Study of the glucoamylase promoter in Aspergillus niger using green fluorescent protein.
An Aspergillus niger strain expressing a red-shifted green fluorescent protein (GFP) in the cytoplasm under the control of the glucoamylase promoter (PgIaA) was characterized with respect to its physiology and morphology. Although xylose acted as a repressor carbon source during batch cultivations, PgIaA-driven GFP expression by the glucoamylase promoter could be demonstrated in xylose-limited continuous cultures. In these cultivations, the xylose concentration was therefore too low to cause repression. Transient experiments initiated with a maltose pulse did not further induce red-shifted GFP production in xylose-limited continuous cultures. Maltose induction under conditions of xylose repression was microscopically observed and quantified in a flow-through chamber. Red-shifted GFP was first produced after 5 h induction. Finally the strain was characterized in glucose-limited continuous cultures, and here the area of the mycelium stained with cytoplasmic GFP increased with increasing specific growth rate, indicating that GFP can be used as a marker of cellular activity in this type of cultivation.
Henriksen
Anne L Santerre
ALS
Center for Process Biotechnology, Building 223, Technical University of Denmark, DK-2800 Lyngby, Denmark.
Even
Sergine
S
Center for Process Biotechnology, Building 223, Technical University of Denmark, DK-2800 Lyngby, Denmark.
Müller
Christian
C
Center for Process Biotechnology, Building 223, Technical University of Denmark, DK-2800 Lyngby, Denmark.
Punt
Peter J
PJ
TNO Nutrition and Food Research Institute, Department of Molecular Genetics and Gene Technology, PO Box 360, NL-3700 AJ Zeist, The Netherlands.
van den Hondel
Cees A M J J
CAMJJ
TNO Nutrition and Food Research Institute, Department of Molecular Genetics and Gene Technology, PO Box 360, NL-3700 AJ Zeist, The Netherlands.
Nielsen
Jens
J
Center for Process Biotechnology, Building 223, Technical University of Denmark, DK-2800 Lyngby, Denmark.
D001234:Aspergillus niger / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D017930:Genes, Reporter; D005087:Glucan 1,4-alpha-Glucosidase / Q000235:genetics*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic
D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D005087:Glucan 1,4-alpha-Glucosidase