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Biomedical subjects

S N Khil'ko

Publications and source records attributed to S N Khil'ko.

At least 19 recordsLinked to original sources
PubMed1992

[An electrophoretic analysis of human glycoprotein hormones and their subunits].

Stability of heterodimers of human glycoprotein hormones with gonadotropic and thyrotropic activities in sodium dodecylsulfate (SDS) under non-reducing conditions at low temperature permits to resolve the native molecules of these hormones in SDS-PAG and to distinguish from their dissociated subunits by electrophoretical mobility. The analysis of dimers and alpha-, beta-subunits in one polyacrylamide gel allows to detect certain human glycoprotein hormones and to study some of their physico-chemical properties. Using two polyclonal antisera against human LH and FSH by the Western blot immunoassay it was shown that heterodimers as well as alpha and beta subunits after SDS-PAGE retain antigenic activity of native hormones. The method gave possibility to characterize the specificity of the given sera to different glycoprotein hormones.

Animals↗
PubMed1990

[Purification and properties of the hexon antigen of canine adenovirus serotype CAV-1].

The main antigen and immunogen of canine adenovirus type 1 (CAV-1) has been purified to near homogeneity from cultural fluid of a CAV-1-infected primary cell culture by hydrophobic and anion-exchange chromatography. The hexon native form (trimer) was shown to be resistant against denaturation by SDS under conditions of SDS-PAGE performed without heating the samples. The monomer chain of the CAV-1 hexon was apparently identical in terms of electrophoretic mobility with that of the previously sequenced BAV-3 hexon polypeptide (103 kDA). In blot enzyme immunoassay only native trimers of CAV-1 hexon were detected by cross-specific polyclonal and monoclonal anti-hexon antibodies.

Adenoviridae↗
PubMed1989

[Immunoenzyme analysis of adenovirus hexons. Indication and characteristics of rabbit and mouse antibodies against hexons].

An enzyme-linked immunosorbent assay (ELISA) was developed for analysis of rabbit and mouse IgG antibodies specific to adenoviral hexon. The anti-hexon antibodies were detected by capture with purified hexon coated onto polystyrene microtiter plates and visualizing them by respective anti-IgG horseradish peroxidase conjugates. In the sera from hyperimmunized rabbits and mice as well as in the mouse ascite fluids the ELISA procedure revealed primarily type-specific (epsilon) and genus-specific (alpha) antigenic determinants in hexon but not those of intermediate specificities.

Adenoviridae↗
PubMed1989

[Immunoenzyme analysis of adenovirus hexon. Determination of antibodies from hyperimmunized chickens].

We have elaborated three systems of enzyme-linked immunosorbent assay (ELISA) for detection of chicken IgG antibodies specific for hexon antigens of three immunologically distinct adenovirus groups: those of mammalian adenoviruses (Mastadenovira), typical avian adenoviruses (Aviadenovira) and of egg-drop syndrome-76 (EDS-76) virus. In each system the antibodies against respective hexons were specifically detected. In mammalian adenovirus hexons the ELISA detects primarily the type-specific (epsilon) and genus-specific (alpha) antigenic determinants. The time course of anti-hexon antibodies content was followed during immunization. The level of anti-hexon antibodies in egg yolk reflects adequately their content in blood serum. The technique is suitable for serological diagnosis of chicken adenoviral infections as well as for characterization of egg-yolk antibodies obtained by preparative hyperimmunization of hens.

Adenoviridae↗
PubMed1986

[Stability of the structure and antigenic determinants of adenovirus type 1 native hexon to proteases].

