. 2004 Oct;186(19):6492–6500. doi: 10.1128/JB.186.19.6492-6500.2004

TABLE 1.

Strains and plasmids used in the present study

Strain or plasmid	Characteristics and/or genotype	Source or reference
Strains
E. coli K-12
NM522	supE thi-1 Δ(lac-proAB) Δ(mcrB-hsdSM)5 (r_K⁻m_K⁻)/F′ proA proB lacI^q Δ(lacZ)M15	Amersham Biosciences
ML8166	NM522/pQWTA	This work
L. lactis
SK11	Wild type; Lac⁺ PrtP⁺ Opp⁺ Opt⁺	9
SKM6	SK11 derivative; Lac⁻ PrtP⁻ Opp⁻ Opt⁺	This work
Wg2	Wild type; Lac⁺ PrtP⁺ Opp⁺ Opt⁺	NIZO^a
MG1363	Plasmid-free derivative of NCDO 712; Lac⁻ PrtP⁻ Opp⁺ Opt⁻	12
IL1403	Plasmid-free derivative of IL594; Lac⁻ PrtP⁻ Opp⁻ Opt⁺	7
MLA	IL-1403 derivative with integration of pRMA in the optA gene; Lac⁻ PrtP⁻ Opp⁻ OptA⁻, Opt⁻, Ery^r	This work
MLS	IL-1403 derivative with integration of pRMS in the optS gene; Lac⁻ PrtP⁻ Opp⁻ OptS⁻ Opt⁺ Ery^r	This work
MLA521	MLA/pNZ521; Lac⁻ PrtP⁺ Opp⁻ OptA⁻ Opt⁻ Ery^r Cm^r	This work
MLS521	MLS/pNZ521; Lac⁻ PrtP⁺ Opp⁻ OptS⁻ Opt⁺ Ery^r Cm^r	This work
ILM521	IL-1403/pNZ521; Lac⁻ PrtP⁺ Opp⁻ Opt⁺ Cm^r	This work
Plasmids
pQE30	Expression vector of His₆-tagged proteins; Amp^r	QIAGEN S.A.
pQWTA	pQE30 derivative carrying the optA gene from L. lactis Wg2; OptA⁺ Amp^r	This work
pNZ521	pNZ122 derivative (pSH71 replicon) carrying the prtM and prtP genes from L. lactis SK11; PrtP⁺ Cm^r	9
pRV300	pBluescript SK(−) derivative; Amp^r Ery^r	25
pRMA	pRV300 derivative carrying a 500-bp PCR fragment of optA from L. lactis IL-1403; Ery^r	This work
pRMS	pRV300 derivative carrying a 500-bp PCR fragment of optS from L. lactis IL-1403, Ery^r	This work

NIZO, Netherland Dairy Research Institute (Ede, The Netherlands).