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Biomedical subjects

G P Somov

Publications and source records attributed to G P Somov.

At least 19 recordsLinked to original sources
PubMed2006

Effect of temperature on synthesis of polyphosphates in Yersinia pseudotuberculosis and Listeria monocytogenes under starvation conditions.

It was found that at low temperature (6-8 degrees C) in the absence of nitrogen supply and at the presence of phosphate ions in the medium, Yersinia pseudotuberculosis and Listeria monocytogenes are able to actively synthesize reserve substances as polyphosphates. Most of the bacterial polyphosphates are alkali-soluble, especially at the preliminary stage of cell growth (lag-phase). This is proved by electron microscopic studies of ultrastructure of model microorganisms. During a long starvation period under conditions of carbon and energy source deficit, L. monocytogenes and Y. pseudotuberculosis consume this biopolymer for biosynthetic and bioenergetic processes.

Culture Media↗
PubMed2005

[Experimental study on impact of salmon milt DNA on T-cellular immunity].

The impact of a biologically active food supplement containing salmon milt DNA on cellular immunity was experimentally studied. It was shown that the DNA had a dose-dependent stimulating effect on lymphocyte transformation, stimulated the DTH response and protected from experimental listeriosis infection.

Animals↗
PubMed2003

Adaptation variability of Yersinia pseudotuberculosis during long-term persistence in soil.

Adaptation changes in the morphological and biological characteristics of pathogenic Yersinia pseudotuberculosis inhabiting a model soil ecosystem for a long time were studied. Changes in cultural, biochemical, and morphological characteristics of Yersinia and a decrease or loss of virulence were observed under these conditions. The detected changes were phenotypical, i. e. several passages in common nutrient media restored the original characteristics of the strain.

Adaptation, Biological↗
PubMed2000

Ultrastructure of Yersinia pseudotuberculosis inhabiting the soil for a long time.

Ultrastructural changes in the population of pathogenic Yersinia pseudotuberculosis inhabiting a model soil ecosystem for a long time were studied. Changes in the bacteria were mainly adaptive until the 8th month of the experiment, their capacity to binary division was preserved. After 9 months cell structure changed: extracellular amorphous matrix appeared, probably due to increased mucus production.

Soil Microbiology↗
PubMed1999

Autotrophic assimilation of CO2 and C1-compounds by pathogenic bacteria.

We demonstrate for the first time that the pathogenic bacteria Yersinia pseudotuberculosis and Listeria monocytogenes (pathogens of saprozoonoses) are capable of chemolithoautotrophic assimilation of CO2. Low temperature is favorable for better absorption of CO2 by these bacteria; this is supported by increased enzymatic activity of carbonic anhydrase acting as the supplier of the substrate to the site of carboxylation. Data of radioisotopic methods indicate that assimilated labeled carbon of CO2 is incorporated into all major cell biopolymers. The bacteria can utilize not only CO2, but also other C1-compounds for biosynthesis.

Carbon↗
PubMed1995

[A secreted trypsin-like proteinase from Yersinia pseudotuberculosis].

A proteolytic enzyme splitting casein and catalyzing the hydrolysis of the ester bond in the synthetic substrate, BAEE, in a trypsin-like manner, has been isolated from the cultural filtrate of Yersinia pseudotuberculosis using ultrafiltration and gel-filtration. The molecular mass of the enzyme is 110 kDa. The rate of hydrolysis is proportional to the enzyme and substrate concentrations which is typical for the kinetics of enzymatic reactions. The Km value for the Y. pseudotuberculosis enzyme is 2.5.10(-3) M. The optimal conditions for the enzymatic reaction are as follows: pH 7.4-8.0 (phosphate buffer) and 37 degrees C. The enzyme is inhibited by phenylmethylsulfonylfluoride and tosyllysinechlormethylketone, the specific inhibitors of serine proteinases and trypsin, respectively. These and literary data on bacterial proteinases are suggestive of their possible role as major factors in bacterial pathogenicity.

Caseins↗
PubMed1990

[The basic features of the pathogenesis of pseudotuberculosis (yersiniosis)].

