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Adaptation of Aspergillus niger to several antifungal agents
1Department of Biotechnology, Faculty of Technology, Tokyo University of Agriculture and Technology, Japan.
Abstract:
Adaptation of Aspergillus niger to short-term stress induced by three antifungal agents [amphotericin B (AMPH), miconazole (MCZ), and ketoconazole (KCZ)] was observed and evaluated quantitatively using individual hyphae. Spores were inoculated onto a poly-L-lysine-coated glass plate making up the base of a culture vessel. Potato dextrose broth (PDB) was added and the vessel incubated for 24 h at 28 degrees C. The growth rate of an arbitrarily selected test hypha was measured automatically. Exposure to AMPH (0.075 micrograms ml-1) stopped the growth of the hypha. After washing with PDB, the same concentration of AMPH was applied again. The growth of the test hypha was not inhibited. This phenomenon was defined as adaptation to the short-term stress of AMPH. Similarly, adaptation was observed with MCZ (0.01 microgram ml-1) and KCZ (0.5 microgram ml-1). The time required for the test hypha to restart growth after washing with PDB depended upon the concentration of MCZ or KCZ, but not upon the concentration of AMPH.
Insights
Aspergillus niger rapidly adapts to antifungal agents like amphotericin B, miconazole, and ketoconazole. This adaptation allows the fungus to resume growth even after initial stress exposure.
Area of Science:
- Mycology
- Antifungal Resistance
- Microbial Adaptation
Background:
- Aspergillus niger is a common fungus with clinical relevance.
- Antifungal agents are crucial for treating fungal infections.
- Understanding fungal adaptation mechanisms is vital for developing effective treatments.
Purpose of the Study:
- To investigate the short-term adaptation of Aspergillus niger to three antifungal agents.
- To quantitatively evaluate the adaptation process using individual hyphae.
- To determine the influence of different antifungal agents on adaptation.
Main Methods:
- Inoculating Aspergillus niger spores on a coated glass plate in a culture vessel.
- Incubating cultures in potato dextrose broth (PDB) for 24 hours at 28°C.
- Measuring hyphal growth rates automatically and exposing hyphae to antifungal agents (amphotericin B, miconazole, ketoconazole) followed by washing and re-exposure.
Main Results:
- Exposure to amphotericin B (AMPH), miconazole (MCZ), and ketoconazole (KCZ) induced adaptation in Aspergillus niger hyphae.
- Adapted hyphae resumed growth after washing and re-exposure to the same antifungal concentrations.
- The time for growth recovery varied with MCZ and KCZ concentrations but not AMPH concentration.
Conclusions:
- Aspergillus niger exhibits rapid adaptation to short-term stress from common antifungal agents.
- This adaptive response suggests potential mechanisms for antifungal resistance development.
- Further research into these adaptation pathways is warranted for clinical applications.