Table 1.

Bacterial strains and plasmids used in this study

Strain or plasmidRelevant characteristicsSource or reference
V. cholerae
  AS207O139 Calcutta strain 20
  O395O1 classical strain 15
  E79461978 El Tor clinical isolate from Bahrain 13
  2740-80U.S. Gulf Coast isolate, attRS +, CTXφ 16
E. coliCC118ΔlacX74 recA1 phoAF 12
 pHK101pCB192 derivative,rstA c l a s s-lacZreporter 9
 pHK102pCB192 derivative,rstA ET-lacZreporter 9
 pBD40pCB192 derivative,rstA c a l c-lacZ reporterThis study
 pHK2pBAD33 derivative, ARA-inducible RstRc l a s s 9
 pHK1pBAD33 derivative, ARA-inducible RstRET 9
 pBD87pBAD33 derivative, ARA-inducible RstRc a l c This study
 pCTXET-KnReplicative form of CTXET-Knφ, previously called CTX-Knφ 22
 pCTXET-Ap XbaI fragment of pCTXET-Kn inserted into pGP704This study
 pCTXc a l c-KnReplicative form of CTXc a l c-Knφ prophage from AS207 CTXc a l c::Kn, contains El Tor rather than Calcutta ig-1 region of CTXφThis study
 pCTXc a l c-Ap XbaI fragment of pCTXc a l c-Kn inserted into pGP704This study
 pCB192β-Galactosidase reporter plasmid, Apr 18
 pBAD33ARA-inducible promoter vector, Cmr 7
 pGP704 oriR6K mobRP4 suicide vector, Apr 17
 pCACTUSAllele-exchange vector, Temperature-sensitive ori,sacB +, Cmr Chris Clark
 pHK260pCACTUS derivative containing theSphI/BglII fragment of pCTXET-KnThis study