Mechanisms Of Translational Repression Of The Sperm Mitochondria Associated-Cysteine Rich Protein (Smcp) Mrna In Round Spermatids, Danielle L. Cullinane

Graduate Doctoral Dissertations

The sperm-mitochondria-associated cysteine-rich protein (SMCP) is a male germ cell-specific protein that localizes to the outer membranes of sperm mitochondria and increases sperm motility. The Smcp mRNA is transcribed in early spermatids, and stored in a translationally repressed state for ~7 days before translation is activated in late spermatids. Identifying the cis-elements and trans-factors that repress the Smcp mRNA in early spermatids is important because these factors and elements coordinate the translational activity of hundreds of mRNAs.

A mutation was studied in transgenic mice in which the 16 nucleotides downstream of the first poly(A) signal in the Smcp …

Epigenetic Regulation Of Nuclear Hormone Receptor Dax-1, Michael B. Heskett

Master's Theses

DAX-1 (NR0B1) is an orphan nuclear receptor that plays a key role in the development and maintenance of steroidogenic tissue in mammals. Dax-1 is also expressed in mouse embryonic stem (ES) cells and is required to maintain pluripotency. Duplication of the X-chromosome in the region containing the NR0B1 gene results in sex reversal, and mutations in NR0B1 cause adrenal hypoplasia congenita. DAX-1 has been observed to act as a corepressor of other nuclear receptors including androgen receptor (AR), estrogen receptor (ER), and steroidogenic factor 1 (SF-1). In addition to pluripotent ES cells, DAX-1 is primarily expressed in select tissues of …

Biological And Physiological Condition Of Juvenile California Halibut (Paralichthys Californicus) Exposed To A Contamination Gradient In Mission Bay, Ca, Kevin Stolzenbach

Theses

Contaminated sediments in marine environments have been shown to be good indicators of ecological risk and a means to assess anthropogenic impacts on marine habitats and the animals that inhabit them (Long et al. 1995, Rattner 2009). Estuarine sediments are especially complex media with regard to physical, chemical, and biological characteristics that trap, store, modify and sometimes release contaminants to the biota (Long et al. 1995). Especially vulnerable are animals that are in constant contact with the sediments, such as flatfishes that partially bury themselves for camouflage (Costa et al. 2011). Impacts can be assessed in a number of ways, …

Development Of An Immunodiagnostic Assay For Canine Tear Lacritin, Alison Mae Enghauser

Senior Honors Projects, 2010-2019

Purpose: Lacritin is a naturally occurring human glycoprotein secreted from the lacrimal gland as a component of tears. Preliminary studies suggest that down-regulation of lacritin is associated with various ocular diseases, such as dry eye syndrome and blepharitis. Thus, lacritin shows potential as a new topical therapeutic for the treatment of ocular diseases. Previous studies have shown that recombinant human lacritin, when topically applied to rabbit eyes, promotes basal tearing. Antibodies produced against the terminal ends of human lacritin were used to develop a clinical immunodiagnostic assay that detect and quantify lacritin in human tear samples. In order to develop …

Hcpe, A Potential Immuno-Modulatory Protein From Helicobacter Pylori That Is Dependent On The Disulfide Bond Protein Dsbhp, Jeff Lester

Electronic Thesis and Dissertation Repository

H. pylori is a human gastric pathogen that colonizes ~ 50% of the world’s population. It can cause gastritis, gastric or duodenal ulcers and also gastric cancer. H. pylori produces Helicobacter cysteine rich protein HcpE, a secreted protein which may play a role in virulence. In this study we show that HcpE is secreted in the culture supernatant both as a soluble protein and in association with outer membrane vesicles, and may play a role in the modulation of H. pylori inflammatory responses. We identified that Dsb_HP is necessary for HcpE production and secretion in H. pylori, and …

Novel Mechanisms In The Sorting Of Proglucagon To The Secretory Granules Of The Regulated Secretory Pathway, Leonard M. Guizzetti

