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 …

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 …

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 …

Biological Surveys Of Selected Lower Grand River Streams: Ionia, Kent, Muskegon, And Ottawa Counties, Michigan, August-September 2014, Michigan Department Of Environmental Quality Water Resources Division

Faculty and Professional Research

The biologic integrity and physical habitat conditions of the lower Grand River (Hydrologic Unit Code (HUC) 04050006) and selected tributaries were surveyed during August and September 2014 by staff of the Surface Water Assessment Section (SWAS), Water Resources Division (WRD). The objectives of this study were to: 1. Evaluate the attainment status of the other indigenous aquatic life and wildlife (OIALW) designated use. 2. Identify and investigate effects of nonpoint sources (NPS) of pollution. 3. Satisfy monitoring requests submitted by internal and external customers.

Amino Acid Racemase Enzyme Assays, Atanas D. Radkov, Luke A. Moe

Plant and Soil Sciences Faculty Publications

Amino acid racemases are enzymes that invert the α-carbon stereochemistry of amino acids (AAs), interconverting amino acids between their L- and D-enantiomers in a reversible reaction. In bacteria, they are known to have catabolic physiological functions but are also involved in the synthesis of many D-AAs, including D-glutamate and D-alanine, which are necessary components of the peptidoglycan layer of the bacterial cell wall. As such, amino acid racemases represent significant targets for the development of bactericidal compounds. Amino acid racemases are also regarded by the biotechnological industry as important catalysts for the production of economically relevant D-AAs. Here, we provide …

Clpxp Modulates Cell Growth And Morphology In Cell Shape Mutants Of E.Coli, Ryann Murphy

Senior Honors Projects

ClpXP modulates cell growth and morphology in cell shape mutants of E. coli

Ryann Murphy¹ and Jodi L. Camberg¹

¹University of Rhode Island, Department of Cell and Molecular Biology, Kingston, RI, 02881

Penicillin Binding Proteins (PBPs) are a family of prokaryotic membrane proteins named for their propensity to bind the antibiotic penicillin and are involved in remodeling and deposition of peptidoglycan. In wild type Escherichia coli cells, the uniform rod shape is conserved across generations. E.coli cells containing multiple deletions of Low Molecular Weight (LMW) PBPs exhibit irregular shapes. LMW PBP5 (dacA) is a potential …

Functional Analysis Of Cytosolic Hsp70 Nucleotide Exchange Factor Networks In Yeast, Jennifer Lynn Abrams

Dissertations & Theses (Open Access)

The Hsp70 class of molecular chaperones play critical roles in protein homeostasis via an ATP-dependent folding cycle. Cytosolic Hsp70s in the budding yeast Saccharomyces cerevisiae, Ssa and Ssb, interact with up to three distinct nucleotide exchange factors (NEFs) homologous to human counterparts; Sse1/Sse2/HSP110, Fes1/HspBP1, and Snl1/Bag1. In an effort to understand the differential functional contributions of the cytosolic NEFs to protein homeostasis (“proteostasis”), I carried out comparative genetic, biochemical and cell biological analyses. For these studies, I developed protocols to monitor protein disaggregation and reactivation in a near real-time coupled assay that revealed the importance of aggregate dynamics in the …

Enzyme Activity, Maturation And Regulation Of Anaerobic Reductases In Shewanella Oneidensis Mr-1, Kenneth L. Brockman

Theses and Dissertations

Shewanella oneidensis MR-1 is a metal-reducing bacterium capable of using a wide range of terminal electron acceptors. These include oxygen, metal oxides and organic compounds such as dimethyl sulfoxide (DMSO) and fumarate. In addition, several nitrogen and sulfur based compounds can be used as terminal electron acceptors, including sulfite, for which the terminal reductase was recently identified as an octaheme c-type cytochrome that contains an atypical heme binding site. In this study, several additional components involved in sulfite reduction were identified. These include SirCD that form a membrane-bound electron-transferring complex with SirA, SirBI that appear to be involved in protein …

Characterization Of Ftsa-Ftsn Interaction During Escherichia Coli Cell Division, Kimberly.Busiek@Gmail.Com K. Busiek

Dissertations & Theses (Open Access)

Division of a bacterial cell into two equal daughter cells requires precise assembly and constriction of the division machinery, or divisome. The Escherichia coli divisome includes nearly a dozen essential cell division proteins that assemble at midcell between segregating sister chromosomes. FtsZ, a homolog of eukaryotic tubulin, is the first essential cell division protein to localize at midcell where it polymerizes into a ring-shaped scaffold (Z ring). Establishment of the Z ring is required for recruitment of downstream cell division proteins including FtsA, a cytoplasmic protein that tethers the Z ring to the inner membrane. Following localization of FtsA and …

