Biochemistry, Biophysics, and Structural Biology Commons^™

Tools To Evaluate Nanodiamond-Mediated Delivery Of Tiopronin For Cataract Prevention, Justin Beltz

Doctoral Dissertations

”There is a growing demand for non-surgical means of cataract treatment. This dissertation presents three bodies of work that reflect the early-stage development of eye drop formulations aimed at delaying cataract progression. These formulations consist of the antioxidant 2-mercaptopropionylglycine (MPG) loaded onto nanodiamond particles.

Cataractogenesis is linked to oxidative damage to lens proteins. To investigate the potential of MPG for protection against oxidative damage, A549 cells were incubated in 0.6 mM tert-butylhydroperoxide (tBHP). Cells exposed to tBHP without MPG exhibited elevated levels of reactive oxygen species, which led to the depletion of the vital antioxidant glutathione and, ultimately, apoptosis. Co-administration …

Structural Basis For The Stereoselective Epoxidation Reaction In Polyether Natural Product Biosynthesis, Qian Wang

Open Access Theses & Dissertations

Polycyclic polyether natural products have received much attention due to their diverse biological activities, ranging from extreme toxicity to therapeutic properties, including antimicrobial, antifungal, and anticancer activities. They are featured by multiple cyclic ether groups that vary in the number, size, and arrangement. Ionophore polyethers contain multiple tetrahydrofuran and tetrahydropyran rings connected by either spiroketal systems or carbon-carbon single bonds. Over the past 40 years, significant progress has been made in deciphering polyether biosynThesis pathways. Remarkably, all members of the polycyclic polyether family are thought to be generated via a common biosynthetic scheme. In 1983, Cane, Celmer, and Westly proposed …

Outlier Profiles Of Atomic Structures Derived From X-Ray Crystallography And From Cryo-Electron Microscopy, Lin Chen, Jing He, Angelo Facchiano

Computer Science Faculty Publications

Background: As more protein atomic structures are determined from cryo-electron microscopy (cryo-EM) density maps, validation of such structures is an important task. Methods: We applied a histogram-based outlier score (HBOS) to six sets of cryo-EM atomic structures and five sets of X-ray atomic structures, including one derived from X-ray data with better than 1.5 Å resolution. Cryo-EM data sets contain structures released by December 2016 and those released between 2017 and 2019, derived from resolution ranges 0–4 Å and 4–6 Å respectively. Results: The distribution of HBOS values in five sets of X-ray structures show that HBOS is sensitive distinguishing …

Antioxidant Intervention In Radical-Induced Protein Damage, Emmanuel Zubia

Open Access Theses & Dissertations

Many environmental toxicants are known to increase free-radical production, which can create cellular havoc and lead to a myriad of ailments. Antioxidants can be used to ameliorate the prevalence of free radicals, potentially serving as prophylactics against radical-induced disorders. Many exogenous antioxidants are phytochemicals in origin, such as ascorbic acid, gallic acid, and ellagic acid. Some of these antioxidants can be found in traditional medicine, like tanshinone and brazilin, which have been studied and are known to have low cytotoxicity. Here we test the radical rescue capacity of a selected group of phytochemical antioxidants on protein rescue models. Specifically, our …

Insights Into The Structure, Pharmacology, And Evolution Of The Glycine Transporter 2, Ashley Bryan Lopez

Open Access Theses & Dissertations

The balance between neuronal excitation and inhibition in the central nervous system is vital for survival. Overexcitation can be toxic and lead to certain manias or even death. On the other hand, extremely low levels of inhibition cause hyperekplexia, pain, and even forms of autism. Neuronal inhibition is, for the most part, achieved by two neurotransmitters, GABA and glycine. Levels of both neurotransmitters in the synaptic cleft are meticulously regulated by the GABA and glycine transporters, respectively, which belong to the solute carrier 6 (SLC6) family of neurotransmitter transporters and share structural similarities with other family members. In Chapter 1, …

Molecular And Functional Characterization Of Α-Galactosyl Epitopes In Trypanosoma Cruzi, Uriel Ortega Rodriguez

