Pathogenic Microbiology Commons^™

Application Of Supervised Machine Learning Algorithms For Rapid Identification Of Mrsa Pfge Strain Types, Michael L. Bernauer

Biomedical Informatics

Introduction: Pulsed-field gel electrophoresis (PFGE) is a molecular typing method used in epidemiologic surveillance of MRSA. PFGE relies on electrophoretic migration of restricted DNA fragments, resulting in characteristic fingerprints which can be used to classify organisms. Current methods of analysis, such as Gel Compar II and BioNumerics rely on unsupervised hierarchical clustering algorithms to group organisms based on pairwise similarity. These methods are labor intensive, often requiring a significant amount of user intervention and oversight. This study presents an automated approach to PFGE typing to reduce the amount of user involvement and time required for analysis.

Methods: A total of …

Comparative Genomics Of Microbial Chemoreceptor Sequence, Structure, And Function, Aaron Daniel Fleetwood

Doctoral Dissertations

Microbial chemotaxis receptors (chemoreceptors) are complex proteins that sense the external environment and signal for flagella-mediated motility, serving as the GPS of the cell. In order to sense a myriad of physicochemical signals and adapt to diverse environmental niches, sensory regions of chemoreceptors are frenetically duplicated, mutated, or lost. Conversely, the chemoreceptor signaling region is a highly conserved protein domain. Extreme conservation of this domain is necessary because it determines very specific helical secondary, tertiary, and quaternary structures of the protein while simultaneously choreographing a network of interactions with the adaptor protein CheW and the histidine kinase CheA. This dichotomous …

Methane Production By A Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water, Sean Richard Thomson

Master's Theses

Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated several types of media for digestion of dilute wastewaters, but cost and media fouling have setback commercial development. A major operational cost has been effluent recirculation pumping.

In the present effort, a novel approach to anaerobic digestion of flush dairy water was developed at pilot-scale: broken walnut shells were used as a low-cost packed-bed medium and effluent recirculation was replaced …

Modulation Of Host Polyubiquitination By The Ankb F-Box Protein Of Legionella Pneumophila., William M. Bruckert

Electronic Theses and Dissertations

Legionella pneumophila is a facultative intracellular pathogen that infects a wide array of protozoan hosts and human alveolar macrophages. L. pneumophila is dependent on a functional Dot/Icm type IVB secretion system that translocates bacterial effector proteins into the host cell cytosol. L. pneumophila genomes encode more than 250 effector proteins, many of which inhibit host cellular processes to form a favorable niche termed the Legionella-containing vacuole (LCV). The eukaryotic-like Dot/Icm translocated effector AnkB contains two eukaryotic-like ankyrin protein-protein interacting domains, one eukaryotic-like F- box domain and an eukaryotic C-terminal CaaX motif. Immediately following attachment of extracellular bacteria, AnkB is translocated …

The Role Of Superantigens During Staphylococcus Aureus Nasal Colonization And Infection, Stacey Xu

Electronic Thesis and Dissertation Repository

Superantigens (SAgs) are potent toxins produced by bacteria such as Staphylococcus aureus that function to overactivate T cells resulting in massive cytokine production and immune activation. Despite decades of research on the structure and function of these proteins, as well as their role in severe diseases such as toxic shock syndrome, the question as to why strains of S. aureus produce SAgs and the role that they play in the life cycle of these bacteria remains unanswered. The contribution of SAgs towards pathogenicity and bacterial survival in vivo were assessed using isogenic SAg deletion knockouts in conjunction with SAg-sensitive humanized …

The Potential Of Quinoline Derivatives For The Treatment Of Toxoplasma Gondii Infection., Sirinart Ananvoranich

Chemistry and Biochemistry Publications

Here we reported our investigation, as part of our drug repositioning effort, on anti-Toxoplasma properties of newly synthesized quinoline compounds. A collection of 4-aminoquinoline and 4-piperazinylquinoline analogs have recently been synthesized for use in cancer chemotherapy. Some analogs were able to outperform chloroquine, a quinoline derivative drug which is commonly used in the treatment of malaria and other parasitic infections. Herein 58 compounds containing one or two quinoline rings were examined for their effectiveness as potential anti-Toxoplasma compounds. Of these 58 compounds, 32 were efficient at inhibiting Toxoplasma growth (IC50μM). Five compounds with single and simple quinoline rings exhibited similar …

Diversity Of Bacteria Carried By Pinewood Nematode In Usa And Phylogenetic Comparison With Isolates From Other Countries, Diogo Neves Proença, Luís Fonseca, Thomas Powers, Isabel M.O. Abrantes, Paula V. Morais

Department of Plant Pathology: Faculty Publications

Pine wilt disease (PWD) is native to North America and has spread to Asia and Europe. Lately, mutualistic relationship has been suggested between the pinewood nematode (PWN), Bursaphelenchus xylophilus the causal nematode agent of PWD, and bacteria. In countries where PWN occurs, nematodes from diseased trees were reported to carry bacteria from several genera. However no data exists for the United States. The objective of this study was to evaluate the diversity of the bacterial community carried by B. xylophilus, isolated from different Pinus spp. with PWD in Nebraska, United States. The bacteria carried by PWN belonged to Gammaproteobacteria …

