Biomedical subjects

A L Gintsburg

Publications and source records attributed to A L Gintsburg.

At least 91 records · Page 5Linked to original sources

PubMedDate not supplied

[Molecular genetic typing of methicillin-resistant Staphylococcus aureus strains, isolated in hospitals of different regions of the Russia and Belarus].

The study of the length of the amplification products of the coagulase gene with the subsequent restriction analysis (the method of PCR--restrictive fragment length polymorphism, or RFLP) was used for typing 90 S. aureus strains. Among the strains under study, 78 were methicillin-resistant S. aureus (MRSA) strains, including 74 obtained in 1986 - 2002 in hospitals of different cities of the Russia and Belarus, as well as epidemic strains EMRSA-1, -2, -3, -12, obtained from the National Laboratory of Health, London (UK). The use of this method made it possible to type all the strains under study, which were differentiated into 9 groups by means of endonuclease Sfo1 and 7 groups by means of Alu1. Majority of clinical MRSA strains, belonged, according to the type of restriction, to groups 4 and 5. The study of the coagulase gene by the method of PCR - RFLP made it possible: to analyze the epidemic situation in hospitals for a period of several years; to compare the properties of strains isolated in different hospitals; to establish the genetic relationship of strains, isolated in 1998 - 2002, with strains, isolated in 1986 - 1990. The results of the study suggest that at least two epidemic MRSA strains, genetically similar to international strains, circulate in hospitals of Russia.

Bacterial Proteins↗

PubMedDate not supplied

[Virulent properties of hospital strains of bacteria of the Burkholderia cepacia complex, isolated in hospitals of Moscow].

The results of the study of hospital strains of the B. cepacia complex, isolated in hospitals of Moscow, with the use of phenotypical and molecular-genetic methods are presented. The phenotypical methods made it possible to differentiate Russian strains and classify them with a group of genomovars (I, III, IV). As the result the epidemic importance of the strains with epidemic markers, having specific characteristics for every clinic, was determined. The detection of the collection of genes cepI and cepR in the strains made confirmed the epidemic importance of the stains which had, due to the regulatory "quorum sensing" (QS) system, the potential capacity for inducing infection and persisting in the patient's body. The presence of gene cepR in all strains and the absence of gene cepl in 33% of strains gave evidence to suggest that in some strains the activation of the production of pathogenicity factors required the presence of other bacteria having the fully developed QS system. Thus, the new complex approach with the use of phenotypical and molecular-genetic methods permits more precise identification of the source of hospital infection induced by the bacteria of the B. cepacia complex.

Bacterial Proteins↗

PubMedDate not supplied

[Detection of the genes of pyrogenic toxins of superantigens in clinical isolates of methicillin resistant Staphylococcus aureus].

The content of methicillin resistant S. aureus (MRSA) genes, coding the synthesis of staphylococcal enterotoxins A, B, C (sea, seb, sec) and the toxin of the toxic shock syndrome (tst-H) which was classified with pyrogenic toxins of superantigens (PTSAgs), was studied with the use of PCR amplification. The study revealed the specific features of the content of genes sea and sec, detected in epidemic strains, identified earlier and found to circulate in Russian hospitals. Among the isolates, genetically related to international epidemic strain EMRSA-1, isolates containing no gene sea were detected, while among the isolates genetically related to strain EMRSA-2, isolates containing not only gene sea, but also gene sec were detected, which was indicative of the tendence of this epidemic strain in the direction of further acquisition of pathogenicity genes. As revealed in further studies, among the cultures obtained in bacteriemia, 88% contained gene sea. Two out of three isolates obtained from patients with the symptoms of toxic shock also contained this gene. The differences in the content of genes PTSAgs (sea, seb, sec and tst-H) could serve as a genetic criterium for the differention of isolates circulating in a hospital, as well as for a more complete characterization of the epidemic strains MRSA. The determination of the given genetic markers in genetic strains in circulating strains will make it possible to prognosticate the structure, severity and outcomes of hospital infections. The conditions of PCR amplification for the determination of genes sea, seb, sec and tst-H, as well as multiplex PCR for the determination of genes sea and seb, were developed.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Role of lactic acid bacteria in the spread of antibiotic resistant bacteria among healthy persons].

