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91.
Jorge F. Perez-Quezada Macarena Moncada Patricio Barrales Rocío Urrutia-Jalabert Marco Pfeiffer Aldo Farías Herrera Rodrigo Sagardía 《Austral ecology》2023,48(5):893-903
We estimated the amount of carbon (C) stored in terrestrial ecosystems of the Chilean Patagonia and the proportion within protected areas. We used existing public databases that provide information on C stocks in biomass and soils. Data were analysed by ecosystem and forest type in the case of native forests. Our results show that some ecosystems have been more extensively studied both for their stocks in biomass and soils (e.g. forests) compared with others (e.g. shrublands). Forests and peatlands store the largest amount of C because of their large stocks per hectare and the large area they cover. The total amount of C stored per unit area varies from 261.7 to 432.8 Mg C ha−1, depending on the published value used for soil organic C stocks in peatlands, highlighting the need to have more precise estimates of the C stored in this and other ecosystems. The mean stock in national parks (508 Mg C ha−1) is almost twice the amount stored in undisturbed forests in the Amazon. State and private protected areas contain 58.9% and 2.1% of the C stock, respectively, playing a key role in protecting ecosystems in this once pristine area. 相似文献
92.
A. Martínez V. Riveros-Moreno J. M. Polak S. Moncada P. Sesma 《Cell and tissue research》1994,275(3):599-603
The neuroendocrine system of the starfish Marthasterias glacialis was investigated immunocytochemically using antisera specific for rat neuronal, bovine aortic endothelial, and mouse macrophage, nitric oxide (NO) synthases. Immunoreactivity was detected only with the antibodies specific for the neural enzyme, in the ectoneural and hyponeural tissues of the radial nerve cords and in the basiepithelial plexus and endocrine cells of the digestive tract. The pyloric stomach showed more immunoreactive structures than the other digestive organs, with the rectal caeca showing the least activity. Immunoreactive endocrine cells were located in the cardiac and pyloric stomachs and in the pyloric caeca. Co-localization of the enzyme immunoreactivity, and the staining for NADPH-diaphorase, demonstrate the presence of NO synthase in echinoderms. These results provide further evidence that NO is a neuronal messenger of early phylogenetic origin which has been conserved throughout evolution. 相似文献
93.
M. Lombroso S. Nicosia R. Paoletti B.J.R. Whittle S. Moncada J.R. Vane 《Prostaglandins & other lipid mediators》1984,27(2):321-333
Prostacyclin, (PGI2) is a potent but unstable inhibitor of platelet aggregation, probably acting through stimulation of adenylate cyclase.A stable analogue of prostacyclin with antiaggregatory properties, 5,6-dihydro-PGI2 (6β-PGI), and PGE1 can compete for the binding sites labelled by 3H-PGI2 in human platelet membranes (the affinity being PGI2 > PGE1 > 6β -PGI1). Both 6β-PGI1 and PGE1, as well as PGI2, bind to two classes of binding sites. 6β -PGI1 and PGE1 activate adenylate cyclase to the same extent as PGI2,with a rank order of potency which parallels that observed in binding experiments. The stimulation of this enzyme is brought about by interaction of each these prostanoids with two different classes of components. The comparison of binding and adenylate cyclase data suggests that the sites to which PGI2, 6β -PGI1 and PGE1 bind might be coupled to the activation of adenylate cyclase. Since 6β-PGI1 seems to act through the same molecular mechanisms as PGI2, because of its stability it is an useful tool to investigate the mode of action of prostacyclin in platelets. 相似文献
94.
The effects of prostacyclin (PGI2) and its breakdown product 6-oxo-PGF1alpha on various aspects of gastric function were investigated in the rat. PGI2 increased mucosal blood flow when infused intravenously. PGI2 was a more potent inhibitor of gastric acid secretion in vivo than PGE2. Like PGE2, PGI2 inhibited acid secretion from the rat stomach in vitro. PGI2 had comparable activity to PGE2 in inhibiting indomethacin-induced gastric erosions. Thus prostacyclin shares several of the activities of PGE2, and may be involved in the regulation of gastric mucosal function. 相似文献
95.
Prostacyclin (PGX) strikingly increases cyclic AMP concentrations in human platelets. Prostacyclin is approximately 10 times more active than PGD2, 30 times more active than PGE1 and more than 1000 times more active than its stable end product, 6-oxo-PGF1alpha. These results correlate well with the anti-aggregating activity of prostacyclin, compared with PGE1 and PGD2. 相似文献
96.
