Microbiology Commons^™

Next-Generation Sequencing Of A Multi-Drug Resistance Plasmid Captured From Stream Sediment, Kevin G. Libuit

Masters Theses, 2010-2019

Plasmids in agriculturally-impacted bodies of water may play a significant role in the dissemination of antibiotic resistance. Previously, Erika Gehr, as part of her M.S. thesis work in our laboratory, captured environmental plasmids without cultivation of host bacteria from stream sediment into Escherichia coli. Individual plasmids were capable of conferring resistance to a surprising array of antibiotics including aminoglycosides and extended-spectrum β-lactams. In this study, we developed a method to sequence multi-drug resistance plasmids using both Oxford Nanopore MinION and Ion Torrent Personal Genome Machine sequencers. Plasmid pEG1-1 was sequenced on both platforms and a hybrid assembly utilizing data …

A Single Exercise Bout Enhances The Manufacture Of Viral-Specific T-Cells From Healthy Donors: Implications For Allogeneic Adoptive Transfer Immunotherapy, Guillaume Spielmann, Catherine Bollard, Hawley Kunz, Patrick J. Hanley, Richard J. Simpson

Pediatrics Faculty Publications

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections remain a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). The adoptive transfer of donor-derived viral-specific cytotoxic T-cells (VSTs) is an effective treatment for controlling CMV and EBV infections after HSCT; however, new practical methods are required to augment the ex vivo manufacture of multi-VSTs from healthy donors. This study investigated the effects of a single exercise bout on the ex vivo manufacture of multi-VSTs. PBMCs isolated from healthy CMV/EBV seropositive participants before (PRE) and immediately after (POST) 30-minutes of cycling exercise were stimulated with CMV (pp65 and …

Characterization Of Induced Rnai Silencing Of Vaccinia Virus Essential Genes, Kewa Jiang

University Scholar Projects

Vaccinia virus (VACV) is a large double-stranded DNA virus and the prototypical member of the family Poxviridae and is most notable for its use as the vaccine that eradicated smallpox (variola virus). More recently, VACV has been used to develop recombinant vaccines and immunotherapies. However, many of these processes require VACV replication to be tightly controlled. RNA interference (RNAi) is a powerful tool for in vitro silencing of mRNAs that are complimentary to 19-21 base pairs (bp) of double-stranded RNA (dsRNA). This project outlines the design and preliminary analysis of two inducible RNAi silencing constructs targeting multiple VACV essential genes …

Engineering A Mutation In The Heparin Binding Pocket Of The Human Fibroblast Growth Factor, Roshni Patel

Chemistry & Biochemistry Undergraduate Honors Theses

Fibroblast growth factors (FGFs) are family of proteins that belong to a group of growth factors that are found in mammals and play an important role in angiogenesis, differentiation, organogenesis, and tissue repair. In summary, their main functionality is involved in cell division and proliferation. Because FGFs plays such a vital role in cell proliferation, they are mainly involved in the process of wound healing and injuries. FGF binds to its ligand, heparin—a heavily sulfated glycosaminoglycan. The binding of heparin to FGF occurs through electrostatic interactions, specifically between the negatively charged sulfate groups on heparin and positively charged residues such …

Exploring The Mechanisms Of Action Of Antifungal Peptides Using Saccharomyces Cerevisiae., Michelle L. Mason

Biological Sciences Undergraduate Honors Theses

Candida albicans is a normal inhabitant of the skin and mucosal membranes of humans, however, in individuals with depressed immune systems or disrupted cutaneous flora, Candida can overgrow and cause serious infection. Candida infection is the fourth leading cause of nosocomial infection in the United States. These infections are often associated with longer hospital stays and higher mortality. Current drug therapies for this infection are largely ineffective due to the increased drug resistance of Candida species, and for some therapeutics, high levels of drug toxicity to humans. Histatin 5 is a naturally occurring salivary peptide that has strong antifungal properties. …

The Ccaat-Binding Factor Dependent Regulation Of The Oxidative Stress Response In Candida Albicans, Ananya Chakravarti

Graduate Theses and Dissertations

The success of Candida albicans as an opportunistic human pathogen has been attributed to several factors, including the ability to survive in limiting iron environments and the ability to evade the respiratory burst of human macrophages and neutrophils. The goal of this research is to elucidate the role of the CCAAT-binding factor in the oxidative stress response of Candida albicans. Prior whole genome microarray studies performed in our lab compared the gene expression of a wild type Candida albicans strain versus a hap5Δ strain under iron-limiting growth conditions. Among the differentially regulated genes, CTA1, encoding catalase, had a four-fold higher …

