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Detection of endogenous beta-glucuronidase activity in Aspergillus niger
T E Gottschalk1, J E Nielsen, P Rasmussen
1Danisco Biotechnology, Copenhagen K, Denmark.
Applied Microbiology and Biotechnology
|March 1, 1996
Summary
Researchers discovered an endogenous beta-glucuronidase in Aspergillus niger, active during xylan growth. This enzyme
Area of Science:
- Mycology
- Enzymology
- Molecular Biology
Background:
- Aspergillus niger possesses an endogenous beta-glucuronidase enzyme.
- This enzyme hydrolyzes the chromogenic substrate 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-gluc).
Purpose of the Study:
- To characterize the endogenous beta-glucuronidase in Aspergillus niger.
- To investigate the expression and localization of the bacterial uidA reporter gene in A. niger.
Main Methods:
- Fungal growth on different media (xylan vs. glucose).
- Enzyme activity assays using X-gluc substrate.
- Histochemical staining for beta-glucuronidase activity.
- Expression of the uidA reporter gene in transformed A. niger.
Main Results:
- Endogenous beta-glucuronidase activity was induced by xylan and primarily located in new hyphae (pH 3-6).
- Activity was inhibited by D-saccharic acid 1,4-lactone and heat-inactivated.
- Bacterial uidA gene expression was strong in hyphae and active at higher pH (7-8.5).
- Histochemical localization of uidA expression was achieved at pH 7-8.5, avoiding interference from endogenous activity.
Conclusions:
- Characterization of endogenous beta-glucuronidase in Aspergillus niger provides insights into fungal physiology.
- The uidA reporter gene can be effectively used for studying gene expression in A. niger at neutral to alkaline pH.