Detection of endogenous beta-glucuronidase activity in Aspergillus niger

Appl Microbiol Biotechnol. 1996 Mar;45(1-2):240-4. doi: 10.1007/s002530050677.

Abstract

An endogenous beta-glucuronidase that hydrolyses the chromogenic substrate 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-gluc) in Aspergillus niger is reported. The activity was induced when the fungus was grown in media containing xylan, but was either very low, or absent, when grown on glucose. Endogenous beta-glucuronidase was primarily located in newly formed hyphae, and was apparent at pH values between 3 and 6. Hydrolysis of X-gluc was sensitive to the inhibitor D-saccharic acid 1,4-lactone and was irreversibly inactivated by heating. The bacterial uid A beta-glucuronidase reporter gene was strongly expressed in the hyphae of transformed A. niger but, in contrast to the endogenous activity, the enzyme was also active at pH 7-8.5. Histochemical localization of uidA expression in A. niger, without interference from the endogenous beta-glucuronidase activity, was achieved by staining at this pH.

MeSH terms

  • Aspergillus niger / enzymology*
  • Aspergillus niger / genetics
  • Chromogenic Compounds
  • Escherichia coli / genetics
  • Genes, Bacterial
  • Genes, Reporter
  • Glucuronates
  • Glucuronidase / genetics
  • Glucuronidase / metabolism*
  • Indoles
  • Plasmids / genetics
  • Substrate Specificity
  • Transformation, Genetic

Substances

  • Chromogenic Compounds
  • Glucuronates
  • Indoles
  • 5-bromo-4-chloro-3-indolylglucuronide
  • Glucuronidase