Long-term experiment showing antibacterial activity in the midgut of
Trypanosoma rangeli. Antibacterial activities of anterior midgutof R. prolixus 5th instar nymphs 7 days after feeding (DAF) on blood without parasiteswere tested against (A)
E. coli. Treatments: white columns – control, uninfected group; black columns – infected group. Previously, 4th instar nymphs were fed on inactivated blood with or without 1 × 106 epimastigotes/mL. Anterior midgut contents were collected from 5th instar nymphs 7 (DAF). Antibacterial activity was measured using the turbidimetric assay (TB) (OD550 nm) after 19 h incubation of midgut samples with different bacteria and calculated by the difference between the optical densities of the midgut samples and bacterial control. Bars represent mean ± SEM of three independent experiments. Each experiment consisted of three pools of three insects (n = 9). Means were compared using Student T-test; ***p < 0.001 and *p < 0.05.