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1.
Summary Two insect development inhibitors againstDrosophila melanogaster have been isolated from the leaves ofX. canadense and identified as xanthumin and 8-epi-xanthatin.Search for Insect Development Inhibitors in Plants, IV. Part III, Heterocycles10, 117 (1978).This investigation was supported in part by grants (No. 056141 and No. 376065) from the Ministry of Education of Japan. The authors express their sincere thanks to Prof. Junkichi Iwasa of this department for his encouragement and to Dr Kenji Uneyama, Department of Industrial Chemistry of this University, for13C-NMR measurements.  相似文献   

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Cyclic AMP was determined during the development of the diptera Ceratitis capitata. The concentration of the nucleotide reaches a peak at apolysis with a sharp decline in the pharate adult stage. A gradual increase takes place through the longevity of adult stage reaching a maximum plateau at the end of life.  相似文献   

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Growth cones experience many different cues in their journey to their final target. They can respond to a variety of attractive and repulsive cues that can be secreted or cellular. These cues are generated by a wide range of cell types. One subset of cells that play an important role in growth cone guidance are glial cells. Glia secrete guidance cues and express cellular cues on their surface that guide axonal outgrowth. In doing so, glia can act as intermediate targets in growth cone guidance, a process that is conserved between vertebrate and invertebrate nervous systems. Recent work in grasshopper, Drosophila and moth nervous system development has underscored the importance of the instructive role glia play during axonal outgrowth.  相似文献   

4.
The emerging critical implications of Rho/Rho-kinase (ROCK) signaling in neurodegenerative diseases, glaucoma, renoprotection, diabetes and cancer have sparked growing interest in the pharmacological potential of ROCK inhibitors beyond their current application in cardiovascular disease. This article discusses the therapeutic benefits of novel ROCK inhibitors in development, and highlights the recent advances in the current understanding of disease-dependent and isoform-specific functions of ROCK and their potential impact on future therapeutic strategies.  相似文献   

5.
We have examined the effects of seven protein kinase inhibitors (staurosporine, genistein, methyl 2,5-dihydroxycinnamate, tyrphostins B44 and B46, lavendustin A and R03) on the erythrocytic cycle of the malaria parasite,Plasmodium falciparum. One (staurosporine) strongly inhibits serine/threonine kinases, but the remainder all exhibit a strong preference for tyrosine kinases. We have been able to discriminate between effects on invasion and on intraerythrocytic development. All reagents impeded development of intraerythrocytic parasites, though at widely differing concentrations, from the sub-micromolar to the millimolar. Several inhibitors, including staurosporine, also reduced invasion. The phosphatase inhibitor, okadaic acid, had a strong inhibitory effect both on invasion and development. The regulation of malaria development by phosphorylation or dephosphorylation reactions at several points in the blood-stage cycle is implied.  相似文献   

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C F Curtis 《Experientia》1975,31(10):1139-1141
Published data on an experimental release of Culex pipiens carrying a male-linked translocation are re-examined and it is shown that the steady decline in translocation frequency after termination of releases agrees with theoretical expectations, because of the selective disadvantage of translocation heterozygote males. Systems based on negative heterosis or meiotic drive are considered whereby it might be possible to prolong the population control which would be achieved by a short term release.  相似文献   

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Thick and thin filaments of synchronous and asynchronous insect flight muscles were separated by density gradient centrifugation. A good release of myofilaments from myofibrils was obtained by sonication of myofibrils in relaxing solution with pH 6.1 (locust), pH 6.4 (honeybee) and pH 6.6 (fleshfly), respectively. Thick filaments but not thin filaments were dissolved, if sucrose gradient centrifugation was used to separate the filaments. Thus, sucrose gradients are the medium of choice if actin filaments are to be purified. Glycerol-containing gradients selectively dissolved myosin filaments from fleshfly muscles. The stability of the myosin filaments of all muscles was sufficient in gradients with 10–30% formamide.  相似文献   

