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1.
Methacholine, nicotine and succinylcholine stimulated the phospholipase A2-acylation system of synaptic membranes isolated from the cerebral cortex of guinea pig. Stimulation by acetylcholine was partially blocked by atropine and by D-tuberocurarine respectively, indicating both muscarinic and nicotinic stimulation. Muscarinic stimulation by acetylcholine was greater than -isotinic stimulation, and stimulation by acetylcholine was completely blocked by a combip, or;. and n-tuberocurarine. The phospholipase A2-acylat tem was stimulated by phenylcphrine., id. Cqxoterenoi. Stimulation by noradrenaline was J-. tidlr, by phenoxybenzamine and pindalol i:spectively, indicating both 8-adrenergic and P-adrenergic ztimulation. n-Adrenergic stimulation by noradrenaline was greater than P-adrenergic-stimulation. 5 -mlation by noradrenaline was completely blocked by a combination of phenoxybenzamins and pindalol. Stimulation of both acylation and phospholipid hydrolysis, by 5-hydroxytryptamine and histamine were partially blocked by methysergide and diphenhydramine respectively. Stimulation by dopamine was blocked by halopcridol. Stimulation by y-aminobutyric acid was partially blocked by strychnine and by picrotoxin. Dichloroisoproterenol, atropine, methysergidr, diphenhydramine, strychnine, picrotoxin and eserine, at relatively high concentrations (1 mM), stimuhted the phospholipase A2-acylation system. Synergistic stimulations of both acylatior, and hydrolysis of phosphatidylcholine, were observed by adenosine combined with noradrenaline, 5-hydroxytryptamine, histamine, dopamine or yaminobutyric acid, respectively. In the presence of ATP-MgCI, synergistic stimulations of the hydrolysis of phosphatidyicholine were observed after 30 s by noradrenaline combined with 5-hydroxytryptamine, histamine, dopamine, aminobutyric acid or carbamoylcholine respectively. In the presence of GTP-MgC12 synergistic stimulations were obtained by cdrbamoylcholine combined with noradrenaline. 5-hydroxytryptamine. histamine, dopamine or y-aminobutyric acid, respectively. In the presence of ATP-MgC12 plus GTP-MgC12, stimulation by noradrenaline and one other agonist including 5-hydroxytryptamine, histamine, dopamine, y-aminobutyric acid or carbamoylcholine were close to additive.  相似文献   

2.
Book reviewed in this article:
The Voyage of Charles Darwin: His Autobiographical writings, selected and arranged by Christopher Railing.
Penguin Nature Guides: Fungi of Northern Europe, Vols I & II, by S. Nilsson &; O. Persson; illustrated by B. Mossberg
Penguin Nature Guides: Plant Communities, by Anned Biilow-Olsen, illustrated by Susanne Larsen; translated from the Danish by Joan Tate; edited and adapted by Francis Rose.
Penguin Nature Guides: Fishes of the British and Northern European Seas, by J. Moller Christensen; illustrated by Bente Nystrom; translated from the Danish by Gwynne Vevers; edited and adapted by Gwynne Vevers and Philip Orkin.
Birds of Wood, Park and Garden, text and illustrations by Lars Jonsson; translated from the Swedish by Roger Tanner
Birds of Sea and Coast, text and illustrations by Lars Jonsson; translated from the Swedish by Roger Tanner  相似文献   

3.
Principles of Crop Improvement, by N. W. Simmonds
Marine Organisms – Genetics, Ecology & Evolution, edited by B. Battaglia & J. A. Beardrnore
Arthropod Phytogeny, edited by A. P. Gupta. Van Nostrand Reinhold
Field Guide to the Land Snails of Britain and North-west Europe, by M. P. Kernev & R. A. D. Cameron; illustrated by Gordon Riley
Key to the Fishes of Northern Europe, by Alwync Wheeler; illustrated by Peter Stebbing; maps by F. Rodney Fraser
Penguin Nature Guides: The Biology of Flowers, by Eigil Holm; illustrated by Thomas BredsdorfT; translated by Joan Tate; edited & adapted by Ronald Melville
Penguin Nature Guides: Orchids of Northern Europe, by Sven Nilsson; illustrated by Bo Mossberg; edited & adapted by P. Francis Hunt
A New Look at the Dinosaurs, by Alan Charig. Heinemann  相似文献   

