Fig. 1.

Response of wild-type and mutant Salmonella strains to chemoeffectors in soft-agar swim plates. (A) Top row: WT (14028), BC only* (JW20), B only* (MB2), C only* (MB1) C / Aer only* (SM576), Δ7T* (SM162) and BC only (MB203) strains were inoculated at the center of LB swim plates and incubated at 37°C for 7 h, when the wild-type had just reached the edge. * indicates that McpA and Tip are still present in the strains. Second row: Plates shown in the top row were incubated for an additional 16 h at room temperature, by which time the BC only* strains colonized half the plate. (B) The BC only* strain was inoculated in minimal-glycerol swim media containing either the commercial MEM essential amino acid mix or the indicated nutrient mixes and incubated at 37°C for 22 h (see Experimental Procedures). (C) BC only* and ΔBC strains (SM542) were inoculated in minimal-glucose swim media containing the essential MEM mix or indicated amino acids and incubated at 37°C for 22 h. The MEM mixes in this experiment were reconstructed to reflect the composition of the commercial mix.