TABLE 1.

Bacterial strains, plasmids, and primer sequences used for PCR

Strain or plasmidRelevant genotype and/or phenotypeaSource and/or reference
Strains
    E. coli TOP10F′F′ [lacIq Tn10(Tetr)] mcrA Δ(mrr-hsdRMS-mcrBC) φ80lacZΔM15 ΔlacX74 deoR recA1 araD139 Δ(ara-leu)7697 galU galK rpsL (Strr) endA1 nupGInvitrogen
    E. coli GM2163Dam/Dcm; F ara-14 leuB6 fhuA31 lacY1 tsx78 glnV44 galK2 galT22 mcrA dcm-6 hisG4 rfbD1 rpsL136(Strr) dam13::Tn9(Camr) xylA5 mtl-1 thi-1 mcrB1 hsdR2; CmrNew England BioLabs Inc.
    FAJ1905L. rhamnosus GG with chromosomal insertion of pMEC10 in the attB sequence of phage mv4; EryrThis study
    FAJ1906L. rhamnosus GG with chromosomal insertion of pFAJ1934 in the attB sequence of phage A2; EryrThis study
    L. casei ATCC 393Wild type; cheese isolateAmerican Type Culture Collection, Rockville, MD
    L. rhamnosus 1/6Wild type; cheese isolateValio Ltd.
    L. rhamnosus GGWild type; human isolateATCC 53103 (53)
Plasmids
    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; Eryr Ampr1
    pFAJ19342,634-bp PCR fragment (flanking EcoRI sites) carrying the nisRK genes of pMEC10 cloned into the EcoRI site of pEM40 downstream of the ery gene in the opposite orientation; Eryr AmprThis study
    pGK13Shuttle vector between E. coli and Lactococcus lactis; pWV01 replicon; Eryr Cmr27
    pLAB1301L. hilgardii pLAB1000 replicon; shuttle vector between E. coli and L. plantarum; Eryr Cmr21
    pMEC10Integration plasmid (attB located at the 3′ end of the tRNASer locus) containing int-attP cassette (of phage mv4) of pMC1 cloned into pNZ9500 (pUC19 derivative carrying a 2.7-kb chromosomal DNA fragment of L. lactis NZ9700 containing the 3′ end of nisP and nisRK); expression driven by ery read-through; Eryr42
    pMEC30L. hilgardii pLAB100 replicon; gfpuv cloned in expression vector containing the constitutive ldhL promoter from L. plantarum; Eryr Ampr15
    pMEC45L. lactis pSH71 replicon; pNZ8037 derivative with gfpuv cloned downstream of the nisA promoter from L. lactis NZ9800; Cmr15
    pNZ8008pNZ273 (pSH71 replicon) carrying the E. coli gusA reporter gene transcriptionally fused to the nisA promoter; Cmr28, N1Z0
    pRV85gfpuv cloned downstream of the L. sakei ldhL promoter in the replicative plasmid pG+host5; Eryr17
  • a gfpuv, synthetic GFP gene (with improved codon usage) that was subsequently subjected to recursive cycles of DNA shuffling, thereby selecting for bright fluorescence that could be observed under UV light.