Cerdanyola del Vallès, Spain
Cerdanyola del Vallès, Spain

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PubMed | CSIC - National Center for Biotechnology, Hospital Of La Princesa and ALBA Synchrotron Light Source
Type: Journal Article | Journal: European journal of immunology | Year: 2016

Lymphocyte migration, which is essential for effective immune responses, belongs to the so-called amoeboid migration. The lymphocyte migration is up to 100 times faster than between mesenchymal and epithelial cell types. Migrating lymphocytes are highly polarized in three well-defined structural and functional zones: uropod, medial zone, and leading edge (LE). The actiomyosin-dependent driving force moves forward the uropod, whereas massive actin rearrangements protruding the cell membrane are observed at the LE. These actin rearrangements resemble those observed at the immunological synapse driven by clathrin, a protein normally involved in endocytic processes. Here, we used cell lines as well as primary lymphocytes to demonstrate that clathrin and clathrin adaptors colocalize with actin at the LE of migrating lymphocytes, but not in other cellular zones that accumulate both clathrin and actin. Moreover, clathrin and clathrin adaptors, including Hrs, the clathrin adaptor for multivesicular bodies, drive local actin accumulation at the LE. Clathrin recruitment at the LE resulted necessary for a complete cell polarization and further lymphocyte migration in both 2D and 3D migration models. Therefore, clathrin, including the clathrin population associated to internal vesicles, controls lymphocyte migration by regulating actin rearrangements occurring at the LE.


Sorrentino A.,ALBA Synchrotron Light Source | Nicolas J.,ALBA Synchrotron Light Source | Valcarcel R.,ALBA Synchrotron Light Source | Chichon F.J.,CSIC - National Center for Biotechnology | And 6 more authors.
Journal of Synchrotron Radiation | Year: 2015

The performance of MISTRAL is reported, the soft X-ray transmission microscopy beamline at the ALBA light source (Barcelona, Spain) which is primarily dedicated to cryo soft X-ray tomography (cryo-SXT) for three-dimensional visualization of whole unstained cells at spatial resolutions down to 30 nm (half pitch). Short acquisition times allowing for high-throughput and correlative microscopy studies have promoted cryo-SXT as an emerging cellular imaging tool for structural cell biologists bridging the gap between optical and electron microscopy. In addition, the beamline offers the possibility of imaging magnetic domains in thin magnetic films that are illustrated here with an example. © 2015 International Union of Crystallography.


Oton J.,CSIC - National Center for Biotechnology | Sorzano C.O.S.,CSIC - National Center for Biotechnology | Marabini R.,Polytechnic University of Mozambique | Pereiro E.,ALBA Synchrotron Light Source | Carazo J.M.,CSIC - National Center for Biotechnology
Optics Express | Year: 2015

Soft X-ray tomography (SXT) is becoming a powerful imaging technique to analyze eukaryotic whole cells close to their native state. Central to the analysis of the quality of SXT 3D reconstruction is the estimation of the spatial resolution and Depth of Field of the X-ray microscope. In turn, the characterization of the Modulation Transfer Function (MTF) of the optical system is key to calculate both parameters. Consequently, in this work we introduce a fully automated technique to accurately estimate the transfer function of such an optical system. Our proposal is based on the preprocessing of the experimental images to obtain an estimate of the input pattern, followed by the analysis in Fourier space of multiple orders of a Siemens Star test sample, extending in this way its measured frequency range. © 2015 Optical Society of America.


Pesquera D.,CSIC - Institute of Materials Science | Scigaj M.,CSIC - Institute of Materials Science | Scigaj M.,Autonomous University of Barcelona | Gargiani P.,ALBA Synchrotron Light Source | And 11 more authors.
Physical Review Letters | Year: 2014

Recent findings show the emergence of two-dimensional electron gases (2DEGs) at LaAlO3/SrTiO3 interfaces along different orientations; yet details on band reconstructions have remained so far unknown. Via x-ray linear dichroism spectroscopy, we demonstrate that crystal symmetry imposes distinctive 2DEG orbital hierarchies on (001)-and (110)-oriented quantum wells, allowing selective occupancy of states of different symmetry. Such orientational tuning expands the possibilities for electronic engineering of 2DEGs and opens up enticing opportunities to understand the link between orbital symmetry and complex correlated states at LaAlO3/SrTiO3 quantum wells. © 2014 American Physical Society.