9.
When the isolated head-fold stage rat embryonic ectoderm is grafted under the kidney capsule, it gives rise to a new mesenchyme with the capacity to differentiate into mesodermal tissues.  相似文献   

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Zusammenfassung Substitution einerN 6-Aminogruppe eines zyklischen Nukleotids führt zu einer erh?hten Hemmwirkung des Nukleotids gegenüber Adenyl-Cyclase von Meerschweinchenlungen, w?hrend dieN 6-Amino-Substition von Adenosin-Analogen eine herabgesetzte Inhibitionswirksamkeit gegenüber demselben Enzym zur Folge hat. Die experimentellen Daten führen zu dem Schluss, dass der Inhibitionsmechanismus gegenüber Cyclase für beide Verbindungstypen verschieden ist.   相似文献   

12.
Dewaxed leaf surface extracts of 12 plants from Hokkaido, prepared by dipping fresh leaves in chloroform for 3 min, were used in a choice leaf-disk bioassay against larvae of the tobacco cutwormSpodoptera litura. Activity was found only in the extract ofSenecio cannabifolius, a very successful weed in Hokkaido. Individual fractions of the extract, however, were not active. Incorporation of the individual fractions of the surface extracts as well as fractions of the methanolic extracts of the leaf residue into an artificial diet fed to neonateS. litura led to the isolation of ethyl (1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate, the major surface compound, as the active principle. This compound was also present in the methanolic extract of the leaf residue together with methyl (1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl) acetate, which had the same growth inhibitory effect on the larvae. The presence of these compounds in the foliar surface and tissue suggests a defensive role against herbivores.  相似文献   

13.
Polyamines at physiological concentrations activate AMP nucleosidase from Azotobacter vinelandii. Biological significance of the activation is discussed in relation to the control of adenylate energy charge and the purine nucleotide synthesis in prokaryotes.  相似文献   

14.
Carrageenin-induced oedema in rats was potentiated by oral administration of (4R)-3-[(2S)-3-mercapto-2-methylpropanoyl]-4-thiazolidinecarboxylic acid (SA291) and related sulfhydryl compounds, and the effect was closely correlated with their potencies as inhibitors of angiotensin-converting enzyme in vivo.  相似文献   

15.
Zusammenfassung Die Lanthanide HolmiumIII und PraseodymiumIII hemmen den aktiven Ca-Transport der Erythrozytenmembran. Eine Konzentration von etwa 10–4 M ergibt 50% Hemmung. Eine Ca + Mg aktivierte Membran-ATPase des Erythrozyten zeigt gegenüber diesen beiden Kationen ungefähr die gleiche Empfindlichkeit wie der Transport.  相似文献   

16.
B Asking  U Delfs  N Emmelin  P Gj?rstrup 《Experientia》1979,35(10):1336-1337
A slow, long-lasting 'degeneration secretion' from the parotid gland was brought about in anaesthetized rats by section of the auriculo-temporal nerve 16--19 h in advance. This parasympathetic background activity greatly increased the secretion of amylase elicited by sympathetic nerve stimulation.  相似文献   

17.
Tyrosinase is known to be a key enzyme in melanin biosynthesis, involved in determining the color of mammalian skin and hair. Various dermatological disorders, such as melasma, age spots and sites of actinic damage, arise from the accumulation of an excessive level of epidermal pigmentation. In addition, unfavorable enzymatic browning of plant-derived foods by tyrosinase causes a decrease in nutritional quality and economic loss of food products. The inadequacy of current conventional techniques to prevent tyrosinase action encourages us to seek new potent tyrosinase inhibitors. This article overviews the various inhibitors obtained from natural and synthetic sources with their industrial importance.Received 9 February 2005; received after revision 4 April 2005; accepted 14 April 2005  相似文献   

18.
Summary Both Mg2+-ATPase and HCO 3 -stimulated ATPase activity were inhibited by sodium azide and to a lesser extent ethacrynic acid and amiloride. 1 mM DNP stimulated Mg2+-ATPase activity by 22% and HCO 3 -stimulated ATPase activity by 7%.  相似文献   

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