BIOCHEMICAL STUDIES ON COCHLIOBOLUS MIYABEANUS: VII. CELLULAR CARBOHYDRATE AS AN ENDOGENOUS SUBSTRATE FOR CONIDIA GERMINATION IN COCHLIOBOLUS MIYABEANUS

The carbohydrate content in the conidia of Cochliobolus miyabeanuswas found to be about 32% of the dry conidia, approximately70 per cent of which was composed of an alkali-stable fraction,and the alkali-stable fraction decreased markedly after thegermination. The alkali-stable carbohydrate gave, on acid hydrolysis,glucose alone. Starved conidia consumed glucose, maltose, , ß-limitdextrin, and also dextran as exogenous substrates for respiration.On the other hand, germ-tube elongation proved to be stimulatedby glucose, maltose, dextran and , ß-limit dextrinas well, but not by soluble starch, glycogen and glutinous ricestarch. Accordingly it follows that an alkali-stable carbohydrateincluding terminal glucopyranose residues combined through -l,6-glucosidelinkage seems to play an essential role in the production ofendogenous energy necessary for the germination of conidia inthis mold. Moreover, it is noteworthy that dextran was not usedas a nutrient for mycerial growth, whereas soluble starch wasfound to be an efficient carbon source. (Received June 5, 1960; )