Characterization Of The Clostridioides Difficile Glycosyl Hydrolase Ccsz, Brian Lowrance

Theses and Dissertations (Comprehensive)

Bacteria inhabit many of the harshest environments on Earth; persisting and thriving in conditions thought to be unsuitable for life. One common strategy to withstand these environments is the formation of a biofilm. Biofilm composition varies greatly, depending on the underlying community that produces it. Cellulose, a polymer consistently prevalent in biofilms, has been identified as a virulence factor in many pathogens and is suspected to be involved in pathogenesis by Clostridioides difficile. C. difficile is the #1 cause of hospital acquired diarrhea, which can range from mild to life-threatening infections. Biofilm formation is hypothesized to be involved in …

Discovery Of Inhibitors Of Peptidoglycan O-Acetyltransferase B (Patb) From Neisseria Gonorrhoeae, A New Potential Antibacterial Target, Stefen Stangherlin

Theses and Dissertations (Comprehensive)

Experts project that by 2050, 10 million lives will be lost annually as a result of antimicrobial resistant infections, surpassing all current leading causes of death, and costing the global economy $100 trillion USD on healthcare efforts. To promote research and development of novel antibiotics, the World Health Organization and Centers for Disease Control and Prevention released a list of priority pathogens regarded as serious or urgent threats of antimicrobial resistance. Many pathogenic bacteria, including several priority pathogens, produce O-acetylated peptidoglycan to establish infection and avoid host immune responses. Consequently, the enzymes responsible for producing O-acetylated peptidoglycan in Gram-negative pathogenic …

On The Structure And Function Of Mitochondrial Uncoupling Proteins: The Case Of Ucp2, Afshan Ardalan

Theses and Dissertations (Comprehensive)

Uncoupling proteins (UCPs) are regulated proton transporters of the mitochondrial inner membrane. UCP-mediated proton leak negatively impacts the rate of ATP synthesis. Despite the importance of their physiological role(s) in certain tissues, molecular aspects of UCPs’ structure-function relationships are not fully understood. The current study explores the tertiary and quaternary structure of UCP2, as well as its proton transport mechanism in lipid membranes. The proteins were expressed in the E. coli inner membrane, purified and reconstituted into liposomes. Proteins were characterized by semi-native SDS-PAGE. Circular dichroism spectroscopy (CD) and fluorescence quenching assays were utilized to study the conformation of proteins …

A Bioinformatic Analysis Of The Biosynthesis Of Carotenoids In The Copepod Tigriopus Californicus, Anchalya Balasubramaniam

Theses and Dissertations (Comprehensive)

Abstract

Biological pigments, also called biochromes, are coloured compounds which are displayed by a variety of life forms, including animals, due to selective colour absorption. The combination of light absorption and reflection enables each pigment to portray a distinct colour which results in the broad spectrum of colours we observe in our surroundings. Carotenoids are a large group of yellow, orange, and red biological pigments found in living organisms. Our current biomolecular knowledge of carotenoids is heavily derived from studying the pathway in photosynthetic prokaryotes, bacteria, fungi, and plants. Carotenoid pigments are exceptionally multifunctional as they act as photo-protectors against …

Functional Characterization Of O-Acetyltransferase Wssi: Role In Bacterial Cellulose Acetylation Of Achromobacter Insuavis And Pseudomonas Fluorescens, Alysha Burnett

Theses and Dissertations (Comprehensive)

Cellulose biofilms consist of a community of bacterial cells encased in a self-produced matrix of polymers (e.g. exopolysaccharides, such as cellulose) that facilitate a firm adherence to surfaces. The acetylation (addition of an acetyl group on carbohydrates) is crucial in virulence; thereby in some cases allowing opportunistic bacteria to cause harmful diseases. Pertaining to this research, the wrinkly spreader (WS) genotype of Pseudomonas fluorescens colonizes the air-liquid interface on food, water sources and human tissue to form a robust biofilm with the ability to spread across surfaces. The composition of this biofilm largely consists of bacterial cellulose polymers …

