TABLE 1.

Bacterial strains and plasmids used in this study

Strain or plasmidCharacteristicsSource or reference
S. enterica serovar Typhimurium strains
    ATCC 14028Wild typeAmerican Type Culture Collection
    ATCCrpoS ATCC 14028 ΔrpoS::Cm 21
    ATCCcrl ATCC 14028 Δcrl::Cm 21
    ATCCkatE-lacZ ATCC 14028 Tn5 22
    ATCCcrl katE-lacZ ATCC 14028 Δcrl::Cm, Tn5B21-2.4 22
    ATCCrpoS katE-lacZ ATCC 14028 ΔrpoS::Cm, Tn5B21-2.4 22
    ATCCdps ATCC 14028 Δdps::CmThis study
    ATCCdps-lacZ ATCC 14028 dps-lacZY This study
    ATCCcrl dps-lacZ ATCC 14028 Δcrl::Cm, dps-lacZY This study
    ATCCrpoS dps-lacZ ATCC 14028 ΔrpoS::Cm, dps-lacZY This study
Plasmids
    pACYC184Cmr Tetr, cloning vector 3
    pACYC184-KmCmr Kmr, identical to pACYC184 except that a 1.4-kb BamHI fragment carrying the Km cartridge from pUC4K is inserted into the BamHI site in the tet geneThis study
    pACcrl-1Tetr, pACYC184 with the promoterless crl gene cloned into the cat gene (crl is transcribed from the cat promoter) 21
    pACcrl-1-KmKmr, identical to pACcrl-1 except that a 1.4-kb BamHI fragment carrying the Km cartridge from pUC4K is inserted into the BamHI site in the tet geneThis study
    pSTK4Cmr, pACYC184::rpoS 15
    pUC4KCbr, Km resistance cartridgePharmacia