Fig. 2

Modeling acute exercise using OMCs. A Schematic showing the experimental set up and frequency of OMCs used for modeling of acute exercise in Drosophila larvae. L1 and L3 correspond to first and third larval instar stages, respectively, and ATR is all-trans retinal. B Anti-Glycogen antibody staining of larval muscles before and after 2 hours of acute muscle exercise. Control animals do not show a strong change in the levels of glycogen during the 2 hours of light stimulation. Experimental animals, however, show strong reduction in glycogen staining levels, suggesting a depletion of muscle glycogen reserves. Scale bars = 50 μm. C Quantification showing average size of the glycogen particles identified using the anti-glycogen antibody. **** represents a p-value ≤0.0001 by Student’s t-test. D BODIPY staining of larval fat body cells showing the effect of acute exercise on lipid droplet size. While control animals do not show any change in response to 2 hours of light stimulation, experimental larvae show a significant reduction in the size of lipid droplets in their fat body. The mean area of the lipid droplets at 0 and 2 hours of light stimulation was quantified for both genotypes and is presented in the adjacent graph. N = 7 biological replicates and two-way ANOVA followed by post-hoc test was used for calculating significance. ** denotes p ≤ 0.01. Scale bars = 20 μm. E BODIPY staining of larval fat oenocytes showing the effect of acute exercise after 2 hours on lipid accumulation in the oenocytes. F Quantification of oenocyte BODIPY staining. Experimental animals show a significant increase in neutral lipid staining in response to 2 hours of light stimulation, but control animals do not. 8–14 oenocyte clusters from 4 independent animals (N = 4) were imaged for the analysis. N = 4, Two-way ANOVA followed by post-hoc test was used for calculating significance. **** denotes p ≤ 0.0001, *** denotes p ≤ 0.001, ** denotes p ≤ 0.01, and ns denotes 'not significant'. G Quantification of the mRNA expression levels of Drosophila IL6 orthologs, upd1, upd2 and upd3, in the body wall muscles of control and experimental animals subjected to 2 hours of light stimulation. upd2 and upd3 expression increased significantly only in experimental animals after 2 hours of light stimulation. upd2 showed ~ 30 fold increase in expression in response to acute exercise. N = 4 biological replicates