Developmental Changes of Erythropoiesis in Cultured Chick Blastoderms

Abstract

The erythropoietic area of very early chick embryos was cultured as a tissue for up to nine days to study the changes in red cell type and hemoglobin type, the cell cycle time, the cell population kinetics, and the DNA synthetase activity of these cells . It was found that the area vasculosa without the participation of the embryo proper contained the information and the timing mechanism required to produce not only the early primitive erythroid cell population, but also in due course, the later definitive cell type, each with its appropriate hemoglobin types . Also the precursors of the definitive cell type are active in DNA synthesis and therefore are probably in cycle very early in the culture period .

Primitive and definitive erythropoiesis in the yolk sac: a birds eye view

“…During the period of E4, hematopoietic markers are rapidly downregulated in circulating primitive erythrocytes, and definitive hematopoietic/erythropoietic clusters appear in the yolk sac venous vessels and small capillary vessels . Interestingly, it is also during this period that most primitive erythrocytes have been reported to undergo the last mitotic division among on average six divisions from the earliest megaloblast/hemocytobalst stage, and enter post-mitotic stage Hagopian and Ingram, 1971;Weintraub et al, 1971) (Fig. 4).…”

The Amino Acid Sequences of the α- and β-Globin Chains of Hemoglobin from the Aldabra Giant Tortoises, Geochelone gigantea

“…Among them, hemoglobin D (Hb D) was first found in birds as a minor component of the embryonic and adult definitive erythrocytes (Hagopian and Ingram, 1971;Brown and Ingram, 1974). Based on functional studies of Hb D, the presence of α D -globin raises the oxygen affinity and might be one such adaptation of insufficient oxygen supply as observed in the embryonic stages (Dodgson et al ., 1981;Chapman et al ., 1982) or extreme hypoxic and even anoxic conditions (Rücknagel and Braunitzer, 1988).…”

Erythroid Cell Differentiation and the Inhibition of Cytokinesis by Cytochalasin

“…The red cells were usually harvested in 207 0 phick serum in medium 199 by tearing the tissue and allowing the cells to pour out (Hagopian and Ingram, 1971) . Sometimes the tissue had to be teased to free the red blood cells.…”

“…For the determination of hemoglobin production or for electrophoresis, the cells were lysed in water in the presence of toluene and carbon tetrachloride, as described elsewhere (Hagopian and Ingram, 1971) ; hemoglobin was estimated by the Drabkin procedure (1935) . Hemoglobin electrophoresis was carried out by the acrylamide gel technique described by Moss and Ingram (1968) .…”

“…They were incubated for 24 or 36 hr, yielding embryos at the head fold and the six to nine somite stage, respectively . Blastoderms were prepared in sterile chick Ringer solution under sterile conditions (Hagopian and Ingram, 1971) . Usually the whole blastoderm was cultured, dorsal side up, on cellulose acetate discs (I%e inches diameter, 0 .45 .t pore size ; Schleicher & Schnell, Inc ., Keene, N. H., or Matheson-Higgins Co ., Cambridge, Mass .)…”