Table 1. Strains and plasmids used in this study.

Strain or plasmid	Description	Source
Strains
Escherichia coli M182	Δlac galK galU strA	[39]
Escherichia coli M182Δcrp		[39]
Plasmids
pRW50	Broad-host-range lac fusion vector for cloning promoters on EcoRI–HindIII fragments: contains the RK2 origin of replication and encodes TcR.	[40]
pSR	pBR322-derived plasmid containing an EcoRI–HindIII fragment upstream of the λoop transcription terminator	[17]
pRW225	pRW50-derived plasmid in which the ribosome binding site upstream of lacZ has been deleted.	[23]
pDCRP	crp gene preceding its native promoter (located on EcoRI-SalI flanked fragment). pBR322 derived. Encodes AmpR. ColE1 origin.	[41]