Figure 4

TadD-dependent ND-G3PDH activity increases under lipid accumulation conditions in R. opacus PD630. A. Lipid accumulation increases during nitrogen limiting conditions. Lipids were extracted from wildtype R. opacus PD630 and the tadD mutant grown in either LB or minimal medium supplemented with either 1% (w/v) or 0.15% (w/v) ammonium sulfate and assayed using GC-FAMEs analysis. As predicted we observed an increase in total fatty acids when wildtype R. opacus PD630 was grown under nitrogen limiting conditions as compared to nitrogen replete conditions. Additionally, the tadD mutant demonstrated decreased lipid accumulation as compared to the wildtype, as shown above. B. ND-G3PDH activity in crude lysates from cultures grown under vegetative and lipid storage conditions. Cultures from above were lysed and the crude lysates assayed for ND-G3PDH activity. As with the total fatty acids, we observed a significant increase in the ND-G3PDH activity in cells grown under nitrogen limiting conditions as compared to those grown under nitrogen replete conditions. Furthermore, we observed significantly lower ND-G3PH activity in the tadD mutant.