Microbiology Commons^™

Isolation And Enumeration Of Vibrio Vulnificus And Vibrio Parahaemolyticus From Coastal Virginia, Zackary A. Zayakosky

Senior Honors Projects, 2010-2019

Vibrio vulnificus and V. parahaemolyticus are gram-negative, halophilic bacteria that are found throughout estuarial waters during the summer months, and are commonly associated with human infection. Gastroenteritis and other related symptoms can occur following infection from either organism, which most often occurs as a result of consumption of raw oysters or other seafood. V. vulnificus is particularly virulent, and can also produce wound infections that lead to severe septicemia and death. Due to the increasing rates of infection for these two organisms, recent research efforts have focused on potential environmental conditions and reservoirs that would be indicative of increased Vibrio …

Spatiotemporal Control Of Staphylococcus Aureus Biofilm Development, Derek E. Moormeier

Theses & Dissertations

Chronic biofilm-related infections caused by the human pathogen Staphylococcus aureus often lead to significant increases in morbidity and mortality in both hospital- and community-associated settings. Typically, S. aureus biofilm development occurs in three stages: 1) attachment, 2) tower maturation, and 3) dispersal. Here, utilizing BioFlux1000 time-lapse microscopy we have expanded upon these fundamental stages of biofilm development and also unveiled and characterized two additional stages (multiplication and exodus).

The attachment and multiplication stages were shown to be protease sensitive but independent of most cell surface-associated proteins. Following multiplication, an exodus of the biofilm population that followed the transition of the …

Regulation Of Cid-Mediated Cell Death In Staphylococcus Aureus, Ian H. Windham

Theses & Dissertations

The death and lysis of a subpopulation of cells in Staphylococcus aureus biofilms is thought to benefit the surviving population by releasing extracellular DNA, a critical component of the biofilm extracellular matrix. Although the means by which S. aureus controls cell death and lysis is not completely understood, studies implicate the role of the cidABC, alsSD and lrgAB operons in this process. This dissertation has focused on the regulation of cidABC and alsSD expression, which is mediated, primarily, by the LysR-Type Transcriptional Regulator (LTTR) known as CidR. To better define the role of CidR in regulating cidABC and alsSD transcription …

Role Of Stemloop D In Terminally Deleted Coxsackievirus B3 Replication, Lee K. Jaramillo

Theses & Dissertations

Coxsackievirus B3 (CVB3) is an enterovirus with no known form of latency. However, assays designed to detect enteroviral RNA have shown that CVB3 RNA can persist for weeks beyond the acute infection both naturally and experimentally. Our previous work with coxsackievirus revealed an inhibited version of enteroviral replication where the progeny virus, termed terminally deleted (TD) virus, was missing a maximum of 49 nucleotides from the beginning of the 5’ non-translated region (NTR). The largest terminally deleted virus, TD50, effaced stem a, stemloop b, and stemloop c from the secondary structure, the cloverleaf. We hypothesized that further deletion beyond those …

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 …

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 …

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. …

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 …

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, …