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排序方式: 共有369条查询结果,搜索用时 15 毫秒
361.
E Marquez J Pavia S Laukonnen F Martos A Gomez F Rius F Sanchez de la Cuesta 《Chronobiology international》1990,7(4):277-282
The binding of different ligands to muscarinic receptors in the central nervous system is regulated by several factors. Among these are the administration of drugs, disease, ontogeny or aging. Studies carried out in rat brains have demonstrated changes in the density of the muscarinic receptors at different times of the day. These changes might be related to variations in the circadian rhythms. In this work we have studied the binding of the [3H]-N-methyl-escopolamine, the agonist carbachol and the antagonist pirenzepine to muscarinic receptors in rat forebrains at 10.00, 14.00, 18.00, 22.00, 02.00 and 06.00 hr. We have observed changes in the density of muscarinic receptors but not changes in affinity to the radioligand. The Bmax values obtained by saturation studies were maximum at 14.00 hr and minimum at 02.00 hr (P less than 0.05 Mann-Whitney's test). Inhibition studies in the presence of the non-selective agonist carbachol and the selective antagonist pirenzepine, at the same time-points, did not show statistically significant changes in the Bmax values. These data indicate that changes in the Bmax values are only observed in the total population of muscarinic receptors and are not due to modifications in the subtypes of muscarinic receptors nor to the different affinity states of agonist binding. 相似文献
362.
363.
J. A. Cuesta E. González-Ortegón A. Rodríguez F. Baldó C. Vilas P. Drake 《Hydrobiologia》2006,557(1):85-95
Monthly samples were taken from May 1997 to March 2002 at three sampling sites within the last 32 km of the Guadalquivir Estuary.
Twenty-four decapod crustacean species were recorded of which Crangon crangon (Linnaeus), Melicertus kerathurus (Forskal), and Palaemon spp. represented 99% of all collected individuals. These three dominant species showed a similar seasonal density pattern
even though peaks in M. kerathurus were lower. Their densities were positively correlated (p < 0.01) with water temperature and salinity, but negatively with turbidity. The highest correlation corresponded to temperature
in Palaemon spp. and to salinity in C. crangon and M. kerathurus. Therefore, the total estuarine decapod density also showed a regular seasonal pattern having the lowest figures in late
autumn and winter and the highest in spring and summer. In addition, it was positively correlated with water temperature and
salinity, but negatively with turbidity. Density decreased upstream, mainly due to the higher density of C. crangon and M. kerathurus in more saline waters. Non-metric multi-dimensional scaling ordination of samples also indicated a regular seasonal change
in the community, even though inter-year differences between dry and rainy winters were especially great. The first ordination
axis was significantly correlated with environmental variables, while the second axis seemed to split samples up following
seasonal community changes in species’ composition and dominance. 相似文献
364.
Sergio Martínez?Cuesta Syed?Asad Rahman Nicholas Furnham Janet?M. Thornton 《Biophysical journal》2015,109(6):1082-1086
Enzymes are the proteins responsible for the catalysis of life. Enzymes sharing a common ancestor as defined by sequence and structure similarity are grouped into families and superfamilies. The molecular function of enzymes is defined as their ability to catalyze biochemical reactions; it is manually classified by the Enzyme Commission and robust approaches to quantitatively compare catalytic reactions are just beginning to appear. Here, we present an overview of studies at the interface of the evolution and function of enzymes. 相似文献
365.
Elena Marco‐Herrero Asvin P. Torres José A. Cuesta Guillermo Guerao Ferran Palero Pere Abelló 《Zoologica scripta》2013,42(4):427-439
The complete larval series (zoea I, zoea II and megalopa) of the crab Ergasticus clouei is described and illustrated based on plankton samples from Mediterranean waters. The zoea II and megalopal stages, previously unknown, are described here for the first time. Nucleotide sequence analysis of two gene regions (16S rDNA and Cox1 genes) confirmed the assignment of these larvae to Ergasticus clouei. The molecular analyses and the morphology of the larval stages revealed large differences between Ergasticus and Inachus, the type genus of the family Inachidae. In fact, E. clouei larvae presented a series of morphological characters, such as antennal shape and mouthparts setation pattern that placed them closer to the family Oregoniidae. The phylogenetic analyses also showed significant support for the monophyly of the Oregoniidae + Ergasticus group. The data argue for removal of Ergasticus and the related genera (Bothromaia, Pleisticanthoides, Parapleisticantha and Pleistacantha) from the Inachidae and their placement within the Oregoniidae as a separate subfamily, Pleistacanthinae ?tev?i?, 2005. Our results demonstrate that larval stages provide reliable morphological traits, independent from those of adults, to help resolving relationships among Majoidea genera. 相似文献
366.
G. Cuesta A. Soler J. L. Alonso M. A. Ruvira T. Lucena D. R. Arahal M. Goodfellow 《Antonie van Leeuwenhoek》2013,103(1):135-142
A novel actinomycete, designated PA3T, was isolated from an oil refinery wastewater treatment plant, located in Palos de la Frontera, Huelva, Spain, and characterized taxonomically by using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate formed a distinct subclade in the Pseudonocardia tree together with Pseudonocardia asaccharolytica DSM 44247T. The chemotaxonomic properties of the isolate, for example, the presence of MK-8 (H4) as the predominant menaquinone and iso-C16:0 as the major fatty acid, are consistent with its classification in the genus Pseudonocardia. DNA:DNA pairing experiments between the isolate and the type strain of P. asaccharolytica DSM 44247T showed that they belonged to separate genomic species. The two strains were readily distinguished using a combination of phenotypic properties. Consequently, it is proposed that isolate PA3T represents a novel species for which the name Pseudonocardia hispaniensis sp. nov. is proposed. The type strain is PA3T (= CCM 8391T = CECT 8030T). 相似文献
367.
Eduardo Cires Matthias Baltisberger Candela Cuesta Pablo Vargas José Antonio Fernández Prieto 《Organisms Diversity & Evolution》2014,14(1):1-10
The Balkan Peninsula, characterized by high rates of endemism, is recognised as one of the most diverse and species-rich areas of Europe. However, little is known about the origin of Balkan endemics. The present study addresses the phylogenetic position of the Balkan endemic Ranunculus wettsteinii, as well as its taxonomic status and relationship with the widespread R. parnassiifolius, based on nuclear DNA (internal transcribed spacer, ITS) and plastid regions (rpl32-trnL, rps16-trnQ, trnK-matK and ycf6-psbM). Maximum parsimony and Bayesian inference analyses revealed a well-supported clade formed by accessions of R. wettsteinii. Furthermore, our phylogenetic and network analyses supported previous hypotheses of a likely allopolyploid origin for R. wettsteinii between R. montenegrinus and R. parnassiifolius, with the latter as the maternal parent. 相似文献
368.
F. Alfonso J. Restrepo J. Cuesta T. Bastante F. Rivero A. Benedicto 《Netherlands heart journal》2015,23(5):287-288
A patient presenting with ‘edge’ in-stent restenosis 12 years after the implantation of a bare-metal stent in the mid-left anterior descending coronary artery is described. Optical coherence tomography disclosed the presence of ruptured neoatherosclerosis at the stent edge. The value of this imaging technique to unravel this unique underlying anatomic substrate is discussed. The therapy of choice for patients presenting with edge in-stent restenosis (ISR) is reviewed. 相似文献
369.