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The impact of a heat-stable toxin of Yersinia pseudotuberculosis (HSTYp) on the markers of functional activity and phenotypes of P1- and P2-type phagocytes was studied in the holothurian Eupentacta fraudatrix. In the control, P1 and P2 phagocytes differed in the levels of apoptosis and reduced glutathione, as well as in the surface receptor binding to some plant lectins. HSTYp (0.2–2 μg/mL) caused a shift in the functional activity and phenotype of P1 phagocytes toward the prevalence of those characteristic of the P2 type, which has a lower bactericidal activity. It is supposed that HSTYp is an important factor in the reprogramming of holothurian phagocytes toward the predominance of the anti-inflammatory type, which may increase the virulence of Y. pseudotuberculosis for holothurians.

The aim of the research is to distinguish and estimate the connection between the level of vegetative disfunction symptoms, factual biological age and the degree of adaptive potential of students.Materials and methods. Students with different symptoms of vegetative disfunction were engaged in the research. The factual biological human age was identified with the help of V.P. Vojtenko’s method and the degree of adaptive human potential was identified by R.M. Bajevsky method (1979). A standart questionnaire by А.М. Vein (1998) was applied to reveal the symptoms of vegetative changes. For the statistic analysis the method of questionnaire, statistics, mathematical, correlation and abstract methods have been used, as well as the method of deductive thinking and structuro-logical analylis in regards to the principles of systematics. All the questionnaire data received have been systematized and processed by the automatized method on a personal computer by using “Microsoft Office Excel 2010” and “Medstat”.Results. In the group of girls with vegetative disfunction the average value of factual biological age was 38,1±7,4 y., the average value of adaptive potential sustained correspondently 1,98±0,41 u.o. and the average value of questionnaire amounted in 34,06±13,78 p. Between the questionnaire data and the level of adaptive potential the coefficient of correlation was (r=+0,28, p 0,05). In the group of boys with the symptoms of vegetative disfunction the average value of factual biological age was 37,96±3,83 y., the average value of adaptive potential corresponded to 2,01±0,39 u.o. and the average value of the questionnaire sustained 29,4±8,26 p. There was a direct connection of average stength between the index of factual biological age and the adaptive potential of boys with the vegetative disfunction (r=+0,75). The coefficient of correlation between the data of questionnaire and the level of adaptive potential of boys of the first group amounts in -0,36, which shows the direct connection of average stength of the investigated symptoms. The veriability of the given result was not reliable. Veracious correlation connection between the factual biological age and the data of questionnaire of boys were not revealed. The veriability of the correlation connections in the control group of boys was not credible (p>0,05). In general, all the investigated boys and girls with the symptoms of vegetative disfunction had a direct correlation connection of average strength between the index of factual biological age and the questionnaire (r=+0,452, p

Electron microscopy study revealed changes in the ultrastructure of bacteria of Yersinia pseudotuberculosis strains characterized by significantly reduced reproductive ability and virulence potential after long-term storage at low temperature of 4-8°C. Most bacterial cells contained dark cytosol with reduced cellular material or empty cytosol, while the cell wall was preserved. The revealed ultrastructural changes in the bacterial cells of the static culture of Y. pseudotuberculosis suggest that storage of strains under low positive temperatures could induce the transition of the majority of bacterial cell population to a dormant, non-cultivated state with a decrease in their virulence. This fact is of great scientific and applied importance in studies of causative agents of saprozoonoses, including pseudotuberculosis, which has the etiopathogenetic background of persistent infection.

Cytotoxic necrotic factor (CNF) of Yersinia pseudotuberculosis (CNFY) is a 114-kDa toxin protein that is similar to CNF1, which is prevalent among pathogenic and saprophytic Escherichia coli isolates. In 2002, the CNF of Y. pseudotuberculosis YPIII strain (United States) was first described. The Rho family small GTP-binding proteins (GTPases) are inactivated by CNFY acting on eukaryotic cells of humans and mammals, which causes the formation of large multinucleated cells. An analysis of Y. pseudotuberculosis toxins isolated in Russia showed that the thermolabile toxin TLT described earlier was identified as identical to CNFY except for three amino acid substitutions. The TLT’s cytotoxic activity is similar to that of CNFY. Screening of Y. pseudotuberculosis strains collection isolated during the outbreaks of Far East scarletlike fever (FESLF) and in sporadic cases from patients with pseudotuberculosis/FESLF, rodents, and the environment in the Far East, Siberia, and the northwest of the Russian Federation showed that most isolates carry the specific cnfY gene allele encoding the inactive CNFY isoform. This allele contains a stop codon and two large deletions that block the production of the full-sized toxin. Interestingly, all isolates obtained from patients with FESLF, which is a severe form of pseudotuberculosis and endemic to the Far East region, contain inactivated CNFY. Possible causes of CNFY inactivation in strains associated with Far East scarletlike fever are discussed.

