Fig. 3. ATPase activities in crude extracts of Malpighian tubules of Aedes aegypti. The V-type H⁺-ATPase activity was measured as the bafilomycin- and NO₃^--sensitive ATPase activity. The Na⁺/K⁺-ATPase activity was measured as the ouabain- and vanadate-sensitive ATPase activity. The following inhibitor concentrations were used: bafilomycin A₁, 0.025 mmol l^-1; nitrate, 100 mmol l^-1; ouabain, 1 mmol l^-1; vanadate, 0.1 mmol l^-1. Asterisks represent P<0.01. The number of determinations is shown in parentheses.