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  • 1
    Digitale Medien
    Digitale Medien
    Morphometric and densitometric study of the biogenesis of electron-dense granules in Fonsecaea pedrosoi (1999)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 173 (1999), S. 0 
    Details
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Fonsecaea pedrosoi is a polymorphic pathogenic fungus, etiological agent of chromoblastomycosis, that synthesizes a melanin-like pigment. Although this pigment has been described as a component of the outer layers of the cell wall, electron-dense cytoplasmic bodies have also been visualized. In this work, we have correlated the appearance of intracellular electron-dense granules with the melanization process in F. pedrosoi. For this, conidial forms were grown under conditions where melanin was not synthesized. Afterwards, cells were incubated in Hank's medium supplemented with bovine fetal serum, at 37°C, to stimulate the pigment production. The genesis of cytoplasmic bodies, with different stages of electron density, was demonstrated by transmission electron microscopy. The appearance of fungal acidic compartments, visualized by confocal laser scanning microscopy in cells stained with acridine orange, was time coincident with the formation of electron-dense granules observed by transmission electron microscopy. The quantification of granule numbers as well as morphometric and densitometric studies were performed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1574-6968.1999.tb13531.x
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  • 2
    Digitale Medien
    Digitale Medien
    The role of surface carbohydrates on the interaction of microconidia of Trichophyton mentagrophytes with epithelial cells (2003)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS immunology and medical microbiology 35 (2003), S. 0 
    Details
    ISSN: 1574-695X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: The presence of carbohydrate-binding adhesins on the microconidia of Trichophyton mentagrophytes surface and their role on cellular interactions were investigated. Flow cytometry showed that this fungus recognizes the sugars mannose and galactose. The binding was inhibited by the addition of methyl α-d-mannopyranoside and methyl α-d-galactopyranoside, and showed higher fluorescence intensity at 37°C than 28°C. Trypsin treatment and heating of the cells reduced the binding, suggesting a (glyco) protein nature of the microconidia adhesin. The interaction of the fungus to Chinese hamster ovary epithelial cells and its glycosylation-deficient mutants demonstrated a higher adhesion index in Lec1 and Lec2 mutants, which express mannose and galactose, respectively, as the terminal carbohydrate on the cell surface. Endocytosed fungi were shown preferentially in Lec2 cells. Addition of the carbohydrates methyl α-d-mannopyranoside and methyl α-d-galactopyranoside to the interaction medium, pretreatment of Lec1 and Lec2 cells with lectins Concanavalina A and Arachis hypogaea and pretreatment with sodium periodate decreased the adhesion and the endocytic index. Examination of thin section by transmission electron microscopy showed that after fungal ingestion by Lec2 cells the fungi are enclosed in a ‘loose’-type vacuole while the other cells are found within a ‘tight’-type membrane-bound cytoplasmic vacuole. Our results suggest the occurrence of carbohydrate-specific adhesins on microconidia surface that recognize mannose and galactose. This may have a role in the adhesion process during the infectious process of dermatophytosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1016/S0928-8244(03)00007-5
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  • 3
    Digitale Medien
    Digitale Medien
    Comparison of Fonsecaea pedrosoi sclerotic cells obtained in vivo and in vitro: ultrastructure and antigenicity (2002)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS immunology and medical microbiology 33 (2002), S. 0 
    Details
    ISSN: 1574-695X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Medizin
    Notizen: The parasitic form of Fonsecaea pedrosoi from the hyperkeratotic layer of the skin was obtained from four patients with chromoblastomycosis. Primary cultures containing hyphae and conidia were successfully converted into sclerotic cells in the presence of 800 μM propranolol and low pH as described before [1]. The morphology of sclerotic cells of F. pedrosoi obtained in vivo and in vitro was analyzed by light and electron microscopy. Their antigenicity was also compared by immunofluorescence microscopy and ELISA assays, using serum samples from untreated patients infected with F. pedrosoi. Due to the similarity of the sclerotic cells obtained in vivo and in vitro, the latter can be more adequately in studies of host–parasite interactions in chromoblastomycosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1574-695X.2002.tb00574.x
