[Management of the patient with renal artery fibromuscular dysplasia: clinical case]

Fibromuscular dysplasia (FMD) is a rare disease that affects small and medium-sized arteries. Clinical manifestations of FMD depend on its localization. In many cases, FMD of renal arteries (RA) is associated with arterial hypertension. Young age, particularly of female patients, suspected RA dissection or kidney infarction, absence of atherosclerosis or presence of FMD in other arteries of such patients evidence for RA FMD. In invasive treatment of hemodynamically significant stenoses, transluminal balloon angioplasty (TBA) of renal arteries is preferrable. Taking into account initial alterations of the vascular wall and unevenness of the lumen of the affected blood vessel, stent implantation is associated with an increased risk of complications and is recommended only if ballooning complications develop. An open reconstructive surgery is indicated in complicated narrowing anatomy, a high risk of the endovascular treatment, or after failure of the endovascular intervention. This article presents a clinical case of a young female patient with RA FMD and renovascular arterial hypertension who successfully underwent renal TBA with a drug-coated balloon.

Clinical and prognostic significance of the soluble form of the VISTA immunity control point in patients with primary bone tumors

The data of a comparative enzyme-linked immunosorbent assay of the content of the soluble form of the immunity checkpoint VISTA in the blood serum of 30 healthy donors (control group), 79 patients with primary malignant (osteosarcoma - 30, chondrosarcoma - 31, chordoma - 14) and 14 borderline (giant cell tumor) bone neoplasms are presented. In the general group of patients with malignant neoplasms of bones, the median sVISTA content in blood serum is statistically significant lower than in the control (p = 0.040). In patients with bone tumors and healthy donors over 18 years of age, there was a decrease with age in serum sVISTA levels. There were no significant differences in sVISTA concentration between patients with osteosarcoma, chondrosarcoma and healthy donors. Only in patients with chordoma were sVISTA levels statistically significant lower than in controls (p = 0.013). In the groups of patients with chondrosarcoma and osteosarcoma of the bone, there were no significant associations between the serum sVISTA content and the main clinical and morphological characteristics of the disease. In patients with osteosarcoma, no relationship was found between sVISTA levels and overall survival rates, while in patients with bone chondrosarcoma, there was a tendency towards a favorable prognosis with a high content of the marker in the blood serum.

[Developmental dysphasia and epileptiform EEG activity in children]

Objective. To study the electrical activity of the brain in children with developmental dysphasia (alalia). Material and methods. We analyzed the EEGs of 65 children with developmental dysphasia, including 48 boys and 17 girls, aged from 3 to 4 years 11 months. General speech underdevelopment (GSU) of the 1st level (with active vocabulary less than 15-20 words) was found in 31 children and GSU of the 2nd level (with active vocabulary of 20-50 words) - in 34 children. To specify the changes in the brain electrical activity, we conducted video-EEG-monitoring during sleep and waking states in 27 patients. Results. Focal epileptiform EEG changes with no concomitant paroxysmal symptoms were recorded in 12,3% of children with dysphasia. The epileptiform activity was more frequent in GSU of the 1st level (5 (16.1%) patients) than in GSU of the 2nd level (3 (8.8%) patients). Benign epileptiform discharges of childhood with low index were identified in 2 (6,5%) children with GSU of the 1st level and in1 (2,9%) child with GSU of the 2nd level; low index spike-waves were recorded in 3 (9,7%) children with GSU of the 1st level and in 2 (5,9%) with GSU of the 2nd level. Conclusion. The data allow to clarify the frequency of epileptiform EEG activity in those children with developmental dysphasia, who do not have autism or history of seizures. The differential diagnosis with rare epileptic encephalopathies is needed, such as epilepsy with electrical status epilepticus during slow sleep (ESES) and Landau-Kleffner syndrome.

[Developmental dysphasia in children: perspectives of neurotrophic therapy]

Developmental dysphasia (alalia) represents a severe speech and language disorder in children. To assess the efficacy of treatment with cerebrolysin, we have examined 60 children with developmental dysphasia, aged from 3 to 4 years. Group 1 (30 patients) received cerebrolysin (monotherapy, daily dosage 0.1 ml/kg, in the morning hours, on each other day, i.m., 30 injections in total) during 2 months. Group 2 (controls, 30 patients) did not receive pharmacotherapy. A significant improvement of expressive, impressive speech and speech attention was observed in group 1 after the treatment. The active vocabulary increased by a factor of 3.5 and phrases number in colloquial speech by a factor of 5, versus 1.5 in the control group. According to parents' questionnaires, the treatment resulted in the decrease of psychasthenic, psychosomatic problems, motor clumsiness and hyperactivity along with the improvement of attention, emotional control and behavioral measures. The positive effect of cerebrolysin on the motor development was demonstrated by the assessment of motor milestones.

