Enteritidis 11 (SE11) strain. After selecting for the ApR marker of the plasmid, the presence of pFOL1111 and the expression of IS30–FljA fusion transposase were confirmed. Subsequently, the insertion donor pFOL1069 from E. coli S17-1 λpir bacteria was conjugated to SE11(pFOL1111)ApR and the transconjugant bacteria were selected for CmR of pFOL1069 and the auxotrophy of the wt S. Enteritidis strain (Fig. 2). In the control experiment, the wt IS30 transposase producer plasmid pJKI132 was used instead of pFOL1111, where only the IS30 transposase was expressed without the FljA domain. In this case, the insertion pattern of

selleck chemical wt IS30 was expected due to the lack of the FljA-specific DNA-binding ability. Performing the transposon mutagenesis on the wt SE11 strain using both the IS30–FljA fusion or the wt

IS30 transposase, the results of three independent experiments (Supporting Information, Table S1) showed that the transpositional frequency mediated by the IS30–FljA fusion transposase (1.78E-04–1.62E-04) was as high as that of the wt IS30 transposase (1.45E-04–8.35E-05). The selleck chemicals data indicated that the fusion transposase maintained full activity compared with the wild type. The CmR transposon mutant Salmonella bacteria carrying pFOL1069 insertion in their genome were selected and tested for motility. As a result of the mutagenesis experiments, altogether 1200 randomly selected check details ApRCmR SE11 transposon mutants were isolated and investigated: 600 were generated by the IS30–FljA fusion transposase and 600 by the wt IS30 transposase, respectively. The motility of the mutants was tested individually using the motility agar tube test. Four out of 600 mutants (0.67%) generated by the site-directed system proved to be completely nonmotile. In contrast, no nonmotile mutants were detected among the 600 mutants (<0.16%) generated by the wt IS30

transposase. At least three of the four nonmotile insertional mutants could be considered as independent mutants, originating from three independent experiments (Fig. 3b, column 3). These insertional mutants were confirmed as nonflagellated phenotypes using S. Enteritidis-specific Hg,m antiserum. At the same time, all of the four investigated mutants retained their agglutinability in group D antiserum. Thus, they were confirmed as flagella-free derivatives of SE11. In order to determine the target specificity of the IS30–FljA fusion transposase, altogether 40 different pFOL1069 insertions were cloned (see Materials and methods) and the integration sequences were identified. On analysing the target sequences (Table 1a), it was found that the IS30–FljA fusion transposase show pronounced target specificity. The consensus sequence derived from 24 insertion sites (Table 1b) showed high similarity to the previously determined CIG consensus of insertions of the wt IS30 in the genome of E. coli.