Table 1.

Bacterial strains and plasmids used in this study

Strain or plasmid	Description	Reference
V. cholerae O1 E1Tor Inaba	Strain A1552, Wild type	[13]
V. cholerae ΔtoxR	Transcriptional activator deletion mutant of Strain A1552	This study
E. coli DH5α	Φ80dlacZΔM15 recA1gyrA96 thi-1 hsdR17 (rk- mk+) supE44	[14]
Sm10λpir	relA1deoRΔ(lacZYA-argF)U169	[15]
	thi-1, thr, leu, tonA, lacY, supE,
	recA::Rp4-2-Tc::Mu,KmR,(λpir)
Plasmid Puc 18	ApR lacZaovi colE1	[16]
Plasmid PCVD442	oriR6K mobRP4 sacB Apr	this study