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831.
Bosch M Marí M Herms A Fernández A Fajardo A Kassan A Giralt A Colell A Balgoma D Barbero E González-Moreno E Matias N Tebar F Balsinde J Camps M Enrich C Gross SP García-Ruiz C Pérez-Navarro E Fernández-Checa JC Pol A 《Current biology : CB》2011,21(8):681-686
Caveolins (CAVs) are essential components of caveolae, plasma membrane invaginations with reduced fluidity, reflecting cholesterol accumulation. CAV proteins bind cholesterol, and CAV's ability to move between cellular compartments helps control intracellular cholesterol fluxes. In humans, CAV1 mutations result in lipodystrophy, cell transformation, and cancer. CAV1 gene-disrupted mice exhibit cardiovascular diseases, diabetes, cancer, atherosclerosis, and pulmonary fibrosis. The mechanism or mechanisms underlying these disparate effects are unknown, but our past work suggested that CAV1 deficiency might alter metabolism: CAV1(-/-) mice exhibit impaired liver regeneration unless supplemented with glucose, suggesting systemic inefficiencies requiring additional metabolic intermediates. Establishing a functional link between CAV1 and metabolism would provide a unifying theme to explain these myriad pathologies. Here we demonstrate that impaired proliferation and low survival with glucose restriction is a shortcoming of CAV1-deficient cells caused by impaired mitochondrial function. Without CAV1, free cholesterol accumulates in mitochondrial membranes, increasing membrane condensation and reducing efficiency of the respiratory chain and intrinsic antioxidant defense. Upon activation of oxidative phosphorylation, this promotes accumulation of reactive oxygen species, resulting in cell death. We confirm that this mitochondrial dysfunction predisposes CAV1-deficient animals to mitochondrial-related diseases such as steatohepatitis and neurodegeneration. 相似文献
832.
833.
Wu J Ekman C Jönsen A Sturfelt G Bengtsson AA Gottsäter A Lindblad B Lindqvist E Saxne T Dahlbäck B 《Arthritis research & therapy》2011,13(2):R62
Introduction
Mer and Tyro3 are receptor tyrosine kinases important for the phagocytosis of apoptotic cells. Together with Axl, they constitute the TAM receptor family. These receptors can be shed from the cell membrane and their soluble extracellular regions can be found in plasma. The objective of this study was to elucidate whether the plasma levels of soluble Mer (sMer) and Tyro3 (sTyro3) were increased in systemic lupus erythematosis (SLE), rheumatoid arthritis (RA), or critical limb ischemia (CLI). 相似文献834.
835.
Elisabet V. Wehncke Mario S. Di Bitetti 《Studies on Neotropical Fauna and Environment》2013,48(2):142-146
Capuchin monkeys (Cebus nigritus) in Argentina prefer particular sleeping trees they maintain over the years. We compared species composition and abundance of seedlings under these sites with that of control sites. Species richness and abundance of seedlings was higher under sleeping trees than in control plots. Moreover, the proportion of dispersed versus non-dispersed species and individuals by capuchins was higher under the most frequently used sleeping trees than in control plots located in other areas of their home range. Thus, the dominance of plant species dispersed by these primates in the seedling assemblages below sleeping trees confirm the strong weight of C. nigritus and their potential influence in the dynamics of the seedling populations in the forest.Los monos capuchinos (Cebus nigritus) en Argentina prefieren árboles dormideros particulares que mantienen durante varios años. Comparamos la composición y la abundancia de especies de plántulas debajo de estos sitios con la de sitios controles. La riqueza y abundancia de especies de plántulas fue mayor debajo de árboles dormideros que en parcelas controles. Además la proporción de especies e individuos dispersados vs. no dispersados por los capuchinos fue mayor debajo de los árboles dormideros más frecuentemente usados que en parcelas controles ubicadas en otras partes de su área de acción. Así la dominancia de las especies de plantas dispersadas por estos primates en los ensambles de plántulas debajo de los árboles dormideros confirma el fuerte peso de C. nigritus y su influencia potencial en las dinámicas de las poblaciones de plántulas en el bosque. 相似文献
836.
Iridium oxide pH sensor for biomedical applications. Case urea-urease in real urine samples 总被引:1,自引:0,他引:1
E Prats-Alfonso L Abad N Casañ-Pastor J Gonzalo-Ruiz E Baldrich 《Biosensors & bioelectronics》2013,39(1):163-169
This work demonstrates the implementation of iridium oxide films (IROF) grown on silicon-based thin-film platinum microelectrodes, their utilization as a pH sensor, and their successful formatting into a urea pH sensor. In this context, Pt electrodes were fabricated on Silicon by using standard photolithography and lift-off procedures and IROF thin films were growth by a dynamic oxidation electrodeposition method (AEIROF). The AEIROF pH sensor reported showed a super-Nerstian (72.9±0.9mV/pH) response between pH 3 and 11, with residual standard deviation of both repeatability and reproducibility below 5%, and resolution of 0.03 pH units. For their application as urea pH sensors, AEIROF electrodes were reversibly modified with urease-coated magnetic microparticles (MP) using a magnet. The urea pH sensor provided fast detection of urea between 78μM and 20mM in saline solution, in sample volumes of just 50μL. The applicability to urea determination in real urine samples is discussed. 相似文献
837.
