FIGURE 1: A cartoon depiction of the feeding assay used in this study. The phenotypic outcome of each feeding condition is listed below each plate. (A) Heat-killed E. coli is not sufficient to support worm growth, nor is a trace amount of live E. coli, but when they are combined, worm growth is supported. (B) E. coli mutants deficient in enterobactin (Ent) synthesis did not support worm growth and reduced host iron. (C) Supplementation of Ent to Ent-deficient E. coli rescued worm growth and iron. (D) Feeding abundant Ent-deficient E. coli to worms resulted in a mild growth delay and low iron. The small circles represent trace, live E. coli (green: wild type, pink: Ent^–). The pink shape in (D) represents a lawn of abundant Ent^– E. coli.