Hexon capsomers of human adenovirus type 1 (h1) labeled by iodine 125 were digested in a native state (trimers) by trypsin, chymotrypsin or papain, and the resulting hydrolysates were analyzed by SDS-PAGE. In each case, a discrete and temporally stable pattern of relatively large fragments was revealed. The degree of hexon polypeptide hydrolysis was maximal for papain, intermediate for chymotrypsin and minimal for trypsin, the largest fragments in the digest being 32, 40 and 80 kD, respectively. At room temperature, all the electrophoretically discernible hexon proteolytical fragments were held together in structures resembling intact hexon trimers and could be regarded as "hexon cores", of which papain hexon cores were the most stable during SDS-PAGE. Radioimmunoprecipitation analysis revealed a complete absence of native hexon antigenicity in thermodenaturated fragments of hexon protease digests, while native trypsin, chymotrypsin and papain hexon cores could be precipitated by hexon-specific antibodies. The immunoprecipitated material contained all of the hexon fragments found in appropriate hexon cores and retained the structure of the original cores. Trypsin, chymotrypsin and papain hexon cores were shown to possess at least part of native Ad h1 hexon antigenic determinants of each of the following specificities: species-specific (epsilon), cross-reactive with hexon of human adenoviruses (h3 and h6), simian adenovirus (sim 16), bovine adenoviruses (bos 3 and bos 7) and avian adenovirus (Aviadenovirus gal 1 or CELO). Thus, the full spectrum of known hexon antigenic determinants (species-specific to intergenus-crossreactive) is at least portly stable against protease attack of native hexon capsomers.

Adenoviruses, Human↗
PubMed1985

[Electrophoretic purification of biologically active structural proteins of the simian adenovirus SA7 in the presence of sodium dodecyl sulfate].

The modification of disc electrophoresis technique in polyacrylamide gel with sodium dodecylsulphate (SDS) has been elaborated for synchronous isolation of some structural proteins in biologically active form and in preparative quantities from adenoviruses. Virions of SA7 adenovirus were mildly dissociated in SDS solution at 20 degrees C and structural proteins were stained by fluorescamin. After separation the zones of proteins corresponding to the native capsomeres of hexon and protein IV as well as the zones of inner proteins V and VII have been identified as fluorescent at UV-irradiation, excised and extracted by SDS solution. After the removal of SDS by protein precipitation in acetone the preparations of hexon and IV reveal the quaternary structure of native capsomers and full spectrum of antigenic and immunogenic activities of native proteins. Preparations of inner proteins V and VII possess activity in condensing adenoviral DNA. The technique is usable for preparative purification of inner polypeptide VI SA7, as well as capsomers and inner proteins of other adenoviruses.

Adenoviridae↗
PubMed1985

[Conditions of stability for the quaternary structure and antigenic activity of adenovirus hexon].

The procedure of SDS-PAGE was modified by lowering the temperature of protein sample dissociation to allow the separation of denaturated adenoviral hexon chains and native hexon capsomers (trimers) in the same gel. By combining the modified SDS-PAGE with dot and blot radioimmunoassays, the range of stability of the simian adenovirus SA7 hexon quaternary structure and its antigenicity was studied against a number of physical and chemical agents known to dissociate and denaturate proteins. A perfect correlation was found between the hexon native quaternary structure (trimer) and its immunoreactivity with anti-hexon immunoglobulins. The pattern of hexon trimer stability to a wide spectrum of denaturants suggests that its subunits are held together, mainly by hydrophobic interactions, in such a way that the innersubunit contact regions make up the "hydrophobic core" of the hexon molecule.

Adenoviridae↗
PubMed1983

[Determination of the species specificity of interferons in the translation of the their mRNA from various cell cultures].

Interferons obtained on induction of human lymphocytes with Newcastle viruses and staphylococcal enterotoxin A and diploid fibroblast cells of human embryos with poly (I).poly (C), as well as translation products of interferon mRNA obtained from these cells were analysed serologically. It was shown that the main type of interferon produced by the cells depended on the cell culture and inductor nature. It was defined at the level of the respective gene depression. Effective translation of mRNA of the interferons of the 3 types makes possible production of cDNA and creation of bacterial plasmids coding the genetic information for the synthesis of human interferon.