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  • 4
    Digitale Medien
    Digitale Medien
    Chromoblastomycosis: a retrospective study of 325 cases on Amazonic Region (Brazil) (1998)
    Springer
    Mycopathologia 143 (1998), S. 171-175 
    Details
    ISSN: 1573-0832
    Schlagwort(e): Amazon ; chromoblastomycosis ; epidemiology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract A retrospective study of 325 cases of chromoblastomycosis diagnosed in the last 55 years in the Amazon region was carried out by the main Mycology services of the state of Pará, Brazil (Department of Tropical Pathology – UFPA and Mycology Department of the Evandro Chagas Institute/FNS). The data obtained showed that: (a) the main age group affected by the diseases range from 41 to 70 years-old, (b) 86.1% of the patients were agricultural-workers, (c) 93.2% of them were males and (d) 80.7% showed lesions on the lower limbs (feet and legs). The diagnosis of 62% of the cases was confirmed by laboratory studies considering the tissue form in histopathological analysis. In 24% of patients (78 cases), the etiological agent was isolated and identified through culture. Fonsecaea pedrosoi was present in 77 cases and Phialophora verucosa in only one case.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006957415346
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  • 5
    Digitale Medien
    Digitale Medien
    The influence of surface carbohydrates on the interaction of Fonsecaea pedrosoi with Chinese Hamster Ovary glycosylation mutant cells (1997)
    Springer
    Mycopathologia 138 (1997), S. 127-135 
    Details
    ISSN: 1573-0832
    Schlagwort(e): carbohydrate residues ; Chinese Hamster Ovary cells ; Fonsecaea pedrosoi ; interaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract In order to better understand the role played by surface glycoconjugates during cell adhesion and endocytosis by the dematiaceous fungi Fonsecaea pedrosoi, we analyzed the interaction between this microorganism and five mutants of Chinese Hamster Ovary (CHO) cells, which differ from each other in the exposition of carbohydrate residues on the cell surface. Five clones (Gat-2 parental, and the clones: Lec1, Lec2, Lec8 and ldlLec1) were tested and the adhesion and endocytic indexes were determined after 2 hours of interaction. The Lec1 and ldlLec1 clones, which present exposed mannose residues, showed the greater adhesion index (AI). On the other hand, the Lec8 clone, which exposes N-acetylglucosamine on the cell surface, presented the greater endocytic index. The role played by surface-exposed carbohydrate residues was further analyzed by addition of mannose or N-acetylglucosamine to the interaction medium and by previous incubation of the cells in the presence of the lectins Concanavalin A (ConA) and wheat germ agglutinin (WGA). The results obtained suggest that mannose residues are involved in the first step of adhesion of F. pedrosoi to the cell surface, while N-acetylglucosamine residues are involved on its ingestion process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006841529438
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  • 6
    Digitale Medien
    Digitale Medien
    The in vitro susceptibility ofFonsecaea pedrosoi to activated macrophages (1994)
    Springer
    Mycopathologia 126 (1994), S. 85-91 
    Details
    ISSN: 1573-0832
    Schlagwort(e): Activated-macrophages ; Fonsecaea pedrosoi ; NAD(P)H-oxidase ; Nitroblue tetrazolium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Light and electron microscopy were used to analyze in vitro the interaction ofFonsecaea pedrosoi with in vivo activated-macrophages. Adherence of the fungi to the surface of activated macrophages triggers the respiratory burst as revealed by reduction of nitroblue tetrazolium. Transmission electron microscopy revealed NAD(P)H-oxidase activity in the portions of the macrophage plasma of membrane that were in contact with the fungus as well as within phagocytic vacuoles. Activated macrophages failed to kill ingested fungi, but they showed a fungistatic activity delaying germ tube and hyphae formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01146200
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