Initial data on biological activity of taiga-steppe soils in the lower reaches of the Kolyma River.

Microbiological and enzyme activities of extrazonal taiga-steppe soils in the lower reaches of the Kolyma River have been studied for the first time. Contrary to north-taiga cryometamorphic soils, predominating in the area, microbial cenoses under herb-sedge petrophytic and grass-sagebrush-herb thermophytic steppes are characterized by features typical for arid soils. The saturation of the soil profile with microorganisms is greater, and the development of actinomycetes is more intensive. The enzyme complex is characterized by high activity of dehydrogenases.

[The Effect of Transcription on Enhancer Activity in Drosophila melanogaster].

In higher eukaryotes, the level of gene transcription is under the control of DNA regulatory elements, such as promoter, from which transcription is initiated with the participation of RNA polymerase II and general transcription factors, as well as the enhancer, which increase the rate of transcription with the involvement of activator proteins and cofactors. It was demonstrated that enhancers are often located in the transcribed regions of the genome. We showed earlier that transcription negatively affected the activity of enhancers in Drosophila in model transgenic systems. In this study, we tested the effect of the distance between the leading promoter, enhancer, and target promoter on the inhibitory effect of transcriptions of different strengths. It was demonstrated that the negative effect of transcription remained, but weakened with increased distance between the leading promoter and enhancer and with decreased distance between the enhancer and target promoter. Thus, transcription can modulate the activity of enhancers by controlling its maximum level.

[Distant interactions between enhancers and promoters in Drosophila melanogaster are mediated by transgene-flanking Su(Hw) insulators].

Insulators are DNA elements modulating gene activation by enhancers. Interaction between insulators can result in either isolation, or activation of promoter by the enhancer. In the present study, it is demonstrated that in transgenic lines, the yellow enhancers are unable to activate promoter of the tagged gene through the mini-white gene. The mini-white promoter, which functions as an insulator, can block the enhancer activity. In case that the genes and regulatory elements in the construct are flanked by Su(Hw) insulators from retroposon MDG4, interaction between enhancers and the yellow promoter is restored. The data obtained are congruent with the model suggesting that promoters can function as insulators, and that interaction between the insulators facilitates the interaction between enhancers and promoters within transcriptional domain.

Sulfated cellulose derivatives inhibit activities of thrombin and activated factor X.

Sulfated derivatives based on powdered cellulose were obtained, including those containing additional (carboxymethyl, ethyl amide or phosphate) groups, and their activity against blood clotting factors (thrombin and Xa) was studied. Maximum antithrombin activity of the test compounds, measured using a coagulation test, was 144±11 U/mg.

[Neurochemical study of effects of the new anxiolytic drugs afobazol and ladasten on the synthesis and metabolism of monoamines and their metabolites in the brain structures of Wistar rat on the model of monoamine synthesis blockade induced by aromatic amino acid decarboxylase inhibitor NSD-1015].

Results of a neurochemical study of the effects of the new anxiolytic drugs afobazole and ladasten on the synthesis and metabolism of monoamines and their metabolites determined by HPLC on the model of monoamine synthesis blockade induced by NSD-1015 (aromatic L-amino acid decarboxylase) in the brain structures of Wistar rats are reported. A decrease in the levels of DOPAC in hypothalamus and HVA in striatum after afobazole injection may be evidence of an inhibitory action of this drug on the activity of monoamine oxidase (MAO-A), which is the main enzyme involved in dopamine biodegradation. Afobazole was also found to increase the content of serotonin (5-HT) as well as its precursor (5-OTP) and its main metabolite (5-HIAA) in hypothalamus by up to 50, 60 and 50%, respectively, which confirms a hypothesis that this anxiolytic drug can modulate the activity of tryptophan hydroxylase (5-OTP synthesis enzyme). In contrast to afobazole, ladasten demonstrated the ability to increase the level of L-DOPA (a dopamine precursor) in virtually all functional structures of the brain (except for hippocamp), which may support the hypothesis suggestion concerning a predominant action of this drug on the activity of tyrosine hydroxylase. Ladasten exhibited selectivity with respect to the dopaminergic system and affected only parameters of the dopamine metabolism, in particular, by increasing the HVA content in nucleus accumbens and decreasing it in the hypothalamus. The drug also affected the dopamine turnover parameters, producing an increase in both HVA/dopamine ratio in nucleus accumbens and DOPAC/dopamine ratio in hippocamp.

