Microbiology Commons^™

Using A One Health Approach For The Assessment Of Rabies Control In Rural Victoria Falls, Zimbabwe, Ryan Lapenna

Electronic Thesis and Dissertation Repository

Rabies, a viral zoonotic disease, is widespread in Zimbabwe, with human fatalities reported annually in the country. To supplement the Government’s effort on rabies control, the Victoria Falls Wildlife Trust and Veterinarians for Animal Welfare Zimbabwe have joined forces to carry out dog rabies vaccinations in rural communities adjacent to the major tourist attraction of The Victoria Falls. A One Health approach was used to 1) determine the level of protective rabies antibodies among a sample of rural dogs and 2) collect information and describe the knowledge, attitudes, and practices related to rabies among dog owners. In 2020, blood was …

The Role Of Coagulase-Negative Staphylococcal Secreted Products On Staphylococcus Aureus And Staphylococcus Lugdunensis Infections, Denny Chin

Electronic Thesis and Dissertation Repository

The Staphylococcus genus is comprised of over 40 bacterial species. The most well-studied species in this genus is the notorious human pathogen Staphylococcus aureus, a bacterium that produces coagulase among many other virulence factors. Since S. aureus is a major health burden and causes a plethora of diseases in humans, it has received significant attention and much research has been done to understand its biology to treat diseases caused by this pathogen. However, the coagulase-negative staphylococci (CoNS) make up most of the staphylococcal species and have received less attention since they are thought to have a lesser impact on …

Fishing For The Right Probiotic: Investigating The Mechanism Of Mucosal-Bacterial Interactions At The Interface Of Health And Productivity In Salmonid Aquaculture, Luana Langlois

Electronic Thesis and Dissertation Repository

Aquaculture is vital for the global food supply, but the high incidence of infectious diseases threatens the industry’s productivity. The intestinal mucosa is a key port of entry for pathogens and provides an extensive interface for host-microbe interactions. Tight junctions are at the core of gut barrier function and the mucosal health of finfish. Disruption of these complexes gives rise to sepsis, which leads to systemic inflammation and death. The present study employs a combinatorial approach that integrates in vitro and in vivo analyses to gain actionable insights into the mechanism of microbial-mediated modulation of host health. The experiments outlined …

Hiv-1 Drug Resistance To Integrase Strand Transfer Inhibitors In Hiv-1 Non-B Subtypes, Emmanuel Ndashimye

Electronic Thesis and Dissertation Repository

Human immunodeficiency syndrome (HIV-1) has infected over 75 million people and over 35 million have succumbed to virus related illnesses. Despite access to a variety of antiretroviral therapy (ART) options, ART programs have been disproportionally spread in the world with low-and middle-income countries (LMICs) facing challenges to access the most potent ART options. With less potent ART remaining in use in LMICs, HIV-1 drug resistance (HIVDR) presents a growing challenge in LMICs. Since approval of the first-generation integrase strand transfer inhibitor (INSTIs), Raltegravir (RAL) in 2007, INSTIs remain the best choice as a backbone of ART. Access to second generation …

Utilizing Fiv (Feline Immunodeficiency Virus) To Develop A Novel Animal Model To Study Hiv (Human Immunodeficiency Virus), Ankita Suryakant Kambli

Electronic Thesis and Dissertation Repository

This project sought to perform the in vitro work needed to accomplish the long-term vision of harnessing the similarities between HIV (Human Immunodeficiency Virus) and FIV (Feline Immunodeficiency Virus) to develop an animal model whereby cats can be used to study HIV pathogenesis and therapeutics. We transfected CRFK (Crandell Rees Feline Kidney) fibroblasts with plasmids that could express human or feline CD4, CCR5, or both, and determined receptor surface expression through flow cytometry. We discovered that HIV envelope expressed on 293T can fuse with huCD4/huCCR5 on CRFK. These cat cell lines were also capable of supporting HIV infection. Additionally, we …