Open Access Theses & Dissertations

Trypanosoma cruzi, the causative agent of Chagas disease (CD) currently affects 6-7 million people across the world. Currently, only two drugs, benznidazole and nifurtimox, are available for treatment of CD and they are highly toxic and less effective in the chronic stage of the disease. Specific biomarkers for diagnosis and follow-up of treatment do not exist in the clinical settings. following chemotherapy, patients take approximately 10-20 years to exhibit negative seroconversion with the conventional serology assays. Moreover, there is no vaccine available to prevent or treat CD. T. cruzi contains a complex cell surface consisting of several classes of glycoconjugates …

A Role For Mek3 In The Oncogenesis Of Acute Lymphocytic Leukemia: Inactivation Of Mapk P38 Promotes Cell Proliferation Through Enhanced Degradation Of Mutant Mek3, Yoshira Marie Ayala-Marin

Open Access Theses & Dissertations

In the United States, pediatric leukemia has the second-highest cancer mortality rate in Hispanic children, especially Acute Lymphocytic Leukemia (ALL). While treatment of ALL has improved overall the five-year survival rate of ~90 %, not everyone has benefited. Twenty percent of them will experience relapse, and from these, 30 - 50 % will die. Unfortunately, the cause behind these dreadful statistics is poorly understood due to the complex etiology of this disease. Thereby, it is essential to identify potential oncogenic proteins that promote ALL so that new strategies can be developed to diagnose and treat this cancer. Whole Exome Sequencing …

Selectivity For Allosteric Effectors Of Bacterial Adp-Glucose Pyrophosphorylase: Structural And Functional Studies, Mashael Alghamdi

Dissertations

The biosynthesis of the intracellular polysaccharide in bacteria and plants, glycogen and starch, respectively, controlled by the key regulatory step that catalyzed by ADP-Glucose Pyrophosphorylase (ADP-Glc PPase). ADP-Glc PPase is an allosteric enzyme regulated by metabolites produced of the principle carbon assimilation pathway in each organism. Agrobacterium tumefaciens enzyme activated by fructose 6-phosphate (Fru6P) and pyruvate, whereas Escherichia coli enzyme activated by fructose 1,6-bisphosphate (FBP), and both enzymes inhibited by AMP. Here, we targeted the allosteric regulation of the A. tumefaciens enzyme, examined some residues that may impact the regulation mechanism (Ser72, His71, Arg75, Ser351, Ser334, Arg368, Asn350, and Asp291), …

Human Isocitrate Dehydrogenase Enzymes, Joseph Valentein Roman

Dissertations

Mammals have three forms of isocitrate dehydrogenase (ICDH) that each catalyze the oxidative decarboxylation of isocitrate forming alpha-ketoglutarate (AKG), carbon dioxide and reduced pyridine nucleotide. The intra-mitochondrial, citric acid cycle enzyme is ICDH III that exists as a hetero tetramer and uses NAD+ as a substrate. ICDH I and ICDH II are both dimeric enzymes that reside in the cytosol and use NADP+. While, the precise function of the cytosolic ICDHs is not known, active site variants of both ICDH I and II cause a variety of cancers. The R132H variant of ICDH1 is one of the most common alterations. …

Controlled Release Of Fibroin Repeat-Tagged Proteins From Silk Hydrogel, Jaturong Promsuk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Protein-based biologic drugs such as growth factors are playing important roles in modern medicine. These proteins can be used to stimulate local tissue repair. Growth factors are often incorporated into a scaffold, such as a hydrogel, and then put into the desired area of the body to achieve therapeutic effects. However, diffusion of these growth factors outside of the designated area or inappropriate release time can have deleterious consequences, such as inducing tumors in other areas of the body or uncontrolled inflammation. Therefore, this project aims to create a model to study diffusion of protein from hydrogel by using green …