Cells, Cultured↗
PubMed1983

[Purification and identification of mRNA of immune (gamma) interferon from human splenocytes].

The isolation of total RNA from primary culture of human splenocytes and its physico-chemical and biological properties are described. Human splenocytes are characterized by a high content of mRNA of human immune interferon, low content of total RNA and an extremely high activity of RNAases. Therefore it was necessary to elaborate conditions for the isolation of mRNA without DNA contaminants in the presence of extensive inhibitors of the RNAase activity. These include cell homogenization, separation of cytoplasm at -10 degrees C and treatment by RNAase inhibitors--ribonucleoside-vanadyl complexes or a combination of aurin-tricarboxylic acid with dithiothreitol. The resulting preparations of total RNA were purified by chromatography on oligo (dT)-cellulose and translated in a cell-free system from rabbit reticulocytes. These preparations were free of nonspecific translation inhibitors which are normally present in the lymphoid cells mRNA. In a cell-free system mRNA of human splenocytes induced with staphylococcal enterotoxin A code the synthesis of biologically active interferon which was identified as immune (gamma) human interferon, using a serological analysis. The preparations of immune interferon mRNA obtained under the conditions described above can further be used for cloning of the corresponding gene in bacterial cells.

Chromatography, Affinity↗
PubMed1982

[Use of affinity chromatography for the purification of specific endonuclease Eco RI and Bg1 II].

The highly active preparations of specific endonucleases Eco RI and Bgl II were purified by affinity chromatography from E. coli and Bacillus globiggii cells, respectively. The isolation and purification procedures included cell disruption by ultrasonication, ultracentrifugation and chromatography. Blue dextrane-Sepharose, folate-Sepharose and phenyl-Sepharose were used as affinity adsorbents. The optimal conditions for the adsorption and elution of the endonucleases excluding intermediate steps of dialysis and concentration were selected. A high degree of purification was achieved by a consecutive use of adsorbents with different ligands. The purified enzyme does not contain non-specific nucleases or phosphatases, is sufficiently concentrated and can be used for specific hydrolysis of DNA.

Bacillus↗
PubMed1981

[Expression of plasmid R6K in a cell-free coupled transcription-translation system].

The modified method for obtaining E. coli extract S 30 for the coupled transcription--translation system is described. The extract treated with immobilized DNAase and micrococcal nuclease had the minimal endogenous protein synthesis and high activity in respect to exogenous DNA matrices. The synthesis of 9-12 proteins with molecular weights ranging from 14,000 to 178,000 daltons was shown to occur in this system in the presence of the DNA of R6K plasmid. The use of the modification of Novick's method allowed to identify active beta-lactamase coded by the amp-gene of R6K plasmid.

Cell-Free System↗
PubMed1979

[Inhibitory effect of 18S-rRNA from mouse reticulocytes on translation of exogenous and endogenous mRNA in a cell-free system of wheat embryos].

The effect of 18S-rRNA from mouse reticulocytes on the translation of exogenous and endogenous matrices in a system of wheat embryos was studied. It was found that after addition of 18S-rRNA the translation of exogenous and endogenous mRNAs is strongly inhibited. Treatment of 18S-rRNA with proteinase K prior to the addition did not remove the inhibiting action of rRNA. A RNA hydrolysis by alkali resulted in a considerable decrease of the inhibitory effect.

Animals↗
PubMed1977

[Application of nitrocellulose Nitrocell S for preparation of mouse globin mRNA].

Two methods of chromatography were applied and compared to purify individual mRNA for mouse globin. In one case commercial product Nitrocell S was used, in another affinity chromatography on oligo-dT-cellulose was applied. Translation of purified mRNA was performed in the heterological wheat germ system in vitro. Products of translation were identified as alpha- and beta-chains of mouse globin. The data obtained permits us to recommend Nitrocell S as efficient and cheap chromatographic material for purifing poly-A-containing RNA.

Animals↗