Medical Sciences Commons^™

Endosomal Trafficking As A Determinant Of Antifungal Tolerance In The Pathogenic Fungus Candida Albicans, Arturo Luis Luna

Theses and Dissertations (ETD)

Several important antifungal drugs inhibit the synthesis of ergosterol, a lipid that modulates the thickness, fluidity and permeability of fungal cell membranes. These include the azole antifungals, which block ergosterol biosynthesis by inhibiting lanosterol demethylase (Erg11p). The resulting depletion of cellular ergosterol and the accumulation of ‘toxic’ sterol intermediates are both thought to cause plasma membrane dysfunction and ultimately growth arrest. However, the effects of ergosterol depletion upon the function of intracellular membranes and organelles are not well described. The purpose of this study was to characterize the effects of azole treatment upon the integrity of the Candida albicans vacuole, …

Dynamic Host-Pathogen Interactions Result In Fungal Epitope Unmasking, Alex Hopke

Electronic Theses and Dissertations

Molecular camouflage is used by a diverse set of pathogens to disguise their identity and avoid recognition by protective host receptors. The opportunistic fungal pathogen Candida albicans is a good example, as it masks the inflammatory component β-glucan in its cell wall to evade detection by the immune receptor Dectin-1. Interestingly, it has been seen that β-glucan becomes unmasked during infection in vivo, though the underlying mechanisms remained unclear. Exposure levels of this epitope may be important, as Dectin-1 mediates protection from some strains of C. albicans and alterations in the organization and composition of the Candida cell wall …

In Vivo Monitoring Of Therapeutic Efficacy And Virulence Profile By Bioluminescent Klebsiella Pneumoniae., Ramy Ameen Fodah

Electronic Theses and Dissertations

Klebsiella pneumoniae causes an acute respiratory infection in human with severe outcomes and high mortality rates even with antibiotic treatment. Even with its critical clinical importance, few virulence systems have been identified for K. pneumoniae limiting the development of new therapeutic strategies. Accordingly, we performed Next Generation sequencing for the strain ATCC 43816, a virulent strain in mouse respiratory disease models, and compared its genomic data with two previously sequenced strains NTUH-K2044 and MGH 78578 for the purpose of identifying genes required for colonizing host lungs. Furthermore, the virulence potential of the three K. pneumoniae strains were tested in a …

The Role Of Collagen Interacting Proteins In The Pathogenesis Of Filifactor Alocis, Ozioma Salomey Chioma

Loma Linda University Electronic Theses, Dissertations & Projects

Filifactor alocis is a Gram-positive, asaccharolytic; obligate anaerobe that has emerged as a potential periodontal pathogen due to its presence in high numbers in patients who have periodontal disease and least detection in healthy individuals (Kumar et al., 2003, Kumar et al., 2006, Wade, 2011). There is compelling evidence in the literature that demonstrates that F. alocis has virulence properties that may play an important role in infection-induced periodontitis (Abusleme et al., 2013, Griffen et al., 2012, Hutter et al., 2003, Khader et al., 2006, Siqueira and Rocas, 2003, Siqueira et al., 2009). However, there is a gap in our …

Comparative Studies Of Tslp And Il-7 In Normal Early Human Neonatal And Adult B Cell Development, Terry-Ann Milford

Loma Linda University Electronic Theses, Dissertations & Projects

Defining the role of cytokines in promoting human B cell development is important for understanding B cell leukemia and for developing strategies to restore B cell production that is lost during some therapies. The purpose of this study was to investigate the roles of the IL-7R ligands, thymic stromal lymphopoietin (TSLP) and IL- 7, in the early stages of normal postnatal and adult human B cell development. Using novel in vitro and in vivo model systems, we show that TSLP and IL-7 are able to expand B cell precursors individually and in combination from CB hematopoietic stem cells. In this …

Traveling With Stowaways: The Human Microbiome And Travel, Alisha N. Hughes

Global Honors Theses

The human microbiome is a research field that is fairly new and thus, not yet fully understood. However, past research has revealed that the human host and the microorganisms interact with each other. To comprehend how influential the connection between host and its stowaways is, the following text will first offer general information on the human microbiome, before moving on to a pilot case study proposal. With the use of similar case studies, this proposal aims to investigate how the human microbiome changes when the host travels and analyzes the changes and their affects on the individual’s health. The paper’s …

