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排序方式: 共有569条查询结果,搜索用时 31 毫秒
91.
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93.
Involvement of plasma membrane calcium influx in bacterial induction of the k/h and hypersensitive responses in tobacco 总被引:11,自引:7,他引:4
An early event in the hypersensitive response of tobacco to Pseudomonas syringae pv syringae is the initiation of a K+/H+ response characterized by specific plasma membrane K+ efflux, extracellular alkalinization, and intracellular acidification. We investigated the role of calcium in induction of these host responses. Suspension-cultured tobacco cells exhibited a baseline Ca2+ influx of 0.02 to 0.06 micromole per gram per hour as determined from 45Ca2+ uptake. Following bacterial inoculation, uptake rates began to increase coincidently with onset of the K+/H+ response. Rates increased steadily for 2 to 3 hours, reaching 0.5 to 1 micromole per gram per hour. This increased Ca2+ influx was prevented by EGTA and calcium channel blockers such as La3+, Co2+, and Cd2+ but not by verapamil and nifedipine. Lanthanum, cobalt, cadmium, and EGTA inhibited the K+/H+ response in both suspension-cultured cells and leaf discs and prevented hypersensitive cell death in leaf discs. We conclude that increased plasmalemma Ca2+ influx is required for the K+/H+ and hypersensitive responses in tobacco. 相似文献
94.
Enrico Casalone Carmine Di Ilio Giorgio Federici Mario Polsinelli 《Antonie van Leeuwenhoek》1988,54(4):367-375
Total glutathione content, glutathione peroxidase, glutathione transferase and glutathione reductase activities have been measured in 12 species of yeasts. All the strains tested contained glutathione, though in different amounts, as well as the above mentioned enzymes. To discriminate between the selenium-dependent and the selenium-independent form, glutathione peroxidase activity has been measured with both H2O2 and cumene hydroperoxide. Rhodotorula glutinis appeared to be the only strain in which the selenium-dependent form was not found, but this yeast exhibited the highest level of selenium-independent glutathione peroxidase activity as compared to the other strains. 相似文献
95.
Bonanni P. Caprioli R. Ghiara E. Mignuzzi C. Orlandi C. Paganin G. Monti A. 《Hydrobiologia》1992,235(1):553-568
The Orbetello lagoon is now highly eutrophic and has experienced increasing incidence of anoxia causing serious economic damage. A multidisciplinary study was commenced in March 1987 to investigate the part played by the lagoon sediments and interstitial water in recycling nutrients and contributing to the observed anoxia. Eleven undisturbed cores were collected and sub-sampled at 2 cm intervals. Interstitial water was obtained by centrifugation and analyzed for pH, Eh, nutrients, major and some minor elements. Differential fluxes from the sediments of 0.2–10 g cm–2 day–1 of ammonia and 0.02–0.7 g cm–2 day–1 of orthophosphate were obtained depending on the season, temperature of the sediments and the sampling location. A highly significant linear correlation (r
2 = 0.86) was found between bicarbonate and ammonia concentrations in the interstitial waters, due to the release of these compounds during the degradation organic matter. A diagenetic model was developed to predict the alkalinity of interstitial water from the theoretical reactions involved in the decomposition of organic matter. The predicted values for bicarbonate and ammonia agreed well with the experimental results. 相似文献
96.
Seveso Davide Montano Simone Maggioni Davide Pedretti Francesca Orlandi Ivan Galli Paolo Vai Marina 《Coral reefs (Online)》2018,37(3):801-806
Coral Reefs - In corals, different biological processes are associated with the daily variation of temperature and light, which in shallow reefs can vary widely and regularly reach extreme levels.... 相似文献
97.
David A. Schaer Richard P. Beckmann Jack A. Dempsey Lysiane Huber Amelie Forest Nelusha Amaladas Yanxia Li Ying Cindy Wang Erik R. Rasmussen Darin Chin Andrew Capen Carmine Carpenito Kirk A. Staschke Linda A. Chung Lacey M. Litchfield Farhana F. Merzoug Xueqian Gong Philip W. Iversen Michael Kalos 《Cell reports》2018,22(11):2978-2994
98.
