P. Walther et M. Muller, Biological ultrastructure as revealed by high resolution cryo-SEM of blockfaces after cryo-sectioning, J MICROSC O, 196, 1999, pp. 279-287
Ultrastructural information was obtained by imaging the block face of high-
pressure-frozen cryo-sectioned biological samples in a high-resolution cryo
-SEM, Cryo-sectioning leads to a well-defined flat artificial surface in co
ntrast to cryo-fracturing, Typical artefacts of cryo-sections such as compr
ession and crevasses were not visible on the block face, The ultrastructura
l features known from resin sections and from freeze-fractures could also b
e found on the block faces. The cytoplasms show particles of different size
which most likely represent proteins. The effects of radiation damage coul
d be reduced considerably by applying the double layer coating technique an
d backscattered electron imaging,
High quality cryo-sections are only obtained from vitrified material. Reaso
nably flat block faces were, however, also obtained from adequately frozen
microcrystalline samples, thereby facilitating ultrastructural studies in t
he frozen hydrated state.