Pathogenic Microbiology Commons^™

Molecular Biology Of A Surface-Exposed Protein Family Of Bartonella Bacilliformis, Hannah Fay

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Bartonella bacilliformis is a gram negative alpha-proteobacterium native to the Andes of South America. Bartonella causes Carrion’s disease, a potentially life threatening disease transmitted by the sand fly. It has a mortality rate of 88% when untreated and 10% when treated. Diagnostics and control measures for the disease are underdeveloped and no vaccine is available. Recent outbreaks indicate that the range of the pathogen is increasing with nearly 1.7 million people in western South America at risk. Little is known about the epidemiology and pathogenesis of B. bacilliformis. Recent research done by UC San Diego found a paralogous gene …

Contribution Of A Class Ii Ribonucleotide Reductase To The Manganese Dependence Of Streptococcus Sanguinis, John L. Smith

Theses and Dissertations

Manganese-deficient Streptococcus sanguinis mutants exhibit a dramatic decrease in virulence for infective endocarditis and in aerobic growth in manganese-limited media. Loss of activity of a manganese-dependent, oxygen-dependent ribonucleotide reductase (RNR) could explain the decrease in virulence. When the genes encoding this RNR are deleted, there is no growth of the mutant in aerobic broth culture or in an animal model. Testing the contribution of the aerobic RNR to the phenotype of a manganese transporter mutant, a heterologous class II RNR from Lactobacillus leichmannii called NrdJ that requires B₁₂ rather than manganese as a cofactor was previously introduced into an …

Amixicile Inhibits Anaerobic Bacteria Within An Oral Microbiome Derived From Patients With Chronic Periodontitis, Kane Ramsey

Theses and Dissertations

Periodontitis is a chronic inflammatory disease caused by pathogenic bacteria residing in a complex biofilm within a susceptible host. Amixicile is a non-toxic, readily bioavailable novel antimicrobial that targets strict anaerobes through inhibition of the activity of Pyruvate Ferredoxin Oxidoreductase (PFOR), a major enzyme mediating oxidative decarboxylation of pyruvate. Our study aimed to evaluate the efficacy of amixicile, when compared to metronidazole, in inhibiting the growth of bacteria present in a microbiome harvested from patients with chronic periodontitis.

Plaque samples were harvested from patients with severe chronic periodontitis and cultured under anaerobic conditions. The microbiomes were grown in the presence …

Deciphering Fungal Dimorphism: Farnesol’S Unanswered Questions, Kenneth Nickerson, Audrey L. Atkin

Kenneth Nickerson Papers

Candida albicans excretes E,E-farnesol as a virulence factor and quorum sensing molecule that prevents the yeast to hyphal conversion. Polke et al. (2016) identified eed1Δ/Δ as the first farnesol hypersensitive mutant of C. albicans. eed1Δ/Δ also excretes 10X more farnesol and while able to form hyphae, it cannot maintain hyphae. This mutant enables new research into unanswered questions, including the existence of potential farnesol receptors and transporters, regulation of farnesol synthesis, and relationships among farnesol, germ tube formation and hyphal maintenance. The eed1 farnesol hypersensitivity can be explained by higher internal concentrations of farnesol or lower thresholds for response. One …

Controlling Brochothrix Thermosphacta As A Spoilage Risk Using In Package Atmospheric Cold Plasma, Apurva Patange, Daniela Boehm, Carmen Bueno-Ferrer, Patrick J. Cullen, Paula Bourke

Articles

Brochothrix thermosphacta is a predominant spoilage microorganism in meat and its control in processing environments is important to maintain meat product quality. Atmospheric cold plasma is of interest for control of pathogenic and spoilage microorganisms in foods. This study ascertained the potential of dielectric barrier discharge atmospheric cold plasma (DBD-ACP) for control of B. thermosphacta in response to key parameters such as treatment time, voltage level, interactions with media composition and post treatment storage conditions. Challenge populations were evaluated as suspensions in PBS, as biofilms in meat model medium and surface attached on raw lamb chops under MAP.