Electronic Thesis and Dissertation Repository

The prohormone proglucagon encodes for multiple peptide hormones, including glucagon, glucagon-like peptide-1 (GLP-1), and GLP-2, produced through tissue-specific processing by prohormone convertase (PC) 1/3 and PC2. In alpha cells, PC2 yields glucagon, the major counter-regulatory hormone to insulin, which together, control glucose homeostasis. In contrast, GLP-1 and GLP2 are mainly produced in intestinal L-cells by PC1/3. GLP-1 stimulates insulin secretion following a meal, and therefore has opposing function to glucagon regulating glucose homeostasis; in contrast, GLP-2 enhances gut nutrient absorption. Efficient sorting of proglucagon to secretory granules is required for nutrient-regulated secretion. The aim of this thesis is to discover …

Melatonin And Neurogenesis: A Comparative Study Of The Efficacy Of Melatonin, Its Precursors, And L-Dopa On Neural Stem Cell Metabolism In Human Adult Neurospheres, Omar Heriba

HIM 1990-2015

Human neurosphere stem cells offer promising potential for the treatment of neurodegenerative diseases. Their well characterized multi-potency of differentiating into neurons, astrocytes, and oligodendrocytes when exposed to the optimum exogenous growth factors make them an exciting area of study (38). Finding novel endogenous methods of modulating stem cell metabolism will allow for the safer treatment of various brain disorders (34). In this experiment, melatonin, N-acetylserotonin, L-tryptophan, and L-DOPA are added in three different concentrations to neurospheres suspended in HNSC/GBM media with less than optimal concentrations of exogenous epidermal growth factor (EGF) and fibroblast growth factor (FGF). The alamarBlue assay (resazurin) …

Using The Yeast Two-Hybrid System To Determine The Function Of Parkin E3 Ubiquitin Ligase, Vanessa Nguyen

HIM 1990-2015

Parkin is a cytosolic E3 ubiquitin ligase that is recruited to the mitochondria during cellular stress and has been suggested to be involved in a variety of biological processes such as mitophagy. The recruitment of Parkin (PARK2) to the mitochondria is dependent upon the kinase activity and the accumulation of PINK1 on damaged mitochondria. Mutations in either PINK1 or Parkin genes disrupt this protective pathway and lead to the accumulation of damaged mitochondria. From a clinical standpoint, mutations in the PARK2 gene have been associated with the progression and onset of autosomal recessive juvenile parkinsonism. Without the presence of a …

The Dissolution Of Cellulose In Ionic Liquids - A Molecular Dynamics Study, Barmak Mostofian

Doctoral Dissertations

The use of ionic liquids for the dissolution of cellulose promises an alternative method for the thermochemical pretreatment of biomass that may be more efficient and environmentally acceptable than conventional techniques in aqueous solution. Understanding how ionic liquids act on cellulose is essential for improving pretreatment conditions and thus detailed knowledge of the interactions between solute and solvent molecules is necessary. Here, results from the first all-atom molecular dynamics simulation of an entire cellulose microfibril in 1-butyl-3-methylimidazolium chloride (BmimCl) are presented and the interactions and orientations of solvent ions with respect to glucose units on the hydrophobic and hydrophilic surfaces …

Pore Selectivity And Gating Of Arabidopsis Nodulin 26 Intrinsic Proteins And Roles In Boric Acid Transport In Reproductive Growth, Tian Li

Doctoral Dissertations

Plant nodulin-26 intrinsic proteins (NIPs) are members of the aquaporin superfamily that serve as multifunctional channels of uncharged metabolites and water. They share the same canonical hourglass fold as the aquaporin family. The aromatic arginine (ar/R) selectivity filter controls transport selectivity based on size, hydrophobicity, and hydrogen bonding with substrates. In Arabidopsis thaliana, NIP II subclass proteins contain a conserved ar/R “pore signature” that is composed of Alanine at the helix 2 position (H2), Valine/Isoleucine at the helix 5 position (H5), and an Alanine (LE1) and an invariant Arginine (LE2) at the two loop E positions. In this study, …

