Fig. 4

E. coli assists C. elegans in the uptake of micronutrients. Supplementation of folic acid to C. elegans is dependent on bacterial uptake of the breakdown product, PABA-glu, which is used as a precursor to generate tetrahydrofolate (THF). THFs were found to be more effectively absorbed than intact folic acid by C. elegans. B12 supplementation is dependent on the bacterial TonB-complex, indicating that a bacterial factor increases the bioavailability of B12. Iron supplementation is boosted by the bacterial siderophore, enterobactin, which associates with host mitochondria when bound to Fe³⁺ ions