Two-dimensional electrophoresis of Malassezia allergens for atopic dermatitis and isolation of Mal f 4 homologs with mitochondrial malate dehydrogenase.
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The yeast Malassezia furfur is a natural inhabitant of the human skin microflora that induces an allergic reaction in atopic dermatitis. To identify allergens of M. furfur, we separated a crude preparation of M. furfur antigens as discrete spots by 2-D PAGE and detected IgE-binding proteins using sera of atopic dermatitis patients. We identified the known allergens, Mal f 2 and Mal f 3, and determined N-terminal amino acid sequences of six new IgE-binding proteins including Mal f 4. The cDNA and genomic DNA encoding Mal f 4 were cloned and sequenced. The gene was mitochondrial malate dehydrogenase and encoded Mal f 4 composed of 315 amino acids and a signal sequence of 27 amino acids. We purified Mal f 4, which had a molecular mass of 35 kDa from a membrane fraction of a lysate of cultured cells. Thirty of 36 M. furfur-allergic atopic dermatitis patients (83.3%) had elevated serum levels of IgE to purified Mal f 4, indicating that Mal f 4 is a major allergen. There was a significant correlation of the Phadebas RAST unit values of Mal f 4 and the crude antigen, but not between Mal f 4 and the known allergen Mal f 2. (+info)
Isolation of Malassezia furfur from a cat.
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During a survey of the occurrence of Malassezia species in the external ear canals of cats without otitis externa, Malassezia furfur was isolated. This is the first report of the isolation of M. furfur from cats. (+info)
The antifungal activity of mupirocin.
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The antibacterial agent mupirocin (pseudomonic acid A) is used as a topical agent in the treatment of superficial infections by Gram-positive bacteria, particularly Staphylococcus aureus. However, we demonstrate here that the compound also inhibits the growth of a number of pathogenic fungi in vitro, including a range of dermatophytes and Pityrosporum spp. It inhibited the incorporation of amino acids and precursors of RNA, but not that of acetate, by Trichophyton mentagrophytes. It also inhibited the isoleucyl-tRNA synthetase from Candida albicans, indicating a mechanism of action similar to that in bacteria. When administered topically, mupirocin was efficacious in a T. mentagrophytes ringworm model in guinea pigs. These results suggest that mupirocin could have clinical utility for superficial infections caused by dermatophytes. (+info)
Genetic diversity in the yeast species Malassezia pachydermatis analysed by multilocus enzyme electrophoresis.
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Fifty-two strains of the yeast species Malassezia pachydermatis were analysed by multilocus enzyme electrophoresis. M. pachydermatis appeared to be genetically heterogeneous. A total of 27 electrophoretic types were identified that could be divided into five distinct groups with different host specificities. The diversity revealed by this electrophoretic method matched remarkably well the reported genetic variability obtained by comparing large subunit rRNA sequences. This study also suggests that genetic exchanges can occur in the anamorphic species M. pachydermatis. (+info)
Selective cloning of allergens from the skin colonizing yeast Malassezia furfur by phage surface display technology.
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The yeast Malassezia furfur, also known as Pityrosporum orbiculare (ovale), is part of the normal microflora of the human skin but has also been associated with different skin diseases including atopic dermatitis. More than 50% of atopic dermatitis patients have positive skin test and specific IgE to M. furfur extracts; however, the pathophysiologic role of these IgE-mediated reactions in the development of the disease remains unknown. The yeast is able to produce a wide panel of IgE-binding proteins, variably recognized by sera of individual patients. In order to assess the contribution of individual components to the disease, highly pure allergen preparations are required. We have cloned M. furfur allergens from a cDNA library displayed on the phage surface, sequenced the inserts and produced recombinant proteins in Escherichia coli. Phage displaying IgE-binding proteins were selectively enriched from the library using IgE from a M. furfur-sensitized atopic dermatitis patient as a ligand. We were able to identify five different inserts coding for IgE-binding polypeptides. Three of the sequenced cDNA encode incomplete gene products with molecular masses of 21.3 kDa (MF 7), 14.4 kDa (MF 8), and 9.7 kDa (MF 9), respectively, having no sequence similarity to known proteins. The other two cDNA encode allergens of 18.2 kDa (Mal f 5) and 17.2 kDa (Mal f 6). Mal f 5 shows significant homology to M. furfur allergens Mal f 2, Mal f 3 and an Aspergillus fumigatus allergen Asp f 3. Mal f 6 has significant homology with cyclophilin. All of the recombinant polypeptides were capable of binding serum IgE from atopic dermatitis patients in immunoblotting experiments. The availability of pure recombinant M. furfur allergens will allow the careful investigation of the role of IgE-binding proteins in atopic dermatitis. (+info)
Species identification and strain typing of Malassezia species stock strains and clinical isolates based on the DNA sequences of nuclear ribosomal internal transcribed spacer 1 regions.
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This study demonstrated the application of internal transcribed spacer 1 (ITS1) ribosomal DNA sequences to the species identification and strain typing of 28 standard strains and 46 clinical isolates of the genus Malassezia. The size of ITS1 regions ranged from 162 to 266 bp. Members of the genus Malassezia (M. pachydermatis, M. furfur, M. sympodialis, M. globosa, M. obtusa, M. restricta and M. slooffiae) were classified into seven ITS1-homologous groups and 22 ITS1-identical, individual groups. The 46 clinical isolates of lipophilic Malassezia spp. were identified as belonging to just three ITS1-homologous groups, i.e., M. furfur (19 strains: 11 from pityriasis versicolor, 4 from seborrhoeic dermatitis and 4 from atopic dermatitis). M. sympodialis (22 strains: 7 from pityriasis versicolor, 3 from seborrhoeic dermatitis, 1 from atopic dermatitis and 11 from healthy controls) and M. slooffiae (five strains: three from chronic otitis media and two from healthy controls). (+info)
In vitro activities of ketoconazole, econazole, miconazole, and Melaleuca alternifolia (tea tree) oil against Malassezia species.
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The in vitro activities of ketoconazole, econazole, miconazole, and tea tree oil against 54 Malassezia isolates were determined by agar and broth dilution methods. Ketoconazole was more active than both econazole and miconazole, which showed very similar activities. M. furfur was the least susceptible species. M. sympodialis, M. slooffiae, M. globosa, and M. obtusa showed similar susceptibilities to the four agents. (+info)
Otitis externa associated with Malassezia sympodialis in two cats.
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The lipid-dependent species Malassezia sympodialis was isolated from two cats with otitis externa. To our knowledge, this is the first report of the isolation of lipid-dependent species of the genus Malassezia associated with skin disease in domestic animals. (+info)