[Inhibition of DNA amplification at individual genome sites in avirulent Mycoplasma pneumoniae strains].
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Culture Media↗
Biomedical subjects
A L Gintsburg
Publications and source records attributed to A L Gintsburg.
[The microbial world].
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Antibodies, Bacterial↗
[Use of molecular-biological methods for identifying brucella in a comparative analysis of strains, isolated from sick dogs].
Ten strains isolated from sick dogs in 1998 in St. Petersburg were studied by traditional and molecular biological methods of Brucella identification. PCR study confirmed that the isolated cultures were Brucellae, and comparative study of the traditional phenotypical characteristics and protein and antigenic composition allowed referring all the isolated strains to B. canis. Traditional identification showed similarity of 7 strains with the reference B. canis strain RM6/66, and 3 strains were similar to B. canis Mex 51 strain. These results confirmed the division of B. canis into two biovars. Polyacrylamide gel electrophoresis with sodium dodecyl sulfate demonstrated the identity of protein profiles of 10 strains isolated from dogs to the reference B. canis RM6/66 strain. Immunoblotting analysis with S- and R-specific rabbit antisera also demonstrated the identity of antigens binding IgG antibodies in the strains isolated from dogs to the reference B. canis RM6/66 strain.
Animals↗
[Participation of mobile elements in formation of properties of pathogenic bacteria].
Published reports about structural organization of genes coding for pathogenicity factors are reviewed. Many of such genes are often united into "virulence blocks" or "pathogenicity islands" and are surrounded by mobile genetic elements, promoting their transposition between related bacteria genomes and leading to changes in virulence in the course of evolution. Data on the similarity of nucleotide sequences of virulence genes in different bacteria are presented, despite differences in their localization in the relevant genomes. The role of rRNA genes in dissemination of virulence genes among different bacteria during transduction or conjugation is shown.
Bacteria↗
[Polymerase chain reaction in diagnosis and treatment control of infectious diseases].
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Animals↗
[Uncultured status of pathogenic bacteria: known and possible factors of reversible process induction].
Reviews published reports and authors' own data on the properties of unculturable bacteria, effects of environmental factors on the time course of transition in an unculturable state of different bacterial cells. Special attention is paid to reverse transfer of bacteria from unculturable to normal vegetative state. Conditions of inducing reverse transfer in in vitro laboratory conditions under different conditions of culturing and in vivo and injection of inoculates of uncultured forms of initially virulent bacteria to susceptible hosts are discussed. Probable role of some cytokinetic factors inducing transfer of bacteria from uncultured to cultured state during their transition from the environment into a host is discussed.
Bacteria↗
[Development of polymerase chain reaction-based test systems for detecting leptospira in polytypical leptospirosis foci].
Two highly sensitive test systems G and B, based on the polymerase chain reaction, were developed for indication of pathogenic Leptospira interrogans, including the serovariants appearing during outbreaks in polytypical foci of leptospirosis in the tropical zone of China. These test systems can be used for rapid diagnosis of leptospirosis in humans in foci with different etiological structure.
China↗
[The detection of mycobacteria in children and adolescents by using the polymerase chain reaction].
A polymerase chain reaction (PCR) was used for determination of mycobacterial DNA in clinical samples from children and adolescents. The results were positive in 23 and 53% of cases, respectively, while standard microbiological methods failed to show presence of any bacteria in the samples. Case histories contained information on high incidence of positive Mantoux test. Microbiologically the diagnosis was confirmed only in 7 adolescents. In children mycobacteria were not found.
Adolescent↗
[Identification of genes controlling the transition of Salmonella typhimurium bacteria to a non-culturable state].
Mutants of Salmonella typhimurium with an impaired process of transition to the nonculturable state were tainted. Mutants were divided into four phenotypic groups. In four mutants (representatives of each phenotypic group), genes with TnPhoA transposon insertions were cloned; these insertions caused a disturbance in the process of mutant cell transition to the nonculturable state. Nucleotide sequences of mutant gene fragments were determined. Comparison of nucleotide sequences obtained with a data bank on DNA nucleotide sequences of enterobacterial genomes allowed the identification of four genes involved in the control of nonculturable form generation in salmonellae.
Base Sequence↗
[Selective inhibition of DNA amplification in nonadhesive cultures of Mycoplasma pneumoniae].
Inhibition of amplification of various genome regions of Mycoplasma pneumoniae was observed in the polymerase chain reaction, and was dependent on cultivation conditions. A protein stably associated with DNA is responsible for the inhibitory effect. It is assumed that when the protein selectively associates with separate DNA regions, it can inhibit genes encoding pathogenicity factors, thus promoting mycoplasma transformation into persistent variants.
Bacterial Adhesion↗
[PCR genetic typing of pathogenic microorganisms].
Basic principles, characteristics, methodical peculiarities, and strategy of choice of PCR-mediated methods of genetic typing are discussed. Existing and potential fields of application of these methods for tackling many unsolved problems of molecular epidemiology of bacterial infections are considered. Advantages of PCR-mediated methods of genetic typing compared with other techniques used for studying genomic polymorphism are demonstrated. Possibilities for developing novel PCR-mediated methods with the aim of improving genetic typing are analyzed.
Bacteria↗
Development of a diagnostic test for Yersinia pestis by the polymerase chain reaction.
