B. thailandensis infection kills WT male D. melanogaster, survives and grows in the host.
(A) Oregon-R males were infected with WT B. thailandensis (B. thai) and died within 3.5 days of infection. Survival data was pooled from 3 independent experiments (n = min. 51 males per condition). Bacteria were injected at OD600 = 0.01, (approximately 250 CFU per fly). Mock-infected (PBS) controls were alive for the duration of this experiment. (B) B. thailandensis survived and multiplied inside infected flies. The data is based on 2 independent experiments (n = min. 11 males per time point). B. thailandensis was injected at a dose of OD600 = 0.01. Samples were collected at 0, 6 and 24 h p.i. and bacterial growth determined by plating dilutions of homogenised samples. Colonies were counted 24 h after the homogenate was plated and incubated at 37°C. Statistical significance of bacterial growth between time points was determined using Mann-Whitney test; * p<0.02 and *** p<0.0001. (C) B. thailandensis infection induced AMP expression in D. melanogaster. Three infection time points were analysed: 1, 6, and 24 h; controls were either mock-infected (PBS) or uninjected (NI). All tested AMPs were without exception significantly induced 24 h after infection. Levels of AMP mRNA were determined by qPCR. Statistical significance between levels of AMP expression was determined using Mann-Whitney test (GraphPad Prism); *** p<0.001. Data is based on 1 experiment, n = 7 males per condition; error bars represent SD.