Osmium tetroxide

Both SEM and TEM were employed to observe the tegument of siRNA-treated and control schistosomes. At 6 days post treatment, worms were collected and washed in PBS (pH 7.4) three times, and immediately chemically fixed with 4% paraformaldehyde and 2.5% glutaraldehyde (System Biosciences, Mountain View, CA, USA) at 4 °C for 48 h, followed by osmium tetroxide (System Biosciences, Mountain View, CA, USA) at room temperature. Then the worms were dehydrated in increasing concentrations (from 30% to 100%) of acetone (TiTan, Shanghai, China). For SEM, the samples were freeze-dried and coated with platinum (System Biosciences, Mountain View, CA, USA) by sputtering with a plasma multicoater (PMC-5000; Meiwafosis, Tokyo, Japan). For TEM, the dehydrated samples were embedded into resins (TiTan, Shanghai, China), and then thin sections were cut, transferred to metal grids (Agar Scientific, Essex, UK). Uranyl acetate (System Biosciences, Mountain View, CA, USA) was used for postsection staining. Images were captured with a scanning electron microscope (JSM-6390LV, JEOL, Tokyo, Japan) in high-vacuum mode with an accelerating voltage of 2–10 kV, or with a transmission electron microscope (Hitachi H-7600, Tokyo, Japan) with an accelerating voltage of 80 kV, respectively.

Worms were collected, washed with PBS (pH 7.4) three times, and then fixed with 4% paraformaldehyde and 2.5% glutaraldehyde (System Biosciences, Mountain View, CA, USA) at 4°C for 48 h, followed by osmium tetroxide (System Biosciences, Mountain View, CA, USA) at room temperature. Subsequently, the parasites were dehydrated with increasing concentrations (from 30% to 100%) of acetone (TiTan, Shanghai, China) for incubating. For SEM, the samples were freeze-dried and coated with platinum (System Biosciences) by sputtering with a plasma multicoater (PMC-5000; Meiwafosis, Tokyo, Japan). For TEM, the dehydrated samples were embedded into resins (TiTan, Shanghai, China) before thin sections were cut and transferred to metal grids (Agar Scientific, Essex, UK). Uranyl acetate (System Biosciences) was used for post-section staining. Images were captured with a SEM microscope (JSM-6390LV, JEOL, Tokyo, Japan) in high-vacuum mode with an accelerating voltage of 2–10 kV, or with a TEM microscope (Hitachi H-7600, Tokyo, Japan) with an accelerating voltage of 80 kV.