Figure 6. YfiN-mediated SCVs resist nematode predation and phagocytosis.

A) SCV resistance to nematode predation. Panel 1 shows C. elegans incubated with PA01 as a food source for 72 hours. Panels 2 to 5 show the corresponding experiments with ΔyfiR (2), ΔyfiR pelG::Tn (3), ΔyfiR ΔpslAB (4) and ΔyfiR pelG::Tn ΔpslAB (5), respectively. Eggs and mature adults were seen with PA01 (1) and the double exopolysaccharide mutant (5) only. Worms and larvae are indicated with black arrows. Insets to panels 1 and 2 show nematodes incubated for three hours with GFP-labeled PA01 or ΔyfiR, respectively. B) Macrophage absorption assay. Values shown are the fraction of J774 macrophages whose lysosomes co-localize with at least one bacterium. White bars show PA01 background strains, dark grey bars denote a ΔyfiR background. C) Surface attachment patterns of ΔyfiR exopolysaccharide mutants. Panels show attachment to polystyrene of GFP-labeled bacteria (green) following three hours growth at 37°C. J774 macrophages are stained with DAPI (blue) and Lysotracker (red).