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Modulation Of Bax/Bak Dependent Apoptosis By Sirtuin 3 And Mitochondrial Permeability Transition By Sirtuin 4, Manish Verma

Graduate School of Biomedical Sciences Theses and Dissertations

Mitochondria are dynamic organelles that regulate a myriad of cellular functions, including energy production and metabolic regulation. Mitochondria are also a critical regulator of cell death signaling cascades modulating both apoptotic and necrotic cell death. However, what determines which cell death pathway is activated is still unclear. The mitochondrial/intrinsic pathway of apoptosis is dependent on the activation of pro-apoptotic proteins, Bax and Bak, which induce mitochondrial outer membrane permeabilization (MOMP). Once the integrity of outer mitochondrial membrane (OMM) is compromised, pro-apoptotic intermembrane space proteins like cytochrome c, Smac/Diablo, Omi/HtrA2 and AIF are released into the cytoplasm, which activates the post-mitochondrial …

Med13p Prevents Stress-Independent Mitochondrial Hyperfragmentation And Aberrant Apoptosis Activation In Saccharomyces Cerevisiae By Controlling Cyclin C Nuclear Localization, Svetlana Khakhina

Graduate School of Biomedical Sciences Theses and Dissertations

During aging, and as a result of environmental changes, cells are exposed to elevated levels of reactive oxygen species (ROS). High ROS levels induce lipid oxidation, protein aggregation, mitochondrial hyperfragmentation, DNA damage and programmed cell death (PCD), also called apoptosis. PCD is a highly regulated process and its misregulation has been linked to neurodegenerative diseases and cancer development.

Our hypothesis is that cyclin C plays a role in the initiation of apoptosis. During normal conditions, cyclin C represses the transcription of stress response genes (SRG). In response to stress, cyclin C translocates to the cytoplasm where it facilitates mitochondrial hyperfragmentation …

Effects Of Xanthan/Locust Bean Gum Mixtures On The Physicochemical Properties And Oxidative Stability Of Whey Protein Stabilized Oil-In-Water Emulsions, Goutham Puli

Masters Theses & Specialist Projects

Scientific evidence shows that dietary intake of the omega-3 polyunsaturated fatty acids is beneficial to human health. Fish oil is a rich source of omega-3 fatty acids. However, fish oil with high levels of omega-3 PUFA is very susceptible to oxidative deterioration during storage. The objective of this study was to investigate the effect of xanthan gum (XG)-locust bean gum (LBG) mixtures on the physicochemical properties of whey protein isolate (WPI) stabilized oil-in-water (O/W) emulsions containing 20% v/v menhaden oil. The O/W emulsions containing XG/LBG mixtures were compared to emulsions with either XG or LBG alone. The emulsions were prepared …

Evidence For Sigma Factor Competition In The Regulation Of Alginate Production By Pseudomonas Aeruginosa, Yeshi Yin, T. Ryan Withers, Xin Wang, Hongwei D. Yu

Biochemistry and Microbiology

Alginate overproduction, or mucoidy, plays an important role in the pathogenesis of P. aeruginosa lung infection in cystic fibrosis (CF). Mucoid strains with mucA mutations predominantly populate in chronically-infected patients. However, the mucoid strains can revert to nonmucoidy in vitro through suppressor mutations. We screened a mariner transposon library using CF149, a non-mucoid clinical isolate with a misssense mutation in algU(AlgU^A61V). The wild type AlgU is a stress-related sigma factor that activates transcription of alginate biosynthesis. Three mucoid mutants were identified with transposon insertions that caused 1) an overexpression of AlgU^A61V, 2) an overexpression of …

Design, Development, And Characterization Of Novel Antimicrobial Peptides For Pharmaceutical Applications, Yazan H. Akkam

Graduate Theses and Dissertations

Candida species are the fourth leading cause of nosocomial infection. The increased incidence of drug-resistant Candida species has emphasized the need for new antifungal drugs. Histatin 5 is a naturally occurring human salivary antifungal peptide and the first line of defense against infections of the oral cavity. This research has focused on understanding the activity of histatin 5, and subsequently designing novel peptides that may serve as models for the further development of therapeutics to treat fungal infection.