[Developmental dysphasia: assessment of the drug treatment efficacy]

To assess the efficacy of treatment with encephabol, we examined 40 children, aged from 3 to 5 years, with developmental dysphasia. All patients were randomized into two equal groups: group 1 received encephabol (suspension form, daily dosage 200-250 mg, or 12-15 mg/kg) during 2 months; group 2 did not receive this medication. In the first group, there was a significant improvement of expressive and impressive speech and speech attention; the active vocabulary and a number of phrases in colloquial speech increased by a factor of 3 versus 1.5 in the control group. After the treatment with encephabol, the parents reported the decrease in motor disturbances, psychosomatic disorders, the improvement of attention and the emotional state of the children.

Comparative Global Gene Expression Profiles of Wild-Type Yersinia pestis CO92 and Its Braun Lipoprotein Mutant at Flea and Human Body Temperatures

Braun/murein lipoprotein (Lpp) is involved in inflammatory responses and septic shock. We previously characterized a Deltalpp mutant of Yersinia pestis CO92 and found that this mutant was defective in surviving in macrophages and was attenuated in a mouse inhalation model of plague when compared to the highly virulent wild-type (WT) bacterium. We performed global transcriptional profiling of WT Y. pestis and its Deltalpp mutant using microarrays. The organisms were cultured at 26 and 37 degrees Celsius to simulate the flea vector and mammalian host environments, respectively. Our data revealed vastly different effects of lpp mutation on the transcriptomes of Y. pestis grown at 37 versus 26 degrees C. While the absence of Lpp resulted mainly in the downregulation of metabolic genes at 26 degrees C, the Y. pestis Deltalpp mutant cultured at 37 degrees C exhibited profound alterations in stress response and virulence genes, compared to WT bacteria. We investigated one of the stress-related genes (htrA) downregulated in the Deltalpp mutant relative to WT Y. pestis. Indeed, complementation of the Deltalpp mutant with the htrA gene restored intracellular survival of the Y. pestis Deltalpp mutant. Our results support a role for Lpp in Y. pestis adaptation to the host environment, possibly via transcriptional activation of htrA.

[The effect of 2,4-dinitrophenol on the intensity of oxidative processes in the rat liver during prolonged experiment]

The effect of uncoupler 2,4-dinitrophenol on the oxidative processes intensity in liver biomembranes of different age and sex of rats during longitudinal experiment was studied. It was established that 2,4-dinitrophenol in the used concentration hadn't essential negative effect on the organism of females and their posterity. On the young, 3-3,5-month old males it was shown that long-term xenobiotic administration had been accompanied by intensification of the rate of oxygen consumption, decrease of the rate of reactive oxygen species formation in microsomal redox-chain, decline in lipid hydroperoxides and protein carbonils levels in blood serum and liver microsomes, and also by increase of their mean lifespan. The obtained results may testify the possibility of correction of oxidative processes intensity in tissues of mammals and their lifespan by means of modulation of membrane electron transport chains activity.

[Gingival tissues age- and gender-specific peculiarities in healthy conditions and in cases of chronic apical periodontitis]

By light microscopy there was studied gingival tissues structure depending upon age and gender in 96 relatively healthy persons and 80 patients with chronic apical periodontitis. It was disclosed that in gingival mucosa of patients with chronic apical periodontitis the interstitial space volumetric density and numerical density of tissue leucocytes increased in the first place due to neutrophils. Between the healthy men and women there was no significant difference in structural organization of the gum as well as between the patients of different gender. The only sign was that in healthy men and women with age progressing only lymphatic vessels area decreased on gingival mucosa microscopic section. In patients with chronic apical periodontitis both blood and lymphatic vessels were involved through decrease of relative capillary density.

