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Full-Text Articles in Life Sciences

Identification And Characterization Of Genetic Factors Involved In Candida-Bacterial Interactions, Sean J. Fox Dec 2013

Identification And Characterization Of Genetic Factors Involved In Candida-Bacterial Interactions, Sean J. Fox

Electronic Theses and Dissertations

Throughout existence, fungi and bacteria have long shared ecological niches and thus engage in numerous interactions to mutually enhance survival or antagonistically gain competitive advantages. Of importance to human health are those interactions that involve bacteria with the opportunistic fungi, Candida albicans. An important virulence factor of C. albicans is the ability to control morphology, which allows the transition between yeast, pseudohyphal, and hyphal phenotypes. Morphological control in C. albicans is governed by quorum sensing and the secreted autoregulatory molecule farnesol. Quorum sensing allows individual cells to sense the environment and respond as a group. Bacteria also use quorum …


Development Of Novel Antifungal Peptides Based On A Natural Model Of Histatin-5 Peptide, Duy Tu Nguyen Dec 2013

Development Of Novel Antifungal Peptides Based On A Natural Model Of Histatin-5 Peptide, Duy Tu Nguyen

Graduate Theses and Dissertations

Our research group is working toward the development of novel antifungal peptides based on a natural model of peptide histatin-5. Histatin-5 is found in human saliva and known to protect our body against oral infections by Candida species. Candidiasis, or an infection caused by Candida species, is considered one of the most medically important fungal infections worldwide. Blood stream infections caused by Candida species are the fourth leading cause of hospital-acquired fungal infections that is associated with high mortality rates and high costs of treatment. This study investigated the modes of action of histatin-5 with the use of one 16-mer …


Differential Regulation Of White-Opaque Switching By Individual Subunits Of Candida Albicans Mediator, Anda Zhang, Zhongle Liu, Lawrence C. Myers Jul 2013

Differential Regulation Of White-Opaque Switching By Individual Subunits Of Candida Albicans Mediator, Anda Zhang, Zhongle Liu, Lawrence C. Myers

Dartmouth Scholarship

The multisubunit eukaryotic Mediator complex integrates diverse positive and negative gene regulatory signals and transmits them to the core transcription machinery. Mutations in individual subunits within the complex can lead to decreased or increased transcription of certain subsets of genes, which are highly specific to the mutated subunit. Recent studies suggest a role for Mediator in epigenetic silencing. Using white-opaque morphological switching in Candida albicans as a model, we have shown that Mediator is required for the stability of both the epigenetic silenced (white) and active (opaque) states of the bistable transcription circuit driven by the master regulator Wor1. Individual …


Use Of Image Cytometry For Quantification Of Pathogenic Fungi In Association With Host Cells, Charlotte A. Berkes, Leo Li-Ying Chan, Alisha Wilkinson, Benjamin Paradis Jun 2013

Use Of Image Cytometry For Quantification Of Pathogenic Fungi In Association With Host Cells, Charlotte A. Berkes, Leo Li-Ying Chan, Alisha Wilkinson, Benjamin Paradis

Biology Faculty Publications

Studies of the cellular pathogenesis mechanisms of pathogenic yeasts such as Candida albicans, Histoplasma capsulatum, and Cryptococcus neoformans commonly employ infection of mammalian hosts or host cells (i.e. macrophages) followed by yeast quantification using colony forming unit analysis or flow cytometry. While colony forming unit enumeration has been the most commonly used method in the field, this technique has disadvantages and limitations, including slow growth of some fungal species on solid media and low and/or variable plating efficiencies, which is of particular concern when comparing growth of wild-type and mutant strains. Flow cytometry can provide rapid quantitative information regarding yeast …


Evolutionary And Molecular Analysis Of Conserved Vertebrate Immunity To Fungi, Erin Carter May 2013

Evolutionary And Molecular Analysis Of Conserved Vertebrate Immunity To Fungi, Erin Carter

Honors College

The innate immune system is highly conserved amongst all multicellular organisms. Yet a constant battle exists between host cells and pathogens due to the rapid evolution of immune system components. Functional genomics and in silico methods can be employed to elucidate the evolutionary patterns of vertebrate immunity to pathogenic fungi such as Candida albicans, an opportunistic fungal pathogen that can cause lethal candidiasis in the immunocompromised. Mammals such as humans and mice possess conserved C-type lectin receptors that recognize the C. albicans cell wall. However, these receptors have not been identified in fish. Here I describe how we identified potential …


Correction: Differential Adaptation Of Candida Albicans In Vivo Modulates Immune Recognition By Dectin-1, Mohlopheni J. Marakalala, Simon Vautier, Joanna Potrykus, Louise A. Walker, Kelly M. Shepardson, Alex Hopke, Hector M. Mora-Montes, Ann Kerrigan, Mihai G. Netea, Graeme I. Murray, Donna M. Maccallum, Robert Wheeler, Carol A. Munro, Neil A. R Gow, Robert A. Cramer, Alistair J. P Brown, Gordon D. Brown Apr 2013

Correction: Differential Adaptation Of Candida Albicans In Vivo Modulates Immune Recognition By Dectin-1, Mohlopheni J. Marakalala, Simon Vautier, Joanna Potrykus, Louise A. Walker, Kelly M. Shepardson, Alex Hopke, Hector M. Mora-Montes, Ann Kerrigan, Mihai G. Netea, Graeme I. Murray, Donna M. Maccallum, Robert Wheeler, Carol A. Munro, Neil A. R Gow, Robert A. Cramer, Alistair J. P Brown, Gordon D. Brown

