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991.
David Núñez María Pilar Domingo Diego Sánchez-Martínez Vicente Cebolla Arthur Chiou Adrián Velázquez-Campoy Julián Pardo Eva Ma Gálvez 《Process Biochemistry》2013,48(4):708-715
The interaction of the adhesion molecule of the immunoglobulin family intercellular adhesion molecule 1 (ICAM-1) with its ligands such that the integrins LFA-1 and Mac-1 is crucial for the regulation of several physiological and pathophysiological processes like cell mediated-elimination of tumor or virus infected cells, cancer metastasis or inflammatory autoimmune processes. Thus, production of milligrams of protein is required to perform structural and functional studies as well as design novel approaches to find out new inhibitors of ICAM-1/LFA-1 interaction. Here we report on the production of a recombinant human ICAM-1 chimera comprising the first two extracellular domains of ICAM-1 linked to the Fc fraction of a human IgG1. To this aim we have used a cost-effective method based on the expression of a His-tagged protein in Escherichia coli followed by a single step of refolding and purification on immobilized metal affinity columns. This method is able to produce 3 mg/l of bacterial culture in just 72 h with purity greater than 95%. The identity and the native structure of refolded human ICAM-1 chimera were confirmed by biochemical and biophysical studies including SDS-electrophoresis, immunoblot, circular dichroism, isothermal titration calorimetry and fluorescence spectroscopy. Native folding and functional activity of the chimera were further confirmed by different cell biology studies, including B cell adhesion, T cell binding and inhibition of NK cell function. These studies indicate a high biological activity of the protein since it induces a 200-fold increase/mg of protein in B cell adhesion and the inhibitory dose 50 to block cell-mediated cytotoxicity is 10 pg/effector cell. These analyses show that our protocol is able to produce a recombinant human ICAM-1 chimera fully active and useful to analyze the biological processes in which ICAM-1/LFA-1 interaction is critically involved. 相似文献
992.
Susanna López‐Legentil Patrick M. Erwin Marta Velasco Xavier Turon 《Invertebrate Biology》2013,132(1):69-80
Relatively little is known about the life cycles of ascidians in temperate seas. Here, we investigated the biological cycle of the colonial ascidian Didemnum fulgens, a dominant species in some shallow localities of the NW Mediterranean Sea. Growth rates and frequencies of fission/fusion events were calculated over a period of 13 months, and the reproductive cycle determined after 32 months of observation. For analyses of reproduction, zooids were dissected in the laboratory and classified into five reproductive categories; these data were used to calculate a maturity index. For growth analyses, underwater photographs of marked colonies were used to estimate the surface area of D. fulgens colonies, calculate monthly growth rates, and document fusion and fission events. Clear seasonal patterns in reproduction and growth were observed, with distinct periods of investment into each function. Gonad maturation started in winter and larval release occurred in early summer, just before maximal sea temperatures were reached. After reproducing, colonies shrank and aestivated during the warmer summer months. Growth occurred during the cooler months, with maximal and minimal growth rates observed in winter and summer, respectively. Fusions and fissions occurred year‐round, although fissions were more frequent in fall (coincident with high growth rates) and fusions in spring (coincident with reproduction). These results add to the mounting evidence that ascidian life cycles in temperate seas are characterized by a trade‐off between investment in reproduction and growth, triggered by seasonal temperature shifts and constrained by resource availability during summer. 相似文献
993.
Pilar Morera‐Margarit Tom W. Pope Carolyn Mitchell Alison J. Karley 《The Annals of applied biology》2021,178(1):51-61
The weevil superfamily Curculionoidea is the largest insect group and so the largest animal group on earth. This taxon includes species which represent an important threat to many economically important crops and, therefore, pose a risk to agriculture and food security. Insect–bacteria associations have been recognised to provide the insect host with many benefits, such as ensuring the acquisition of essential nutrients or protecting the host from natural enemies. The role of bacteria associations within the weevil superfamily remains nonetheless understudied in comparison with other insect taxa. This review draws together existing knowledge on the influence of bacteria associated with weevils known to be agricultural pest species. The implications of these weevil–bacterial associations in determining pest status and their relevance to targeted pest management interventions are discussed. Specific consideration is given to the role of bacteria in cuticle formation, flight activity, reproduction manipulation and adaptation to different environments and food sources. 相似文献
994.
