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BETA-GLUCOSIDASE SYSTEM OF NEUROSPORA CRASSA. I. BETA-GLUCOSIDASE AND CELLULASE ACTIVITIES OF MUTANT AND WILD-TYPE
Journal of Bacteriology
|April 1, 1964
Summary
Researchers identified a Neurospora crassa mutant (gluc-1) with reduced beta-glucosidase activity. This study reveals two complementary beta-glucosidases, one thermolabile and one thermostable, crucial for enzyme function.
Area of Science:
- Biochemistry
- Molecular Biology
- Mycology
Background:
- Neurospora crassa possesses a complex beta-glucosidase system.
- Understanding enzyme activity in fungal mutants is key to metabolic pathway elucidation.
Purpose of the Study:
- To isolate and characterize a mutant strain of Neurospora crassa with altered beta-glucosidase activity.
- To investigate the roles of different beta-glucosidase enzymes in wild-type and mutant strains.
Main Methods:
- Irradiation of Neurospora crassa to induce mutations.
- Screening for extracellular beta-glucosidase activity and esculin hydrolysis.
- Enzyme assays on mycelial and conidial extracts under varying temperatures.
- Ammonium fractionation for enzyme separation.
Main Results:
- A mutant strain, gluc-1, exhibiting significantly reduced beta-glucosidase activity was isolated.
- Two distinct beta-glucosidases were identified: one thermolabile (mycelia only) and one thermostable (mycelia and conidia).
- The gluc-1 mutation specifically affects the thermostable beta-glucosidase, while thermolabile activity and cellulase remain unaffected.
Conclusions:
- Neurospora crassa utilizes at least two complementary beta-glucosidases for efficient substrate utilization.
- The gluc-1 mutation provides a tool to differentiate and study the functions of these distinct beta-glucosidase enzymes.
- The thermostable beta-glucosidase is essential for growth on certain carbon sources and is differentially expressed in mycelia and conidia.