[Synthesis of ribosomal proteins in early development of the loach]. / Sintez ribosomnykh belkov v rannem razvitii v'iuna

The synthesis of ribosomal proteins (r-proteins) in the loach embryos was studied by the way of analysis of protein-labeled ribosomes isolated from the cytoplasm and purified from de novo synthesized polypeptide and contaminating proteins. The ribosomes at the mid-blastula and mid-gastrula stages were shown to contain no de novo synthesized proteins. The synthesis of r-proteins at the stage of organogenesis was revealed by sedimentation analysis of ribosomes in the gradient of sucrose concentrations, density analysis in the gradient of cesium chloride and analysis of the distribution of radioactivity in r-proteins separated from the labelled ribosomes by electrophoresis in polyacrilamide gel. At the stage of organogenesis, the exchange of ribosomal proteins with de novo synthesized r-proteins continues under the conditions of complete inhibition of RNA synthesis and incubation of unlabeled ribosomes with the labelled cytosol. The correlation between the absence of rRNA and r-protein syntheses at the early developmental stages and possible causes of the independence of r-protein synthesis and exchange from the simultaneous rRNA synthesis at the stage of organogenesis are discussed.

[Changes in the growth rates, respiration level and mitochondrial mass of the heart during chick embryo development]. / Izmenenie tempov rosta, urovnia dykhaniia i massy mitokhondrii serdtsa vo vremia razvitiia kurinogo zarodysha.

The growth of heart during the chick embryo development is accompanied by the increase in total protein content per weight unit of the organ and in the content of the actomyosin complex proteins calculated to the total heart protein. Changes in the rate of heart respiration during development are determined, mainly, by the mass of mitochondria. The growing heart at the early developmental stages is characterized by a very high rate of doubling of the mitochondrial protein mass.

[Protein synthesis in loach embryos isolated from the yolk and cultivated in vitro]. / Sintez belka u izolirovannykh ot zheltka zarodyshei v'iuna pri kul'tivirovanii in vitro.

Changes in protein synthesis in the loach (Misgurnus fossilis) blastoderms cultivated in vitro in the Holtfreter solution after their separation from the yolk at the early and late-blastula stages were assessed by biochemical and autoradiographic methods. The embryos incubated in vitro at the from blastula stage are characterized by the sharp activation of protein synthesis and the vegetal-animal gradient of protein synthesis, as well as in the control embryos; such embryos gastrulate and proceed to primary differentiation. On the contrary, in the embryos incubated from the early blastula stage the protein synthesis is inhibited and no regional differences in its intensity are noted; such embryos do not proceed to gastrulation. Possible causes of the protein synthesis activation in differentiating blastoderms and interrelationship between the character of protein synthesis and the ability of embryos for differentiation are discussed. The protein synthesis activation and the vegetal-animal gradient appearance are considered as a biochemical criterion of primary differentiation during gastrulation in fish embryos.

[Characteristics of cardiac growth and energy metabolism in the development of the clawed toad]. / Osobennosti rosta i énergeticheskogo obmena serdtsa v razvitii shportsevoi liagushki.

The relative content of the actomyosin complex proteins increases with respect to the total heart protein during the heart growth in Xenopus laevis. The intensity of the heart sections respiration was shown to depend on the heart weight. Constants were determined in an equation describing this dependence. The decrease in the intensity of the heart sections respiration is determined mainly by the decrease of the mitochondrial protein content.

[Substrate specificity of multiple forms of glucose-6-phosphate dehydrogenase in Misgurnus fossilis loach embryos]. / O substratnoi spetsifichnosti mnozhestvennykh form gliukozo-6-fosfat-degidrogenazy.

Studies have been made on substrate specificity of electrophoretically different forms of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+-1-oxidoreductase; EC 1.1.1.49). 2-Deoxy-D-glucose-6-phosphate produced by enzymic synthesis was used as a substrate analogue for G-6-P DH fractionated by polyacrylamide gel electrophoresis. The data obtained indicate that two forms of G-6-P DH of the loach blastoderm differ with respect to their substrate specificity.