Figure 1

TnBVank1 induces apoptosis and stimulates caspase-3 activity in S2 cells stably expressing TnBVank1 gene (S2[ank1]). Apoptosis was induced in positive control S2 cells and S2 cells stably expressing TnBVank1 through a treatment with 1 µM camptothecin (S2 + CAM, S2[ank1] + CAM). (a) Cells were harvested and doubly labeled with Annexin V-FITC and PI before analysis by flow cytometry. Dot plots of single positive for Annexin V and double positive for Annexin V and PI cells were interpreted as signs of early and late phases of apoptosis respectively (lower and upper right quadrant respectively). Data are quantified in the bar chart on the right showing the percentage of apoptotic cells. (b) Caspase-3 activity was determined using Ac-DEVD-AMC as a fluorescent substrate. For the assay, 3 × 10⁵ cells were used. Results are expressed as fluorescence units (F.U.); an excitation wavelength of 380 nm and an emission wavelength of 440 nm were utilised. Data represent the mean of 3 replicates ± SD. Statistically significant differences are indicated with asterisks (*P ≤ 0.05, **P ≤ 0.01, one way ANOVA and Tukey’s Test P < 0.05).