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Biomedical subjects

Iu F Bogdanov

Publications and source records attributed to Iu F Bogdanov.

16 recordsLinked to original sources
PubMed1993

[Synaptonemal complexes of chromosomes of male mice after prolonged administration of neoaquasept].

A long-term (during 4 months) daily peroral injections of neoaquasept (NA) (a drinking water disinfections agent) at a dose corresponding to the normal level of consumption increases the number of spermatocytes in which the sexual bivalent associates with normal autosomal bivalents (up to 18.2%). In single cells a premature desynapsis of sex chromosomes at late pachytene was observed. There was the appearance of single cells with the X0 karyotype. A 3-fold excess of the normal consumption of NA causes an increase in the number of cells with the above disturbance in the SC structure and behaviour and causes the appearance of heteromorphic bivalents. On the 7th day after a single MTD injection of NA male mice displayed a sharp (up to 27.9%) increase in the number of cells in which the sexual bivalent associated with autosomal bivalents, formation of univalents of autosomal and sex chromosomes, SC degeneration.

Adolescent↗
PubMed1993

[A preparative method for isolating the synaptonemal complexes from mammalian spermatocytes].

A method of isolation of synaptonemal complexes (SC) from mouse, rat and Syrian hamster spermatocytes is described. A fraction of pachytene spermatocyte nuclei was obtained by centrifugation of the testis homogenate in stepwise sucrose gradient and then lysed. The resulting chromatine was hydrolysed with DNAse II, and a fraction of isolated SCs was obtained by ultracentrifugation of the hydrolysate. The method can be applied for obtaining the SC fraction from spermatocytes sufficient for cytological, biochemical and molecular biology studies.

Animals↗
PubMed1991

[Ectopic interactions of Drosophila melanogaster polytene chromosomes in the H-E system of hybrid dysgenesis].

Analysis of salivary gland polytene chromosomes of Drosophila melanogaster age III larvae has demonstrated that inversions make up high percentage of aberrations induced by transposition of the hobo element. The frequency of inversions increases upon irradiation. In view of the fact that transpositions of mobile elements and irradiation can considerably affect the homology of associating regions, ectopic chromosome contacts were analysed. On the one hand, this analysis has revealed general features for all types of crosses, such as the prevalence of intrachromosomal contacts over interchromosomal ones, predominant localization of both types of contacts in telomeric regions of chromosomes and lower frequency of their occurrence on X chromosome in males as compared with females. On the other hand, the specificity of ectopic conjugation in different types of crosses has been determined. Given a constant average frequency of ectopic contacts in the D. melanogaster genome, differences in their distribution in chromosomes have been detected. Chromosomes of pure lines differ from their homologues in dysgenic hybrids by distribution of ectopic conjugation peaks and by localization of a number of unique events. On the basis of our own experiments and literature data, the role of ectopic contacts as structural formations connecting chromosome regions similar in their functional activity, rather than in nucleic-protein characteristics, is discussed.

Animals↗
PubMed1990

[Effects of gamma-irradiation on the gonadal cells of Drosophila melanogaster under varying conditions of hybrid dysgenesis].

Comparative analysis was carried out with respect to the results of combined effects of gamma-irradiation and transposition of mobile elements in Drosophila, depending on the succession of their application. As turned out, introduction of the P and hobo elements into the M' line, prior to irradiation, resulted in decreased number of unfertilized eggs and reduced the proportion of flies killed at the larval and pupal stages. However, opposite effects were shown, when the P element was introduced following irradiation: the number of unfertilized eggs and that of the flies killed at the larval and pupal stages has significantly increased, as compared to the control. Interaction between the processes induced at the level of DNA repair both by gamma-irradiation and the P' elements' transposition is suggested.

Animals↗
PubMed1990

[Synaptonemal complexes of the A- and B-chromosomes of the spermatocytes from the East Asian mouse Apodemus peninsulae].

The analysis of whole-mount preparations of synaptonemal complexes (SCs) from surface-spread spermatocytes of A. peninsulae (2n = 48A + 1, 2, ... 12 B) had revealed SCs of 23 autosomal bivalents, sex bivalent XY, axial cores and SCs of the B-chromosomes. The intercellular and interindividual variability of the number of B-chromosomes varied from 1 to 12 per cell. The SCs of autosomal bivalents were shown to have a typical structure. The structure and behaviour of SCs of sex bivalent throughout meiotic prophase I appeared to be similar to those observed in other species of this order. Mainly B-univalents and less frequently B-bivalents containing SCs were found to be formed in meiotic prophase I. The full homologues appear to be rarely seen among B-chromosomes of the East-Asiatic mouse. A tendency of forming clusters of B-univalents near the sex bivalent was found, in addition to B-bivalents with lateral elements, having the form of bi- and tri-stranded elements with rare synaptic fragments. Besides this, the SCs of the autosomes of pachytene cells were found to contain structures resembling the recombination nodules.

Animals↗
PubMed1988

[Association between synaptonemal complexes of sex and autosomal bivalents in male tx/ty mice as a possible cause of their sterility].