A Cytosolic Serine Endopeptidase from Trypanosoma cruzi Is Required for the Generation of Ca2+ Signaling in Mammalian Cells 下载免费PDF全文
Barbara A. Burleigh Elisabet V. Caler Paul Webster Norma W. Andrews 《The Journal of cell biology》1997,136(3):609-620
An early event in the Trypanosoma cruzi cell invasion process, the recruitment of host lysosomes, led us to investigate the involvement of signal transduction. Infective trypomastigotes were found to contain a soluble Ca2+-signaling activity for mammalian cells that is sensitive to protease inhibitors. Inhibitor and substrate utilization profiles were used to purify a candidate peptidase for involvement in this process, from which we isolated a full-length cDNA clone. The sequence revealed a novel enzyme, denominated T. cruzi oligopeptidase B, which is homologous to members of the prolyl oligopeptidase family of serine hydrolases, known to participate in the maturation of biologically active peptides. The T. cruzi oligopeptidase B was expressed as a fully active product in Escherichia coli, and antibodies to the recombinant enzyme inhibited both peptidase activity and Ca2+ signaling induced in normal rat kidney cells by trypomastigote extracts. Our data suggest that the T. cruzi oligopeptidase B participates in processing events in the cytoplasm of the parasites, generating a factor with Ca2+-signaling activity for mammalian cells. 相似文献
838.
Elisabet Forsgren Charlotta Kvarnemo Kai Lindstrm 《Evolution; international journal of organic evolution》1996,50(2):646-654
We used field observations and experiments to show that sexual selection in two populations of sand gobies, Pomatoschistus minutus (Pisces, Gobiidae), was affected by differences in resource availability. Male sand gobies rely on empty mussel shells for nest building and spawning. The two populations differed considerably in nest-site abundance and sexual-selection regimes. In one population nest sites were scarce, leading to stronger male-male competition over nests, a higher nest site colonization rate and reduced potential for female choice compared with the other population that had a surplus of nests. In the high-competition population, males were larger than females, perhaps as a response to selection, whereas the other population was not sexually size dimorphic. The results from the field were confirmed in a pool experiment that demonstrated the effect of nest abundance on nest occupancy and male reproductive success. Larger males were more successful in obtaining nest sites in both high and low nest availability treatments. Larger males were also favored by females as mating partners, but only in the treatment with surplus nest sites. Nest shortage was associated with an increased potential for intrasexual selection (measured as the coefficient of variation), whereas the potential for intersexual selection was increased when nests were common. In conclusion, nest-site abundance can influence the relative contribution of intrasexual competition and mate choice in a population. Hence, resource availability can contribute to within-species variation in mating patterns. 相似文献
839.
Increased water‐use efficiency translates into contrasting growth patterns of Scots pine and sessile oak at their southern distribution limits 下载免费PDF全文
Elisabet Martínez‐Sancho Isabel Dorado‐Liñán Emilia Gutiérrez Merino Michael Matiu Gerhard Helle Ingo Heinrich Annette Menzel 《Global Change Biology》2018,24(3):1012-1028
In forests, the increase in atmospheric CO2 concentrations (Ca) has been related to enhanced tree growth and intrinsic water‐use efficiency (iWUE). However, in drought‐prone areas such as the Mediterranean Basin, it is not yet clear to what extent this “fertilizing” effect may compensate for drought‐induced growth reduction. We investigated tree growth and physiological responses at five Scots pine (Pinus sylvestris L.) and five sessile oak (Quercus petraea (Matt.) Liebl.) sites located at their southernmost distribution limits in Europe for the period 1960–2012 using annually resolved tree‐ring width and δ13C data to track ecophysiological processes. Results indicated that all 10 natural stands significantly increased their leaf intercellular CO2 concentration (Ci), and consequently iWUE. Different trends in the theoretical gas‐exchange scenarios as a response to increasing Ca were found: generally, Ci tended to increase proportionally to Ca, except for trees at the driest sites in which Ci remained constant. Ci from the oak sites displaying higher water availability tended to increase at a comparable rate to Ca. Multiple linear models fitted at site level to predict basal area increment (BAI) using iWUE and climatic variables better explained tree growth in pines (31.9%–71.4%) than in oak stands (15.8%–46.8%). iWUE was negatively linked to pine growth, whereas its effect on growth of oak differed across sites. Tree growth in the western and central oak stands was negatively related to iWUE, whereas BAI from the easternmost stand was positively associated with iWUE. Thus, some Q. petraea stands might have partially benefited from the “fertilizing” effect of rising Ca, whereas P. sylvestris stands due to their strict closure of stomata did not profit from increased iWUE and consequently showed in general growth reductions across sites. Additionally, the inter‐annual variability of BAI and iWUE displayed a geographical polarity in the Mediterranean. 相似文献
840.
Josep Alós Elisabet Bujosa-Homar Jorge Terrados Fiona Tomas 《Biological invasions》2018,20(11):3193-3205
The establishment of non-native habitat-forming seaweeds into new areas may trigger important changes in ecosystem functioning, yet their community and ecosystem-level effects remain largely understudied. Here we studied the spatial distribution of two common fish species (Xyrichtys novacula and Bothus podas) which are key components of communities in unconsolidated bottoms of temperate areas regarding the colonization of the newly-introduced tropical seaweed Halimeda incrassata in the Mediterranean Sea. We used a spatially-explicit before-after-control-impact model and a unique data-set formed by 6 years of fine-scale spatial information of fish and seaweed distribution and abundance. We demonstrate a long-term alteration on the spatial distribution of X. novacula characterized by a shift towards non-native H. incrassata beds, while no effect on B. podas. The introduction of the tropical seaweed H. incrassata has led to the re-distribution of X. novacula, potentially by harbouring a greater biodiversity of species at the base of the food-web through adding biogenic structure to an otherwise bare sediment. Our work demonstrates that non-native tropical habitat-forming species have the potential to maintain or even enhance fish abundance in unconsolidated bottoms in temperate areas potentially altering the functioning of native habitats. 相似文献