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Updated: Sep 27, 2026
Mucin Agarose Gel Electrophoresis: Western Blotting for High-molecular-weight Glycoproteins
Published on: June 14, 2016
Extracellular proteolysis by Mucoraceae in serum-albumin agar tested by the agar block method
1Mycology Unit, Robert Koch Institute, Berlin, Germany.
Abstract:
In a preliminary study, three strains of Absidia corymbifera (two strains from autopsy material of the lungs and one from the soil of a potted indoor plant in a hospital) and one strain of Rhizopus oryzae (from the soil of a potted plant in a hospital) were tested for secretory proteolytic activity in serum-albumin agar (SAA) with initial pH values of 5.0 and 7.0 by the agar block method and subsequent protein staining. Within an incubation period of 5 d/37 degrees C, complete proteolysis took place in all the SAA blocks with an initial pH value of 7.0. The three strains of Absidia corymbifera and the one strain of Rhizopus oryzae did not fully proteolyse the SAA blocks with an initial pH value of 5.0. On the basis of these observations, it is assumed that there are secretory proteases in the causative agents of mucormycosis (zygomycosis) whose optimal pH is not in the acid but in the neutral, perhaps in the alkaline range.
Insights
This study investigated secretory proteolytic activity in Absidia corymbifera and Rhizopus oryzae. Proteases from these mucormycosis agents showed optimal activity at neutral pH, not acidic.
Area of Science:
- Mycology
- Biochemistry
- Medical Microbiology
Background:
- Mucormycosis (zygomycosis) is a serious fungal infection.
- The causative agents, including Absidia corymbifera and Rhizopus oryzae, possess secretory enzymes.
- Understanding the enzymatic activity of these fungi is crucial for disease management.
Purpose of the Study:
- To determine the secretory proteolytic activity of Absidia corymbifera and Rhizopus oryzae strains.
- To investigate the optimal pH for protease activity in these fungal species.
Main Methods:
- Utilized serum-albumin agar (SAA) to assess proteolytic activity.
- Employed the agar block method with initial pH values of 5.0 and 7.0.
- Incubated samples at 37°C for 5 days and analyzed protein degradation via staining.
Main Results:
- Complete proteolysis of SAA was observed at pH 7.0 for all tested strains.
- Partial proteolysis occurred at pH 5.0, indicating reduced activity in acidic conditions.
- Both Absidia corymbifera and Rhizopus oryzae demonstrated significant proteolytic activity at neutral pH.
Conclusions:
- Secretory proteases produced by Absidia corymbifera and Rhizopus oryzae function optimally in neutral to alkaline conditions.
- These findings suggest that the optimal pH for these fungal proteases is not acidic.
- This has implications for understanding the pathogenesis of mucormycosis.