Computer Simulations Of Enzymes, Jianzhuang Yao

Doctoral Dissertations

Enzymes are important catalysts in living systems, and understanding catalytic mechanisms of enzymes is an important task for modern biophysics and biochemistry. Computer simulations have emerged as very useful tools for understanding how enzymes work. In this dissertation, QM/MM MD simulations were applied to study the catalytic mechanisms of several enzymes, including sedolisin, S-adenosyl-L-methionine (AdoMet)-dependent methyltransferases, and salicylic acid binding protein 2. For sedolisin, we focus on the acylation and deacylation reactions catalyzed by the enzymes. We proposed a general acid/base mechanism involving the Glu/Asp residues at the active site. MD and QM/MM free energy simulations on pro-kumamolisin show that …

The Role Of Nag-1 In Tumorigenesis, Kyung-Won Min

Doctoral Dissertations

This dissertation explores the nature of a divergent member of the Transforming Growth Factor-β [beta] superfamily, the non-steroidal anti-inflammatory drugs activated gene (NAG-1), as it relates to its regulation and biological activity in cancer context. Our lab has extensively studied on the molecular mechanism by which phytochemicals and NSAIDs induce apoptosis correlation with NAG-1 expression in human colorectal cancer (CRC) cells. Significant data from in vitro studies suggest that NAG-1 has an anti-tumorigenic activity which elicits apoptosis in a cyclooxygenase (COX)-independent manner in CRC cells. Indeed, NAG-1 transgenic mice developed less aberrant polyp foci (APC) compared to those of control …

Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood

Doctoral Dissertations

Microbial chemotaxis receptors (chemoreceptors) are complex proteins that sense the external environment and signal for flagella-mediated motility, serving as the GPS of the cell. In order to sense a myriad of physicochemical signals and adapt to diverse environmental niches, sensory regions of chemoreceptors are frenetically duplicated, mutated, or lost. Conversely, the chemoreceptor signaling region is a highly conserved protein domain. Extreme conservation of this domain is necessary because it determines very specific helical secondary, tertiary, and quaternary structures of the protein while simultaneously choreographing a network of interactions with the adaptor protein CheW and the histidine kinase CheA. This dichotomous …

A Comprehensive Study Of The Effects Of Neurotoxins On Noradrenergic Phenotypes, Neuronal Responses And Potential Intervention By Antidepressants In Noradrenergic Cells, Yan Wang

Electronic Theses and Dissertations

It has been reported that locus coeruleus (LC) degeneration precedes the degeneration of other neurons in the brain in some neurodegenerative diseases like Alzheimer’s disease (AD) and Parkinson’s disease (PD). However, the precise mechanisms of neurodegeneration remain to be elucidated. N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) has been widely used as a noradrenergic neurotoxin in the development of AD and PD animal models for specific LC degeneration. However, the precise mechanism of action of DSP4 remains unclear. An increased systemic DNA damage caused by neurotoxin or oxidative stress has been found to be related to the pathogenic development of neurodegeneration. The process of neurodegeneration …

Jab1 Negatively Regulates Pten And Promotes Resistance To Trastuzumab In Her2-Positive Breast Cancer, Thuy T. Vu

Dissertations & Theses (Open Access)

HER2-positive breast cancer, which is characterized by the over-expression of the HER2 onco-protein, accounts for approximately 20% of all breast cancer cases. Trastuzumab (Herceptin), the first targeted therapy approved for HER2-positive disease, potently prevents the activation of signaling pathways downstream of HER2 and significantly improves patients’ outcomes. However, resistance to trastuzumab is inevitable; such resistance can occur through reduced expression of PTEN protein.