Roles Of Bacterial Toxin Receptor And Piwi-Interacting Rna Of Pacific White Shrimp Penaeus Vannamei In Response To Vibrio Parahaemolyticus-Causing Acute Hepatopancreatic Necrosis Disease Infection, Waruntorn Luangtrakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Acute hepatopancreatic necrosis disease (AHPND) or Early mortality syndrome (EMS) caused by virulent strains of Vibrio parahaemolyticus AHPND (VPAHPND) has been a leading cause of significant losses of shrimp production. In this study, we aim to explore the response and the role of immune-related gene/protein and small RNA in the VPAHPND-infected shrimp. This research was divided into 2 parts. In the first part, we identified candidate genes of VPAHPND toxin receptor and further confirmed its function as a VPAHPND toxin receptor. APN has been reported as a Cry toxin from Bacillus thuringiensis, whose structure is similar to VPAHPND toxin. Therefore, …

Metabolite Profiling And Gene Expression Analysis In Starch And Sugar Metabolisms Of Ripening Durian Durio Zibethinus Pulp, Lalida Sangpong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Durian (Durio zibethinus L.), an economically important fruit of Southeast Asian countries, expresses unique flavor at the edible ripe stage, resulting from metabolic changes during the ripening process. Nevertheless, the study in such modulations is still limited. In the first manuscript, we profiled metabolites from unripe and ripe pulps of durian cv. Monthong using capillary electrophoresis- (CE) and gas chromatography- (GC) time-of-flight mass spectrometry (TOF/MS) and obtained the total 94 ripening-related metabolites from a combination of the two datasets, of which we focused on flavor-related metabolites. For sugar, sucrose is the most abundant sugar that increased during ripening, and the …

Protective Effects Of Tiger Milk Mushroom (Lignosus Rhinocerus) Extracts On Oxidative Stress-Induced Neurotoxicity And Aging In Ht22 Cells And C. Elegans, Parinee Kittimongkolsuk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Lignosus rhinocerus (LR) or Tiger Milk Mushroom, a fork medicinal mushroom, has been reported for several pharmacological effects including asthma treatment, anti-inflammatory, anti-proliferative, immuno-modulating effects, promote neurite outgrowth in PC-12 cells, anti-HIV-1 activity, and antioxidants properties. However, the antioxidant properties have only focus on in vitro and no or few studies have reported their protective effects in mouse hippocampal (HT22) cells and Caenorhabditis elegans (C. elegans). This study aims to investigate the neuroprotective effect of three extracts of LR against oxidative stress in both HT22 cells and. C. elegans as well as longevity in C. elegans. In HT22 cells, we …

Generation Of Neural Stem Cells (Nscs) From Human Fibroblasts Using Qq-Modified Sox2 And Neurod1 Proteins, Abdullah Ibrahim Alhomoudi

Wayne State University Theses

The generation of induced neural stem cells (iNSCs) and induced neuronal cells (iNCs) from somatic cells provides new avenues for basic research and potential transplantation therapies for neurological diseases. However, clinical applications must consider the tumor formation capabilities of the implanted cells, the inability of iNCs to self-renew in culture, and reprogramming methods that use retroviral transduction which permanently alter genetic network of the cells. Here we report the generation of protein-induced neural stem cells (piNSCs) from human dermal fibroblasts using QQ-SON pluripotent reprogramming as a tool to quickly reset the time clock of the human somatic fibroblasts to a …

Can The Carbon And Nitrogen Isotope Values Of Offspring Be Used As A Proxy For Their Mother's Diet? Using Foetal Physiology To Interpret Bulk Tissue And Amino Acid Δ15N Values, Nico Lübcker, John P. Whiteman, Seth D. Newsome, Robert P. Millar, P.J. Nico De Bruyn

Biological Sciences Faculty Publications

The measurement of bulk tissue nitrogen (δ¹⁵N) and carbon isotope values (δ¹³C) chronologically along biologically inert tissues sampled from offspring can provide a longitudinal record of their mothers' foraging habits. This study tested the important assumption that mother-offspring stable isotope values are positively and linearly correlated. In addition, any change in the mother-offspring bulk tissues and individual amino acids that occurred during gestation was investigated. Whiskers sampled from southern elephant seal pups (Mirounga leonina) and temporally overlapping whiskers from their mothers were analyzed. This included n = 1895 chronologically subsampled whisker segments for bulk …