[B-cellular lymphoid follicles of gingival mucous membrane in cases of chronic apical periodontitis]

The structure of gingival mucous membrane leukocytal infiltration of 80 patients with chronic apical periodontitis of different age groups was studied by the light microscopy with the use of monoclonal antibodies to CD38. It was disclosed that in gingival tissues of practically all patients 2 types of leukocytal infiltration were present with low number of plasmatic cells and high number of neutrophils (true leukocytal infiltration) and structures with high number of plasmatic cells and low number of neutrophils - most likely lymphoid follicle resultant in mucous membranes of different organs in cases of chronic inflammation. In epithelial gingival paving in cases of chronic apical periodontitis CD38(+)-cells were absent.

[Formation of plasma cell infiltrates in gingiva of patients with chronic apical periodontitis]

The structure of leukocyte infiltrates in gingiva of 80 patients of various ages and gender with chronic apical periodontitis was studied using light microscopy with the application of monoclonal antibodies detecting CD38 antigen. Gingival tissues of practically of all the patients with periodontitis contained 2 types of leukocyte infiltrates: infiltrates with the low plasma cell content and high numbers of neutrophils and structures with high number of plasmocytes and low concentration of neutrophilic granulocytes. Within the gingival epithelium in patients with chronic apical periodontitis CD38 + cells were absent. The histogenesis of gingival leukocyte infiltrates in chronic apical periodontitis is discussed with the special emphasis on the role of plasma cells in the development of the pathological process.

[The protein oxidative damage level and lifespan modulation by xenobiotics in Drosophila melanogaster]

The effect of xenobiotics on protein oxidative damage and lifespan of Drosophila melanogaster Meig., line Oregon-R, was studied. Addition of the uncoupler 2,4-dinitrophenol (DNP) to the nutritional mixture results in an induction of synthesis of heat shock proteins and increase of lifespan of insects, whereas sodium nitroprusside (SNP) has negative effect on flies viability connected, probably, with activation of processes of proteins oxidative damage. It is shown that DNP essentially corrects the SNP negative action on insects' survival rates and this "normalizing" action is revealed both at a level of sensitivity of flies to exogenic stresses and protein carbonils level and at a level of insects lifespan as a whole. It is supposed that DNP protects from SNP negative action on flies viability by reduction of intensity of free radicals production and/or induction of heat shock proteins synthesis. Consequence of that is reduction of oxidative proteins damage degree and increase of survival rate (life span) of flies.

Molecular characterization of a glucose-inhibited division gene, gidA, that regulates cytotoxic enterotoxin of Aeromonas hydrophila

By using a mini-transposon, we obtained two mutated strains of a diarrheal isolate, SSU, of Aeromonas hydrophila that exhibited a 50 to 53% reduction in the hemolytic activity and 83 to 87% less cytotoxic activity associated with the cytotoxic enterotoxin (Act). Act is a potent virulence factor of A. hydrophila and has been shown to contribute significantly to the development of both diarrhea and septicemia in animal models. Subsequent cloning and DNA sequence analysis revealed that transposon insertion occurred at different locations in these two mutants within the same 1,890-bp open reading frame for the glucose-inhibited division gene (gidA). A similar reduction in hemolytic (46%) and cytotoxic (81%) activity of Act was noted in the gidA isogenic mutant of A. hydrophila that was generated by marker exchange mutagenesis. Northern blot analysis revealed that the transcription of the cytotoxic enterotoxin gene (act) was not altered in the gidA transposon and isogenic mutants. However, by generating a chromosomal act::alkaline phosphatase gene (phoA) reporter construct, we demonstrated significantly reduced phosphatase activity in these mutants, indicating the effect of glucose-inhibited division (GidA) protein in modulating act gene expression at the translational level. The biological effects of Act in the gidA mutants were restored by complementation. The virulence of the gidA mutants in mice was dramatically reduced compared to the those of the wild-type (WT) and complemented strains of A. hydrophila. The histopathological examination of lungs, in particular, indicated severe congestion, alveolar hemorrhage, and acute inflammatory infiltrate in the interstitial compartment and the alveolar spaces when mice were infected with the WT and complemented strains. Minimal-to-mild changes were noted in the lungs with the gidA mutants. Taken together, our data indicate for the first time that GidA regulates the most-potent virulence factor of A. hydrophila, Act.

