Microbiology Commons^™

Characterization Of Transfer Of The Mobile Genomic Island Encoding Methicillin Resistance Among Staphylococci, Melissa D. Ray

Theses and Dissertations

The gene encoding methicillin resistance in Staphylococcus aureus (MRSA) is carried in the chromosome on a large genomic island called SCCmec and is always inserted at the att site within orfX. SCCmec has been designated a mobile genetic element but a mechanism by which it moves among different strains and species of staphylococci has never been demonstrated. This work shows that bacteriophage 80α is capable of transducing SCCmec into a recipient cell, after which it can integrate into the bacterial chromosome via homologous recombination. More importantly, this work characterizes a conjugative mechanism of SCCmec transfer. …

The Characterization Of A Putative Virulence Factor Expressed By Sneathia Amnii, Amy Sanford

Theses and Dissertations

Preterm birth, defined at birth before 37 weeks gestation, affects millions of newborns worldwide every year. Preterm birth is a leading cause of infant morbidity and mortality. One major cause of preterm birth is preterm premature rupture of membranes (PPROM), which can be triggered by bacterial infection and inflammation. A bacterial species that has been implicated in preterm birth and other obstetric complications is Sneathia amnii. The goals of this study were to observe cytopathogenic effects caused by S. amnii strain Sn35 and identify putative virulence factors causing those effects. Sn35 was able to adhere to, invade, and damage/kill …

A Novel Antimicrobial Drug Discovery Approach For The Periodontal Pathogen Porphyromonas Gingivalis, Victoria N. Stone

Theses and Dissertations

The human body is colonized by more than 100 trillion microbes which make up an essential part of the body and plays a significant role in health. We now know the over use and misuse of broad-spectrum antibiotics can disrupt this microbiome contributing to the onset of disease and runs the risk of promoting antibiotic resistance. With antibiotic research still on the decline, new strategies are greatly needed to combat emerging pathogens while maintaining a healthy microbiome. We therefore set out to present a novel species-selective antimicrobial drug discovery strategy.

Disruption of the homeostasis within the oral cavity can trigger …

Orientia Tsutsugamushi Ankyrin-Repeat Protein Family Targeting Of The Host Endoplasmic Reticulum, Lauren Viebrock

Theses and Dissertations

Abstract

ORIENTIA TSUTSUGAMUSHI ANKYRIN REPEAT-PROTEIN FAMILY TARGETING OF THE HOST ENDOPLASMIC RETICULUM

By Lauren VieBrock, B.S.

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University

Virginia Commonwealth University, 2015

Director: Jason A. Carlyon, Ph.D.

Professor

Microbiology and Immunology

Scrub typhus is an understudied, potentially fatal febrile illness, which poses threat to one billion people annually in the Asia-Pacific region. The host-pathogen interactions that facilitate the intracellular survival of the etiologic agent, Orientia tsutsugamushi, are not well understood. The Orientia tsutsugamushi genome encodes a large number of ankyrin repeat-containing proteins …

Mysteries Of The Trypanosomatid Maxicircles: Characterization Of The Maxicircle Genomes And The Evolution Of Rna Editing In The Order Kinetoplastida, Preethi Ranganathan Iyengar

Theses and Dissertations

The trypanosomatid protists belonging to Order Kinetoplastida are some of the most successful parasites ever known to mankind. Their extreme physiological diversity and adaptability to different environmental conditions and host systems make them some of the most widespread parasites, causing deadly diseases in humans and other vertebrates.

