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排序方式: 共有164条查询结果,搜索用时 16 毫秒
1.
Carlo Ferrarese Flora Vaccarino Hannu Alho Britt Mellstrom Erminio Costa Alessandro Guidotti 《Journal of neurochemistry》1987,48(4):1093-1102
Diazepam binding inhibitor (DBI), a peptide located in CNS neurons, blocks the binding of benzodiazepines and beta-carbolines to the allosteric modulatory sites of gamma-aminobutyric acid (GABAA) receptors. Subcellular fractionation studies of rat brain indicate that DBI is compartmentalized. DBI-like immunoreactivity is highly enriched in synaptosomes obtained by differential centrifugation in isotonic sucrose followed by a Percoll gradient. In synaptosomal lysate, DBI-like immunoreactivity is primarily associated with synaptic vesicles partially purified by differential centrifugation and continuous sucrose gradient. Depolarization induced by high K+ levels (50 mM) or veratridine (50 microM) released DBI stored in neurons of superfused slices of hypothalamus, hippocampus, striatum, and cerebral cortex. The high K+ level-induced release is Ca2+ dependent, and the release induced by veratridine is blocked by 1.7 microM tetrodotoxin. Depolarization released GABA and Met5-enkephalin-Arg6-Phe7 together with DBI. DBI is also released by veratridine depolarization, in a tetrodotoxin-sensitive fashion, from primary cultures of cerebral cortical neurons, but not from cortical astrocytes. Depolarization fails to release DBI from slices of liver and other peripheral organs. These data support the view that DBI may be released as a putative neuromodulatory substance from rat brain neurons. 相似文献
2.
Piero Pollesello Renato Toffanin Erminio Murano Roberto Rizzo Sergio Paoletti Bjarne J. Kvam 《Journal of applied phycology》1992,4(2):149-155
Lipid extracts of the red algaGracilaria longa were studied by1H- and13C-NMR spectroscopy. Peaks in the13C-NMR spectra attributable to sterols, chlorophylls and carotenoids allowed free and acylated cholesterol, chlorophylla and lutein to be identified as the most abundant components of these classes. A content of 0.5 ± 0.1 μmoles of total cholesterol/g
wet alga was estimated from the1H-NMR spectrum, which also allowed the determination of the phosphatidylcholine/total lipid molar ratio (9.5 ± 0.5%). The13C-NMR spectroscopic experiments provided information on the position of the double bonds on the fatty acid residues. A comparison
between NMR spectra of lipid extracts obtained for wet and dried alga showed that the alga undergoes both a dramatic peroxidation
and some glycolipid degradation during the drying process. 相似文献
3.
Modulation of the urokinase receptor in human colon cell lines by N,N-dimethylformamide 总被引:1,自引:0,他引:1
The present study documents the effect of the planar, polar differentiation promoter N,N-dimethylformamide (DMF) on urokinase binding to colon carcinoma cells. Exposure of the colon carcinoma cell lines to the agent resulted in enhanced specific binding of radioactive urokinase to all cells tested. Insulin binding to the cells was, however, unaffected by DMF. A DMF exposure period of 45 h was required to observe maximum urokinase binding to two representative cell lines FET and RKO. Optimal stimulation of both cell lines occurred with 0.8% DMF. Scatchard analysis revealed the dissociation constants to be unchanged by the agent with the increased binding of radioactive plasminogen activator reflecting an up-regulation of binding sites. In this regard, the cell line RKO upon exposure to DMF, displayed approx. 700,000 receptors/cell, the highest value published, to date, for any cell line. 相似文献
4.
