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131.
V. Molitor M. Trnka W. Erber I. Steffan M. -E. Rivière B. Arrio H. Springer-Lederer G. A. Peschek 《Archives of microbiology》1990,154(2):112-119
During adaptation of photoautotrophically growing fresh water cyanobacterium Anacystis nidulans to high salinity the cells showed a pronounced increase of proton-sodium antiporter activity, and of cytochrome c oxidase in isolated and purified plasma membrane. At the same time the concentrations of plasma membrane-bound EDTA-resistant copper and iron (determined by inductively coupled plasma atomic emission spectrometry) rose proportionately, accompanied by an increase in whole cell respiration. In plasma membranes from salt adapted cells lipid/protein ratios were markedly higher than in control cells, levels of esterified saturated and long-chain fatty acids being significantly higher than the respective levels of unsaturated and short-chain fatty acids which explains the higher lipid-phase transition temperatures derived from Arrhenius plots. Immunoblotting of the membrane proteins with antisera raised against the cytochrome c oxidases from Paracoccus denitrificans and A. nidulans gave two cross-reacting bands with apparent molecular weights around 50000 and 30000 (subunits I and II, respectively) which were more pronounced in plasma membranes from salt adapted cells when compared to control cells. The protein pattern of plasma membranes from salt adapted cells also showed the appearance of bands at apparent molecular weights of 44000–48000 and 54000–56000 which might stem from the proton/sodium-antiporter in this membrane.Abbreviations CM
cytoplasmic or plasma membrane
- ICM
intracytoplasmic or thylakoid membrane
- cyt
cytochrome
- DCCD
N,N-dicyclohexylcarbodiimide
- Hepes
N-2-hydroxyethylpiperazine-N-2-ethanesulfonate
- ICP-AES
inductively coupled plasma atomic emission spectrometry
- SDS-PAGE
sodium dodecylsulfate polyacrylamide gel electrophoresis
- EPR
electron paramagnetic resonance spectrometry 相似文献
132.
Anna L. Ballard Alastair G. McEwan David J. Richardson J. Baz Jackson Stuart J. Ferguson 《Archives of microbiology》1990,154(3):301-303
Rhodobacter capsulatus strain BK5 possesses a membrane bound respiratory nitrate reductase rather than the periplasmic enzyme found in other strains. The enzyme in strain BK5 is shown to be both functionally and structurally related to the nitrate reductase of Paracoccus denitrificans and Escherichia coli.Abbreviation TMAO
trimethylamine-N-oxide 相似文献
133.
Synaptosomal membrane proteins solubilized with 8% CHAPS-8 M urea were analyzed with twodimensional electrophoresis (2DE). The membrane proteins were resolved up to 250 spots on a 2DE map, ranging in isoelectric points (pI) from 3.5 to 10.0 and molecular weights (MW) from 10 kDa to 200 kDa. Comparison of the mapped proteins of synaptosomal membranes with those of myelin and mitochondorial membranes revealed that synaptosomal membrane proteins were characteristic in the area of pI from 4.0 to 7.5 and MW from 20 kDa to 130 kDa, and that at least 30 spots were synaptosomal membrane-specific proteins. Most of these 30 proteins have not been previously described, named, and characterized Serial numbers (from SY1 to SY30) were assigned to the proteins on the map in order to investigate them systematically. A preliminary attempt to separate synaptosomal membrane proteins was carried out using a reversed-phase HPLC system. Several proteins could either be isolated or enriched. SY10 (pI 4.6; MW 56 kDa) was one of these proteins, and was of particular interest for its unusual behavior on the reversed-phase column, and for its binding to an immobilized protein A-gel. 相似文献
134.
C. Bandeira-Duarte C. A. M. Carvalho E. J. Cragoe Jr A. P. Carvalho 《Neurochemical research》1990,15(3):313-320
Preparations of synaptosomes isolated in sucrose or in Na+-rich media were compared with respect to internal pH (pH1), internal Ca2+ concentration ([Ca2+]i), membrane potential and45Ca2+ uptake due to K+ depolarization and Na+/Ca2+ exchange. We found that synaptosomes isolated in sucrose media have a pHi of 6.77±0.04 and a [Ca2+]i of about 260 nM, whereas synaptosomes isolated in Na+-rich ionic media have a pHi of 6.96±0.07 and a [Ca2+]i of 463 nM, but both types of preparations have similar membrane potentials of about –50 mV when placed in choline media. The sucrose preparation takes up Ca2+ only by voltage sensitive calcium channels (VSCC'S) when K+-depolarized, while the Na+-rich synaptosomes take up45Ca2+ both by VSCC'S and by Na+/Ca2+ exchange. The amiloride derivative 2, 4 dimethylbenzamil (DMB), at 30 M, inhibits both mechanisms of Ca2+ influx, but 5-(N-4-chlorobenzyl)-2, 4 dimethylbenzamil (CBZ-DMB), at 30 M, inhibits the Ca2+ uptake by VSCC'S, but not by Na+/Ca2+ exchange. Thus, DMB and CBZ-DMB permit distinguishing between Ca2+ flux through channels and through Na+/Ca2+ exchange. We point out that the different properties of the two types of synaptosomes studied account for some of the discrepancies in results reported in the literature for studies of Ca2+ fluxes and neurotransmitter release by different types of preparations of synaptosomes.Abbreviations used BCECF
2,7-Biscarboxyethyl-5(6)-carboxyfluorescein
- BCECF/AM
acetoxymethyl ester of BCECF
- [Ca2+]i
Internal free calcium ion concentration
- CBZ-DMB
5-(N-4-chlorobenzyl)-2,4-dimethylbenzamil
- DMB
2, 4-dimethylbenzamil
- DMSO
dimethyl sulfoxide
- Indo-1/AM
acetoxymethyl ester of Indo-1
- MES
2-|N-Morpholino|ethanesulfonic acid
- NMG
N-methyl-D-glucamine
- pHi
internal pH
- TPP+
tetraphenylphosphonium
- p
plasma membrane potential 相似文献
135.