The effect of a thermostable toxin of Yersinia pseudotuberculosis (in comparison with that of dexamethasone) on the functional activities of two types of phagocytes (P1 and P2) was studied in the holothurian Eupentacta fraudatrix. A high level of NO was shown to be a marker of intact P1 cells, while the high activity of arginase was a marker of P2 cells. The antioxidant defense in the P1 type was more pronounced than that of the P2 type. At the same time, the toxin inhibited the functional activity (generation of reactive oxygen species) of P1 phagocytes after 1 h of incubation and induced primarily the activity of P2 phagocytes, compared to that of P1 cells, after 24 h. In contrast to dexamethasone, which induced the transformation of the P1 phenotype into the P2 phenotype, the toxin promoted the mutual acquisition of the phenotype features by these two types of phagocytes. An analogy between the P1 and P2 phagocytes of the holothurian and M1 and M2 macrophages is discussed.

Pseudotuberculosis is an acute infectious disease caused by Yersinia pseudotuberculosis. In the 1950 and 1960s, outbreaks of a new, previously unknown disease were registered in the Far East of Russia, called the “Far East scarletlike fever” (FESLF). FESLF is pseudotuberculosis, which has a specific clinical form. The disease is endemic to the Far Eastern, Siberian, and Northwestern regions of Eurasia. At present, there is only one system designed to detect Y. enterocolitis and Y. pseudotuberculosis for diagnostics by polymerase chain reaction. The disadvantage of this system is the lack of the possibility for the specific detection of Y. pseudotuberculosis. In this work, 35 strains of Y. pseudotuberculosis were characterized by the detection of the plasmid gene encoding the adhesin (yadA), MLST typing, and detection of the chromosomal gene of the Y. pseudotuberculosis—the cytotoxic necrotizing factor (cnfY). Detection of the yadA gene correlated with presence of the plasmid (pYV). The strains belonged to five MLST sequence types (STs), one of which, ST240, was described for the first time. All the studied strains of Y. pseudotuberculosis showed the presence of the cnfY gene. Additionally, the results of 68 previously described Y. pseudotuberculosis strains were analyzed. A total of 103 strains showed two allelic variants. Allele 1 was found in all strains isolated from patients with FESLF. The cnfY gene was not specifically associated with the presence of plasmids. The cnfY gene was absent in the Y. enterocolitica strains. Thus, the cnfY gene is a stable and specific marker of Y. pseudotuberculosis. On the basis of the obtained data, a PCR diagnostic system was developed for the detection and intraspecific differentiation of Y. pseudotuberculosis by determining the cytotoxic necrotizing factor gene in the biomaterial.

Maintaining cellular homeostasis in biological systems is the basic principle that ensures the functioning of organs and systems. At the cellular level, this process is regulated by genetically determined efferent signals. During evolution, biological systems developed hierarchically varying mechanisms of molecular genetic regulation of cell death. Numerous studies of extra- and intracellular mechanisms of programmed cell death (PCD) in eukaryotes have shown the complexity and the physiological selectivity of this phenomenon, which has been greatly important in medicine. In prokaryotes, the mechanisms and regulation of cell death have been studied less, but research of them has the great interest to characterize the existence of microbial communities. The aim of this review is to provide molecular genetic characteristics of cell death in prokaryotes based on available data.

