Phylogenetic shadowing of a histamine-gated chloride channel involved in insect vision

A recently identified gene, hclA (synonym: ort), codes for an ionotrophic histamine receptor subunit in Drosophila melanogaster, and known hclA mutations lead to defects in the visual system, neurologic disorders and changed responsiveness to neurotoxins. To investigate whether this novel class of receptors is common across the Insecta, we analysed the genomes of 15 other insect species (Diptera, Hymenoptera, Coleoptera, Lepidoptera) and revealed orthologs of hclA in all of them. The predicted receptor domain of HCLA is extensively conserved (86-100% of identity) among the 16 proteins. Minor changes in the amino acid sequence that includes the putative transmembrane domains (TMs) 1-3 were found in non-drosophilid species only. Substantial amino acid variability was observed in the signal polypeptides, the intracellular loop domains and in TM4, in good accordance with known data on sequence variations in ligand-gated ion channels. Pairwise comparisons revealed three consensus sequences for N-glycosylation, conserved in HCLAs of all species studied, as well as a drosophilid-specific putative phosphorylation site. Real-time PCR analysis demonstrated that hclA-mRNA is abundant in heads of adult Drosophila. However, species- and sex-specific variations of the hclA expression levels were also observed.     

A synthetic derivative of plant allylpolyalkoxybenzenes induces selective loss of motile cilia in sea urchin embryos.

Polyalkoxybenzenes are plant components displaying a wide range of biological activities. In these studies, we synthesized apiol and dillapiol isoxazoline analogues of combretastatins and evaluated their effect on sea urchin embryos. We have shown that p-methoxyphenyl isoxazoline caused sea urchin embryo immobilization due to the selective excision of motile cilia, whereas long immotile sensory cilia of apical tuft remained intact. This effect was completely reversed by washing the embryos. The compound did not alter cell division, blastulae hatching, and larval morphogenesis. In our hands, the molecule would serve as a convenient tool for in vivo studying morphogenetic processes in the sea urchin embryo. We anticipate that both the assay and the described derivative could be used for studies in ciliary function in embryogenesis.     

Study of the mutagenic and antimutagenic activity of the human and animal blood]

Mutagenic and antimutagenic properties of humans, bull, rabbit, chick, rat, and mouse were studied using seeds of Crepis capillaries (the chromosome aberration test). Antimutagenic activity was found in pre-processing, combined, and post-processing conditions of the seeds with a blood relative to the mutation inductors. Whole human and animal blood was found to be capable of inducing chromosome aberrations far exceeding the level of spontaneous mutations. Dilution of the blood did not eliminate its antimutagenic activity.     

Particles of liquid-crystalline dispersions formed by (nucleic acid-rare earth element) complexes as a potential platform for neutron capture therapy

Microscopic size particles of the cholesteric double-stranded DNA (RNA) liquid-crystalline dispersions, containing the ions of the rare earth elements in their content, have been obtained for the first time. The properties of these particles differ from those of classical DNA cholesterics noticeably. The local concentration of the rare earth elements in a particle reaches 200 mg/ml. The particles of the liquid-crystalline dispersion of the (DNA-gadolinium) complex maintain the properties for a long time. The combination of the microscopic size of particles, high concentration of gadolinium in particles and their stability opens a way to practical application of this new biomaterial.     

Dynamics of viral hepatitis A morbidity in Minsk

The results of the analysis of hepatitis A morbidity during the period of 1996 - 2001, are presented. The cyclic character of this morbidity in its dynamics over the period of several years was noted with the maximum morbidity level reached in 2000. The monthly dynamics of hepatitis A morbidity reflected its seasonal character with the maximum increase in autumn and winter. The virological control of drinking water revealed its contamination in spring and summer, with no subsequent rise in morbidity. The control of sewage reflected the emergence of the virus in the city collector in accordance with the increased morbidity.     

Immunovac-VP-4, immunomodulator decreases immunosuppression and enhances the cytotoxic activity induced by the cytostatic Cisplatin

The influence of the vaccine Immunovac-VP-4, prepared from the antigens of opportunistic microorganisms, on the proliferative and cytotoxic activity on peripheral blood mononuclears (PBMN) from healthy donors in vitro and on spleen cells of CBA mice in vivo during their incubation with Cisplatin was studied. VP-4 produced a dose-dependent, stimulating effect on the proliferative potential of PBMN and, when used in the highest of all tested doses (20 microg/ml), increased the Cisplatin-suppressed proliferative activity of PBMN in 9.4-fold. VP-4 increased the cytotoxic activity of PBMN on tumor line cells K-562 (38,4 to 60.1%) and increased the cytotoxic effect of Cisplatin (68.18 to 87.56%). A single injection of VP-4 to mice stimulated the proliferative activity of spleen cells, studied ex vivo, units and partially restored their cytostatic-suppressed activity. The cytotoxic action of the spleen cells of immunized mice on tumor line cells YAC-1 was twice as great as that of spleen cells taken from intact animals and potentiated the cytotoxic action of Cisplatin. The mechanism of increasing the proliferative activity and cytotoxic effect of monomuclears under the influence of vaccine VP-4 is seemingly linked with the synthesis of cytokines, influencing the lymphokine-activated cytotoxicity of lymphocytes.     