This project focuses on their unique mitochondrion, called the kinetoplast, and more specifically involves the characterization of a part of their mitochondrial DNA (also called kinetoplast DNA or kDNA), the maxicircles, which are functional homologs of eukaryotic mitochondrial DNA in the kinetoplastid protists. We have sequenced and characterized the maxicircle genomes of 20 …

Integrated Nanoscale Imaging And Spatial Recognition Of Biomolecules On Surfaces, Congzhou Wang

Theses and Dissertations

Biomolecules on cell surfaces play critical roles in diverse biological and physiological processes. However, conventional bulk scale techniques are unable to clarify the density and distribution of specific biomolecules in situ on single, living cell surfaces at the micro or nanoscale. In this work, a single cell analysis technique based on Atomic Force Microscopy (AFM) is developed to spatially identify biomolecules and characterize nanomechanical properties on single cell surfaces. The unique advantage of these AFM-based techniques lies in the ability to operate in situ (in a non-destructive fashion) and in real time, under physiological conditions or controlled micro-environments.

First, AFM-based …

Infection And Dissemination Of Tav-Gfp Tagged Sindbis In Aedine Mosquitoes And Cell Lines, Jason J. Saredy

UNF Graduate Theses and Dissertations

Arthropod-borne-viruses (arboviruses) pose a global threat due to their ability to be transmitted by hematophagous insects to vertebrate hosts resulting in a range of serious infectious diseases. Sindbis virus (SINV) is the prototype arbovirus of the genus Alphavirus in the family Togaviridae. The purpose of this study was to investigate the use of a fluorescent tagged reporter virus in both in vitro and in vivo environments. The fluorescent protein GFP was inserted between the Capsid and PE2 in the genome of TR339; SINV TaV-GFP (Wm. Klimstra Lab). This virus construct should have the same infectivity and virulence as wild type …

Clinical Isolates Of Salmonella Enterica Serovar Agona Producing Ndm-1 Metallo-Beta-Lactamase: First Report From Pakistan, Seema Irfan, Erum Khan, Kauser Jabeen, Pushpa Bhawan, Katie L. Hopkins, Martin Day, Amna Nasir, Daniele Meunier, Neil Woodford

Department of Pathology and Laboratory Medicine

We report two cases of infantile diarrhea due to multidrug-resistant, NDM-1 metallo-beta-lactamase-producing Salmonella enterica serovar Agona from Pakistan. This study alerts toward possible risk of NDM-1 transmission to enteric fever pathogens and encourages microbiologists to consider active screening of carbapenem resistance in nontyphoidal Salmonella isolates.

Gastrointestinal Stromal Tumors: A Clinicopathologic And Risk Stratification Study Of 255 Cases From Pakistan And Review Of Literature, Nasir Ud Din, Zubair Ahmad, Huma Arshad, Romana Idrees, Naila Kayani

Department of Pathology and Laboratory Medicine

Purpose:
To describe the clinicopathological features of gastrointestinal stromal tumors (GIST) diagnosed in our section and to perform risk stratification of our cases by assigning them to specific risk categories and groups for disease progression based on proposals by Fletcher et al and Miettinen and Lasota.
Material and Results:
We retrieved 255 cases of GIST diagnosed between 2003 and 2014. Over 59% were male. The age range was 16 to 83 years with a mean of 51 years. Over 70% occurred between 40 and 70 years of age. Average diameter of tumors was 10 cms. The stomach was the most …

Hiv Prevalence In Blood Donors And Recipients In Pakistan: A Meta-Analysis And Analysis Of Blood-Bank Data, Bushra Moiz, Barkat Ali, Muhammad Hasnain Chatha, Ahmed Raheem, Hasan Abbas Zaheer

Department of Pathology and Laboratory Medicine

Background:
The first instances of HIV-antibody detection in donated blood in Pakistan were reported in 1988. Since then, documentation of HIV in blood donors and of rates of transmission via transfusion has been limited. Previously assumed to have a low prevalence, HIV is an increasing health concern in Pakistan. Since there is no national, centralized blood-banking system, there are no reliable data on which to base estimated risks of transfusion-associated HIV infection. This study was therefore conducted to estimate the prevalence of HIV in blood donors and recipients in Pakistan between 1988 and 2012.
Methods:
Meta-analyses were undertaken of reported …

