Table 1. Bacterial strains, plasmids and oligonucleotides used in this study.
| Name | Relevant feature | Reference |
| Strains | ||
| E. coli DH5α | Cloning host | Invitrogen |
| E. coli DH5α pBAD_LuxSNCC | AmpR, host for arabinose-inducible expression of luxS of B. longum NCC2705 | this study |
| E. coli DH5α pBAD_LuxSS17 | AmpR, host for arabinose-inducible expression of luxS of B. bifidum S17 | this study |
| E. coli DH5α pBAD_LuxSE18 | AmpR, host for arabinose-inducible expression of luxS of B. longum E18 | this study |
| E. coli DH5α pBAD_LuxSVh | AmpR, host for arabinose-inducible expression of luxS of V. harveyi BB170 | this study |
| B. longum NCC2705 | Sequenced type strain | [33] |
| B. longum NCC2705 pMgap | SpecR, pMgap, empty vector control | this study |
| B. longum NCC2705 pMgap_LuxSNCC | SpecR, vector for constitutive, homologous expression of LuxS of B. longum NCC2705 | |
| B. bifidum S17 | Faecal isolate of a breast-fed infant, genome sequenced | [34] |
| B. longum E18 | Faecal isolate of an adult, genome sequenced | [35] |
| V. harveyi BB170 | AI-2 reporter strain, luxN::Tn5 | [36] |
| Plasmids | ||
| pBAD | AmpR, vector for arabinose-inducible expression in E. coli | this study |
| pBAD_LuxSE18 | AmpR, pBAD-based vector for arabinose-inducible expression of luxS of B. longum E18 | this study |
| pBAD_LuxSNCC | AmpR, pBAD-based vector for arabinose-inducible expression of luxS of B. longum NCC2705 | this study |
| pBAD_LuxSS17 | AmpR, pBAD-based vector for arabinose-inducible expression of luxS of B. bifidum S17 | this study |
| pBAD_LuxSVh | AmpR, pBAD-based vector for arabinose-inducible expression of luxS of V. harveyi BB170 | this study |
| pMgap | SpecR, vector for constitutive expression of proteins in bifidobacteria driven by the gap promoter (Pgap) of B. bifidum S17 | this study |
| pMgap_LuxSNCC | SpecR, vector for Pgap-driven expression of luxS of B. longum NCC2705 | this study |
| Oligonucleotide | Sequence (5′ → 3′) a | Restriction Site |
| VH1 | GG ACTAGT ATGCCTTTATTAGACAGC | SpeI |
| VH2 | CC ATCGAT TTAGTCGATGCGTAGCTC | ClaI |
| LF | GG ACTAGT ATGGCAGAAGAAACGGC | SpeI |
| LR | CC ATCGAT TCAGACGACCTTGCGCTC | ClaI |
| SLF | GG ACTAGT ATGGCAGAAGAAAAGCCG | SpeI |
| SLR | CC ATCGAT TCAGACGACCTTGCGCTC | ClaI |
| eLF | GGC CTCGAG ATGGCAGAAGAAAAGCCG | XhoI |
| eLR | CCC AAGCTT TCAGACGACCTTGCGCTC | HindIII |
a
recognition sequences for restriction enzymes are underlined.