The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform
Christine M Coyle - One of the best experts on this subject based on the ideXlab platform.
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an ergot alkaloid biosynthesis gene and clustered hypothetical genes from aspergillus fumigatus
Applied and Environmental Microbiology, 2005Co-Authors: Christine M Coyle, Daniel G PanaccioneAbstract:The ergot alkaloids are a family of indole-derived mycotoxins with a variety of significant biological activities. Aspergillus fumigatus, a common Airborne Fungus and opportunistic human pathogen, and several fungi in the relatively distant taxon Clavicipitaceae (clavicipitaceous fungi) produce different sets of ergot alkaloids. The ergot alkaloids of these divergent fungi share a four-member ergoline ring but differ in the number, type, and position of the side chains. Several genes required for ergot alkaloid production are known in the clavicipitaceous fungi, and these genes are clustered in the genome of the ergot Fungus Claviceps purpurea. We investigated whether the ergot alkaloids of A. fumigatus have a common biosynthetic and genetic origin with those of the clavicipitaceous fungi. A homolog of dmaW, the gene controlling the determinant step in the ergot alkaloid pathway of clavicipitaceous fungi, was identified in the A. fumigatus genome. Knockout of dmaW eliminated all known ergot alkaloids from A. fumigatus, and complementation of the mutation restored ergot alkaloid production. Clustered with dmaW in the A. fumigatus genome are sequences corresponding to five genes previously proposed to encode steps in the ergot alkaloid pathway of C. purpurea, as well as additional sequences whose deduced protein products are consistent with their involvement in the ergot alkaloid pathway. The corresponding genes have similarities in their nucleotide sequences, but the orientations and positions within the cluster of several of these genes differ. The data indicate that the ergot alkaloid biosynthetic capabilities in A. fumigatus and the clavicipitaceous fungi had a common origin.
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abundant respirable ergot alkaloids from the common Airborne Fungus aspergillus fumigatus
Applied and Environmental Microbiology, 2005Co-Authors: Daniel G Panaccione, Christine M CoyleAbstract:Ergot alkaloids are mycotoxins that interact with several monoamine receptors, negatively affecting cardiovascular, nervous, reproductive, and immune systems of exposed humans and animals. Aspergillus fumigatus, a common Airborne Fungus and opportunistic human pathogen, can produce ergot alkaloids in broth culture. The objectives of this study were to determine if A. fumigatus accumulates ergot alkaloids in a respirable form in or on its conidia, to quantify ergot alkaloids associated with conidia produced on several different substrates, and to measure relevant physical properties of the conidia. We found at least four ergot alkaloids, fumigaclavine C, festuclavine, fumigaclavine A, and fumigaclavine B (in order of abundance), associated with conidia of A. fumigatus. Under environmentally relevant conditions, the total mass of ergot alkaloids often constituted >1% of the mass of the conidium. Ergot alkaloids were extracted from conidia produced on all media tested, and the greatest quantities were observed when the Fungus was cultured on latex paint or cultured maize seedlings. The values for physical properties of conidia likely to affect their respirability (i.e., diameter, mass, and specific gravity) were significantly lower for A. fumigatus than for Aspergillus nidulans, Aspergillus niger, and Stachybotrys chartarum. The demonstration of relatively high concentrations of ergot alkaloids associated with conidia of A. fumigatus presents opportunities for investigations of potential contributions of the toxins to adverse health effects associated with the Fungus and to aspects of the biology of the Fungus that contribute to its success.
Daniel G Panaccione - One of the best experts on this subject based on the ideXlab platform.
