FIG. 3.

Growth of an E. coli tonB mutant containing the V. cholerae fbpABC genes. E. coli tonB entF mutant strain ARM100 carrying either the vector plasmid pWKS30 or the fbp genes on the plasmid pFbp1 was spread at low density on LB agar containing either 1 μg EDDA per ml or 20 μM FeSO₄. Colony diameters were measured after 24 h at 37°C. The data are the mean diameters of 10 colonies from one representative experiment. The error bars indicate 1 standard deviation.