Dissemination And Persistence Of Plasmid Located, Integron Associated Antibiotic Resistant Genes In Wastewater Treatment Plant Effluent And Stream Water Bacteria, _ Suhartono

Graduate Theses and Dissertations

Transmissible plasmid-mediated integrons play important role in the persistence and dissemination of antibiotic resistance throughout the environment. Plasmids from 139 multi-antibiotic resistant Escherichia coli recovered from wastewater treatment plant effluent and upstream and downstream receiving stream water in Northwest Arkansas were extracted and profiled. Genes of class 1 and class 2 integrase (intI), mobilization (mob), sulfamethoxazole resistance (sul), and trimethoprim resistance (dfr) were detected using PCR and confirmed through DNA sequencing. Plasmids from almost half of the isolates (47%) were transmissible with mobF12 gene as the most frequently detected mobilization gene. Plasmid-borne class 1 with and without class 2 integrons …

Alzheimer's Disease: The Silver Tsunami Of The 21st Century, Ankita Sarkar, Madison Irwin, Aditi Singh, Matthew Riccetti, Amit Singh

Biology Faculty Publications

Alzheimer's disease (AD), a fatal progressive neurodegenerative disorder, has no cure to date. One of the causes of AD is the accumulation of amyloid-beta 42 (Aß42) plaques, which result in the onset of neurodegeneration. It is not known how these plaques trigger the onset of neurodegeneration. There are several animal models developed to (i) study etiology of disease, (ii) look for genetic modifiers, and (iii) identify chemical inhibitors that can block neurodegeneration and help to find cure for this disease. An insect model of Drosophila melanogaster has also provided new insights into the disease. Here we will discuss the utility …

The Effect Of Transformed Escherichia Coli On The Mouse Intestine Microbiome: The Microbial Metabolic Enhancement Hypothesis, Bryar P. Kader

Senior Honors Theses

Metabolic disorders affect around thirty-four percent of the population in the United States. Among these disorders is lactose intolerance, which results from diminished production of the human lactase enzyme. This disorder and others like it are genetically determined and cannot be cured. However, the use of transformed bacteria implanted in the colon may provide a means by which the faulty pathway can be bypassed. To test whether transformed bacteria have the capability to aid in the digestion of normally indigestible compounds, a transformed strain of Escherichia coli overexpressing the beta-galactosidase enzyme encoded by the lacZ gene was colonized in the …

The Efficacy Of Zinc And Manganese In Controlling Methicillin-Resistant Staphylococcus Aureus Wound Infections In Vitro, Patrick B. Lau

Honors Scholar Theses

The emergence of Methicillin-Resistant Stapylococcus aureus has triggered an increased interest in finding alternative natural antimicrobials to control the pathogen and combat growing antibiotic resistance. This study investigated the antimicrobial effect of two naturally occurring essential minerals, zinc (Zn) and manganese (Mn) on MRSA for potential application in wound infections. The sub inhibitory concentration (SIC) and minimum inhibitory concentration (MIC) of Zn and Mn against MRSA were determined. The effect of MIC and 2x MIC of Zn and Mn in increasing MRSA susceptibility to oxacillin, and the effect of SIC and MIC of these minerals on MRSA cell adherence and …

Oxidative Stress Response In Archaea: Elucidation Of Oxidant Sensing And Tolerance Mechanisms In Methanosarcina Acetivorans, Matthew Edward Jennings

Graduate Theses and Dissertations

Methanogens are archaea possessing a conserved metabolic pathway which produces methane. Many of the enzymes in the methanogenesis pathway are Fe-S proteins, meaning methanogens are sensitive to conditions which disrupt Fe-S clusters. Molecular oxygen is capable of disrupting Fe-S clusters through oxidation of the iron atoms. Furthermore, reduced iron can facilitate the production of reactive oxygen species (ROS), meaning methanogens must possess antioxidant mechanisms. Detection and eradication of ROS is important for all cells, due to the potentially fatal consequences of unchecked oxidation. This dissertation presents two separate projects investigating mechanisms the model methanogen Methanosarcina acetivorans possess for dealing with …

Stabilization Of Gp120 Outer Domain For Hiv-1-1 Vaccine Immunogen Design, Duoyi Hu

