A Modular Library of Small Molecule Signals Regulates Social Behaviors in Caenorhabditis elegans
Figure 6
Emerging model for a modular language of signaling molecules.
(A) icas#3 and ascr#3 are competing signals for N2 hermaphrodites. Mixtures of 120 fmol ascr#3 and 10 fmol icas#3 (Condition 1) attract worms to zone A, whereas larger amounts of a mixture of the same ratio (Condition 2; 12 pmol ascr#3 and 1 pmol icas#3) deter worms from zone A and instead attract to the periphery (zones B and C). In experiments with Condition 2, only one worm entered the treated zone A, whereas 31 worms entered control zone A (***p<0.0001, unpaired Student's t test with Welch's correction). (B) Synergistic blends of non-indole ascarosides induce dauer at nanomolar to micromolar concentrations and function as a male attractant at picomolar to nanomolar concentrations, whereas indole ascarosides icas#3 and icas#9 act as hermaphrodite attractants and aggregation signals at femtomolar to picomolar concentrations. (C) Modular assembly of C. elegans signaling molecules, based on building blocks derived from tryptophan (green), fatty acids (black), p-aminobenzoic acid (PABA, red), and carbohydrate metabolism (blue).