microbiology, Vol 141, 2301-2306, Copyright © 1995 by Society for General Microbiology

ARTICLES

An extreme creA mutation in Aspergillus nidulans has severe effects on D-glucose utilization

P van der Veen, GJ Ruijter and J Visser
Wageningen Agricultural University, Section of Molecular Genetics of Industrial Microorganisms, The Netherlands.

Aspergillus nidulans wild-type and the extreme carbon catabolite derepressed mutant creAd-30 were characterized with respect to enzyme activities, metabolite concentrations and polyol pools all related to glycolysis, after growth on D-glucose. In the creAd-30 strain the enzymes hexokinase and fructose-6-phosphate reductase showed a two- and threefold increase in activity, respectively, whereas phosphofructokinase and pyruvate kinase activity decreased two- and threefold, respectively, in comparison with the wild-type strain. The most notable changes in metabolite concentrations were that fructose 2,6-bisphosphate and fructose 1,6-bisphosphate showed a 2.5-fold increase, whereas both pyruvate and citrate decreased in the creAd-30. Striking differences were found for the polyol concentrations measured for the two strains tested. Intracellular glycerol and arabitol concentrations were 10-fold higher and erythritol fivefold higher in creAd-30, whereas intracellular trehalose and mannitol were both decreased. The total internal polyol concentration appears to be constant at approximately 700 mumol (g dry wt)-1. All polyols were also detected in high amounts in the culture filtrate of the creAd-30 mutant strain but no extracellular trehalose was found. The overall production of polyols in this strain was therefore much higher than in the wild- type. The high level of polyols produced and the changes in metabolite concentrations in the creAd-30 strain suggest that the differences in enzyme activities result in an altered flow through glycolysis leading to a more rapid formation of polyols which are subsequently secreted.

This article has been cited by other articles:

				H. David, A. M. Krogh, C. Roca, M. Akesson, and J. Nielsen CreA influences the metabolic fluxes of Aspergillus nidulans during growth on glucose and xylose Microbiology, July 1, 2005; 151(7): 2209 - 2221. [Abstract] [Full Text] [PDF]