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Abstract A new species, Sinophasma largum sp. nov., is described from China (Sichuan, Guizhou, Hunan, Hubei and Guangxi Provinces). The type specimens are kept in the Institute of Zoology, Academia Sinica. 相似文献
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Ca2+ inhibited the Mg2+-dependent and K+-stimulated p-nitrophenylphosphatase activity of a highly purified preparation of dog kidney (Na+ + K+)-ATPase. In the absence of K+, however, a Mg2+-dependent and Ca2+-stimulated phosphatase was observed, the maximal velocity of which, at pH 7.2, was about 20% of that of the K+-stimulated phosphatase. The Ca2+-stimulated phosphatase, like the K+-stimulated activity, was inhibited by either ouabain or Na+ or ATP. Ouabain sensitivity was decreased with increase in Ca2+, but the K0.5 values of the inhibitory effects of Na+ and ATP were independent of Ca2+ concentration. Optimal pH was 7.0 for Ca2+-stimulated activity, and 7.8–8.2 for the K+-stimulated activity. The ratio of the two activities was the same in several enzyme preparations in different states of purity. The data indicate that (a) Ca2+-stimulated phosphatase is catalyzed by (Na+ + K+)-ATPase; (b) there is a site of Ca2+ action different from the site at which Ca2+ inhibits in competition with Mg2+; and (c) Ca2+ stimulation can not be explained easily by the action of Ca2+ at either the Na+ site or the K+ site. 相似文献
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Abstract The H2 region, encoding one of the flagellar antigens of Salmonella typhimurium and the controlling elements of phase variation has been subcloned into the broad-host-range plasmid, RP4. Due to a deletion within the H2 region, the 'invertase' normally encoded by the hin gene is absent. This plasmid was transferred into a number of Gram-negative bacteria, and a hin complementary ( din ) activity detected in some. 相似文献
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R. T. Cardé T. C. Baker P. J. Castrovillo 《Entomologia Experimentalis et Applicata》1977,22(3):280-288
Emission of (Z)-8-dodecenyl acetate [7% (E) isomer] from hollow fiber dispensers at 0.15 g/ha/day from 1700 points (units of 10 fibers)/ha effects complete disruption of male Grapholitha molesta (Busck) attraction to synthetic lure and virgin females. Attraction of G. prunivora (Walsh) to synthetic lures is also completely disrupted. Emission of (E,E)-8,10-dodecadien-1-ol at 0.05 g/ha/day from 1700 points/ha effects complete disruption of male Laspeyresia pomonella (L.) attraction to synthetic pheromone, to virgin females and prevents mating with tethered females.
Lepidoptera: Tortricidae: Olethreutinae 相似文献
Résumé L'émission du composé (Z)-8-dodecenyl acetate (7% de l'isomère E 8-12 Ac dans le texte), à la dose de 0,15 g/ha/jour, à partir d'émetteurs formés d'une fibre creuse (type Conrel (R)), répartis en 1700 points/ha, chaque point comportant des unités de 10 fibres, annihile complètement l'attraction du mâle de Grapholitha molesta à l'égard de femelles vierges ou de leures chimiques de synthèse. L'attraction de G. prunivora pour des leures synthétiques est également totalement interrompue.L'émission du composé E8 E10-dodécadien-1-ol (E8 E10-12:OH) à la dose de 0,05 g/ha/jour, à partir de 1700 points/ha, entraîne la destruction totale du comportement attractif de Laspeyresia pomonella pour des hormones de synthèse, ou pour des femelles vierges et empêche l'accouplement avec des femelles non mobiles liées par un système adhésif à un dispositif attractif (pherotrap 1C).