Maria C. Olianas Pierluigi Onali Norton H. Neff Erminio Costa 《Journal of neurochemistry》1983,41(5):1364-1369
We investigated the effect of acetylcholine (ACh) on the activation of adenylate cyclase by dopamine (DA) in a lysed synaptosomal preparation from rat striatum. ACh reduced both basal and the DA-activated adenylate cyclase with an apparent IC50 of approximately 1 microM. From a kinetic analysis it appeared that ACh reduced the Vmax for activation by DA but not the activation constant for DA. For most preparations the Vmax was reduced by 30-40%. The presence of atropine did not affect the activation of the enzyme by DA but it blocked the inhibition by ACh. Following 6-hydroxydopamine lesion of the nigrostriatal pathway, the enzyme became supersensitive to activation by DA and also more sensitive to inhibition by ACh. Inhibition of adenylate cyclase by ACh appeared to be rather specific for activation by DA, as ACh had no effect on activation of adenylate cyclase by the adenosine analogue N6-(L-2-phenylisopropyl)adenosine. These results indicate that some striatal muscarinic and dopaminergic receptors are probably coupled to the same adenylate cyclase domain. Moreover, they suggest a biochemical model for the dynamic balance of cholinergic and dopaminergic neurons that innervate the striatum. 相似文献
5.
Endogenous Benzodiazepine Receptor Ligands in Human and Animal Hepatic Encephalopathy 总被引:6,自引:1,他引:5
Marjut Olasmaa Jeffrey D. Rothstein Alessandro Guidotti Richard J. Weber† Steven M. Paul‡ Sydney Spector§ Maria L. Zeneroli Mario Baraldi Erminio Costa 《Journal of neurochemistry》1990,55(6):2015-2023
The role of endogenous benzodiazepine receptor ligands in the pathogenesis of hepatic encephalopathy was studied in humans and in rat models of hepatic encephalopathy. Endogenous benzodiazepine ligands were extracted from rat brain and human CSF by acid treatment and purification by HPLC. Detection and partial characterization of these endogenous benzodiazepine ligands were carried out using both radioreceptor binding assays and radioimmunoassays with anti-benzodiazepine antibodies. Four different benzodiazepine receptor ligands were identified in human and rat tissue, two of which may be diazepam and desmethyldiazepam, based on elution profiles and anti-benzo-diazepine antibody reactivity. Human CSF and serum from patients with hepatic encephalopathy contained approximately 10 times more endogenous benzodiazepine receptor ligand than CSF from controls or nonencephalopathic patients with liver disease. The levels of brain benzodiazepine receptor ligand compounds were also increased approximately 10-fold in rats suffering from fulminant hepatic failure, but not in rats with portacaval shunts, a model of chronic hepatic disease. The increased concentrations of these substances could be behaviorally significant and may contribute to the pathogenesis of hepatic encephalopathy. 相似文献
6.
7.
Evidence for Ascending and Descending Intraspinal as Well as Primary Sensory Somatostatin Projections in the Rat Spinal Cord 总被引:2,自引:1,他引:1
Somatostatin distribution was measured quantitatively in the rat spinal cord by radioimmunoassay. Rostro-caudally, somatostatin content was about 50% higher in lumbar-sacral cord than in cervical or thoracic levels. The dorso-ventral distribution is more uneven: somatostatin is highest in the dorsal horn, where the peptide is 15 times as concentrated as it is in the ventral white matter, the region of lowest concentration. However, measurable amounts of the peptide were found in all regions studied. Dorsal root ganglionectomy decreased somatostatin levels in the dorsal cord, supporting the previously proposed role for this peptide as a primary sensory neurotransmitter or modulator; but somatostatin content also was decreased both rostral and caudal to spinal transection, indicating the presence of ascending and descending somatostatin pathways within the spinal cord. Brain levels did not change. Met-enkephalin and substance P were also measured after the above surgical manipulations. Met-enkephalin content was not altered and substance P content was lowered significantly only after ganglionectomy. Although this study confirms the primary sensory neuron as the origin of a part of spinal cord somatostatin, it further indicates the presence of ascending and descending somatostatin pathways within the rat spinal cord. 相似文献
8.
Liver plasma membranes were isolated from regenerating rat livers between 20 h and 10 days after partial hepatectomy in order to study the effect of partial hepatectomy on some membrane enzyme activities. Mg2+-ATPase (EC 3.6.1.4) activity, but not (Na+ + K+)-ATPase activity, decreased slightly at 2 days, whereas leucyl beta-naphthylamidase (EC3.4.1.1) and 5'-nucleotidase (EC3.1.3.5) activities increased considerably at 1-2 and 3-5 days, respectively. These changes were not parallel to a sharp increase in mitotic activity of liver cells which occurred at 36 h. 相似文献
9.
