Fig 8. Immune responses of G. mellonella after challenge by B. bassiana wild type and UV-killed cells with or without addition of purified BbEng1.

A. The phenoloxidase (PO) activities at indicated time points after injection. B. H₂O₂ (ROS) levels during fungal infection. C. Expression levels of genes involved in the Toll pathway, antimicrobial peptide (AMP) and proPO system in the larvae 12 h post-injection (β-actin used as a reference for normalized fold expression, NFE). D. Effects of added 0.5 μM BbEng1 or iBbEng1 (heated-inactivated BbEng1) on fungal cell wall (UKC, UV-killed B. bassiana conidia, 5 × 10⁶ conidia / mL)-activated PO activity (total volume: 2 μL). Hemolymph samples taken at 12 h after injection of UKC, UKC + BbEng1 or UKC + iBbEng1 were used for PO assay. Larvae injected with 2 μL of 0.85% NaCl or UKC+ BSA (bovine serum albumin, 0.5 μM) were used as controls. E. Expression levels of genes in the Toll pathway components, AMP proPO-system-associated genes in the larvae at 12 h after injection of UKC or UKC + proteins (β-actin used as the reference). F, G. Microscopic images and fluorescence intensities of UKC and conidia (CO) (n > 100) labeled with FITC-labeled BbEng1. Error bars: SDs. Different letters indicate significant differences (P < 0.01 in LSD test).