Lepidoptera: Tortricidae: Olethreutinae 相似文献
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K. U. Prasad T. L. Trapane D. Busath G. Szabo D. W. Urry 《Journal of Protein Chemistry》1982,1(3):191-202
The solid phase synthesis of [[1-13C]Phe11]Gramicidin B was successfully achieved using the 9-Fluorenylmethyloxycarbonyl protecting group. There was at least a 30% drop in yield during the adition of the three valines in positions 8, 7 and 6, which is likely due to steric hindrance caused by the steric constraints of the valine side chains. Still, the overall yield of the peptide was comparable with that obtained using thetert-butyloxycarbonyl group for protection. The synthetic Gramicidin B was completely characterized by high-pressure liquid chromatography, circular dichroism, and13C nuclear magnetic resonance spectra. Also reported are the single-channel conductance properties, which compare favorably with those reported earlier and demonstrate the interesting multiplicity of conductance states to be distinquishable from that of Gramicidin A. Thus, these several useful characterizations have been carried out on the same preparation.Abbreviations: IUPAC-IUB Commission recommendations are used in most cases: AcOH, acetic acid; Boc,tert-butyloxycarbonyl; CD, circular dichroism; CMR,13C nuclear magnetic resonance; DCC,N,N'-dicyclohexylcarbodiimide; EtOAc, ethyl acetate; Fmoc, 9-fluorenylmethyloxycarbonyl; HOBt, 1-hydroxybenzot iazole; HPLC, high-pressure liquid chromatography; MeOH, methanol;-OSu,N-hydroxysuccinimide ester; TFA, trifluoroacetic acid; t.l.c., thin-layer chromatography; Me2SO-d6, dimethyl-d6-sulfoxide; CMA, chloroform-methanol-acetic acid; DMF, dimethyl for-mamide; DIEA, diisoproprylethylamine. 相似文献
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Christopher W GlynnMark M Turnbull 《Inorganica chimica acta》2002,332(1):92-100
2,6-Bis(1-triazolo)pyridine (1) was synthesized and characterized via IR and NMR. The regiochemistry of the compound was confirmed via single crystal X-ray analysis of the hydrochloride salt. A series of insoluble complexes of the general formulae M(1)2(X)2 or M(1)(X)2 [M=Co(II), Ni(II), Cu(II); X=ClO4, BF4, Cl] were prepared and their structures interpreted in light of infrared spectra and composition analysis. The results suggest that first row transition metals are not chelated by 1, but rather form extended coordination polymeric networks. A second family of complexes was prepared using 2,6-bis(1-imidazolo)pyridine to support this interpretation. 相似文献
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The classical E2-P intermediate of (Na+ + K+)-ATPase dephosphorylates readily in the presence of K+ and is not affected by the addition of ADP. To determine the significane in the reaction cycle of (Na+ + K+)-ATPase of kinetically atypical phosphorylations of rat brain (Na+ + K+)-ATPase we compared these phosphorylated components with the classical E2-P intermediate of this enzyme by gel electrophoresis. When rat brain (Na+ + K+)-ATPase was phosphorylated in the presence of high concentrations of Na+ a proportion of the phosphorylated material formed was sensitive to ADP but resistant to K+. Similarly, if phosphorylation was carried out in the presence of Na+ and Ca2+ up to 300 pmol/mg protein of a K+-resistant, ADP-sensitive material were formed. If phosphorylation was from [γ-32P]CTP up to 800 pmol 32P/mg protein of an ADP-resistant, K+-sensitive phosphorylated matterial were formed. On gel electrophoresis these phosphorylated materials co-migrated with authentic Na+-stimulated, K+-sensitive, E2-P-phosphorylated intermediate of (Na+ + K+)-ATPase, supporting suggestions that they represent phosphorylated intermediates in the reaction sequence of this enzyme. 相似文献
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The K+-dependent p-nitrophenylphosphatase activity catalyzed by purified (Na+ + K+)-ATPase from pig kidney shows substrate inhibition (Ki about 9.5 mM at 2.1 mM Mg2+). Potassium antagonizes and sodium favours this inhibition. In addition, K+ reduces the apparent affinity for substrate activation, whereas p-nitrophenyl phosphate reduces the apparent affinity for K+ activation. In the absence of Mg2+, p-nitrophenyl phosphate, as well as ATP, accelerates the release of Rb+ from the Rb+ occluded unphosphorylated enzyme. With no Mg2+ and with 0.5 mM KCl, trypsin inactivation of (Na+ + K+)-ATPase as a function of time follows a single exponential but is transformed into a double exponential when 1 mM ATP or 5 mM p-nitrophenyl phosphate are also present. In the presence of 3 mM MgCl2, 5 mM p-nitrophenyl phosphate and without KCl the trypsin inactivation pattern is that described for the E1 enzyme form; the addition of 10 mM KCl changes the pattern which, after about 6 min delay, follows a single exponential. These results suggest that (i) the shifting of the enzyme toward the E1 state is the basis for substrate inhibition of the p-nitrophenulphosphatase acitivy of (Na+ + K+)-ATPase, and (ii) the substrate site during phosphatase activity is distinct from the low-affinity ATP site. 相似文献
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Alan C. Swann 《Archives of biochemistry and biophysics》1983,221(1):148-157