Jab1 is over-expressed in 50% of primary cancers and 90% of metastatic tumors. Our lab previously showed that depletion of Jab1 in combination with trastuzumab treatment up-regulated PTEN in mouse xenografts refractory to trastuzumab. PTEN was not …

Novel Protein Secretion And Chitin Utilization Machinery Of Flavobacterium Johnsoniae, Sampada Suresh Kharade

Theses and Dissertations

Flavobacterium johnsoniae, a member of phylum Bacteroidetes, is a gliding bacterium that digests insoluble chitin. A novel protein secretion system, the Type IX secretion system (T9SS), secretes the motility adhesins SprB and RemA and is also required for chitin utilization. In order to understand F. johnsoniae chitin utilization and the role of the T9SS, Fjoh_4555 (chiA) was targeted for analysis. Disruption of chiA resulted in cells that failed to digest chitin and complementation restored this ability. Antisera raised against ChiA were used to characterize its secretion. ChiA was secreted in soluble form by wild-type cells but remained cell-associated in T9SS …

The Role Of Stem Cells In Adipose Tissue Remodeling., Candice Reshay Holden 1988-

Electronic Theses and Dissertations

The work presented in this dissertation outlines the role of stem cells in the remodeling of adipose tissue under conditions of nutrient excess. Obesity-induced variations in adipose tissue stem cell distribution were uncovered by analysis of the stromal vascular fraction isolated from mice fed a high fat diet for several weeks. Bone marrow cell transplantation was used to determine the derivation of progenitor cells found in adipose tissue; and supplementation of depleted progenitor cell populations achieved via direct cell transplantation, helped to determine the contribution of these progenitor cells to the remodeling process. The dissertation is presented in five chapters …

Photoelectric Characterization Of Bacteriorhodopsin Reconstituted In Lipid Bilayer Membrane, Joel Kamwa

Graduate Theses and Dissertations

The objective of this work was to conduct basic research in biologically inspired energy conversion solutions. A photosynthetic protein (Bacteriorhodopsin) was reconstituted in a bi-layer membrane. Then, when a laser beam was shined on the membrane, the photon energy was used by the protein to pump protons across the membrane. The translocation of protons across the membrane was measured as photocurrent. For this purpose, a system was built to characterize the lipid bilayer membranes and to measure the photocurrent. The lipid bilayer membrane was characterized by its capacitance and resistance. A picoampere photocurrent was observed when Bacteriorhodopsin protein was present …

Oligomerization Of The Sterile-2 G-Protein Coupled Receptor In Yeast Cells In The Presence And Absence Of Alpha-Factor Pheromone Using Fluorescence Spectroscopy And Forster Resonance Energy Transfer Analysis, Joel David Paprocki

Theses and Dissertations

G-protein-coupled receptors (GPCRs) are the largest family of receptors that respond to a wide variety of extracellular stimuli, including molecular ligands such as odorants, neurotransmitters, and hormones, as well as physical agents sigh as light and pressure. The stimulation event results in initiating conformational changes in the structure of the receptor, which further results in the release of the heterotrimeric G-protein; the latter has a variety of functions within signaling pathways in cellular biology. The GPCR explored in this investigation is the Sterile 2 α-factor receptor (Ste2), whose natural function is that of a yeast mating pheromone receptor. Its natural …

Aminoglycoside-Induced Otoneurotoxicity: Analysis Of Inner Hair Cell Synaptic Plasticity Following Drug Exposure, Matthew M. Abernathy

Dissertations

Aminoglycoside antibiotics are powerful drugs for combating bacterial infections, but are limited in use due to their ototoxicity. This class of drug targets the auditory hair cells of the cochlea, causing cell death, which leads to a decline in auditory function. In spite of much research aimed at revealing a mechanism of damage, there are no co-therapies available to diminish the ototoxic liability of aminoglycosides. Existing research does show that there may be a neurodegenerative process that contributes to the observed toxicity. In an effort towards clarifying present understanding of issue, this dissertation project was conducted to characterize the neurodegenerative …

