FIG. 1.

Measurement of C source repression of Pu with a lacZ reporter system. P. putida MAD2 cells bearing all of the elements required for Pu regulation assembled in the chromosome within a tellurite resistance mini-Tn5 transposon (sketched at the top) were grown overnight at 30°C in MM-CAA, diluted to an OD₆₀₀ of ∼0.05, and regrown under the same conditions in the presence or absence of 10 mM glucose. Note the identical growth rates in the two media. At the point indicated (OD₆₀₀, ∼1.2), samples were taken and their β-galactosidase (β-gal) levels were measured. Note the effect of glucose (G) on lacZ activity (plot to the right). U. Miller, Miller units.