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

The sole envelope glycoprotein spike on the surface of Human Immunodeficiency Virus (HIV-1) is composed of two subunits: gp120 and gp41. The gp120 consists of three domains: the inner domain, outer domain and bridging sheet, to which the viral primary receptor CD4 binds and induces a conformational change in gp120 to expose the co-receptor binding site. Previous studies have found that the outer domain of gp120 is relatively more stable than the inner domain and bridging sheet. When superimposed, the co-crystal structures of CD4-gp120 complex and VRC01-gp120 complex revealed that the CD4-binding site (CD4-BS) antibody VRC01 actually mainly bound to …

Prevalence And Distribution Of Gastrointestinal Nematode Parasites And Dung Beetles Associated With Upland And Lowland Grazing Of Irish Native Dexter Cattle, Noel Dineen

Theses

Diseases such as parasitic gastroenteritis are very common in cattle and can have detrimental economic consequences on agricultural productivity. This study was conducted to establish the prevalence and distribution of gastrointestinal nematode parasites associated with Dexter cattle under an organic lowland grazing regime and an extensive upland system. A secondary aim to the study was to investigate dung beetle assemblages in upland and lowland sites and their interactions with gastrointestinal nematode parasites as they offer an alternative method of natural control to organic farming systems in particular.

Cattle weights were recorded and faecal samples were collected at the beginning and …

Lignocellulose As Carbon Source Promotes Bacterial Synergism And Reduces Antagonism, Yijie Deng

Dissertations

Lignocellulose decomposes slowly in nature because it consists of complex polymers resistant to enzymatic degradation by most organisms. Some bacteria are capable of producing cellulolytic enzymes but the way in which bacteria interact within a community to enhance degradation of the recalcitrant substrate is poorly understood. A better understanding of how bacterial interactions affect lignocellulose degradation would provide potential approaches to improve the efficiency of lignocellulose degradation for biofuel production.

To study whether bacterial interactions enhance lignocellulose degradation, I grew environmental bacterial isolates in mixed cultures and pure cultures. I found that bacterial synergism in mixed cultures was common in …

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 …

Affinity Cryo-Electron Microscopy: Methods Development And Applications, Guimei Yu

Open Access Dissertations

Single particle cryo-electron microscopy (cryo-EM) is an emerging powerful tool for structural studies of macromolecular assemblies. Although less concentrated and smaller amounts of samples are required for single particle cryo-EM compared to X-ray crystallography, it remains challenging to study specimens that are low-abundance, low-yield, or short-lived. The recent development of affinity grid techniques holds great promise to tackle these challenging samples by combining the sample purification and freezing on TEM grids steps in cryo-EM grid preparation into a single step, revolutionize the grid preparation of cryo-EM, and extend single particle cryo-EM to a routine structural biology tool to characterize structures …

Contribution Of Probiotics Streptococcus Salivarius Strains K12 And M18 To Oral Health In Humans: A Review, Turner A. Stowik

Honors Scholar Theses

The overgrowth and disequilibrium of pathogenic microorganism species both native and non-native to the oral cavity can manifest into a variety of different oral diseases, pathologies, and afflictions in humans, including dental caries, gingivitis, pharyngitis, halitosis, and oral candidiasis. Two bacterial strains with clinically-significant probiotic applications in curtailing the pathogenic bacterial growth involved in these conditions are Streptococcus salivarius strain K12 and Streptococcus salivarius strain M18. To summarize the most up-to-date in vitro, in vivo, and clinical research findings, administration of these S. salivarius strains typically in the form of probiotic lozenges results in colonization, reduction in inflammatory measures, …

Characterization Of Induced Rnai Silencing Of Vaccinia Virus Essential Genes, Kewa Jiang

Honors Scholar Theses

Vaccinia virus (VACV) is a large double-stranded DNA virus and the prototypical member of the family Poxviridae and is most notable for its use as the vaccine that eradicated smallpox (variola virus). More recently, VACV has been used to develop recombinant vaccines and immunotherapies. However, many of these processes require VACV replication to be tightly controlled. RNA interference (RNAi) is a powerful tool for in vitro silencing of mRNAs that are complementary to 19-21 base pairs (bp) of double-stranded RNA (dsRNA). This project outlines the design and preliminary analysis of two inducible RNAi silencing constructs targeting multiple VACV essential genes …

Sa-4-1bbl As A Modulator Of Innate, Adaptive, And Regulatory Immunity : Implications For Cancer Prevention And Treatment., Hampartsoum Barsoumian