This objective has been achieved in three steps: studying the structural requirement of histatin 5 involved in antifungal activity, the identification of …

A Force Of Nature: Molecular Mechanisms Of Mechanoperception In Plants, Gabriele B. Monshausen, Elizabeth S. Haswell

Biology Faculty Research

The ability to sense and respond to a wide variety of mechanical stimuli-gravity, touch, osmotic pressure, or the resistance of the cell wall-is a critical feature of every plant cell, whether or not it is specialized for mechanotransduction. Mechanoperceptive events are an essential part of plant life, required for normal growth and development at the cell, tissue, and whole-plant level and for the proper response to an array of biotic and abiotic stresses. One current challenge for plant mechanobiologists is to link these physiological responses to specific mechanoreceptors and signal transduction pathways. Here, we describe recent progress in the identification …

The Effects Of Growth Hormone And Thyroxine Treatment On The Insulin Signaling Of Female Ames Dwarf Mouse Skeletal Muscle Tissue, Andrew Do

HIM 1990-2015

Ames dwarf (df/df) mice are deficient in anterior pituitary hormones: growth hormone (GH), thyroid stimulating hormone (TSH), and prolactin (PRL) due to a spontaneous, homozygous mutation of prop1[superscript df] gene. These dwarf mice exhibit characteristics such as delayed growth and development coupled with delayed aging, increased lifespan, overall increased insulin sensitivity, as well as resistance to certain diseases and cancers. The mutant mice possess low blood glucose, low serum insulin, and lower body temperature. Their enhanced longevity (about 40-60% longer lifespan than normal mice) is associated with their GH deficiency and disruption in the somatotropic axis (GH/IGF-1 hormonal pathway) as …

Efficacy Of Gold Silica Nanoshells And Gold Nanorods For Photothermal Therapy Of Human Glioma Spheroids, Suyog Jung Chhetri

UNLV Theses, Dissertations, Professional Papers, and Capstones

Gold-based nanoparticles including gold-silica nano-spheres and gold nano-rods have been investigated for a number of therapeutic and diagnostic applications. The ability of these nanoparticles to convert light into heat energy makes them particularly appealing for photothermal therapy in which cancer cells are destroyed via light-induced heat generation. The overall objective of the study is to compare the efficacy of gold-silica nano-spheres and gold nano-rods in an in vitro system consisting of human brain tumor (glioma) spheroids.

Delivery of the nanoparticles to the spheroids was accomplished using murine macrophages. Nanoparticles (spheres or rods) were incubated with macrophages for 24 hours. Thereafter, …

Structure-Function Relationship Of The Ligand-Binding Domain Of The Fibroblast Growth Factor Receptor, Ryan Thurman

Graduate Theses and Dissertations

The interactions between FGF and fibroblast growth factor receptors are responsible for the regulation of key cellular processes. FGF is important in both germ cell and embryonic developments. FGF continues to play important roles during adulthood by regulating embryogenesis, cell differentiation, and wound healing (1-7). The regulations of these cellular events are initiated through FGF binding to the fibroblast growth factor receptors. The complex formed by FGF and the receptor involves a key interaction with heparin. Through interactions with heparin, the FGF, FGFR and Heparin form a 2:2:2 complex (8). This complex formation results in autophosphorylation in the tyrosine kinase …

Post-Injury Calcium Chelation Rescues Skeletal Muscle Regeneration In Mice, Matthew D. Magda

Honors Scholar Theses

During aging the ability of skeletal muscle to regenerate after injury wanes until muscle integrity cannot be maintained. In this study it is shown that calcium chelation can restore young-like regenerative ability in an aged mouse model of skeletal muscle regeneration.

