Synthesis And Biophysical Analysis Of Modified Cell-Penetrating Peptides, Joel Mitchell

Theses and Dissertations (Comprehensive)

Cell-penetrating peptides (CPPs) are a family of peptides that have the ability to penetrate biological membranes. They were discovered in the late 1980s and have been the topic of many studies. Much of the interest in CPPs has been due to their ability to translocate biological membranes, and the possibility that they could offer a novel drug delivery method by conjugation to biologically active molecules. Linear CPPs can be modified to form cyclic structures. This change in structure has been observed to enhance the stability and penetrative ability of the CPPs which have been studied. The current thesis focuses on …

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 …

Exploring The Membrane Protein And Peptide Interactions Of Mitochondrial And Bacterial Lipid Systems, George Saudan

Theses and Dissertations (Comprehensive)

This study aims to expand the understanding of interactions between membrane lipids and proteins, and relate it to their biological functions in two experimental systems. The first system focuses on the interaction and conformation of a membrane protein Uncoupling Protein 4 (UCP4) in mitochondrial inner membrane lipids, in the absence and presence of cardiolipin; a lipid specific to mitochondrial inner membranes. The second system considers the interaction and conformation of a cell penetrating peptide, Penetratin, which can interact with both mammalian and bacterial cells. A N- and C-termini protected form of this 16-meric peptide (Pen2) was used to explore its …

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 …

Physiological Impacts Of Lampricides On Invasive Sea Lamprey (Petromyzon Marinus) And Non-Target Fishes, Razvan, Adrian Ionescu

Theses and Dissertations (Comprehensive)

Parasitic sea lamprey (Petromyzon marinus) ingest large quantities of blood from fishes using their oral disc and rasping tongue, most often killing the host. In the early 1900s, sea lamprey invaded the Laurentian Great Lakes, decimating sport, commercial and culturally significant fisheries. Since the early 1960s, chemical control using the lampricides 3- trifluoromethyl-4-nitrophenol (TFM) and niclosamide have helped to reduce sea lamprey populations by 90%. Lampricides are applied to larval lamprey nursery streams targeting many generations of lamprey at once. However, there is concern about the potential adverse effects of lampricides on other fishes, particularly vulnerable lake sturgeon (Acipenser fulvescens) …

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 Proteins From A Putative Chondroitin Sulfate A Degrading Operon And The Crystal Structure Of An Exo-N-Acetylgalactosamine-4-Sulfatase From Tannerella Forsythia, Peter Nguyen

Theses and Dissertations (Comprehensive)

Advanced periodontitis has been shown to have strong associations with the residence of a bacterial triad of Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola also known as the red complex. These bacteria were previously thought to be asaccharolytic, making them better suited to survive in deep in periodontal pockets where access to carbohydrates from food is limited. Information gathered from genomic analysis suggested that upregulation of an operon (BFO2285-BFO2295, BFO3043) could confer the capacity for T. forsythia to degrade chondroitin-4-sulfate, the principle glycosaminoglycan of alveolar bone tissue. Bioinformatics analysis suggested the operon was similar to an operon found in Bacteroidetes …

Structural And Functional Characterization Of Cazyme And Cazyme-Related Proteins From: Bacteroides Thetaiotaomicron And Porphyromonas Gingivalis: Two Abundant Colonizers Of The Human Microbiome, James Stevenson

Theses and Dissertations (Comprehensive)

The human body consists of approximately 30 trillion cells, while non-human microbes that reside on and within the body outnumber human somatic cells by a factor of 1.3 – 2.3. The interplay between our cells and those of the colonizing microorganisms affect physiology in a multitude of ways, both beneficial and detrimental. Microbes found in the oral cavity, such as the Red Complex member Porphyromonas gingivalis, are associated with pathology, namely periodontal diseases including gum deterioration, tooth decay, and loss of underlying alveolar bone. At the other end of the gastrointestinal tract, microbes such as Bacteroides thetaiotaomicron are found …

Synthesis And Biophysical Analysis Of The Cell-Penetrating Peptide Penetratin And Its Aromatic Analogues, An Le

Theses and Dissertations (Comprehensive)

Cell-penetrating peptides (CPPs) interact with biological membranes, undergo cellular intake/uptake, and may act as potential drug delivery agents. Understanding the molecular interactions of these peptides with membranes contributes to gaining a better knowledge of their potential use in medical and pharmaceutical applications to improve human health. The current research focuses on understanding the mechanisms of a CPP in interaction with different model phospholipid membranes. The peptide penetratin (primary sequence: RQIKIWFQNRRMKWKK) is an example of a CPP that can interact with and pass through biological membranes. The current thesis provides spectroscopic and calorimetric evidence that penetratin associates with lipid membranes. Circular …

