Figure 4.—

sod-3 is expressed in the intestine of wild-type worms exposed to the pathogen E. faecalis in a daf-16-dependent manner. (A) Psod-3∷gfp or Psod-3∷gfp; daf-16;daf-2 (Libina et al. 2003) worms were exposed to E. coli, B. subtilis, or E. faecalis for 24 hr before photos were taken. Three worms under each condition are shown. For the top worm in each condition, the yellow arrows point to the heads of the worms and the white arrows flank the upper intestinal regions. (B) Quantification of the differences in intestinal Psod-3∷gfp expression of wild-type worms on E. coli, B. subtilis, and E. faecalis and of Psod-3∷gfp; daf-16;daf-2 worms on E. faecalis. The wild-type worms exposed to E. faecalis had significantly more GFP fluorescence compared to those on E. coli and B. subtilis and the daf-16;daf-2 worms on E. faecalis. Error bars in all experiments indicate the standard error. The significance of the observed differences was assessed by t-test analysis of the intestinal fluorescence measurements (see materials and methods). Differences with P < 0.05 were considered significant and marked with an asterisk.