4.
植物生长调节物质IP-1号对木薯产量及其生物性状的影响   总被引:4,自引:0,他引:4  
1990和1991年在木薯(ManihotesculentaCrantz)生长期以植物生长调节物质IP-1号0,20,30和40ppm进行叶面喷洒,结果表明:30ppm处理可使木薯块根产量平均增加54.44%,块根淀粉含量平均提高20.81%。单株最大薯重提高31.55%,块根数增加21.17%,块根长度增长17.62%,地上部鲜重增加34.36%,植株高度增加4.36%,植株收获期保留青叶数增加19.42%,主茎直径增加6.26%,块根直径增加2.58%,叶片的叶绿素和蛋白质含量分别提高5.57%和25.96%,叶片光合作用强度提高15.86%,而对主茎高度、主茎节数没有明显影响。  相似文献   

5.
The mechanism of metallothionein (MT) induction of the liver by endotoxin, which is mediated by a factor secreted by endotoxin-stimulated macrophages, was studied in vitro. MT induction of the liver cells by the endotoxin-stimulated macrophage conditioned medium was inhibited by a monoclonal antiepidermal growth factor (EGF) / transforming growth factor-alpha (TGF-alpha) receptor antibody, which acts as an antagonist of EGF and TGF-alpha. MT was induced by the substance, which was adsorbed by polyclonal antibody to TGF-alpha, but not by a monoclonal antibody to EGF, in the conditioned medium of endotoxin-stimulated macrophages. These results suggest that TGF-alpha secreted by macrophages is involved in MT induction by endotoxin.  相似文献   

6.
Book reviewed in this article:
Flowers of the Himalaya , by Oleg Polunin and Adam Stainton.
A Guide to the Vegetation of Britain and Europe , by Oleg Polunin and Martin Walters.
The Experimental Biology of Bryophytes, edited by A. F. Dyer & J. G. Duckett.
A Birdwatcher's Miscellany, edited by Rob Hume.
The Moths and Butterjlies of Great Britain and Ireland, Volume 10, Noctuidae (Part II) and Agaristidae, edited by J. Heath.
Atlas of Butterjlies in Britain and Ireland, by J. Heath, E. Pollard & J. A. Thomas.
Colour Identification Guide to Butterjlies of the British Isles, revised edition by T. G. Howarth.
The World of Butterjlies, An Illustrated Encyclopaedia, by V. Sbordoni & S.Forestiero.
Colour Identijcation Guide to Moths of the British Isles, by Bernard Skinner.
The Biology of Buttegies, edited by R. I. Vane-Wright & P. R. Ackery.
Australian Grasses, by Nancy T. Burbidge, revised by Surrey W. L. Jacobs.
Collins Guide to Grasses, Sedges, Rushes and Ferns, by R. Fitter & A. Fitter. Collins.
Grasses of the Soviet Union, by N. N. Tsvelev, edited by A. A. Fedorov.
The European Garden Flora, Volume 2, Monocotyledons (Part ZZ), edited by S. M Walters et al.
Grasses, 3rd edition, by C. E. Hubbard, revised by J. C. E. Hubbard.  相似文献   

7.
Intact cells of the marine bacterium Alteromonas haloplanktis 214 oxidized NADH, added to the suspending medium, by a process which was stimulated by Na+ or Li+ but not K+. Toluene-treated cells oxidized NADH at three times the rate of untreated cells by a mechanism activated by Na+ but not by Li+ or K+. In the latter reaction, K+ spared the requirement for Na+. Intact cells of A. haloplanktis oxidized ethanol by a mechanism stimulated by either Na+ or Li+. The uptake of alpha-aminoisobutyric acid by intact cells of A. haloplanktis in the presence of either NADH or ethanol as an oxidizable substrate required Na+, and neither Li+ nor K+ could replace it. The results indicate that exogenous and endogenous NADH and ethanol are oxidized by A. haloplanktis by processes distinguishable from one another by their requirements for alkali metal ions and from the ion requirements for membrane transport. Intact cells of Vibrio natriegens and Photobacterium phosphoreum oxidized NADH, added externally, by an Na+-activated process, and intact cells of Vibrio fischeri oxidized NADH, added externally, by a K+-activated process. Toluene treatment caused the cells of all three organisms to oxidize NADH at much faster rates than untreated cells by mechanisms which were activated by Na+ and spared by K+.  相似文献   