Characterization Of Wssf; A Putative Acetyltransferase From Achromobacter Insuavis And Pseudomonas Fluorescens, Cody Reese

Theses and Dissertations (Comprehensive)

Biofilms are a survival mechanism commonly employed by communities of bacteria for adherence and protection. Bacteria produce a matrix of polymers (e.g. exopolysaccharides, such as cellulose) that allow them to exert control on their local environment. In the case of cellulose biofilms, acetylation (addition of acetate on carbohydrates) is paramount for polymer integrity and in some cases virulence. For this research, the wrinkly spreader (WS) genotype of the emergent human pathogen Achromobacter insuavis facilitates infections of the eyes of contact lens wearers and the lungs of Cystic Fibrosis patients (CF). Chronic infections have created a growing concern for the protective …

Expression, Purification, Functional Characterization And Crystallization Of Three Porphyromonas Gingivalis Gene Products, Katarina Mandic

Theses and Dissertations (Comprehensive)

Dental biofilms are coupled polymicrobial aggregates that have attached to solid surfaces in the oral cavity. These collections of microorganisms are known to cause periodontal diseases that commence as localized inflammation of the gingiva and if untreated, eventually lead to irreversible alveolar bone resorption and tooth loss. Porphyromonas gingivalis is one of three periodontal pathogens that make up the “Red Complex”; a bacterial consortium responsible for the production of polysaccharide-rich biofilms that are essential to the inception and progression of periodontal disease. The dysbiosis and destructive inflammation caused by these organisms propel a self-sustained feed-forward loop that perpetuates periodontal disease. …

Structural Investigation Of Bcsc: Insight Into Periplasmic Transport During Cellulose Export, William Scott, Joel T. Weadge

Theses and Dissertations (Comprehensive)

A biofilm can be defined by a community of microbes coexisting within a self-produced protective polymeric matrix. Exopolysaccharide (EPS) is a key component in biofilms and a contributor to their virulence and pathogenicity. The cellulose bacterial synthesis complex is one such EPS system that is found in many Enterobacteriaceae,including Escherichia coli and Salmonella spp., and is responsible for the production and secretion of the EPS cellulose. BcsC is the periplasmic protein responsible for the export of the exopolysaccharide cellulose and was the focus of this research. Sequence homology comparisons and structural predictions between BcsC, and the previously characterized alginate …

Structural And Functional Analysis Of Three Upregulated Gene Products, Tde0626, Tde1701, And Tde2714 From Treponema Denticola During Biofilm Formation, Jonah Nechacov

Theses and Dissertations (Comprehensive)

The progression of human chronic periodontitis within periodontal disease has been often linked to the presence of key pathogens, such as the presence of Treponema denticola, a late colonizer found in the deepening pockets of the gingival sulcus. This pathogen, as well as its associates Porphyromonas gingivalis and Tannerella forsythia, are classified as the ‘red complex’ and exist in a mixed biofilm during infection. It is within this biofilm state that previous transcriptomic analysis revealed a total of 126 genes that had an increase in their expression by 1.5-fold or greater in T. denticola. Three of these …

Characterizing The Cellulose-Modifying Enzyme Bcsg From Escherichia Coli, Alexander Anderson, Joel T. Weadge

Theses and Dissertations (Comprehensive)

Microbial biofilms are communities of microorganisms that exhibit co-operative behaviour, producing a matrix of exopolysaccharide that enmeshes the community. The well-studied human pathogens Escherichia coli and Salmonella entericaproduce a biofilm matrix comprised chiefly of the biopolymer cellulose, along with amyloid protein fibers termed curli. This biofilm matrix confers surface adherence and acts as a protective barrier to disinfectants, antimicrobials, environmental stressors, and host immune responses. Pertaining to this research, the bcsEFG operon, conserved in the Enterobacteriaceae, encodes an inner membrane-spanning complex responsible for the addition of a phosphoethanolamine (pEtN) modification to microbial cellulose, essential for extracellular matrix assembly and …

