TABLE 3.

TetR_C58 and TetR_RP4 recognize noncognate tet operators

Strain	β-Galactosidase activitya		Growth on TC mediumb
	No TC	With TC	No ara	With ara
DH5α(pRK415K, pBetR)	NTc	NT	++	−
DH5α(pRK415K, pBAD22)	NT	NT	++	++
DH5α(pZLOP1)	2,311	2,211	NT	NT
DH5α(pZLOP1, pRK415K)	387	2,154	NT	NT

^aβ-Galactosidase activity is expressed as units per 10⁹ CFU as described in Materials and Methods. When needed, tetracycline (TC) was added to the culture at 10 μg/ml as an inducer. 

^bGrowth was assessed on LB medium supplemented with tetracycline at 5 and 10 μg/ml (TC medium) and with or without 0.4% arabinose (ara) added as an inducer. ++, good growth; −, no growth. 

^cNT, not tested.