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an ergot alkaloid biosynthesis gene and clustered hypothetical genes from aspergillus fumigatus
Applied and Environmental Microbiology, 2005Co-Authors: Christine M Coyle, Daniel G PanaccioneAbstract:The ergot alkaloids are a family of indole-derived mycotoxins with a variety of significant biological activities. Aspergillus fumigatus, a common Airborne Fungus and opportunistic human pathogen, and several fungi in the relatively distant taxon Clavicipitaceae (clavicipitaceous fungi) produce different sets of ergot alkaloids. The ergot alkaloids of these divergent fungi share a four-member ergoline ring but differ in the number, type, and position of the side chains. Several genes required for ergot alkaloid production are known in the clavicipitaceous fungi, and these genes are clustered in the genome of the ergot Fungus Claviceps purpurea. We investigated whether the ergot alkaloids of A. fumigatus have a common biosynthetic and genetic origin with those of the clavicipitaceous fungi. A homolog of dmaW, the gene controlling the determinant step in the ergot alkaloid pathway of clavicipitaceous fungi, was identified in the A. fumigatus genome. Knockout of dmaW eliminated all known ergot alkaloids from A. fumigatus, and complementation of the mutation restored ergot alkaloid production. Clustered with dmaW in the A. fumigatus genome are sequences corresponding to five genes previously proposed to encode steps in the ergot alkaloid pathway of C. purpurea, as well as additional sequences whose deduced protein products are consistent with their involvement in the ergot alkaloid pathway. The corresponding genes have similarities in their nucleotide sequences, but the orientations and positions within the cluster of several of these genes differ. The data indicate that the ergot alkaloid biosynthetic capabilities in A. fumigatus and the clavicipitaceous fungi had a common origin.
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abundant respirable ergot alkaloids from the common Airborne Fungus aspergillus fumigatus
Applied and Environmental Microbiology, 2005Co-Authors: Daniel G Panaccione, Christine M CoyleAbstract:Ergot alkaloids are mycotoxins that interact with several monoamine receptors, negatively affecting cardiovascular, nervous, reproductive, and immune systems of exposed humans and animals. Aspergillus fumigatus, a common Airborne Fungus and opportunistic human pathogen, can produce ergot alkaloids in broth culture. The objectives of this study were to determine if A. fumigatus accumulates ergot alkaloids in a respirable form in or on its conidia, to quantify ergot alkaloids associated with conidia produced on several different substrates, and to measure relevant physical properties of the conidia. We found at least four ergot alkaloids, fumigaclavine C, festuclavine, fumigaclavine A, and fumigaclavine B (in order of abundance), associated with conidia of A. fumigatus. Under environmentally relevant conditions, the total mass of ergot alkaloids often constituted >1% of the mass of the conidium. Ergot alkaloids were extracted from conidia produced on all media tested, and the greatest quantities were observed when the Fungus was cultured on latex paint or cultured maize seedlings. The values for physical properties of conidia likely to affect their respirability (i.e., diameter, mass, and specific gravity) were significantly lower for A. fumigatus than for Aspergillus nidulans, Aspergillus niger, and Stachybotrys chartarum. The demonstration of relatively high concentrations of ergot alkaloids associated with conidia of A. fumigatus presents opportunities for investigations of potential contributions of the toxins to adverse health effects associated with the Fungus and to aspects of the biology of the Fungus that contribute to its success.
Marc Thilo Figge - One of the best experts on this subject based on the ideXlab platform.
