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Cytosolic neutral proteinases of Paracoccidioides brasiliensis
G San-Blas1, F Sorais, G Niño-Vega
1Instituto Venezolano de Investigaciones Cientificas (IVIC), Centro de Microbiología y Biología Celular, Apartado 21827, Caracas 1020A, Venezuela.
Abstract:
Cytosolic proteinases were assayed in both morphological phases of Paracoccidioides brasiliensis. Preparations from the mycelial phase were more active in vitro than those from the yeast cells. Optimal proteinase activities for both phases occurred at pH's between 6.0 and 9.0, and at 45 degrees C. Gelatin-SDS-PAGE electrophoresis separated several bands (58-112 kDa) in mycelial preparations; a single band (70 kDa) was seen in yeast preparations. Enzymatic activities were inhibited by antipain, phenyl methyl sulfonyl fluoride (PMSF), and chymostatin, suggestive of serine proteinases. Partial inhibition of the mycelial enzymes by ethylene diamine tetraacetic acid (EDTA), 1,10-phenanthroline, and iodoacetamide, also suggested the presence of cysteine- and metallo-proteinases. The enzymatic activity increased in preparations extracted from yeast cells transforming to mycelia, and decreased in preparations obtained from the reverse process.
Insights
Paracoccidioides brasiliensis proteinase activity is higher in the mycelial phase. This study identifies potential serine, cysteine, and metallo-proteinases involved in its morphology.
Area of Science:
- Mycology
- Biochemistry
- Molecular Biology
Background:
- Paracoccidioides brasiliensis is a fungus causing paracoccidioidomycosis.
- Understanding its virulence factors, like proteinases, is crucial for disease control.
Purpose of the Study:
- To characterize cytosolic proteinase activity in both mycelial and yeast phases of P. brasiliensis.
- To identify the types of proteinases present and their optimal conditions.
Main Methods:
- Assay of cytosolic proteinase activity in mycelial and yeast forms.
- Gelatin-SDS-PAGE electrophoresis to analyze protein bands.
- Enzyme inhibition assays using specific inhibitors (PMSF, EDTA, etc.).
Main Results:
- Mycelial phase proteinases showed higher in vitro activity than yeast phase.
- Optimal activity for both phases was observed at pH 6.0-9.0 and 45°C.
- Inhibition patterns suggested the presence of serine, cysteine, and metallo-proteinases.
Conclusions:
- Cytosolic proteinases in P. brasiliensis are differentially active between morphological phases.
- The identified proteinases may play roles in fungal development and pathogenesis.
- Further research into these enzymes could reveal therapeutic targets.