Figure 6: Mutual impact between C. elegans and E. coli and a model of the relationship mediated by ncRNAs between E. coli and C. elegans.

(a) Relatively more OxyS bacteria than K12 were left over a period of 5 days under the forage of C. elegans, even though OxyS grew slower than K12 bacteria on no-worm plates. Setup for the 5-day feeding experiment is shown at right. (b) Fewer worms on K12 than on NM6003 bacteria after a feeding period of 2 weeks. Setup for the experiment is shown at right. (c) The ratios of K12 to NM6003 bacteria on C. elegans forage plates were significantly higher than those ratios on no-worm control plates after a period of 2 weeks. (d) PCR of species-specific rDNA sequences showed coexistence of C. elegans and E. coli in three samples from the wild. There was E. coli but no C. elegans detected for samples 1 and 2; E. coli and C. elegans were co-detected in samples 3, 4 and 5; lane 6 was no-template control. (e) Potential B. mycoides OxyS sequence aligned with E. coli homologue, and C. elegans che-2-targeting site in E. coli OxyS is underlined (top). DsrA sequences from E. coli and B. mycoides are shown (middle), with labelling of F42G9.6-targeting site (dotted line), daf-2-targeting site (dashed line) and daf-15-targeting site (solid line). Alignments between B. mycoides DsrA and C. elegans daf-2/daf-15 mRNA are also shown (bottom). (f) Levels of daf-2 (left) and daf-15 mRNA (right) in C. elegans feeding on B. mycoides were lower than those on K12 E. coli. (g) A model of E. coli/C. elegans interaction mediated by E. coli ncRNAs. The Student's t-test was used to calculate the P values. *P value <0.05; **P value <0.01. All data are from three repeat experiments. Error bars represent s.e.m.