[Dimorphism in "Ustilago cynodontis". II--Glucidic metabolism (author's transl)]

Abstract

The glucidic metabolism has been studied in four strains of Ustilago cynodontis. Two of them--M1 and M7--are mycelial strains, the two others --L1 and L7--being yeast like are respectively issued from M1 and M7. The results obtained show that the choice between the different glucidic catabolism pathways takes place at the phosphofructokinase level. When the phosphofructokinase is lacking (M1) the catabolism occurs via the pentose phosphate cycle followed by the last glycolytic reactions (between triose-phosphates and pyruvic acid). When the phosphofructokinase is present it always enters into competition with a very active phosphoglucose isomerase which makes it ineffective (L1, M7, L7). In those cases the catabolism still proceeds through the pentose cycle either completely (L7) or incompletely (L1, M7), depending in the presence or the absence of transketolase. In the last case it is the phosphoketolases which carry out the conversion between fructose-5-phosphate, xylulose-6-phosphate and acetyl-phosphate.