The morphology of erythroid cells separated by density gradient centrifugation through ficoll

Abstract

The regenerating blood of geese injected with phenylhydrazine was subjected to large scale, zonal centrifugation through density gradients of Ficoll. In this way, erythroid cells were fractionated according to their respective stages of development. Highly enriched fractions were obtained, containing cells that were well preserved as assessed by both light and electron microscopy. The separated cells exhibited ribosome density and nucleic acid and protein staining patterns typically associated with erythrocyte differentiation. Morphometric analysis of nuclei indicated that despite an apparent net increase in the amount of compact chromatin during development, comparatively little difference existed between the volumes of condensed chromatin present in immature and mature cells. Instead, there was a three fold decrease in nuclear volume between young erythroblasts and reticulocytes, coupled with a concomitant decrease in the volume occupied by dispersed chromatin, RNP and nucleoli. These observations are discussed in relation to molecular changes associated with nuclear differentiation in erythroid cells.

Mutant Mouse L‐Cells: A Model for Megaloblastic Anaemia

“…Since the volume of condensed chromatin in both ts A1S9 and ts CI does not decrease during nuclear modification (Figs 8b and 9b), this implies a dilutional effect on previously condensed chromatin as the nucleus doubles in volume. A similar illusionary effect has been reported during differentiation of erythrocytes (Brasch et al, 1977;Dardick & Setterfield, 1976), and in a recent electron microscope study, Wickramasinghe & Bush (1977) note that the nuclei of some myelocytes from patients with megaloblastic anaemia appear to have decreased amounts of condensed chromatin. Furthermore, during expression of the mutation the dispersed appearance of nuclear profiles appears to occur as a result of reorganization of previous large aggregates of condensed chromatin into numerous small, possibly looser, clumps (Setterfield et al, 1977).…”