FIG. 2.

Glucose circumvents the problem caused by the presence of propionate in the medium. Growth curves were determined in NCE medium. Succinate and propionate were each at 30 mM. A prpC⁺ strain (closed triangles) grew on succinate plus propionate medium, while a prpC strain (closed diamonds) did not. However, the addition of glucose (0.3 mM) to the medium allowed the prpC strain to grow (open diamonds). The prpC strain did not grow when 0.3 mM glucose was the sole carbon and energy source (closed circles).