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V G Debabov

Publications and source records attributed to V G Debabov.

At least 19 recordsLinked to original sources
PubMed1991

[Site-directed mutagenesis with the use of addressed fragmentation of single-stranded DNA for obtaining hybrids of homologous proteins].

Site-directed multiple mutagenesis to obtain hybrids of homologous proteins was carried out by means of the oligonucleotide-targeting digestion of ss DNA. The procedure is more convenient, rapid and simple than the step-by-step approach. To demonstrate different approaches to targeting digestion of ss DNA, NcoI, HinfI, FokI endonucleases were used for DNA cleavage. A hydride of the human and porcine IFN-alpha-2-genes has been constructed.

Animals↗
PubMed1991

[Use of uracil-repair selection for extensive DNA sequence deletions].

A procedure for extensive deletion mutagenesis of DNA using the uracil repair system is exemplified by reconstruction of the pBR322 replication regulatory region cloned into M13tg131. By means of an oligonucleotide primer the 116-nucleotide fragment was excised and four nucleotides were introduced to form a BglII restriction site. Use of the uracil repair selection provided a 30-fold increase in the deletion mutagenesis efficiency.

Base Sequence↗
PubMed1977

A suitable method for construction and cloning hybrid plasmids containing EcoRI-fragments of E. coli genome.

A convenient procedure for the isolation of specific EcoRI-fragments of E. coli genome and their amplification on Km-resistance plasmid victor CK delta11 is described. The hybrid molecules were constructued in vitro using EcoRI-digestion, followed by ligation. Then appropriated E. coli strain was transformed with ligated DNA mixture and hybrid plasmids CK delta11-arg+, CK delta11-his+, CK delta11-thr+ and CK delta11-leu+ containing loci of E. coli genome were selected by molecular cloning. The hybrid plasmids obtained consisted of one EcoRI-fragment of initial plasmid CK delta11 and one respective specific portion of E. coli genome.

Arginine↗
PubMed1977

[Isolation and preliminary characteristics of the extrachromosomal elements of Bacillus thuringiensis DNA].

Centrifugation of Bacillus thuringiensis 351 DNA in CsCl-ethidium bromide density gradient has revealed, besides the main band of chromosomal DNA (p = 1.56 g/cm2), some additional bands with higher density, which usually correspond cicle superhelix DNAs, are revealed. 6 discrete bands are observed under electrophoresis of total fraction of minor DNA bands, which suggests, that the preparation contains cicle DNAs of different size. The treatment with DNAse results in the appearance of 3 bands corresponding to opened cicle DNA forms, their molecular weight being 12-10(6)--4-10(6) daltons. Cicle super-helix and opened cicle DNA forms are found in minor fraction by means of electrone microscopy. Statistical analysis has revealed the presence of at least three types of cicle molecules of different size. The variant 351-10, free of extrachromosomal elements, is isolated after ethidium bromide treatment at high temperature. Possible mechanisms of cicle DNAs formation are discussed. Biological function of DNA extrachromosomes fragments in Bacillus thuringiensis is still obscure.

Bacillus thuringiensis↗
PubMed1977

[Effect of EcoRI restrictase on the transforming DNA of different bacilli].

The transforming activity of DNA from Bacillus subtilis 168, Bac. subtilis W23, Bac. subtilis NRS and Bac. aterrimus after the EcoRI restrictase treatment was studied. The auxotrophic strains of Bac. subtilis 168 were used as recipients in bacterial transformation. The transforming activity for different markers decreased up to 0.001--6 per cent from the initial level for different Bacilli DNAs. In some cases the sensitivity of the same marker from different Bacilli differed in more than 50 times. Bac. subtilis and Bac. aterrimus have demonstrated the maximal differences. Such differences can be used for the identification of close related Bacilli.

Bacillus subtilis↗
PubMed1976

[Transforming activity of Escherichia coli DNA fragments obtained following endonucleolytic splitting by EcoRI restrictase].

Escherichia coli DNA with molecular weight of 20 - 10(6) daltons was digested by restriction endonuclease EcoR1, and the transforming activity of resctricts was studied. The transforming activity of restricts for two markers (Leu and Arg) was 2-5 fold increased, for two other markers (Thr and His) was not changed, and for one marker (Pro) was completely absent. The molecular weight of E. coli DNA restricts was 7,5-10(6) daltons. An increase and a decrease of the transforming activity for different markers appeared to be the result of two effects: 1) more efficient uptake of low molecular weight DNA into the cell and 2) the inactivation of markers as a result of location close to EcoR1 induced break.

