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Biomedical subjects

A L Gintsburg

Publications and source records attributed to A L Gintsburg.

At least 55 records · Page 3Linked to original sources
PubMed1991

[The creation of a test system for detecting Mycoplasma pneumoniae based on a method of directed DNA amplification].

A system for the rapid detection of M. pneumoniae, the causative agent of pneumonia in humans, has been developed. This system is based on the amplification of M. pneumoniae chromosomal DNA sequences in the polymerase chain reaction (PCR). The use of two primer sets, for nucleotide sequences of adhesion protein P1 and for nucleotide sequences of variable regions of the 16S ribosomal RNA, has permitted the detection of individual M. pneumoniae cells. The application of this technique for the study of simulated clinical material has shown that PRC is a sensitive and reliable assay and may be useful for the early detection of M. pneumoniae in infectious clinical material (blood and sputum samples).

Base Sequence↗
PubMed1991

[The genomic fingerprinting of the causative agents of sapronoses].

The genome polymorphism of the causative agents of sapronoses (Vibrio cholerae, Legionella and Leptospira) has been studied. The use of the method of genome fingerprinting [correction of dactyloscopy] has been shown to permit the differentiation of closely related strains of such causative agents. The epidemically significant strains of the causative agents of sapronoses, isolated in different geographical regions, have been found to be genotypically related, i.e., they are probably of clonal origin. Avirulent and nontoxigenic strains are genotypically heterogeneous and differ both from one another and from epidemically significant strains. Using V. cholerae as an example, the hypothesis of the appearance of potentially dangerous variants at the epidemic period in the absence of their release at the period between epidemics is considered.

DNA Fingerprinting↗
PubMed1990

[The use of a molecular DNA probe based on the cloned cytolysin gene for the identification of Legionella].

A molecular DNA probe has been obtained on the basis of recombinant plasmid pNIG carrying the Legionella cytolysin gene. The use of this probe for the identification of different Legionella species and other microorganisms has shown that it may serve as the species-specific marker of L. pneumophila. The probe has been used for the identification of new Legionella-like strains isolated from the environment.

Cloning, Molecular↗
PubMed1990

[Specific DNA probe for detecting Legionella pneumophila].

A fragment of the gene for cytolysin has been cloned. The product of the gene has been earlier identified as an immunoserological marker of Legionella pneumophila. Clones were selected by immunodetection of cytolysin gene product expression. An EcoRI 3.8 kb fragment of the genomic DNA from Legionella pneumophila strain Philadelphia-1 was used as a DNA probe that hybridized with the bacterial colonies of 20 Legionella pneumophila strains but not with the colonies of 10 other Legionella species or 8 other bacterial genera. The cloned fragment has been shown to be unique for Legionella pneumophila. The region of homology is suggested to be longer than a possible dimension of the cytolysin gene.

Cytotoxins↗
PubMed1989

[Analysis of the plasmid composition of Yersinia pseudotuberculosis strains and its use for typing pseudotuberculosis pathogens].

Electrophoresis in agarose gel has been used to study the plasmid spectra of 854 Yersinia pseudotuberculosis strains isolated from different sources. The plasmids found in the microbial strains are represented by the elements with molecular masses 82; 57; 45; 5.5; 4.4; 3.5; 2.7; 2.4; 2.3 Md. The variable spectra of plasmids is peculiar only for serovar I of Yersinia pseudotuberculosis. Plasmids p45 and p82 are classified as the main, while other plasmids as auxiliary ones. In accord with the classification all plasmid containing strains are divided into 8 plasmid strains. Using the proposed method for intraspecific typing of Yersinia pseudotuberculosis permits one to perfect the epidemiological analysis of pseudotuberculosis infection and make concrete the direction of prophylactic and antiepidemic measures.

Animals↗
PubMed1989

[Study of polymorphism of strains of Vibrio cholerae of various origins using a method of genomic fingerprinting].

Population of atoxigenic Eltor vibrios (vct-) isolated from open water has been shown to be heterogeneous by the genomic fingerprinting technique. Epidemically dangerous strains (vct+) containing the gene coding for cholera toxin have similar hybridization profile independent of time and place of their isolation. The clonal formation of vct+ strains and the absence of vct----vct+ transition of strains under natural conditions are discussed.

DNA, Bacterial↗
PubMed1988

[The role of the RS1 sequence of Vibrio cholerae in the amplification of a segment of plasmid DNA carrying the tetracycline resistance gene and cholera toxin genes].

The clones with 4 to 30-fold increased level of tetracycline resistance (TcR) were selected from the strain of Escherichia coli K-12 carrying the pCO107 plasmid. The plasmid is the cointegrate formed from the plasmids pOX38 (F-derivative) and pCT105 (pBR322-derivative carrying the vct operon of Vibrio cholerae eltor and the RSI sequence). pCO107 contains RSI at the junctions of two plasmid genomes. Using restriction analysis and Southern blot hybridization technique it was shown that increased tetracycline resistance is accompanied by amplification of the pCT105 segment of pCO107 and depends upon the presence of direct repeats of flanking RSI. Amplification of the pCT105 also resulted in increased production of the cholerae toxin (CT).

