Influence of Nitrogen Sources on Glycogen Metabolism in Saccharomyces carlsbergensis

Abstract

Storage of glycogen in yeast (Saccharomyces carlsbergensis) cells was strongly suppressed by the presence of nitrogen sources. Peptone initiated glycogen breakdown within minutes. This effect could not be duplicated with ammonium ions alone nor with single amino acids or mixtures of a few amino acids, but it could be duplicated by the addition of all the amino acids in the molar ratios found in casein. If fewer amino acids were supplied, glycogen was initially synthesized but then depleted after 30-60 min at 28 "C, the time being shorter for more easily utilized amino acids. In the presence of glucose, dinitrophenol ( M) slowed down or inhibited glycogen synthesis, but it did not initiate glycogen breakdown in the absence of glucose. Energy charge and the concentrations of adenylates and UDP-glucose were not significantly different in the presence and absence of peptone; pyruvate accumulated under the former condition. No turnover of glycogen was observed during glycogen synthesis, pointing to an effective regulation of glycogen metabolism via an unknown mechanism.

Reserve carbohydrates metabolism in the yeast Saccharomyces cerevisiae

“…Conversely, resuspension of starved cells or stationary phase cells in a growth medium with a fermentable carbon source elicits a mobilization of glycogen and trehalose which is associated with a sustained activation of neutral trehalase and glycogen phosphorylase, and an inactivation of glycogen synthase [2,3,22,158,159]. These changes are likely brought about by the transient glucose-induced cAMP-dependent activation of PKA, followed by a sustained nutrient stimulation of PKA activity to high level by a still poorly characterized cAMP-independent pathway (referred as the fermentable growth medium or FGM pathway, reviewed in [160]).…”

Reserve carbohydrates metabolism in the yeastSaccharomyces cerevisiae

“…Conversely, resuspension of starved cells or stationary phase cells in a growth medium with a fermentable carbon source elicits a mobilization of glycogen and trehalose which is associated with a sustained activation of neutral trehalase and glycogen phosphorylase, and an inactivation of glycogen synthase [2,3,22,158,159]. These changes are likely brought about by the transient glucose‐induced cAMP‐dependent activation of PKA, followed by a sustained nutrient stimulation of PKA activity to high level by a still poorly characterized cAMP‐independent pathway (referred as the fermentable growth medium or FGM pathway, reviewed in [160]).…”

Ca(2+)-induced sporulation in the fungus Achlya : the biological roles of [Beta]-(1->3)-glucans and key enzymes /

“…Therefore, sporulation may provide a convenient system for the investigation of carbohydrate metabolism, the roles of the reserve materials and the associated hydrolytic enzymes. In yeast the extraspore reserve carbohydrates synthesized early in development are completely degraded prior to spore formation, suggesting they have a role as a source of energy and carbon for spore formation (Rothman and Cabib, 1969;Becker et al, 1982;Katohda et al, 1988;Rua et al, 1993 consisting of a neutral form (20%) and a phosphorylated form (80%) (Lee et al, 1996). Under conditions of starvation ( no glucose in the culture medium ) or Ca -induced sporulation, the myceUal glucans decrease dramatically, and their total phosphate content decreases 49% (Lee and Mullins, 1994).…”