The wide use of antibiotics in livestock raising has contributed to the selection and accumulation of representatives of commensal microflora, as well as pathogenic bacteria, colonizing livestock and poultry. For this reason the problem of the possible transfer of antibiotic-resistance genes along the chain from bacteria, autochthonous for agricultural animals, to bacteria used for the production of foodstuffs, which are incorporated into normal microflora and may thus participate in the exchange of these genes with bacteria, enteropathogenic for humans, is a highly important task of medical microbiology. The article deals with the review of experimental data, indicative the possibility of the appearance of antibiotic-resistant pathogenic bacteria due to the transfer of antibiotic-resistance genes via alimentary chains.

Animal Husbandry↗

PubMedDate not supplied

[The role of "quorum sensing" regulation system in symbiotic interaction of bacteria Burkholderia cepacia and Pseudomonas aeruginosa during mixed infection].

Data concerning mechanisms of strengthening virulence of bacteria B.cepacia and P.aeruginosa during experimental mixed-infection are submitted. Results of in vitro studies of acylhomoserine lactones (AHL) with various length of a carbon lateral circuit have shown that butanoyl-homoser-ine lactone (C4), hexanoyl-homoserine lactone (C6) and octanoyl-homoserine lactone (C8) separately and in various combinations display different effects on growth of bacteria, formation of colonies and production of pathogenicity factors. Experiments on animals have shown strengthening virulence of bacteria B.cepacia by C4, C6 and C8 lactones when introduced simultaneously. Strengthening of virulence of the P.aeruginosa strain under the action of lactone C6 and simultaneous action of C4, C6 and C8 lactones was observed. The data obtained give grounds for assumption, that bacteria may use exogenous lactones, including those produced by closely related bacteria, during their life cycle.

4-Butyrolactone↗

PubMedDate not supplied

[Biofilm formation by different strains of Salmonella typhimurium in artificial systems].

The ability of 14 different strains of Salmonella typhimurium to biofilm formation depending on genotype and culture conditions was investigated in artificial systems: in 96-well plastic microtitre plates, plastic and glass tubes, plastic Petri dishes and on microscope glasses. Quantitative biofilm growth was monitored by using an assay based on crystal violet staining, while planctonic growth in the same cultures was monitored by absorbance in iEMS Reader MF, and qualitatively--by digital photo and visually. Optimal rate between growth and biofilm indications for all strains was determined at initial cell concentration 10(6-7) KOE/ml and culture incubation at t degrees 28 degrees C. The nutrient content of the medium significantly influenced the quantity of produced biofilm. The nutrient broth LB without NaCl was more effective in promoting biofilm formation, than LB itself. The least quantity of biofilm was formed in water. The genotype of the strains also critically influenced the quantity of produced biofilm. Nonmotile mutants cells had reduced ability to form biofilm. RpoS mutant cells produced significantly less biofilm as compared with cells of isogenic parent strains. The chemical content of plastic and glass also influenced biofilm formation.

Bacterial Proteins↗

PubMedDate not supplied

[Apoptosis of host cells regulation by Chlamydia].

In a study on the impact of chlamydial infection on host cell apoptosis, C. trachomatis were shown to protect host cell against staurosporin-induced apoptosis only at the middle stage of infection development (at 20 hours post infection), C. pneumoniae--at different stages of its growth cycle (from 2 to 7 day post infection). We found, that C. trachomatis elementary bodies fail to inhibit staurosporin-induced apoptotic stimuli. The clear antiapoptotic effect of cell lysate filtrate, infected with C. trachomatis, was demonstrated by cytometric analysis and luminescent microscopy. Our findings make it possible to use biochemical approach to identification of chlamydial antiapoptotic factors in future. Investigations directed at chlamydial antiapoptotic activities may aim to create the therapies of chronic chlamydial infection.

Animals↗

PubMedDate not supplied

[Immunization with cellulose-immobilized antigens. The development of A. E. Gurvitch concept].

A highly purified TUL4-CBD chimeric protein was obtained by one stage purification method. TUL4-CBD protein consists of TUL4 Francisella tularensis mature peptide sequence, Gly-Ser spacer and cellulose binding domain (CBD) of Anaerocellum thermophilum. The TUL4-CBD protein was shown to induce production of specific antibodies to TUL4 protein in laboratory animals.

