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Morphogenetic effect of L-cysteine on dermatophytes
Abstract:
In the presence of L-cysteine, all the 24 dermatophyton fungi under study grew poorly. None of the strains, except Trichophyton menatographytes var. quinckeanum, grew in the presence of 0.04 M L-cysteine. The strains growing on a medium containing L-cysteine showed morphological changes. The surface of the colonies lost its velvety appearance and became awnless or waxy. The strains grown in the presence of L-cysteine abundantly formed chlamydospores. The chains of chlamydospores may resemble yeast cell chains, but true budding forms were not found in cultures in vitro. If strains precultivated on L-cysteine-containing medium were injected intraperitoneally into mice budding forms appeared in the peritoneal fluid.
Insights
L-cysteine significantly inhibited dermatophyte fungi growth, causing morphological changes and abundant chlamydospore formation. Budding forms, not seen in vitro, appeared in mice after L-cysteine precultivation.
Area of Science:
- Mycology
- Medical Microbiology
- Dermatophyte Research
Background:
- Dermatophytes are fungi causing superficial infections.
- Nutritional requirements influence fungal growth and morphology.
- L-cysteine's role in dermatophyte metabolism is not fully understood.
Purpose of the Study:
- To investigate the effect of L-cysteine on dermatophyte growth and morphology.
- To determine the inhibitory concentration of L-cysteine for dermatophyte strains.
- To observe morphological alterations in dermatophytes exposed to L-cysteine.
Main Methods:
- Culturing 24 dermatophyte strains on media with varying L-cysteine concentrations.
- Microscopic examination of fungal morphology, including colony surface and spore formation.
- In vivo studies involving intraperitoneal injection of L-cysteine-precultivated strains into mice.
Main Results:
- L-cysteine markedly inhibited the growth of 23 out of 24 dermatophyte strains.
- A concentration of 0.04 M L-cysteine prevented growth in most strains, except Trichophyton mentagrophytes var. quinckeanum.
- Morphological changes included loss of velvety texture, development of waxy colonies, and abundant chlamydospore formation; in vivo, budding forms were observed.
Conclusions:
- L-cysteine acts as a potent growth inhibitor for most dermatophyte species.
- The presence of L-cysteine induces significant morphological changes, including chlamydospore production.
- L-cysteine-induced morphological changes may include yeast-like budding forms, particularly evident in vivo.