Study of effect of heat-labile (HLT) and thermostable (HST) lethal toxins of Yersinia pseudotuberculosis on the development of embryos of sea urchin Strongylocentrotus intermedius, processes of biosynthesis of nucleic acids and protein in embryo cells and activity of nucleoside- kinases of sea urchin. Materials-and methods. Y pseudotuberculosis strains 2517 (pYV-) and 512 (pYV48MD, pYV82MD) were used for isolation of HLT and HST Gametes and embryos of sea urchin S. intermediuswere used to carry out the experiments and isolate nucleoside-kinases., Both of the studied toxins of Y pseudotuberculosis possessed, spermiotoxic effect and reduced fertilizing ability of sea urchin spermies. HLT LD₅₀ was 1 μg/ml, and HST - 2 μg/ml. Toxins affected the development of embryos of sea urchin resulting in severe morphologic damages, cessation ofthe development of embryos at early stages of embryogenesis, destruction of cells and death of embryos. Wherein; damaging effect of HLT was observed at lower concentrations compared with HST HLT inhibited DNA and RNA biosynthesis at concentrations of 1-2 μg/ml. HST did not affect biosynthesis of nucleic acids even at high concentrations, but inhibited protein biosynthesis in sea urchin embryos. HLT did not reduce the level of inclusion of labeled amino acids into embryo cells. HLT had inhibiting effect on the activity of thymidine- and uridine-kinase of sea urchin, whereas HST did not affect these enzymes.Both of Y pseudotuberculosis protein toxins affect the development of sea urchin embryos, however, mechanisms of action of HLT and HST on embryos and processes occurring in them differ.

We used multivirulence locus sequence typing to analyze 68 Yersinia pseudotuberculosis isolates from patients in Russia during 1973-2014, including 41 isolates from patients with Far East scarlet-like fever. Four genotypes were found responsible, with 1 being especially prevalent. Evolutionary analysis suggests that epidemiologic advantages could cause this genotype's dominance.

Sapronosis is an infectious disease caused by pathogenic microorganisms that are natural inhabitants of soil and/or aquatic ecosystems. They are capable of exiting in the environment outside of the host for a long time. Causative agents of sapronosis are polypathogenic, i.e., they cause infections in a wide range of hosts. The aim of the work was to establish a place in the clonal species structure for Listeria monocytogenes and Yersinia pseudotuberculosis isolated from both patients in hospitals and wild rodents and hydrobionts in natural foci. A total of 42 L. monocytogenes and 29 Y. pseudotuberculosis isolates were studied. 17 L. monocy-togenes and 29 Y. pseudotuberculosis isolates were obtained from patients; 25 L. monocytogenes isolates were obtained from wild animals and soil. The isolates were characterized using Multilocus Sequence Typing (MLST). Previously published MLST schemes were applied, including an analysis of the sequences of internal regions of seven marker genes for general metabolism. All Y. pseudotuberculosis isolates were shown to belong to the clonal complex occurred in the Russian Far East, Japan, and China, while L. monocytogenes isolates were referred to several clonal complexes, some of which have a worldwide distribution. The genetic similarity between L. monocytogenes isolates that cause invasive infections in wild animals in natural listeriosis foci and isolates related to listeriosis outbreaks has been demonstrated. These results suggested that high virulence could be a selective trait that enables the efficient reproduction of sapronosis causative agents in natural ecosystems. The variability of virulence factors of L. monocytogenes isolated from the same natural focus and related to MLST type was indicated. A hypothesis has been suggested that links the polyhostality of sapronosis causative agents and the genetic variability in virulence factors. Based on this hypothesis, a correlation has been suggested between the sequences of virulence factors and the source of isolation. A model of the formation of epidemiologically significant strains of the causative agents in natural foci of sapronosis was constructed.

