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Degradation of aflatoxin by Aspergillus flavus
1Department of Bioscience and Biotechnology, University of Strathclyde, Glasgow, UK.
Abstract:
Aflatoxin degradative activity was demonstrated in 6- to 12-d-old intact mycelium and cell-free extracts of Aspergillus flavus. The addition of cycloheximide, SKF 525-A or metyrapone to cultures of A. flavus prevented subsequent degradation of the aflatoxins, while in cell-free extracts degradation was inhibited by SKF 525-A, metyrapone and cytochrome c but not by KCN. In cell-free extracts, aflatoxin degradation was enhanced by NADPH and NaIO4. The results suggest the involvement of cytochrome P-450 monooxygenases in the aflatoxin degradative activity of A. flavus.
Insights
Aspergillus flavus degrades aflatoxins using enzymes. Inhibitors suggest cytochrome P-450 monooxygenases are involved in this detoxification process.
Area of Science:
- Microbiology
- Mycology
- Biochemistry
Background:
- Aflatoxins are toxic secondary metabolites produced by Aspergillus species.
- Understanding aflatoxin degradation is crucial for food safety and agriculture.
Purpose of the Study:
- To investigate the mechanisms of aflatoxin degradation by Aspergillus flavus.
- To identify the enzymatic pathways involved in aflatoxin detoxification.
Main Methods:
- Assessing aflatoxin degradation in intact Aspergillus flavus mycelium and cell-free extracts.
- Using enzyme inhibitors (cycloheximide, SKF 525-A, metyrapone, cytochrome c, KCN) to probe degradation pathways.
- Evaluating the effect of cofactors (NADPH, NaIO4) on degradation activity.
Main Results:
- Aflatoxin degradation was observed in both intact mycelium and cell-free extracts of Aspergillus flavus.
- Degradation was inhibited by specific enzyme inhibitors, suggesting enzymatic involvement.
- Cytochrome P-450 monooxygenases were implicated due to inhibition patterns and enhancement by NADPH and NaIO4.
Conclusions:
- Aspergillus flavus possesses the capability to degrade aflatoxins.
- Cytochrome P-450 monooxygenases play a significant role in the aflatoxin degradation pathway of Aspergillus flavus.