Characterization Of The Tsc/Dyrk1a Interaction, Supriya Joshi

Theses and Dissertations

The Tuberous sclerosis complex (TSC) includes TSC1, TSC2 and the TBC1D7 subunits that together function as a principal inhibitor of the mTOR protein kinase complex 1 (mTORC1). mTORC1 is a master regulator of cell growth and proliferation that responds to signaling cues such as growth factors and nutrient availability. Proteomic studies in our lab revealed an interaction between the TSC subunits and DYRK1A, a ubiquitous protein kinase encoded by a gene located in the Down syndrome (DS) region on human chr21. In this study, we sought to validate the interaction of the TSC components with DYRK1A and to determine the …

Characterizing Glycosaminoglycan And Glycosaminoglycan-Oligo Interactions With Cancer Stem Cells And Their Regulators, Rahaman Navaz Gangji

Theses and Dissertations

Tumor metastasis and recurrence account for more than 90% of cancer-associated deaths and are thought to occur due to a small subpopulation of neoplastic cells known as cancer stem cells (CSCs). Because CSCs are resistant to conventional chemotherapy, there is a critical need to develop CSC-targeting agents. Microenvironmental components, especially glycosaminoglycans (GAGs), play a key role in regulating CSC phenotype. GAGs such as heparan sulfate (HS) interact with hundreds of proteins and influence a variety of biological processes including tumor proliferation, angiogenesis, metastasis and stem cell biology.

Recently, the Desai and Patel laboratories have demonstrated that a hexasaccharide form of …

Regulation Of Vascular And Lymphatic Endothelial Barrier Function By Sphingosine-1-Phosphate, Jacqueline Bellaci

Theses and Dissertations

Endothelial cells play an important role in maintaining homeostasis, and disruption of the endothelial barrier have been linked to a number of different pathologies, including cancer metastasis. The vascular endothelial barrier is known to be regulated by a variety of factors, including sphingosine-1-phosphate (S1P), a bioactive lipid metabolite, which has been shown to improve barrier function. However, most studies to date have been focused on the vascular endothelium, and the regulation of the lymphatic endothelial barrier has not been thoroughly investigated. We found that prior to any stimulation the lymphatic endothelial cells (LECs) had a lower trans-endothelial resistance (TER) in …

Structural Features Contributing To Methylenedioxypyrovalerone (Mdpv) Analog Inhibition Of The Human Dopamine Transporter, Zachary R. Spires

Theses and Dissertations

Monoamine transporters (MATs) are transmembrane neurotransmitter sodium symporters consisting of the dopamine, norepinephrine, and serotonin transporters: DAT, NET, and SERT, respectively. Following an action potential and neurotransmitter vesicular release, MAT-mediated reuptake of these neurotransmitters in the presynaptic membrane contributes to the termination of monoaminergic neurotransmission. MATs are the targets of many drugs providing therapeutic benefits or taken recreationally. One of these drugs is methylenedioxypyrovalerone (MDPV), an abused synthetic cathinone that is a high potency uptake inhibitor of the human DAT (hDAT). In contrast, MDPV is a low potency uptake inhibitor of the Drosophila melanogaster dopamine transporter (dDAT). The reasons for …

The Impact Of Aging And Mechanical Injury On Alveolar Epithelial And Macrophage Responses In Acute Lung Injury And Inflammation, Michael S. Valentine

Theses and Dissertations

Patients with severe lung pathologies, such as Acute Respiratory Distress Syndrome (ARDS), often require mechanical ventilation as a clinical intervention; however, this procedure frequently exacerbates the original pulmonary issue and produces an exaggerated inflammatory response that potentially leads to sepsis, multisystem organ failure, and mortality. This acute lung injury (ALI) condition has been termed Ventilator-Induced Lung Injury (VILI). Alveolar overdistension, cyclic atelectasis, and biotrauma are the primary injury mechanisms in VILI that lead to the loss of alveolar barrier integrity and pulmonary inflammation. Stress and strains during mechanical ventilation are believed to initiate alveolar epithelial mechanotransduction signaling mechanisms that contribute …