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 …

Characterization Of The Microbial Phosphonate-Activating Pntc Enzymes, Kyle Rice

Theses and Dissertations (Comprehensive)

New strategies are urgently needed to combat infectious diseases in an era of rising antibiotic resistance. Furthermore, an emerging appreciation for the human microbiome’s role in maintaining health motivates discovery of species-specific antibiotics that minimally disrupt our native bacterial communities. Small molecule modifications to bacterial cell surfaces represent a potentially rich source of new targets for next generation antibiotics, as these molecules mediate virulence and evasion of the host immune response. Phosphocholine (PCho) is a rare cell surface modification that contributes to virulence, and modifications with phosphonates like 2-aminoethylphosphonate (AEP) are even more unusual and therefore provide opportunities for species- …

Characterization Of The Red Complex Bacterial Biofilm, Alena Pratasouskaya

Theses and Dissertations (Comprehensive)

Commonly associated with severe inflammation and destruction of the tooth-supporting tissue is bacterial consortia Treponema denticola, Tannerella forsythia, and Porphyromonas gingivalis, collectively referred to as the red complex. The red complex uses the common bacterial strategy of producing and embedding itself in extracellular polymeric substance, which contributes to the recalcitrance of periodontitis and was therefore of interest in this study. The red complex static cultures were grown in combination with different chemicals in order to establish what changes accompany these chemical challenges. This research established that extracellular polymeric substance carbohydrate yields increased with time. Interestingly, carbohydrate composition …

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 …

Bioinformatic Interrogation Of Phosphonate Tailoring Pathways, Monica Papinski

Theses and Dissertations (Comprehensive)

Phosphonates represent an underexploited class of natural products despite their tremendous potential for use in medicine and agriculture. Even less characterized are phosphonate-containing macromolecules such as cell wall lipids and glycans, distinguished by a P-C bond known to provide stability towards hydrolysis. Despite some progress made in revealing cell wall phosphonate tailoring (Pnt) pathways, several barriers impede the discovery and characterization of novel phosphonate biosynthetic pathways. Specifically, a large diversity of gene composition and arrangement is evident surrounding key genes established to participate in phosphonate tailoring pathways, which are identified alongside the presence of the ppm gene encoding the P-C …

Initial Functional Characterization Of Bfo 2291 And Bfo 2294 From Tannerella Forsythia; Degraders Of Chondroitin Sulfate A, Rony Eshaque, Rony Eshaque

Theses and Dissertations (Comprehensive)

Periodontitis is characterized by the inflammation of the periodontal tissues in response to bacterial action. The Global Burden of Disease (GBD) 2010 study shows that periodontitis ranks 6^thin the global prevalence of oral health conditions and affects 11% of the world population. It is initiated by the formation of biofilms containing different types of bacteria. These biofilms exist as dental plaque and contain three types of bacteria called Tannerella forsythia, Porphyromonasgingivalis, and Treponema denticola. These three types of bacteria are strongly associated with periodontitis and they are termed as the Red complex. The main focus of the …

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 …

The Kinetic Characterization Of Two Putative Galactosidases, Bt2857 And Sco6594, And The Preliminary Analyses Of Sco6595-97, Maria Ngo

Theses and Dissertations (Comprehensive)

Bacteroides thetaiotaomicron is a prolific bacterium found in the distal intestinal tract of humans that possesses the ability to breakdown complex polysaccharides through the release of carbohydrate-active enzymes (CAZymes). Overall, the saccharolytic prowess of B. thetaiotaomicron presents an intriguing model for understanding microbial-host nutrient exchange within the gut and to identify novel mechanisms for accessing carbohydrates. The successful expression, purification, and preliminary kinetic characterization of BT2857 are reported. BT2857 was found to be enzymatically active against the artificial substrate, 4-nitrophenyl β-D-galactopyranoside (pNP-Gal); suggesting its role as a putative β-galactosidase and allowed for the quantification of BT2857 activity by the determination …

A Biophysical Study Of The Ion Transport Mechanism In Uncoupling Protein 2 By Investigating The Role Of Lysine Residues In Its Matrix Network, Stephanie O. Uwumarenogie

Theses and Dissertations (Comprehensive)