Ultrafast Interfacial Electron Transfer Across Molecule-Tio2 Nanocomposites: Towards Solar Cells And Two Photon Absorption, Edwin Mghanga

Dissertations

Interfacial charge transfer (ICT) across the molecule-TiO2 nanoparticle interface has gained enormous research attention for applications in dye sensitized solar cells (DSSC), photo-catalysis, water splitting and nonlinear optics. DSSCs are promising clean alternative energy sources. However, current DSSCs suffer from lower efficiencies and higher cost. Better understanding of the ICT processes in DSSCs can help solve these problems. We have used two strategies to understand ICT in the context of DSSCs. Firstly, we used a computationally validated anchor group, acetylacetonate (acac) to bind molecules to the semiconductor surface and facilitate charge separation. Secondly, we used natural dye sensitizers, …

Functional Characterization Of The Arginine Vasotocin 4 Receptor (Vt4r) In Sensory Circumventricular Organs Of The Chicken Gallus Gallus, Nguiessan Alphonse Aman

Graduate Theses and Dissertations

Past studies have shown that the avian vasotocin 4 receptor (VT4R), homologous to the mammalian arginine vasopressin receptor 1a (V1aR/AVPR1A) is involved in immobilization stress. It was not known, however, whether the receptor is also associated with osmotic stress, and if so, what brain regions may be involved. Four treatment groups of chicks were used for the study. One group was subjected to 1h immobilization stress and two groups were administered intraperitoneal injection of 3 M NaCl or 0.15 M NaCl. One additional group served as controls. After 1 h, blood samples were taken for the determination of plasma levels …

The Mechanism Of Lhcp Insertion Into Thylakoid Membranes, Larae Brown

Graduate Theses and Dissertations

The light harvesting chlorophyll a/b-binding proteins (LHCPs) are the most abundant membrane proteins. LHCP is a nuclear encoded protein which is targeted to the thylakoid membranes by chloroplast signal recognition particles (cpSRP). Insertion into thylakoid membranes is facilitated by the cpSRP receptor cpFtsY and the Alb3 translocase. Work here focused on understanding the molecular events of LHCP insertion into the thylakoid membranes. Specifically, we sought to develop a tool to detect the insertion of the lumen-localized loop of LHCP into thylakoid membranes, which relies on cleavage of the loop by a thylakoid lumen processing protease. We also sought to understand …

Investigation Of Nuclear And Cytoplasmic Functions Of The Dlipin Protein Of Drosophila Melanogaster, Qiuyu Chen

Graduate Theses and Dissertations

Lipin family proteins are highly conserved proteins present in species ranging from mammals to yeast. Lipin 1, the first Lipin gene identified in fatty liver dystrophy (fld) mutant mice, encodes the bifunctional protein Lipin 1, which can serve as an Mg2+-dependent phosphatidic acid phosphatase (PAP) and transcriptional co-regulator. dLipin, the single Lipin ortholog of Drosophila melanogaster, is required in triglyceride synthesis and fat body development. To study the transcriptional co-regulator activity of dLipin, nuclear receptors were screened to find receptors that interact with dLipin. The genetic interaction data indicated that Drosophila hepatic nuclear receptor 4 (HNF4) was a promising candidate …

Interaction Of Rhizobium Sp. Strain Irbg74 With A Legume (Sesbania Cannabina) And A Cereal (Oryza Sativa), Shubhajit Mitra

Theses and Dissertations

Rhizobium sp. IRBG74 (IRBG74) develops a classical nitrogen-fixing symbiosis with the legume Sesbania cannabina and also promotes the growth of rice (Oryza sativa), but not much is known about the rhizobial determinants important for these interactions. We hypothesize that Rhizobium sp. IRBG74 utilizes similar mechanisms to endophytically colonize both legume and cereal hosts. In this study, we analyzed the colonization of rice and S. cannabina using a strain of IRBG74 marked with β-glucuronidase (GUS) and Green Fluorescent Protein (GFP). IRBG74 infected both of the host plants through crack entry under submerged conditions, but showed root hair mediated infection under aerobic …

