Table 3 Strains and plasmids used in this study

Strains

Streptococcus infantarius subsp. infantarius

CJ18

Wild type strain, suusac isolate

[2, 7, 31]

CJ18/pVE6007

CJ18 derivative carrying pVE6007, Cm^R

this study

CJ18ΔlacIIC

lacIIC::pLFB1005, lacIIC gene disruption derivative of CJ18, Em^R

this study

CJ18ΔlacZ

lacZ::pLFB1006, lacZ gene disruption derivative of CJ18, Em^R

this study

CJ18ΔlacS

lacS::pLFB1007, lacS gene disruption derivative of CJ18, Em^R

this study

Lactococcus lactis

LL302

RepA⁺ derivative of MG1363, host for pORI28

[51]

Plasmids

pORI28

Em^R, Ori⁺, RepA^-, pWV01 derivative, vector for chromosomal insertions in Gram-positive bacteria

[52]

pVE6007

Cm^R, thermosensitive derivative of pWV01, carrier plasmid for pORI28

[53]

pLFB1005

Em^R, pORI28 derivative containing a 939-bp internal fragment of lacIIC.

this study

pLFB1006

Em^R, pORI28 derivative containing an 1177-bp internal fragment of lacZ.

this study

pLFB1007

Em^R, pORI28 derivative containing a 900-bp internal fragment of lacS.

this study