Evidence For Extra-Gastric Expression Of The Proton Pump H+/K+ -Atpase In The Gills And Kidney Of The Teleost Oreochromis Niloticus, Ebtesam Barnawi

Theses and Dissertations (Comprehensive)

It is well known that stomach acid secretion by oxynticopeptic cells of the gastric mucosa is accomplished by the H⁺/ K⁺-ATPase (HKA), which is comprised of the HKα1 (gene: atp4a) and HKβ (gene: atp4b) subunits. However, the role of the HKA in extra-gastric organs such as the gill and kidney is less clear especially in fishes. This pump may contribute to active ion and/or acid-base regulation either through direct ion transport or through secondary transport proteins against unfavorable concentration gradients via the energy derived from ATP hydrolysis. In the present work I have demonstrated …

Relationships Between Factors Influencing Biofilm Formation And Pathogen Retention In Complex Rhizosphere Microbial Communities, Aaron Coristine

Theses and Dissertations (Comprehensive)

Riparian wetlands are unique habitats facilitating all forms of life. The riverbanks of these environments provide ideal conditions for bacteria, plants, and higher organisms. Of particular interest to this research was the variation in microbial community structure at high, intermediate and poor water quality impacted areas. Assessing the capabilities of plants to retain microbial pathogens was identified. Root systems and corresponding soil are ideal locations for bacterial deposition, resulting in attachment at these areas. Biofilm production in these regions is important for long-term establishment, leading to persistence and potential naturalization. Opportunistic pathogens originating from mammalian fecal matter are introduced into …

Characterization Of A Phosphonate-Specific Cytidylyltransferase, Kissa Batul

Theses and Dissertations (Comprehensive)

Antibiotic resistance is a major global health concern that requires new therapeutic approaches. Furthermore, a lack of narrow spectrum antibiotics on the market produces unintended consequences with respect to changes in our microbial make up. Phosphonates are reduced versions of phosphates that possess a C-P bond which is more resistant to enzymatic and chemical degradation. The role of phosphonate containing macromolecules (e.g. cell surface polysaccharides) remains enigmatic, however their presence suggests that they may confer an advantage. The biosynthesis of phosphonate-containing macromolecules is unknown, but a pathway is proposed involving aLicC type cytidylyltransferase-catalyzed conjugation to a phosphonate followed by a …

Purification And Characterization Of Bcsc; An Integral Component Of Bacterial Cellulose Export, Emily D. Wilson Ms

Theses and Dissertations (Comprehensive)

Biofilms are a growing concern in the medical field due to their increased resistance to antibiotics. When found in a biofilm, bacteria can have antibiotic resistance 10-1000 times that of their planktonic counterparts. Therefore, it is important to study the formation of biofilms. Cellulose biofilms are formed by Enterobacteriaceae, such as many Escherichia coli and Salmonella spp. strains. Biofilms provide these species with benefits including antimicrobial protection, development of bacterial communities, promotion of DNA exchange, uptake of nutrients, and, in the case of cellulose biofilms, immune system evasion. Cellulose biofilms are controlled by the Bacterial cellulose synthesis (Bcs) complex located …

Biophysical Characterization Of The Folding, Membrane Topology And Ion Transport Activity Of Ucp2 Using Selective Trp Mutants, Tyler C. Auld

Theses and Dissertations (Comprehensive)

Human Uncoupling Protein 2 (hUCP2) is one of five known human UCPs which are found in the inner mitochondrial membrane and have been shown to facilitate the translocation of protons from the intermembrane space to the mitochondrial matrix. The detailed physiological role of UCP2 proton transport, the mechanism by which it mediates this proton transport, as well as its structure has also yet to be elucidated. In order to help determine the topology of UCP2 embedded in the membrane as well as its mechanism of proton transport, the intrinsic fluorescence properties of the two tryptophan residues (Trp) present in its …

