Figure 5.

The effects of thioredoxin system mutations on bacterial survival in host serum and host macrophages. (A) The survival rate of WT, ΔtrxB, ΔtrxA and ΔtrxC against non-immune fish serum. Strains in the early logarithmic phase were incubated with non-immune tilapia serum or PBS (control) for 1 h. The number of viable bacteria was determined. (B) Edwardsiella piscicida replication in macrophages. The murine macrophage cell line RAW264.7 was incubated with WT, ΔtrxB, ΔtrxA and ΔtrxC for 2 h. After killing and washing extracellular bacteria, the macrophages were cultured for different lengths of time. At each time point, the viable intracellular bacteria were determined. Data are presented as the means ± SEM (N = 3). N, the number of times the experiments were performed. p values were obtained by analysis of variance using SPSS 23.