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1.
Subunit interactions in the first component of complement, C1 总被引:1,自引:0,他引:1
S Lakatos 《Biochemical and biophysical research communications》1987,149(2):378-384
Interactions between C1q and other subunits of C1 were analyzed by sucrose gradient ultracentrifugation. A zone of dilute, radioiodine labelled C1q was sedimented through uniform concentrations of either C1r2C1s2, C1r2, C1r2 or C1s(2). The dissociation constants were found to be 3 x 10(-9) M and 6 x 10(-9) M for C1r2C1s2 and C1r2 binding respectively. Hill coefficients of 1 indicated no cooperativity in these bindings. Positive cooperativity was found in binding of C1s to C1q. Dissociation constants of 2 x 10(-6) M and 5 x 10(-8) M were obtained form computer modelling of a two step binding mechanism. No interaction was detected between C1q and activated C1r2. The data indicate that most of the interactions between C1q and C1r2C1s2 originates from a strong binding to the C1r2 moiety of the zymogen complex. This interaction is lost upon activation of C1r2. 相似文献
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Ernő Berényi Péter Surányi Katalin Pálóczi Gyula Szegedi 《Cancer immunology, immunotherapy : CII》1986,21(2):164-166
Summary The percentage and absolute number of lymphocytes and Leu 7+ cells were significantly lower in HD even in active stages. There was no significant difference in the percentage of LGL between the three groups (control, active HD, inactive HD), however, because of differences in counts of lymphocytes the absolute number of LGL was significantly lower in HD even in the active group than that in healthy controls. The absolute count of LGL and Leu 7+ cells in patients in remission was significantly higher than that in active HD. Natural cytotoxicity against K-562 cells was also significantly lower in active patients in comparison with controls, while the percentage of cytotoxicity was slightly but not significantly higher in patients in remission than that in the active group. A positive correlation was observed between all the three examined parameters both in controls and in patients with active and inactive HD. 相似文献
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Béatrice Drouet Luis Garcia Dominique Simon-Chazottes Marie Geneviève Mattei Jean-Louis Guénet Arnold Schwartz Gyula Varadi Martine Pinçon-Raymond 《Mammalian genome》1993,4(9):499-503
Using both chromosomal in situ hybridization and molecular techniques, we report the genetic localization of the gene coding for the alpha 1 subunit of the skeletal slow Ca2+ current channel/DHP receptor gene (Cchl1a3) on human Chromosome (Chr) 1 (1q31–1q32 region) and on mouse Chr 1 region (F-G). On the basis of single-strand conformation polymorphism (SSCP-PCR) analysis in an interspecific backcross, we have determined that the Cchl1a3=mdg (muscular dysgenesis) locus is very closely linked to the myogenin (Myog) locus. 相似文献
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Mutant rat trypsin Asp189Ser was prepared and complexed with highly purified human α1-proteinase inhibitor. The complex formed was purified to homogeneity and studied by N-terminal amino acid sequence analysis and limited proteolysis with bovine trypsin. As compared to uncomplexed mutant trypsin, the mutant enzyme complexed with α1-proteinase inhibitor showed a highly increased susceptibility to enzymatic digestion. The peptide bond selectively attacked by bovine trypsin was identified as the Arg117-Val118 one of trypsin. The structural and mechanistic relevance of this observation to serine proteinase-substrate and serine proteinase-serpin reactions are discussed. 相似文献
7.
The effects of high oxygen pressure on pyruvate dehydrogenase (pyruvate: lipoate oxidoreductase (decarboxylating and acceptor-acylating), EC 1.2.4.1) activity, tissue concentration of ATP, and CO2 production from glucose were studied in rat brain cortical slices. The increase in pyruvate dehydrogenase activity and the lowering of cellular ATP, occurring during potassium-induced depolarization at 1 atm of oxygen, were reversed by increasing the oxygen pressure to 5 atm. When brain slices were incubated at 1 atm oxygen with [U-14C]glucose, a high potassium medium approximately doubled the production of 14CO2. Oxygen at 5 atm abolished this potassium-dependent increase in 14CO2 production with no significant effect on glucose oxidation in normal Krebs-Ringer phosphate medium. Adding 4 atm helium to 1 atm oxygen did not interfere with the ability of potassium ions to activate pyruvate dehydrogenase, lower ATP, or increase glucose oxidation. The results show that toxic effects of hyperbaric oxygen, not manifest in “resting” tissue, may be revealed during stress such as potassium depolarization. The site of the toxic effects of oxygen is probably the cell membrane where excess oxygen appears to interfere with the action of the sodium pump, calcium transport or other processes stimulated by increased concentrations of extracellular potassium. 相似文献
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Abandonment of the name eloxanthin is proposed. The principal carotenoids in various species of Elodea were (3R, 3′R, 6′R)-lutein (β,ε-carotene-3, 3′-diol) and β, β-carotene. The minor pigments were neoxanthin-X (5′, 6′-epoxy-6, 7-didehydro-5, 6, 5′, 6′-tetrahydro-β, β-carotene-3, 5, 3′-triol), 9′-cis-neoxanthin- X, 9- and 13-cis-violaxanthin (5, 6, 5′, 6′-diepoxy-5, 6, 5′, 6′-tetrahydro-β, β-carotene-3, 3′-diol), antheraxanthin (5, 6-epoxy-5, 6-dihydro-β, β-carotene-3, 3′-diol), neolutein A (13- or 13′-cis-lutein) and neolutein B (9- or 9′-cis-lutein). All attempts to isolate eloxanthin failed. 相似文献
10.
Tomáš Fiala Jaroslav Holuša Jiří Procházka Lukáš Čížek Marek Dzurenko Jiří Foit Juraj Galko Josef Kašák Jan Kulfan Ferenc Lakatos Oto Nakládal Jiří Schlaghamerský Michal Svatoš Jiří Trombik Petr Zábranský Peter Zach Emanuel Kula 《Journal of Applied Entomology》2020,144(6):423-433
Invasive organisms represent great threats to ecosystems and great challenges to forest management. In Europe, the black timber bark beetle (Xylosandrus germanus) is an invasive secondary pest that mostly attacks the logs of felled trees. We showed the invasion history for Europe and using many local surveys, we summarize the current distribution and other available information on X. germanus in the Czech Republic. We report that this species is distributed from the lowlands to the mountains in the Czech Republic; it is widespread in the eastern half of the country, where it is more abundant in the warmer south and southeast areas than in the cooler areas. Most (78%) of the known localities are at elevation below 400 m a.s.l. Although an ice storm greatly increased X. germanus abundance near the border with Austria, its high abundance did not result in damage to standing trees. Presence of X. germanus in the Czech Republic for over 10 years has not led to heavy tree infestation. 相似文献