Characterization Of The Trans-Plasma Membrane Electron Transport System In The Myelin Membrane, Afshan Sohail

Theses and Dissertations (Comprehensive)

Myelination is the key feature of evolution in the nervous system of vertebrates. Myelin is the protrusion of glial cells. More specifically, "oligodendrocytes" in the central nervous system (CNS), and "Schwann" cells in the peripheral nervous system (PNS) form myelin membranes. Myelin remarkably, enhances the propagation of nerve impulses. However, myelin restricts the access of extracellular metabolites to the axons. A pathology called "demyelination" is associated with myelin. The myelin sheath is not only an insulator, but it is itself metabolically active. In this study it is hypothesized that the ratio of NAD(P)⁺/NAD(P)H and the glycolytic pathway of …

A Structure-Function Analysis Of The Arabidopsis Chloroplast Import Protein Attic20, James H. Campbell

Theses and Dissertations (Comprehensive)

Arabidopsis thaliana protein Tic20 (atTic20) is a member of the translocon at the inner envelope membrane of chloroplasts. Evidence to date suggests it is part of the main preprotein conducting aperture in the complex, but its exact role is still debated. To help characterize its role, a protocol optimizing yield and purity of recombinantly expressed atTic20 was developed, and a series of experiments was performed to examine its secondary structure and its ability to interact with chloroplast transit peptides. The attempt to increase protein yield was successful, with growth at 20^oC in the auto-inducing media ZYP-5052 showing the …

Characterizing Dsrna Production In Virus-Infected Fish Cells, Amal Brek Aloufi

Theses and Dissertations (Comprehensive)

Viral dsRNA is produced by almost all viruses sometime during their replicative cycle. These viral nucleic acids are potent inducers of both innate and adaptive immune responses, and are therefore considered important immuno-modulators. Previous studies have shown that viruses produce dsRNA when replicating in mammalian cells; however, to date no one has demonstrated viral dsRNA production in virus infected fish cells. Therefore, the goal of this study is to investigate dsRNA production by fish viruses in fish cells, verifying production and performing initial characterization of the dsRNA molecules being produced. Three different rainbow trout cell lines were used in this …

An Investigation Of Alternative Oxidase Presence, Expression, And Regulation In The Moss Physcomitrella Patens, Karina I. Neimanis

Theses and Dissertations (Comprehensive)

Alternative oxidase (AOX) is an inner mitochondrial membrane protein that introduces a branch point at ubiquinone within the respiratory electron transport system (ETS). The AOX protein bypasses two sites of proton translocation within the ETS and as a result the yield of ATP per oxygen consumed is significantly reduced. Although AOX appears to be energetically wasteful, recent studies have revealed that AOX has a wide taxonomic distribution. AOX multigene families, transcripts, protein levels, and enzymatic activity have been most thoroughly characterized in many angiosperm (flowering) plants. Given the data available for angiosperm AOXs, evidence of non-angiosperm AOXs in the primary …

Toc Complex Formation: An Investigation Of The Interactions Governing Toc Complex Composition And Assembly, Steven R. Siman

Theses and Dissertations (Comprehensive)

Chloroplast-destined preproteins are translated in the cytosol, and posttranslationally targeted to and translocated across the double envelope membrane of the chloroplast by the coordinated activities of two translocon complexes: the Translocons at the Outer and Inner envelope membrane of the Chloroplast (TOC and TIC, respectively). In the model organism Arabidopsis thaliana the core TOC components include two families of GTPase receptors: TOC159 (atToc159, -132, and -120) and TOC34 (atToc33 and -34). These receptor families are hypothesized to assemble into distinct complexes and recognize transit peptides present on the N-terminus of chloroplast-destined preproteins. The GTPase domains of the TOC159 and TOC34 …