Francesca Wanda Rossi Nella Prevete Felice Rivellese Antonio Lobasso Filomena Napolitano Francescopaolo Granata Carmine Selleri Amato de Paulis 《Clinical and molecular allergy : CMA》2016,14(1):15
Background
The Nef protein can be detected in plasma of HIV-1-infected patients and plays a role in the pathogenesis of HIV-1. Nef produced during the early stages of infection is fundamental in creating the ideal environment for viral replication, e.g. by reducing the ability of infected cells to induce an immune response.Aim
Based on previous experience showing that both Tat and gp41 of HIV-1 are potent chemotactic factors for basophils and mast cells, and gp120 is a powerful stimulus for the release of histamine and cytokines (IL-4 and IL-13) from basophils, in this study we aimed to verify if the HIV Nef protein can exert some effects on basophils and mast cells purified from healthy volunteers through the interaction with the CXCL12 receptor, CXCR4.Methods
Basophils purified from peripheral blood cells of 30 healthy volunteers and mast cells obtained from lung tissue of ten healthy volunteers were tested by flow cytometric analysis, chemotaxis and chemokine production by ELISA assays.Results
Nef is a potent chemoattractant for basophils and lung mast cells obtained from healthy, HIV-1 and HIV-2 seronegative individuals. Incubation of basophils and mast cells with Nef induces the release of chemokines (CXCL8/IL-8 and CCL3/MIP-1α). The chemotactic activity of Nef on basophils and mast cells is mediated by the interaction with CXCR4 receptors, being blocked by preincubation of FcεRI+ cells with an anti-CXCR4 Ab. Stimulation with Nef or CXCL12/SDF-1α, a CXCR4 ligand, desensitizes basophils to a subsequent challenge with an autologous or heterologous stimulus.Conclusions
These results indicate that Nef, a HIV-1-encoded α-chemokine homolog protein, plays a direct role in basophils and mast cell recruitment and activation at sites of HIV-1 replication, by promoting directional migration of human FcεRI+ cells and the release of chemokines from these cells. Together with our previous results, these data suggest that FcεRI+ cells contribute to the dysregulation of the immune system in HIV-1 infection.99.
M. Scimeca A. Pietroiusti F. Milano L. Anemona A. Orlandi L.T. Marsella E. Bonanno 《European journal of histochemistry : EJH》2016,60(1)
There is an increasing amount of evidence that nanoparticles may enhance toxicological potential in comparison to the same material in the bulk form. The aim of this study was to develop a new method to unmask asbestos nanofibers from Formalin-Fixed Paraffin-Embedded (FFPE) tissue. For the first time, in this study we applied Energy Dispersive X-ray (EDX) microanalysis through transmission electron microscopy to demonstrate the presence of asbestos nanofibers in histological specimens of patients with possible occupational exposure to asbestos. The diagnostic protocol was applied to 10 randomly selected lung cancer patients with no history of previous asbestos exposure. We detected asbestos nanofibers in close contact with lung cancer cells in two lung cancer patients with previous possible occupational exposure to asbestos. We were also able to identify the specific asbestos iso-type, which in one of the cases was the same rare variety used in the workplace of the affected patient. By contrast, asbestos nanofibers were not detected in lung cancer patients with no history of occupational asbestos exposure.The proposed technique can represent a potential useful tool for linking the disease to previous workplace exposure in uncertain cases. Furthermore, Formalin-Fixed Paraffin-Embedded (FFPE) tissues stored in the pathology departments might be re-evaluated for possible etiological attribution to asbestos in the case of plausible exposure. Since diseases acquired through occupational exposure to asbestos are generally covered by workers’ insurance in most countries, the application of the protocol used in this study may have also relevant social and economic implications.Key words: Asbestos fibers, nanofibers, EDX microanalysis, Transmission Electron Microscopy, lung cancer, occupational exposure 相似文献
100.
Graham R. Foster Carmine Coppola Moutaz Derbala Peter Ferenci Alessandra Orlandini K. Rajender Reddy Ludovico Tallarico Mitchell L. Shiffman Silke Ahlers Georgios Bakalos Tarek Hassanein GUARD-C Study Group 《PloS one》2016,11(3)