Impact of Flo11p on predator deterrence in yeast colonies. (A) Suspensions of GFP-labeled WT cells (PC6733) grown for 16 hr in synthetic or YEPD media (16 hr) were examined. Merged fluorescent and brightfield images of heads of mounted C. elegans showing fluorescent S. cerevisiae inside the animal pharynx after 45 min feeding (merged). Fluorescent images of individual S. cerevisiae inside the animal pharynx (inset = GFP). (B) Bar graph showing difference in average number of S. cerevisiae cells in C. elegans pharynx between YEPD- and synthetic-grown suspensions. Error bars are SE. * P < 0.05. (C) Selected images from videos showing WT C. elegans entering WT or flo11Δ yeast colonies. A set of representative videos are available in the supplement (Videos S8–S15). (D) Dot plot showing the time required for worms to enter the indicated colonies. WT (N2) or glr-1(lof) C. elegans worms were placed on plates containing WT or flo11Δ yeast, or the E. coli food strain OP50. (E) Stacked bar graphs comparing C. elegans forward movement to stalls and/or reversals in the indicated yeast or E. coli colonies. (F) Three-day-old colonies of WT (PC538) and flo11Δ (PC1029) cells expressing-plasmid borne GFP (PC2560). C. elegans transferred into the colony for 45 min before mounting. Merged fluorescent images of head and tail regions of C. elegans showing fluorescent S. cerevisiae inside the animal (merged). Fluorescent images of individual S. cerevisiae inside the animal (inset = GFP). (G) Bar graph showing difference in average number of S. cerevisiae cells in the C. elegans pharynx between WT and flo11Δ colonies. Error bars are SE. * P < 0.05. WT, wild-type; YEPD, yeast extract, peptone, and dextrose.