A 501 bp caf1 gene fragment and a 443 bp of pla gene fragment carried by 100 kb (pFra) and 10 kb (pPst) species-specific extrachromosomal replicons, respectively, were used as targets to study the conditions under which DNA amplification by polymerase chain reaction (PCR) may be applied to detect and identify Yersinia pestis DNA in cell lysates of pure cultures and biological samples. The sensitivity limit of PCR with the crude cell lysates of Y. pestis EV was estimated as 10-50 cfu in reaction mixture. When target Y. pestis EV cells were mixed with fresh blood of white mice, which contained 0.4% potassium citrate, the PCR detection level varied from 400 to 100 cfu ml-1 of blood depending on the method used for preparing the sample. In our tests PCR was effective for the detection of yersinia in the blood of white laboratory mice experimentally infected with virulent Y. pestis KM638 strain. This method can be considered convenient for routine detection and identification of Y. pestis.
Animals↗
[Test-systems of polymerase chain reaction for determining the tuberculosis pathogen].
Two polymerase chain reaction-based test systems were used to identify Mycobacteria tuberculosis by using a clinical material for practical health purposes. The former test system strictly specifically enables M. tuberculosis to be detected. The latter also allows one to differentiate a BCG vaccine strain from the M. tuberculosis. The test systems were tested by using 11 clinical sputum samples, three of them were taken from patients with fibrocavernous tuberculosis, two from those with focal tuberculosis and one from that with infiltrative one, 5 from those with non-specific pulmonary diseases (chronic bronchitis and asthma). In addition, one serum sample from a patient with fibrocavernous tuberculosis was examined. All tests obtained from patients with tuberculosis were positive, whereas those from patients with non-specific pulmonary diseases were negative. This suggests that differentiation of BCG vaccine strain from M. tuberculosis can be used both in model experiments and in the study of clinical material lysates.
BCG Vaccine↗
[Improvement of a method for detecting of strains of the plague microbe using polymerase chain reaction].
Three pairs of oligonucleotide primers, complementary to nucleotide sequences of Yersinia pestis plasmids (pPst, 9.5 kb; pCad, 70 kb; pFra, 95 kb), were used in polymerase chain reaction for high-sensitive specific detection of plague pathogen. Primer pairs P1,P2,C1,C2, and F1,F2 were used to amplify fragments of pla gene (plasmid pPst), yop1 gene (plasmid pCad of plague microbe), and caf1 gene (plasmid pFra), respectively. The method developed enables specific detection of strains from all natural loci in Russia and contiguous states as well as strains of oceanic origin. Sensitivity of method is 50-100 CFU/ml. Primer sequences enable to amplify gene fragments, located in three own plasmides of plague microbe, in the same reaction mixture. The method offers identification of plague microbe and determination of its virulence and epidemic significance.
Base Sequence↗
[Design of a chromosomal DNA probe species specific for Yersinia pestis].
A 14.8 kb DNA fragment from the chromosome of Yersinia pestis TWJ was cloned and the restriction map constructed. The fragment designated as T16 and its subfragments were tested in dot-hybridization with strains of Yersinia genus and other members of Enterobacteriaceae. A species-specific DNA probe (designated MK) was constructed on the basis of the T16 fragment. As judged from restriction analysis, blot-hybridization experiments and, partially, sequencing, significant homology exists between the MK DNA probe and this one developed by Bardarov et. al. (1990). A repeated sequence in two copies was discovered in the MK fragment.
Base Sequence↗
[Study of the epidemic significance of noncultivated forms of Vibrio cholerae by the polymerase chain reaction].
A specific method of the isolation of the cholera toxin gene by the directional amplification of DNA in the polymerase chain reaction (PCR) has been developed. The product of this reaction has a molecular weight of 440 sequence pairs and is a DNA fragment located on the A-subunit of V. cholerae gene vct. The sensitivity of the method permits the detection of one bacterial cell in the reaction mixture. The method is effective when V. cholerae purified DNA, cell lysates and the DNA of total microflora isolated from the water of natural springs are used. The study of water samples from natural water bodies by the method of PRC has revealed cholera toxin genes of V. cholerae noncultivated forms ni 5 out of 7 water samples taken from natural water bodies at the regions of Azerbaijan endemic for cholera and made it possible to evaluate the number of V. cholerae. The prospects of using PCR for the control of the epidemiological situation in regions endemic for cholera are discussed.
Azerbaijan↗
[Genomic polymorphism of bacterial infection pathogens].
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Bacteria↗
[Alternative localization of the determinant of pathogenicity coded by the Yersinia pseudotuberculosis pVM82 plasmid].
The chromosomal DNA regions in Yersinia pseudotuberculosis strains occur that are homologous to 25 Md DNA segment of the plasmid pVM82 encoding the bacterial capability of immunosuppression. The character of the chromosomal DNA regions dispersion reacting with the 25 Md segment probes is different in epidemiologically hazardous and nonvirulent strains of Yersinia pseudotuberculosis. The specific DNA regions occur as well as identical ones. The suppression of antibody formation to a number of main Yersinia pseudotuberculosis antigens by epidemiologically hazardous strain is demonstrated. The suppression is analogous to the one previously described for Yersinia pseudotuberculosis strains harbouring the plasmid pVM82.
Blotting, Southern↗