Efficiency of Neopsylla abagaitui fleas as plague vectors in Transbaikalia

Experiments have shown that the block of proventriculus develops in 1.1 to 1.5% of individuals of the flea Neopsylla abagaitui infected with plague microbe. These insects transmit the agent during bloodsucking to different plague carriers (Citellus dauricus, C. undulatus, Meriones unguiculatus, Microtus gregalis). The plague microbe is preserved in fleas for 65 days (the observation period).     

RNA and DNA synthesis catalyzed by a DNA-polymerase alpha complex with primase from silkworm cells on single-stranded DNA]

Depending on the ionic environment the replicative complex of silkworm Bombyx mori, containing DNA polymerase alpha and primase, catalyzes on single-stranded DNA of phage M13 a NTP-dependent synthesis or elongation of preformed primers. In the presence of NTPs and dNTPs at conditions optimal for the NTP-dependent synthesis the replicative complex synthesizes on M13 DNA oligoribonucleotides of 9-11 residues, which serve as primers for polymerization of DNA. The length of RNA-primers synthesized by primase of the complex depends on concentration of dNTP but does not depend on activity of DNA polymerase alpha. During elongation of exogenic primers annealed to M13 DNA the complex is processive synthesizing DNA fragments of dozens residues without dissociation from the template. Double-stranded structures in DNA such as "hairpins" appear to be barriers for driving of the complex along the template and cause pauses in elongation. DNA-binding proteins the SSB of Escherichia coli or the p32 of phage T4 destabilize double-stranded regions in DNA and eliminate elongation pauses corresponding to these regions. The replicative complex is able to fill in single-stranded gaps in DNA completely and to perform slowly the synthesis with displacement of one of parent strands in duplexes via repeated cycles of binding to the primer-template, limited elongation and dissociation.     

Myelotoxicity of epirubicin]

Epirubicin (pharmorubicin, India), an antitumor antibiotic of the anthracycline group, was studied in regard to its effect on peripheral blood, bone marrow and lymphoid organs (the thymus and spleen) of CBA mice after its intraperitoneal administration in a single dose equal to the MIC (7.8 mg/kg) and in a course dose (1/5 of the MIC 5 times a day). The cytogenetic impairments induced by the cytostatic were estimated on metaphase plates with the bone marrow specimens and by counting the peripheral blood erythrocytes with micronuclei (the micronuclear test). It was shown that epirubicin induced cytogenetic disturbances in the hemopoietic cells within the first 72 hours. The antibiotic had a marked reversible effect on the erythroid population and lymphoid tissues and a moderate toxic action on the granulocyte population. The antibiotic did not affect thrombocytopoiesis. The single administrations had a more pronounced and prolonged myelotoxic and lymphotropic effect.     

Characterization of the protein apparently responsible for the elevated tyrosine protein kinase activity in LSTRA cells.

The LSTRA murine thymoma cell line contains an elevated level of tyrosine protein kinase activity. When a microsomal preparation from these cells is incubated in vitro with ATP, the principal tyrosine protein kinase substrate is a 56,000-dalton protein, p56. We have found that an activity phosphorylating p56 on tyrosine can also be detected at low levels in microsomes from most, but not all, T lymphoma cell lines and from normal thymic tissue. Only 1 of 30 other lymphoma cell lines was found to contain an elevated level of such a tyrosine protein kinase. An activity that phosphorylated p56 in vitro was not detectable in the cells of other hematopoietic lineages. Anti-peptide antibodies reactive with the site of in vitro tyrosine phosphorylation of p56 allowed us to determine that the apparent abundance of the p56 polypeptide parallels closely the level of the tyrosine protein kinase activity in the cell lines examined. This suggests that p56 is the protein kinase responsible for the elevated tyrosine protein kinase activity in LSTRA cells and that the phosphorylation of p56 observed in vitro results from autophosphorylation. Two-dimensional tryptic peptide mapping revealed that p56 is distinct from the proteins encoded by the cellular genes which are the progenitors of retroviral tyrosine protein kinases, src, yes, fgr, abl, fes, and ros. Additionally, none of these proto-oncogenes was found to be transcribed at elevated levels in LSTRA or Thy19 cells. Like the catalytic subunit of the cyclic AMP-dependent protein kinase, the cellular and viral forms of p60src, and the protein phosphatase calcineurin B, p56 contains covalently bound fatty acid.     

