Figure 5. The Tsp_PR secreted molecule(s) do not affect bacterial load or DENV infection in aseptic mosquitoes.

(A) Bacterial growth inhibition assay. Six bacterial isolates of field-caught mosquitoes (Ramirez et al., 2012) were independently plated on LB agar and covered with a disk soaked in a Tsp_PR secretome solution or antibiotic cocktail. Three isolates were Gram-negative bacteria: Serratia marcescens (a), Chromobacterium haemolyticum (b), and Enterobacter hormaeche (c). Three were Gram-positive bacteria: Bacillus subtilis (d), Staphilococcus capprae (e), and Lactococcus lactis (f). Bacterial inhibition was indicated by the presence of a bacterial inhibition zone around the disk. (B) Total bacterial loads. Midguts of secretome solution-exposed and unexposed mosquitoes were collected, homogenized, and plated on LB agar. Bacteria were counted as CFU. Error bars represent ± SD of three independent experiments p=0.202. (C) DENV titers in aseptic mosquitoes. Mosquitoes were treated with an antibiotic cocktail via a sugar meal 4 days before the fungal treatment and were mock-fed or fed for 48 hr on a Tsp_PR secretome solution prior to DENV infection. Each dot represents the PFU after 7 dpi in individual midguts from three independent experiments (Control, N = 75; Tsp_PR, N = 78). The line indicates the mean, p=0.867. Upper right box shows the prevalence of infected mosquitoes, error bars represent the 95% confidence interval.