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1.
Argiopine,argiopinines, and pseudoargiopinines as glutamate receptor blockers in hippocampal neurons
N. I. Kiskin O. A. Kryshtal' A. Ya. Tsyndrenko T. M. Volkova E. V. Grishin 《Neurophysiology》1989,21(6):525-532
A homologous set of low-molecular weight compounds selectively blocking ionic currents were purified from venom from the spiderArgiope lobata with a selective blocking action on ionic currents activated by applying glutamate and its agonist kainic acid (KA) to the membrane of neurons isolated from the rat hippocampus. Three groups of these compounds — argiopine, argiopinines, and pseudoargiopinines, produced voltage-dependent glutamate- and KA-activated ionic currents at concentrations of 10–6-10–4 M, interacting primarily with agonist-activated ionic channels without affecting Kd values of the agonist. The blocking action could be partially reversed by argiopine application but only slightly when argiopinines and pseudoargiopinines were used. Kinetics of toxin effects on Ka-activated ionic currents showed at least two exponential components with different time constants. Simple and reversed rate constants of interaction between toxins and ionic channels were estimated from the plot of the kinetics of ionic current blockade and recovery against toxin concentration. Argiopine, argiopinines, and pseudoargiopinines lend themselves to further research into glutamate receptors of the mammalian CNS employing electrophysiological and biochemical techniques.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev, M. M. Shemyakin Institute of Bioorganic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 21, No. 6, pp. 748–756, November–December, 1989. 相似文献
2.
Z A Khuchua R Ventura-Clapier A V Kuznetsov M N Grishin V A Saks 《Biochemical and biophysical research communications》1989,165(2):748-757
Immunochemical and biochemical methods were used to assess quantitatively the changes in the heart creatine kinase system in the myopathic Syrian hamsters, line CHF I46. Cardiomyopathy in I75-200 day old animals was characterized by decreased content of mitochondria and lower total creatine kinase activity. In isolated mitochondria only the creatine kinase activity was decreased while cytochromes aa3 content and respiration rate were unchanged. The share of mitochondrial creatine kinase in the total tissue enzyme activity was decreased from 33% to I8% and that of BB form was elevated from 5% in control to 20%, at unchanged relative level of MM. Immunoassay showed decreased amount of the mitochondrial creatine kinase in the tissue and its decreased ratio to cytochromes aa3. The results show altered expression of creatine kinase isoenzymes in cardiomyopathy. 相似文献
3.
Thiobacillus ferrooxidans was used in fixed-film bioreactors to oxidize ferrous sulfate to ferric sulfate. Glass beads, ion-exchange resin, and activated-carbon particles were tested as support matrix materials. Activated carbon was tested in both a packed-bed bioreactor and a fluidized-bed bioreactor; the other matrix materials were used in packed-bed reactors. Activated carbon displayed the most suitable characteristics for use as a support matrix of T. ferrooxidans fixed-film formation. The reactors were operated within a pH range of 1.35 to 1.5, which effectively reduced the amount of ferric iron precipitation and eliminated diffusion control of mass transfer due to precipitation. The activated-carbon packed-bed reactor displayed the most favorable biomass holdup and kinetic performance related to ferrous sulfate oxidation. The fastest kinetic performance achieved with the activated-carbon packed-bed bioreactor was 78 g of Fe oxidized per liter per h (1,400 mmol of Fe oxidized per liter per h) at a true dilution rate of 40/h, which represents a hydraulic retention time of 1.5 min. 相似文献
4.
A G Petrenko V A Kovalenko O G Shamotienko I N Surkova T A Tarasyuk Ushkaryov YuA E V Grishin 《The EMBO journal》1990,9(6):2023-2027
The receptor protein of alpha-latrotoxin (alpha LTx, a neurotoxin with 'pure' presynaptic action isolated from black widow spider venom), was solubilized by Triton X-100 from bovine brain membranes and purified by affinity chromatography on alpha LTx-Sepharose. The purified receptor preparation contained four major polypeptides of molecular masses 200 (alpha), 160 (alpha'), 79 (beta) and 43 (gamma) kd according to SDS electrophoresis with molecular ratio alpha 1 alpha' 1 beta 2 gamma 2. The alpha- and alpha'-subunits are glycoproteins binding to wheat germ lectin and can be separated under non-denaturing conditions by anion exchange chromatography. Purified to homogeneity, both of them, though differing in the carbohydrate composition, retain the alpha LTx-binding activity and give closely related peptide maps. Anti-alpha antibodies recognize the alpha'-subunit as well. These results suggest that alpha LTx receptor is present in purified preparations in two very close forms containing the alpha- or alpha'-subunit. Beta and gamma proteins do not specifically bind alpha LTx and their physiological role is unclear. They form a complex with solubilized alpha- and alpha'-subunits independently of alpha LTx presence. The receptor proteins were purified to homogeneity by high performance gel filtration in the presence of SDS, their amino acid composition was determined. 相似文献
5.
