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Synthesis of fluorochromes and pigments in Malassezia furfur by use of tryptophan as the single nitrogen source
Author(s) -
Mayser P.,
Wille G.,
Imkampe A.,
Thoma W.,
Arnold N.,
Monsees T.
Publication year - 1998
Publication title -
mycoses
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 69
eISSN - 1439-0507
pISSN - 0933-7407
DOI - 10.1111/j.1439-0507.1998.tb00336.x
Subject(s) - malassezia , pityriasis , pigment , biology , tryptophan , microbiology and biotechnology , agar , biochemistry , chemistry , amino acid , bacteria , immunology , genetics , organic chemistry
Summary. A new minimal medium consisting only of L‐tryptophan (L‐Trp) and a lipid source induced formation of brown pigmentation only in the species Malassezia furfur , which diffuses into the agar. Strains of the species M. sympodialis and M. pachydermatis failed to grow on this medium. On mDixon medium, however, after replacement of peptone by L‐Trp, growth of all three Malassezia species was achieved. Under these conditions pigment production was observed with all M. furfur strains tested, although the results for M. pachydermatis strains were inconsistent. M. sympodialis strains showed no pigment production. On the minimal medium pigmentogenesis was induced in M. furfur by only 0.01 g% tryptophan; the pH optimum was pH 5. In all M. furfur strains, alternative amino nitrogen sources given concurrently with Trp suppressed pigmentogenesis. Furthermore, there were differences in the optimal temperature among the individual M. furfur strains. CBS 7019, CBS 6000 and CBS 6001 failed to produce pigment at 37°C. The extract of the culture exhibited remarkable fluorescence, and several indole derivatives with a broad spectrum of colours were detected. This finding may have an impact on the clinical appearance of pityriasis versicolor, a very common skin disease caused by lipophilic yeasts of the genus Malassezia. We hypothesize that in pityriasis versicolor metabolic adaptation of Malassezia yeasts to altered nitrogen conditions on superficial skin might be of patho‐physiological importance. Tryptophan as an inducer of pigmentogenesis probably accumulates during excessive sweating, a well‐known manifestation of pityriasis versicolor. Zusammenfassung. Ausschließlich in der Species Malassezia furfur induzierte ein neues Minimalmedium, bestehend einzig aus L‐Tryptophan (L‐Trp) und einer Lipidquelle, die Bildung braunen Pigments, welches in den Agar diffundierte. Stämme der Species M. sympodialis und M. pachydermatis zeigten kein Wachstum auf diesem Nährboden. Auf mDixon Medium aber, in dem Pepton durch L‐Trp ersetzt wurde, zeigten alle drei Species Wachstum. Unter diesen Bedingungen wurde Pigmentbildung wiederum in M. furfur beobachtet, während die Ergebnisse für M. pachydermatis unein‐heitlich waren. M. sympodialis zeigte keine Pigment‐produktion. Auf Minimalmedium konnte die Pigmentbildung in M. furfur bereits mit 0,01 g% Trp induziert werden, das pH Optimum war pH 5. In allen M. furfur Stämmen konnte die Pigmentbildung durch gleichzeitge Gabe anderer Aminostik‐stoffquellen zusätzlich zu L‐Trp unterdrückt werden. Außerdem waren Differenzen in der optimalen Inkubationstemperatur zwischen den einzelnen M. furfur Stämmen zu beobachten. CBS 7019, CBS 6000 und CBS 6001 konnten bei 37°C kein Pigment produzieren. Das Extrakt aus der Kultur fluoreszierte deutlich, und einige Indol‐Derivate mit einem breiten Farbenspektrum