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A morphological mutant of Paracoccidioides brasiliensis strain IVIC Pb9. Isolation and wall characterization
Abstract:
A morphological mutant of Paracoccidioides brasiliensis strain IVIC Pb9 was isolated after treatment of the yeast-like (Y) form with nitrosoguanidine. Colonies of the mutant grown at room temperature did not show the whitish cotton-like morphology typical of the mycelial form of the parental strain. Y-cells were much smaller than those produced by the parent and grew forming chains of different sizes. The main chemical difference in the wall of the Y-form was the replacement of the alpha-I,3-glucan, typical of the parental strain, by an amorphous I,3-mannan in the mutant.
Insights
Researchers developed a Paracoccidioides brasiliensis mutant with altered cell wall composition. This yeast-like mutant exhibits distinct morphological and chemical differences compared to the parent strain.
Area of Science:
- Medical Mycology
- Microbial Genetics
- Biochemistry
Background:
- Paracoccidioides brasiliensis is a fungus causing paracoccidioidomycosis.
- Understanding fungal morphology and cell wall composition is crucial for developing antifungal strategies.
- Chemical and morphological variations can impact fungal virulence and drug susceptibility.
Purpose of the Study:
- To isolate and characterize a morphological mutant of Paracoccidioides brasiliensis.
- To investigate the chemical differences in the cell wall of the mutant yeast-like form.
- To compare the morphology of the mutant with the parental strain.
Main Methods:
- Chemical mutagenesis of Paracoccidioides brasiliensis strain IVIC Pb9 using nitrosoguanidine.
- Cultivation of the yeast-like (Y) form at room temperature.
- Microscopic observation of cell morphology and colony characteristics.
- Chemical analysis of the cell wall composition.
Main Results:
- A morphological mutant was successfully isolated.
- The mutant's colonies lacked the typical cotton-like mycelial morphology.
- Mutant Y-cells were smaller and formed chains, differing from the parent strain.
- The mutant's cell wall showed replacement of alpha-I,3-glucan with amorphous I,3-mannan.
Conclusions:
- Nitrosoguanidine treatment can induce significant morphological and chemical changes in Paracoccidioides brasiliensis.
- The mutant exhibits a unique cell wall composition, replacing alpha-I,3-glucan with I,3-mannan.
- These findings contribute to understanding the genetic and biochemical basis of Paracoccidioides brasiliensis morphology.