Related Experiment Videos
Characterization of a Schizosaccharomyces pombe morphological mutant altered in the galactomannan content
1Instituto de Microbiología Bioquímica, Universidad de Salamanca, Facultad de Biología, Spain.
Abstract:
In a search for Schizosaccharomyces pombe mutants resistant to the antifungal agent papulacandin B, a morphological mutant was isolated. The mutant is round shaped in contrast to the rod shaped parental strain. This morphological defect segregated as a recessive Mendelian character and was not observed in other papulacandin B resistant mutants belonging to the same complementation group. The mutation mapped in the right arm of S. pombe chromosome III very close to pap1 marker. Mutant cell walls were more susceptible to alkali extraction and Novozyme degradation than those from the wild-type. A specific reduction in the cell wall galactomannan fraction was the only significant difference detected as compared to the wild-type strain. Levels of beta (1,3)-glucan and mannan synthases as well as other enzymic periplasmic mannoproteins were very similar in wild type and mutant strains.
Insights
A Schizosaccharomyces pombe mutant resistant to papulacandin B exhibits a round shape due to reduced cell wall galactomannan. This finding offers insights into antifungal resistance mechanisms and cell wall biosynthesis.
Area of Science:
- * Mycology and Fungal Genetics
- * Cell Wall Biology
- * Antifungal Drug Discovery
Background:
- * Schizosaccharomyces pombe is a model organism for studying eukaryotic cell biology.
- * Papulacandin B is an antifungal agent that targets fungal cell wall synthesis.
- * Understanding mechanisms of antifungal resistance is crucial for developing new therapies.
Purpose of the Study:
- * To isolate and characterize Schizosaccharomyces pombe mutants resistant to papulacandin B.
- * To investigate the genetic and biochemical basis of a specific morphological defect in a resistant mutant.
- * To identify alterations in cell wall composition associated with papulacandin B resistance.
Main Methods:
- * Mutagenesis screen for papulacandin B resistance in S. pombe.
- * Genetic analysis including segregation and mapping of the mutation.
- * Biochemical analysis of cell wall composition and enzyme activity.
Main Results:
- * Isolation of a recessive morphological mutant with a round shape, distinct from the wild-type rod shape.
- * The mutation mapped to chromosome III near the pap1 marker and segregated independently of papulacandin B resistance in other mutants.
- * Mutant cell walls showed increased susceptibility to alkali extraction and Novozyme degradation, with a significant reduction in the galactomannan fraction.
- * Enzyme levels for beta-(1,3)-glucan and mannan synthases remained similar between wild-type and mutant strains.
Conclusions:
- * The identified mutation affects cell wall galactomannan content, leading to morphological changes and altered cell wall integrity.
- * This galactomannan deficiency is linked to papulacandin B resistance in this specific S. pombe mutant.
- * The study highlights the role of galactomannan in maintaining cell wall structure and susceptibility to antifungal agents.