Figure 3

The evolutionary relationship between iam sequences and the expression profiles of the iam locus in cattle- and human isolates. A. The evolutionary relationship between iam sequences detected in C. jejuni isolated from human and cattle samples. The tree was drawn to scale using the Neighbor-Joining method. The percentage of replicate trees in which the iam sequences clustered together in the bootstrap test (10000 replicates) is shown next to the branches. The evolutionary distances are in the units of the number of base substitutions per site. B. Expression of iam as determined using qRT-PCR analysis. Bov-1 is an iam-negative strain. Wildtype strains (C. jejuni 81-176 and NCTC11168) that harbor the iam were also included for comparison with iam-containing cattle isolates. The data represented was collected using the primer set iam1; however, set iam2 resulted in similar results (data not shown). Expression in iam-negative strains was not detectable even after 35 cycles of amplification.