Electron microscopic studies of erythroid cells and their isolated nuclei in Xenopus Laevius
Electron microscopic studies of erythroid cells and their isolated nuclei in Xenopus Laevius
Adult Xenovue laevis, rendered anaemic by phenylhydrazine injection have been studied during the recovery from such anaemia. Anaemia induced by phenylhydrazine resulted in stimulation of erythropoiesis and electron microscopic observation indicated that both the liver and spleen r e the sites of erythroid cell production. Electron microscopic observation suggests that there is a sudden release of a large number of immature erythroid cells (basophilic erythroblast) from liver and spleen, into the blood circulation. This is followed by mitosis of this new population in the circulation. No further release of erythroid cell from these organs is likely, until complete recovery from anaemia has occurred. Electron microscopy of liver and spleen also indicated that both organs are active in the phagocytosis and destruction of the old damaged red blood cells. These observations showed that liver, and to a lesser extent, spleen are the sites of red cello sequestration in the early days of anaemia. Finally, the spleen plays an important role in phagooytosis, until complete destruction of the damaged red blood cells has occured. This may account for spleen involvement as the site of red cell destruction in normal healthy Xenopus. Electron microscopic observation suggests that gross chromatin condensation within the isolated Xenopus erythrocyte nucleus, after the isolation, seems to be largely determined byothe ionic concentration of the isolating medium. The 200A beaded chromatin fibres observed in vivo are maintained in22edia containing MgCl and CaC12,'but not those containing & as2$ the divalent cation. In the presence of divalent cation (Mg or Ca) decreasing ICC1 concentration causes peripheral condensation towards the nuclear membrane. Monovalent cation alone does not appear capable of inducing peripheral condensation. Ultrastructural studies of thin sections of isolated Xenopus erythrocyte nuclei under varying ionic conditions has revealed four different morphologies with characteristic chromatin conformations. An attempt has been made to study electron micrographs of thin nuclear sections using computer image analysis of their intensity of staining with uranyl acetate/lead citrate. This is explained by a model which suggests that there are only 'four conformation that chromatin can assume within the nucleus.
University of Southampton
1980
Chegini, Nasser
(1980)
Electron microscopic studies of erythroid cells and their isolated nuclei in Xenopus Laevius.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Adult Xenovue laevis, rendered anaemic by phenylhydrazine injection have been studied during the recovery from such anaemia. Anaemia induced by phenylhydrazine resulted in stimulation of erythropoiesis and electron microscopic observation indicated that both the liver and spleen r e the sites of erythroid cell production. Electron microscopic observation suggests that there is a sudden release of a large number of immature erythroid cells (basophilic erythroblast) from liver and spleen, into the blood circulation. This is followed by mitosis of this new population in the circulation. No further release of erythroid cell from these organs is likely, until complete recovery from anaemia has occurred. Electron microscopy of liver and spleen also indicated that both organs are active in the phagocytosis and destruction of the old damaged red blood cells. These observations showed that liver, and to a lesser extent, spleen are the sites of red cello sequestration in the early days of anaemia. Finally, the spleen plays an important role in phagooytosis, until complete destruction of the damaged red blood cells has occured. This may account for spleen involvement as the site of red cell destruction in normal healthy Xenopus. Electron microscopic observation suggests that gross chromatin condensation within the isolated Xenopus erythrocyte nucleus, after the isolation, seems to be largely determined byothe ionic concentration of the isolating medium. The 200A beaded chromatin fibres observed in vivo are maintained in22edia containing MgCl and CaC12,'but not those containing & as2$ the divalent cation. In the presence of divalent cation (Mg or Ca) decreasing ICC1 concentration causes peripheral condensation towards the nuclear membrane. Monovalent cation alone does not appear capable of inducing peripheral condensation. Ultrastructural studies of thin sections of isolated Xenopus erythrocyte nuclei under varying ionic conditions has revealed four different morphologies with characteristic chromatin conformations. An attempt has been made to study electron micrographs of thin nuclear sections using computer image analysis of their intensity of staining with uranyl acetate/lead citrate. This is explained by a model which suggests that there are only 'four conformation that chromatin can assume within the nucleus.
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Published date: 1980
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Local EPrints ID: 462748
URI: http://eprints.soton.ac.uk/id/eprint/462748
PURE UUID: b615547d-5535-467f-9272-69236fe674e9
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Date deposited: 04 Jul 2022 19:51
Last modified: 04 Jul 2022 19:51
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Author:
Nasser Chegini
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