[Determination of homoserine kinase activity by chromatographic separation and measurement of reaction products]. / Opredelenie aktivnosti gomoserinkinazy putem khromatograficheskogo razdeleniia i izmereniia produktov reaktsii.

A highly specific procedure for quantitative assay of the homoserine kinase activity in an optimized enzymatic reaction using 14C-labelled homoserine or [gamma 33P]-ATP as substrates, and paper or thin-layer chromatography for separation of the formed o-phosphohomoserine, is described. The procedure is simple, sensitive and allows the assay for the activity of both purified and non-purified homoserine kinases.

[Immunochemical properties of erythrocyte-specific histone H5 in salmonid fishes]. / Immunokhimicheskie svoistva éritrotsitspetsificheskogo gistona H5 u lososevykh ryb.

Comparative studies have been made on the immunochemical properties of histone H5 in Salmonidae species. High degree of homology between these histones and H5 histone from Oncorhynchus tschawytscha was demonstrated by microcomplement fixation. Properties of H5 histones in fish and birds are discussed.

Presence of histone H1o-related fraction in chicken liver.

The lysine-rich histones of chicken liver were studied in order to see whether a protein similar to mammalian histone H1o was present in this lower vertebrate. The following biochemical methods were used: sodium dodecylsulphate and acid-urea electrophoresis, gel exclusion chromatography on BioGel P100, and ion-exchange chromatography on BioRex 70. Specific polyclonal antibodies were elicited against purified mouse liver H1o and chicken erythrocyte H5, and applied for the further characterization of the chicken H1 subfractions obtained chromatographically. The results from microcomplement fixation and enzyme-linked immunosorbent assays showed that the presumptive chicken liver H1o shared common antigenic determinants with the mammalian H1o and the chicken liver H5. Based on the combined biochemical and immunological evidence, we conclude that an H1o-like protein is present in quiescent differentiated avian cells. The data of Smith et al. [34], who did not find this specific lysine-rich histone in resting chicken cells, are discussed.

[Immunochemical analysis of histone H1 and H5 from pigeon erythroid cells]. / Immunokhimicheskoe issledovanie gistonov H1 i H5 iz eritroidnykh kletok golubia.

An antiserum with the antibody titer of 1 : 4096 was obtained by immunization of rabbits with the tRNA-histone H5 complex from pigeon erythrocytes. The specificity of the antiserum was studied quantitatively from the reaction of the complement binding to a homologous antigen (histone H5) and its modifications (I, II, III), differing in the degree of phosphorylation. It was shown that phosphorylation of histone H5 increases the ability of the antigen to bind to antibodies, which is especially well-pronounced at the antiserum dilutions as high as 20480. The comparison of the antigenic properties of histones H5 from pigeon and chicken erythrocytes revealed beside structural differences of the proteins the presence of common antigenic determinants. A similar observation was made when histones H5 and H1 from pigeon erythrocytes were compared. Histone H1 from chicken erythrocytes and histone H1 from calf thymus did not produce criss-cross reactions with antiserum H5.

Existence of differences in repressor properties between serine-rich histones (H5, F2c) from immature and mature pigeon erythroid cells.

The abilities of H1 and H5 histones from immature and mature pigeon erythroid cells and subfractions of H5 histones with different content of alkali-labile phosphorus to restrict RNA synthesis were compared in an in vitro transcription system with bacterial RNA polymerase. It has been found that: a) H1 histones from both sources exhibit similar efficiency. b) H5 histones from immature cells restrict transcription to a lesser extent than the same histone from the mature erythrocyte. c) The subfraction of H5 histone from immature cells with the higher content of alkali-labile phosphorus restrict transcription less than the subfraction with the lower degree of phosphorylation. The results suggest that H5 histone, which first appears in the erythroblasts in a highly phosphorylated form, does not display its potential 'repressor' properties. During erythrocyte maturation H5 histone is dephosphorylated and this causes the massive inactivation of erythrocyte genome.

[Role of serine-rich histone (H5) in bird erythrocyte genome inactivation]. / Rol'gistona, bogatogo serinom (H5), v inaktivatsii genoma éritrotsitov ptits.

The ability of H5 and H1 histones, purified from immature or mature pigeon erythroid cells, to suppress RNA synthesis in vitro was compared. It was found that H1 histones from both sources as well as histone H5 from bone marrow suppress RNA synthesis to a comparable degree while H5 from the mature erythrocytes exhibits significantly higher suppression efficiency. H5 histone subfractions, differing in phosphate content, also had different ability to restrict the template activity of chromatin: the higher is the phosphorylation level of H5 histone, the weaker is its effect on the transcription.

In vitro transcription of partially deproteinised and reconstituted chromatins from pigeon erythroid cells.

The role of protein fractions extracted from chromatin preparations with NaCl concentrations up to 0.7 M in the additional repression of pigeon erythrocyte genome was investigated. The chromatins from erythroblasts and erythrocytes were dissociated with 0.7 M NaCl and reconstituted from dissociated components to obtain the "original" and "hybrid" chromatins. The protein fraction extracted from erythrocyte chromatin at 0.7 M NaCl was more efficient in the restriction of transcription with partially deproteinised chromatin from both erythroblasts and erythrocytes. The partially deproteinised chromatin from both erythorblasts and erythrocytes. The partially deproteinised chromatins were also complexed in various conditions with purified F1 or F2c histones. In such complexes, F2c histone was a stronger inhibitor of template activity than histone F1.

The role of kinetocardiography in the complex study of the mechanical cardiac activity in ischemic heart disease.

The complex study of mechanical manifestations of cardiac activity by kinetocardiography, along with a complete clinical examination, is suggested as a rather sensitive method which precisely detects the changes of cardiodynamics in disturbances of the coronary circulation, rendering information useful in diagnosis and prognosis.