[Anticoagulant activity of arabinogalactane sulfate and cedar bark extract studied in vitro].

We have studied in vitro the ability of the Siberian cedar crust (SCC) extract (Pinus sibirica Du Tour) and arabinogalactan sulphate (AGS) extracted from wood of Siberiam pine-tree (Larix sibirica Ledeb.) to increase the human blood plasma coagulation time and also to inhibit the amydolytic activity of thrombin (aIIa) and the coagulation factor Xa (aXa). A method has been developed by means of which SCC increases the aXa activity by a factor of 3.7 and the aIIà activity by a factor of 2.5. The AGS preparation increased the blood plasma coagulation time in the test for activated partial thromboplastin time. An effective concentration, at which the time of plasma coagulation was increased by a factor of 2 (in comparison to the control) was 2.94 +/- 0.33 mg/ml. AGS did not exhibit the ability to inhibit the Xa activity.

[Autoimmune nature of spermatogenesis disorders in varicocele models in rats]. / Ob autoimmunnoi prirode narusheniia spermatogeneza pri modelirovanii varikotsele na krysakh.

Partial decrease of venous drainage from the left testis in male rats induced development of destructive changes in the seminiferous epithelium at the site of operation and in the contralateral organ. Spermatogenesis disturbances in the rat testes (focal desquamation of seminiferous epithelium, disorganization and degeneration of germ cells, devastation of seminiferous tubules) resembles the lesion in men with varicocele. These data permit to consider the results of present experiment as varicocele modelling. Disturbance of permeability and of the fine blood-testis barrier structure in both testes was observed in experimental rats; the picture of morphological changes was similar to that of autoimmune orchitis; lymphocytes sensitized to spermatozoa antigens were revealed in the lymphoid organs of experimental rats. The results obtained permit to suggest the involvement of immunological mechanisms in the development of pathological changes in the testes affected with varicocele.

[Human, guinea pig and rat lympocyte rosette formation with spermatozoids]. / Obrazovaine limfotsitami cheloveka, morskikh svinok i krys rozetok so spermatozoidami

In the thymus, spleen and bone marrow of adult guinea pigs, 14--30-week human fetuses, and the peripheral blood of sterile men there were found cells capable of forming the rosettes with homo- or heterologous spermatozoa (RFC). Development of autoimmune orchitis after the trauma of the rat testis or after the guinea pig immunization with the testicular homogenate mixed with complete Freund's adjuvant caused the appearance of RFC with spermatozoa in the thymus and the spleen of rats, and an increase of their number in the lymphoid organs of guinea pigs. Such treatment did not influence the quantity of sheep-cell rosettes in the lymphoid organs of rats and guinea pigs. A possibility of using the detected capacity of animal and human lymphocytes to form spontaneous and immune rosettes with the spermatozoa to test the degree of lympocyte differentiation and their sensitisation to the spermatozoa antigens after the spermatogenesis distrubances of the autoimmune nature is discussed.

[Induction of experimental autoimmune orchitis in guinea pigs after ligation of the seminiferous ducts]. / Induktsiia éksperimental'nogo autoimmunnogo orkhita u morskikh svinok posle pereviazki semiavynosiashchikh protokov

PIP: In 18 immature guinea pigs both sides of the vasa efferentia were ligated; 18 control animals were not altered. The ligation did not prevent the formation in mature animals of active spermatogenesis in the majority of seminiferous tubules, but did cause a reduction in the number of layers of seminiferous epithelium in some, and atrophy of the epididymis due to the absence of germ cells. Immunization, in the adult stage, with homogenate of homologous testis mixed with complete Freund adjuvant created changes in the permeability of the blood-testis barrier in relation to endogenous globulins and rivanol and the development of autoimmune orchitis of the same intensity and terms as in the control animals. In contrast to the control group, destructive changes in the testis did not follow with inflammatory processes in the epididymis.^ieng