8.
Formaldehyde can be metabolized primarily by two different pathways, one involving oxidation by the low-Km mitochondrial aldehyde dehydrogenase, the other involving a specific, glutathione-dependent, formaldehyde dehydrogenase. To estimate the roles played by each enzyme in formaldehyde metabolism by rat hepatocytes, experiments with acetaldehyde and cyanamide, a potent inhibitor of the low-Km aldehyde dehydrogenase were carried out. The glutathione-dependent oxidation of formaldehyde by 100,000g rat liver supernatant fractions was not affected by either acetaldehyde or by cyanamide. By contrast, the uptake of formaldehyde by intact mitochondria was inhibited 75 to 90% by cyanamide. Acetaldehyde inhibited the uptake of formaldehyde by mitochondria in a competitive fashion. Formaldehyde was a weak inhibitor of the oxidation of acetaldehyde by mitochondria, suggesting that, relative to formaldehyde, acetaldehyde was a preferred substrate. In isolated hepatocytes, cyanamide, which inhibited the oxidation of acetaldehyde by 75 to 90%, produced only 30 to 50% inhibition of formaldehyde uptake by cells as well as of the production of 14CO2 and of formate from [14C]formaldehyde. The extent of inhibition by cyanamide was the same as that produced by acetaldehyde (30-40%). In the presence of cyanamide, acetaldehyde was no longer inhibitory, suggesting that acetaldehyde and cyanamide may act at the same site(s) and inhibit the same formaldehyde-oxidizing enzyme system. These results suggest that, in rat hepatocytes, formaldehyde is oxidized by cyanamide- and acetaldehyde-sensitive (low-Km aldehyde dehydrogenase) and insensitive (formaldehyde dehydrogenase) reactions, and that both enzymes appear to contribute about equally toward the overall metabolism of formaldehyde.  相似文献   

9.
Metallothionein inhibits peroxynitrite-induced DNA and lipoprotein damage   总被引:13,自引:0,他引:13  
Previous studies have demonstrated that metallothionein functions as an antioxidant that protects against oxidative DNA, protein, and lipid damage induced by superoxide anion, hydrogen peroxide, hydroxyl radical, and nitric oxide. The present study was undertaken to test the hypothesis that metallothionein also protects from DNA and lipoprotein damage induced by peroxynitrite, an important reactive nitrogen species that causes a diversity of pathological processes. A cell-free system was used. DNA damage was detected by the mobility of plasmid DNA in electrophoresis. Oxidation of low density lipoprotein was measured by a thiobarbituric acid-reactive substance, which was confirmed by lipid hydroperoxide assay. Plasmid DNA damage and low density lipoprotein oxidation were induced by 3-morpholinosydnomine, which produces peroxynitrite through the reaction between nitric oxide and superoxide anion or by synthesized peroxynitrite directly. DNA damage by 3-morpholinosydnomine was prevented by both metallothionein and superoxide dismutase, whereas the damage caused by peroxynitrite was prevented by metallothionein only. The oxidation of low density lipoprotein by 3-morpholinosydnomine and peroxynitrite was also significantly inhibited by metallothionein. This study thus demonstrates that metallothionein may react directly with peroxynitrite to prevent DNA and lipoprotein damage induced by this pathological reactive nitrogen species.  相似文献   