Base Sequence↗
PubMed1988

[Genomic fingerprinting of microorganisms: its use as a hybridization probe of phage M13 DNA].

Hypervariable nucleotide sequences detected by hybridization with the phage M13 DNA probe were found in the chromosomal DNAs of certain pathogenic microbial species. DNA fingerprinting, based on hybridization of M13-probe with hypervariable chromosomal DNA sequences, opens new approaches to epidemiological analysis, epidemiological prognosis, taxonomy, and other theoretical and applied fields of bacteriology.

Bacteriophages↗
PubMed1988

[A new pathogenic trait encoded by Yersinia pseudotuberculosis pVM82 plasmid].

The strains of Yersinia pseudotuberculosis isolated from patients in the course of outbreaks of infection (epidemic strains) were found to possess at least two plasmids with molecular masses of 45 and 82 MD. In contrast, the strains obtained in sporadic cases harbored different sets of plasmids, but never the 82 MD plasmids. These plasmids designated pVM82 and isolated from strains of different geographic regions of the country were identical. pVM82 have no homology with Y. pestis plasmids of the similar size coding for the FraI antigen. The pVM82 DNA was found to be composed of the 57 MD plasmid DNA and the 25 MD fragment of Y. pseudotuberculosis DNA. Using Western blot hybridization technique it was shown that the presence of pVM82 suppressed formation of antibody against some major antigenic determinants of Y. pseudotuberculosis. Immunosuppression took place when the animals were infected with bacteria grown below 20 but not at 37 degrees C. The 57 MD plasmid failed to produce immunosuppression. It was concluded that the 25 MD fragment of pFN82 encoded a novel pathogenic factor responsible for immunosuppression.

Antibodies, Bacterial↗
PubMed1987

[Plasmids and mobile genetic elements of pathogenic Yersinia bacteria].

The review of literature is devoted to molecular and genetic organization of movable genetic elements responsible for synthesis of pathogenicity factors of Yersinia bacteria. General characterization of Yersinia pathogenicity factors is given. We analysed the role of plasmids in expression of the pathogenic properties of these bacteria and the role of IS elements of Yersinia in expression of genes encoding synthesis of the pathogenicity factors. Replicative properties of Yersinia plasmids are described. The role of chromosomal genes in regulation of synthesis of the plasmid-specific pathogenicity factors is discussed.

DNA Transposable Elements↗
PubMed1987

[Construction of recombinant plasmids encoding the biosynthesis of the beta-subunit of cholera toxin].

The structure of the cholera toxin operon and the location of A and B toxin subunits have been studied by the Southern blot hybridization on filters. The gene coding for the synthesis of the cholera toxin B-subunit has been cloned in the vector plasmid pBR322. The structural gene of A-subunit has been partially deleted by the restriction endonuclease Bal31 digestion. The size of the 250 b. p. deletion has been defined by electron microscopy. The production of the cholera toxin B-subunit in Escherichia coli K12 cells has been studied.

Cholera Toxin↗
PubMed1987

[The use of the gene hybridization method for the identification of epidemiologically dangerous strains of cholera vibrios].

Using the labeled DNA fragments containing the genes for cholera toxin the strains of cholera vibrios were studied for the presence of cholera toxin genes. Vibrio cholerae strains isolated from natural water reservoirs under the favourable epidemic situation do not contain the cholera toxin genes. The DNA hybridization method was compared with other methods used in research and practical work for estimation of epidemic importance of cholera vibrios.

Animals↗
PubMed1983

[Nature of the plasmids determining the unstable inheritance of transposon Tn9 in Escherichia coli K-12].

Unstable inheritance of transposon Tn9 in the Escherichia coli strain KS7201 had been connected with its integration into a certain bacterial chromosome site (attTn9A). However, the present work shows that the transposon is situated within an unstable plasmid in this strain. A possibility of such plasmid's formation, as a result of a deletion of a part of bacteriophage lambda DNA, is shown.

Bacteriophage lambda↗
PubMed1980

Transcription termination factor rho and T-even phage development.

A functional factor rho is necessary for T-even phage development; phages T2 and T4 require different degrees of rho activity. The rho inactivation by ts-mutations in E. coli causes a reduction of some early protein synthesis and an early formation of some proteins normally typical of a later stage. Besides, it weakens the synthesis of some late proteins, impairs the capsid proteins maturation and sharply inhibits phage DNA replication in infected cells. However, in the absence of a functional rho all the proteins required for phage DNA synthesis the formed, indicating that this factor is directly involved in the process of T-even phage DNA replication. A number of rifampicin-resistant mutations supressing the rho 15 mutation and restoring the ability of cells to grow at high temperature were isolated. However these RNA polymerase mutations do not or only partially suppress the effect of rho mutations on T-even phage development and the phage DNA synthesis. The role of rho in DNA transcription and replication during bacteriophage development is discussed.

DNA Replication↗