Eighty-four isolates of Yersinia pseudotuberculosis obtained in the Russian Federation in 1967–2008 were examined. Most of the isolates (n = 55) were isolated from the feces of patients diagnosed with pseudotuberculosis (Far East scarlet-like fever), which was proven both clinically and serologically. Eighteen of these isolates were obtained during an investigation of three outbreaks of this disease in the Primorskii krai, nine were isolated from viscera of wild rodents, and the remaining isolates were obtained from environmental sources. Ten isolates of Yersinia pseudotuberculosis belonged to serovar III, while the remaining isolates belonged to serovar I. Sequencing of the inv gene 600 bp fragment that encodes invasin amino acids from 667 to 866 was performed for all isolates. Total, three allelic variants were identified. Allele 1 was the most frequent: 76 isolates carried this allele. In GenBank database, allele 1 is represented by the strain IP31758 derived from the Far East of the Russian Federation. Allele 2 differed from allele 1 in three positions, i.e., G2299C, T2300C, and T2302C. Mutations at positions 2299 and 2302 were nonsynonymous and led to substitutions Ser768Thr and Val769Ala in the protein sequence. Six isolates carried allele 2, allele 3 differed from allele 2 by a single synonymous substitution G2324T, and two strains carried allele 3. The latest allelic variant was inherent in the inv gene sequence of Y. pestis strains accessible in the GenBank database. Allele distribution was serovar-independent; Yersinia pseudotuberculosis serovar III and most of serovar I isolates carried allele 1. Allele distribution was independent of the region where the isolates were obtained. Yersinia subpopulations from different origins (derived from different sources of isolation) differed significantly; e.g., bacteria isolated from rodents differed significantly from clinical and environmental isolates (p < 0.05). Allele 1 predominated in isolates obtained from patients (95%); among the rodent isolates, the frequencies of alleles 1 and 2 were similar (55 and 45%, respectively).

The effect of Yersinia pseudotuberculosis, the bacterial pathogen affecting humans and animals, on growth of ginseng (Panax ginseng C.A. Mey) cell cultures was studied. The bacteria strongly induced the expression of phenylalanine ammonia-lyase and β-1,3-glucanase, the proteins encoded by the defense-related genes of ginseng and inhibited the normal ginseng callus growth but did not affect the resistant cell cultures. The thermostable and thermolabile protein toxins of these bacteria are lethal to mice when induced parentherally, and they also induced the expression of the defense-related genes in ginseng callus cultures. At the same time, the ginseng cells completely suppressed the bacterial cell growth. These data suggest that the ginseng cells recognized the yersinia and developed the immune response to this pathogen. The interaction between the ginseng cells and Y. pseudotuberculosis is similar to the hypersensitive response of plants to plant pathogens.

Pure fraction (92%–95%) of phagocytes (FP) and a mixture of amoebocytes (62%) and morula cells (38%)-FPMC- of the holothurianEupentacta fraudatrix' (Holothuroidea, Dendrochirota) were obtained by using ficoll-verographine step gradient. Basal production of reactive oxygen species (ROS) in FP quantified by using reduction of nitroblue tetrazolium (NBT) was more than twice that in FPMC. Thermostable toxin ofYersinia pseudotuberculosis (TST) at different concentrations (0.2; 0.5; 2.5 μg/ml, but not 0.1 μg/ml) stimulated NBT reduction in FPMC after 24 h incubation. In FP, TST at concentrations of 0.1 and 0.2 μg/ml inhibited and at concentrations of 0.5 and 2.5 μg/ml stimulated NBT reduction after 24 h incubation. Maximal effect was observed in FP and FPMC at TST concentrations of 0.5 and 0.2 μg/ml, respectively. Addition of catalase (0.7 μg/ml) to the cells treated with TST (2.5 μg/ml) was followed by a decrease in NBT reduction compared to that under toxin treatment alone. TST stimulated superoxide dismutase activity in concentration-dependent manner (maximum at 0.5 μg/ml concentration in FP) after 24 h treatment, and this stimulation was prevented by a commercial catalase. Plant lectin concanavalin A stimulated NBT reduction more than 5-fold in FPMC compared to the control. With addition of TST, lectin stimulated ROS to lesser extent than that with lectin alone. When catalase, TST, and lectin were added into the FPMC simultaneously, ROS increase was similar to that under lectin treatment alone. On the whole, data obtained indicated that ROS generation in holothurian coelomocytes especially occurs in both stimulated and not stimulated phagocytes, and that changes in ROS production by these cells may be one of the mechanisms of antibacterial protection of holothurians.

Pathogenic properties of thermostable toxin responsible for pathogenicity ofYersinia pseudotuberculosis were experimentally studied. The toxin exerted a pronounced polyorgan cytopathogenic effect with predominating degenerative destructive changes and membranolytic effect on cell ultrastructure of parenchymatous organs. The toxin is believed to be directly involved in the development of typical pathomorphological picture of pseudotuberculosis, which confirms its pathogenetic role.