Toshiharu Takahashi Tomoya Murano 《Bioscience, biotechnology, and biochemistry》2013,77(11):1922-1930
ABSTRACTRice blast caused by Pyricularia oryzae (syn. Magnaporthe oryzae) is a disease devastating to rice. We have studied the Arabidopsis-P. oryzae pathosystem as a model system for nonhost resistance (NHR) and found that SOBIR1, but not BAK1, is a positive regulator of NHR to P. oryzae in Arabidopsis. AGB1 is also involved in NHR. However, the genetic interactions between SOBIR1, BAK1, and AGB1 are uncharacterized. In this study, we delineated the genetic interactions between SOBIR1, BAK1, and AGB1 in NHR to P. oryzae in Arabidopsis and found SOBIR1 and AGB1 independently control NHR to P. oryzae in Arabidopsis pen2-1 mutant plants. Furthermore, XLG2, but not TMM, has a positive role in penetration resistance to P. oryzae in Arabidopsis pen2-1 mutant plants. Our study characterized genetic interactions in Arabidopsis NHR.Abbreviations: PRR: pattern recognition receptor, RLK: receptor-like kinase, RLP: receptor-like protein, BAK1: BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1, BIR1: BAK1-INTERACTING RECEPTOR-LIKE KINASE 1, SOBIR1: SUPPRESSOR OF BIR1-1-1, AGB1: ARABIDOPSIS G PROTEIN ß-SUBUNIT 1, XLG2: EXTRA-LARGE G PROTEIN 2 相似文献
10.
Erminio Ferrarini 《Plant biosystems》2013,147(2):55-87
Abstract The vegetation of the Palmaria and Tino Islands (Gulf of La Spezia). — The vegetation of the Palmaria and Tino islands in the Gulf of La Spezia shows various aspects although they are completely calcareous and do not exceed two hundred meters in height. Along the coast, we have noticed some small beaches with a few psammophytes, and some cliffs vertically overlooking the sea with the endemic Centaurea cineraria var. veneris and with a few shrubs (among which I would like to mention Pinus halepensis) that become bigger and bigger and grow in number with the altitude. On the southern side of Palmaria the Mediterranean « maquis » with Calicotome spinosa, Cistus monspeliensis, Myrtus communis and Pistacia lentiscus is to be noticed. This bush is either compact or rarefied so that it makes a sort of « garigue » on limestone with Euphorbia dendroides, Helichrysum stoechas, Ruta chalepensis, Thymus vulgaris. Owing to the fact that some land strips of Palmaria escaped from fire a thermophilous vegetation is to be found, with a few trees of Pinus halepensis and with a thick undergrowth of Euphorbia dendroides, Cistus incanus, Pistacia lentiscus, Myrtus communis, Smilax aspera. The vegetation of the northern side of Palmaria and Tino is less thermophilous, together with a thick wood of Quercus ilex with some plants of Quercus pubescens and with undergrowth of Viburnum tinus, Smilax aspera, Smilax mauritanica, Coronilla emerus; this wood, especially in the higher part of Palmaria, shows some glades where Erica arborea, Cistus salvifolius, Dorycnium hirsutum grow, with some entities which are distributed quite far from the sea, such as Peucedanum cervaria. Still on the northern side of Palmaria there are some traces of chestnut woods with Castanea sativa, Quercus pubescens, Ostrya carpinifolia, Corylus avellana, Cytisus laburnum and with some plants that usually grow in the cooler areas among the chestnut woods and often in the beech woods like Daphne laureola, Digitalis lutea, Helleborus foetidus and Sesleria autumnalis. A comparison between the biological spectrum of the two islands with the one of Capo Caccia in north western Sardinia and of Marettimo island in western Sicily, clearly shows that in going down southwards, a strong increase of the therophytes (respectively 29,57%, 41,73%, 49,59%), of the chamaephytes and of the nanophanerophytes (13,53%, 16,94%, 18,47%) is to be noticed, while the hemicryptophytes decrease (35,33%, 22,72%, 21,28%). Besides, the vegetation of Capo Caccia although being situated half way between the two Ligurian islands and Marettimo, is much more similar to the latter one; evidently Palmaria and Tino are conditioned by their closeness to the La Spezia coasts while having a climate quite different from them. 相似文献