Role of various enterotoxins in Aeromonas hydrophila-induced gastroenteritis: generation of enterotoxin gene-deficient mutants and evaluation of their enterotoxic activity

Three enterotoxins from the Aeromonas hydrophila diarrheal isolate SSU have been molecularly characterized in our laboratory. One of these enterotoxins is cytotoxic in nature, whereas the other two are cytotonic enterotoxins, one of them heat labile and the other heat stable. Earlier, by developing an isogenic mutant, we demonstrated the role of a cytotoxic enterotoxin in causing systemic infection in mice. In the present study, we evaluated the role of these three enterotoxins in evoking diarrhea in a murine model by developing various combinations of enterotoxin gene-deficient mutants by marker-exchange mutagenesis. A total of six isogenic mutants were prepared in a cytotoxic enterotoxin gene (act)-positive or -negative background strain of A. hydrophila. We developed two single knockouts with truncation in either the heat-labile (alt) or the heat-stable (ast) cytotonic enterotoxin gene; three double knockouts with truncations of genes encoding (i) alt and ast, (ii) act and alt, and (iii) act and ast genes; and a triple-knockout mutant with truncation in all three genes, act, alt, and ast. The identity of these isogenic mutants developed by double-crossover homologous recombination was confirmed by Southern blot analysis. Northern and Western blot analyses revealed that the expression of different enterotoxin genes in the mutants was correspondingly abrogated. We tested the biological activity of these mutants in a diet-restricted and antibiotic-treated mouse model with a ligated ileal loop assay. Our data indicated that all of these mutants had significantly reduced capacity to evoke fluid secretion compared to that of wild-type A. hydrophila; the triple-knockout mutant failed to induce any detectable level of fluid secretion. The biological activity of selected A. hydrophila mutants was restored after complementation. Taken together, we have established a role for three enterotoxins in A. hydrophila-induced gastroenteritis in a mouse model with the greatest contribution from the cytotoxic enterotoxin Act, followed by the Alt and Ast cytotonic enterotoxins.

[Effect of arsenite on the physiological and cytological properties of Pseudomonas putida strains capable of degrading polycyclic aromatic hydrocarbons]

Some physiological and cytological properties of Pseudomonas putida strains resistant to arsenite and capable of degrading polycyclic aromatic hydrocarbons were studied. The resistance of P. putida BS202 (NPL-1) to arsenite proved to be determined by chromosomal genes, while the arsenite resistance of P. putida BS238 (pBS2; pBS3031) was by plasmid-borne genes. Arsenite affected the pattern and rate of growth of strain BS202 (NPL-1) in media with naphthalene or salicylate as carbon sources; particularly, it lengthened the lag phase. Electron-microscope analysis of the strains studied did not reveal any arsenite-induced destructive changes in the cell envelope. At the same time, arsenite in the growth medium induced some alterations in the structure of the outer membrane of strain BS202 (NPL-1) and the cytoplasmic membrane of strain BS238 (pBS2; pBS3031) and, in both strains, led to an increase in the density of intramembrane particles on the EF face of the freeze-fractured cytoplasmic membrane. Arsenite resistance probably evidently protects cells of both strains from greater damage. Physiological and cytological data suggest that the mechanisms of arsenite resistance in the strains studied are different.

[Effect of paracetamol on the microsomal oxidation, oxidative phosphorylation and liver mitochondria swelling in rats of various ages]

The effect of hepatotoxic dose of paracetamol (800 mg per kg, intraperitoneally, once a day during two days) on the system of microsomal oxidation, respiration, oxidative phosphorylation and high amplitude swelling of liver mitochondria was studied on 1-, 4- and 30-months old Wistar male rats. It has been shown, that paracetamol injection leads to the decrease of content of cytochrome P-450, to disorders of the function of monooxygenase system (the aminopyrine-N-demethylase and aniline hydroxylase activities were diminished), mitochondria macrostructure (the mitochondria high amplitude swelling time was decreased) and function (the respiratory control was decreased). These alterations have been observed to manifest to more extent in the liver of young rats as compared with old ones.

[Cloning and expression of a plasmid pBS195 gene, determining oxygenase activity, in Escherichia coli cells]

Plasmid pBS195, detected in a strain of Lactobacillus sp. isolated from long-living persons, has a broad host range, including Gram-positive and Gram-negative microorganisms [1]. Plasmid-harboring colonies of the strain Escherichia coli HB101 give a color reaction with catechol. This indicates that genes mediating the activity of oxygenase are present in this plasmid. The high activity level of this enzyme, mediated by pBS195, and substrate specificity, which has not bee detected in any known metapyrocatechases, were found in cells of E. coli. Hybridization with a 32P-labeled fragment containing the NahC gene revealed a region of homology with a 1.6-kb EcoR I- BamH I fragment of plasmid pBS195. Deletion variants of this plasmid that lost oxygenase activity confirmed the location of the oxygenase gene in this region. The gene responsible for oxygenase activity in the plasmid was cloned on the pUC19 vector in E. coli cells. The expression of the cloned gene is controlled by the lac promoter of this vector. Physical, hybridization, and deletion analyses as well as analysis of polypeptides, which are synthesized in E. coli mini-cells, showed that this activity requires the participation of a polypeptide with molecular mass of 34 kDa.