Infusions of prostacyclin (PGI2) (3 x 10(-10) - 3 x 10(-7)M) into the coronary circulation of isolated hearts from ginea pigs or rabbits resulted in a concentration-dependent decrease in the coronary perfusion pressure (CPP). There was a slight decrease in left ventricular systolic pressure in the heart of the rabbit, whereas the heart rate remained unchanged. PGE2 was without effect on the heart of the rabbit but was as potent as PGI2 in decreasing the CPP in the guinea pig heart. 6-oxo-PGF1 alpha (up to 3 x 10(-6) M) did not affect any of the parameters measured. 相似文献
97.
Prostacyclin generation by pericardium, pleura, peritoneum, aorta and dura mater of the rabbit was assessed as platelet aggregation inhibitory activity in platelet rich plasma. All tissues except the dura mater, were also incubated with labelled (1-14C) arachidonic acid and (1-14C) prostaglandin endoperoxide H2 and the various metabolites formed were identified radiochromatographically. Pericardium, pleura and peritoneum form substantially high amounts of prostacyclin and HETE indicating that these tissues contain both cyclo-oxygenase and prostacyclin-synthetase. They also show considerable lipoxygenase activity. 相似文献
98.
The effect of carbacyclin, a chemically stable analogue of prostacyclin (PGI2), on the adhesion of platelets to collagen has been examined. The compound was compared to PGI2 which is unstable and rapidly hydrolysed to the inactive derivative, 6-oxo-PGF 1 alpha. The adhesion of 111Indium-labelled human platelets to collagen in the absence of platelet aggregation and secretion was measured. The cAMP level in the platelets was also monitored. Both PGI2 and carbacyclin inhibited platelet-collagen adhesion and caused a rise in the platelet cAMP level. Carbacyclin was approximately 15-fold less effective than PGI2, however, its effect was longer lasting, remaining constant for at least 30 minutes. 相似文献
99.
Perez-Leal O Sierra AY Barrero CA Moncada C Martinez P Cortes J Lopez Y Salazar LM Hoebeke J Patarroyo MA 《Biochemical and biophysical research communications》2005,331(4):1178-1184
Plasmodium vivax malaria is one of the most prevalent parasitic diseases in Asia and Latin-America. The difficulty of maintaining this parasite culture in vitro has hampered identifying and characterising proteins implied in merozoite invasion of red blood cells. We have been able to identify an open reading frame in P. vivax encoding the Plasmodium falciparum merozoite surface protein 10 homologous protein using the partial sequences from this parasite's genome reported during 2004. This new protein contains 479 amino-acids, two epidermal growth factor-like domains, hydrophobic regions at the N- and C-termini, being compatible with a signal peptide and a glycosylphosphatidylinositol anchor site, respectively. The protein is expressed during the parasite's asexual stage and is recognised by polyclonal sera in parasite lysate using Western blot. P. vivax-infected patients' sera highly recognised recombinant protein by ELISA. 相似文献
100.
Schierloh P Yokobori N Alemán M Musella RM Beigier-Bompadre M Saab MA Alves L Abbate E de la Barrera SS Sasiain MC 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(10):6852-6860
Tuberculous pleuritis is a good model for the study of specific cells at the site of active Mycobacterium tuberculosis (Mtb) infection. We investigated the frequency and phenotype of NK cells in paired samples of peripheral blood and pleural fluid (PF) from patients with tuberculosis (TB) or parapneumonic infection. We demonstrated for the first time a reduction of NK cells in PF from TB with an enrichment in the CD56brightCD16- subset. In agreement, in PF NK cells we observed an increased expression of CD94, NKG2A, CD62L, and CCR7 molecules and lower expression of Bcl-2 and perforin. The activation markers CD69 and HLA-DR were also increased. The enrichment in the CD56bright subset was due to an increased susceptibility to apoptosis of CD56+CD16+ NK cells mediated by heat-labile and stable soluble factors present in tuberculous effusions and not in PF from other etiologies. Furthermore, in TB patients, Mtb-induced IFN-gamma production by PF NK cells was not dependent on the presence of CD3+, CD19+, and CD14+ cells, suggesting a direct interaction of CD56bright cells with Mtb and/or the involvement of other accessory cells present at the site of Mtb infection. 相似文献