High Voltage (1MeV) EM image of a metaphase chromosome isolated from CHO cells using a non-aqueous technique, squashed in 1:1 acetic acid:ethanol and transferred to an EM grid. A chromatid pair occupies the center of the image. This micrograph was captured at a specimen tilt of 55 degrees. The accompanying image has a tilt of 45 degrees, creating a stereo pair that provides an oblique stereo view of the chromatids.
Cells were metaphase arrested with colcemid, then exposed to a low ionic strength medium (0.07M phosphate buffer)containing 50% D20 as a microtubule stabilizer. Preparations were squashed in 3:1 acetic acid:ethanol,stained, and transferred to an EM grid. See also: H. Ris 1981 Stereoscopic electron microscopy of chromosomes. Meth Cell Biol 22:77-96 H. Ris 1978 Preparation of chromatin and chromosomes for electron microscopy. Meth Cell Biol 18:220-246.