Not the result I was hoping for....

This is beta-galactosidase activity in cultures that have been transferred from LB (= rich medium) to M9 salts plus a tiny bit of casamino acids (starvation medium). Transfer was at time=0.

All cells carried the ppdA::lacZ fusion on the same plasmid. The black line is cells that are sxy+ and crp+. The blue line cells are sxy-, and the red line cells are crp-.

It's clear that beta-gal activity increased similarly in all three cultures. As seen for the cultures in rich medium (previous post), the crp- cells had slightly lower activity, while the sxy+ and sxy- cells had almost identical activity.

So I conclude that the treatments I've tried so far have not changed the Sxy-dependent activity of the ppdA promoter.