Dmitry E. Nolde Alexander G. Sobol Kirill A. Pluzhnikov Eugene V. Grishin Alexander S. Arseniev 《Journal of biomolecular NMR》1995,5(1):1-13
Summary Two-dimensional 1H NMR techniques were used to determine the spatial structure of ectatomin, a toxin from the venom of the ant Ectatomma tuberculatum. Nearly complete proton resonance assignments for two chains of ectatomin (37 and 34 amino acid residues, respectively) were
obtained using 2D TOCSY, DQF-COSY and NOESY experiments. The cross-peak volumes in NOESY spectra were used to define the local
structure of the protein and generate accurate proton-proton distance constraints employing the MARDIGRAS program. Disulfide
bonds were located by analyzing the global fold of ectatomin, calculated with the distance geometry program DIANA. These data,
combined with data on the rate of exchange of amide protons with deuterium, were used to obtain a final set of 20 structures
by DIANA. These structures were refined by unrestrained energy minimization using the CHARMm program. The resulting rms deviations
over 20 structures (excluding the mobile N- and C-termini of each chain) are 0.75 ? for backbone heavy atoms, and 1.25 ? for
all heavy atoms. The conformations of the two chains are similar. Each chain consists of two α-helices and a hinge region
of four residues; this forms a hairpin structure which is stabilized by disulfide bridges. The hinge regions of the two chains
are connected together by a third disulfide bridge. Thus, ectatomin forms a four-α-helical bundle structure. 相似文献
6.
The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs. 相似文献
7.
Andrey M. Grishin Eunice Ajamian Linhua Zhang Isabelle Rouiller Mihnea Bostina Miroslaw Cygler 《The Journal of biological chemistry》2012,287(45):37986-37996
Microbial anaerobic and so-called hybrid pathways for degradation of aromatic compounds contain β-oxidation-like steps. These reactions convert the product of the opening of the aromatic ring to common metabolites. The hybrid phenylacetate degradation pathway is encoded in Escherichia coli by the paa operon containing genes for 10 enzymes. Previously, we have analyzed protein-protein interactions among the enzymes catalyzing the initial oxidation steps in the paa pathway (Grishin, A. M., Ajamian, E., Tao, L., Zhang, L., Menard, R., and Cygler, M. (2011) J. Biol. Chem. 286, 10735–10743). Here we report characterization of interactions between the remaining enzymes of this pathway and show another stable complex, PaaFG, an enoyl-CoA hydratase and enoyl-Coa isomerase, both belonging to the crotonase superfamily. These steps are biochemically similar to the well studied fatty acid β-oxidation, which can be catalyzed by individual monofunctional enzymes, multifunctional enzymes comprising several domains, or enzymatic complexes such as the bacterial fatty acid β-oxidation complex. We have determined the structure of the PaaFG complex and determined that although individually PaaF and PaaG are similar to enzymes from the fatty acid β-oxidation pathway, the structure of the complex is dissimilar from bacterial fatty acid β-oxidation complexes. The PaaFG complex has a four-layered structure composed of homotrimeric discs of PaaF and PaaG. The active sites of PaaF and PaaG are adapted to accept the intermediary components of the Paa pathway, different from those of the fatty acid β-oxidation. The association of PaaF and PaaG into a stable complex might serve to speed up the steps of the pathway following the conversion of phenylacetyl-CoA to a toxic and unstable epoxide-CoA by PaaABCE monooxygenase. 相似文献
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10.
AB Zarafi AM Emechebe AD Akpa O Alabi 《Archives Of Phytopathology And Plant Protection》2013,46(4):261-268
Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight. 相似文献