Figure 1.
Experimental design and chemical analysis workflow.
(1) pre-conditioning (entrainment) of the culture stock (adaptation to the 12/12-h (light/dark) cycle); (2) incubation of female fruit flies with 13C6-glucose solution; (3) dissection of the anesthetized flies; (4a/4b) preparation of individual eggs for mass spectrometric analysis; (5) mass spectrometry, and (6) data analysis.
Figure 2.
Isotopic labeling of ATP and UDP-glucose in single eggs.
(A) MALDI mass spectra obtained from fruit flies following 1, 6, and 19 days of incubation with the 13C6-glucose solution. (B) Reaction scheme of labeling glucose moiety in UDP-glucose with 13C6-glucose.
Figure 3.
Progressive incorporation of the 13C-label to UDP-glucose in fruit fly eggs.
The data points were fitted with a sigmoid function: y = 1.013·(1/(1+e(−0.135x+1.792))). During this experiment, the flies were incubated with 13C6-glucose and illuminated with white light (∼ 4000 lux). Note that the sampling intervals (as projected onto the x-axis) are coincidentally not constant.
Figure 4.
Influence of temperature (21 vs. 28°C) and illumination (dark vs. light) on the labeling of glucose moiety in UDP-glucose molecules extracted from individual eggs.
Female flies were incubated with 13C6-glucose solution during 24 h. The default conditions were: white light on, ∼4000 lux (in the study involving the change of temperature); temperature, 28°C (in the study involving the change of illumination).
Figure 5.
Histograms showing the distributions of labeling levels within the eggs obtained from the fruit flies incubated with 13C6-glucose (during 12 h) at different illumination conditions and at different times during the day/night cycle.
ML – flies incubated during day (starting from the morning) at light; MD – flies incubated during day (starting from the morning) at dark; EL – flies incubated during night (starting from the evening) at light; ED – flies incubated during night (starting from the evening) at dark.
Table 1.
Notation used in this report.
Figure 6.
Histograms showing differences in the labeling of eggs among flies from the same treatment.
Flies incubated during night (starting from the evening) at dark (ED): arbitrarily selected examples of five single-fly histograms, ordered according to the increasing level of labeling (Fly #1 to #5: top to bottom). All single-fly histograms from this experimental variant are displayed in Figure S9.