The effects of temperature on interactions between univalent cations or ATP and the p-nitrophenylphosphatase activity associated with brain (Na+,K+)-ATPase were examined. The apparent affinity for K+ activation under conditions favoring the moderate affinity site was temperature dependent, increasing with decreasing temperature. A comparison of univalent cations showed that the negative apparent ΔH and ΔS for cation binding increased with increasing apparent cation affinity. In contrast to the case with the moderate affinity sites, apparent affinity for the high affinity K+ site was independent of temperature. As temperature decreased, properties of moderate affinity site binding approached those of the high affinity site. The temperature dependence of ATP inhibition was opposite to that for K+ activation, with positive apparent ΔH and ΔS. The apparent ΔH and ΔS for cation binding approached those for the overall conformational change to K+-sensitive enzyme as cation affinity increased. These data suggest that E2, the K+-sensitive form of (Na+,K+)-ATPase, is stabilized by forces that require a decrease in entropy, explaining the predominant existence of E1 at physiologic temperatures. A conformational change leading to stabilization of E2 at higher temperatures can be produced by binding of univalent cations to a moderate affinity, presumably intracellular, site. This effect is counteracted by ATP. ATP also appears to alter the selectivity of this site to favor Na+ over K+ binding. 相似文献
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Brian Colman 《Journal of phycology》1978,14(4):434-437
The claim that Chlorella sp. (CCAP 211/8p), sometimes referred to as C. fusca, Shihira and Krauss, does not excrete glycolate has been reexamined. Chlorella sp. grown on 5% CO2in air, excreted glycolate when incubated in light in 10 mM bicarbonate. Excretion ceased 30–60 min after transfer of the cells to air and no excretion could be detected with air-grown cells or with cells grown on 5% CO2in media buffered at pH 8.0. Incubation with 10 mM isonicotinyl hydrazide, a glycolate pathway inhibitor, caused excretion in air-grown cells and stimulated excretion in CO2-grown cells indicating that both the rate of glycolate synthesis and metabolism is higher in CO2grown cells than in air-grown cells. Enhanced glycolate synthesis and excretion in CO2-grown cells is correlated with law photosynthetic rate in 10 mM bicarbonate, and the photosynthetic rate of these cells doubles over a period of 2–2.5 h after initial transfer from high CO2to bicarbonate. This correlation of photosynthetic induction with cessation of glycolate excretion is similar to that reported in a bluegreen alga and thought to occur in other green algae. These results indicate that glycolate excretion and its regulation in this species of Chlorella is not different from that in other algae. 相似文献
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A 3,4-dehydroproline analogue of tuftsin (L-Thr-L-Lys-L-Pro-L-Arg) was prepared by the solid phase synthetic method. Following reversed-phase high performance liquid chromatography (HPLC) purification, the analogue was compared to tuftsin for its ability to enhance the chemotactic, bactericidal and phagocytic activities of polymorphonuclear leukocytes (PMN). Both tuftsin and [Δ3-pro3]-tuftsin elicited a similar significant chemotactic effect at a concentration of 10 μg/ml. A slight suppression of the chemotactic activity was observed with tuftsin at 10?3 μg/ml and with [Δ3-pro3]-tuftsin at concentrations of 10?3, 10?2 (significant) and 10?1 μg/ml. Although similar bactericidal activities were observed for both peptides, PMN exposed to [Δ3-pro3]-tuftsin exhibited increased phagocytic indicies 2–4 times that of tuftsin-treated PMN at concentrations of 0.4, 0.6 and 1.0 μg/ml. 相似文献
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Peter Kutschy Aneta Salayová Zuzana Čurillová Tibor Kožár Roman Mezencev Ján Mojžiš Martina Pilátová Eva Balentová Pavel Pazdera Marián Sabol Michaela Zburová 《Bioorganic & medicinal chemistry》2009,17(10):3698-3712
New analogs of indole phytoalexin 1-methoxyspirobrassinol methyl ether have been designed by replacement of its 2-methoxy group with 2-(substituted phenyl)amino group. Synthesized by spirocyclization methodology, trans- and cis-diastereoisomers of target compounds were isolated and evaluated as potential anticancer and antimicrobial agents. Their molecular geometries were refined by ab initio minimizations. Pharmacophore modeling and QSAR studies were performed in order to correlate their molecular structure and biological activity. 相似文献
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M.P.L. Caton G. Darnbrough D.J. Hambling R. Jordan T. Parker 《Prostaglandins & other lipid mediators》1979,18(4):569-576
(±)-11-Deoxy-10-hydroxy-PGE1 methyl ester (Va) has been synthesised conjugate addition of the cuprate (III) to the 5-tetrahydropyranyloxycyclopentenone (IId).Va was found to be 0.1 times as active as PGE1 as a uterine stimulant in the anaesthetized pregnant rat, 0.25 times as active as PGE1 in causing vasodepression in the anaesthetized cat, and approximately equiactive to PGE1 in inducing bronchoconstriction. 相似文献
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Excretion of minerals by the NaCl-resistant and comparatively cadmium-resistant tree Tamarix aphylla (L.) Karst, was investigated. Cd2+ was excreted by plants exposed for 1–10 days to 9 or 45 μ M Cd2+ solutions. Excretion of this toxic ion increased considerably with time but was less than 5% of the quantities that had been accumulated in the shoots. Excretion of Na+ and Cl− was positively correlated with NaCl concentration (1.5, 10, 50 m M ) of the medium. The Na+ /Cl− ratios of the excrete were positively correlated with the concentration of the treatment solution. Ca2+ excretion decreased with increasing NaCl concentrations of the solution. Excretion of K+ and Mg2+ was only little affected by NaCl. Excretion of Li+ occurred whenever this element was supplied in the uptake solution; daily excretion rates of Li+ increased with time. The ecological significance of excretion is discussed in relation to the low selectivity of the mechanism in T. aphylla . 相似文献