The thermolabile toxin of Yersinia pseudotuberculosis produces a selective dose-dependent stimulating effect on functional activity of innate immunity cells. Prolonged apoptosis-inducing action of the toxin was associated with activation of enzymes of the oxygen-dependent system (LDH and myeloperoxidase) at the early terms of observation (up to 3 h). In turn, increased number of macrophages with apoptotic changes was noted at the early stages of contact with the thermolabile toxin (5 h), and its further growth was observed against the background of activation of mitochondrial enzymes and production of NO metabolites.

Pathogenesis of the disease caused by Yersinia pseudotuberculosis is associated with the production of a set of toxins. The plasmid-encoded YopE toxin and the chromosome-encoded cytotoxic necrotizing factor (CNF) modify the activity of small GTPases of the Rho family, inducing multiple changes in the target host cell. The variability in the YopE and CNF domains involved in protein–protein interactions with small Rho GTPases was studied in 33 strains isolated from patients clinically diagnosed with Far East scarlet-like fever (FESLF) and from environmental sources in Russia. All FESLF-associated strains and the majority of environmental strains carried the same yopE allele. The allele differed from alleles described in European isolates by a single nonsynonymous substitution. A distinct allele with two nonsynonymous substitutions was found in a single environmental strain. All but one strain had a deletion in the cnf gene. The deletion caused a total loss of the Rho-binding domain of CNF. Our results demonstrate that the yopE gene is highly conserved and suggest that CNF toxin is not involved in the regulation of GTPase activity in Y. pseudotuberculosis strains isolated in Russia.

Evaluation of immunogenic and protective properties of constructs based on subunit porin antigen from Yersinia pseudotuberculosis, immunostimulating complexes (ISCOM) and tubular immunostimulating (TI) complexes.Porin antibodies and blood serum cytokines were determined by using EIA. Porin-specific cell immunity was evaluated by DTH reaction inflammation index. Protective activity of porin formulations was determined by measuring specific gravity of animals surviving Yersinia pseudotuberculosis lethal challenge.Porin in TI complexes develops higher immunogenicity when compared with individual protein or protein with complete Freunds adjuvant. Porin in TI complexes develops higher protective activity, inhibits interferon synthesis in mice. Incorporation of porin into TI complexes results in neutralization of porin suppressive activity against DTH mechanisms and interferon system.TI complexes may be used as perspective carriers for bacterial antigens. TI complexes have adjuvant properties and can provide protective properties to porin vaccine constructs.

A total of 84 Y. pseudotuberculosis isolates were studied. The isolates were obtained in Russian Federation in 1967-2008. The majority of Y. pseudotuberculosis isolates (n = 55) were of clinical origin and were isolated from feces of patients with the clinically and serologically proved diagnosis of pseudotuberculosis/Far East scarlet-like fever. These isolates included 18 isolates obtained from 3 outbreaks. Nine isolates were isolated from the internal organs of wild rodents. Other isolates were obtained from environmental sources. Ten Y. pseudotuberculosis isolates belonged to the serovar III and the other isolates belonged to the serovar I. The sequences of 600 b.p. fragment of the inv gene that encodes 667 through 866 invasin amino acids were determined for all isolates. Totally, 3 allelic variants were found. The most abundant allele 1 was found in 76 isolates. The allele 1 is represented in the database Genbank by the strain IP31758 isolated in the Far East of Russia (Eppinger et al., 2007). The allele 2 differed from allele 1 in 3 positions: G,2299N, O2300N, and O2302N. Substitutions in positions 2299 and 2302 were non-synonymous and resulted in amino acid substitutions Ser768 Thr and Val769 Ala. Six isolates carried allele 2. Allele 3 was found in two isolates different from allele 2 by a synonymous substitution G2324O. This allele is similar to the sequence found in Y. pestis strains, represented in the GenBank. The allelic distribution was not serovar specific: Y. pseudotuberculosis of serovar III and majority of serovar I isolates carried allele 1. The analysis of the allelic distribution among subpopulations formed on the base of a source of isolation revealed a statistically significant difference in spreading of alleles among clinical and wild rodent isolates (p0.05). Allele 1 prevailed over clinical isolates (95%), while allele 1 and allele 2 were disseminated equally among rodent isolates (55 % and 45 %, respectively).