Generation of dendrite cells and the use of immunomodulators of bacterial origin as cell differentiation inducers

The generation of ripe dendrite cells (DC) of marrow origin was obtained with the use of the vaccine Immunovac-BN-4, an immunomodulator of microbial origin, as well as Klebsiella pneumoniae LPS and TNF-alpha, as ripening inducers. These inducers equally led to the ripening of DC. The generation of ripe DC was characterized by morphological, phenotypical and functional changes. The immunophenotype of cells altered from CD34+, CD38-, CD40-, CD80-, CD86-, MHC I-, MHC II-, F4/80- to CD34-, CD38+, CD40+, CD80+, MHC I+, MHC II+, F4/ 80(low). In parallel with the ripening of DC their phagocytic activity decreased. In culture medium with ripe DC the levels of such cytokines as IL-1b, IL-6, IL-12, IFN-gamma, TNF-alpha significantly increased and the production of IL-4 decreased. The content of IL-2 and IL-10 remained unchanged.     

Human milk lactoferrin hydrolyzes nucleoside-5'-triphosphates

Lactoferrin (LF) is a main iron-transfering glycoprotein of human barrier body fluids, blood and milk. LF, a protein of the acute phase, is responsible for nonspecific cells defense against microbial and viral infection and cancer diseases. LF is an important component of the passive immunity of newborns system. LF, an extremely polyfunctional protein, is the object of intensive investigations. In this work electrophoretically homogeneous LF from human milk was prepared. Affinity chromatography of LF on Blue Sepharose separated the protein into several distinct isoforms with different affinities to this resin. Two of this isoforms possess nucleoside-5'-triphosphate-hydrolyzing activity. Using several methods including in-gel ATPase activity assays, we show that ATP (and others NTP) hydrolysis is an intrinsic property of LF, and that LF is the major ATPase of human milk. It was shown that ATP-hydrolyzing site is located in C-lobe of LF.     

Genoprotective human blood activity and its mechanisms

Anticlastogenic properties of plasma and proteins (albumin and gamma-globulin) of the human blood were studied using seeds of Crepis capillaris (chromosome aberration assay). Antimutagen p-amino-benzoic acid was used as a comparative reagent. Anticlastogenic activity dependent of processing conditions of the biosubstrate used; for the pre-processing and combined processing anticlastogenic effect was higher than for post-processing, the processing properties of the blood being higher than those of the blood proteins. Anticlastogenic potential of biosubstrates did not depend on mutation inductor. Complex-formimg properties of plasma and blood albumen have been revealed using spectrop-hotometry through the substantial spectral displacement--relative to the expected spectrum--for the mixture of biosubstrata and mutagens. Using chemoluminescence, all plasma, albumin and gamma-globulin concentrations have been shown to enhance generation of hydroxyl radical of the Fenton reagent, especially for albumin in 1.0 g/l concentration. The general trend for all experiments was that the said substances diminished the stimulating effect as their concentrations grew. Peroxidation of yolk lipoproteids showed that only high concentrations of blood's plasma and albumen have antioxidizing properties. gamma-Globulin did not reveal any ability to inhibit lipid peroxidation of yolk lipoproteids. Complex-forming mechanisms of blood's albumen and antioxidizing property of human plasma and proteins have been proved to form the blood's anticlastogenic potential.     

Control of beta-catenin phosphorylation/degradation by a dual-kinase mechanism

Wnt regulation of beta-catenin degradation is essential for development and carcinogenesis. beta-catenin degradation is initiated upon amino-terminal serine/threonine phosphorylation, which is believed to be performed by glycogen synthase kinase-3 (GSK-3) in complex with tumor suppressor proteins Axin and adnomatous polyposis coli (APC). Here we describe another Axin-associated kinase, whose phosphorylation of beta-catenin precedes and is required for subsequent GSK-3 phosphorylation of beta-catenin. This "priming" kinase is casein kinase Ialpha (CKIalpha). Depletion of CKIalpha inhibits beta-catenin phosphorylation and degradation and causes abnormal embryogenesis associated with excessive Wnt/beta-catenin signaling. Our study uncovers distinct roles and steps of beta-catenin phosphorylation, identifies CKIalpha as a component in Wnt/beta-catenin signaling, and has implications to pathogenesis/therapeutics of human cancers and diabetes.