Examination Of Cd133 And Cd147 As Cancer Stem Cell Markers, Christopher Mcmahon

All NMU Master's Theses

To date, as many as 14,000 patients in the United States per year are diagnosed with glioblastoma, the most common and most malignant primary brain tumor. Glioblastomas are characterized by their ability to evade treatment on many fronts, thus a novel approach to curative therapies is imperative. A population of cells with stem cell-like properties are found within glioblastoma tumors and drive their initiation and progression. Identification of extracellular markers on these tumor stem cells is thus paramount. The cell surface glycoproteins CD133 and CD147 were examined as potential markers of cancer stem cells found in glioblastoma. Here we found …

A Novel And Rapid Staphylococcus Aureus Bacterial Identification Method Utilizing Immunomagnetic Beads And Single Cell Laser-Light Scattering, Kaylagh Hollen

All NMU Master's Theses

Staphylococcus aureus is the most commonly isolated human associated bacterial pathogen. It plays an important role in skin and soft-tissue infections, pneumonia, endocarditis, osteomyelitis, foreign-body infections, and sepsis. S. aureus diagnosis and treatment requires a minimum of 24-48. With this in mind, previous studies suggest that faster pathogen identification has been linked to improved patient outcomes. Improved patient outcomes including a reduction in hospitalization time, decreased risk of nosocomial infections, and decreased in medical costs. The impact of faster identification on patient outcome has led us to develop an alternative method of S. aureus identification via ImmunoMagnetic Separation (IMS) and …

Redesigning Gfp Reporter System For Utilization In Clostridium Difficile, Laura E. Fitzgerald

Biological Sciences Undergraduate Honors Theses

Clostridium difficile (C. difficile) is a gram-positive bacterium that comprises part of the healthy human gut microbiome. When it gains sufficient access to peptides, C. difficile flourishes and releases tissue-damaging toxins, which cause inflammation of the colon that can develop into a Clostridium difficile Infection (CDI).¹⁰ The Ivey Laboratory believes that the best tactic in preventing CDIs is stopping peptide ingestion, which theoretically could be accomplished by manipulating the oligopeptide permease (App) system.⁷ In order to verify that altering the App system would successfully impede peptide uptake, first the expression of the app Promoter Region ( …

The Effect Of Increased Exposure Of Uvc Light On Human Skin Microbiota, T'Kylia S. Moss

Honors Theses

Many methods have been employed to prevent infections from opportunistic pathogens in immunocompromised individuals. Among these are the use of ultraviolet light (UV). In this study, UVC light, was found to have a deleterious effect on specific skin flora. Organisms tested included Acinetobacter baumanii, Candida albicans, Candida kefyr, Corynebacterium renale, Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. Nutrient agar was used to cultivate most organisms. Blood agar was used for the cultivation of Streptococcus pyogenes and Enterococcus faecalis. Bacterial suspensions were made and utilized to plate each organism onto a set of 7 nutrient agar or …

Understanding Structural And Functional Mechanisms Of Emi1 Inhibition Of The Anaphase Promoting Complex, Edmond Randall Watson

Theses and Dissertations (ETD)

Healthy, reproducing cells create and destroy proteins in an ordered manner. Both the concentration and localization of protein pools is important to regulate the many cellular processes necessary for the life of the cell. In order to produce new proteins, cells degrade existing materials such as proteins and organelles that are dispensable or troublesome in order to recycle their raw components. Degradation is accomplished largely through two major pathways: in bulk through processes such as autophagy and phagocytosis, or in a targeted manner through the ubiquitin-proteasome pathway. Autophagy utilizes an encompassing body to encapsulate targets and surrounding materials for decomposition …

Porphyromonas Gingivalis Gingipains Induce A Pro-Inflammatory Extracellular Microenvironment : The Role Of Par-2 And Fibronectin., Jeffrey S. Marschall

Electronic Theses and Dissertations

Periodontitis is a chronic inflammatory disease that is characterized by severe tissue destruction of the gingiva and other tooth supporting structures; if left untreated, tooth loss and disintegration of the alveolar bone occurs. This chronic inflammatory state has been linked to other systemic diseases such as cardiovascular disease, diabetes, rheumatoid arthritis, and Alzheimer’s disease. Porphyromonas gingivalis is the major pathogenic microbe in periodontitis. The main virulence factors of P. gingivalis are the Arg-aa and Lys-aa gingipains, which are proteolytic enzymes implicated in a plethora of activities that allow P. gingivalis to subvert the human immune system in the oral cavity …

Oncolytic Virus Therapy For The Treatment Of Metastatic Ovarian Cancer, Jessica Tong

Electronic Thesis and Dissertation Repository

The management of patients with epithelial ovarian cancer (EOC) faces two major challenges which standard treatments fail to effectively address: 1) Diffuse metastasis as a consequence of late stage diagnosis and 2) intra-tumoral heterogeneity, which fuels tumor evolution and drives the acquisition of chemotherapeutic resistance. In this thesis, we tested new therapeutic strategies using a 3-dimensional in vitro spheroid culture model that mimics key steps of epithelial ovarian cancer metastasis; and another model that mimics both temporal and cellular heterogeneity by establishing multiple cell lines from a single patient over the course of disease progression. Using these models, we investigated …

