Figure 2. B. thailandensis growth at 18°C is slower than at 25°C.

(A) Survival of wild-type flies infected with wild-type B. thailandensis E264 and kept at 18°C. (B) Infected and control flies were kept at 18°C, and subgroups were shifted to 25°C at time points 7.5 and 10.5 days after infection. Dead flies were counted twice a day. The result indicates that bacteria recovered at 25°C, and killed the flies fast. (C) B. thailandensis was injected at an initial dose of OD600 = 0.01. Flies were kept at 18°C (grey) and shifted to 25°C (black) at time points 7 and 10 days p.i. Subsets of equally treated flies were kept at 18°C as controls (grey). Samples were homogenised 24 h after shifting from 18 to 25°C to determine the growth of bacteria inside the flies. Samples were analysed at time points 3, 7, 8, 10, 11, and 15 days p.i. Bacterial growth was determined by plating dilutions of homogenised infected and control flies in PBS. Plated bacteria were left at 37°C for 24 h, when bacterial colonies were counted. Data is based on one experiments; n = 7 flies. Statistical significance of bacterial growth was determined using Mann-Whitney test (GraphPad Prism); ** p<0.002, *** p<0.001. Y-axis  =  log10.