Conformational Dynamics Of K-Ras And H-Ras Proteins: Is There Functional Specificity At The Catalytic Domain?, Nandini Rambahal

Dissertations and Theses (Open Access)

Ras proteins serve as crucial signaling modulators in cell proliferation through their ability to hydrolyze GTP and exist in a GTP “on” state and GTP “off” state. There are three different human Ras isoforms: H-ras, N-ras and K-ras (4A and 4B). Although their sequence identity is very high at the catalytic domain, these isoforms differ in their ability to activate different effectors and hence different signaling pathways. Much of the previous work on this topic has attributed this difference to the hyper variable region of Ras proteins, which contains most of the sequence variance among the isoforms and encodes specificity …

Bioengineering The Expression Of Active Recombinant Human Cathepsin G, Enteropeptidase, Neutrophil Elastase, And C-Reactive Protein In Yeast, Eliot T. Smith

Electronic Theses and Dissertations

The yeasts Pichia pastoris and Kluyveromyces lactis were used to express several recombinant human proteins for further biochemical characterization. Two substitution variants of recombinant human enteropeptidase light chain (rhEPL) were engineered to modify the extended substrate specificity of this serine protease. Both were secreted as active enzymes in excess of 1.7 mg/L in P. pastoris fermentation broth. The substitution variant rhEPL R96Q showed significantly reduced specificities for the preferred substrate sequences DDDDK and DDDDR; however, the rhEPL Y174R variant displayed improved specificities for these substrate sequences relative to all other reported variants of this enzyme. The neutrophil serine proteases human …

Osmotic Stress, Not Aldose Reductase Activity, Directly Induces Growth Factors And Mapk Signaling Changes During Sugar Cataract Formation, Peng Zhang, Kuiyi Xing, James Randazzo, Karen Blessing, Marjorie F. Lou, Peter Kador

School of Veterinary and Biomedical Sciences: Faculty Publications

In sugar cataract formation in rats, aldose reductase (AR) actitvity is not only linked to lenticular sorbitol (diabetic) or galactitol (galactosemic) formation but also to signal transduction changes, cytotoxic signals and activation of apoptosis. Using both in vitro and in vivo techniques, the interrelationship between AR activity, polyol (sorbitol and galactitol) formation, osmotic stress, growth factor induction, and cell signaling changes have been investigated. For in vitro studies, lenses from Sprague Dawley rats were cultured for up to 48 hrs in TC-199-bicarbonate media containing either 30 mM fructose (control), or 30 mM glucose or galctose with/without the aldose reductase inhibitors …

Cytochrome B5 Reductase Encoded By Cbr1 Is Essential For A Functional Male Gametophyte In Arabidopsis, Laura L. Wayne, James G. Wallis, Rajesh Kumar, Jennifer E. Markham, John Browse

Department of Biochemistry: Faculty Publications

In all eukaryotes, NADH:cytochrome b5 reductase provides electrons, via cytochrome b5, for a range of biochemical reactions in cellular metabolism, including for fatty acid desaturation in the endoplasmic reticulum. Studies in mammals, yeast, and in vitro plant systems have shown that cytochrome b5 can, at least in some circumstances, also accept electrons from NADPH:cytochrome P450 reductase, potentially allowing for redundancy in reductase function. Here, we report characterization of three T-DNA insertional mutants of the gene encoding cytochrome b5 reductase in Arabidopsis thaliana, CBR1. The progeny of plants heterozygous for the cbr1-2 allele segregated 6% homozygous mutants, while cbr1-3 and cbr1-4 …

Physiologically-Based Pharmacokinetic Modeling For Predicting Caffeine/Theophylline-Ciprofloxacin Interactions, David M. Ng, Ali Navid

STAR Program Research Presentations

Dynamics of interactions between the drugs caffeine, theophylline, and ciprofloxacin are predicted using physiologically-based pharmacokinetic (PBPK) modeling. Pharmacokinetic means the model determines where the drugs are distributed in the body over time. Physiologically-based means the anatomy and physiology of the human body are reflected in the structure and functioning of the model. Multiple drugs can interact to increase or decrease their beneficial and/or undesired effects. This is important because some common substances, such as caffeine in coffee, soft drinks, and energy drinks, are actually drugs that affect the body. Ciprofloxacin is an inhibitor of caffeine and theophylline metabolism; such inhibition …

Studying Aggregate Formation By Amyotrophic Lateral Sclerosis-Associated Mutant Sod1 Protein In Drosophila Model, Michael Mccarthy

Dissertations and Theses (Open Access)