ABSTRACT

Uncoupling protein 2 (UCP2) is one of five UCP homologues found in the inner mitochondrial membrane that transports protons from the intermembrane space to the mitochondrial matrix. In turn, the proton motive force is dissipated and less ATP is produced in the mitochondria. UCP2 is proposed to influence insulin secretion in type II diabetes, and decrease the amount of reactive oxygen species produced in the mitochondria, however the detailed mechanism of ion (proton and anions) transport in UCP2 and other UCP homologues are not fully understood. Sequence alignment analysis performed on proteins in the mitochondrial carrier family (MCF) including …

The Role Of Oxidative Stress In The Mechanisms Of Ammonia-Induced Brain Swelling And Tolerance In The Goldfish (Carassius Auratus), David F. Jones Lisser Mr.

Theses and Dissertations (Comprehensive)

Toxic build-ups of ammonia can cause potentially fatal brain swelling in mammals, but such swelling is reversible in the anoxia- and ammonia-tolerant goldfish (Carassius auratus). The mechanisms of ammonia-induced brain swelling and tolerance remain elusive, but several studies have suggested a role for reactive oxygen species (ROS), which may damage proteins and lipids in the plasma membrane of astrocytes in the brain. As a result, osmotic gradients across cell membranes may be altered leading to water uptake by astrocytes and swelling. While a role for ROS has been proposed in mammals, no studies have addressed this question in …

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 …

Characterization Of The Transporter Protein Sodium-Potassium Adenosine Triphosphatase In The Myelin Membrane, Dara E C Schaefer

Theses and Dissertations (Comprehensive)

Sodium-potassium adenosine triphosphatase (Na⁺/K⁺-ATPase) is an integral membrane protein with known involvement in the maintenance of resting membrane potentials, nutrient uptake, cellular signal transduction, and cell-cell adhesion. The functional enzyme contains a catalytic alpha subunit and a glycosylated beta subunit, of which three isoforms of each are known to exist in the central nervous system (CNS). Altered expression and/or activity of Na⁺/K⁺-ATPase subunit isoforms has been previously implicated in the pathophysiology of several neurological disorders. This study characterized Na⁺/K⁺-ATPase expression and distribution in the myelin membrane, identified its …

Distribution And Elimination Of 3-Trifluoromethyl-4-Nitrophenol (Tfm) By Sea Lamprey (Petromyzon Marinus) And Non-Target, Rainbow Trout (Oncorhynchus Mykiss) And Lake Sturgeon (Acipenser Fulvescens), Michael W. Le Clair

Theses and Dissertations (Comprehensive)

The pesticide, 3-trifluoromethyl-4-nitrophenol (TFM), has been highly successful in the control of sea lamprey (Petromyzon marinus) populations in the Great Lakes. Treatments with TFM involve applying it to streams, where it targets larval sea lamprey which live burrowed in the stream substrate. While the toxic mechanism of TFM has been elucidated, and its effects on sea lamprey described, its effects on non-target fish species such as rainbow trout (Oncorhynchus mykiss) and lake sturgeon (Acipenser fulvescens) are not as well understood. The present work demonstrated that rainbow trout show a great capacity to detoxify the lampricide using glucuronidation, when exposed to …

Proteomic Analysis Of The Highly Detergent Resistant Radial Component Of Myelin, Vatsal M. Patel

Theses and Dissertations (Comprehensive)

The wrapping of multiple layers of myelin membrane sheets around an axon plays an important role in normal neuronal function. In the central nervous system (CNS), oligodendrocytes are responsible for forming multiple myelin internodes which consist of lipids and proteins. Within these regions, there are various membrane microdomains including the radial component/tight junctions. The radial component is a junctional complex believed to stabilize the myelin membranes in the CNS myelin. In this study, the radial component from bovine and mouse myelin was isolated using differential detergent extraction. A highly detergent resistant fraction, containing previously identified proteins of the radial component …

Lipid Raft Formation And Peptide-Lipid Interactions In Myelin Model Membranes, Ashtina R. Appadu

Theses and Dissertations (Comprehensive)

Multiple sclerosis (MS), a demyelinating disease affecting 75,000 Canadians and almost 400,000 Americans, is one of the most prevalent diseases in young adults. Unfortunately, there exist no known cures to date and the pathways involved in the progression of the disease remain relatively obscure. The demyelination process triggered by the onset of MS, affects the lipid composition of the myelin membrane and causes a loss in viable myelin which can in turn greatly impact the proper functioning of the central nervous system (CNS). The cholesterol content of myelin fluctuates during MS and consequently this could affect the fluidity as well …