10.
The purpose of this study was to compare the accuracy, precision, and bias of fat mass (FM) as assessed by dual-energy X-ray absorptiometry (DXA), hydrostatic weighing (HW), air-displacement plethysmography (PM) using the BOD POD body composition system and total body water (TBW) against the four-compartment (4C) model in 25 children (11.4 +/- 1.4 yr). The regression between FM by the 4C model and by DXA deviated significantly from the line of identity (FM by 4C model = 0.84 x FM by DXA + 0.95 kg; R(2) = 0.95), as did the regression between FM by 4C model and by TBW (FM by 4C model = 0. 85 x FM by TBW - 0.89 kg; R(2) = 0.98). The regression between FM by the 4C model and by HW did not significantly deviate from the line of identity (FM by 4C model = 1.09 x FM by HW + 0.94 kg; R(2) = 0. 95) and neither did the regression between FM by 4C (using density assessed by PM) and by PM (FM by 4C model = 1.03 x FM by PM + 0.88; R(2) = 0.97). DXA, HW, and TBW all showed a bias in the estimate of FM, but there was no bias for PM. In conclusion, PM was the only technique that could accurately, precisely, and without bias estimate FM in 9- to 14-yr-old children.  相似文献   

11.
12.
A prothrombinase complex of mouse peritoneal macrophages   总被引:3,自引:0,他引:3  
Addition of prothrombin to mouse peritoneal macrophages in vitro resulted in the formation of a thrombin-like enzyme, as demonstrated by use of the luminogenic peptide substrate S-2621. The prothrombinase activity was sedimented by high-speed centrifugation following homogenization of the cells and was abolished by treatment of the cells with the nonionic detergent Triton X-100 at 0.02% concentration. Moreover, the activity was drastically reduced by maintaining cultures in the presence of warfarin and, presumably due to competitive substrate inhibition, by adding S-2222, a chromogenic peptide substrate for Factor Xa. These findings suggest that prothrombin cleavage is catalyzed by Factor Xa at the macrophage surface. The generated thrombin was inhibited by antithrombin, and this reaction was accelerated by heparin with high affinity for antithrombin but not by the corresponding oligosaccharides composed of 8-14 monosaccharide units. Such oligosaccharides which are capable of accelerating the inactivation of Factor Xa by antithrombin, inhibited thrombin formation from prothrombin in the macrophage cultures, presumably by promoting inactivation by antithrombin of Factor Xa in a prothrombinase complex. Activation of the macrophage coagulation system, as proposed to occur in certain inflammatory conditions, thus may be modulated at various levels by heparin, or heparin oligosaccharides, released from mast cells.  相似文献   

13.
Book reviewed in this article:
A World Like Our Own—Man and Nature in Madagascar , by Alison Jolly.
Vertebrate Limb Regeneration , by H. Wallace.
Statistical Methods in Biology , by N. T.J. Bailey
Conservation and Evolution , by O. H. Frankel & M. E. Soule
Evolution in Age-structured Populations by B. Charlesworth
Essential Biology , by Herbert T. Hendrickson
Flora Suzakiensis , edited by Biological Laboratory, Imperial Household
Phylogenetic Patterns and the Evolutionary Process , by N. Eldredge & J. Cracraft
Excursion Flora of the British Isles , by A. R. Clapham, T. G. Tutin & E. F. Warburg
Whales , by W. N. Bonner
Les Chevaux, Fossiles et Actuels , by V. Eisenmann
Freshwater Snails of Africa and their Medical Importance , by David S. Brown
Symbiosis in Cell Evolution , by Lynn Margulis
Vegetation Dynamics , by J. Miles  相似文献   

