Microbiology Commons^™

Studies On The Effects Of Plant Variety And Root Exudate Compounds On The Soil Microbial Community, Márton Szoboszlay

Theses and Dissertations--Plant and Soil Sciences

Plants modify the soil environment through their root system, changing its physical properties and exuding compounds that promote or inhibit the growth of certain microorganisms. Therefore the structure of the soil microbial community is different in the rhizosphere than in the bulk soil. This dissertation introduces three research projects that investigated the effects of specific root exudate compounds on the soil microbial community structure, and plant cultivar specific differences in the rhizosphere microbiota.

The progenitor of maize is Balsas teosinte (Zea mays subsp. parviglumis). In a greenhouse experiment we compared the structure and function of its bacterial and …

Mechanism Of Inactivation By High Voltage Atmospheric Cold Plasma Differs Between Escherichia Coli And Staphylococcus Aureus, Lu Han, Sonal Patil, Daniela Boehm, Vladimir Milosavljević, Patrick J. Cullen, Paula Bourke

Articles

Atmospheric cold plasma (ACP) is a promising non-thermal technology effective against a wide range of pathogenic microorganisms. Reactive oxygen species (ROS) play a crucial inactivation role when air or other oxygen containing gases are used. With strong oxidative stress, cells can be damaged by lipid peroxidation, enzyme inactivation and DNA cleavage. Identifying ROS and understanding their role is important to advance ACP applications to a range of complex microbiological issues. In this study, the inactivation efficacy of in-package, high voltage (80 kV_RMS) ACP (HVACP) and the role of intracellular ROS were investigated. Two mechanisms of inactivation were observed …

Humboldt Journal Of Microbiology: Volume 17, Number 1- May 2015, Press Humboldt

Humboldt Journal of Microbiology

No abstract provided.

Exploring The Pathogenic And Drug Resistance Mechanisms Of Staphylococcus Aureus, Whittney Burda

USF Tampa Graduate Theses and Dissertations

We have previously identified σS, an ECF sigma factor that is important in the virulence and stress response of S. aureus. Transcriptional profiling of sigS revealed that it is differentially regulated in a variety of laboratory and clinical strains of S. aureus, suggesting that there exists a regulatory network that modulates its expression. In order to identify direct regulators of sigS expression, we performed a biotin pull down assay in tandem with mass spectrometry. We identified CymR as a direct regulator and observed that sigS expression is increased in cells lacking cymR. In addition, transposon mutagenesis was performed to identify …

Exploring The Role Of Intracellular Aminopeptidases In Staphylococcus Aureus Pathogenesis, Devon Nicole Marking

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a remarkably pathogenic bacterium that is widely prevalent among the human population. It is the leading agent of skin and soft tissue infections, and is also responsible for causing an array of severe and life threatening diseases. The invasiveness of the pathogen, coupled with increasing antibiotic resistance seen for S. aureus infections, makes this bacterium a prominent public health concern. The extended pathogenicity of S. aureus is largely due to its repertoire of virulence factors, which are typically characterized by being bound to the cell wall, or secreted into the extracellular environment. Previously, our lab identified a …

Mcl1 Enhances The Survival Of Cd8+ Memory T Cells After Viral Infection, Jingang Gui, Zhuting Hu, Ching-Yi Tsai, Tian Ma, Yan Song, Amanda Morales, Li-Hao Huang, Ethan Dmitrovsky, Ruth Craig, Edward Usherwood

Dartmouth Scholarship

Viral infection results in the generation of massive numbers of activated effector CD8+ T cells that recognize viral components. Most of these are short-lived effector T cells (SLECs) that die after clearance of the virus. However, a small proportion of this population survives and forms antigen-specific memory precursor effector cells (MPECs), which ultimately develop into memory cells. These can participate in a recall response upon reexposure to antigen even at protracted times postinfection. Here, antiapoptotic myeloid cell leukemia 1 (MCL1) was found to prolong survival upon T cell stimulation, and mice expressing human MCL1 as a transgene exhibited a skewing …

Atmospheric Cold Plasma As A Tool For Microbiological Control, Dana Ziuzina

Doctoral

Outbreaks of foodborne human illnesses resulting from contaminated raw or minimally processed fruits and vegetables have been widely reported globally. The microbiological challenges associated with fresh produce are diverse and respond differently to minimal processing technologies. Atmospheric cold plasma is a relatively new technology and represents a potential alternative to traditional methods for decontamination of foods. The objective of this work was to determine the influence of extrinsic atmospheric cold plasma (ACP) treatment control parameters and to optimize treatment parameters for decontamination with respect to different forms of key safety challenges pertinent to fresh produce.