[Structure-functional characteristics of pBS195 plasmids from a broad range of gram-positive and gram-negative hosts]

The ability of plasmid pBS195 to be inherited by a broad host range including both gram-positive and gram-negative bacteria attracts special attention to its molecular genetic organization. Physical map of the plasmid has been constructed and the gene for kanamycin resistance and oriV homologous to the one of pUC19 have been localized. The determinants for kanamycin-resistance have been shown to share no homology with the genes for the I and II type phosphotransferases and type II nucleotide-transferase. The minicells of Escherichia coli x925 harboring pBS195 produce two plasmid-encoded proteins with mol. masses 26 and 34 kD found in SDS-PAGE. The plasmid determines an oxygenase activity and shares homology with a nahC gene in the EcoRI-BamHI region (0 bp-1.6 kbp). The enzyme was identified as a methylpyrocatehase possessing high activity in Escherichia coli cells and substrate specificity uncharacteristic of this type enzymes.

[Genetic control of tetracycline resistance in bacteria]

Modern data on prevalence, structural and functional organization of the tetracycline resistance determinants in bacteria are reviewed. The three mechanisms of the antibiotic resistance are the tetracycline efflux, the ribosomal protection and the antibiotic modification. The problems of evolution of tetracycline resistance genes are discussed.

[Regulation of the catalytic activity and supermolecular structure of penicillin acylase from Escherichia coli in an aerosol OT reversed micelle system in octane]

The properties of penicillin acylase from E. coli solubilized by hydrated reversed micelles of Aerozol OT (AOT) in octane were studied. The catalytic activity dependence on the hydration degree, a parameter which determines the size of the micelle inner cavity, represents a curve with three optima, each corresponding to the enzyme functioning either in a dimer form (omega 0 = 23) or in the form of separate subunits--heavy, beta, and light, alpha, at omega 0 = 20 and 14, respectively. Reversible dissociation of the enzyme was confirmed by ultracentrifugation followed by electrophoresis. Preparative isolation of penicillin acylase subunits, their catalytic activity being retained, was shown to be possible.

[Antibiotic resistance of Lactobacillus strains]

One hundred and thirty six Lactobacillus strains isolated from poultry and 23 Lactobacillus strains isolated from long-living persons were tested for their antibiotic sensitivity. Occurrence of some type determinants of resistance to aminoglycoside antibiotics and tetracyclines in the Lactobacillus strains resistant to these antibiotics was studied. The majority of the strains from the both collections were resistant to aminoglycosides (73 and 79 per cent, respectively). The isolates from the poultry were characterized by multiple resistance. The isolates from the long-living persons were most frequently resistant to one of two antibiotics. All the tested Lactobacillus strains isolated from the long-living persons were sensitive to tetracyclines. The species composition of the isolates was different. The antibiotic-resistant strains were detected in all the species involved in the study. By hybridization of Lactobacillus colonies with the probes containing various genes of the resistance it was shown that in 14 per cent of the antibiotic-resistant strains belonging to Lactobacillus the antibiotic resistance was controlled by the genes homologous to resistance genes widely distributed in gramnegative organisms. This indicated a possible wide exchange and heterologous expression of the antibiotic resistance determinants between microorganisms of various taxonomic groups.

[Mobilization transfer of the pUB110 plasmid between gram-positive bacteria]

The three factor crosses between the donor strain Bacillus subtilis 168 harbouring the plasmid pUB102-4, Bacillus thuringiensis strain carrying the mobilizing plasmid pAM beta 1 and recipient strain Lactobacillus fermenti were conducted in order to elaborate the optimal conditions of the plasmid pUB102-4 mobilization for transfer into gram-positive microorganisms and to elucidate the possible expression of endogluconase genes in a lactobacillus strain. The Lactobacillus fermenti transconjugants carrying the pUB102-4 plasmid were obtained in the three factor reciprocal crosses with the streptococcus recipient strain and Bacillus subtilis recipients. The presence of the plasmids in transconjugants was confirmed by colony hybridization with the [32P]-labelled plasmid DNA and KMC-ase activity in transconjugant cells. The proposed system of crosses using the high copy number plasmid derivatives of pUB110 mobilized with high frequency by the pAM beta 1 plasmid demonstrates the possibility to increase the circle of gram-positive host bacteria avoiding time and labour consuming operations.

