TABLE 1.

Bacterial strains and plasmids used in this study

Strain or plasmidRelevant genotype or descriptionReference or source
Strains
    E. coli DH5αF φ80dlacZΔM15Δ (lacZYA-argF)U169 deoR recA1 endA1 hsdR17(rK mK) supE44 λ thi-1 girA96 relA1Gibco-BRL
    L. rhamnosus GG
        Wild typeHuman isolateATCC 53103 (48)
        CMPG5412luxS knockout mutant of L. rhamnosus GG; luxS::tet(M); reduced growth capacityThis study
        CMPG5339CMPG5412 complemented by integration of pCMPG5339This study
        CMPG5912CMPG5412 complemented by integration of pCMPG5912This study
        CMPG5413luxS knockout mutant of L. rhamnosus GG; luxS::tet(M); putative suppressor mutant; wild-type growth capacity; no biofilm formationThis study
    V. harveyi
        BB170luxN::Tn53
        BB152luxM::Tn5 (AI-1 AI-2+)4
Plasmids
    pCRII-TOPOCloning vector; ampicillin and kanamycin resistanceInvitrogen
    pFAJ5301Cloning vector; pUC18 derivative; erythromycin resistanceUnpublished results
    pLAB1301E. coli-Lactobacillus shuttle vector; ampicillin and erythromycin resistance29
    pMD5057Tetracycline resistance plasmid from L. plantarum 505710
    pEM40pUC19E-derived integration vector (attB located at the 3′ end of the tRNALeu locus) containing a 1.6-kb int-attP cassette of phage A2; ampicillin and erythromycin resistance2
    pCMPG5332pFAJ5301-derived suicide vector to knock out the luxSLGG gene through insertion of the tet(M) gene from pMD5057This study
    pCMPG5339pEM40-derived integration vector containing the luxSLGG gene and its putative promoter P2This study
    pCMPG5912pEM40-derived integration vector containing the putative yxjH-luxS operon of L. rhamnosus GG, its putative promoter P1, and the putative methionine-specific T box in the 5′ UTRThis study