Determining The Relative Transmission Fitness Of Hiv-1 Subtypes A, B, C, And D, Spencer Yeung

Electronic Thesis and Dissertation Repository

There is in vivo evidence that suggests the genetic diversity of HIV-1 subtypes influence heterosexual transmission efficiency. To recapitulate sexual transmission in vitro, blocks of genital tissue were exposed to mixtures of genetically different subtype viruses. Migrating immune cells were collected and co-cultured with a CD4+ T-cell line permissive to HIV infection (PM1) to measure dendritic cell virus transfer; HIV-exposed tissues were cultured separately. Next generation sequencing (NGS) of HIV-1 DNA was used to quantify relative infection rates of the various challenge viruses, and to assess fitness differences in infection of the tissue vs. migratory/T cell co-cultures. Our results …

Hiv-1 Group M Subtype Fitness, Disease Progression, And Entry Efficiency, Colin M. Venner

Electronic Thesis and Dissertation Repository

Human immunodeficiency virus type 1 (HIV-1) emerged in the human population shortly after the turn of the 19th century. Distribution of HIV-1 across the globe over the past 30–35 years can be traced to founder events with primordial HIV strains from sub-Saharan Africa. Even considering the burden of HIV in Africa, our knowledge of HIV-1 disease is still largely limited to subtype B HIV-1, a strain responsible for 3 million infections in North America and Europe as compared to the 33 million that are infected with HIV-1 subtypes A, C, D, and circulating and unique recombinant forms.

This dissertation analyzes …

The Group A Streptococci Bacteriocins Facilitate A Competitive Advantage During Nasopharyngeal Infection, Lana Estafanos

Electronic Thesis and Dissertation Repository

Pathogenic streptococci have evolved specific systems to eliminate bacterial competitors within their biological niche. In microbial environments, niche competition is often driven by the production of short antimicrobial peptides called bacteriocins; this provides a mechanism by which Streptococcus pyogenes may compete for ecological stability and establish infection. Recent findings from our laboratory have identified two novel Class IIb bacteriocin systems – Streptococcus pyogenes bacteriocin (Spb) JK and MN in the M18 serotype S. pyogenes strain MGAS8232 – that may contribute to nasopharyngeal infection. Here, we show that galactose and CO₂ are distinct regulatory cues which induce antimicrobial activity. Under …

Understanding The Impact Of Hiv-1 Genetic Diversity On The Function Of Nef And Its Role In Serinc5 Antagonism, Aaron Leslie Johnson

Electronic Thesis and Dissertation Repository

HIV-1 Nef is a key pathogenic protein, allowing HIV-1 to evade the host immune system by downregulating MHC-I and CD4. Furthermore, it was recently discovered that Nef counteracts the host factor SERINC5 to increase HIV-1 infectivity, but the mechanistic details of the Nef:SERINC5 interaction still need to be explored. Throughout this dissertation, I will explore the hypothesis that the genetic diversity that defines HIV-1 has a pronounced effect on the HIV-1 protein Nef, altering its function between and within group M subtypes. To address this hypothesis I investigated how MHC-I and CD4 downregulation differ among all non-recombinant group M subtypes. …

Granulocyte Colony-Stimulating Factor: Its Role In Gut-Homing Macrophage Generation And Colitis, And Production By Probiotics, Shahab Meshkibaf

Electronic Thesis and Dissertation Repository

The pleiotropic cytokine granulocyte-colony stimulatory factor (G-CSF) is mainly required for the generation of neutrophils, but its role in macrophage generation has also been reported. In addition, G-CSF is effective for the down-regulation of inflammatory cytokines and ameliorating gut disorders, such as colitis. However, the G-CSF function in macrophage generation and gut immunity remains unclear. The first focus of this thesis was to assess the role of G-CSF in macrophage generation and its contribution to gut immunity. G-CSF was found to promote the generation of Gr-1high/F4/80+ macrophages in macrophage (M)-CSF-treated bone marrow cells, most likely through suppressing cell death. Gr-1high …