Structure-Based Design Of Novel Inhibitors And Ultra High Resolution Analysis Of Ctx-M Beta-Lactamase, Derek Allen Nichols

USF Tampa Graduate Theses and Dissertations

The emergence of CTX-M class-A extended-spectrum β-lactamases, which confer resistance to second and third-generation cephalosporins, poses a serious health threat to the public. CTX-M β-lactamases use a catalytic serine to hydrolyze the β-lactam ring. Specifically, the hydrolysis reaction catalyzed by CTX-M β-lactamase proceeds through a pre-covalent complex, a high-energy tetrahedral acylation intermediate, a low-energy acyl-enzyme complex, a high-energy tetrahedral deacylation intermediate after attack via a catalytic water, and lastly, the hydrolyzed β-lactam ring product which is released from the enzyme complex. The crystallographic structure of CTX-M at sub-angstrom resolution has enabled us to study enzyme catalysis as well as perform …

Comparison Of Two Separation Methods For Biological Particles: Field-Flow Fractionation (Fff) And Sucrose Density Gradients, Cody E. Garrison

OES Theses and Dissertations

Sucrose gradient centrifugation and Field-flow fractionation (FFF) are two different particle separation methods that overcome the problems of similar size microorganisms clumping together during standard filtration methods. FFF separates particles based on size and density via the parabolic velocity profile of laminar flow in a ribbon-like channel. The sucrose method separates particles via centrifugation in a density gradient. Both techniques worked well in separating eukaryotic from prokaryotic microbes, with the preferred method depending on the type and relative abundance of organisms to be separated. Minicells were separated from mother cells in transformed Escherichia coli cultures, heterotrophic flagellates (e.g., Diplonema papillatum …

Virus Purification, Detection And Removal, Khrupa Saagar Vijayaragavan

Dissertations, Master's Theses and Master's Reports - Open

The biopharmaceutical industry has a growing demand and an increasing need to improve the current virus purification technologies, especially as more and more vaccines are produced from cell-culture derived virus particles. Downstream purification strategies can be expensive and account for 70% of the overall manufacturing costs. The economic pressure and purification processes can be particularly challenging when the virus to be purified is small, as in our model virus, porcine parvovirus (PPV). Our efforts are focused on designing an easy, economical, scalable and efficient system for virus purification, and we focused on aqueous two-phase systems. Industry acceptable standards for virus …

Ether Bridge Formation And Chemical Diversification In Loline Alkaloid Biosynthesis, Juan Pan

Theses and Dissertations--Plant Pathology

Loline alkaloids, found in many grass-Epichloë symbiota, are toxic or feeding deterrent to invertebrates. The loline alkaloids all share a saturated pyrrolizidine ring with a 1-amine group and an ether bridge linking C2 and C7. The steps in biosynthesis of loline alkaloids are catalyzed by enzymes encoded by a gene cluster, designated LOL, in the Epichloë genome. This dissertation addresses the enzymatic, genetic and evolutionary basis for diversification of these alkaloids, focusing on ether bridge formation and the subsequent modifications of the 1-amine to form different loline alkaloids.

Through gene complementation of a natural lolO mutant and comparison …

A Structural And Functional Comparison Of Human Immunodeficiency Virus Type 1 Nucleocapsid Protein (Ncp7) And Other Retroviral Nucleocapsid Proteins, Christopher Richard Cavender

Legacy Theses & Dissertations (2009 - 2024)

Human immunodeficiency virus type 1 (HIV-1) is a retrovirus belonging to the lentivirus genus of the orthoretrovirinae family. HIV-1 is widely known for causing acquired immunodeficiency syndrome (AIDS) in humans and being responsible for 1.8 million deaths due to AIDS associated illnesses in 201016.

The Role Of Surface Chemistry In The Toxicity Of Manufactured Cerium Dioxide Nanomaterials To Caenorhabditis Elegans, Emily Kay Oostveen

Theses and Dissertations--Plant and Soil Sciences

Manufactured CeO₂ nanomaterials (CeO₂-MNMs) are used for a wide variety of applications including diesel fuel additives and chemical/mechanical planarization media. To test the effects of CeO₂-MNM surface coating charge on to model organism Caenorhabditis elegans, we synthesized 4 nm CeO₂ with cationic (DEAE-), anionic (CM-), and neutral (DEX) coatings. In L3 nematodes exposed for 24 hours, DEAE-CeO₂ induced lethality at lower concentrations than CM- or DEX-CeO₂. Feeding slightly decreased CeO₂ toxicity, regardless of coating. In L2 nematodes exposed for 48 hours with feeding, DEAE-CeO₂ caused lethality at the …

Purification Of An Inducible Dnase From A Thermophilic Fungus, Kyle Landry, Andrea Vu, Robert Levin

Kyle S Landry

Purification And Characterization Of Iso-Ribonucleases From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin

Kyle S Landry