Electronic Theses and Dissertations

SA-4-1BBL is a recombinant costimulatory molecule that is active in its soluble form and has pleiotropic effects on the functions of innate, adaptive, and regulatory immune cells. We have previously shown that SA-4-1BBL makes CD4+ T conventional cells (Tconvs) resistant to suppression by CD4+CD25+Foxp3+ T regulatory cells (Tregs). The mechanistic basis of this observation is the subject of this study. We demonstrate that Tconvs, but not Tregs, are the direct targets of SA-4-1BBL-mediated evasion of Treg suppression without contribution from antigen presenting cells (APCs). SA-4-1BBL engagement with its receptor, 4-1BB, on Tconvs resulted in the production of high levels of …

Effects Of Lactobacillus Rhamnosus Milk Isolate On The Production Of Inflammatory Cytokines In Enterocytes, Beverly C. Ngeny

Electronic Theses and Dissertations

In the gastrointestinal tract, probiotics have been shown to promote host immunity and to regulate immune signaling pathways. This study used Caco-2 cell line to examine the effects of a Lactobacillus rhamnosus isolate from “amabere amaruranu” a Kenyan traditional cultured milk, on the production inflammatory cytokines in enterocytes. Live Lactobacillus rhamnosus (MRS6AN), its cytoplasmic fraction (CF), filtered spent broth (FSB) or heat inactivated FSB (HIB) were used as treatments on differentiated Caco-2 cell monolayer in transwells. Cytokine content in the cell lysates, apical and basolateral supernatants were determined using ELISA. Caco-2 cell lysate treatments showed significantly increased anti-inflammatory TGF-β (ng/ml) …

Comparison Of Anti-Pneumococcal Functions Of Native And Modified Forms Of C-Reactive Protein, Donald Neba Ngwa

Electronic Theses and Dissertations

The anti-pneumococcal function of native C-reactive protein (CRP) involves its binding to phosphocholine molecules present on Streptococcus pneumoniae and subsequent activation of the complement system. However, when pneumococci recruit complement inhibitory protein factor H on their surface, they escape complement attack. Non-native forms of CRP have been shown to bind immobilized factor H. Accordingly, we hypothesized that modified CRP would bind to factor H on pneumococci, masking its complement inhibitory activity, allowing native CRP to exert its anti-pneumococcal function. As reported previously, native CRP protected mice from lethal pneumococcal infection when injected 30 minutes before infection but not when injected …

Effects Of Thermosonication On Microbial Population Reduction And Solubility Index In Skim Milk Powder, Nicola F. Beatty

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thermosonication has been researched as a means to improve shelf life, quality, and functional properties in dairy products. This study explored the effects of thermosonication on the inactivation of Geobacillus stearothermophilus in concentrated skim milk as a function of total solids content, temperature, and time and investigated changes in the solubility of the skim milk. Results showed thermosonication had an increased bactericidal effect on both vegetative cells and spores as compared to heat treatment alone without affecting solubility. A model was developed using response surface analysis showing that log reductions produced by thermosonication can be predicted based on a polynomial …

Effectiveness Of Commercially-Available Cosmetic Cleaners On Cosmetics And Cosmetic Brushes, Vanessa Ortiz

UNLV Theses, Dissertations, Professional Papers, and Capstones

The complex nature of skin contributes to the microbial population present on its surface. While normal skin flora is either beneficial or has no effect on the body, there are instances where pathogenic microorganisms are present and can cause infections. Damaged skin is more susceptible to infections from these microbes. Behavioral characteristics, such as the use of cosmetics, can affect the microbial population present on the skin. Staphylococcus aureus is the organism most commonly isolated from cosmetics, and it can be responsible for conjunctivitis, impetigo, boils, and folliculitis.

There are many ways microbial contamination of cosmetics can occur, such as …

Microbial Contamination Of Ice At Food Establishments In Las Vegas, Nevada, Jerry Wills

UNLV Theses, Dissertations, Professional Papers, and Capstones

When food establishments make ice for consumption, it is important to use water free of pathogens and to employ hygienic practices. Freezing can reduce the number of culturable microorganisms present in water but does not eliminate them completely. Coliform bacteria are used as an indicator of water quality and are used to test for fecal contamination. The U.S. Environmental Protection Agency (EPA) establishes standards for drinking water, and has set a goal for zero total coliforms. Another commonly used tool to measure water quality is the heterotrophic plate count (HPC). The EPA limit for HPC is 500 colony forming units …

Identification Of Host Factors Required For Yersinia Pestis Macrophage Intracellular Survival And Their Impact On Vacuole Maturation, Acidification And Trafficking., Michael Graylin Connor

