Hemoglobin synthesis during amphibian metamorphosis. I. Chemical studies on the hemoglobins from the larval and adult stages of Rana catesbeiana

Erythroid cell differentiation and the inhibition of cytokinesis by cytochalasin

Cytochalasin B produces multinucleated erythroid cells in tissue cultures of very young chick blastoderms. There is no apparent qualitative interference with differentiation and maturation of erythroid cells, but the amounts produced are reduced 4- and 10-fold. These effects of cytochalasin are readily reversible.

Developmental changes of erythropoiesis in cultured chick blastoderms

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.

Polyacrylamide gel electrophoresis

Polyacrylamide gel electrophoresis (PAGE) provides a versatile, gentle, high resolution method for fractionation and physical-chemical characterization of molecules on the basis of size, conformation, and net charge. The polymerization reaction can be rigorously controlled to provide uniform gels of reproducible, measurable pore size over a wide range. This makes it possible to obtain reproducible relative mobility (Rf) values as physical-chemical constants. Application and extension of Ogston's (random fiber) model for a gel allows for calculation of molecular volume, surface area, or radius, free mobility, and valence from RJ measurements at several gel concentrations, to calculate gel concentration for optimal resolution, and to predict behavior of macromolecules on gel gradients by computerized methods. Extension of classical moving boundary theory has been used to generate multiphasic buffer systems (providing selective stacking, unstacking, restacking, and preparative steady-state-stacking) with known operating characteristics for any pH at 0 degrees and 25 degrees C. A general strategy for isolation of macromolecules and for macromolecular mapping has been developed. Preparative scale PAGE is operational for milligram loads and feasible for gram quantities.

Specificity of mRNA binding factor in eukaryotes

It has been shown previously that ribosomal factors removed from chick muscle ribosomes by a high salt wash are required for both the binding of muscle mRNA to ribosomes and mRNA-directed synthesis of myosin on reticulocyte ribosomes. These factors can be separated into several components on DEAE-cellulose. A factor eluting between 0.18 and 0.25 M KCl is responsible for binding mRNA to the ribosome. This binding factor shows specificity in the recognition of mRNA, as has been demonstrated by the preferential binding of muscle and globin mRNA to ribosomes which contain their respective binding factors. Similarly, globin mRNA is preferentially translated when reticulocyte factors are present on the ribosome.

Electrophoretic analysis of hemoglobin and isozymes in individual vertebrate cells

Electrophoretic patterns of enzymes in single vertebrate erythrocytes may be visualized with the use of capillary tube polyacrylamide columns and stains which amplify the enzymatic activity. The following points have thereby been demonstrated:1. Peripheral blood of metamorphosing bullfrogs (Rana catesbeiana) contains two molecular forms of hemoglobin: embryonic (tadpole) and adult (frog). Only one of these forms is found in each erythrocyte.2. Human umbilical cord blood contains fetal and adult hemoglobins; both forms may be found in individual erythrocytes, in varying proportions.3. Both lactate dehydrogenase isozymes found in whole blood of bullfrogs and humans are found in individual erythrocytes, but the proportions differ from cell to cell.

Aging of alpha-crystallins during development of the lens

Fetal alpha-crystallin from the bovine lens can be resolved into three major subunit fractions by ion exchange chromatography. A fourth subunit gradually arises during the development of the lens. Incorporation studies indicate that this subunit is not formed by de novo synthesis but by the chemical conversion of one subunit into another. Possible mechanisms for this conversion are discussed.

Tadpole Antibodies against Frog Hemoglobin and Their Effect on Development

Rana catesbeiana tadpoles immunized with the main hemoglobin component of the adult frog of the same species produced precipitating and agglutinating antibodies against the immunogen. After natural metamorphosis, the immunized froglets have as their only major hemoglobin a protein immunologically and electrophoretically different from the major hemoglobin of control froglets.

Les hémoglobines des amphibiens: Caractérisation préliminaire des chaînes d'une hémoglobine de la grenouille Rana esculenta (L)

A frog (Rana esculenta) hemoglobin has been purified and two types of chain have been separated by countercurrent distribution, N- and C-terminal sequences of each chain have been determines. The N-terminal amino acids are Acetyl-Ala and Gly. The acetylated chain seems to belong to the alpha-chain series and the glycine chain to the beta-chain series.