifer Soldatich

Theses and Dissertations

A major challenge of developing collagen mimetic peptides (CMPs) by bacterial expression is to include hydroxyproline for biomedical applications. Coexpression of Prolyl-4-hydroxylase from A.mimivirus with CMPs was investigated. Additionally, four expression designs were created for potential applications in mammalian cells to utilize their natural ability of proline-hydroxylation by post-translational modification.

Pm2.5 In The Respirable Air A Threat To Heart Health Investigating The Influence On Cardiovascular Performance And Unmasking The Potential Strategies For Cardio Protection, Bhavana Sivakumar

Theses and Dissertations

Air pollution, characterized by the presence of harmful substances in the atmosphere, represents a significant environmental and public health challenge impacting millions worldwide. The World Health Organization (WHO) reports that approximately 90% of the global population resides in regions where air pollution surpasses the recommended thresholds for healthy air quality. Within the realm of air pollution, the composition of particulate matter emerges as a pivotal consideration, particularly regarding PM2.5, comprising minute particles originating from diverse sources such as combustion processes, industrial operations, and natural phenomena like wildfires and dust storms. PM2.5 exhibit a range of chemical and physical attributes contingent …

Assessment Of Tripeptides Self-Assembly & Er Stress On Cell Viability And Exosome Secretion In Mda-Mb231, Azmat Parveen

Theses and Dissertations

This study delves into the effects of tripeptides KYpF and WYpK(NBD) on MDA-MB-231 cells, uncovering KYpF's ability to reduce cell proliferation and exosome secretion in peptide treated cells. Conversely, WYpK(NBD) demonstrated significant toxicity at 10 μM. These insights pave the way for optimizing peptide-based cellular treatments for exosome secretion purposes.

Interleukin 24 Induces Apoptosis Through Glycogen Synthase Kinase-3 Beta Inactivation In Prostate Cancer Cells, Sual J. Lopez, Moira Sauane

Theses and Dissertations

Interleukin 24 (IL-24) is a tumor-suppressing protein currently in clinical trials. IL-24 induces cancer-specific apoptosis by activating endoplasmic reticulum (ER) stress and mitochondria dysfunction. We have previously demonstrated that IL-24 leads to apoptosis in cancer cells by protein kinase A (PKA) activation in human breast cancer cells. To further understand the mechanism by which IL-24 induces apoptosis, I analyzed the role of glycogen synthase kinase-3 (GSK3), a highly conserved and normally active serine/threonine kinase in cancer cells and downstream target of PKA. The work reported here provides direct evidence that GSK3 was inhibited following IL-24 treatment in human prostate cancer …

Decisions, Decisions: Dna Damage Induced Modification Of P53 And The Effect Of Modifications On P53 Differential Binding To The Dna, Savannah Gabrielle Keating

Theses and Dissertations

p53 is the most frequently mutated tumor suppressor protein in cancer. It is highly regulated, most often via post-translational modifications (PTMs). Different pathways and target genes are differentially activated by p53 and there is much left to understand how this occurs. The regulation of p53 at the post-translational level is incredibly important to its DNA damage response, and, therefore, it is understood that PTMs are often involved in the differential activation of pathways by p53. This project aimed to identify some of the types and locations of post-translational modifications on p53 in response to different modes of DNA damage with …

Effect Of Plumbagin On Chemo-Resistant Metastatic Retinoblastoma, John J. Soto

Theses and Dissertations

Retinoblastoma, which is an ocular malignancy, usually results in poor prognoses in pediatric patients worldwide. Retinoblastoma in some events, can develop metastatic phenotypes which can lead to secondary tumor formation, furthering deleterious patient outcomes. It is of paramount importance to identify and research potent novel compounds that can be used to increase the likelihood of remission. Plumbagin (PLB) is a plant-derived, neuroprotective agent, which exhibits significant anticancer activities during in vitro study. PLB has been shown to have a high therapeutic efficacy against chemoresistant sublines as well as their normal counterparts. We attempted to show that the chemoresistant ABCC1 could …

Discovery Of Oligomeric States And Small Molecules That Affect Deacylase Activities Of Human Sirtuin-2 (Sirt2), Jie Yang

