Table 1.

Bacterial strains and plasmids used

Bacterial strain or plasmidDescriptionReference or source
E. coliDH5αF endA1 hsdr 17 (rK mK +) thi-1 λ recA1 gyrA96 relA1 φ80dlacZΔM15 16
S. flexneri 2a
 YSH6000Wild-typeS. flexneri 2a Japanese isolate, AprStrepr TetrCmr 39
 YSH6200Derivative of YSH6000 cured of the 230-kb virulence plasmid 33
 YSH6000TSpontaneous Aps StrepsTets Cms variant of YSH6000 24
 SBA1336Derivative of YSH6000T harboring a Tcr cassette withinshe 32
 SBA1351Derivative of YSH6000T harboring a Kmr cassette withinsigA This study
 SBA1341Tcsderivative of SBA1336 exhibiting a 51-kb chromosomal deletion 32
 SBA1356Derivative of SBA1336 harboring an Ω cassette within sepA This study
 SBA1361Derivative of SBA1341 harboring pSBA479This study
 SBA1413Derivative of SBA1351 harboring pSBA572This study
Plasmids
 pPBA1100pUC18-based high-copy-number vector, Kmr ΔlacZ 20
 pWSK29pSC101-based low-copy-number vector, AprΔlacZ 46
 pWSK30pSC101-based low-copy-number vector, AprΔlacZ 46
 pWSK130pSC101-based low-copy-number vector, KmrΔlacZ 46
 pCACTUSpSC101-based low-copy-number vector withsacB, Cmr 43
 pBzHybrid of pBluescriptSK+ and pZero 1.1, ccdBgene replaces ΔlacZS. Doughty, Monash University
 pUC4KSource of Kmr gene from Tn903, Apr Kmr 44
 pPBA11802.0-kb Ω fragment consisting of the Strepr/Specr gene of the R100.1 plasmid cloned into pUC19 29; M. Hunt, Monash University
 pSBA41519.9-kb SalI fragment of SBA1336 bearing the 3′ truncated she gene with an insertedtetAR(B) cassette cloned into BamHI site of pWSK29, Apr Tcr 32
 pSBA4323.6-kb EcoRI fragment of pSBA415 cloned into EcoRI site of pWSK130, Kmr N. Ngoc, Monash University
 pSBA4795.4-kbSalI/HindIII fragment of pSBA415 cloned intoSalI/HindIII sites of pPBA1100, Kmr This study
 pSBA4931.2-kb AccI fragment carrying a Kmr of pUC4K cloned in the uniqueClaI site in pSBA479This study
 pSBA5016.7-kb Expand PCR product containing the insertionally disruptedsigA gene cloned in pCACTUS T-tailed SmaI siteThis study
 pSBA5443.3-kb PCR product containingsepA cloned into BamHI site of pBzThis study
 pSBA5492.0-kb HindIII Ω fragment cloned into unique HindIII site in pSBA544This study
 pSBA5505.3-kb BamHI fragment (sepA-Ω) of pSBA549 cloned in the unique BamHI site in pCACTUSThis study
 pSBA5725.4-kbSalI/HindIII fragment of pSBA479 cloned into the SalI/HindIII site in pWSK30This study