Catalysis↗
PubMed1976

[Simple method for isolation of three DNA-polymerases from E. coli using chromatography on DNA-cellulose].

A simple method for isolation of three DNA-polymerases from E. coli is developed; it is based on properties of the enzymes to bind with single-stranded DNA, fixed on cellulose. DNA-polymerases I, II and III were identified by their relation to templates, ionic strength, heat denaturation and inhibition of the activity with agents which blocked sulfhydryl groups. After purification which included chromatography on DNA-cellulose as well as fractionation with phosphocellulose and gel-filtration through Sephadex G-100, the enzymes were free the endonucleases contamination.

DNA Polymerase I↗
PubMedDate not supplied

[Use of the polymerase chain reaction for typing allelic variants of the human HLA-DQA1 by hybridization with oligonucleotide probes, specific for specific alleles].

Class II HLA molecules are the most useful markers for susceptibility to different autoimmune diseases, including insulin-dependent diabetes mellitus (IDDM) and rheumatoid arthritis (RA). Polymerase chain reaction and hybridization with a set of allele-specific oligonucleotide have been used for analysis of allelic sequence variation. The analysis of frequencies of HLA-DQA1 alleles among 10 patients of the russian population revealed a uneven distribution. We have developed a method for preparing non-radioactive oligonucleotide probes with terminal deoxynucleotidyl transferase and Bio-11-dUTP. Comparison of biotinylated and 32P-labeled hybridization probes gave the same sensitivity for HLA-DQA1 typing of amplified DNA. Amplification of the HLA-DQA1 gene has been successful on 10 pg of total DNA. This amount of DNA is close to the amount of DNA in a single cell. Alternatively, HLA-DQA1 typing could be based on the analysis of buccal cells of saliva that would avoid the problem of individuals who object to giving blood samples.

Alleles↗
PubMedDate not supplied

[Elimination of introns from the interleukin 1 beta genome by DNA amplification and expression of interleukin 1 beta in Escherichia coli].

The use of the polymerase chain reaction was proposed for intron excision from genomic genes with known nucleotide sequences. Three exons (5, 6 and 7) of genomic interleukin 1 beta gene were amplified by means of thermostable DNA polymerase TthI from Thermus thermophilus on the base of cloned in M13 phage human genomic interleukin 1 beta gene. Synthetic oligonucleotides complementary to sequences flanking exons were used as primers. The fragments obtained by exon DNA amplification were joined in the correct order due to reciprocal complementation of end sequences, that was foreseen during synthesis of oligonucleotide primers followed by amplification of the enlarged fragments. As a result the structural interleukin-1 beta gene consisting of three exons was assembled. DNA sequences carrying the ATG initiation codon and XbaI recognition site at the 5'-end, and PstI recognition site at the 3'-end (essential for insertion into the expression vector) were formed by the additional end sequences of primers. The nucleotide sequence analysis of the obtained structural gene revealed its complete identity with natural interleukin 1 beta human gene. We created the expression vector pPR114 with phage lambda promoter PR thermo-inducible in case of the cIts857 repressor presence in cells. It was used for expression of the present gene. The interleukin 1 beta synthesized in E. coli had biological activity.

Bacteriophages↗
PubMedDate not supplied

[Influence of protein bound with single-stranded DNA on the synthesis of RNA and poly(A). III. Protein product of F1 gene 5].

Influence of the protein product of F1 phage gene 5 (protein 5) on the synthesis RNA and poly(A) in vitro was studied. It has been shown, that protein 5 has no effect on the transcription of the native DNA by E. coli RNA-polymerase, but completely prevents RNA and poly(A) synthesis on the denatured or single-stranded DNA at the protein/DNA ratio 10:1. Protein 5 inhibits poly(A) synthesis with oligo(dT)9 and oligo(dT)12 as a template, preventing binding of enzyme to the oligonucleotide. After the initiation of the poly(A) synthesis the inhibition becomes considerably wearer. The biological function of the inhibition of the transcription by "unwinding" proteins is discussed.

Coliphages↗
PubMedDate not supplied

[Using a combined transcription-translation system for determining the role of cryptic plasmids of Bacillus thuringiensis].

The possibility of entomocyde crystal protein synthesis was studied using a heterological cell-free system with Bacillus thuringiensis plasmid DNA as template. The high level of template activity is usual for Bac. thuringiensis plasmid DNA. Immunochemical studies of the in vitro synthesized polypeptides showed that Bac. thuringiensis plasmid DNA does not direct crystal protein synthesis.

Bacillus thuringiensis↗