14.
Exposure of perfused rat livers to zymosan, arachidonic acid and phenylephrine, but not to latex particles, induces pronounced oxygen uptake, glycogenolysis and Ca2+ mobilization. The oxygen uptake induced by arachidonic acid and by zymosan remains elevated even after the agents have been removed. NaN3 was found to be much more effective in inhibiting the oxygen uptake induced by phenylephrine than that induced by zymosan or arachidonic acid. Glucose release induced by zymosan and by arachidonic acid reaches a maximum after about 2 min and then declines very rapidly even while the agents are still being infused. In contrast, glucose release induced by phenylephrine remains elevated for the duration of the infusion. Ca2+ fluxes induced by arachidonic acid are similar to those induced by phenylephrine in that efflux occurs when the agent is administered and influx occurs only when the agent is removed. This contrasts to the Ca2+ flux changes induced by zymosan where both Ca2+ efflux and Ca2+ influx occur even while zymosan is still being infused. Glucose release induced by zymosan is inhibited by bromophenacylbromide and nordihydroguaiaretic acid, but not by indomethacin. Indomethacin, however inhibits the arachidonic-acid-induced glucose release which is also inhibited by nordihydroguaiaretic acid but not by bromophenacylbromide. Indomethacin inhibits also the arachidonic-acid-induced Ca2+ flux changes whereas the zymosan- and the phenylephrine-induced Ca2+ flux changes are not inhibited by the cyclooxygenase inhibitor. The data presented in this paper suggest that in the perfused rat liver the zymosan-induced glycogenolysis, as well as the Ca2+ flux changes and glycogenolysis induced by arachidonic acid, are mediated by eicosanoids.  相似文献   

15.
Book reviewed in this article:
Taxonomy of Economic Seaweeds: With reference to some Pacific and Caribbean Species, 2 edited by Isabella A. Abbott. La Jolla
Botanic Gardens and the World Conservation Strategy edited by D. Bramwell, O. Hamann, V. Heywood & H. Synge
Introduction to Ecological Biochemistry 3rd ed., by J. B. Harborne
A monographic study of the genus Rosularia (Crassulaceae) by Urs Eggli
The Photographic Guide to Identify Mediterranean Wild Flowers by Roger Phillips assisted by Martin Rix and Nicky Fox
The Photographic Guide to Identify Mediterranean Wild Flowers by Roger Phillips assisted by Martin Rix and Nicky Fox
Conserving the Wild Relatives of Crops by Erich Hoyt.
Somatic Cell Genetics of Woody Plants edited by M. R. Ahuja
Indian Journal of Natural Rubber Research
Dictionary of Weeds of Eastern Europe by G. Williams and K. Hunyadi
Nutrition of the Angiosperm Embryo by David R. Murray.
Plant Pigments edited by T. W. Goodwin.
Panbiogeography edited by R. Craw & G. Sermonti
Saxifrages of Europe: with notes on African, American and some Asiatic species by D. A. Webb & R. J. Gornall  相似文献   

16.
目的比较ELISA(enzyme-linked immunosorbent assay)、IFA(immuno-fluorescence assay)和WB(Western blot)三种方法在大鼠仙台病毒血清学检测中的差异。方法仙台病毒蛋白抗原经凝胶电泳分离转移后用于血清学检测的WB方法;使用IFA、ELISA方法对20份无菌大鼠、227份SPF大鼠以及63份清洁级大鼠送检血清样品进行检测,阳性及可疑样品用WB方法进行了验证。结果 20份无菌大鼠血清样品被3种方法检测为仙台病毒抗体阴性;SPF级大鼠样品被IFA方法判定为阴性,1.32%(3/227)被ELISA方法判定为阳性,其中有2/3被WB确认为阳性;ELISA、IFA和WB在清洁级大鼠样品中检出仙台病毒的阳性率分别为为18.12%、11.34%和15.87%。结论三种检测方法灵敏度从高到低依次为ELISA、WB和IFA。WB方法可作为IFA和ELISA难以确定结果的替代方法。  相似文献   

17.
Three new species of Desmoscolex , found in samples from Yonge Reef, Lizard Island, Nymphe Island and between One Tree Isles and Wistari Reef are described: D. australiens sp.n., characterized by the head-shape with naked semi-circular anterior part, by the jointed cephalic setae inserted close to the anterior extremity and by the shape of the gubernaculum with less sclerotized proximal part; D. membranosas sp.n. close to D. granulatus Decraemer, 1974, but differing from it by the presence of a partly disconnected circumoral membrane and by the oval amphids not reaching the extreme anterior end; D. yongei sp.n. resembling D. americanus Chitwood, 1936, but differing from it by the longer and more slender spicules, by the presence of fine spines on the secondary rings, by the head-shape without a truncated anterior end and by the almost circular amphids.  相似文献   

