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L F Nazarova

Publications and source records attributed to L F Nazarova.

At least 19 recordsLinked to original sources
PubMed1990

Comparison of the spectra of proteins synthesized in mouse thymocytes after irradiation or hydrocortisone treatment.

The proteins synthesized in mouse thymocytes after irradiation and hydrocortisone treatment were analyzed by two-dimensional electrophoresis. An exposure to lympholytic agents induced different changes in the biosynthesis of proteins; however the induction of a few common proteins by these agents was revealed. The increase in the synthesis of five nuclear polypeptides occurred at early times (15-75 min) after irradiation. At least two of them (proteins of the nuclear matrix) are also induced by hydrocortisone. Synthesis of three of these 'early proteins' soon terminated, while the synthesis of the other two increased, and by 3.5 h they were found in large quantities after both treatments. At the same time, another protein common for both agents was induced. Three of these nuclear proteins are part of the nuclear matrix. Participation of these proteins in realization of the cell death program is discussed.

Animals↗
PubMed1984

Chromatin regions, released by endogenous nucleases, are enriched in immunogenic tissue-specific proteins.

Localization of immunogenic tissue-specific proteins in chromatin regions, hypersensitive to endogenous nucleases, has been studied using rabbit antibodies against rat thymus chromatin. It is shown that the first 1-2,5% of the chromatin (calculating on DNA), released by Mg2+-, Mn2+- and Ca2+/Mg2+-dependent nuclear endonucleases are drastically enriched in tissue-specific antigenic determinants. The released chromatin fractions are found to contain a heterogeneous set of nonhistone proteins and are deficient in histones. The cleavage of nuclear DNA by endogenous acidic nuclease, independent on bivalent ions, resulted in a significantly less enrichment of the released fractions with immunogenic proteins.

Animals↗
PubMed1984

[Immunogenic, tissue-specific, antigenic determinants of thymocyte chromatin--firmly bound to nonhistone proteins].

Rat thymocyte chromatin was dissolved in 1.0 or 2.0 M NaCl and the dissociated proteins were separated by ultracentrifugation or gel filtration on Sephadex G-200. Rabbit antibodies against tissue-specific antigenic determinants of thymus chromatin interact with "depleted" deoxynucleoproteins and not with dissociating proteins. The DNA complex with firmly bound proteins obtained in 2 M NaCl was treated with DNAase I; this treatment had no effect on proteins interaction with antibodies. Thus, tissue-specific antigenic determinants can be related to the most firmly bound nonhistone proteins.

Animals↗
PubMed1982

[Immunoluminescent analysis of the tissue specificity of chromatin proteins].

Rabbit antibodies against the rat thymus chromatin were obtained. The interaction of IgG purified from antisera and of their Fab-fragments with the rat thymocyte and hepatocyte nuclei was studied by indirect immunofluorescence. Antibodies preincubated with the rat liver chromatin did not react with hepatocyte nuclei but interacted with thymus nuclei. Thus, at least part of antigenic determinates of the rat thymus chromatin is tissue-specific.

Animals↗
PubMed1981

[Changes in the accessibility of chromatin antigenic determinants induced by different influences].

The accessibility of protein antigenic determinants of rat thymocyte chromatin was studied in a reaction of complement fixation, using antisera from animals immunized with chromatin or non-histone proteins and control sera containing natural antichromatin IgG. It was shown that the bulk of the antigenic determinants of intact chromatin are inaccessible for antibodies. The reactivity of chromatin in the complement fixation assay increases after ultrasonication or irradiation in vitro as well as the enzymatic cleavage of chromatin down to nucleosomes and their oligomers in dying thymocytes in vivo. This effect can mainly be due to changes of chromatin compactization.

Animals↗
PubMed1981

[Isolation and characterization of antibodies against chromatin and non-histone proteins from rat thymocytes].

The antisera of rabbits immunized with chromatin and non-histone proteins (NHP) were compared to natural antibodies against chromatin. It was shown that in indirect immunofluorescence and complement fixation assay the immune and control sera interact with chromatin at close dilutions. The IgG purified from the immune sera which do not bind to DEAE-cellulose interact with chromatin at concentrations that are 10-20 times less than that of the corresponding fraction of IgG from intact rabbit serum. The same correlation was observed for the Fab-fragments obtained from immune and control sera IgG. The IgG prepared from the sera of immunized and intact rabbits and eluted from a DEAE-cellulose column with approximately 0.15 M Na-phosphate buffer interact with chromatin at approximately equal concentrations. All the sera tested and the IgG prepared from them interact with NHP but not with DNA and histones, the antibody spectra of immune and control sera being different. It may thus be concluded that intact rabbit sera contain natural antibodies against NHP. Immunization by chromatin or NHP results in generation of antibodies against other fractions of NHP.

