Table I. Bacterial strains and plasmids used in this study
Bacterial StrainDescriptionReference
Y. pseudotuberculosis
 YPIII/pIB1Serotype O:3, wild type(31)
 YPIII/pIB1 ailail::kan, KmR, derivative of YPIII/pIB1(15)
 YPIIIpYV-cured derivative of YPIII/pIB1(31)
 YPIII ailail::kan, KmR, pYV-cured derivative of YPIII/pIB1(15)
E. coli BL21(DE3)Standard laboratory strainInvitrogen, Carlsbad, CA
Plasmids
 pBR322Standard cloning vectorPromega, Madison, WI
 pAY43pBR322 ail+ from strain YPIII(4)