Microbiology Commons^™

A Messenger Molecule Governs Interdependency In An Evolved Pseudomonas Aeruginosa Biofilm Community, Thomas Macelliott Johnson

Honors Theses and Capstones

Biofilm populations are known to harbor great diversity, but the importance of this diversity is not fully understood. A likely contributor to this variation is the second messenger molecule cyclic-di-GMP: low levels associate with a planktonic lifestyle while high levels favor biofilm formation. In ongoing studies of an evolving biofilm population of Pseudomonas aeruginosa (PA), we observed extensive ecological diversification that may relate to this lifestyle switch. In PA, the gene bifA encodes a phosphodiesterase that is known to degrade cyclic-di-GMP and reduce biofilm. This gene was cloned onto a plasmid under control of an inducible promoter and the plasmid …

Humboldt Journal Of Microbiology: Volume 13, Number 1- May 2011, Press Humboldt

Humboldt Journal of Microbiology

No abstract provided.

Microbial Ecology And Functional Genomics Of Deep-Water Coral-Associated Microbes, Julia Parker Galkiewicz

USF Tampa Graduate Theses and Dissertations

Lophelia pertusa is a cosmopolitan cold-water coral, often found in aphotic waters (>200m). Aggregations of L. pertusa (reefs) provide important habitat to many invertebrate and fish species and act as biodiversity hotspots in the deep sea. The health and diversity of these reefs is of vital importance to deep-sea ecosystems, and the microbial consortia associated with L. pertusa form the most basic ecological level. Deciphering the diversity and function of these microbes provides insight into the roles they play in maintaining reef health. This dissertation takes microbiological techniques that are used in shallow-water coral microbial research and applies them …

The Role Of Hiv-1 Proteins In Alzheimer's Disease Pathology, Brian Nelson Giunta

USF Tampa Graduate Theses and Dissertations

Prevalence of HIV-associated cognitive impairment is rising, the worst form of which is HIV-associated dementia (HAD). The disease is fuiled by a chronic innate type pro-inflammatory response in the brain which is highly dependent upon the activation of microglia. We first created an in vitro model of HAD composed of cultured microglial cells synergistically activated by the addition of IFN-gamma and the HIV-1 coat glycoprotein, gp120. This activation, as measured by TNF-alpha and NO release, is synergistically attenuated through the alpha7nAChR and p44/42 MAPK system by pretreatment with nicotine, and the cholinesterase inhibitor, galantamine. As these medications have been FDA …

Synthesis And Antimicrobial Activities Of S,S'-Heterosubstituted Disulfides, Praveen Ramaraju

USF Tampa Graduate Theses and Dissertations

Antibiotic resistance is a particularly critical health concern and has increased dramatically over the past two decades. For over a decade the Turos laboratory has been designing small molecules to target pathogenic microbes such as Staphylococcus aureus and the resistant variants like methicillin-resistant Staphylococcus aureus (MRSA). Previously, N-thiolated Β-lactams, N-thiolated 2-oxazolidinones and aromatic disulfides that were synthesized in Dr. Turos' lab have shown strong activity against these bacteria. The present work describes the synthesis and antimicrobial activities of a related structural class called S,S'-heterosubstituted disulfides. For ages, sulfur (elemental) has been used as an antibacterial for controlling infestation and bacterial …

Characterization Of Aminopeptidase Pepz In Staphylococcus Aureus Virulence, Tiffany Marie Robison

USF Tampa Graduate Theses and Dissertations

Staphylococcus aureus is a remarkably successful pathogen, accounting for an estimated 95,000 invasive infections annually in the U.S. alone. The burden of MRSA infections on public healthcare continues to rise, particularly with the continued spread of antibiotic resistant strains and the hyper-virulent CA-MRSA strains. The pathogenic nature of S. aureus can be attributed to the cache of virulence factors encoded within the genome of this organism. Typically, these are secreted toxins which directly interact with the host during infection, and facilitate pathogenesis. A previous screen in our laboratory investigating proteases in S. aureus identified a mutant in aminopeptidase Z as …

Sex And The Seas: Gene Transfer Agents, Elizabeth Young

USF Tampa Graduate Theses and Dissertations

Gene Transfer Agents (GTAs) are phage-like pthesiss that are produced by many alpha proteobacteria in late stationary growth phase and are capable of transferring chromosomal genes (termed "constitutive transduction"). Examination of alpha proteobacterial genomic sequences indicated widespread occurrence of GTA-like elements. The goal of this study was to investigate gene transfer potential of GTAs of marine alpha proteobacteria in culture as well as in natural marine environments. Another goal was to determine the potential of bacterial symbionts from zooxanthellae and coral to genetically transfer beneficial properties between symbionts. Ruegeria mobilis (ID 45A6) was isolated from cultures of the coral endosymbiotic …

Assessing The Relationship Of Monocytes With Primary And Secondary Dengue Infection Among Hospitalized Dengue Patients In Malaysia, 2010: A Cross-Sectional Study, Benjamin Glenn Klekamp

USF Tampa Graduate Theses and Dissertations

Dengue, a group of four similar viruses transmitted through the bite of a mosquito, is estimated to infect upwards of 100 million annually in over 100 nations throughout the global equatorial belt. Distribution of global dengue is highly skewed as Southeast Asian and Western Pacific regions endure 75% of the global dengue burden. Similar to other regional countries, Malaysia has been rapidly urbanizing, which has supported a hyperendemic dengue state.