ACP treatment …

Loss Of Outer Membrane Porins In Clonally Related Clinical Isolates Of Klebsiella Pneumoniae Modifies The Bacteria; Resulting In Altered Resistance To Phagocytosis By Macrophages, Debra Nickole Brunson

UNF Graduate Theses and Dissertations

Klebsiella pneumoniae is an opportunistic pathogen responsible for lobar pneumoniae, liver abscess, and septicemia. Clinical isolates are found to be extended spectrum beta lactamase positive with differential expression of the two classical porins, OmpK35 and OmpK36. Porin loss is associated with increased minimum inhibitory concentrations of beta lactam, cephalosporin, and carbapenem antibiotics that target the peptidoglycan. However, little is known about how porin loss affects other aspects of the cell envelope. The focus of this study was to characterize clinical isolates exhibiting differential porin expression and determine if the cumulative changes altered the resistance to phagocytosis by macrophages. The results …

Hub Proteins, Paralogs, And Unknown Proteins In Bacterial Interaction Networks, Neha Sakhawalkar

Theses and Dissertations

Proteins are the functional units of cells. However, a major portion of the proteome does not have a known functional annotation. This dissertation explores protein -protein interactions, involving these uncharacterized or unknown function proteins. Initially, protein – protein interactions were tested and analyzed for paralogous proteins in Escherichia coli. To expand this concept further and to get an overview, protein – protein interactions were analyzed using ‘comparative interactomics’ for four pathogenic bacterial species including Escherichia coli, Yersinia pestis, Vibrio cholerae and Staphylococcus aureus. This approach was used to study unknown function protein pairs as well as to …

Expression Of Matrix Metalloproteinases In Naegleria Fowleri And Their Role In Degradation Of The Extracellular Matrix, Charlton Lam

Theses and Dissertations

Naegleria fowleri is a free-living amoeba found in freshwater lakes and ponds that is the causative agent of Primary Amoebic Meningoencephalitis (PAM). Matrix metalloproteinases (MMPs) have been described in protozoa, such as Plasmodium falciparum, Trypanosoma brucei, and Balamuthia mandrillaris, and have been linked to their increased motility and invasive capability by degrading components of the extracellular matrix (ECM). In addition, MMPs are often upregulated in tumorigenic cells and have been attributed as responsible for the metastasis of certain cancers. In the present study, in vitro experiments indicated that MMPs are linked functionally to the ECM degradation process. …

Comparative Genomic Analysis Of Two Serotype 1/2b Listeria Monocytogenes Isolates From Analogous Environmental Niches Demonstrates The Influence Of Hypervariable Hotspots In Defining Pathogenesis, Aidan Casey, Kieran Jordan, Aidan Coffey, Edward M. Fox, Olivia Mcauliffe

Department of Biological Sciences Publications

The vast majority of clinical human listeriosis cases are caused by serotype 1/2a, 1/2b, 1/2c, and 4b isolates of Listeria monocytogenes. The ability of L. monocytogenes to establish a systemic listeriosis infection within a host organism relies on a combination of genes that are involved in cell recognition, internalization, evasion of host defenses, and in vitro survival and growth. Recently, whole genome sequencing and comparative genomic analysis have proven to be powerful tools for the identification of these virulence-associated genes in L. monocytogenes. In this study, two serotype 1/2b strains of L. monocytogenes with analogous isolation sources, but …

Genetic Determinants Of Salmonella And Campylobacter Required For In Vitro Fitness, Rabindra Kumar Mandal

Graduate Theses and Dissertations

Non-typhoidal Salmonella (NTS) and Campylobacter play a major role in foodborne illness caused by the consumption of food contaminated by pathogens worldwide. A comprehensive understanding of the genetic factors that increase the survival fitness of these foodborne pathogens will effectively help us formulate mitigation strategies without affecting the nutrition ecology. The objective of this study was to identify the genetic determinants of Salmonella and Campylobacter that are required for fitness under various in vitro conditions. For the purpose, we used a high throughput Transposon sequencing (Tn-seq) that utilizes next generation sequencing (NGS) to screen hundreds of thousands of mutants simultaneously. …

A Portable And Automatic Biosensing Instrument For Detection Of Foodborne Pathogenic Bacteria In Food Samples, Zhuo Zhao

Graduate Theses and Dissertations

Foodborne diseases are a growing public health problem. In recent years, many rapid detection methods have been reported, but most of them are still in lab research and not practical for use in the field. In this study, a portable and automatic biosensing instrument was designed and constructed for separation and detection of target pathogens in food samples using nanobead-based magnetic separation and quantum dots (QDs)-labeled fluorescence measurement. The instrument consisted of a laptop with LabVIEW software, a data acquisition card (DAQ), a fluorescent detector, micro-pumps, stepper motors, and 3D printed tube holders. First, a sample in a syringe was …

The Roles Of Biotin In Candida Albicans Physiology, Nur Ras Aini Ahmad Hussin

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

Due to the increased number of immunocompromised patients, infections by Candida albicans have significantly increased in recent years. C. albicans transition from yeast to germ tubes is an essential factor for virulence. In this study we noted that Lee's medium, commonly used to induce filamentation, contained 500-fold more biotin than needed for growth. Thus, we investigated the effects of excess biotin on growth rate and filamentation by C. albicans in different media. At 37 °C, excess biotin (4 µM) enhanced germ tube formation (GTF) ca. 10-fold in both Lee's medium and a defined glucose proline medium, and ca. …

