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Pathogenic Microbiology Commons

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Full-Text Articles in Pathogenic Microbiology

Mechanism Of Candida Albicans Biofilm And Virulence Inhibition By A Bacterial Secreted Factor, Carrie Graham Dec 2017

Mechanism Of Candida Albicans Biofilm And Virulence Inhibition By A Bacterial Secreted Factor, Carrie Graham

UT GSBS Dissertations and Theses (Open Access)

The human microbiome is a diverse polymicrobial population comprised of both fungi and bacteria. Perturbations of the normal microbiome can have a profound impact on health, including the development of infections. Exploitation of these polymicrobial interactions has the potential to provide novel treatment and prevention strategies for infectious diseases. Enterococcus faecalis, a Gram-positive bacterium, and Candida albicans, a polymorphic fungus, occupy overlapping niches as ubiquitous constituents of the gastrointestinal and oral microbiome. Both species are also amongst the most important and problematic, opportunistic nosocomial pathogens and are often co-isolated during infection. Surprisingly, these two species antagonize each other’s virulence ...


The Roles Of Biotin In Candida Albicans Physiology, Nur Ras Aini Ahmad Hussin Nov 2016

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

Dissertations and Theses in Biological Sciences

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 ...


Dynamic Host-Pathogen Interactions Result In Fungal Epitope Unmasking, Alex Hopke Aug 2016

Dynamic Host-Pathogen Interactions Result In Fungal Epitope Unmasking, Alex Hopke

Electronic Theses and Dissertations

Molecular camouflage is used by a diverse set of pathogens to disguise their identity and avoid recognition by protective host receptors. The opportunistic fungal pathogen Candida albicans is a good example, as it masks the inflammatory component β-glucan in its cell wall to evade detection by the immune receptor Dectin-1. Interestingly, it has been seen that β-glucan becomes unmasked during infection in vivo, though the underlying mechanisms remained unclear. Exposure levels of this epitope may be important, as Dectin-1 mediates protection from some strains of C. albicans and alterations in the organization and composition of the Candida cell wall can ...


Characterization Of The Ato Gene Family In Alternative Carbon Metabolism, Heather A. Danhof May 2016

Characterization Of The Ato Gene Family In Alternative Carbon Metabolism, Heather A. Danhof

UT GSBS Dissertations and Theses (Open Access)

As a commensal colonizer and opportunistic pathogen, Candida albicans is the most clinically important human associated fungus. Systemic infection carries an unacceptably high mortality rate of ~40% in the growing population of immunocompromised individuals. Macrophages are important innate immune cells that limit the niches in the human body in which C. albicans can persist through phagocytic removal. However, following phagocytosis C. albicans readily escapes from the immune cell by differentiating into filamentous hyphae, a process that should be inhibited in the normally acidic phagolysosome. We have shown that C. albicans induces germination by neutralizing the phagolysosome. To better understand this ...


The Ccaat-Binding Factor Dependent Regulation Of The Oxidative Stress Response In Candida Albicans, Ananya Chakravarti May 2016

The Ccaat-Binding Factor Dependent Regulation Of The Oxidative Stress Response In Candida Albicans, Ananya Chakravarti

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 ...


The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis Aug 2015

The Role Of Phosphatidylserine And Phosphatidylethanolamine In Candida Albicans Virulence, Sarah Elizabeth Davis

Doctoral Dissertations

In hospitalized patients with neutropenia, Candida albicans is the fourth leading cause of systemic bloodstream infections, which have a mortality rate of approximately 30 %. The phosphatidylserine synthase enzyme of C. albicans, Cho1p, appears to be a good drug target as a mutant lacking this enzyme (the cho1Δ/Δ [null mutant]) is avirulent in animal models of Candida infections and this enzyme is not conserved in humans. We discovered that the loss of phosphatidylserine (PS) synthesis affects C. albicans' expression of the Als3p adhesin, a virulence protein, and loss of PS synthesis also compromises the cell wall, causing increased exposure ...


Regulation Of The Candida Albicans Arginine Biosynthetic Pathway, Claudia Jimenez Lopez May 2014

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

UT GSBS Dissertations and 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 ...


Farnesol Signaling In Candida Albicans, Melanie L. Langford Apr 2010

Farnesol Signaling In Candida Albicans, Melanie L. Langford

Dissertations and Theses in Biological Sciences

Candida albicans is a polymorphic fungus that causes a range of disease in humans, from mucosal infections to systemic disease. Its ability to cause disease is linked to conversion between yeast and filamentous forms of growth, and the first quorum-sensing molecule discovered in an eukaryote, farnesol, blocks this transition. In C. albicans, farnesol also kills mating-competent opaque cells, inhibits biofilm formation, protects the cells from oxidative stress, and can be a virulence factor or protective agent in disseminated and mucosal mouse models of infection, respectively. While much emphasis has been placed on determining its effect on C. albicans morphology, the ...


Candida Albicans Cellwall Components And Farnesol Stimulate The Expression Of Both Inflammatory And Regulatory Cytokines In The Murine Raw264.7 Macrophage Cell Line, Suman Ghosh, Nina Howe, Katie Volk, Swetha Tati, Kenneth W. Nickerson, Thomas M. Petro Jan 2010

Candida Albicans Cellwall Components And Farnesol Stimulate The Expression Of Both Inflammatory And Regulatory Cytokines In The Murine Raw264.7 Macrophage Cell Line, Suman Ghosh, Nina Howe, Katie Volk, Swetha Tati, Kenneth W. Nickerson, Thomas M. Petro

Kenneth Nickerson Papers

Candida albicans causes candidiasis, secretes farnesol, and switches from yeast to hyphae to escape from macrophages after phagocytosis. However, before escape, macrophages may respond to C. albicans’ pathogen-associated molecular patterns (PAMPs) through toll-like receptor 2 (TLR2) and dectin-1 receptors by expressing cytokines involved in adaptive immunity, inflammation, and immune regulation. Therefore, macrophages and the RAW264.7 macrophage line were challenged with C. albicans preparations of live wild-type cells, heat-killed cells, a live mutant defective in hyphae formation, a live mutant producing less farnesol, or an isolate producing farnesoic acid instead of farnesol. Interleukin-6 (IL-6), and IL-1b, IL- 10, and tumor ...


Genome-Wide Transcriptional Profiling Of The Cyclic Amp-Dependent Signaling Pathway During Morphogenic Transitions Of Candida Albicans, Yong-Sun Bahn, Matthew Molenda, Janet F. Staab, Courtney A. Lyman, Laura J. Gordon, Paula Sundstrom Dec 2007

Genome-Wide Transcriptional Profiling Of The Cyclic Amp-Dependent Signaling Pathway During Morphogenic Transitions Of Candida Albicans, Yong-Sun Bahn, Matthew Molenda, Janet F. Staab, Courtney A. Lyman, Laura J. Gordon, Paula Sundstrom

Open Dartmouth: Faculty Open Access Articles

Candida albicans is an opportunistic human fungal pathogen that causes systemic candidiasis as well as superficial mucosal candidiasis. In response to the host environment, C. albicans transitions between yeast and hyphal forms. In particular, hyphal growth is important in facilitating adhesion and invasion of host tissues, concomitant with the expression of various hypha-specific virulence factors. In previous work, we showed that the cyclic AMP (cAMP) signaling pathway plays a crucial role in morphogenic transitions and virulence of C. albicans by studying genes encoding adenylate cyclase-associated protein (CAP1) and high-affinity phosphodiesterase (PDE2) (Y. S. Bahn, J. Staab, and P. Sundstrom, Mol ...