Table 1 Strains, plasmids and primers used in this study

Strains

 B. coagulans NL01

Undomesticated wild strain

Laboratory preservation

 B. coagulans ATCC 7050

Undomesticated wild strain

American Type Culture Collection

 B. coagulans XZL4

Undomesticated wild strain

Professor Ping Xu^a

 B. coagulans ATCC 7050 (ΔcelR)

celR deletion strain of B. coagulans ATCC 7050

This study

 L. lactis MG1363

Host for gene cloning

Laboratory preservation

 E. coli BL21(DE3)

Host for protein expression

Invitrogen

 E. coli BL21 (pET-celo1)

E. coli BL21(DE3) harboring the plasmid pET-celo1

This study

 E. coli BL21 (pET-celo2)

E. coli BL21(DE3) harboring the plasmid pET-celo2

This study

 E. coli BL21 (pETDuet-1)

E. coli BL21(DE3) harboring the plasmid pETDuet-1

This study

Plasmids

 pMH77

pSH71 replication containing temperature-sensitive vector, Cm^r

Professor Oscar P. Kuipers^b

 pMD-19T

Gene cloning vector, Amp^r

TaKaRa

 19T-celR1

pMD-19T containing the flanking regions of celR

This study

 pMH77-celR1

pMH77 containing the flanking regions of celR

This study

 pETDuet-1

Protein expression vector, Amp^r

Novagen

 pET-celo1

pETDuet-1 containing the CELO1 from B. coagulans NL01

This study

 pET-celo2

pETDuet-1 containing the CELO2 from B. coagulans NL01

This study

Primers

Sequences (5′ → 3′) and properties

 celR1up.f

GATCCGGAATTCCCACACAAAGGGAAATTACGTAAGCCAC (EcoRI)

This study

 celR1up.r

GTAAATGGCGGCGGCACTGAGCTCATGCCAACAACTCCCTTTTATCATTG

This study

 celR1down.f

CAATGATAAAAGGGAGTTGTTGGCATGAGCTCAGTGCCGCCGCCATTTAC

This study

 celR1down.r

CATCCGCTCGAGCAATATCATCCAGTTTCACCATATTCGG (XhoI)

This study

 celo1.f

AGATCTCTTGAACATAGAAGAAATCAGTTTTC (BglII)

This study

 celo1.r

GGTACCTTATTTTATACATGCCATTAACTCAT (KpnI)

This study

 celo2.f

GAGCTCGTTGATTTCGAATCGGCAAAAAC (SacI)

This study

 celo2.r

CTCGAGTTAAGCAATGCTATCCTTCGTCGT (XhoI)

This study