Olivares-Marin M.,CSIC - Institute of Materials Science | Sorrentino A.,ALBA Synchrotron Light Source | Lee R.-C.,National Taiwan University | Pereiro E.,ALBA Synchrotron Light Source | And 2 more authors.
Nano Letters | Year: 2015

The discharge products of ether-based Li-O2 cells were grown directly on common carbon-coated TEM grids and observed by oxidation-state-sensitive full field transmission soft X-ray microscopy (TXM). The acquired data have permitted to quantify and localize with spatial resolution the distribution of the oxygen discharge products in these samples (i.e., lithium superoxide, peroxide, and carbonates) and appreciate several compositional, structural, and morphological aspects. Most of the peroxide particles had a toroidal shape, often with a central hole usually open on only one side, and which included significant amounts of superoxide-like phases (LiO2/Li2O2 ratio between 0.2 and 0.5). Smaller particles had smaller or no superoxide content, from which we infer that abundance of soluble LiO2 may have a role in toroid formation. Significant amount of carbonates were found irregularly distributed on the electrode surface, occasionally appearing as small particles and aggregates, and mostly coating lithium peroxide particles. This suggests the formation of a barrier that, similar to the solid electrolyte interface (SEI) critical in Li-ion batteries, requires an appropriate management for a reversible operation. © 2015 American Chemical Society.


PubMed | Helmholtz Center Berlin, U.S. National Institutes of Health and ALBA Synchrotron Light Source
Type: Journal Article | Journal: Journal of the American Chemical Society | Year: 2016

We have developed a high resolution correlative method involving cryo-soft X-ray tomography (cryo-SXT) and stochastic optical reconstruction microscopy (STORM), which provides information in three dimensions on large cellular volumes at 70 nm resolution. Cryo-SXT morphologically identified and localized aggregations of carbon-rich materials. STORM identified specific markers on the desired epitopes, enabling colocalization between the identified objects, in this case cholesterol crystals, and the cellular environment. The samples were studied under ambient and cryogenic conditions without dehydration or heavy metal staining. The early events of cholesterol crystal development were investigated in relation to atherosclerosis, using as model macrophage cell cultures enriched with LDL particles. Atherosclerotic plaques build up in arteries in a slow process involving cholesterol crystal accumulation. Cholesterol crystal deposition is a crucial stage in the pathological cascade. Our results show that cholesterol crystals can be identified and imaged at a very early stage on the cell plasma membrane and in intracellular locations. This technique can in principle be applied to other biological samples where specific molecular identification is required in conjunction with high resolution 3D-imaging.


Lopez-Periago A.,CSIC - Institute of Materials Science | Vallcorba O.,ALBA Synchrotron Light Source | Domingo C.,CSIC - Institute of Materials Science | Ayllon J.A.,Autonomous University of Barcelona
Crystal Growth and Design | Year: 2016

An innovative crystallization process, based on the use of the ecofriendly supercritical carbon dioxide (scCO2) solvent, is presented for the production of coordination compound macrocrystals of general formula [Cu(hfacac)2(dPy)2], with intriguing prismatic hollow structures and single polymorphic forms. In contrast, conventional solvents yielded compact microstructures. The studied pyridine derivatives (dPy) were 4-phenylpyridine, PhPy; 4-benzylylpyridine, BzPy; and 4-acetylpyridine, AcPy. In the specific case of the [Cu(hfacac)2(AcPy)2] adduct, the use of scCO2 as a solvent allowed obtaining a pure polymorph, while the conventional solvent trials yielded a mixture of two polymorphs. Four new crystalline structures have been resolved from single crystal X-ray diffraction. All the structures consist of mononuclear complexes connected through intermolecular interactions, including H⋯;H, H⋯;O, F⋯;F, C-F⋯;Caromatic, and/or C-F⋯;π interactions, generating bi-dimensional networks that determine their crystallization mode in scCO2. © 2016 American Chemical Society.


Ferrer S.,ALBA Synchrotron Light Source
Synchrotron Radiation News | Year: 2016

ALBA is the Spanish synchrotron facility located in the area of Barcelona. It is a low-emittance, 3 GeV machine having, at present, seven state-of-the-art operating beamlines covering soft and hard X-rays. The hard X-ray beamlines comprise macromolecular crystallography, non-crystalline diffraction (SAXS and WAXS), high-resolution powder diffraction, and absorption spectroscopy. The soft X-ray beamlines include a photoemission beamline with two endstations—one devoted to photoelectron microscopy (PEEM) and the second to near ambient pressure photoemission (NAPP)—and another beamline devoted to XMCD and soft X-ray scattering. Both beamlines allow full control of the polarization of the beam, since they are equipped with helical undulators. An additional soft X-ray beamline, installed on a bending magnet port, is equipped with a full-field transmission X-ray microscope. Additional information may be found at http://www.albasynchrotron.es/en/beamlines. © , Copyright Taylor & Francis.

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