Animals↗
PubMed1981

[Detection of IgG fraction of intact rabbit serum interacting with chromatin].

It was shown that the intact rabbit sera interact with chromatin and thymocyte nuclei in a quantitative reaction of complement fixation and immunoluminescence analysis, respectively. Purified immunoglobulins G (IgG) and Fab fragments isolated from them were also found capable of such interactions. The interactions are not caused by Ig aggregate absorption on chromatin and can be due to the presence of natural antibodies against chromatin in the 7S fraction of intact rabbit IgG. These IgG possess heterogeneous charges, presumable due to the presence of antibodies against various antigenic chromatin determinants in rabbit serum.

Animals↗
PubMed1975

[Presence of biologically active glutamyl peptide in rabbit bone marrow].

The presence of chromatographically pure and biologically active glutamylpeptide in the rabbit bone marrow was shown and methods of its isolation were given. The substances had an unusual circular dichroism contrary to that of the natural proteins. In a concentration of 10(-5) M the isolated peptide decreased the survival of the Chinese hamster culture cells to 30%. It was analogous to the peptide isolated formerly from plants by a number of physical and chemical characteristics; the latter possessed cytogenetic activity and increased the mutagenic action of the ionizing radiation.

Animals↗
PubMedDate not supplied

[Early changes in the biosynthesis of proteins in the thymocytes of mice following exposure to lympholytic agents].

The method of two-dimensional electrophoresis was used to study protein biosynthesis in cytoplasm, nuclei and nuclear matrix of mouse thymocytes 15-75 min after exposure to ionizing radiation and hydrocortisone. Irradiation was shown to inhibit some cytoplasm proteins and to induce synthesis of a few polypeptides within the total nuclear proteins and nuclear matrix. Hydrocortisone promotes synthesis of some new proteins in all the fractions leading to the formation of new polypeptides. At least one common peptide is found within the total nuclear proteins and nuclear matrix after the effect of both factors.

Animals↗
PubMedDate not supplied

[Changes in the biosynthesis of nuclear proteins in the thymocytes of mice exposed to radiation and hydrocortisone].

Biosynthesis of nuclear proteins of mouse thymocytes affected by gamma-radiation and hydrocortisone was studied using two-dimensional electrophoresis. The two lympholytic agents were shown both to inhibit and to induce certain protein synthesis. The appearance of the same polypeptides after exposure to radiation and hydrocortisone indicated that these proteins possibly contribute to the implementation of the cell death programme.

Animals↗
PubMedDate not supplied

[Postirradiation changes in the chromatin structure of thymocytes in irradiated rats].

In this work the antibodies were obtained against chromatin isolated from thymocytes of intact and irradiated rats (2 h after exposing to 10 Gy) and against polydeoxyribonucleotides (PDN) extracted from thymus nuclei 6 h following irradiation. All the antibodies under study reacted more readily with the chromatin obtained from the thymus of exposed rats than with the control chromatin. The complexes of DNA with the most firmly bound non-histone proteins, obtained from the three objects under study, reacted with the antibodies with equal efficiency. Thus, a higher reactivity of PDN and chromatin from thymocytes of exposed rats was associated with the decondensation of the latter leading to an increase in availability of a part of antigenic determinants. Using the immunoblotting method we failed to discover any qualitative differences in the protein composition of the chromatin from control and exposed rats.

Animals↗
PubMedDate not supplied

[Immunochemical analysis of changes in the structure of the nuclear matrix in thymocytes of irradiated rats].

It was shown that reactivity of the nuclear matrix of thymocytes for antibodies against chromatin of the control and irradiated thymocytes and PDN did not change immediately and increased markedly 2 h following irradiation of rats with a dose of 10 Gy. The method of immunoblotting failed to reveal any qualitative differences in the protein content of the thymocyte nuclear matrix of the control and exposed rats.

Animals↗