FIG. 1.

Concentration response curves for chemotactic responses to pyrimidines by E. coli RP437 (wild type). Cells were grown at 30°C in H1 minimal salts medium containing 25 mM glycerol, the required amino acids, and thiamine. Assays were performed at 30°C with each pyrimidine up to its limit of solubility. Results are the averages of at least 10 capillaries from at least three independent experiments; error bars indicate standard errors. Data are not corrected for background accumulation in capillaries containing buffer only (∼5 × 10³ cells).