A new pathogenetic pattern of pseudotuberculosis has been derived on the basis of original clinical, anatomical and experimental findings as well as literature data. Careful consideration is given to: a basic mode of infection (alimentary), emergence of the primary affection with a rapid blood invasion by the agent (primary bacteremia), development of specific sensitization, multiorgan secondary focal impairment with lymphogenic dissemination of the infective agent (specific pseudotuberculous polyadenitis), formation of secondary immunodeficiency, consequent repeat bacteremias, recurrences, symptoms of infectious process aggravations, immunological rearrangement with dominating delayed hypersensitivity. As a rule, the disease terminated by elimination of the secondary foci and recovery.

Humans↗
PubMed1989

[Tick-borne encephalitis in the Maritime Territory].

On the basis of epidemiological analysis carried out at the period of 1940-1987, a decrease in tick-borne encephalitis (TBE) morbidity was registered; at the same time time the disease invariably took, as before, a clinically severe course. The most dangerous foci of TBE were found to be located in the southern Okhotsk region grown with dark coniferous forests. The subsiding and activation of the natural foci of TBE in different regions of the territory were established and some heretofore unknown foci in southern regions of the Maritime Territory were found. Ixodes mites inhabiting the Maritime Territory were shown to have a low level of virus carriership, thus causing the low level of population immunity to TBE virus. Combined foci of TBE and Powassan encephalitis were found.

Age Factors↗
PubMed1986

[Pathogenetic significance of the psychrophilia of Yersinia pseudotuberculosis].

The work presents the data indicating that the temperature of Y. pseudotuberculosis cultivation is very important in regulating the activity of pathogenicity factors, necessary for the initiation of the pathogenic process in the cells of the macroorganism. Low temperature (8-10 degrees C), necessary for the growth of Y. pseudotuberculosis, facilitates the activation of invasive and toxic pathogenicity factors. At a growth temperature of 37 degrees C the inhibition of such necessary attributes of virulence as adhesion and invasion into epithelial cells occurs in Y. pseudotuberculosis, which decreases the capacity of these bacteria for inducing the infectious process. The virulence of Y. pseudotuberculosis population, lost as the result of its cultivation in synthetic culture media at a temperature of 37 degrees C, has been found to be restored at low temperature.

Animals↗
PubMed1984

[Fermentative mechanisms of the psychrophilicity of Yersinia tuberculosis].

The specific activity of urease, nitrogenase, hialuronidase and neuraminidase in Y. pseudotuberculosis grown in different culture media and at different temperature has been studied. These enzymes have been found capable of functioning at both relatively low (2-8 degrees C) and high (37 degrees C) temperatures. The thermoadaptive properties of Y. pseudotuberculosis within a wide range of temperatures are ensured by the constant presence of isoenzymes, functioning only at low temperatures or only at high temperatures, in the microbial cells. Low temperature in combination with a definite culture medium triggers the activity of certain enzymatic systems, which explains, to some extent, the biochemical mechanisms of the psychrophilic properties of Y. pseudotuberculosis.

Cell Division↗
PubMed1984

[Pathomorphology of experimental pseudotuberculous (Yersinia) arthritis].

Experimental pseudotuberculosis arthritis was reproduced by means of antigenic irritation of the knee joint in the presence of specific sensibilization. Pathomorphology is characteristic of the acute exudative-proliferative synovitis and periarthritis. The results obtained allow one to draw the conclusion on the infectious-allergic genesis of the joint involvement in pseudotuberculosis. The stages in the allergic responses of the synovial membrane with subsequent development of early and late immune inflammation are revealed.

Animals↗
PubMed1983

[Experimental basis for using Soviet bentonite clays as immunosorbents for serological studies].

The methodological principles of using Soviet bentonite clays as immunosorbents necessary for serological studies in bacterial infections were worked out. The method for the preparation of antigenic bentonite diagnostic reagents was experimentally substantiated. Bentonite diagnostic reagents were first used in a new method for the rapid indication of bacterial antigens in environmental objects with a view of solving epidemiological problems.

Adsorption↗