Figure 5. Trehalose metabolism affects haemolymph water volume and desiccation tolerance.

(A) Tps1 and Treh mutations affect the volume of haemolymph at the wandering stage. The weights of haemolymph in the indicated genotypes were measured and normalized according to wet weight. Heterozygous mutants are included to validate the accuracy of the measurements. (B) Relative proportions of haemolymph volume, dry weight, and the predicted water content in tissues are shown. (C) Tps1 mutants exhibited no change in haemolymph osmolarity. (D) Protein concentrations in the haemolymph were analyzed in late third instar larvae of the indicated genotypes. (E) Desiccation reduced water contents in early third instar larvae. Relative proportions of water content and dry weight were normalized to the values of wet weight before desiccation. (F) Survival rates after desiccation and rehydration. Early third instar larvae were used to test 3 hr or 6 hr of desiccation followed by rehydration. (G) Survival rates under sucrose or water-only dietary conditions. Early third instar larvae were kept under each condition for 12 hours. Statistical significance is determined by two-tailed Student’s t-test (P < 0.01). All the values are means and SD (n > 6 [A–D] or n > 3 [E–G]).