Bicarbonate-induced synthesis of polysaccharide during morphogenesis by synchronous, single-generations of blastocladiella emersonii

Summary

Relative to the formation of an ordinary colorless plant of Blastocladiella emersonii (which does not require bicarbonate for its formation), the bicarbonate-induced genesis of a resistant-sporangial plant (R.S.) is associated with: (a), a two-fold increase in the rate of exponential, net synthesis of an endogenous, apparently highly branched, glycogen-like polysaccharide; and (b), a three-fold increase in the total pool of this polysaccharide built up within the plant.

The polysaccharide accumulates during the early development of an R. S. plant in synchronous, single-generation culture when glucose is being consumed rapidly from the medium without detectable production of lactic acid.

The accumulated polysaccharide pool disappears again during the “maturation” period of a resistant-sporangial plant, when glucose is no longer being consumed from the medium. During this time, (a), approximately one mole of lactic acid is liberated per mole of polysaccharideglucose consumed; and (b), the specific activity of glucose-6-phosphate dehydrogenase rises sharply. These observations are consistent with the possibility that the final “maturation” of the resistant sporangium is associated with an increase in glucose metabolism via the hexose monophosphate shunt.