Figure 4
Metabolic rewiring upon O2 or nutrient deprivation. (a) Colorimetric determination of lactate in homogenates of whole larvae subjected or not to hypoxia for 16 h. Data represent the media +/− SD; p = 0.0078; Student’s T-test. n = 4 per group. (b) Laconic, Pyronic and OGsor FRET signal from wing imaginal discs from larvae exposed or not to hypoxia for 16 h before dissection and observation. Data represent the media +/− SD; p = 8.1723E-06 for Laconic and p = 6.878E-05 for Pyronic; Student’s T-test. n ≥ 20 per group. (c,d) Laconic FRET maps and quantification of wing discs, brains, midguts, fat bodies and salivary glands of 3rd instar larvae exposed or not to hypoxia. Note that the imaginal discs, brain and midgut from larvae exposed to hypoxia increase their lactate levels, while salivary glands and the fat body do not. Dotted lines mark the region in which the FRET signal was measured. Scale bar: 50 μm. Data represent the media +/− SD; p = 0.0009 for wing discs; p = 0.0011 for brain and p = 0.0494 for midgut; Student’s T-test; n ≥ 20 per group. (e,f) Time course of Laconic signal variation in a representative wing imaginal disc exposed or not to transient hypoxia. (g) Laconic, Pyronic and OGsor FRET signal of 3rd instar larvae wing imaginal discs incubated for 20 min in either Schneider medium or PBS prior to confocal analysis; data represent the media +/− SD; p = 2.5507E-06 for Laconic, p = 0.0037 for Pyronic and p = 4.1068E-05 for OGsor; Student’s T-test; n ≥ 20 per group. (h) Scheme of carbohydrate catabolism; variations of the metabolites monitored in this study upon hypoxia or starvation are indicated.