Genomic Predictors Of Drug Response To The Alpha-Specific Phosphoinositol 3-Kinase (Pi3ka-Alpha) Inhibitor Byl719 In Head And Neck Cancers, Giananthony T. Rizzo

Electronic Thesis and Dissertation Repository

PIK3CA is the only frequently mutated, druggable oncogene in head and neck squamous cell cancer (HNSCC), with PIK3CA point mutations and gene amplification rates of 17.5% and 40% respectively, with higher rates in HPV-positive disease. The objective of this research was to determine the effects of BYL719, an α-specific PI3K inhibitor in HNSCC cell lines.

All cell lines with PIK3CA hotspot point mutations or gene amplifications will be sensitive to BYL719.

Twenty-eight HNSCC cell lines were subjected to increasing concentrations of BYL719 and cell viability was measured over time. Cell lines were screened for activating PIK3CA hotspot mutations and amplifications …

Probiotic Therapy For Heart Failure: Investigating The Potential Anti-Hypertrophic Properties Of Probiotics, Grace L. Ettinger

Electronic Thesis and Dissertation Repository

Heart failure patients face a five-year 50% mortality rate, due to impaired cardiac function and hypertrophy of the heart. Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Considering the established cardiovascular benefits of some probiotics, including reduction of cholesterol and hypertension, it was hypothesized that probiotics can improve outcomes of heart failure. Probiotics or controls were administered orally to an animal model for heart failure. Those receiving probiotics showed a significant improvement in cardiac hypertrophy and an attenuation of heart failure compared to control. No changes in gut microbial composition occurred. …

Characterizing The Human Vaginal Microbiome Using High-Throughput Sequencing, Jean Megan E. Macklaim

Electronic Thesis and Dissertation Repository

The human vaginal microbiome undoubtedly has a significant role in reproductive health and for protection from infectious organisms. Recent efforts to characterize the bacterial species of the vagina using molecular techniques have uncovered an unexpected diversity. Using high-throughput sequencing I sought to describe the structure and function of the vaginal microbiome under different physiological states including healthy, bacterial vaginosis (BV), post-menopausal vaginal atrophy, and acute vulvovaginal candidiasis (VVC).

Partial 16S rRNA gene sequencing revealed that healthy, asymptomatic women most often have vaginal biotas dominated by Lactobacillus iners or L. crispatus. In contrast, BV is a heterogeneous, highly diversified condition …

Human Adenovirus E1a Binds And Retasks Cellular Hbre1, Blocking Interferon Signalling And Activating Virus Early Gene Transcription, Gregory J. Fonseca

Electronic Thesis and Dissertation Repository

Upon infection, human adenovirus (HAdV) must block interferon signaling and activate the expression of its early genes to reprogram the cellular environment to support virus replication. During the initial phase of infection, these processes are orchestrated by the first HAdV gene expressed during infection, early region 1A (E1A). E1A binds and appropriates components of the cellular transcriptional machinery to modulate cellular gene transcription and activate viral early genes transcription. We have identified hBre1/RNF20 as a novel target of E1A. hBre1 is an E3 ubiquitin ligase which acts with the Ube2b E2 conjugase and accessory factors RNF40 and WAC1 to monoubiquitinate …

Restriction Of Hiv-1 Replication By Unique Trim22 Isoforms., Clayton Hattlmann

Electronic Thesis and Dissertation Repository

Understanding how the immune system reacts to HIV infection and why normal antiviral defenses are insufficient to fight infection is a key step towards creating better therapies. Several interferon-induced proteins, such as the tripartite motif protein TRIM22, are capable of restricting HIV-1 replication; however single nucleotide polymorphisms (SNPs) can dramatically impact the actions of these proteins. While the trim22 gene contains numerous SNPs, no study has addressed how these may affect TRIM22 functions. Here we provide the first direct comparison of two TRIM22 unique isoforms. Through confocal microscopy we observed these isoforms exhibit different patterns of localization. In vitro studies …