Figure 9

Competitive inhibition of 10 selected bacterial metabolites derived from X. nematophila and P. temperata temperata with 5-HT against Se-5HTR mediating phagocytosis. FITC-tagged E. coli cells were injected to L5 larvae along with test chemicals. After 15 min, phagocytic cells were observed under a fluorescent microscope at 400 × magnification and percentage of phagocytotic hemocytes was calculated from randomly chosen 100 cells. Each treatment was independently replicated three times. (a) Dose-response of inhibitory compound (0, 0.01, 0.1, 1, and 10 µg/larva) with a fixed 5-HT concentration (1 µg/larva). (b) Dose-response of 5-HT (0, 0.02, 0.2, 2 and 20 µg/larva) with a fixed HB compound concentration (1 µg/larva). ‘CON’ represents a positive control without any inhibitor.