Adjuvants, Immunologic↗

PubMedDate not supplied

[The induction of protective immune response in mice vaccinated by recombinant avian adenovirus CELO expressing glycoprotein G of the rabies virus].

The recombinant avian adenovirus CELO-gpRb expressing glycoprotein G of rabies virus (strain TS-80, ARRIW&M, Pokrov, Russia) was used for mice vaccination against rabies. Double intramuscular immunization by recombinant CELO-gpRb adenovirus in a dose 10(9) pfu per mouse caused the induction of virus neutralizing antibodies (VNA) synthesis in 78% of mice, while twice repeated intradermal injections of the recombinant adenovirus failed to induce the VNA production. The protection level in groups of vaccinated mice after intracerebral injection of CVS rabies virus in a dose of 100 MLD50 was equal to 45% at single intramuscular immunization and to 91% after twice repeated intramuscular immunization. The recombinant adenoviral vaccine against rabies, based on CELO viral genome, has a good perspective for domestic and wild animal vaccination, not only due to rather high protection level, but also because the production of adenoviral CELO vaccine in chicken embryos is of high technology and inexpensive.

Animals↗

PubMedDate not supplied

[Formation of biofilms as an example of the social behavior of bacteria].

This paper is a brief review of data on bacterial biofilms that occur inside and outside of host organisms. Such biofilms are of great ecological and clinical importance. The role of interspecies communications in the development of bacterial biofilms and infectious diseases is particularly emphasized. Considerable attention is given to the electron microscopic study of biofilms formed by Salmonella typhimurium cells incubated as a broth culture in microtubes without aeration. Bacterial samples taken from the biofilm and planktonic culture grown in the same microtube were comparatively investigated by transmission electron microscopy.

Bacteria↗

PubMedDate not supplied

[Interaction of DNA with RNA-polymerase from Escherichia coli cells infected and uninfected with T2 phage].

RNA polymerase from T2 infected E. coli has greatly reduced activity as compared to the enzyme from uninfected bacteria. Nevertheless both RNA polymerases synthesize heterogenous RNA species with the same maximum corresponding to chain length of 5600 nucleotides on T2 DNA. Rifampicin-challenge experiments suggest that these enzymes have identical kinetics of RNA chain initiation and elongation but their ability to form rapidly starting (RS) and delay starting (I) binary complexes with phage DNA are different. The temperature of I leads to RS transition on T2 DNA is 15 degrees for E. coli holoenzyme, but is 35 degrees for the RNA polymerase from infected cells. The transition temperature depends both on the core and on sigma fraction. Shift temperature technique was developed to investigate the kinetics of I in equilibrium RS complexes rearrangements and their temperature dependence. The rate of these rearrangements is strongly temperature dependent for E. coli holoenzyme, while for RNA polymerase from infected cells it is much lower and is practically temperature independent. From the kinetic data and from the temperature dependence of equilibrium RS-complexes concentration, the rate constants of RS-complexes formation and decay are calculated. The kinetic data obtained in rifampicin challenge experiments are in agreement with the data on the dissociation of DNA-enzyme complexes performed by the filter assay.

Chemical Phenomena↗

PubMedDate not supplied

[Effect of Escherichia coli mutations affecting the transcription termination rho on the development of T-even phages].

The functionally active transcription termination factor rho is necessary for the T-even phages development. The inactivation of the factor by thermosensitive E. coli gene rho mutations results in blocking phage development. It should be noted that phages T2 and T4 require different levels of this factor's activity. The synthesis of some early proteins diminishes during factor rho inactivation and a number of proteins typical for a later stage are observed early in infection. Under the conditions of the factor rho being inactivated the synthesis of a number of proteins is weakened late in infection and the capside proteins maturation is impaired. Alongside with this the factor rho inactivation results in a sharp decrease of phage DNA replication in infected cells. The obtained data suggests that in the absense of functionally active factor rho all the proteins necessary for phage DNA replication are formed. Besides, this factor is directly involved in the process of T-even phages DNA replication. One may conclude that the inability of T-even phages to develop in mutant cells rho is to a greater extent due to the impairment in phage DNA replication than to its transcription. The possible role of the factor rho in the process of DNA replication is discussed.

DNA Replication↗

PubMedDate not supplied

[Identification of tuberculosis pathogens in clinical material using the polymerase chain reaction].