[Plasmid pBS195 with a wide range of hosts, isolated from lactobacilli]

The nonconjugative 4.4 kb plasmid pBS195 has been found in Lactobacillus sp. 195 strain resistant to kanamycin and streptomycin. The plasmid pBS195 determining the resistance to kanamycin has a broad host range. It is inherited by the Gram-positive microorganisms (Bacillus subtilis) as well as by Escherichia coli cells, has the cleavage sites for the restriction endonucleases BamHI, EcoRI, HindIII, PstI, KpnI. The restriction map of the plasmid for these enzymes is constructed. The broad host range, efficiently expressed marker, the presence of the unique restriction sites, small size make the plasmid pBS195 promising for the genetic engineering research.

[Kinetic characteristics and enantioselective action of penicillinase in the hydrolysis reaction of N-phenylacetyl derivatives of 1-aminoethylphosphonic acid and its esters]

Penicillin acylase from E. coli (EC 3.5.1.11) was found to hydrolyze N-phenylacetylated 1-aminoethylphosphonic acid and its esters. The enzyme preferentially converts the R-form of the substrates: the ratios of the bimolecular rate constants of penicillin acylasecatalyzed hydrolysis of R- and S-forms of 1-(N-phenylacetamino)-ethylphosphonic acid and its dimethyl- and diisopropyl-esters are 58000, 2300, 1800; these derivatives were shown to have the greatest values of the catalytic constants for enzymatic hydrolysis of all known substrates for penicillin acylase: 237, 148 and 134 s-1; the corresponding Km values are 3.7 10(-5), 6.8 10(-4) and 6.2 10(-4) M at pH 7.0. The kinetics of enzymatic hydrolysis of 1-(N-phenylacetamino)-ethylphosphonic acid was investigated up to high degrees of conversion. The inhibition of penicillin acylase by high concentrations of the R-form of the substrate (with substrate inhibition constant of 0.07 M) and competitive inhibition by the reaction product, phenylacetic acid (Ki = 3.5 10(-5) M), was observed.

[Antibiotic resistance in clinical strains of Pseudomonas aeruginosa isolated from 1979-1984]

The levels and spectra of drug resistance were determined in 530 strains of P. aeruginosa isolated in hospitals of three cities of the USSR within 1979-1984. Their conjugative R plasmids were searched for and distribution of various type resistance determinants in the composition of these plasmids was investigated. The results were compared with the findings of analogous studies on clinical strains of P. aeruginosa isolated within 1976-1979. It was shown that there were a rise in the relative number of the strains resistant to kanamycin and a decrease in the occurrence of the P. aeruginosa strains resistant to streptomycin, tetracycline and sulfanilamides. The frequency of the kanamycin, carbenicillin and gentamicin resistance genes in the composition of the detected conjugative R plasmids increased. Hybridization of 32P-labeled probes containing various type antibiotic resistance determinants with strains of P. aeruginosa ML (PAO) containing conjugative R plasmids was indicative of wide spread of genes determining APH(3')II and APH(3") and determinants of classes A and C in the composition of the studied plasmids.

[Genetic determinants of resistance to antibiotics in Pseudomonas bacteria]

Seven hundred and eighty nine drug resistant strains of Pseudomonas isolated in hospitals, from antibiotic production sewage and mine soils were studied in experiments on colony hybridization with the use of 32P-labeled plasmid DNA fragments containing various antibiotic resistance genetic determinants. The genes controlling production of aminoglycoside-3'-phosphotransferase, aminoglycoside-3'-adenilyl transferase, type I dihydropteroate synthetase (DHPS I) and DHPS II were detected in the strains of all the ecological niches. More than 90 per cent of the clinical strains hybridized with the samples containing these genes, though in the soil strains the main mechanisms of streptomycin and sulfanilamides resistance were probably controlled by the other nonhomologous genetic determinants studied. The gene controlling production of aminoglycoside-3'-phosphotransferase II was detected in the strains isolated both in the hospitals (49 per cent) and from the sewage (45 per cent), while the gene of aminoglycoside-3'-phosphotransferase I was detected only in the population of the clinical strains (52 per cent). The majority of the tetracycline resistant strains isolated in the hospitals and from the sewage hybridized with the samples containing the classes A and C tetracycline resistance genetic determinants. In the soil strains the genetic determinants of the main tetracycline resistance mechanism(s) were not homologous to those of classes A, B and C. Resistance of the strains to trimetoprine was as a rule determined by the genes of type II dihydrofolate reductase.

