Glucose 13C-4 was always the most discriminated against and the
DI of glucose 13C-2 was nearly always significantly higher. Glucose
13C-1 and 13C-6 showed a slight preferential degradation; their DI
lay mostly around 0.5. The only exceptions to this pattern of glucose
incorporation were the fungal PLFAs e there was no significant
difference between discrimination against the four positions. For
ribose, we observed a clear pattern on day 3: preferential incorporation
of ribose 13C-5, with a significantly lower DI for 13C-1. For
both glucose and ribose, the overall divergence in all groups was
lower on day 10 than on day 3.