A common pathological hallmark of most neurodegenerative disorders is the presence of protein aggregates in the brain. Understanding the regulation of aggregate formation is thus important for elucidating disease pathogenic mechanisms and finding effective preventive avenues and cures. Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, is a selective neurodegenerative disorder predominantly affecting motor neurons. The majority of ALS cases are sporadic, however, mutations in superoxide dismutase 1 (SOD1) are responsible for about 20% of familial ALS (fALS). Mutated SOD1 proteins are prone to misfold and form protein aggregates, thus representing a good candidate for studying aggregate formation. …

Characterization Of Jak, Stat, And Src Interactions In Head And Neck Squamous Cell Carcinoma, Reshma Jaseja, Reshma Jaseja

Dissertations and Theses (Open Access)

Recurrence of Head and Neck Squamous Cell Carcinoma (HNSCC) is common; thus, it is essential to improve the effectiveness and reduce toxicity of current treatments. Proteins in the Src/Jak/STAT pathway represent potential therapeutic targets, as this pathway is hyperactive in HNSCC and it has roles in cell migration, metastasis, proliferation, survival, and angiogenesis. During short-term Src inhibition, Janus kinase (Jak) 2, and signal transducer and activator of transcription (STAT) 3 and STAT5 are dephosphorylated and inactivated. Following sustained Src inhibition, STAT5 remains inactive, but Jak2 and STAT3 are reactivated following their early inhibition. To further characterize the mechanism of this …

A Novel Cardiac Function Of Sumo2/3 And Senp5 Dependent Pathway And Its Physiological Impact On Congestive Cardiomyopathy, Eun Young Kim

Dissertations and Theses (Open Access)

A Novel cardiac function of SUMO2/3 and SENP5 dependent pathway and its physiologic impact on congestive cardiomyopathy

Publication No.___________

Eun Young Kim, M.S.

Supervisory professor: Robert J. Schwartz, Ph.D.

SUMOylation regulates diverse cellular processes including transcription, cell cycle, protein stability, and apoptosis. Although SUMO1 has been extensively studied so far, relevance of SUMO2/3 is unclear, especially in heart. Here we show that failing heart induces SUMO2/3 conjugation. Increased SUMO2/3-dependent modification leads to congestive heart disease such as cardiac hypertrophy by promoting cardiac cell death. Calpain2 and Calpastatin as a novel SUMO2 targets have been known to be involved in mitochondrial-independent …

Biochemical Investigation Into Initiation Of Fatty Acid Synthesis In The African Trypanosomes, Sunayan Ray

All Dissertations

My doctoral studies focused on studying FA metabolism in the deadly protozoan parasite T. brucei. In my dissertation, I will be addressing various aspects of the regulation of TbACC, which catalyzes the first committed step in FA synthesis. In the second chapter, I hypothesized that TbACC is regulated in response to environmental lipids. I examined changes in TbACC RNA, protein, and activity in response to different levels of environmental lipids in both BF and PF cells. I also delineated the mechanisms by which TbACC expression and activity is regulated by phosphorylation in response to altered lipid environments. In the third …

Divergent Mechanisms Of Interaction Of Helicobacter Pylori And Campylobacter Jejuni With Mucus And Mucins, Julie Ann Naughton, Karina Mariño, Brendan Dolan, Colm Reid, Ronan Gough, Mary Gallagher, Michelle Kilcoyne, Jared Gerlachscience,, Lokesh Joshi, Pauline Rudd, Stephen Carrington, Billy Bourke, Marguerite Clyne

Articles

Helicobacter pylori and Campylobacter jejuni colonize the stomach and intestinal mucus, respectively. Using a combination of mucus-secreting cells, purified mucins, and a novel mucin microarray platform, we examined the interactions of these two organisms with mucus and mucins. H. pylori and C. jejuni bound to distinctly different mucins. C. jejuni displayed a striking tropism for chicken gastrointestinal mucins compared to mucins from other animals and preferentially bound mucins from specific avian intestinal sites (in order of descending preference: the large intestine, proximal small intestine, and cecum). H. pylori bound to a number of animal mucins, including porcine stomach mucin, but …

