## Figure 4 .
Direct addition of iron, but not spent medium, stimulates growth on glucose for citrate-dependent
evolved lineages. The ratio and error for growth parameters was calculated by fitting a log-linear
model with the strain:media interaction terms and block as the dependent variables.
Both the relative (A) growth rate and (B) yield of the three strains from populations stimulated by sodium citrate (black
circles) were at least partially enhanced by direct addition of 10 μM Fe (II) (as
ammonium iron sulfate, red squares). In contrast, growth in spent media re-supplemented
with glucose (blue triangles) did not stimulate growth. Values represent the mean
and 95% confidence intervals for the ratio of growth of that strain on glucose with
the supplement to growth without.
Leiby |