18.
1. Control of enzyme formation has been examined in the pathways degrading mandelate and p-hydroxymandelate in Pseudomonas fluorescens. 2. The first three enzymes form a group which is common to both pathways and which is co-ordinately induced or repressed. The genes controlling these enzymes are assumed to form a ;regulon'. This group of enzymes is induced by mandelate or p-hydroxymandelate and repressed by benzoate and by p-hydroxybenzoate (the immediate end products resulting from the action of this group of enzymes). 3. Repression is independently exerted by end products of enzymes controlled by succeeding regulons, i.e. by catechol, by protocatechuate and finally by succinate and acetate. 4. The pattern is repeated further along the pathway, so that benzoate oxidase (controlled by the second regulon) is repressed by its immediate end product, catechol, and again by succinate and acetate. 5. Pyrocatechase, an enzyme controlled by the third regulon, is repressed by succinate and acetate. 6. There is a parallel system of multi-sensitive repression mechanisms controlling production of the enzymes that degrade the hydroxy compounds. Again, the enzymes of each regulon are repressed by the immediate end product of their action and by the end products of each succeeding group of enzymes. 7. Repressor activity appears to be exerted by compounds that are likely to occur as such in the external environment or that occur at points of convergence of the degradative pathways of the cell. 8. The net effect of this control system, involving both induction and end-product repression, appears to be that cells will not form inducible degradative enzymes if the end products are already being supplied from without or are being produced by degradation of some alternative source of carbon and energy.  相似文献   

19.
Inducible binding proteins for C4-dicarboxylic acids (DBP) and glucose (GBP) were isolated from Pseudomonas aeruginosa by extraction of exponential-phase cells with 0.2 M MgC12 (pH 8.5) and by an osmotic shock procedure without affecting cell viability. DBP synthesis was induced by growth on aspartate, alpha-ketoglutarate, succinate, fumarate, malate, and malonate but not by growth on acetate, citrate, pyruvate, or glucose. Binding of succinate by DBP was competitively inhibited by 10-fold concentrations of fumarate and malate but not by a variety of related substances. GBP synthesis and transport of methyl alpha-glucoside by whole cells were induced by growth on glucose or pyruvate plus galactose, 2-deoxyglucose, or methyl alpha-glucoside but not by growth on gluconate, succinate, acetate, or pyruvate. The binding of radioactive glucose by GBP was significantly inhibited by 10-fold concentrations of glucose, galactose, and glucose-1-phosphate but not by the other carbohydrates tested. The binding of glucose by GBP or succinate by DBP did not result in any chemical alteration of the substrates.  相似文献   

20.
Intracellular bacteria can reside in a vacuolar compartment, or they can escape the vacuole and become free living in the cytoplasm. The presentation of Ag by class I MHC molecules has been defined primarily for Ag present in the cytoplasm. It was therefore thought that Ags from bacteria that remain in a vacuole would not be presented by MHC class I molecules. Although some studies have provided data to support this idea, it is not necessarily true for all intracellular bacteria. For example, we have previously demonstrated that an epitope from the p60 protein secreted by LLO- Listeria monocytogenes, which does not reside in the cytoplasm, can be presented by MHC class I molecules to a T cell clone specific for the epitope, p60217-225. We have further examined the route by which Ag secreted by LLO- L. monocytogenes is presented by MHC class I molecules. Using pharmacological inhibitors, we demonstrate that MHC class I presentation of the p60 epitope derived from by LLO- L. monocytogenes requires phagolysosome fusion and processing by the proteasome. Lysosomal cathepsins, however, are not required for processing of the p60 epitope. Similarly, processing of the AttM epitope, secreted by LLO- L. monocytogenes and presented by H2-M3, also requires phagolysosome fusion and cleavage by the proteasome. Thus, p60 and AttM secreted by LLO- L. monocytogenes are processed via the classical class I pathway for presentation by MHC class I molecules.  相似文献   

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