Expression of elastinolytic activity among isolates in Aspergillus section flavi

Area of Science:

• Mycology
• Enzymology
• Biochemistry

Background:

• Elastinolytic potential is a characteristic of certain fungi.
• Previous studies indicated variability in elastase production among Aspergillus Section Flavi species.
• Borate buffers were previously used to assess elastase activity.

Purpose of the Study:

• To survey the distribution of elastinolytic potential in Aspergillus Section Flavi.
• To investigate the impact of buffer systems on elastase detection.
• To characterize the types of elastinolytic proteinases present.

Main Methods:

• Screening of fungal isolates from culture collections and environmental samples.
• Comparison of elastase detection using borate versus HEPES buffers.
• Analysis of elastase activity in liquid cultures.
• Isoelectric focusing and enzyme inhibition assays to identify proteinase types.

Main Results:

• Elastase production was highly conserved across Aspergillus Section Flavi, with most A. flavus isolates showing activity.
• Replacing borate with HEPES buffer significantly improved elastase detection, identifying activity in nearly all isolates.
• Elastase activity in liquid culture was primarily observed in A. flavus, A. tamarii, and A. oryzae.
• Enzyme inhibition studies suggested the presence of both metallo and serine elastinolytic proteinases.

Conclusions:

• Elastase production is a conserved trait in Aspergillus Section Flavi, with detection being sensitive to buffer choice.
• HEPES buffer is superior to borate for detecting fungal elastase activity.
• The identified elastinolytic activity involves a combination of metallo and serine proteinases.