FIG. 2.

Decreasing the culture volume in vials that are the same size induces expression of CT. (A) Expression under air; (B) expression under nitrogen. In both panels volume is plotted on the x axis, and both the CT concentration (in micrograms per milliliter) and OD₆₃₀ are plotted on the left y axis. On the right y axis the [CT]/optical density (OD) ratio is plotted. The values above the open bars correspond to the OD₆₃₀s of cultures. The OD₆₃₀s were obtained with a microtiter plate reader (200 μl/well).