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排序方式: 共有801条查询结果,搜索用时 15 毫秒
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H. Elenga O. Peyron R. Bonnefille D. Jolly R. Cheddadi J. Guiot V. Andrieu S. Bottema G. Buchet J.-L. De Beaulieu A. C. Hamilton J. Maley R. Marchant R. Perez-Obiol M. Reille G. Riollet L. Scott H. Straka D. Taylor E. Van Campo A. Vincens F. Laarif H. Jonson 《Journal of Biogeography》2000,27(3):621-634
Pollen data from 18,000 14C yr bp were compiled in order to reconstruct biome distributions at the last glacial maximum in southern Europe and Africa. Biome reconstructions were made using the objective biomization method applied to pollen counts using a complete list of dryland taxa wherever possible. Consistent and major differences from present‐day biomes are shown. Forest and xerophytic woods/scrub were replaced by steppe, both in the Mediterranean region and in southern Africa, except in south‐western Cape Province where fynbos (xerophytic scrub) persisted. Sites in the tropical highlands, characterized today by evergreen forest, were dominated by steppe and/or xerophytic vegetation (cf. today’s Ericaceous belt and Afroalpine grassland) at the last glacial maximum. Available data from the tropical lowlands are sparse but suggest that the modern tropical rain forest was largely replaced by tropical seasonal forest while the modern seasonal or dry forests were encroached on by savanna or steppe. Montane forest elements descended to lower elevations than today. 相似文献
3.
Carboxypeptidase N (kininase I) activity in blood and synovial fluid from patients with arthritis 总被引:3,自引:0,他引:3
Carboxypeptidase N (CPN, kininase I) and kininase II (angiotensin converting enzyme) activities were measured simultaneously in blood plasma and synovial fluid in patients suffering from rheumatoid arthritis (RA), psoriatic arthritis (PA) and osteoarthritis (OA) and in the plasma of normal volunteers. CPN levels (defined as the rate of hydrolysis of furylacryloyl-Ala-Lys) in blood were modestly increased and correlated with erythrocyte sedimentation rate in RA and PA. Based on the hydrolysis of synthetic substrates, CPN activity was much higher than kininase II activity in synovial fluid (SF). SF kininase activities were always inferior to the blood levels in all patients and were correlated with the logarithm of SF leukocyte counts, an indicator of the intensity of inflammation. In addition, CPN and albumin levels in SF were highly correlated when expressed as a percent of the plasma concentrations. Biochemical properties of CPN in crude SF confirmed its similarity to blood CPN. Polymorphonuclear leukocytes derived from inflammatory SF did not release CPN. It is concluded that kininases diffuse from the blood into SF through increased vascular permeability and that CPN could be a major metabolic pathway for kinins in this form of exudate. CPN leads to the formation of des-Arg kinins, selective agonists of the B1 receptors for kinins. 相似文献
4.
Marie-Claude Pepin Serge Beaulieu Nicholas Barden 《Cellular and molecular neurobiology》1990,10(2):227-235
1. Differential regulation, by dexamethasone, of glucocorticoid receptor gene expression was studied in three different neuronal cultures derived from hypothalamus amygdala, and cerebral cortex. 2. Cellular glucocorticoid receptor (GR) mRNA concentration was measured by hybridization using a 32P-labeled RNA probe complementary to a 2.2-kb fragment of the glucocorticoid receptor mRNA. Changes in the amount of GR mRNA were evaluated in relation to the content of beta-actin mRNA. 3. In cells derived from either hypothalamus or cerebral cortex, we observed a complex pattern of GR mRNA concentrations which were characterized by cyclic variations of GR mRNA content during continuous treatment with dexamethasone for up to 72 hr. 4. In contrast to cells derived from the hypothalamus where a persistent 30-40% reduction in GR mRNA levels was seen for up to a least 72 hr, we observed, in cells derived from the cerebral cortex, a sustained increased (1.4-fold) of the GR mRNA at this same time interval. 相似文献
5.
Salas-Prato Milagros Tanguay Jean-Francois Lefebvre Yves Wojciechowicz Don Liem H. Heng Barnes David W. Ouellette Ginette Muller-Eberhard Ursula 《In vitro cellular & developmental biology. Plant》1988,24(5):470-470
In Vitro Cellular &; Developmental Biology - Plant - 相似文献
6.
The authors describe the presentation, clinical evaluation and treatment of 151 patients (mean age 36.3 years) who presented to an outpatient clinic or the emergency department between Oct. 29, 1984, and Apr. 15, 1985, for a lateral ankle sprain. About 60% of the sprains were considered minor. Although 141 patients underwent simple radiography of the ankle on the first visit, only five fractures were identified. All the fractures were uncomplicated and were treated conservatively. No common criteria could be identified to explain why some patients with sprains of moderate severity were referred to an orthopedist while others were not. Of the 53 patients interviewed, 22 still had some limitation of physical activity 6 weeks after the sprain. The presence of malleolar soft-tissue swelling, pain in the bony structures and inability to bear weight should raise the suspicion of a fracture. If radiography had been limited to patients with these signs, no fracture would have been missed, and radiography would have been avoided in 70 cases. 相似文献
7.
The effects of deregulation of NR gene expression on growth and nitrogen metabolism of Nicotiana plumbaginifolia plants 总被引:1,自引:0,他引:1
8.
Stanislas Tomavo Jean-Francois Dubremetz Ralph T. Schwarz 《Biology of the cell / under the auspices of the European Cell Biology Organization》1993,78(3):155-162
In this study we describe the biochemical features of the Toxoplasma gondii tachyzoite surface glycoprotein, gp23, demonstrating that it is attached to the parasite membrane by a glycosyl-phosphatidyl inositol anchor. Gp23 was metabolically labeled with tritiated palmitate, myristate, ethanolamine, inositol, glucosamine, mannose and galactose, as expected for a GPI-anchor structure. Gp23 was released from the surface of living parasites after treatment with phosphatidyl inositol-specific phospholipase C (PI-PLC) and the resulting water-soluble protein was immunoprecipitated with a monoclonal antibody specific for gp23. The GPIcore glycan was generated after aqueous-HF dephosphorylation followed by nitrous acid deamination and its carbohydrate structure was analyzed using selective exo- and endoglycosidase treatments. Finally, the phosphatidylinositol moiety of gp23 was characterized using PI-PLC and phospholipase A2 (PLA2) digestions. Our cumulative data suggest that gp23 of T gondii tachyzoites contains a modified GPI-backbone similar to the mammalian Thy-1 anchor, consisting of a conserved core structure (ethanolaminePO4-6-Manαl-2-Manαl-6-Manαl-4-GIcNαl-6-PI) bearing β-linked N-acetylgalactosamine residue(s). 相似文献
9.
The Pr60gag protein of the murine AIDS (MAIDS) defective virus promotes the proliferation of the infected target B cells and is responsible for inducing a severe immunodeficiency disease. Using the yeast two-hybrid system, we identified the SH3 domain of c-Abl as interacting with the proline-rich p12 domain of Pr60gag. The two proteins were shown to associate in vitro and in vivo in MAIDS virus-infected B cells. Overexpression of Pr60(gag) in these cells led to a detectable increase of the levels of c-Abl protein and to its translocation at the membrane. These results suggest that this viral protein serves as a docking site for signaling molecules and that c-Abl may be involved in the proliferation of infected B cells. 相似文献
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