Construction and expression of a recombinant DNA gene encoding a polyomavirus middle-size tumor antigen with the carboxyl terminus of the vesicular stomatitis virus glycoprotein G.

We constructed a molecular clone encoding the N-terminal 379 amino acids of the polyomavirus middle-size tumor antigen, followed by the C-terminal 60 amino acids of the vesicular stomatitis virus glycoprotein G. This hybrid gene contained the coding region for the C-terminal hydrophobic membrane-spanning domain of the G protein in place of the C-terminal hydrophobic domain of the middle-size tumor antigen. The hybrid gene was expressed in COS-1 cells under the control of the simian virus 40 late promoter. The hybrid protein was located in cell membranes and was associated with a tyrosine-specific protein kinase activity, as was the middle-size tumor antigen. Plasmids encoding the hybrid protein failed to transform mouse NIH 3T3 or rat F2408 cells.     

Molecular complexes of amino acids with porphyrins as possible precursors of pigment-protein systems

The present communication gives experimental results of the studies of catalytic and photochemical properties of peptide-like compounds containing metalloporphyrins (hemoproteinoids and molecular complexes obtained through adsorption of porphyrins and amino acids on volcanic ash). The data suggest that molecular complexes of amino acids with porphyrins could have evolved in the course of chemical evolution and were intermediated between abiogenically synthesized molecules of amino acids and porphyrins and pigment-protein systems of living organisms.     

Dispersibility of Nanocrystalline Cellulose in Organic Solvents

Russian Journal of Bioorganic Chemistry - Aqueous suspensions of nanocrystalline cellulose (NCC) were obtained by sulfuric acid hydrolysis using the standard procedure. Suspensions, films, and...     

Testing of the method for water microleakage detection from OH hydroxyl spectral lines at the L-2M stellarator

Results are presented from L-2M stellarator experiments on testing a possible method for detection of water microleakages in the cooling system of the first wall and vacuum chamber of ITER. The method consists in the spectroscopic detection of spectral lines of the OH hydroxyl, which forms via the dissociation of water molecules in plasma. Emission in the spectral band of 305–310 nm can be detected even at water leakage rates less than 10^?4 Pa m³/s. Chemical reactions between water and boron compounds on the vacuum chamber wall delay the detection of leakages up to ～2000 s. A similar phenomenon can be expected when a leakage will occur in ITER, where the materials suggested for the first wall (Be, Li) can also chemically react with water.     

Influence of Catecholamines on Migration and Differentiation of GnRH Neurons in Rats

The GnRH producing neurons are the key link of neuroendocrine regulation of the adult reproductive system. Synthesis and secretion of GnRH are, in turn, under the afferent catecholaminergic control. Taking into account that catecholamines exert morphogenetic effects on target cells during ontogenesis, this study was aimed at investigation of the effects of catecholamines on development of GnRH neurons in rats during ontogenesis. We carried out comparative quantitative and semiquantitative analyses of differentiation and migration of GnRH neurons in fetuses of both sexes under the conditions of normal metabolism of catecholamines (administration of saline) or their pharmacologically induced deficiency (administration of -methyl-para-tyrosine). The inhibition of catecholamine synthesis from day 11 of embryogenesis led to an increasing number of GnRH neurons in rostral regions of the trajectory of their migration over the brain: in the area of olfactory tubercles on day 17 and in the area of olfactory bulb on days 18 and 21. In addition, the optical density of GnRH neurons located in the rostral regions of migration was higher in the fetuses after administration of -methyl-para-tyrosine during embryogenesis, as compared to the control. It has been concluded that catecholamines stimulate the migration of GnRH neurons and affect their differentiation.