Gene Regulatory Pathways Driving Central Nervous System Regeneration In Zebrafish, Ishwariya Venkatesh

Theses and Dissertations

Damage to the central nervous system (CNS) circuitry of adult mammals results in permanent disability. In contrast, the ability to regenerate damaged CNS nerves and achieve functional recovery occurs naturally in fish. The ability of fish to successfully regrow damaged CNS nerves is in part a consequence of their ability to re-express key neuronal growth-associated genes/proteins in response to CNS injury. On such protein is Growth-Associated Protein-43 (Gap43), a protein which is highly enriched in axonal growth cones during CNS development and regeneration. Experiments conducted in mammals have demonstrated that ectopic expression of GAP-43 improves axonal re-growth after injury. Using …

Localization Of Chemoreceptors In Azospirillum Brasilense., Anastasia Aksenova

Masters Theses

In order to ensure their survival, bacteria must sense and adapt to a variety of environmental signals. Motile bacteria are able to orient their movement in a chemical gradient by chemotaxis. During chemotaxis, environmental signals are detected by chemotaxis receptors and are propagated via a signal transduction cascade to affect bacterial motility. In a model organism Escherichia coli, chemotaxis receptors, also called MCPs (for methyl-accepting chemotaxis proteins) sense changes in concentration gradients by making temporal comparisons about the chemical composition of their surroundings. Decreased attractant concentration or increased repellant concentration results in conformational changes in the MCPs that culminate …

Swarna Ramaswamy_Thesis, Swarna S. Ramaswamy

Dissertations & Theses (Open Access)

STRUCTURAL INVESTIGATIONS OF LIGAND GATED ION CHANNELS

Swarna Ramaswamy, B.S

Advisor: Vasanthi Jayaraman, Ph.D.

Ion channels form an integral part of membrane proteins. In the nervous system including the central and the peripheral nervous system, ligand gated ion channels form a very important part of intercellular communications. They receive chemical signals and convert them to electrical signal, mainly by allowing ion passage across the cell membrane. Ion passage also translates into downstream signaling events. Faithful translation of these signals and transmittance is crucial for several physiological functions, implying that irregular ion channel function could lead to serious consequences.

This thesis …

Novel Posttranslational Modification In Lkb1 Activation And Function, Szu-Wei Lee

Dissertations & Theses (Open Access)

Cancer cells display dramatic alterations in cellular metabolism to meet their needs of increased growth and proliferation. In the last decade, cancer research has brought these pathways into focus, and one emerging issue that has come to attention is that many oncogenes and tumor-suppressors are intimately linked to metabolic regulation (Jones and Thompson, 2009). One of the key tumor-suppressors involved in metabolism is Liver Kinase B1 (LKB1). LKB1 is the major upstream kinase of the evolutionarily conserved metabolic sensor—AMP-activated protein kinase (AMPK). Activation of the LKB1/AMPK pathway provides a survival advantage for cells under energy stress. LKB1 forms a heterotrimeric …

Effects Of Water Column P-Availability And Litter Microbial Mediated Processes And Stoichiometry In Aquatic Systems, Ayla Smartt

Graduate Theses and Dissertations

Anthropogenic nutrient enrichment of aquatic ecosystems is prevalent and can have detrimental effects on biological condition. Many of these effects have been attributed directly or indirectly to changes in autotrophic processes. However, in detrital-based streams changes in course detrital stoichiometry and decomposition have been related to changes community structure and production at higher trophic levels highlighting the importance of considering the heterotrophic microbial responses to enrichment. Leaf litter stoichiometry, which is determined in part by the tree species source and the microbial communities that comprise the associated biofilm, is likely related to decomposition rates, but few studies examine these variables …