Three‐Dimensional View Of The Chromatin In Freeze‐Fractured Chicken Erythrocyte Nuclei

Abstract

The freeze-fracture thaw-fix (FfTF) technique described in earlier papers is applied in the present work to more detailed study of the chicken erythrocyte, by transmission replicas and high resolution scanning electron microscopy (3 nm scan beam size). The three-dimensional structure of the chromatin, and possibly the non-histone protein matrix, of fractured nuclei is to a large extent retained in this method of preparation and seen in stereomicrographs. In these micrographs the helical sub-structure of the 25 nm chromatin strands can be seen at about the same resolution as that of previously published micrographs in which extracted chromatin is viewed by negative contrast or after metal shadowing. The useful resolution of the secondary electron micrographs, for a suitably mounted specimen, is shown to be as good as that of transmission micrographs of platinum-carbon replicas of the same material.

The intermediate filaments in human hepatocytes.

“…Although the role of IFs is not yet clear (Klymkowsky 1981), it is generally accepted that they play some role in the movement and positioning of nuclei and other organelles (Lento et al 1978;Lazarides 1980;Wang and Choppin 1981). Some morphological evidence that IFs are connected with the plasma membrane and cytoplasmic organelles including the nucleus (Franke et al 1979;Haggis and Bond 1979;French et al 1982;Granger and Lazarides 1982;Ramaekers et al 1982;Ishii et al 1984), though still controversial about the presence of connection, may support this view. As to hepatocytes, there has been no report that showed direct connection of IFs with nucleus and plasma membrane morphologically.…”

“…The Intermediate Filaments in Human Hepatocytes 327 Granger and Lazarides (1982), and Haggis and Bond (1979) demonstrated threedimensionally that fine filaments run from the outer surface of the nucleus to the inner surface of the plasma membrane. Ramaekers et al (1982) described using calf lenses an intimate association between IF and the lipid bilayer of the plasma membrane ; IF appeared mainly associated with the protoplasmic fractured face of the membrane in freeze-fracture study.…”

Three-dimensional ultrastructure of apoptotic nuclei in rat prostatic epithelial cells revealed by a quick-freezing and deep-etching method

“…They were 20-to 30-nm-thick fibers, 5-to 10-nm filaments, and also 2-to 5-nm fine filaments, forming network structures. The 20-to 30-nm fibers and 5-to 10-nm filaments probably corresponded to 30-nm chromatin fibers and 10-nm nucleosomal filaments, respectively, as reported before [18][19][20]. The 2-to 5-nm filaments could be DNA strands themselves, which were free of histone proteins.…”

Field‐emission scanning electron microscopy of the internal cellular organization of fungi

“…Other than immersion, tissues such as lung and kidney have been successfully fixed by perfusion fixation (Jongebloed andKalicharan 1994, Tanaka andMitsushima 1984). In other cases, single cells are embedded in fibrin gels (Haggis and Bond 1978) or in chitosan (Fukudome and Tanaka 1986) prior to fixation. Plant material, such as root tips, was first infiltrated with saponin (Vesk et al 1994).…”