Dartmouth Scholarship

The b -glucan receptor Dectin-1 is a member of the C-type lectin family and functions as an innate pattern recognition receptor in antifungal immunity. In both mouse and man, Dectin-1 has been found to play an essential role in controlling infections with Candida albicans , a normally commensal fungus in man which can cause superficial mucocutaneous infections as well as life-threatening invasive diseases. Here, using in vivo models of infection, we show that the requirement for Dectin-1 in the control of systemic Candida albicans infections is fungal strain-specific; a phenotype that only becomes apparent during infection and cannot be recapitulated …


Control Of Candida Albicans Metabolism And Biofilm Formation By Pseudomonas Aeruginosa Phenazines, Diana K. Morales, Nora Grahl, Chinweike Okegbe, Lars E. P. Dietrich, Nicholas J. Jacobs, Deborah A. Hogan Jan 2013

Control Of Candida Albicans Metabolism And Biofilm Formation By Pseudomonas Aeruginosa Phenazines, Diana K. Morales, Nora Grahl, Chinweike Okegbe, Lars E. P. Dietrich, Nicholas J. Jacobs, Deborah A. Hogan

Dartmouth Scholarship

Candidaalbicanshasdevelopmentalprogramsthatgoverntransitionsbetweenyeastandfilamentousmorphologies and between unattached and biofilm lifestyles. Here, we report that filamentation, intercellular adherence, and biofilm develop- ment were inhibited during interactions between Candida albicans and Pseudomonas aeruginosa through the action of P. aeruginosa-produced phenazines. While phenazines are toxic to C. albicans at millimolar concentrations, we found that lower concentrations of any of three different phenazines (pyocyanin, phenazine methosulfate, and phenazine-1-carboxylate) allowed growth but affected the development of C. albicans wrinkled colony biofilms and inhibited the fungal yeast-to-filament transition. Phenazines impaired C. albicans growth on nonfermentable carbon sources and led to increased production of fer- mentation products (ethanol, glycerol, and …


Candida Albicans Induces Arginine Biosynthetic Genes In Response To Host-Derived Reactive Oxygen Species, Claudia Jimenez-Lopez, John R. Collette, Kimberly M. Brothers, Kelly M. Shepardson, Robert A. Kramer Jan 2013

Candida Albicans Induces Arginine Biosynthetic Genes In Response To Host-Derived Reactive Oxygen Species, Claudia Jimenez-Lopez, John R. Collette, Kimberly M. Brothers, Kelly M. Shepardson, Robert A. Kramer

Dartmouth Scholarship

The interaction of Candida albicans with phagocytes of the host's innate immune system is highly dynamic, and its outcome directly impacts the progression of infection. While the switch to hyphal growth within the macrophage is the most obvious physiological response, much of the genetic response reflects nutrient starvation: translational repression and induction of alternative carbon metabolism. Changes in amino acid metabolism are not seen, with the striking exception of arginine biosynthesis, which is upregulated in its entirety during coculture with macrophages. Using single-cell reporters, we showed here that arginine biosynthetic genes are induced specifically in phagocytosed cells. This induction is …


Reporters For The Analysis Of N-Glycosylation In Candida Albicans, Shahida Shahana, Hector M. Mora-Montes, Luis Castillo, Iryna Bohovych, Chirag C. Sheth, Frank C. Odds, Neil A.R. Gow, Alistair J.P. Brown Jan 2013

Reporters For The Analysis Of N-Glycosylation In Candida Albicans, Shahida Shahana, Hector M. Mora-Montes, Luis Castillo, Iryna Bohovych, Chirag C. Sheth, Frank C. Odds, Neil A.R. Gow, Alistair J.P. Brown

Department of Biochemistry: Faculty Publications

A large proportion of Candida albicans cell surface proteins are decorated post-translationally by glycosylation. Indeed N-glycosylation is critical for cell wall biogenesis in this major fungal pathogen and for its interactions with host cells. A detailed understanding of N-glycosylation will yield deeper insights into host-pathogen interactions. However, the analysis of N-glycosylation is extremely challenging because of the complexity and heterogeneity of these structures. Therefore, in an attempt to reduce this complexity and facilitate the analysis of N-glycosylation, we have developed new synthetic C. albicans reporters that carry a single N-linked glycosylation site derived from Saccharomyces cerevisiae Suc2. These …


Fungal Peritonitis In Dog Caused By Candida Albicans - A Case Report And Literature Overview, Kamila Glinska, Marcin Jankowski, Krzysztof Kubiak, Jolanta Spuzak, Maciej Grzegory, Stanislaw Dzimira Jan 2013

Fungal Peritonitis In Dog Caused By Candida Albicans - A Case Report And Literature Overview, Kamila Glinska, Marcin Jankowski, Krzysztof Kubiak, Jolanta Spuzak, Maciej Grzegory, Stanislaw Dzimira

Turkish Journal of Veterinary & Animal Sciences

This clinical case concerns a male dog of Pointer breed, 10 years of age. The clinical examination revealed severe tenderness and a tension in the abdominal walls. The ultrasound examination detected fluid in the peritoneal cavity. The fluid collected from the peritoneal cavity displayed typical features of exudative fluid. In the cytological examination of the fluid, numerous stimulated endothelial cells, lymphocytes, and neutrophils were found. In the microbiological examination of the peritoneal fluid, Candida albicans was cultured. On the basis of the clinical signs, laboratory test results of the peritoneal fluid, and microbiological culture, the diagnosis of fungal peritonitis was …