Precipitate production by some Malassezia species on Dixon's agar

Hammer, Katherine A.; Riley, T. V.

doi:10.1080/714030932

Cited by 9 publications

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“…Besides their important role in biotechnology, these reactions have been discussed as potential virulence factors in pathogenic bacteria and fungi. Other studies have demonstrated the ability of M. furfur to release fatty acids from different lipids (Catterall et al, 1978;Hammer & Riley, 2000;Mancianti et al, 2001). Ran et al (1993) did not detect lipases in the supernatant, but determined that the main lipolytic activity was in the insoluble fraction of cell extracts.…”

Section: Introductionmentioning

confidence: 99%

MfLIP1, a gene encoding an extracellular lipase of the lipid-dependent fungus Malassezia furfur

Brunke

Hube

2006

Microbiology

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Malassezia furfur is a dimorphic fungus and a member of the normal cutaneous microflora of humans. However, it is also a facultative pathogen, associated with a wide range of skin diseases. One unusual feature of M. furfur is an absolute dependency on externally provided lipids which the fungus hydrolyses by lipolytic activity to release fatty acids necessary for both growth and pathogenicity. In this study, the cloning and characterization of the first gene encoding a secreted lipase of M. furfur possibly associated with this activity are reported. The gene, MfLIP1, shows high sequence similarity to other known extracellular lipases, but is not a member of a lipase gene family in M. furfur. MfLIP1 consists of 1464 bp, encoding a protein with a molecular mass of 54?3 kDa, a conserved lipase motif and an N-terminal signal peptide of 26 aa. By using a genomic library, two other genes were identified flanking MfLIP1, one of them encoding a putative secreted catalase, the other a putative amine oxidase. The cDNA of MfLIP1 was expressed in Pichia pastoris and the biochemical properties of the recombinant lipase were analysed. MfLip1 is most active at 40 6C and the pH optimum was found to be 5?8. The lipase hydrolysed lipids, such as Tweens, frequently used as the source of fatty acids in M. furfur media, and had minor esterase activity. Furthermore, the lipase is inhibited by different bivalent metal ions. This is the first molecular description of a secreted lipase from M. furfur.

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Section: Introductionmentioning

confidence: 99%

MfLIP1, a gene encoding an extracellular lipase of the lipid-dependent fungus Malassezia furfur

Brunke

Hube

2006

Microbiology

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“…Guillot et al reported a method of identification based on lipid usage pattern, catalase reaction, growth temperature, and cell shape (11). Hammer and Riley reported the production of a precipitate by some Malassezia strains on Dixon's agar (12); for example, M. furfur, M. obtusa, and M. slooffiae were precipitate-negative strains, while M. sympodialis and M. globosa were precipitate-positive strains. Mayser et al reported that some Malassezia species hydrolyzed esculin and assimilated polyethoxylated castor oil (Cremophor EL; Sigma, St. Louis, MO) (18), and these properties could be used to differentiate among species (8).…”

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confidence: 99%

Revised Culture-Based System for Identification of Malassezia Species

et al. 2007

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Forty-six strains of Malassezia spp. with atypical biochemical features were isolated from 366 fresh clinical isolates from human subjects and dogs. Isolates obtained in this study included 2 (4.7%) lipiddependent M. pachydermatis isolates; 1 (2.4%) precipitate-producing and 6 (14.6%) non-polyethoxylated castor oil (Cremophor EL)-assimilating M. furfur isolates; and 37 (34.3%) M. slooffiae isolates that were esculin hydrolyzing, 17 (15.7%) that were non-tolerant of growth at 40°C, and 2 (1.9%) that assimilated polyethoxylated castor oil. Although their colony morphologies and sizes were characteristic on CHROMagar Malassezia medium (CHROM), all strains of M. furfur developed large pale pink and wrinkled colonies, and all strains of M. slooffiae developed small (<1 mm) pale pink colonies on CHROM. These atypical strains were distinguishable by the appearance of their colonies grown on CHROM. Three clinically important Malassezia species, M. globosa, M. restricta, and M. furfur, were correctly identified by their biochemical characteristics and colony morphologies. The results presented here indicate that our proposed identification system will be useful as a routine tool for the identification of clinically important Malassezia species in clinical laboratories.Members of the genus Malassezia are among the microbiological flora of the skin of homoiothermic animals. Most species of this genus are lipid-dependent yeasts which colonize the seborrheic part of the skin, and they have been reported to be associated with pityriasis versicolor, seborrheic dermatitis, Malassezia folliculitis, and atopic dermatitis (1,6,19,20,24,29). Although M. furfur was previously thought to be the causative agent or trigger factor in all of these skin disorders, Guého et al. (9) reclassified this genus into five species in 1996. Malassezia has since been reclassified into seven species based on molecular biological analysis of nuclear ribosomal DNA/ RNA (9, 10), and the results agreed with those of mitochondrial ribosomal DNA analyses (30). As members of the genus Malassezia share similar morphological and biochemical characteristics, it was thought that differentiating between them based on phenotypic features would be difficult. While molecular biological techniques are the most reliable for the identification of Malassezia, they are not available in most clinical laboratories. Therefore, culture methods for the identification of Malassezia species are required. Some of these identification or differentiation methods have been reported previously. Guillot et al. reported a method of identification based on lipid usage pattern, catalase reaction, growth temperature, and cell shape (11). Hammer and Riley reported the production of a precipitate by some Malassezia strains on Dixon's agar (12); for example, M. furfur, M. obtusa, and M. slooffiae were precipitate-negative strains, while M. sympodialis and M. globosa were precipitate-positive strains. Mayser et al. reported that some Malassezia species hydrolyzed esculin and assimilated pol...

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“…Furthermore, utilization of the polyoxyethylated castor oil Cremophor EL (Sigma), hydrolysis of aesculin (Mayser et al, 1997) and precipitate production on mDixon agar (Hammer & Riley, 2000) were also examined.…”

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confidence: 99%

Malassezia nana sp. nov., a novel lipid-dependent yeast species isolated from animals

Hirai

Kano

Makimura

et al. 2004

International Journal of Systematic and Evolutionary Microbiology

201

130

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Five isolates of a novel species of the yeast genus Malassezia were isolated from animals in Japan and Brazil. Phylogenetic trees based on the D1/D2 domains of the large-subunit (26S) rDNA sequences and nucleotide sequences of the internal transcribed spacer 1 region showed that the isolates were conspecific and belonged to the genus Malassezia. They were related closely to Malassezia dermatis and Malassezia sympodialis, but were clearly distinct from these two species and the other six species of Malassezia that have been reported, indicating that they should be classified as a novel species, Malassezia nana sp. nov. Morphologically and physiologically, M. nana resembles M. dermatis and M. sympodialis, but can be distinguished from these species by its inability to use Cremophor EL (Sigma) as the sole lipid source and to hydrolyse aesculin. The type strain of M. nana is NUSV 1003 T (=CBS 9557 T =JCM 12085 T ).

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Precipitate production by some Malassezia species on Dixon's agar

Cited by 9 publications

References 0 publications

MfLIP1, a gene encoding an extracellular lipase of the lipid-dependent fungus Malassezia furfur

MfLIP1, a gene encoding an extracellular lipase of the lipid-dependent fungus Malassezia furfur

Revised Culture-Based System for Identification of Malassezia Species

Malassezia nana sp. nov., a novel lipid-dependent yeast species isolated from animals

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