Mammary-Type Myofibroblastoma Of The Right Thigh: A Case Report And Review Of The Literature, Jamshid Abdul-Ghafar, Nasir Ud Din, Zubair Ahmad, Steven D. Billings

Department of Pathology and Laboratory Medicine

Introduction:
Mammary-type myofibroblastoma of the soft tissue is a very rare, benign, mesenchymal neoplasm with myofibroblastic differentiation. To date, 20 cases of extra-mammary myofibroblastoma have been described in literature. To the best of our knowledge, this is the largest extra-mammary myofibroblastoma described in the literature, and the first case reported in this location.
Case Presentation:
A 50-year-old Pakistani man presented with a long history of a painless, huge lump on his right thigh. His clinical examination showed normal-looking skin and there was no inguinal lymphadenopathy. The mass was excised with a clinical impression of soft tissue sarcoma. Gross examination showed …

Characterization Of The Ecological Role Of Genes Mediating Acid Resistance In Lactobacillus Reuteri During Colonization Of The Gastrointestinal Tract, Janina A. Krumbeck, Nathan L Marsteller, Steven Frese, Daniel A. Peterson, Amanda Ramer-Tait, Robert W. Hutkins, Jens Walter

Department of Food Science and Technology: Faculty Publications

Rodent-derived strains of Lactobacillus reuteri densely colonize the forestomach of mice and possess several genes whose predicted functions constitute adaptations towards an acidic environment. The objective of this study was to systematically determine which genes of L. reuteri 100-23 contribute to tolerance towards host gastric acid secretion. Genes predicted to be involved in acid resistance were inactivated, and their contribution to survival under acidic conditions was confirmed in model gastric juice. Fitness of five mutants that showed impaired in vitro acid resistance were then compared through competition experiments in ex-germ-free mice that were either treated with omeprazole, a proton-pump inhibitor …

Unveiling Novel Aspects Of D-Amino Acid Metabolism In The Model Bacterium Pseudomonas Putida Kt2440, Atanas D. Radkov

Theses and Dissertations--Plant and Soil Sciences

D-amino acids (D-AAs) are the α-carbon enantiomers of L-amino acids (L- AAs), the building blocks of proteins in known organisms. It was largely believed that D-AAs are unnatural and must be toxic to most organisms, as they would compete with the L-counterparts for protein synthesis. Recently, new methods have been developed that allow scientists to chromatographically separate the two AA stereoisomers. Since that time, it has been discovered that D-AAs are vital molecules and they have been detected in many organisms. The work of this dissertation focuses on their place in bacterial metabolism. This specific area was selected due to …

Efficacy Of Ultraviolet Radiation To Control Lactic Acid Bacteria In Wine Must, Brian D. Williams

All Master's Theses

The use of shortwave ultraviolet (UV_c) radiation to control lactic acid bacteria (LAB) in wine production was studied. A simulated wine sterilizer was built using a commercially sourced ultraviolet (UV) sterilizer commonly used in aquariums and ponds. After growing cultures in test tubes, samples of five different species of LAB were introduced into white grape juice adjusted for brix and pH to match that of wine must commonly found in the Yakima Valley American Viticultural Area. The mixture was then agitated and allowed time to evenly distribute the bacteria throughout the juice. The juice was sent through the …

Effects Of Treated Wastewater Effluent On Microbial Community Structure In A Natural Receiving Aquatic System, Matthew D. Hladilek

Masters Theses

Despite our dependency on treatment facilities to condition wastewater for eventual release to the environment, our knowledge regarding the effects of treated water on the local watershed is extremely limited. Responses of these lotic systems to the treated wastewater effluent have been traditionally investigated by examining the benthic macroinvertebrate assemblages and community structure; however, these studies do not address the microbial diversity of the water systems. In the present study, planktonic and benthic bacterial community structure were examined at fourteen sites (from 60 m upstream to 12,100 m downstream) and at two time points along an aquatic system receiving treated …

