The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Jiangye Chen - One of the best experts on this subject based on the ideXlab platform.
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Asc1, a WD-repeat protein, is required for Hyphal development and virulence in Candida albicans
Acta biochimica et biophysica Sinica, 2010Co-Authors: Xiaoyan Liu, Xinyi Nie, Yufeng Ding, Jiangye ChenAbstract:Candida albicans is a human pathogenic fungus which can undergo a morphological transition from yeast to Hyphae in response to a variety of environmental stimuli. We analyzed a C. albicans Asc1 (Absence of growth Suppressor of Cyp1) protein which is entirely composed of seven repeats of the WD domain, and is conserved from fungi to metazoan. Deleting the ASC1 in C. albicans led to a profound defect in Hyphal development under Hypha-inducing conditions examined. Furthermore, deletion of the ASC1 attenuated virulence of C. albicans in a mouse model of systemic infection. These data strongly suggested that the conserved WD-repeat protein Asc1 is required for morphogenesis and pathogenesis of C. albicans.
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efg1 mediated recruitment of nua4 to promoters is required for Hypha specific swi snf binding and activation in candida albicans
Molecular Biology of the Cell, 2008Co-Authors: Xuming Mao, Prashna Pala Raniga, Haoping Liu, Jiangye ChenAbstract:Efg1 is essential for Hyphal development and virulence in the human pathogenic fungus Candida albicans. How Efg1 regulates gene expression is unknown. Here, we show that Efg1 interacts with components of the nucleosome acetyltransferase of H4 (NuA4) histone acetyltransferase (HAT) complex in both yeast and Hyphal cells. Deleting YNG2, a subunit of the NuA4 HAT module, results in a significant decrease in the acetylation level of nucleosomal H4 and a profound defect in Hyphal development, as well as a defect in the expression of Hypha-specific genes. Using chromatin immunoprecipitation, Efg1 and the NuA4 complex are found at the UAS regions of Hypha-specific genes in both yeast and Hyphal cells, and Efg1 is required for the recruitment of NuA4. Nucleosomal H4 acetylation at the promoters peaks during initial Hyphal induction in an Efg1-dependent manner. We also find that Efg1 bound to the promoters of Hypha-specific genes is critical for recruitment of the Swi/Snf chromatin remodeling complex during Hyphal induction. Our data show that the recruitment of the NuA4 complex by Efg1 to the promoters of Hypha-specific genes is required for nucleosomal H4 acetylation at the promoters during Hyphal induction and for subsequent binding of Swi/Snf and transcriptional activation.
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Efg1-mediated Recruitment of NuA4 to Promoters Is Required for Hypha-specific Swi/Snf Binding and Activation in Candida albicans
Molecular biology of the cell, 2008Co-Authors: Xuming Mao, Prashna Pala Raniga, Haoping Liu, Jiangye ChenAbstract:Efg1 is essential for Hyphal development and virulence in the human pathogenic fungus Candida albicans. How Efg1 regulates gene expression is unknown. Here, we show that Efg1 interacts with components of the nucleosome acetyltransferase of H4 (NuA4) histone acetyltransferase (HAT) complex in both yeast and Hyphal cells. Deleting YNG2, a subunit of the NuA4 HAT module, results in a significant decrease in the acetylation level of nucleosomal H4 and a profound defect in Hyphal development, as well as a defect in the expression of Hypha-specific genes. Using chromatin immunoprecipitation, Efg1 and the NuA4 complex are found at the UAS regions of Hypha-specific genes in both yeast and Hyphal cells, and Efg1 is required for the recruitment of NuA4. Nucleosomal H4 acetylation at the promoters peaks during initial Hyphal induction in an Efg1-dependent manner. We also find that Efg1 bound to the promoters of Hypha-specific genes is critical for recruitment of the Swi/Snf chromatin remodeling complex during Hyphal induction. Our data show that the recruitment of the NuA4 complex by Efg1 to the promoters of Hypha-specific genes is required for nucleosomal H4 acetylation at the promoters during Hyphal induction and for subsequent binding of Swi/Snf and transcriptional activation.
Thomas Boller - One of the best experts on this subject based on the ideXlab platform.
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Hyphal in vitro growth of the arbuscular mycorrhizal fungus Glomus mosseae is affected by chitinase but not by β-1,3-glucanase.