Construction And Characterization Of Non-Toxic Bacterial Enterotoxins As Vaccine Adjuvants, Lavanya Vempati

Boise State University Theses and Dissertations

The development of adjuvants that can promote the delivery of purified subunit vaccines by mucosal routes, such as the nose or the mouth, is recognized as a top priority for vaccine research. The bacterial enterotoxins; cholera toxin (CT) and E.coli heat-labile toxin (LTI), have long been recognized as powerful adjuvants with the ability to stimulate specific immune responses to co-administered antigens when delivered to mucosal surfaces. Shiga toxin 1 (ST1) and pertussis toxin (PT) are structurally homologous bacterial toxins secreted by Escherichia coli 0157:H7 and Bordetella pertussis respectively. ST1 and PT also have reported adjuvant activity but it is less …

Potential Roles Of Peroxidases In Caenorhabditis Elegans Innate Immunity, George R. Tiller, George R. Tiller

Dissertations & Theses (Open Access)

The production of ROS (reactive oxygen species) in response to pathogen detection is a rapid, nonspecific response that is evolutionarily conserved from nematodes to humans. ROS serve as direct and indirect effectors of innate and adaptive immunity. In Caenorhabditis elegans, a ROS burst is observed during infection and is mediated by the dual oxidase BLI-3, which produces H₂O₂. RNAi (RNA interference) to reduce the amount of BLI-3 results in a significant increase in susceptibility to pathogens, suggesting BLI-3 has a role in the immune response. However, H₂O₂ by itself is not a …

Development Of Chimeric Type Iv Secretion Systems For Transfer Of Heterologous Substrates Across The Gram-Negative Cell Envelope, Trista M. Berry

Dissertations & Theses (Open Access)

Many bacteria use Type IV Secretion Systems (T4SSs) to aid in pathogenesis by translocating virulence factors across the cell envelope and into eukaryotic cells. These systems are structurally and functionally diverse, but are often compared to the archetypal VirB/VirD4 T4SS of Agrobacterium tumefaciens. This system is composed of the VirD4 type IV coupling protein (T4CP) and 11 VirB subunits (VirB1-11) that assemble as the secretion channel and an extracellular pilus. The T4CP is an inner membrane ATPase that interacts with T4SS substrates and the secretion channel, and is thought to link substrates with the secretion channel and possibly energize …

Impedance Biosensors For The Rapid Detection Of Viral And Bacterial Pathogens Using Avian Influenza Virus Subtypes H5n1 And H7n2 And Escherichia Coli O157:H7 As Model Targets, Jacob David Lum

Graduate Theses and Dissertations

This research investigated impedance biosensors for the rapid detection of viral and bacterial pathogens using avian influenza virus (AIV) subtypes H5N1 and H7N2 and Escherichia coli O157:H7 as the model targets, which were chosen due to their impact on the agricultural and food industries. For the detection of AIV H7N2, a single stranded DNA aptamer was selected using systematic evolution of ligands by exponential enrichment (SELEX). The selected aptamer and a previously selected aptamer against AIV H5N1 were used in a microfluidics chip with an embedded interdigitated array microelectrode to fabricate an impedance biosensor for specific detection of AIV H7N2 …

Identification Of Novel Small Rnas And Characterization Of The 6s Rna Of Coxiella Burnetii, Indu Warrier, Linda D. Hicks, James M. Battisti, Rahul Raghavan, Michael F. Minnick

Biological Sciences Faculty Publications

Coxiella burnetii, an obligate intracellular bacterial pathogen that causes Q fever, undergoes a biphasic developmental cycle that alternates between a metabolically-active large cell variant (LCV) and a dormant small cell variant (SCV). As such, the bacterium undoubtedly employs complex modes of regulating its lifecycle, metabolism and pathogenesis. Small RNAs (sRNAs) have been shown to play important regulatory roles in controlling metabolism and virulence in several pathogenic bacteria. We hypothesize that sRNAs are involved in regulating growth and development of C. burnetii and its infection of host cells. To address the hypothesis and identify potential sRNAs, we subjected total RNA …

Investigating The Viability Of Two Stenotrophomonas Maltophilia Isolates After Air-Drying, Samantha Lane, Joanna Brooke

DePaul Discoveries

Abstract

Stenotrophomonas maltophilia is a water-borne infectious bacterium that is found in both clinical (hospitals) and non-clinical environments. This human pathogen is commonly recovered from respiratory tract infections. A recent study at a hospital in Taiwan suggested that dry patient charts can serve as a vehicle of transmission of this bacterium⁷. As S. maltophilia is not commonly isolated from dry surfaces, this current study tested the hypothesis that this pathogen can remain viable for some time on a dry surface. This study was designed to determine how long S. maltophilia could remain viable after air-drying by observing …

Sub-Inhibitory Antibiotics Enhance Virulence, Persistence, And Pathogenesis Of Uropathogens, Lee W. Goneau

Electronic Thesis and Dissertation Repository

In addition to their bactericidal effects, antibiotics are potent signal mediators at sub-inhibitory levels in the environment. The ability to modulate community structure in this niche raises concerns over their capacity to influence pathogenesis in patients during antibiotic therapy. This concept forms the basis of this thesis, and is explored using models of prophylactic therapy for recurrent urinary tract infection (UTI) management.