Pereira Luiz Henrique Garcia Castro Jerson Rogelio Chanchay Vargas Pilar Mireya Huatatoca Gomez Jose Alejandro Morales Oliveira Claudio 《Genetica》2021,149(2):103-116
Genetica - In this study, we made an inventory of the stream and headwater ichthyofauna of the left bank of the Itaipu Dam Reservoir, located in the lower part of the Upper Paraná River basin,... 相似文献
995.
Montero-Muñoz Jorge Luis Ureña Carmen Navarro Diego Herrera Valentín Alonso-Rojo Pilar Hernández-Alonso Héctor Cepeda-González María Fernanda Jovellar Luis Carlos Fernández-Santos Belén Silla Fernando 《Plant and Soil》2021,462(1-2):311-329
Plant and Soil - Biological soil crusts (biocrusts) are commonly found in semi-arid ecosystems and complete biological nitrogen (N) fixation, build soil carbon (C) stocks, and increase soil... 相似文献
996.
Marrades MP González-Muniesa P Arteta D Martínez JA Moreno-Aliaga MJ 《Journal of physiology and biochemistry》2011,67(1):15-26
There are major variations in the susceptibility to weight gain among individuals under similar external influences (decreased
physical activity and excessive calorie intake), depending on the genetic background. In the present study, we performed a
microarray analysis and real-time PCR validations in order to find out differential gene expression in subcutaneous abdominal
adipose tissue from two groups of subjects that despite living in similar environmental conditions such as a habitual high-fat
dietary intake (energy as fat >40%) and similar moderate physical activity, some of them were successfully “resistant” (lean)
to weight gain, while others were “susceptible” to fat deposition (obese). The classification of up- and downregulated genes
into different categories, together with the analysis of the altered biochemical pathways, revealed a coordinated downregulation
of catabolic pathways operating in the mitochondria: fatty acid β oxidation (P = 0.008), tricarboxylic acid cycle (P = 0.001), and electron transport chain (P = 0.012). At the same time, glucose metabolism (P = 0.010) and fatty acid biosynthesis (P = 0.011) pathways were also downregulated in obese compared to lean subjects. In conclusion, our data showed an orchestrated
downregulation of nuclear-encoded mitochondrial gene expression. These genes are involved in cellular respiration and oxidative
metabolic pathways and could play a role in the susceptibility to weight gain in some individuals. 相似文献
997.
998.
Fernández-Trillo F Pacheco-Torres J Correa J Ballesteros P Lopez-Larrubia P Cerdán S Riguera R Fernandez-Megia E 《Biomacromolecules》2011,12(8):2902-2907
The Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) allows the efficient and complete functionalization of dendrimers with preformed Gd chelates (prelabeling) to give monodisperse macromolecular contrast agents (CAs) for magnetic resonance imaging (MRI). This monodispersity contrasts with the typical distribution of materials obtained by classical routes and facilitates the characterization and quality control demanded for clinical applications. The potential of a new family of PEG-dendritic CA based on a gallic acid-triethylene glycol (GATG) core functionalized with up to 27 Gd complexes has been explored in vitro and in vivo, showing contrast enhancements similar to those of Gadomer-17, which reveals them to be a promising platform for the development of CA for MRI. 相似文献
999.