The optimisation studies demonstrated that …

Role Of Crebh In Endotoxin Mediated Modulation Of Hepatic Metabolism, Aditya Prakash Dandekar

Wayne State University Dissertations

Bacterial endotoxins can induce a variety of physiological changes in the host. This effect is not only restricted to inflammatory changes but also comprises metabolic changes in the host body. Lipopolysaccharide (LPS), one of the key components of the bacterial cell walls, is capable of triggering host metabolic changes. Hyperlipidemia usually accompanies with high endotoxin levels as well as inflammation. Lipid metabolism disorders are one of the common hallmarks of a patient with sepsis or high levels of endotoxin through diet. Previously, we have identified an endoplasmic reticulum (ER) anchored liver-specific transcription factor CREBH (cAMP-responsive element-binding protein, hepatocyte-specific), which is …

Characterisation And Applications Of Natural Lactic Acid Bacteria With Emphasis On Weissella Cibaria And Associated Exopolysaccharide, Kieran M. Lynch

Theses

The work presented in this thesis characterises natural cereal-derived lactic acid bacteria and examines their potential application in the dairy fermentation area, with special emphasis on the sourdough isolate, Weissella cibaria MGl and its associated glucan homoexopolysaccharide. This strain is notable for its high-level production of dextran, being termed a “hyper-producef’. Genome sequencing and analysis of a number of IV. cibaria strains was performed in the context of available genomic data for other Weissella species, with special focus on the metabolic traits of W. cibaria MGl, and the results represent the first study to explore members of the Weissella genus …

Exploiting Bacteriophages And Associated Peptidoglycan Hydrolases With Potential For Biocontrol In Food Related Applications, Lorraine Endersen

Theses

The work presented in this thesis describes the isolation and characterisation of novel bacteriophages, and the subsequent exploitation of their bactericidal properties against two opportunistic food related pathogens, Mycobacterium avium subsp. paratuberculosis (MAP) and Cronobacter sakazakii.

MAP is a proven animal pathogen known to cause Johne’s disease in cattle but has been implicated as a causative agent of Crohn’s disease in humans. Despite the fact that this association has yet to be proven, significant focus has been directed towards evaluating the consequences of consuming milk contaminated with MAP. Accordingly, six mycobacteriophages were isolated and characterised in terms of temperature and …

The Effect Of Antibiotics On Pseudomonas Aeruginosa Biofilm Production, Courtney Paige Turpin

Online Theses and Dissertations

Antibiotic-resistant bacteria have become an increasing burden worldwide. A highly resistant species is Pseudomonas aeruginosa, a nosocomial pathogen that produces a biofilm that enhances its resistance. This project examined the possibility of using bacteriocin, an internal protective toxin produced by some species of bacteria, as a potential treatment for resistant bacteria. In this study, standard broad spectrum antibiotics were used to treat P. aeruginosa to prevent biofilm formation. The biofilm was then analyzed to determine if the biofilm is inhibited or facilitated by each treatment. Optimal concentrations of antibiotics were determined to be effective at a concentration of 0.07mg/mL for …

Silver Nanoparticles Inhibit The Binding And Replication Of Dengue Virus, Kelley J. Williams

Browse all Theses and Dissertations

Dengue is an emerging hemorrhagic fever virus and widely considered the most important arbovirus in the world. The CDC and the World Health Organization estimates Dengue virus (DENV) infects 50-400 million people annually in the tropical and subtropical regions of the world. More than 500 thousand of these will develop severe infection and approximately 22 thousand will lead to death. Dengue virus (DENV) is a positive-sense RNA virus that exists in 4 antigenic serotypes. An immunological phenomenon called antibody-dependent enhancement (ADE) leaves a DENV victim vulnerable to increased risk of subsequent infections. Secondary infections with DENV are known to increase …

The Impact Of Hsv-1 Infection On Cell Viability, Morphology, And Cd Markers Expression By Unpolarized And Cytokine-Polarized J774a.1 Mouse Macrophages, Sarah Saad Alsharif

Browse all Theses and Dissertations

Macrophages play an important role in the immune system, particularly in neutralizing pathogens via phagocytosis and the production of multiple cytokines and chemokines that control infection after exposure to specific stimuli. Macrophages exhibit two different phenotypes, M1 and M2. This study evaluated the role of Suppressors of cytokine signaling (SOCS)1 and SOCS3 on Herpes Simplex Virus (HSV-1) infection of polarized macrophages, cell viability, cell morphology, and the expression of cell surface CD markers. I hypothesized that J774A.1 murine macrophages cells in the naive state (M0), and M1 and M2 phenotypes would display differences in CD markers CD80,CD163, and CD200R, cell …

Inhibition Of Nectin-1 And Herpes Virus Entry Mediator (Hvem) Using Monoclonal Antibodies Decreases Hsv-1 Entry Into Neuro-2a Cells, Erica Marie Rinehart