Fluid Dynamic Factors As A Cause And Effect Of Biofilm Formation Of Staphylococcus Aureus Biofilms, Erica Sherman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Staphylococcus aureus bacteria are able to form biofilms and distinctive tower structures that facilitate their ability to tolerate treatment and to spread within the human body. The formation of towers, which break off, get carried downstream and serve to initiate biofilms in other parts of the body are of particular interest here. It is known that flow conditions play a role in the development, dispersion and propagation of biofilms. The influence of flow on tower formation and what factors lead to tower formation is not at all understood The hypothesis being examined is that tower structures form within a specific …

Nutrition And Helicobacter Pylori: Host Diet And Nutritional Immunity Influence Bacterial Virulence And Disease Outcome, Kathryn P. Haley, Jennifer A. Gaddy

Peer Reviewed Articles

Helicobacter pylori colonizes the stomachs of greater than 50% of the world’s human population making it arguably one of the most successful bacterial pathogens. Chronic H. pylori colonization results in gastritis in nearly all patients; however in a subset of people, persistent infection with H. pylori is associated with an increased risk for more severe disease outcomes including B-cell lymphoma of mucosal-associated lymphoid tissue (MALT lymphoma) and invasive adenocarcinoma. Research aimed at elucidating determinants that mediate disease progression has revealed genetic differences in both humans and H. pylori which increase the risk for developing gastric cancer. Furthermore, host diet and …

Calling In Sick: Impacts Of Fever On Intra-Urban Human Mobility, T. Alex Perkins, Valerie A. Paz-Soldan, Steven T. Stoddard, Amy C. Morrison, Brett M. Forshey, Kanya C. Long, Eric S. Halsey, Tadeusz J. Kochel, John P. Elder, Uriel Kitron, Thomas W. Scott, Gonzalo M. Vazquez-Prokopec

Faculty Publications

© 2016 The Author(s) Published by the Royal Society. All rights reserved. Pathogens inflict a wide variety of disease manifestations on their hosts, yet the impacts of disease on the behaviour of infected hosts are rarely studied empirically and are seldom accounted for in mathematical models of transmission dynamics. We explored the potential impacts of one of the most common disease manifestations, fever, on a key determinant of pathogen transmission, host mobility, in residents of the Amazonian city of Iquitos, Peru. We did so by comparing two groups of febrile individuals (dengue-positive and dengue-negative) with an afebrile control group. A …

Comparative Genomics, Transcriptomics, And Physiology Distinguish Symbiotic From Free-Living Chlorella Strains, Cristian F. Quispe, Olivia Sonderman, Maya Khasin, Wayne R. Riekhof, James L. Van Etten, Kenneth Nickerson

Kenneth Nickerson Papers

Most animal–microbe symbiotic interactions must be advantageous to the host and provide nutritional benefits to the endosymbiont. When the host provides nutrients, it can gain the capacity to control the interaction, promote self-growth, and increase its fitness. Chlorella-like green algae engage in symbiotic relationships with certain protozoans, a partnership that significantly impacts the physiology of both organisms. Consequently, it is often challenging to grow axenic Chlorella cultures after isolation from the host because they are nutrient fastidious and often susceptible to virus infection. We hypothesize that the establishment of a symbiotic relationship resulted in natural selection for nutritional and metabolic …

The Effects Of Quorum Sensing And Temperature On The Soluble Proteome Of Vibrio Salmonicida, Christopher L. Massey

Master's Theses

Vibrio salmonicida causes cold-water vibriosis in salmon populations around the world and causes financial damage to fisheries designed to farm these salmon. Very little is known about the physiology of how V. salmonicida causes disease and measures to contain vibriosis are restricted to either vaccinating individual fish against disease or administering antibiotics when an outbreak is detected. These procedures are costly and increase the risk for selection of antibiotic-resistant V. salmonicida strains. A recent reoccurrence of outbreaks in Norwegian fisheries provided incentive to better understand the virulence mechanisms of V. salmonicida. In this thesis, a proteomic approach was used to …

Needle In The Haystack: Combining Intravital Imaging And Mathematical Modeling To Understand How Vaccine-Induced T Cells Find Malaria-Infected Cells In Murine Livers, Vitaly V. Ganusov, Ian Cockburn, Reka Kelemen

Biology and Medicine Through Mathematics Conference

No abstract provided.

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 …