Figure 6.

Involvement of paenilarvin in swarming motility of P. larvae ERIC II. Wild-type P. larvae ERIC II (DSM25430 wt) and a corresponding inactivation mutant for the paenilarvin gene cluster (DSM25430 Δitu) were tested in swarming assays. Bacterial suspensions (10 µl) with an OD₆₀₀ of 0.1 were inoculated centrally onto a brain heart infusion (BHI; 0.5%) agar plate and incubated at 37 °C for seven days. Pictures were taken at one, two, three, six, and seven days post inoculation. Three biological replicates with three technical replicates each were performed. (A) Representative pictures for each day and strain (DSM25430 wt, upper row; DSM25430 Δitu, lower row) are shown. Uncolonized agar is black and bacterial biomass is milky white to white. (B) Swarm radii were measured for each strain and time point. Data represent mean values ± SEM of three independent experiments each with three technical replicates. Statistical analysis of the difference in swarming motility between DSM25430 wt (dark gray columns) and DSM25430 Δitu (off-white columns) was performed with an unpaired Student’s t-test for each time point (not significantly different: n.s., p ≥ 0.05; significantly different: *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001).