[Tetracycline resistance controlled by plasmids of Pseudomonas aeruginosa with a wide spectrum of bacterial hosts]

PBS222 and pBS223 plasmids with a wide spectrum of bacterial hosts detected in strains of P. aeruginosa control resistance of the cells of P. aeruginosa ML4262 (PAO) and E. coli C600 to 300 and 200 micrograms/ml of oxytetracycline respectively increasing 15 and 20 times their resistance to the antibiotics. The constant of the antibiotic elimination from the cells of P. aeruginosa ML4262 containing pBS223 plasmid is 3.5 times higher than the entry constant, while the constants of the antibiotic entry and elimination in the cells containing pBS222 plasmid are almost the same. Accumulation of tetracycline by the cells containing pBS223 plasmid decreases 2.8 times and that by the cells containing pBS222 plasmid decreases 1.7 times. The determinants of tetracycline resistance in pBS222 and pBS223 plasmids may be referred to the class TetC.

[Expression of the resistance genes of plasmid RP4 in Escherichia coli cells grown by continuous cultivation]

The resistance to tetracycline decreased in Escherichia coli C600 cells containing plasmid RP4 and grown under the conditions of continuous cultivation. The population of cells containing plasmid RP4 is heterogeneous in the trait of tetracycline resistance, and most cells cannot grow in a selective medium with tetracycline at a concentration of 20 micrograms/ml. The decreased resistance to tetracycline was most pronounced for a glucose-limited chemostat culture and also in the presence of two plasmids, RP4 and pBS94 , in the cells. No decrease was found in the resistance to other drugs determined by plasmid genes.

[Determination of lysine amidase and alpha-aminocaprolactam hydrolase activities in cell-free extracts of Cryptococcus sp]

he methods for detecting two activities, i. e. lysine amidase and alpha-aminocaprolactam hydrolase ones, in crude extracts of Cryptococcus sp. are described. The method for registering lysine amidase activity is based on the ability of Cu(II) complex to absorb at 230 nm. The products of lysine and alpha-aminocaprolactam interactions with o-phthalaldehyde in the presence of mercaptoethanol possess different molar absorption at 340 nm. This fact was used for detecting alpha-aminocaprolactam hydrolase activity. The main merit of the methods is the possibility to register the data on the course of the reaction without preliminary chromatographic separation of the reaction products and reactants. The methods proposed do not require expensive enzymes, such as lysine decarboxylase and lysine-alpha-ketoglutarate-epsilon-aminotransferase, which are used for the quantitative estimation of lysine.

[R-plasmids of bacteria of the genus Pseudomonas isolated from industrial sewage]

A total of 132 Pseudomonas strains isolated from untreated sewage of antibiotic plants were tested. A significant number of the strains were resistant to streptomycin (77 per cent), carbenicillin (75 per cent), kanamycin (37.5 per cent) and tetracycline (23 per cent). Eighteen conjugative and 3 nonconjugative resistance plasmids were detected in 19 strains. The genes determining the resistance to streptomycin, kanamycin and tetracycline were most frequent. The frequency of the plasmid transfer between the strains of Ps. aeruginosa (PAO) varied within 10(-3)--10(-7) per donor cell. Six plasmids belonged to group Inc P-1. Four plasmids belonged to group Inc P-2, 3 plasmids to groups Inc P-3 and Inc P-5 and 1 plasmid to group Inc P-7.

[Age variations in ethylmorphine demethylase and benzopyrene hydroxylase activities in rat liver microsomes]

The ethylmorphine demethylase activity of the rat liver microsomes was higher in three-month animals (as compared to one-month), remained at a high level in the 12-month and decreased in old rats. The benzopyrene hydrolase activity increased in three-month animals, decreased in 12-month rats and remained the same with subsequent ageing of the organism. Asynchronicity of variations in the oxidation rate of different xenobiotics with ageing is considered as a result of changes in substrate specificity of the monooxygenase system due to metabolic peculiarities which reflect the age development of the organism and extinction of the reproduction function.