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Characterization of extracellular proteases of Acanthamoeba genotype T4 isolated from different sources in Iran
Behroz Mahdavi Poor1, Abdolhossein Dalimi2, Fatemeh Ghafarifar1
1Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, P. Box: 14115-111, Tehran, IR, Iran.
Abstract:
The members of the genus Acanthamoeba are ubiquitous, free-living amoebae found in various environments. The amoebae can cause severe complications in both, immunocompetent and immunocompromised individuals. The aim of this study was to characterize extracellular proteases of Acanthamoeba isolates from different sources belonging to genotype T4 as well as the determination of the pathogenicity potential to correlate pathogenicity with protease activity and protease banding pattern. A total of 19 isolates (11 clinical and 8 environmental) were cultured axenically, then the pathogenicity of the isolates was assessed by osmo- and thermo- tolerance tests. An applied colorimetric method using azocasein as a substrate was used for the extracellular protease activity assay. Protease characterization was carried out by zymography analysis with and without protease inhibitors. Assessment of the pathogenicity potential using physical parameters revealed that 2 (25%), 2 (25%), and 4 (50%) of the environmental isolates were potential pathogens, weak potential pathogens, and non-pathogens, respectively. According to our results, this protease activity assay can be a powerful tool for differentiating pathogenic and non-pathogenic strains of Acanthamoeba.
Insights
Extracellular proteases from Acanthamoeba genotype T4 isolates were characterized. Protease activity assays can differentiate pathogenic and non-pathogenic Acanthamoeba strains, aiding in understanding amoebic infections.
Area of Science:
- Microbiology
- Molecular Biology
- Parasitology
Background:
- Acanthamoeba are ubiquitous protozoa causing severe infections in humans.
- Extracellular proteases are virulence factors in Acanthamoeba pathogenesis.
- Genotype T4 is a common and clinically relevant Acanthamoeba type.
Purpose of the Study:
- To characterize extracellular proteases of Acanthamoeba genotype T4.
- To determine the pathogenicity potential of Acanthamoeba isolates.
- To correlate protease activity with pathogenicity.
Main Methods:
- Axenic culture of 19 Acanthamoeba isolates (11 clinical, 8 environmental).
- Pathogenicity assessment via osmo- and thermo- tolerance tests.
- Extracellular protease activity assay using azocasein substrate.
- Protease characterization by zymography with and without inhibitors.
Main Results:
- Environmental isolates showed varying pathogenicity: 25% potential pathogens, 25% weak pathogens, 50% non-pathogens.
- Protease activity assay demonstrated potential in differentiating pathogenic and non-pathogenic strains.
- Zymography provided insights into protease banding patterns and inhibitor susceptibility.
Conclusions:
- Extracellular protease activity is a potential biomarker for Acanthamoeba pathogenicity.
- Protease characterization aids in understanding virulence mechanisms.
- The protease activity assay is a valuable tool for distinguishing pathogenic Acanthamoeba strains.
