A general method for isolation of Mu d 1-8(Ap^rlac) operon fusions in Salmonella typhimurium LT2 from Tn 10 insertion strains: chlC::Mu d 1-8

A general method was developed for the isolation of Salmonella thyphimurium LT2 Mu d1-8 (Ap^rlac) operon fusions in a gene displacing a Tn 10 insertion. Random Mu d1-8 fusion pools were prepared to grow phage P22 lysates which transduced chlC::Tn 10 to Ap^rTet^s on fusaric acidampicillin plates. Among these Ap^rTet^s potential chlC::Mu d1-8 fusions, a simple spot test identified the fusions that were closely linked to the Tn 10 insertion in chlC. Out of 68 Ap^rTet^s isolates 7 chlC::Mu d1-8 fusions with a nitrate-induced Lac⁺ phenotype were obtained. When oxrA::Tn 10 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.