Figure 9. Sterile midguts have highly resistive apical membranes (pooled data).

A–B, bath application of Bf on posterior midguts of non‐sterile larvae. A, Bf inhibited extrusion of H⁺, resulting in acidification of cells and pH_o alkalinized. B, Bf decreased [K⁺]_i in the enterocytes. C–H, pooled data of all Bf (250 nm Bf in Sch‐R) applications in non‐sterile and sterile larval midguts. Sterile larvae have decreased V _t (C), V _b (D), V _a (E), I _sc (F) and increased R _t (G), with fivefold higher R _a/R _b ratio (H). Number of experiments (n) is indicated in A and B and n shown in C also applies to D–H. Graphs show mean ± SEM. ^* P < 0.05, ^** P < 0.01, ^*** P < 0.001.