Fig 4.

Complementation in trans reverses the observed phenotypes of ΔSTM3602 and ΔSTM3846 mutants. Ligated ileal loops from five calves were inoculated with the WT and the targeted deletion mutant complemented with an intact copy of the corresponding open reading frame in trans (open symbols). Data from the competitive infection experiments between the WT and targeted deletion mutant (Fig. 3, closed symbols), and statistical significance allows direct comparison to complementation data. (A) Competitive index for the wild type versus the complemented ΔSTM3602 mutant. (B) Competitive index for the wild type versus the complemented ΔSTM3846 mutant. In all panels, short solid black bars indicate the median values. Two asterisks indicate statistically significant differences between the ratio of the mutant and wild type in the inoculum and the ratio in the material collected at the termination of the infection (“output” ratio) (P < 0.05) between groups as determined by a two-tailed Student t test.