Regulation of invertase in Aspergillus nidulans: effect of different carbon sources.
Aspergillus nidulans produces an extracellular beta-D-fructofuranoside fructohydrolase (invertase) when grown on a medium containing the beta-fructofuranosides sucrose or raffinose, indicating that synthesis is subject to induction by the substrate. On a growth medium containing sucrose, production was maximal at 15 h in cultures incubated at 28 C degrees. After this time the level of detectable invertase in the cultures declined. A proportion of the enzyme was secreted during the linear growth phase of the fungus. Various sugars were investigated for induction of invertase, but only the two beta-fructofuranosides induced high production levels; with the other sugars, the enzyme was produced only at a low constitutive level. Mycelium grown under repressive conditions (1% glucose), rapidly produced invertase when transferred to sucrose-containing medium. After 80 min the invertase level in these cultures was 26-fold higher than the constitutive level. The repressive effect of other sugars, e.g. glucose and xylose, on invertase production was also demonstrated in this experimental system.
Vainstein
M H
MH
Department of Botany, University of Nottingham, UK.
Peberdy
J F
JF
D001233:Aspergillus nidulans / Q000201:enzymology* / Q000254:growth & development; D002241:Carbohydrates / Q000494:pharmacology*; D003470:Culture Media; D004790:Enzyme Induction; D004794:Enzyme Repression; D005632:Fructose / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000096:biosynthesis*; D013395:Sucrose / Q000494:pharmacology; D014994:Xylose / Q000494:pharmacology; D043324:beta-Fructofuranosidase
D002241:Carbohydrates; D003470:Culture Media; D005632:Fructose; D013395:Sucrose; D014994:Xylose; D006026:Glycoside Hydrolases; D043324:beta-Fructofuranosidase; D005947:Glucose