Guglielmini J Quintais L Garcillán-Barcia MP de la Cruz F Rocha EP 《PLoS genetics》2011,7(8):e1002222
Horizontal gene transfer shapes the genomes of prokaryotes by allowing rapid acquisition of novel adaptive functions. Conjugation allows the broadest range and the highest gene transfer input per transfer event. While conjugative plasmids have been studied for decades, the number and diversity of integrative conjugative elements (ICE) in prokaryotes remained unknown. We defined a large set of protein profiles of the conjugation machinery to scan over 1,000 genomes of prokaryotes. We found 682 putative conjugative systems among all major phylogenetic clades and showed that ICEs are the most abundant conjugative elements in prokaryotes. Nearly half of the genomes contain a type IV secretion system (T4SS), with larger genomes encoding more conjugative systems. Surprisingly, almost half of the chromosomal T4SS lack co-localized relaxases and, consequently, might be devoted to protein transport instead of conjugation. This class of elements is preponderant among small genomes, is less commonly associated with integrases, and is rarer in plasmids. ICEs and conjugative plasmids in proteobacteria have different preferences for each type of T4SS, but all types exist in both chromosomes and plasmids. Mobilizable elements outnumber self-conjugative elements in both ICEs and plasmids, which suggests an extensive use of T4SS in trans. Our evolutionary analysis indicates that switch of plasmids to and from ICEs were frequent and that extant elements began to differentiate only relatively recently. According to the present results, ICEs are the most abundant conjugative elements in practically all prokaryotic clades and might be far more frequently domesticated into non-conjugative protein transport systems than previously thought. While conjugative plasmids and ICEs have different means of genomic stabilization, their mechanisms of mobility by conjugation show strikingly conserved patterns, arguing for a unitary view of conjugation in shaping the genomes of prokaryotes by horizontal gene transfer. 相似文献
1000.
Ribeiro AS Fernandes VS Orensanz LM Martínez MP Recio P Martínez-Sáenz A Climent B Arteaga JL García-Sacristán A Prieto D Hernández M 《Purinergic signalling》2011,7(4):413-425
Benign prostatic hypertrophy has been related with glandular ischemia processes and adenosine is a potent vasodilator agent. This study investigates the mechanisms underlying the adenosine-induced vasorelaxation in pig prostatic small arteries. Adenosine receptors expression was determined by Western blot and immunohistochemistry, and rings were mounted in myographs for isometric force recording. A2A and A3 receptor expression was observed in the arterial wall and A2A-immunoreactivity was identified in the adventitia–media junction and endothelium. A1 and A2B receptor expression was not obtained. On noradrenaline-precontracted rings, P1 receptor agonists produced concentration-dependent relaxations with the following order of potency: 5′-N-ethylcarboxamidoadenosine (NECA) = > 2-Cl-IB-MECA = 2-Cl-cyclopentyladenosine = adenosine. Adenosine reuptake inhibition potentiated both NECA and adenosine relaxations. Endothelium removal and ZM241385, an A2A antagonist, reduced NECA relaxations that were not modified by A1, A2B, and A3 receptor antagonists. Neuronal voltage-gated Ca2+ channels and nitric oxide (NO) synthase blockade, and adenylyl cyclase activation enhanced these responses, which were reduced by protein kinase A inhibition and by blockade of the intermediate (IKCa)- and small (SKCa)-conductance Ca2+-activated K+ channels. Inhibition of cyclooxygenase (COX), large-conductance Ca2+-activated-, ATP-dependent-, and voltage-gated-K+ channel failed to modify these responses. These results suggest that adenosine induces endothelium-dependent relaxations in the pig prostatic arteries via A2A purinoceptors. The adenosine vasorelaxation, which is prejunctionally modulated, is produced via NO- and COX-independent mechanisms that involve activation of IKCa and SKCa channels and stimulation of adenylyl cyclase. Endothelium-derived NO playing a regulatory role under conditions in which EDHF is non-functional is also suggested. Adenosine-induced vasodilatation could be useful to prevent prostatic ischemia. CGS21680相似文献