Figure 1.

Recovery of enterocytes after infection entails retrograde transport from body reserves

(A) % of epithelium thickness categories from flies infected with SmDb11 resuspended in sucrose solution with 10% LB, PBS1x or a mix of essential and non-essential amino acids (chi-square, ∗∗∗∗ = p < 0.0001, comparisons between 16h and 3h from corresponding samples). Dissected midguts were qualitatively assigned after microscopic examination to either of three categories: thin epithelium (red), semi-thin epithelium (yellow) or thick epithelium (blue) (n = 24–30 per experimental condition, pooled from two to three independent experiments).

(B and C) (B) % epithelium thickness categories from flies infected for 3h with SmDb11 in PBS1x solution, and after transfer to sucrose with 10% LB, PBS1x or H2O (3h + 13h). For each condition, representative pictures of gut enterocytes are shown in (C). The measured epithelial thicknesses of midguts issued from an independent experiment are presented in Figure S1A.

(D and E) (D) % epithelium thickness categories from flies pre-fed in standard food or pre-starved for 24h after SmDb11 infection. Representative pictures of gut enterocytes are shown in (E).

(F) Quantification of free amino acids in the hemolymph of flies 3h and 6h after sucrose or SmDb11 infection. Bars represent the mean and the error bars display Standard Deviation of the data (one-way ANOVA, ∗∗ = p < 0.001, n = 3 × 20 hemolymphs).

(G) Flies were injected with 50 μM AHA and exposed to regular food, SmDb11 (infected), sucrose or water (starved). Midguts were dissected 6h later and fluorescence from the incorporated amino acid was assessed by staining with an alkyne probe and measured using ImageJ (One-way ANOVA; ∗ = p < 0.05; ∗∗∗∗ = p < 0.0001, n = 5–8). Stainings are shown in Figure S2A. The median bars represent the mean while the error bars display Standard Deviation of the data. (C, E) Green = Actin. Scale bars: 50μm (C) and 100μm (E).