Figure 2
Effects of radiation damage and missing wedge artefacts on electron cryo-tomography images. (a) Two images from one series of tomographic acquisition. Top: ice-embedded flagellum tilted by 30°. Bottom: the same flagella without tilt. A gold label is shown by arrows. (b) Cross section of Chlamydomonas flagella with the membrane removed (left) and intact (right). The membrane is shown by arrows. Missing wedge artefacts generate non-isotropic density distributions. (c) Longitudinal (parallel to the microtubule) sections of averaged tomograms (ten particles) along microtubule doublets with high and low doses of electron beam. The averaged image with a high electron dose shows individual dynein molecules (arrows) even with ten particles. (d) Vertical sections of averaged tomograms (∼1000 particles) with high and low doses. By averaging many particles obtained under a low-dose condition better resolution is obtained. Averaging among nine doublets generates isotropic microtubules (even and round-shaped). (a) Scale bar = 250 nm. (b)–(d) Scale bar = 50 nm. |