Table 1.

Laboratory strains and plasmids

Strain or plasmidRelevant characteristic(s)Reference(s)
Strains
 AG100Wild-typeE. coli K-12 strain 16
 AG102 marR1 mutant of AG100, selected on tetracycline 10, 16
 ASS121SPC105 bearing a marOII ::lacZtranscriptional fusion and a 1.24-kbp BspHImarRAB operon-specific deletion; Ampr 11, 40
 GC4468Wild-typeE. coli K-12 strain (F Δlac-4169 rpsL) 8
 DJ901GC4468,soxRSΔ901::Tn10Kmr 18
 JTG1078GC4468, soxR105 zjc-2204::Tn10Kmr 17
Plasmids
 pMAK-TU1&TU2Derivative of pMAK705; temperature-sensitive cloning vector with a 2.4-kb insertion containingmarRAB and marC (bp 163 to 2592) and with amarR5 mutation; low copy number; Cmlr 43
 pSPOKDerivative of pSPORT1 (Gibco/BRL) in which the bla gene was replaced with a kanamycin resistance gene; used for cloning marOR from clinical strains; high copy number; IPTG inducible 25
 pSXSDerivative of pSE380 (Invitrogen, San Diego, Calif.) containing the soxS gene on a 432 bp-fragment; high copy number; IPTG inducible 2