Metagenomic Analysis Of The Lacrimal Caruncle Region Of Canis Lupus Familiaris Using Miseq Technology, Seun A. Ikugbayigbe

Masters Theses

The identification of ocular microbiota may allow early diagnosis and treatment strategies against eye diseases and disorders with canines. However, clinical microbial identification has been limited to cloning and conventional culture-based studies, which typically underestimate community diversity. In this report, lllumina MiSeq analysis of the 16S rRNA gene was used to examine the microbiome of the lacrimal caruncle region from five healthy dogs. The breeds sampled were a Golden Retriever (Dog A), a Weimaraner (Dog B), a Shih Tzu mix (Dog C), a Yorkie mix (Dog D), and a Dachshund (Dog E). MiSeq analysis revealed a total of 370 operational …

Household Biosand Water Filters: Materials, Capacity, And Temperature Effects On Performance, Nathan B. Arnold

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

The household biosand filter (BSF) is one of the world’s most utilized point-of-use (POU) water treatment tools where drinking water is not reliably potable. The feasibility of using ferrocement for construction, the filter volume, and the effect of temperature on removal are unclear, however. The following field and laboratory research was carried out in Panama and at Michigan Technological University. Field testing of ferrocement biosand filters (FBSFs) in rural Panama yielded average coliform and E.coli removals that compared favorably to plastic and cement BSFs. Parallel testing of a larger-bodied FBSF and a conventionally-sized BSF revealed that the former is necessary …

Herpes Virus Infections, Inflammatory Markers And Risk Of Developing T2dm And Cvd: An Analysis Of Nhanes With Adults, Aged 20-49, 1999-2010, Margarita Irizarry-De La Cruz

Walden Dissertations and Doctoral Studies

Herpes simplex viruses (HSVs), are among the most virulent and widespread pathogens; they affect 60-90% of the population worldwide. Substantial evidence indicates a possible association between pathogens and chronic disease. HSVs, among other viruses, have been associated with increased risk for inflammatory diseases. However, prior findings have been inconsistent on the role of infection in triggering autoimmune response and chronic disease. This study builds on the premise that pathogens can induce an inflammatory response and increase the risk for disease development. A representative U.S. sample from NHANES, a national population-based cross-sectional survey, was used to examine the relationship between HSVs …

Exploratory Study Of Seasonal Indoor Bioaerosols And The Associated Health Outcomes In Low-Income Communities In El Paso, Texas, 2014, Eric Martinez

Open Access Theses & Dissertations

Introduction: Structural degradation, moisture levels, and building failures can influence poor indoor air quality and create a good environment for bioaerosols. People spend much of their time indoors and can potentially be exposed to these bioaerosols. Several studies have correlated exposures to high concentrations of bioaerosols to various health problems, severe allergies, asthma, or other respiratory illness. Objectives: The objectives of this study are to describe bioaerosol concentrations, meteorological factors, and health outcomes during the summer and fall seasons; characterize bioaerosols (bacteria and fungi) collected in low-income communities; compare bioaerosol concentrations by season; compare meteorological factors to bioaerosol concentrations by …

The Role Of Pidd Protein In Adenoviral Induction Of Apoptosis, Iris Teresa Figueroa

Master's Theses

The Adenovirus E1A gene sensitizes cells to genetic insults and apoptosis, most notably in response to cytotoxic factors from innate immune cells. The mechanisms by which E1A sensitizes cells to apoptotic stressors have not been fully elucidated, however E1A actively represses NF-κB anti-apoptotic defenses, thereby sensitizing cells to alternative apoptotic cascades. Recent studies alternatively indicate that E1A also actively induces Caspase-2 activation and mitochondrial injury in the presence of certain cytotoxic injuries.

Caspase-2 is cleaved and activated in a large complex consisting of p53-inducible protein with a death domain (PIDD), an adaptor protein RAIDD, and pro-caspase 2. PIDD auto-proteolyzes into …