A general method for isolation of Mu d1-8(Aprlac) operon fusions in Salmonella typhimurium LT2 from Tn10 insertion strains: chlC::Mu d1-8.

A general method was developed for the isolation of Salmonella typhimurium LT2 Mu d1-8 (Aprlac) operon fusions in a gene displacing a Tn10 insertion. Random Mu d1-8 fusion pools were prepared to grow phage P22 lysates which transduced chlC::Tn10 to AprTets on fusaric acid-ampicillin plates. Among these AprTets potential chlC::Mu d1-8 fusions, a simple spot test identified the fusions that were closely linked to the Tn10 insertion in chlC. Out of 68 AprTets isolates 7 chlC::Mu d1-8 fusions with a nitrate-induced Lac+ phenotype were obtained. When oxrA::Tn10 was transduced into these chlC::Mu d1-8 fusions, they became Lac- even in the presence of nitrate, confirming that they were chlC::Mu d1-8 fusions.