Theses and Dissertations

Human sirtuin isoform 2 (SIRT2) is an NAD+-dependent enzyme that removes various acyl modifications from lysine residues. SIRT2 is involved in many biological processes, such as transcription, DNA repair, cell proliferation, and metabolism. Due to its diverse functions, SIRT2 is implicated in various disease states, including cancers and neurodegenerative disorders. This dissertation aimed to understand the regulation of SIRT2’s deacylase activities and to discover small molecule modulators of SIRT2. In this work, we found that SIRT2 dimerized in solution, and the dimerization decreased the deacetylase activities without affecting the defatty-acylase activity of this protein. Dimerized SIRT2 dissociates into monomers upon …

Using Rapid Protein Degradation To Determine The Effect Of Runx1 Loss-Of- Function On Dna Damage Accumulation And Repair., Jackriel Pina Morales

Theses and Dissertations

Germline mutations in RUNX1 are associated with familial platelet disorder with a predisposition to myeloid malignancy (RUNX1-FPDMM), in which patients present with low platelet counts,excessive bleeding and bruising, and an increased risk of Acute Myeloid Leukemia (AML)/Myelodysplastic Syndrome (MDS) development throughout their lifetime. To understand how these loss-of-function mutations in RUNX1 drive predispose to malignancy, it is important to develop a detailed understanding of the molecular basis of RUNX1 function. While RUNX1 is a transcription factor, preliminary data from our group and work from others suggests that RUNX1 also interacts with proteins that are critical for DNA damage …

Pipecolic Acid And Novel Insights Into Cerebral Malaria, Akua E. Mensah

Theses and Dissertations

Cerebral malaria (CM), a severe manifestation of Plasmodium infection, prompts our investigation into the nuanced role of pipecolic acid in its pathophysiology. To unravel the molecular intricacies, we conducted in vitro lysine labeling techniques of mice infected with P. berghei ANKA parasites, and human P. falciparum grown in vitro, aiming to discern the impact of Plasmodium on pipecolic acid production. Previous observations indicated an elevation in pipecolic acid levels correlating with neurological decline in children with CM. In our study, confirming elevated pipecolic acid presence in the plasma and brain tissues of CM patients and the animal model of CM, …

Development And Application Of Environmental Dna (Edna) Techniques To Detect Rough-Footed And Yellow Mud Turtles: A Seasonal Field Study To Detect Turtle Edna, Sakib Tahmid Rishan

Theses and Dissertations

The application of environmental DNA (eDNA) has improved the ability of humans to detect the existence and geographical distribution of aquatic organisms. The present study highlights the development and application of eDNA techniques to detect rough-footed mud turtles and yellow mud turtles in different areas in Texas. Both mud turtle species were successfully detected in lakes/resacas using direct eDNA sampling techniques. Moreover, passive eDNA sampling techniques were conducted using different membrane filters to detect mud turtle species. The findings indicated that only the mixed cellulose esters (MCE) filter membranes effectively identified eDNA of yellow mud turtles in the fall, but …

Molecular Insights Of Paraoxonase 2 In Advanced Glycation End Product Induced Endothelial Dysfunction, Ramya R

Theses and Dissertations

Diabetes mellitus (DM) is a metabolic disorder associated with various vascular complications and affects the function of the endothelial cells. Elevated blood glucose levels accelerate the formation of advanced glycation end products (AGEs) by Amadori rearrangement and bind to their Receptor for the advanced glycation end product (RAGE) and evoke release of key pro-inflammatory cytokine proteins leading to endothelial dysfunction. Paraoxonase 2 (PON2) is an endogenous intracellular enzyme, localised in mitochondria, endoplasmic reticulum (ER), and nuclear membrane with numerous properties, like anti-inflammatory, anti-apoptotic and anti-oxidant.

Our present study aims to ascertain the effect of AGEs on PON2 activity and expression, …

The Role Of The Cdk8 Kinase Module In Maintaining Proteostasis, Stephen Willis

Theses and Dissertations

The underlying etiology of numerous disease states results from perturbations in the maintenance of cellular proteostasis. Carcinogenesis relies on these perturbations to foster uncontrolled cell growth and eventual metastases, while neurodegenerative diseases are a consequence of such perturbations. Control of these processes occurs at numerous molecular levels, commonly starting with transcription. A key transcriptional complex that is involved is the CDK8 Kinase Module (CKM). The CKM is conserved from yeast to man, forming a tetrameric complex consisting of MED12, MED13, CDK8, and CCNC. The CKM has not only been implicated in a variety of cancers but also in a spectrum …