Mycorrhiza, 2001Co-Authors: Horst Vierheilig, Andres Wiemken, Thomas BollerAbstract:Purified basic chitinase or β-1,3-glucanase or a combination of the two enzymes were applied to Hyphae of the arbuscular mycorrhizal fungus Glomus mosseae grown in vitro. Chitinase applied to the Hyphal tip produced an inhibition of Hyphal extension, lysis of the apex and alterations of the growth pattern of the fungus. No effect was observed, however, when chitinase was applied to subapical parts of the Hyphae or when glucanase was applied to any part of the Hyphae. Application of a combination of the two enzymes to the Hyphal tip produced an effect similar to that of chitinase alone.
Sergio Grinstein - One of the best experts on this subject based on the ideXlab platform.
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candida albicans Hyphal expansion causes phagosomal membrane damage and luminal alkalinization
Mbio, 2018Co-Authors: Johannes Westman, Gary P Moran, Selene Mogavero, Bernhard Hube, Sergio GrinsteinAbstract:ABSTRACT Macrophages rely on phagosomal acidity to destroy engulfed microorganisms. To survive this hostile response, opportunistic fungi such as Candida albicans developed strategies to evade the acidic environment. C. albicans is polymorphic and able to convert from yeast to Hyphae, and this transition is required to subvert the microbicidal activity of the phagosome. However, the phagosomal lumen, which is acidic and nutrient deprived, is believed to inhibit the yeast-to-Hypha transition. To account for this apparent paradox, it was recently proposed that C. albicans produces ammonia that alkalinizes the phagosome, thus facilitating yeast-to-Hypha transition. We reexamined the mechanism underlying phagosomal alkalinization by applying dual-wavelength ratiometric pH measurements. The phagosomal membrane was found to be highly permeable to ammonia, which is therefore unlikely to account for the pH elevation. Instead, we find that yeast-to-Hypha transition begins within acidic phagosomes and that alkalinization is a consequence of proton leakage induced by excessive membrane distension caused by the expanding Hypha. IMPORTANCEC. albicans is the most common cause of nosocomial fungal infection, and over 3 million people acquire life-threatening invasive fungal infections every year. Even if antifungal drugs exist, almost half of these patients will die. Despite this, fungi remain underestimated as pathogens. Our study uses quantitative biophysical approaches to demonstrate that yeast-to-Hypha transition occurs within the nutrient-deprived, acidic phagosome and that alkalinization is a consequence, as opposed to the cause, of Hyphal growth.
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candida albicans Hyphal expansion causes phagosomal membrane damage and luminal alkalinization
bioRxiv, 2018Co-Authors: Johannes Westman, Gary P Moran, Selene Mogavero, Bernhard Hube, Sergio GrinsteinAbstract:Macrophages rely on phagosomal acidity to destroy engulfed microorganisms. To survive this hostile response, opportunistic fungi such as Candida albicans developed strategies to evade the acidic environment. C. albicans is polymorphic, able to convert from yeast to Hyphae, and this transition is required to subvert the microbicidal activity of the phagosome. However, the phagosomal lumen, which is acidic and nutrient-deprived, inhibits yeast-to-Hypha transition. To account for this apparent paradox, it was recently proposed that C. albicans produces ammonia that alkalinizes the phagosome, thus facilitating yeast-to-Hypha transformation. We re-examined the mechanism underlying phagosomal alkalinization by applying dual-wavelength ratiometric pH measurements. The phagosomal membrane was found to be highly permeable to ammonia, which is therefore unlikely to account for the pH elevation. Instead, we find that yeast-to-Hypha transition begins within acidic phagosomes, and that alkalinization is a consequence of proton leakage induced by excessive membrane distension caused by the expanding Hypha.
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Candida albicans Hyphal Expansion Causes Phagosomal Membrane Damage and Luminal Alkalinization
American Society for Microbiology, 2018Co-Authors: Johannes Westman, Selene Mogavero, Bernhard Hube, Gary Moran, Sergio GrinsteinAbstract:C. albicans is the most common cause of nosocomial fungal infection, and over 3 million people acquire life-threatening invasive fungal infections every year. Even if antifungal drugs exist, almost half of these patients will die. Despite this, fungi remain underestimated as pathogens. Our study uses quantitative biophysical approaches to demonstrate that yeast-to-Hypha transition occurs within the nutrient-deprived, acidic phagosome and that alkalinization is a consequence, as opposed to the cause, of Hyphal growth.Macrophages rely on phagosomal acidity to destroy engulfed microorganisms. To survive this hostile response, opportunistic fungi such as Candida albicans developed strategies to evade the acidic environment. C. albicans is polymorphic and able to convert from yeast to Hyphae, and this transition is required to subvert the microbicidal activity of the phagosome. However, the phagosomal lumen, which is acidic and nutrient deprived, is believed to inhibit the yeast-to-Hypha transition. To account for this apparent paradox, it was recently proposed that C. albicans produces ammonia that alkalinizes the phagosome, thus facilitating yeast-to-Hypha transition. We reexamined the mechanism underlying phagosomal alkalinization by applying dual-wavelength ratiometric pH measurements. The phagosomal membrane was found to be highly permeable to ammonia, which is therefore unlikely to account for the pH elevation. Instead, we find that yeast-to-Hypha transition begins within acidic phagosomes and that alkalinization is a consequence of proton leakage induced by excessive membrane distension caused by the expanding Hypha
Marie A Elliot - One of the best experts on this subject based on the ideXlab platform.
