Table 1 Strains, plasmids and primers.
Strain or plasmid or primer | Characteristicsa or sequencesb | Source, reference or function |
|---|---|---|
Bacterial strains | ||
 BL21 | For expression the recombinant plasmids | Invitrogen |
 χ7213 | thi-1 thr-1 leuB6 fhuA21 lacY1 glnV44 asdA4 recA1 RP4 2-Tc::Mu pir; Kmr | [48] |
 rSC0016 | ΔPcrp527::TT araCPBADcrp Δpmi-2426 ΔrelA199::araCPBADlacITT ΔsopB1686 ΔasdA33 | [29] |
 Streptococcus suis serotype 2 | Wild type, virulent, CVCC3928 | Lab stock |
 Streptococcus suis serotype 7 | Wild type, virulent, SH04805 | Provided by Professor Huochun Yao |
 Streptococcus suis serotype 9 | Wild type, virulent, GZ0565 | Provided by Professor Huochun Yao |
 Streptococcus suis serotype 1/2 | Wild type, virulent, 2651 | Provided by Professor Huochun Yao |
Plasmids | ||
 pYA3493 | Asd+; pBR ori, Ptrc promoter, β-lactamase signal sequence-based periplasmic secretion plasmid | [49] |
 pS-SaoA | pYA3493 with SaoA, Ptrc promoter | [29] |
 pS-Eno | pYA3493 with Eno, Ptrc promoter | This study |
 pS-SE | pYA3493 with a dual antigen expression cassettes consisting of SS2-SaoA and SS9-Eno, Ptrc promoter | This study |
 pET28a-SaoA | SS2-SaoA expression vector, T7 promoter; Kmr | [29] |
 pET28a-Eno | SS9-Eno expression vector, T7 promoter; Kmr | This study |
Primers | ||
 SS9-Eno-F | CGCTGCAGAGGACGCAAAAAATGAAAAAGACGGCTATCGC | The ORF of SS9-Eno |
 SS9-Eno-R | GCAAGCTTTTACTTTTTCAAGTTATAGAAT |  |
 SE-F | ATCCCGGGCAACCTGATGGGGGCCAGG | The ORF of SaoA-Eno |
 SE-R | GCAAGCTTTTACTTTTTCAAGTTATAGAAT |  |