The biological pathway by which dengue infection causes a wide range of clinical manifestations, spanning asymptomatic to life-threatening severe complications, is not comprehensively understood. Historically, severe dengue complications have primarily …

Investigation Of The Optimal Dissolved Co2 Concentration And Ph Combination For The Growth Of Nitrifying Bacteria, Raymond Anthony Morris

USF Tampa Graduate Theses and Dissertations

Ammonium (NH₄⁺) is a biological nutrient that is transformed in a wastewater treatment plant (WWTP) in a process called activated sludge. This is accomplished in an aerobic environment using microorganisms and inorganic carbon that convert the ammonium to nitrate (NO₃^-). This process is termed nitrification. Removal of ammonium is necessary due to its oxygen demand and toxicity to the environment.

Nitrification is considered a slow process due to the slow growth rate of the nitrifying bacteria. Ammonia oxidizing bacteria (AOB) first covert the ammonium (NH₄⁺) to nitrite (NO₂^-) …

Microbial Landscapes Of Corals And Ctenophores, Camille Arian Daniels

USF Tampa Graduate Theses and Dissertations

As technology and engineering allow mankind to survey nature at finer scales, the importance of bacteria has been elucidated in their metabolic diversity, ability to transfer genetic information, involvement in biogeochemical cycling, and sheer abundance. With an individual domain of life unto themselves, this diverse group of microorganisms plays an integral role in facilitating life on land and in the oceans, and is second only to viruses in abundance on Earth. They carve niches in a wide range of environments, including those inhospitable to other life forms, and reside in concert or to the detriment of other microbes and/or hosts …

Development Of A Non-Invasive Electrode For Intradermal Electrically Mediated Dna Vaccination, Amy Lynn Donate

USF Tampa Graduate Theses and Dissertations

Current progress in the development of vaccines has decreased the incidence of fatal and non-fatal infections and increased longevity. However, new technologies need to be developed to combat an emerging generation of infectious diseases. DNA vaccination has been demonstrated to have great potential for use against a wide variety of diseases. Alone, this vaccine technology does not generate a significant immune response for vaccination, but combined with delivery by electroporation (EP), can enhance plasmid expression and immunity against the expressed antigen. Most EP systems, while effective, can be invasive and painful making them less desirable for use in vaccination. Our …

Pleiotropic Regulatory Function Of The Lysr Family Transcriptional Regulator Cpsy During Streptococcus Iniae Systemic Infection, Jonathan Paul Allen

Wayne State University Dissertations

The ability of a pathogen to metabolically adapt to the local environment for optimal expression of virulence determinants is a continued area of research. Orthologs of the Streptococcus iniae LysR family regulator CpsY have been shown to regulate methionine biosynthesis and uptake pathways, but appear to influence expression of several virulence genes as well. A S. iniae mutant with an in-frame deletion of cpsY is highly attenuated in a zebrafish infection model. The cpsY deletion mutant displays a methionine-independent growth defect in serum, which differs from the methionine-dependent defect observed for orthologous mutants of S. mutans and S. agalactiae. …

Characterisation Of Bacterial Extracellular Polysaccharides (Eps) And Other Complex Carbohydrates With Prebiotic Potential, Padraigin Murphy

Theses

Prebiotics are selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microbiota that confers benefits upon host well-being and health’ It is not the prebiotic by itself but rather the changes induced in microflora composition that is responsible for its effects. Several sources of prebiotic were used in this study, namely extracellular polysaccharides (EPS) originating from Lactic Acid Bacteria (LAB), barley, oat. Laminaria digitata. Laminaria hyperborea and Saccharomyces cerevisiae. EPS-producing LAB were isolated from a wide variety of environmental and gastrointestinal niches. The strains were typed and classified according to their EPS-producing ability …

Enhanced Surveillance And Characterisation Of Three Significant Gram-Positive Pathogens, Annmarie Mollaghan