Influence of thermolabile lethal toxin of Y. pseudotuberculosis on the development of embryos of sea urchin (Strongylocentrotus intermedius) and on biosynthesis of nucleic acids in embryonic cells was studied. Thermolabile lethal toxin affected metabolic processes of cells by inhibiting DNA and RNA synthesis. It had damaging action on developing embryos of sea urchin causing morphological changes and, as a consequence, death of embryos.

The aim of the study was to assess the biological properties of heat-labile lethal protein toxin of Y. pseudotuberculosis. Toxin was extracted from Y. pseudotuberculosis strain 2517 type III serovar pYV-. The toxin killed mice 1-3 days after intraperitoneal administration (LD50=0.3 mcg of the protein). Heating at 56 degrees C during 30 min inactivated lethal activity of the toxin. It had a dose-dependent dermonecrotic effect during intracutaneous administration in rabbits. Hyperimmune rabbit serum to the toxin was obtained. Incubation of the toxin (LD100=1.2 mcg of the protein) with the serum at 37 degrees C during 30 min resulted in neutralization of lethal and dermonecrotic effects. The toxin did not have the cytotoxic effect on HeLa, Hep-2, and SPEV cells, but showed hemolytic activity to human and animal erythrocytes, and weak mitogenic activity to splenic cells of CBA line mice compared with control mitogen (concanavalin A).

The review of publications about protein toxins Y. pseudotuberculosis are presented. It includes the main data obtained by domestic and foreign investigators as well as the results of our own elaboration in the study of Y. pseudotuberculosis protein toxins. The guestions of isolation, purification, characterization of physico-chemical and biological properties, the mechanism action and role of toxins on pathogenesis of infection were discussed.

The therapeutic effect of a Polar shark cartilage preparation which is an enzymatic hydrolysate was studied in a rabbit model of infective allergic pseudotuberculous arthritis. Characterization of the chemical composition of the preparation designed by an original method is presented. Improvement of the general state of the affected joints and development of tissue immunomorphological responses were shown.

The effect of low molecular DNA from salmon milt (nDNA) in experimental pseudotuberculosis in mice was studied. When nDNA was admiministered orally, dissemination of the organs by Yersinia pseudotuberculosis lowered and the survival of the animals infected with 100-percent lethal dose of the bacteria increased. nDNA decreased contamination of the epithelial cells by the microbe in vitro and prevented the lethal effect of the Y. pseudotuberculosis toxins on the mice.

Enzyme capable of catalyzing the phosphorylation of thymidine and uridine was isolated from Y. pseudotuberculosis cells by fractionation with the use of ammonium sulfate, ion exchange and affinity chromatography. The degree of purification of thymidine- and uridine-kinase was approximately 350 times, and at all stages of isolation the activity of both nucleoside-kinases was detected in the same peaks. The purified enzyme was capable of the phosphorylation of thymidine and uridine at temperatures of 8-10 degrees C to 50 degrees C and exhibited the maximum enzymatic activity at pH 8-8.5 and 45 degrees C in the presence of 0.5-1.0 mM MgCl2 and 2 mM ATP. The enzyme was found to have no strict substrate specificity and transferred the phosphate group from ATP to radiolabeled thymidine, uridine and desoxycytidine with different effectiveness, but did not use thymidine-monophosphate as phosphate acceptor.

The results of the in vitro action of Y. pseudotuberculosis heat stable lethal toxin on the biosynthesis of protein are presented. The toxin was shown to inhibit the inclusion of exogenous amino acid into newly synthesized peptides. The degree of the inhibition of the biosynthesis of protein in the in vitro system depends on the amount of the toxin added to the incubation mixture. The use of the conjugated transcription and translation system confirms our earlier data on the influence of the lethal toxin on the biosynthesis of protein in eukaryotic cells in vivo.

Under experimental conditions within the time limit of 21-35 days the causative agents of sapronotic infections in binary cultures, grown on a solid medium at 37 degrees C, 25-27 degrees C and 6-8 degrees C, interacted with one another transbiotically and through contact, their interactions having the character of amensalism, commensalisms-amensalism, competitive equilibrium, antibiosis. Irrespective of the initial density, a change in the species composition was observed, one of them playing the dominating role. At 37 degrees C mutual antagonism of Yersinia pseudotuberculosis and Pseudomonas aeruginosa killed both cultures. P. aeruginosa cells were also killed when cultivated at 37 degrees C jointly with Listeria monocytogenes, the most resistant species under experimental conditions. While studying the character of microorganisms interactions the method of contacting cultures on a solid medium was shown to give more information in comparison with the "cross-strip" method. Possible interspecific relationships between the causative agents of sapronotic infections under natural conditions are discussed.