Electron microscopic study of total preparations of synaptonemal complexes of spermatocytes I from sterile heterozygous male mice--t12/tw18; tw5/twPa-1; twPa-1/tw18 was performed. T/tw18 and C3H/N fertile heterozygotes were used in each variant as control. The cells are karyotyped in all experiments, as based on the measurements of the length of 19 SC autosomes and SC sex complex. All sterile compounds (spermatocytes) demonstrate high frequency of different types of associations (72%) between sex chromosomes and the autosome 17 carrying a chromosomal aberration in the region of the T-locus. The heterozygotes tx/ty used in our experiments show no disruption of chromosome synapsis, when even studied under electron microscope, though some atypical changes in the ultrastructure of chromosome axes and frequent atypical associations of the axes of XY-sex bivalents in sterile heterozygous animals exist.

Alleles↗
PubMed1988

[Identification of aberrant chromosomes based on the morphometry of the synaptonemal complexes in a sterile male mouse].

The synaptonemal complexes (SCs) of surface-spread spermatocytes of male mouse from the F1 progeny of a male exposed to a mutagen have been examined by electron microscopy. Nonreciprocal translocation was recognised in analysing configuration of SC. Electron microscope analysis revealed translocation in 100% pachytene spermatocytes and light microscope analysis of air-dried metaphase spermatocytes demonstrated this in 58% cells. Different types of association of X-chromosome with aberrant chromosomes were discovered in pachytene spermatocytes. Computer analysis of relative length of SCs permits to detect a nonreciprocal translocation from chromosome 4 to chromosome 16. The length of the translocated fragment was determined to be from 66 to 75% of the length of chromosome 4. It has been impossible to discover a telomere fragment of chromosome 16, because the break point of chromosome 16 is too close to the distal end.

Animals↗
PubMed1986

[Analysis of chromosome aberrations on the basis of synaptonemal complexes in the offspring of mice irradiated with gamma-rays].

Electron-microscopic analysis of synaptonemal complexes (SC) spread on the surface of hypophase was carried out to study chromosome rearrangements in sterile and semisterile F1 offsprings of mice exposed to gamma-radiation at a dose of 5 Gy. Chromosome rearrangements were microscopically scored at diakinesis - metaphase I in the same animals. SC analysis at pachytene revealed chromosome rearrangements in 63% spermatocytes. Analysis of chromosomes at diakinesis - metaphase I in the same animals only revealed chromosome rearrangements in 32% cells. SC analysis permits detecting chromosome rearrangements undetectable at diakinesis - metaphase I.

Animals↗
PubMed1985

[Biochemical and ultrastructural analyses of the synaptonemal complex in mammalian spermatocytes].

In order to study the molecular organization of synaptonemal complex (SC), a preparative method for isolation of relatively purified SC from rat, mouse and hamster testes was elaborated which involves isolation of SC-containing (pachytene) nuclei, their lysis, DNAase digestion of DNA and fractionation of nuclear elements by the discontinuous sucrose density gradient centrifugation. Electron microscopy revealed a rather good preservation of the SC structure after the isolation procedure. Effects of the dissociating agents on the SC structural integrity were studied. It has been demonstrated that the treatment with 2M NaCl, Triton X-100, sodium deoxycholate, 6M urea, and with a buffer containing 2% SDS and 5% mercaptoetthanol does not lead to a complete SC dissociation, though it results in some structural chanes. Possible reasons of the high resistance of SC to dissociating treatment are discussed.

Animals↗
PubMedDate not supplied

[Various properties of DNA from isolated fractions of the mouse synaptonemal complexes].

A fraction of synaptonemal complexes (SC) isolated from mouse spermatocytes has been electrophoretically purified in agarose gel. The DNA from the SC fraction constitutes approximately 0.5% of total nuclear DNA, and its molecules have length heterogeneity from 1 k.b. to 20 k.b. The content of beta-globin gene is the same in DNA from the SC fraction and in total nuclear DNA. The specificity of DNA from the SC fraction is manifested by higher contents of the repeated alternative sequences GT/CA and B1-sequence that is probably due to the processes of genetic meiotic recombination.

Animals↗
PubMedDate not supplied

[Features of the primary structure of DNA from the synaptonemal complex of the golden hamster].

DNA of golden hamster synaptonemal complex (SC) was cloned and partially sequenced. Computer analysis was performed to compare the SC DNA sequences for different families of eukaryotic genomic DNA. SC DNA is homologous to LINE family and in contrast to genomic DNA is enriched with alternative (GT/CA)n sequences and palindromes. By its ability to form potential hairpin loops, SC DNA is similar to nuclear matrix-associated regions of DNA (MARs) and differs considerably from DNA of microsatellite loci. It is noteworthy that SC DNA, which is supposed to be involved in meiotic recombination, and DNA of immunoglobulin genes, involved in somatic recombination, are both enriched with palindromes. The discovered peculiarities of the structure of hamster SC DNA allow us to join it with rat SC DNA into a special family of rodent genomic DNA sequences.

Animals↗