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automated image analysis of the host pathogen interaction between phagocytes and aspergillus fumigatus
PLOS ONE, 2011Co-Authors: Franziska Mech, Reinhard Guthke, Andreas Thywisen, Axel A Brakhage, Marc Thilo FiggeAbstract:Aspergillus fumigatus is a ubiquitous Airborne Fungus and opportunistic human pathogen. In immunocompromised hosts, the Fungus can cause life-threatening diseases like invasive pulmonary aspergillosis. Since the incidence of fungal systemic infections drastically increased over the last years, it is a major goal to investigate the pathobiology of A. fumigatus and in particular the interactions of A. fumigatus conidia with immune cells. Many of these studies include the activity of immune effector cells, in particular of macrophages, when they are confronted with conidia of A. fumigus wild-type and mutant strains. Here, we report the development of an automated analysis of confocal laser scanning microscopy images from macrophages coincubated with different A. fumigatus strains. At present, microscopy images are often analysed manually, including cell counting and determination of interrelations between cells, which is very time consuming and error-prone. Automation of this process overcomes these disadvantages and standardises the analysis, which is a prerequisite for further systems biological studies including mathematical modeling of the infection process. For this purpose, the cells in our experimental setup were differentially stained and monitored by confocal laser scanning microscopy. To perform the image analysis in an automatic fashion, we developed a ruleset that is generally applicable to phagocytosis assays and in the present case was processed by the software Definiens Developer XD. As a result of a complete image analysis we obtained features such as size, shape, number of cells and cell-cell contacts. The analysis reported here, reveals that different mutants of A. fumigatus have a major influence on the ability of macrophages to adhere and to phagocytose the respective conidia. In particular, we observe that the phagocytosis ratio and the aggregation behaviour of pksP mutant compared to wild-type conidia are both significantly increased.
Li Zhi-qiang - One of the best experts on this subject based on the ideXlab platform.
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Survey of Airborne Fungus in Wuhan Area
Chinese Journal of Allergy and Clinical Immunology, 2009Co-Authors: Li Zhi-qiangAbstract:Objective To investigate the variety of the Airborne Fungus in Wuhan area and study the relationships between Airborne Fungus and allergic diseases. Methods We surveyed the Fungus sensitizing of air in Wuhan city from Feb.1th, 2007 to Jau.31th, 2008 to quantitatively observe the daily Airborne Fungus and count under microscope through one year. Result The Fungus spores were present through all year. More than 20 types of Airborne Fungus have been collected, among which the most common Fungus were Uredinales, Ustilaginales, Alternaria, etc. Fungus spores were related with the season and weather, the most abandoned period in spring and summer. Conclusion The Airborne Fungus were seen one year and were mostly allergenic. Many of them had seasonal distribution.
M K Agarwal - One of the best experts on this subject based on the ideXlab platform.
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physico chemical and clinico immunologic studies on the allergenic significance of aspergillus tamarii a common Airborne Fungus
Immunobiology, 2011Co-Authors: Maansi Vermani, Vannan Kandi Vijayan, Balakrishnan Menon, Mohd Adnan Kausar, M K AgarwalAbstract:Abstract Aspergillus -derived inhalant allergens play an important role in the etiology of allergic respiratory diseases. In the present study, we investigated the allergenic potential of Aspergillus tamarii , quantified its Airborne content, identified its major/minor allergens, evaluated heterogeneity of patients’ IgE response to its allergens and cross-reactivity of its allergens with other Aspergillus allergens. Skin prick tests with A tamarii extract were performed on 300 patients of bronchial asthma/allergic rhinitis and 20 healthy volunteers. Sixty-six patients (22%) elicited positive cutaneous reactions to A tamarii extract. Only one of the 20 non-allergic healthy volunteer showed a mild positive cutaneous reaction. Allergen-specific IgE levels increased with increase in patients’ cutaneous response (0% in negative to 100% in 3+/4+). The skin positivity and allergen-specific IgE levels were significantly higher in patients compared to healthy volunteers ( P > 0.05). However, no differences were found for these two parameters among patients of bronchial asthma, allergic rhinitis and bronchial asthma with allergic rhinitis. The Airborne A tamarii allergen content was highest in February and October. A tamarii extract revealed at least 22 proteins (13.3–120 kDa). Seventeen of these proteins bound patients’ IgE with six being major allergens (13.3, 23, 25, 34, 39.5, 43 kDa). Three major allergens (13.3, 34, 43 kDa) were found to cross-react with A flavus and one (34 kDa) with A niger . Our results revealed that A tamarii allergen(s) are present in the air, which might serve as important inhalant allergens in IgE-mediated allergic respiratory diseases.