The Role Of Gnrh-Ii And Its Receptor In Testicular Function, Amy T. Desaulniers

Department of Animal Science: Dissertations, Theses, and Student Research

The second mammalian isoform of GnRH (GnRH-II) has been linked to regulation of cell proliferation, feed intake, and the interaction between energy balance and reproductive behavior. In contrast to the native form of GnRH (GnRH-I), GnRH-II is an inefficient modulator of gonadotropin secretion. Unlike many species, a functional receptor (GnRHR-II) specific to this ligand has been discovered in the pig that may be directly involved in testosterone production. Therefore, our objective was to identify the role of GnRH-II and its receptor in testicular function. First, there was 6-fold more GnRHR-II protein in the testis than anterior pituitary gland of boars. …

Novel Roles Of Replication Protein A Phosphorylation In Cellular Response To Dna Damage, Moises A. Serrano

Electronic Theses and Dissertations

Human replication protein A (RPA) is an eukaryotic single-stranded DNA binding protein directly involved in a variety of DNA metabolic pathways including replication, recombination, DNA damage checkpoints and signaling, as well as all DNA repair pathways. This project presents 2 novel roles of RPA in the cellular response to DNA damage. The first elucidates the regulation of RPA and p53 interaction by DNA-dependent protein kinase (DNA-PK), ataxia telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR) in homologous recombination (HR). HR and nonhomologous end joining (NHEJ) are 2 distinct DNA double-stranded break (DSB) repair pathways. Here, we report that DNA-PK, the …

Proteomic And Biochemical Studies Of Estrogen-Mediated Signaling And Novel Estrogen Receptor-Interacting Proteins In Breast Cancer Cells, Zhenqi Zhou

Graduate Theses and Dissertations

Estrogen plays essential roles in the growth, development, and homeostasis of a number of tissues, and can also be linked to the growth of breast cancer. The biological activities of estrogen are mediated by estrogen receptors (ERs) ERá and ERâ, and also orphan G-protein-coupled receptor 30 (GPR30). In order to identify novel proteins that are involved in ER-mediated actions of estrogen, we used mass spectrometry-based quantitative proteomic methods to systematically profile global protein expression in responses to E2 (17â-estradiol) stimulation in human breast cancer cell, and identify and characterize cellular novel proteins that are associated with ERs in breast cancer …

Role Of Phosphoinositide-Based Signaling In Virulence In Entamoeba Histolytica, Amrita Koushik

All Dissertations

Entamoeba histolytica is an intestinal protozoan parasite and is the causative agent of amoebiasis. Upon entering the human host, cellular processes such as adhesion, phagocytosis, motility and secretion play a vital role in its propagation and pathogenicity. In other systems, each of these cellular processes is preceded by activation of signal transduction pathways, which often involve membrane phosphoinositides such as phosphatidylinositol 4,5-bisphosphate (PI(4,5)P₂). Little is known about phosphoinositide signaling in E. histolytica pathogenicity. In this study, we demonstrated that PI(4,5)P₂ is localized to cholesterol-rich microdomains, lipid rafts, of the E. histolytica membrane and to the trailing edge …

Direction Of Aminoacylated Transfer Rnas Into Antibiotic Synthesis And Peptidoglycan-Mediated Antibiotic Resistance, Jennifer Shepherd, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Prokaryotic aminoacylated‐transfer RNAs often need to be efficiently segregated between translation and other cellular biosynthetic pathways. Many clinically relevant bacteria, including Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa direct some aminoacylated‐tRNA species into peptidoglycan biosynthesis and/or membrane phospholipid modification. Subsequent indirect peptidoglycan cross‐linkage or change in membrane permeability is often a prerequisite for high‐level antibiotic resistance. In Streptomycetes, aminoacylated‐tRNA species are used for antibiotic synthesis as well as antibiotic resistance. The direction of coding aminoacylated‐tRNA molecules away from translation and into antibiotic resistance and synthesis pathways are discussed in this review.