The authors examined the possibility of detecting M. tuberculosis cells in various types of diagnostic material (sputum, blood, bone marrow, bronchoalveolar lavage fluid) from tuberculosis patients using polymerase chain reaction (PCR). The developed PCR-based test systems helped detect M. tuberculosis in 48 (90.6%) out of 53 tuberculosis patients, in contrast to much slower microbiological methods which permitted detection of Mycobacteria in only 21 (39.6%) patients. High specificity and virtually no false-positive results of PCR were demonstrated in testing diagnostic material from patients with chronic nonspecific pulmonary diseases and from children with lympholeukemia and anemia.

Bacteremia↗

PubMedDate not supplied

[The detection and study of the dynamics of the count of nonculturable forms of Yersinia pseudotuberculosis in the environment by using the polymerase chain reaction].

On the basis of the polymerase chain reaction (PCR) a test system permitting the detection of Y.pseudotuberculosis in different environmental objects was developed. On a model approximating natural conditions the dynamics of the amount of these bacteria in sterile soil extract were studied. The comparison of the amount of Y.pseudotuberculosis, determined in terms of colony forming units and by the detection of their DNA marker fragment with the use of PCR, showed the possibility of the transition of Y.pseudotuberculosis cells into the noncultivated state during their persistence in the aqueous soil extract.

Bacteriological Techniques↗

PubMedDate not supplied

[Cloning and expression of the phosphatidylinositol-specific phospholipase C gene from Listeria monocytogenes].

The gene for phosphatidylinositol-specific phospholipase C (PI-PLC) of Listeria monocytogenes has been cloned and shown to be expressed in Escherichia coli cells from own as well as from the lactose gene promoter. The recombinant plasmid has been constructed on the basis of pRIT2T vector and carries the hybrid gone. 3-end of which is a fragment of protein A gene of Staphylococcus aureus. 3-end is a gene for phospholipase plcA, both in the same reading frame. The resultant construction is shown to code in Escherichia coli cells for the hybrid recombinant protein A:Pl-PLC. Purified preparation of the hybrid protein and polyclonal rabbit antiserum to it were obtained. The obtained antiserum to the hybrid protein containing phospholipase as en C-end domain has been shown to react specifically to phospholipase in Escherichia coli recombinant strain harbouring the constructed recombinant plasmid as well as the one in the culture fluid of listeria.

Base Sequence↗

PubMedDate not supplied

[The effect of changes in the cultivation conditions on the amplification of different Mycoplasma pneumoniae genes].

In experiments carried out with the use of the polymerase chain reaction the inhibition of the amplification of several regions of M. pneumoniae genome, depending on the conditions of their cultivation, has been observed. We suggest that protein, selectively binding with individual sites of DNA, is capable of inhibiting the expression of genes coding pathogenicity factors and thus contributes to the transformation of mycoplasmas into persistent forms.

Chromosomes, Bacterial↗

PubMedDate not supplied

[The use of an amplification test system for detecting persistent mycoplasmas].

A DNA amplification test system for the detection of Mycoplasma fermentans in clinical specimens was developed. The system was used for the analysis of biological specimens obtained from experimentally infected animals. The infective agent could be detected during the whole period of observation (6 months). High sensitivity of the polymerase chain reaction made it possible to detect M.fermentans in much greater number of cases than with the use of serological techniques.

Animals↗

PubMedDate not supplied

[Is sarcoidosis a chronic persistent infection?].

The study carried out with the use of microbiological diagnostic methods has revealed that in 67% of cases specimens obtained from sarcoidosis patients for analysis contain different forms of mycobacteria (typical Mycobacterium tuberculosis and granular forms of mycobacteria). The content of typical and granular forms of mycobacteria detected in diagnostic specimens has been shown to differ, depending on the clinical form of sarcoidosis: as a rule, in cases of the sluggish course of sarcoidosis granular forms of mycobacteria are detected, while during the exacerbation of the disease and in cases of the acute course of newly diagnosed sarcoidosis the proportion of typical M.tuberculosis increases. To verify M.tuberculosis with greater certainty, two highly sensitive and specific amplification test systems have been developed on the basis of polymerase chain reaction. In this article the goals of microbiological and molecular genetic investigations which may jointly give direct proofs of the etiological importance of mycobacteria in sarcoidosis are considered and discussed; sarcoidosis may probably be regarded as chronic persistence infection.

Animals↗