Structure in Nucleated Erythrocytes

Abstract

The structure of the nucleated erythrocyte of frog and chicken has been investigated by electron microscopy and correlated with the distribution of haemoglobin and DNA-containing material determined by haem absorption and Feulgen staining in the light microscope. The nuclei of both species are found to contain haemoglobin which is continuous with the haemoglobin in the cytoplasm through holes or pores in the nuclear envelope. In addition the nucleus of the frog erythrocyte sometimes contains a single invagination which is lined by the nuclear envelope. The structure of the nuclear envelope and the pores and the organisation of the nucleus are similar to those already described for other somatic cells. Erythrocytes differ from the cells previously studied in that a continuity, via the nuclear pores, of chemical substance in the interior of the nucleus and in the cytoplasm can be directly demonstrated. This is due to the fact that the cytoplasm of erythrocytes is simple, consisting predominantly of haemoglobin, and that haemoglobin is easily recognised by its specific absorption. The static pictures obtained by electron microscopy have been supplemented by observations in phase-contrast of the changes in refraction of the cell contents due to the diffusion of the haemoglobin from the nucleus into the cytoplasm during haemolysis.

The Use of 55fe in High-Resolution Radioautography of Developing Red Cells

“…Since these dense chromatin masses are large in late erythroblasts, it is likely that overlying silver grains are due to 55 Fe disintegrations within these masses, and that labeled hemoglobin is dispersed throughout the entire nucleus. The presence of nuclear label agrees with an earlier ultrastructural report which indicates that hemoglobin occurs within this or ganelle in nucleated erythrocytes (Davies, 1961) and also supports data that suggest the presence of hemoglobin within condensed chromatin (Tooze and Davies, 1963).…”

Ouabain-insensitive salt and water movements in duck red cells. III. The role of chloride in the volume response.

“…Furthermore, the nucleus of the bird cell forms a smaller fraction of the cell volume than is the case with amphibian red cells. It is difficult to understand how the nucleus can concentrate sodium without binding when one considers the large pores seen in electron micrographs of the nuclear membrane of avian red cells (Davies, 1961)i For these reasons, it is probably not too far wrong to use total cell sodium values in the computation of ENa.…”

A General Method for the Specific Staining of Intracellular Antigens with Ferritin-Antibody Conjugates

“…1) confirm that hemoglobin is present within inclusions inside the nucleus of the avian red blood cell, a conclusion previously arrived at from chemical studies of isolated nuclei,'9 and inferred from the optical densities in electron micrographs. 20 The presence of cytoplasmic components inside cell nuclei2' has many physiological implications and could be studied in detail by this staining procedure. It may also be noted in Figures 2 and 3 that not all of the bacteriophage T4 particles in a given cell are stained with specific F-C antibody.…”