FIGURE 10.

Trypsin and chymotrypsin activity in the different midgut regions. (A) Trypsin activity in midgut juice extracted from anterior, middle, and posterior midgut. For each tract the enzymatic assay was performed at pH 8.5. The values are reported as mean ± SEM of 3 experiments. Different letters denote significant differences (ANOVA test followed by Tukey’s test. ANOVA p-value < 0.001, Tukey’s test p-values: Middle vs. Anterior p = 1.000, Posterior vs. Anterior p < 0.001, Posterior vs. Middle p < 0.001). (B) Dependence of trypsin activity on temperature in midgut juice from the posterior region of the midgut performed at pH 8.5. Relative activity values (%) are reported as mean ± SEM of at least 3 experiments and are expressed as percentage of the highest activity over the temperature range examined. (C) Dependence of trypsin activity on pH in midgut juice from the posterior region of the midgut performed at 45°C. Relative activity values (%) are reported as mean ± SEM of at least 3 experiments and are expressed as percentage of the highest activity over the pH range examined. (D) Chymotrypsin activity in midgut juice extracted from anterior, middle, and posterior midgut. For each tract the enzymatic assay was performed at pH 8.5. The values are reported as mean ± SEM of at least 3 experiments. Different letters denote significant differences (ANOVA test followed by Tukey’s test. ANOVA p-value < 0.05, Tukey’s test p-values: Middle vs. Anterior p = 0.845, Posterior vs. Anterior p < 0.05, Posterior vs. Middle p = 0.061).