Fig. 3.

Homogeneous attractants slow and repellents increase bacterial soft agar migration. (a, b) Colony expansion of H. pylori SS1 (a) or G27m (b) in soft agar media composed of 1× tryptone, 2× tryptone, 3× tryptone, 1× Brucella broth (BB) or 2× BB, all with additional 2.5 % FBS. Data shown are representative of three or more replicates. (c) H. pylori grows more robustly in 2× or 3× tryptone/FBS media than in 1× tryptone. (d) E. coli in tryptone soft agar supplemented with 1–10 mM serine or 0.025–0.3 mM NiSO₄. Migration distances are the means of two to four biological replicates, which included seven to eight technical replicates each. Error bars, sem. Distances and errors were normalized to the wild-type RP437 no-addition sample (2.2 cm); RP8611 yielded 0.01 cm at the same time point. *P<0.05 using Student’s t test on the non-normalized data. (e) Appearance of E. coli soft agar plates supplemented with 10 mM serine as compared with no addition.