(A) Cartoon of the FIRE response depicting the stress-induced redistribution of cytoplasmic esterase activity to a perinuclear region. The large rectangles contain cartoons of esterase activity (brown color) localization in two adjacent intestinal cells (rounded rectangles) with nuclei indicated by ovals labeled “N”. (B) Cytoplasmic esterase activity in intestinal cells of young adult hermaphrodites in the presence of ample bacterial food (Fed), 5-hours following food withdrawal (Fasted), and in eat-2(ad465) mutants (DR eat-2) or wildtype animals subjected to RNAi knockdown of let-363/TOR (let-363/TOR RNAi). Images are representative from 80 or more animals examined in at least 3 independent experiments. (C) DR induced by food source dilution also induced a FIRE response in wildtype adults. Young adult hermaphrodites, raised under bacteria-replete conditions, were fed with bacteria at indicated concentration for 5 hours and then analyzed. At high food concentrations (10¹⁰ and 10¹¹ cfu/mL) adult animals did not exhibit a FIRE response. At lower food concentrations, (<10⁹ cfu/mL), most animals exhibited a strong FIRE response. For each feeding condition, FIRE response was scored in 17-32 animals in a blinded fashion. Similar results were obtained in 2 additional experiments using a progressive nutrient stress regimen of diluted let-363/TOR RNAi (not shown).