Browse all Theses and Dissertations

This study examines the effects of blocking the nectin-1 and Herpes Virus Entry Mediator (HVEM) receptors on Neuro-2a (N2a) cells in order to prevent HSV-1 infection. These two receptors have been identified as a primary and secondary mode of entry for HSV-1. Since there was some debate about the correct serum level to be used in growth media for healthy N2a cells, three concentrations (2%, 5%, 10%) were used to examine relative growth and neurite development, in addition to examining possible differences in infectivity levels in all other experiments. There was a difference in general morphology, with neurite abundance and …

The Use Of Antibody-Coated Latex Beads To Determine Single Positive And Double Positive Mouse Spleen Cells Expressing Cd5 And/Or Cd19 Glycoproteins, Abdulrazzag Abdulaziz Othman

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Flow cytometry is the standard method used to diagnose, stage, and monitor patients' response to the treatment given by counting the numbers of CD5, CD19 and CD5+ CD19+ B lymphocytes. In this study, a comparison was done between numbers of single CD5+, single CD19+ and dual CD5+ CD19+ mouse spleen B lymphocytes using flow cytometry and antibody-latex beads. The bead method involved antibody-coated latex bead and yielded results similar to those of flow cytometry. For cells exhibiting both markers (CD5+ CD19+), the bead method used antibody-coated beads of two different colors yielded similar results to those of flow cytometry results. …

Metagenomics For Bacteriology, Erika Del Castillo, Jacques Izard

Department of Food Science and Technology: Faculty Publications

The study of bacteria, or bacteriology, has gone through transformative waves since its inception in the 1600s. It all started by the visualization of bacteria using light microscopy by Antonie van Leeuwenhoek, when he first described “animalcules.” Direct cellular observation then evolved into utilizing different wavelengths on novel platforms such as electron, fluorescence, and even near-infrared microscopy. Understanding the link between microbes and disease (pathogenicity) began with the ability to isolate and cultivate organisms through aseptic methodologies starting in the 1700s. These techniques became more prevalent in the following centuries with the work of famous scientists such as Louis Pasteur …

Promises And Prospects Of Microbiome Studies, Maria C. Rivera, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Since Anthony van Leeuwenhoek, first microscopic observations of the unseen microbiota and the more recent realization that little of the microbes in the biosphere are known, humans have developed a deep curiosity to fully understand the inner workings of the microbial realm. Our ability to characterize the complexity of microbial communities in their natural habitats has dramatically improved over the past decade thanks to advances in high-throughput methodologies. By eliminating the need to isolate and culture individual species, metagenomics approaches have removed many of the obstacles that hindered research in the ecology of mixed microbial consortia, providing valuable information about …

Evidence For Placental Hpv Infection In Both Hiv Positive And Negative Women, Chrispin Chisanga, Dawn Eggert, Charles D. Mitchell, Charles Wood, Peter C. Angeletti

Nebraska Center for Virology: Faculty Publications

Human papillomaviruses (HPVs) have previously been reported to infect epithelial trophoblast cells of the placenta. To investigate this possibility, 200 placental samples from Zambian women were separated into HIV+ and HIV− groups and tested for HPV by redundant primer PCR, using GP5+/GP6+ and CPI/CPII primer sets. Three HPV genotypes (HPV6, 16 and 90) were detected in placental samples. Whereas, 20 different HPV genotypes were detected in vaginal sampling of the same patients, suggesting that compartment specific sub-populations of HPV may exist. The incidence of HPV16 in placental samples was almost 2-fold greater in HIV+ women compared to HIV− (p = …

Kaposi’S Sarcoma At The University Teaching Hospital, Lusaka, Zambia In The Antiretroviral Therapy Era, Owen Ngalamika, Veenu Minhas, Charles Wood

Nebraska Center for Virology: Faculty Publications

With great interest, we read the recent publication “Kaposi’s sarcoma in HIV-infected patients in South Africa: Multicohort study in the antiretroviral therapy era” by Bohlius et al. We congratulate the authors for their contribution to this field. In this study the authors observed a decrease in incidence of Kaposi’s sarcoma (KS) in patients treated with anti-retroviral therapy (ART) when compared to patients who are not on ART. These results are encouraging because of the ongoing HIV epidemic in sub-Saharan Africa where KS is still one of the most prevalent cancers. Also, it is a relevant topic to study in …

Development Of Novel Chimeric Epitope Based Diagnostic Antigens And Vaccines For Lyme Disease, Lee D. Oliver Jr.

Theses and Dissertations

Lyme disease (LD) is the leading arthropod-borne disease in North America with 300-600,000 cases each year. There are currently no approved human LD vaccines. Outer surface protein C (OspC) has emerged as a leading vaccine candidate and an attractive diagnostic marker due to its antigenicity and expression early in infection. Several chimeric, epitope based OspC derived proteins were generated. The constructs were found to be highly immunogenic in mice and vaccination induced complement-dependent bactericidal antibodies. These results suggest that a broadly protective polyvalent OspC epitope based vaccine can be produced. Currently, LD diagnostic approaches are unreliable and unable to differentiate …