Sothern blotting investigation of truncated linear plasmid. A. Analysis of tir region of pBSSB1 and derivatives using labelled DNA prepared from a PCR amplicon (primers tir_f and tir_g) generated with template DNA from S. Typhi 404ty-fliC(d) as probe against genomic DNA digested with EcoRV. Lanes: 1, S. Typhi 403ty-fliC(j); 2, 403tya; 3, 403tyb; 4, 403tyc; 5, 403tyd; 6, S. Typhi 404ty-fliC(d); 7, 404tya; 8, 404tyb; 9, 404tyc and 10, 404tyd. Sizes estimated to migration of Hyperladder I (Bioline). B. Analysis of new right terminus of the truncated plasmids. Genomic DNA digested with SacI and probed with a PCR amplicon specific for the 5′ region of the fljBz66 gene generated with template DNA from S. Typhi 404ty-fliC(d). Lanes as Fig. 5A.