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S Ia Dadashev

Publications and source records attributed to S Ia Dadashev.

18 recordsLinked to original sources
PubMed2005

[Developing and testing a method of in silico identification and characterization of meiotic DNA].

A method of in silico search for specific repetitive DNA sequences related to the synaptonemal complex (meiDNA) in mammalian genomes was developed. A study of the distribution of these repeats over chromosomes revealed their scarcity on the Y chromosome and a decrease in recombination frequency in regions enriched in meiDNA. The results are discussed in context of the model of the looplike meiotic chromosome organization during the formation of the synaptonemal complex.

DNA↗
PubMed2005

[In silico identification and characterization of meiotic DNA: AluJb possibly participates in the attachment of chromatin loops to synaptonemal complex].

Earlier, using bioinformatic methods, we reported the identification of repeated DNA sequences (RS), presumably responsible for the attachment of chromatin loops to the lateral elements of synaptonemal complex in meiotic chromosomes. In the present study, consensus sequences for this class of RS were identified. It was demonstrated that at least part of these sequences belonged to the AluJb subfamily of Alu sequences. The Alu copies distribution along the major human histocompatibility complex (MHC) and their spatial separation from the sites of meiotic recombination was examined. It was demonstrated that simple sequences, like (GC/CA)n, were flanking meiotic recombination sites. A model of the RS organization in meiotic chromosome, most efficiently linking experimental data on the meiotic recombination in MHC and the in silico data on the RS localization (the coefficient of multiple correlation, r = 0.92) is suggested.

Alu Elements↗
PubMed2003

[On the question of using alleles of gliadin-coding loci as possible markers of adaptive ability in cultivars of spring wheat (Triticum aestivum L.) during seed germination].

Prolamine proteolysis is assumed to be among numerous adaptability factors in cereals. The patterns of gliadin proteolysis have been studied in 16 cultivars of spring wheat via analysis of electrophoretic spectra. Four proteolytic patterns have been identified. It is hypothesized that the cultivars characterized by early and rapid proteolysis (the first and third types) are the most adaptable. The gliadin genetic formulas of chromosomes of the first homeologous group have been determined. The alleles of gliadin loci (Gli-Alf, Gli-Ble, Gli-D1a, and Gli-D1b) have been found that can be used as markers of adaptability in spring wheat cultivars.

Adaptation, Physiological↗
PubMed2002

[CG17604 gene from Drosophila melanogaster--possible functional homolog of the yeast ZIP1 and SCP1 (SYCP1) mammalian genes, coding for synaptonemal complex proteins].

From data on the molecular organization of transverse filament proteins of the synaptonemal complex (SC)--Zip1 in yeast and SCP1 in mammals--and on the width of the central SC space in these organisms and in Drosophila, the putative molecular structure and size of a transverse filament protein of the SC in Drosophila has been inferred. Using genetic and molecular databases and software from the Internet, we carried out in silico screening for a candidate gene for the Drosophila transverse filament protein. The search in the 250-bp region overlapping the locus of this gene (sections 88E-89B) and containing 78 predicted genes has revealed only one gene, CG17604, whose protein meets all requirements for the transverse filament protein of the SC. It was suggested that gene CG17604 is gene c(3)G. In this case, gene c(3)G must be localized in section 89A7-8 of the cytological map of Drosophila melanogaster.

Animals↗
PubMed2002

[Comparative genomics and proteomics of Drosophila, Brenner's nematode, and Arabidopsis: identification of functionally similar genes and proteins of meiotic chromosome synapsis].

The published principles of computer analysis of genomes and protein sets in taxonomically distant eukaryotes are expounded. The authors developed a search strategy to identify in genomes of such organisms genes and proteins nonhomologous in primary structure but having similar functions in cells dividing by meiosis. This strategy based on the combined principles of genomics, proteomics, and morphometric analysis of subcellular structures was applied to a computer search for genes encoding the proteins of synaptonemal complexes in genomes of Drosophila melanogaster, the nematode Caenorhabditis elegans, and the plant Arabidopsis thaliana. These proteins proved to be functionally similar to their counterparts in yeast Saccharomyces cerevisiae (protein Zip1p) and mammals (protein SCP1).

Animals↗
PubMed2001

[Damaging effect of antibiotics on the structure of synaptonemal complexes of meiotic chromosome of mice].