Dimerization Of The Glucan Phosphatase Laforin Requires The Participation Of Cysteine 329, Pablo Sánchez-Martín, Madushi Raththagala, Travis M. Bridges, Satrio Husodo, Matthew S. Gentry, Pascual Sanz, Carlos Romá-Mateo

Molecular and Cellular Biochemistry Faculty Publications

Laforin, encoded by a gene that is mutated in Lafora Disease (LD, OMIM 254780), is a modular protein composed of a carbohydrate-binding module and a dual-specificity phosphatase domain. Laforin is the founding member of the glucan-phosphatase family and regulates the levels of phosphate present in glycogen. Multiple reports have described the capability of laforin to form dimers, although the function of these dimers and their relationship with LD remains unclear. Recent evidence suggests that laforin dimerization depends on redox conditions, suggesting that disulfide bonds are involved in laforin dimerization. Using site-directed mutagenesis we constructed laforin mutants in which individual cysteine …

P2x4 Assembles With P2x7 And Pannexin-1 In Gingival Epithelial Cells And Modulates Reactive Oxygen Species Production And Inflammasome Activation, Shu-Chen Hung, Chul Hee Choi, Najwane Said-Sadier, Larry Johnson, Kalina Rosenova Atanasova, Hanen Sellami, Özlem Yilmaz, David M. Ojcius

All Dugoni School of Dentistry Faculty Articles

We have previously reported that Porphyromonas gingivalis infection of gingival epithelial cells (GEC) requires an exogenous danger signal such as ATP to activate an inflammasome and caspase-1, thereby inducing secretion of interleukin (IL)-1β. Stimulation with extracellular ATP also stimulates production of reactive oxygen species (ROS) in GEC. However, the mechanism by which ROS is generated in response to ATP, and the role that different purinergic receptors may play in inflammasome activation, is still unclear. In this study, we revealed that the purinergic receptor P2X₄ is assembled with the receptor P2X₇ and its associated pore, pannexin-1. ATP induces ROS …

Function And X-Ray Crystal Structure Of Escherichia Coli Yfde, Elwood Mullins, Kelly L. Sullivan, T. Joseph Kappock

Department of Biochemistry Faculty Publications

Many food plants accumulate oxalate, which humans absorb but do not metabolize, leading to the formation of urinary stones. The commensal bacterium Oxalobacter formigenes consumes oxalate by converting it to oxalyl- CoA, which is decarboxylated by oxalyl-CoA decarboxylase (OXC). OXC and the class III CoA-transferase formyl- CoA:oxalate CoA-transferase (FCOCT) are widespread among bacteria, including many that have no apparent ability to degrade or to resist external oxalate. The EvgA acid response regulator activates transcription of the Escherichia coli yfdXWUVE operon encoding YfdW (FCOCT), YfdU (OXC), and YfdE, a class III CoA-transferase that is ~ 30% identical to YfdW. YfdW and …

Lipid Ii-Independent Trans Editing Of Mischarged Trnas By The Penicillin Resistance Factor Murm, Jennifer Shepherd, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Streptococcus pneumoniae is a causative agent of nosocomial infections such as pneumonia, meningitis, and septicemia. Penicillin resistance in S. pneumoniae depends in part upon MurM, an aminoacyl-tRNA ligase that attaches l-serine or l-alanine to the stem peptide lysine of Lipid II in cell wall peptidoglycan. To investigate the exact substrates the translation machinery provides MurM, quality control by alanyl-tRNA synthetase (AlaRS) was investigated. AlaRS mischarged serine and glycine to tRNAAla, as observed in other bacteria, and also transferred alanine, serine, and glycine to tRNA^Phe. S. pneumoniae tRNA^Phe has an unusual U4:C69 mismatch in its acceptor stem that …

Studies Toward The Synthesis Of Lyconadin A And Cranomycin, Brad M. Loertscher

Theses and Dissertations

Lyconadin A is a pentacyclic Lycopodium alkaloid isolated from the club moss Lycopodium companatum with anticancer activity. Our approach sought to incorporate a 7-exo–6-exo acyl radical cyclization cascade to access the bicyclo[5.4.0]undecane framework of lyconadin A. Our studies created methodology for the synthesis of 5-alkyl and 3,5-dialkyl-6-carbomethoxy-2-pyridones and sterically demanding epoxide substrates. These epoxide substrates underwent an unanticipated Payne rearrangement.Cranomycin is a potent antibiotic with antiprotozoal activity. Structurally it is a cyclopentane ring system with substitution at each carbon in the ring. Another interesting structural aspect is the existence of three contiguous quaternary stereocenters including two tertiary alcohols and a …