Expression Levels Of Virulence Genes In Group A Streptococci: A Response To Aerosolized Propylene Glycol, Michael S. Costello

Honors Undergraduate Theses

Electronic cigarette usage is becoming increasingly prevalent among school age children and young adults. A known bactericidal agent, propylene glycol, is often used as a carrier for nicotine, flavoring, and additional constituents of electronic cigarette juice. This study examined the relationship between propylene glycol and virulence gene expression in Streptococcus pyogenes, a respiratory tract pathogen commonly found in school-age individuals. A variety of virulence genes controlled by the three stand alone regulators mga, RofA, and Rgg/RopB were sampled in an effort to understand the pathway by which virulence is affected. The genes chosen encode C5a peptidase, fibronectin binding protein, hyaluronate …

Emerging Pathogens In Cystic Fibrosis Patients At Virginia Commonwealth University Medical Center (Vcumc), Emily M. Hill

Theses and Dissertations

Cystic fibrosis (CF) is an autosomal recessive disorder affecting 70,000 individuals worldwide. This disease is characterized by the buildup of mucus in the airways leading to chronic lung infections resulting in pulmonary failure and death in 95% of CF patients. Routine surveillance of CF pathogens using traditional microbiology culture guides management and treatment of CF patients. Molecular profiling studies have revealed emerging pathogens that may play a role in CF lung disease by either directly causing infection or upregulating the virulence factors of classic CF pathogens, such as P. aeruginosa; however, routine CF culture protocols have not been modified …

Antibiotic Efficacy And Interaction In Escherichia Coli During Varying Nutrient Conditions, Kristina K. Millar

Scripps Senior Theses

Due to the recent rise in antibiotic resistant pathogens, and the difficulties surrounding the quest for new antibiotics, many researchers have started revisiting antibiotic interactions in hopes of finding new treatment options. The primary outcome of this project was to examine the efficacy of concomitant antibiotic use under varying nutrient conditions, to identify variations in antibiotic interactions. Antibiotic interactions were studied, utilizing E. coli as a model bacterial system, grown in four different media types. E. coli cultures were treated with streptomycin, tobramycin, erythromycin, and amikacin individually and in a pairwise fashion at varying doses. We found that at least …

Drug And Vaccine Development For Neisseria Gonorrhoeaea, Devin R. Cash

Theses and Dissertations

Neisseria gonorrhoeae, the causative agent of the STI gonorrhea, is not preventable by vaccination and is rapidly developing resistance to antibiotics. One important strategy for gonococcal survival in the host is iron acquisition in the face of nutritional immunity. To overcome iron limitation, the gonococcus expresses TonB dependent transporters (TdTs), outer membrane proteins that facilitate nutrient acquisition. Of the TdTs, the transferrin (Tf), lactoferrin (Lf), and hemoglobin (Hb) receptors hijack iron directly from host proteins, and studies have already shown that the Tf receptor is essential for the initiation of human infection. Given that the TdTs are virulence factors, …

Modulation Of Body Weight By Intestinal Flora In Orphan Nuclear Receptor Shp-/- Mice, Ryan Mifflin

Williams Honors College, Honors Research Projects

The whole-body deletion of small heterodimer partner (SHP) in mice is associated with protection from diet-induced obesity and hepatic steatosis upon feeding of a western diet. This protection was reported to be mediated through decreases in hepatic gene expression for lipogenesis, as well as increases in gene expression for fatty acid oxidation. SHP has been known to regulate the expression of the CYP7A1 gene, encoding the rate-limiting enzyme for bile acid synthesis, thereby altering the bile acid pool. The effects of this altered bile acid profile on the gut microbiome are unknown, as some bacteria in the gut are responsible …

Inhibition Of Bacterial Growth And Prevention Of Bacterial Adhesion With Localized Nitric Oxide Delivery, Julia Osborne

Dissertations, Master's Theses and Master's Reports

Bacterial infections continue to be a problem at the site of an indwelling medical device, and over the years, various bacterial strains have become more resistant to current antibiotic treatments. Bacterial infection at an indwelling medical device can be dangerous and affect the performance of the medical device which can ultimately lead to the failure of the device due to bacterial resistance to treatment.

Nitric Oxide (NO) has been shown to possess antibacterial properties to prevent and inhibit bacterial growth. NO releasing coatings on indwelling medical devices could provide a reduction in bacterial infections that occur at the device site …