The ability to correct activity of Y. pseudotuberculosis thermoresistant toxin on antioxidative enzymes and on active oxygen forms in neurophiles and mononuclears was investigated. Toxin at concentration 0.5 and 2.5 mcg/ml did not change O2- production and activity of superoxidedismutase (SOD) and glutathione peroxidase (GP), but significantly enhanced catalase and glutathiont reductase (GR) activity. Gangleen at concentration 0.0002-0.2 mcg/ml, when added to incubation medium with toxin, stimulated production of active oxygen forms and activity of SOD, catalase, GP in both types of leucocytes, but decreased activity of GR in mononuclears. The results of investigation proves the ability to use gangleen in correction of immune system disorders caused by Y. pseudotuberculosis thermoresistant toxin.

Y. pseudotuberculosis cells cultivated at temperatures of 37 degrees C and 8 degrees C were found to be capable of incorporating exogenic precursors into DNA, RNA and protein. The linear growth of thymidine incorporation occurred during 8 hours of cultivation at 37 degrees C, then the amount of the incorporated label decreased. At 8 degrees C the level of thymidine incorporation into DNA gradually increased for 80 hours and longer, but not reaching the level of incorporation observed at 37 degrees C. The incorporation of uridine into RNA of Y. pseudotuberculosis cells reached its maximum after 4 hours of cultivation at 37 degrees C, at a lower temperature of cultivation the incorporation of uridine into bacterial cells was almost linear, though slower, and lasted for 20 hours. The content of radioactive alanine in Y. pseudotuberculosis protein increased during 16 hours of cultivation at a high temperature, while at 8 degrees C the growth of the incorporation level lasted for at least 40 hours. For all precursors under study the incorporation rate into the cell biopolymers at the initial stages of cultivation was higher at 37 degrees C, than at a lower temperature.

Pathogenic properties of thermostable toxin responsible for pathogenicity of Yersinia pseudotuberculosis were experimentally studied. The toxin exerted a pronounced polyorgan cytopathogenic effect with predominating degenerative destructive changes and membranolytic effect on cell ultrastructure of parenchymatous organs. The toxin is believed to be directly involved in the development of typical pathomorphological picture of pseudotuberculosis, which confirms its pathogenetic role.

Y.pseudotuberculosis thermostable lethal toxin as shown to affect the functional activity of human blood leukocytes. Still neutrophils and monocytes exhibited different reaction to the introduction of the toxin. In monocytes, the toxin in a dose of 0.2 microgram/4 x 10(4) cells inhibited the formation of active forms of oxygen (AFO) and activated the production of superoxide dismutase (SOD). In neutrophils, the toxin affected only the activity of glutathione reductase, inducing a decrease in its activity. The toxin, depending on its dose, stimulated a rise in the level of cyclic adenosine monophosphate (cAMP) in mononuclear cells, but inhibited it in neutrophils. When the toxin was introduced together with indomethacin (10(-7) M), the level of cAMP increased in mononuclears and decreased in neutrophils in comparison with the action of the toxin, introduced alone. Indomethacin prevented the action of the toxin on mononuclears with respect to AFO, SOD and cAMP, which was indicative of the mediating role of prostaglandins in the mechanism of the action of the toxin.

Under the conditions of a prolonged experiment in sterile water at 4-6 degrees with no outside supply of any substances pathogenic Y.pseudotuberculosis, Y.enterocolitica and other Yersinia species in pure and binary cultures remained viable for the period of 12-24 months (the term of observation). In monocultures, all Yersinia actually returned to their initial amounts. In associations with Y.enterocolitica O:3, Y.frederiksenii and Y.intermedia, a delay in the lag-phase (1-2 weeks) was observed in Y.pseudotuberculosis, while in the other pair they stimulated the lag- and log-phase in Y.enterocolitica O:8. In other associations, the growth of different cultures was balanced; 12 and 24 months later their amount characteristics exceeded the initial ones by 2-4.9 and 1-3.5 orders respectively. The possibility of interaction with the signs of protocooperation between different Yersinia cells under natural conditions is discussed.