The structure of synaptonemal complexes (SCs) of chromosomes of mouse primary spermatocytes were studied using electron microscopy on days 1, 10, and 36 after the completion of per os administration of drugs belonging to three groups of antibiotics: tetracyclins, macrolides, and fluoroquinolones. The antibiotics were administered to mice during ten days. At the substages of early and middle pachytene, heteromorphic SC bivalents and fragments of chromosome-core elements were detected in spermatocytes at all times studied after the administration of the antibiotics of three groups. As cells passed through the period from early to middle pachytene, the number of cells containing heteromorphic SC bivalents and the fragments of chromosome cores gradually decreased, which could be an indication of selection of cells with chromosomal aberrations. A high level of associations between the X chromosome and autosome bivalents (including heteromorphic ones) also favors this suggestion. A gradual decrease in the number of chromosomal aberrations was detected, as time elapsed from the completion of antibiotics administration. The study of sperm obtained from epididymises of males did not reveal significant differences in both morphology and motility of sperm between males of the control and experimental groups.

Animals↗
PubMed2001

[Use of artificial neuronal nets in automation of analysis and genetic identification of electrophoretic spectra of gliadin from durum wheat].

Each wheat cultivar has a characteristic spectrum of gliadins. This makes it possible to use blocks of the components of reserve proteins as genetic markers when estimating seed quality. However, identification of the blocks that constitute the electrophoretic spectrum is a complicated task. For this purpose artificial neural network (ANN) technology is proposed. Based on experimental data, a teaching database and testing databases have been created. ANN was shown to be highly efficient (efficiency up to 100%) expert system for deciphering the electrophoretic spectra of gliadins of durum wheat cultivars.

Automation↗
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↗
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↗
PubMed1984

[Isolation and purification of bacterial ribosomes from endotoxin using polyethylene glycol].

The difficulties arising in the study of the immunogenicity of bacterial ribosomes and in their possible use as vaccines are due to the fact that preparative ultracentrifugation, constituting a necessary stage in most of the methods used for the isolation of ribosomes, has a low productive capacity. To develop a more effective method for obtaining Shigella ribosomal vaccines, an attempt to use the method of precipitation with 10% polyethylene glycol (PEG), proposed by Expert-Bezançon et al., has been made. The serological determination of O antigen has shown that nearly contained in the supernatant fluid S-30 can be detected in precipitated ribosomes. Taking into account the wide spectrum of the biological activity of bacterial endotoxin, it must be removed from the vaccine. The study has revealed that precipitation by means of ethanol (15-35%), low pH (4,2-4,7) and PEG (4-8%) can be used for this purpose. In accordance with the chosen method, the clarified material obtained by precipitation with 10% PEG is fractionated by means of 5% PEG which causes the complete precipitation of ribosomes, thus leaving endotoxin in the solution. Centrifugation in the density gradient of saccharose and electron microscopy have demonstrated that ribosomes isolated by this method possess typical sedimentation properties and structure. The yield of ribosomes is 3 times greater than that obtained by ultracentrifugation. Fractionation with PEG may be used as the method of the mass production of ribosomal vaccines.

Cell Fractionation↗
PubMedDate not supplied

[Autoantibody formation against the antigens of the synaptonemal complex in the syngeneic immunization of male Mus musculus].

Male mice were immunized with the suspension of synaptonemal complexes (SC) isolated from mouse spermatocytes nuclei. The indirect immunofluorescent analysis showed the active binding of sera obtained from immunized mice to SC of mouse spermatocyte spreads. At early and mid-pachytene, SC can be clearly identified in 19 autosome bivalents and in sex chromosome bivalent. According to the electron microscopic analysis, all structural elements of SC bind antibodies. Metaphase chromosomes were not stained with the immune sera. Specificity of interaction between SC components and antibodies was confirmed in a series of control experiments. Analysis of sera obtained from mice after their syngeneic immunization with isolated SC fraction suggested that certain mouse SC components induce the formation of autoantibodies. This, in turn, suggests that these SC components are meiosis-specific.

Animals↗
PubMedDate not supplied

[The dynamics of the formation of spontaneous autoantibodies to the synaptonemal complex in male mice].

Time-related changes in formation of spontaneous autoantibodies against the synaptonemal complex were studied by indirect immunofluorescence in male mice. Appearance of the spontaneous autoantibodies against the synaptonemal complex coincided with that of the cells containing synaptonemal complexes. The mouse synaptonemal complexes were binding spontaneous autoantibodies of the rabbit and human sera. The synaptonemal complexes of the equine spermatocytes were binding spontaneous autoantibodies of the mouse serum. There was no fluorescence of synaptonemal complexes on preparations of spread rye meiocytes treated with the mouse serum. Antigenic similarity was shown for the synaptonemal complex components in representatives of the different mammalian orders: rodents, odd-toed ungulates, and primates.

Aging↗
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↗