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function and redundancy of the chaplin cell surface proteins in aerial Hypha formation rodlet assembly and viability in streptomyces coelicolor
Journal of Bacteriology, 2008Co-Authors: Christina Di Berardo, David S Capstick, Mark J Buttner, Marie A Elliot, Maureen J. Bibb, Kim FindlayAbstract:The chaplins are a family of eight secreted proteins that are critical for raising aerial Hyphae in Streptomyces coelicolor. These eight chaplins can be separated into two main groups: the long chaplins (ChpA to -C) and the short chaplins (ChpD to -H). The short chaplins can be further subdivided on the basis of their abilities to form intramolecular disulfide bonds: ChpD, -F, -G, and -H contain two Cys residues, while ChpE has none. A “minimal chaplin strain” containing only chpC, chpE, and chpH was constructed and was found to raise a substantial aerial mycelium. This strain was used to examine the roles of specific chaplins. Within this strain, the Cys-containing ChpH was identified as the major polymerization unit contributing to aerial Hypha formation and assembly of an intricate rodlet ultrastructure on the aerial surfaces, and the two Cys residues were determined to be critical for its function. ChpC augmented aerial Hypha formation and rodlet assembly, likely by anchoring the short chaplins to the cell surface, while ChpE was essential for the viability of wild-type S. coelicolor. Interestingly, the lethal effects of a chpE null mutation could be suppressed by the loss of the other chaplins, the inactivation of the twin arginine translocation (Tat) secretion pathway, or the loss of the rodlins. The gram-positive soil-dwelling streptomycetes have a mycelial growth habit that culminates in the formation of dormant exospores that permit survival under adverse environmental conditions (13). Germinating spores produce one or more germ tubes that grow by tip extension to form a network of branching vegetative Hyphae known as the vegetative mycelium. Antibiotics (and other secondary metabolites) are produced within the vegetative Hyphae, and from this vegetative mycelial network emerge specialized reproductive structures known as aerial Hyphae. These aerial Hyphae undergo a number of maturation steps, including a synchronous round of cell division, to differentiate into chains of unigenomic spores. The transition from vegetative growth in an aqueous environment to the emergence of aerial Hyphae into the air requires significant adaptation of the cell surface: the surfaces of vegetative Hyphae are hydrophilic, while those of aerial Hyphae and spores are extremely hydrophobic. Three groups of proteins are known to be involved in the modulation of cell surfaces during aerial Hypha formation in Streptomyces coelicolor: the chaplins, the rodlins, and SapB (reviewed in references 8, 16, and 36). These proteins are thought to collectively function like the fungal hydrophobins, which are important for surface modulation and aerial growth in the filamentous fungi (reviewed in reference 37). Hydrophobins are small secreted proteins that assemble
Horst Vierheilig - One of the best experts on this subject based on the ideXlab platform.
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Hyphal in vitro growth of the arbuscular mycorrhizal fungus Glomus mosseae is affected by chitinase but not by β-1,3-glucanase.
Mycorrhiza, 2001Co-Authors: Horst Vierheilig, Andres Wiemken, Thomas BollerAbstract:Purified basic chitinase or β-1,3-glucanase or a combination of the two enzymes were applied to Hyphae of the arbuscular mycorrhizal fungus Glomus mosseae grown in vitro. Chitinase applied to the Hyphal tip produced an inhibition of Hyphal extension, lysis of the apex and alterations of the growth pattern of the fungus. No effect was observed, however, when chitinase was applied to subapical parts of the Hyphae or when glucanase was applied to any part of the Hyphae. Application of a combination of the two enzymes to the Hyphal tip produced an effect similar to that of chitinase alone.
