Figure 5. Nematode preference to bacterial culture supernatants.

C. elegans prefers the spent cell-free culture supernatant of some Bcc strains to that of its prior E. coli diet. Cell-free supernatant from each Bcc strain was spotted opposite that from an E. coli OP50 culture. The fraction of nematodes traveling towards the Bcc supernatant within 1 h (up triangles) and then towards the E. coli supernatant by 3 h (down triangles) is shown. Within the first day, eggs from adult nematodes hatched and neonate migration at 24 h was observed (open circles). The error bars are SEM from three replicate assays.