消炎痛对大鼠肝线粒体微粒体^45Ca摄取及膜流动性的影响 总被引:2,自引:0,他引:2
我们曾报道消炎痛预处理在大鼠能引起明显的肝保护作用,为了进一步探讨消炎痛肝保护作用的机制,本工作观察了它对大鼠肝线粒体、微粒体钙调节作用及膜流动性的影响。结果表明,经消炎痛整体预处理的大鼠肝线粒体和微粒体的钙摄取及膜流动性均明显增加,但是,将消炎痛直接加入由正常大鼠分离的线粒体或微粒体中,则反而使膜的流动性降低。这些变化可能与消炎痛的肝保护作用有关。 相似文献
136.
137.
用计算机处理脑片诱发电位可大大提高数据处理效率和信息提取率,并使大量、连续观察成为可能,本系统数据采集板与计算机之间采用DMA方式进行数据传送,包括采样子程序在内的全部处理程序均用高级BASIC语言编写,文中介绍了该程序各项功能和有关编程技巧以及海马脑片实验中的应用实例。 相似文献
138.
麦田冠层气孔导度的分层研究 总被引:2,自引:0,他引:2
小麦灌浆期和乳熟期冠层各层叶片上、下表面的气孔导度之间呈正相关关系;冠层不同层的叶片气孔导度从早到傍晚有平行变化的趋势,数值上存在较大的差异,一般从冠层上到下递减。经分析,这主要与冠层叶片接受的光强自上而下递减有关,且这时所对应的叶片水势自冠层上到下递增的幅度大。测算结果表明,冠层气孔导度白天亦呈明显的日变化,灌浆期的值大于乳熟期的值。 相似文献
139.
Jaime Cavelier 《Trees - Structure and Function》1990,4(3):155-163
Summary Diurnal courses of stomatal conductance, leaf water potential, and the components of tissue water potential were measured in six canopy species in an elfin cloud forest. High values of stomatal conductance were measured on cloudy days and during early morning and late afternoon of sunny days. Decreases in stomatal conductance with increases in vapour pressure deficit may have been a response to avoid further water deficits and suggested a stomatal response to changes in relative humidity. Daily transpiration varied between 470 and 1014 g m-2 day-1 during cloudy days and between 532 and 944 g m-2 day-1 during clear days. Stomatal conductance may have also responded to changes in leaf water potential, which was minimum at noon. The minimum tissue water potential measured in the field was -1.8 MPa in Myrcianthes fragrans, and the minimum turgor pressure was 0.49 MPa also in M. fragrans. There was a correlation between the osmotic potential and the minimum tissue water potential, suggesting that osmotic potential plays a major role in the maintenance of turgor in these species, in spite of the great variability in the elastic properties of leaf tissues. Turgor pressure decreased during the day following the course of water potential but never approached the turgor loss point, as it has been measured in some lowland rain forest trees. This is a strong indication that elfin cloud forest trees do not suffer severe water deficits, and that small tree stature is not directly related to water shortage. 相似文献
140.
Summary We raised monoclonal antibodies against a membrane fraction ofXenopus neurulae in order to detect tissue-specific cell-surface markers. Here we describe a monoclonal antibody that recognizes an epithelial membrane-associated antigen (EMA) in immunohistological stainings. The tissue-specific and membrane-associated antigen detected in immunohistological stainings could serve as useful marker in epithelium differentiation and membrane organization of the early embryo. In tadpoles and adults EMA was found in specific epithelial tissues derived from different germ layers such as kidney, skin, gut, pancreas, epiphysis and choroid plexus. In the cleaving embryo this antibody stained newly formed membranes between blastomeres from the two-cell stage onwards. Cytoplasmic staining in large oocytes and early embryos was also observed. The possibility that the cytoplasmic signal represents a maternal store of membrane material is discussed. 相似文献