Theses

Clinical microbiology has been revolutionised in recent years by the introduction of molecular biology. Traditionally, the gold standard for diagnosis in the clinical microbiology laboratory has been culture, which in some cases, is gradually being replaced by molecular detection methods, particularly where the pathogen is difficult to grow or to identify, or when the significance of an organism is dependent on the detection of specific markers of pathogenicity, such as toxins. Many fastidious bacteria which are difficult to culture and present public health implications, i.e. Mycobacterium tuberculosis. Chlamydia trachomatis and Neisseria gonorrhoea, can now be detected using commercial molecular assays …

Hsv-1 Infection In Keratinocyte Cell Lines Treated With Mitotic Inhibitors, Asma A. Abbas

Browse all Theses and Dissertations

The hypothesis for this research was: Herpes simplex virus type 1 (HSV-1) infection of murine keratinocyte cell lines (HEL-30 and PAM-212) treated with mitotic inhibitors leads to silencing of virus replication. At 0.1 (Multiplicity of infection) MOI, PAM-212 keratinocytes showed some cell lysis and viral plaques were seen in HEL-30 keratinocyte cultures. PAM-212 keratinocytes, infected at 0.01 MOI, were more susceptible to the lytic effect of HSV-1 than were HEL-30 cells. In this study, 5-fluoro-2'-deoxyuridine (FUDR) treatment of both keratinocyte cell lines permitted an increase survival of HSV-1- infected keratinocytes especially for PAM-212 cell line which was further examined for …

Distribution Of Cellular Interferon Beta (Ifn-Β) In Murine Fibroblast Cell Lines Upon Infection Of Hsv-1, Rachael E. Curtis

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The hypothesis for this study was: IFN-β expression differs between murine fibroblasts (A2R1 and L929) of different mouse strains upon infection of HSV-1. Fluorescent microscopy was used to examine localization of IFN-β in the different murine fibroblast and keratinocyte cell lines after 6 hours of infection with herpes simplex virus type-1 (HSV-1). Because keratinocytes cell lines HEL-30 and PAM-212 grew in clusters, staining patterns in individual cells could not be determined. A notable difference in localization of IFN-β immune staining was seen between the two cell lines when infected with HSV-1. The A2R1 cell line showed perinuclear (PN) localization, while …

Targeted Knockdown Of Amp-Activated Protein Kinase Alpha 1 And Alpha 2 Catalytic Subunits, Larissa J. Tangeman

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AMP-activated protein kinase (AMPK) regulates cellular metabolism and promotes ATP production when energy is depleted. Evidence suggests that AMPK may be involved in oxygen sensing by carotid body cells, which are responsible for regulating the breathing rate to maintain proper blood oxygen levels. There are two isoforms of the catalytic alpha subunit, AMPKalpha1 and AMPKalpha2, which could be involved in oxygen sensing. Here, the production of a short hairpin RNA (shRNA) targeting both catalytic isoforms of AMPK in human, mouse, and rat is described. The shRNA causes significant knockdown of both isoforms of AMPK alpha in mouse and human cells …

Strategies For Long-Term Renal Allograft Survival In Iga Nephropathy Patients, Erin E. Lintz

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IgA nephropathy is one of the most common kidney diseases worldwide. Most IgA nephropathy patients will undergo a kidney transplant as a treatment. Treatment currently includes the use of immunosuppressants which are necessary to prevent graft rejection but present harmful side-effects when taken long-term. This review focuses on strategies which have the ability to promote tolerance of both donor and recipient cells within a transplant recipient. Such strategies allow development of mixed chimerism and thereby alleviate the need for long-term immunosuppressant usage in allograft recipients. These strategies could be applied to IgA nephropathy patients to allow kidney allograft acceptance without …

Amino Acid Substitutions Created In Reverse Transcriptase And Their Influence On Hiv-1 Mutation Frequencies, Amani Saud Alhejely

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As research has shown, a high mutation rate occurs during the reverse transcription RT process because HIV reverse transcriptase fails to correct erroneously incorporated nucleotides during the reverse transcription process. Based on various research articles, a series of amino acid substitutions created in RT were collected to find out their influence on virus mutation frequencies. Two tables were used; one for amino acid substitutions created in RT that increased the HIV-1 mutation rate and another for amino acid substitutions created in RT that decreased the HIV-1 mutation rate. The tables show which amino acid substitutions created in RT decreased or …

Developing A Quantitative Pcr Assay For Detecting Viral Vector Shedding From Animals, Swathee Chinnasamy

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Replication deficient viruses have been used widely for replacing, repairing, and deleting target genes. These recombinant viruses are tested on research animals or patients in clinical trials. Although viral vectors distribute in the body, they are also disseminated into the environment through secretion and excretion processes. By studying the extent of shedding, a proper risk assessment can be performed and appropriate biocontainment can be achieved. Adenoviral and lentiviral vectors were produced from commercially available kits. The transgene present in both vector systems was the lacZ reporter gene encoding for β-galactosidase. Primers and probes were designed for the encapsidation region of …