MODULATION OF SPORULATION AND METABOLIC FLUXES IN SACCHAROMYCES-CEREVISIAE BY 2-DEOXY GLUCOSE

Quantitative studies of metabolic fluxes during Saccharomyces cerevisi ae sporulation on acetate in the presence of the glucose analog, 2-deo xy glucose (2dG) are reported. We have studied the inhibition of sporu lation and associated catabolic or anabolic fluxes by 2dG. Sporulation frequencies decreased from 50% to 2% asci per cell at 2dG concentrati ons in the range of 0.03 to 0.30 g l(-1), respectively. Under the same conditions, the acetate consumption flux was inhibited up to 60% and the glyoxylate cycle and gluconeogenic fluxes decreased from 0.7 and 0 .3 mmol h(-1) g(-1) dw, respectively, to negligible values. We observe d a linear correlation of the acetate consumption rate with the sporul ation frequency by varying the 2dG concentration. The linear correlati on was also verified between the frequency of sporulation and the flux es through glyoxylate cycle and gluconeogenic pathways. In addition, t he same association of inhibition of sporulation and metabolic fluxes was found in other S. cerevisiae strains displaying different potentia ls of sporulation. The results presented suggest that inhibition of sp orulation in the presence of the glucose analog may be attributed, at least in part, to the inhibition of anabolic fluxes and might be assoc iated with catabolite repression.