Sub-inhibitory ciprofloxacin, ampicillin, and gentamicin were found to augment virulence in vitro, increasing adherence and urothelial cell invasion in uropathogenic Escherichia coli (UPEC) and Staphylococcus saprophyticus. In addition, biofilm formation was increased, and swarming motility decreased. …

Characterization Of Corynebacterium Pseudotuberculosis Biovar Equi Isolates Obtained From Cal Poly Horses And Review Of Application Of Transposons To Better Prevent Pigeon Fever In Horses, Irene Hasen

Animal Science

No abstract provided.

Chlorovirus Skp1 And Core Ankyrin-Repeat Protein Interplay And Mimicry Of Cellular Ubiquitin Ligase Machinery, Eric Andrew Noel

School of Biological Sciences: Dissertations, Theses, and Student Research

The ubiquitin-proteasome system is a common target of several unrelated viruses that have evolved convergent strategies to redirect host ubiquitin machinery to serve their own needs. Members of the genus Chlorovirus, a group of large dsDNA viruses that infect certain freshwater chlorella-like green algae, encode a conserved Skp1 homolog and ankyrin-repeat (ANK) proteins, some of which contain C-terminal domains characteristic of cellular F-boxes or related viral PRANC domains. These observations suggested that this unique combination of chlorovirus proteins either interact with or imitate the key components of the SCF (Skp1-Cul1-F-box) ubiquitin ligases. Using mass spectrometry, we identified two functional …

Use Of Cholera Toxin B As A Vaccine Adjuvant Activates Antigen Presenting Cells And Stimulates Production Of Pro-Inflammatory Cytokines, Heather C. Romlein

Seton Hall University Dissertations and Theses (ETDs)

Francisella tularensis is an intracellular pathogen that has been classified as a category “A” bioterrorism agent by the Centers For Disease Control. To date, there is no approved vaccine to provide protection against this pathogen. Previous in vivo studies with mice have shown that a mucosally targeted vaccine preparation of inactivated F. tularensis (iFt) adjuvanted with Cholera toxin “B” (CTB), successfully granted full protection against a less virulent strain (FT LVS) of the bacterium and provided partial protection against a more virulent strain (SchuS4). However, the mechanisms of this protection are not fully understood. In this …

Regulation Of The Candida Albicans Arginine Biosynthetic Pathway, Claudia Jimenez Lopez

Dissertations & Theses (Open Access)

Candida albicans is the most importan thuman-associatedfungus.It is a commensal microorganism but also an opportunistic pathogen able to cause superficial infections aswellaslife-threateninginfectionswhich are associated with a highmortalityrateof 50%. The interactions between C. albicans and the cells of the mammalian innate immune system, which confer the most important protecting mechanisms against disseminated infections, are very dynamic and determine the success of C. albicans as a pathogen. Transcriptional profiling has shown that phagocytosis of C. albicans by macrophages results primarily in the activation of alternative carbon metabolism pathways suggesting that the pathogen is exposed to a glucose poor environment. Changes in …

Investigating Antibiotic Resistance Levels Of Salmonella Internalized In Lettuce Leaves, Jason B. Thomas

McNair Scholars Research Journal

Contamination of food crops by the human pathogen Salmonella is a food safety threat worldwide. Though using treated wastewater for irrigation is a sustainable practice, it may introduce trace levels of Salmonella that may contaminate food crops. Salmonella could develop resistance to antibiotics present in wastewater. The overall goal of the project is to increase the understanding of the public health risk associated with the use of treated wastewater to irrigate food crops. The objective of this particular study is to determine the antibiotic resistance level of Salmonella internalized in lettuce leaves. In this experiment, thirty-six plants of the lettuce …

Study Of The Function Of The Mold Specific Gene Ms95 In Dna Repair In The Pathogenic, Dimorphic Fungus Histoplasma Capsulatum, Erin M. Smith

Honors Theses

Histoplasma capsulatum (Hc) is a dimorphic fungus that is the etiologic agent of the respiratory infection Histoplasmosis that is mediated by a shift from the mold phase to the pathogenic yeast phase. Genes have been identified that are specific to the mold or yeast phase in order to study the molecular biology of this shift. MS95 was identified in a subtractive cDNA library that was enriched for mold-specific genes, and has been found to be homologous to the DNA damage-responsive gene DDR48, which functions in DNA repair in Saccharomyces cerevisiae. In order to elucidate the function of MS95, a …