Electronic Theses and Dissertations

Y. pestis is a facultative intracellular pathogen and the causative agent of plague. This bacterium, while most noted or the Black Death during the European 14^th century, is not a historic pathogen but a re-emerging pandemic with both domestic and global impact. Y. pestis is capable of colonizing the macrophage, and actively subverts phagolysosome maturation to establish a replicative niche known as the Yersinia containing vacuole (YCV). The exploited host factors required to support the YCV are unknown. Here we identified a comprehensive list of host factors required for Y. pestis survival through a genome-wide RNAi high-throughput screen. We …

Characterization Of The Role Of The Burkholderia Pseudomallei Type 3 Secretion System Using In Vivo Imaging., Maria Gabriela Gutierrez

Electronic Theses and Dissertations

Melioidosis is a fatal infectious disease caused by the Tier 1 Select Agent Burkholderia pseudomallei. Hallmarks of melioidosis include pneumonic disease and prominent septicaemic spread. Both forms of disease are contingent upon the bacterium’s intracellular life cycle and particularly on its ability to escape from host cell phagosomes. Upon encountering a host cell, B. pseudomallei is internalized into membrane-bound vacuoles from which the bacterium must rapidly escape to the cytoplasm in order to replicate and promote its survival. In the host cytoplasm, B. pseudomallei is capable of polymerizing actin for intracellular and intercellular motility and spread, lysing the host …

Modulation Of Cell Death Signaling And Cell Proliferation By The Interaction Of Homoserine Lactones And Paraoxonase 2., Aaron Mackallan Neely

Electronic Theses and Dissertations

Pseudomonas aeruginosa produces N-(3-oxododecanoyl)-homoserine lactone (C12) as a quorum-sensing molecule that functions to facilitate bacteria-bacteria communication. C12 has also been reported to affect many aspects of human host cell physiology, including evoking cell death in various types of cells. However, the signaling pathway(s) leading to C12-triggerred cell death remains unclear. To clarify cell death signaling induced by C12, we examined mouse embryonic fibroblasts (MEFs) deficient in one or more caspases. Our data indicate that, unlike most apoptotic inducers, C12 evokes a novel form of apoptosis in cells, probably through the direct induction of mitochondrial membrane permeabilization. Previous studies indicate that …

Insights Into Determinants That Contribute To Colonization, Virulence And Antibiotic Resistance In Enterococci, Maria Camila Montealegre

Dissertations and Theses (Open Access)

Enterococcus faecalis and Enterococcus faecium are increasingly common as causative agents of human infections, many of which are very difficult to treat due to multi-drug resistance. The work presented in the first part of this dissertation elucidates a mechanism for the regulation of pilus expression. I showed that ATT is the initiation codon of ebpA, the first gene of an operon that codes for the endocarditis and biofilm-associated pili (Ebp), a recognized virulence factor in E. faecalis. The presence of this rare start codon downregulates EbpA translation and protein levels, diminishing biofilm and binding abilities of …

The Thioredoxin Trx-1 Regulates The Major Oxidative Stress Response Transcription Factor, Skn-1, In Caenorhabditis Elegans, Katie C. Mccallum

Dissertations and Theses (Open Access)

The ability to respond to hostile environmental conditions is critical for the survival of an organism. Oxidative stress is an adverse state in which reactive oxygen species (ROS) accumulate to a harmful level and, if left unresolved, can lead to cellular dysfunction and organismal disease. Sophisticated detoxification systems, characterized by a battery of enzymatic antioxidants, are utilized to neutralize ROS thereby reducing stress. However, ROS are also purposefully produced by designated cellular enzymes to facilitate the signaling and regulation of critical physiological processes. Therefore, both the production and neutralization of ROS must be tightly controlled. Indeed, the expression of detoxification …

Organization And Regulation Of Proteins Required For Initiation Of Cell Division In Escherichia Coli, Veronica W. Rowlett

Dissertations and Theses (Open Access)

The process of bacterial cell division relies on the assembly of multiple proteins to form the cell division machine, or “divisome.” FtsZ, a bacterial homolog of eukaryotic tubulin, forms a ring-like structure, the “Z ring,” at midcell and serves as a scaffold for divisome assembly and potential force generator during synthesis of the division septum. Both FtsA, a bacterial homolog of eukaryotic actin, and ZipA, a single-pass transmembrane protein, anchor the Z ring to the inner membrane, are required for the localization of other divisome proteins to midcell, and likely influence the assembly state of FtsZ. Positioning of the Z …