Morphogenetic effect of L-cysteine on dermatophytes

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.