Destacados

Cada año, un comité de expertos debe acometer una ardua tarea: de entre todas las publicaciones de ICREA, debe escoger unas cuantas que destaquen del resto. Es todo un reto: a veces los debates se acaloran, y siempre son difíciles, pero acaba saliendo una lista con las mejors publicaciones del año. No se concede ningún premio, y el único reconocimiento adicional es el honor de ser resaltado en la web de ICREA. Cada publicación tiene algo especial, ya sea una solución especialmente elegante, un éxito espectacular en los medios de comunicación o la simple fascinación por una idea del todo nueva. Independientemente de la razón, se trata de los mejores de los mejores y, como tales, nos complace compartirlos aquí.

LIST OF SCIENTIFIC HIGHLIGHTS

Format: yyyy
  • Key to robustness of plants discovered (2019)

    Rovira Virgili, Carme (UB)

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    Key to robustness of plants discovered

    In changing weather situations, plants need to be robust and flexible at the same time. These structural properties are anchored in the cell walls. The cell wall is responsible for defining the plant’s shape, for compensating its osmotic pressure and to protect it against pathogens e.g. bacteria, viruses or fungal attacks. The cell walls of plants are largely built from polymers and the polysaccharide cellulose. As binding agents, polysaccharides have the important task to connect long-chain polymers and to build a molecular network of tiny strands, called fibrils, which contribute to the tensile strength of the plant. 

    One of the sugar building blocks is the branched-chain monosaccharid apiose, which got its name from the latin word "apium“, a plant genus comprising, for instance, celeriac and parsley.

    Apiose has been investigated by plant-biochemical research for more than a hundred years and its function in plants is still not fully understood. Besides, the mechanism, which is responsible for the production of apiose in nature, was still unknown.

    Scientists from the Universities of Barcelona (Spain), Pavia (Italy) and TU Graz (Austria) discovered how apiose is produced by a single enzyme called UAXS (UDP-apiose/UDP-xylose synthase). They were able to decode the entire mechanism of this enzyme for the first time. Isolated from the cress Arabidopsis thaliana, the catalyst possesses special properties: whereas most biosynthetic processes for the manufacturing of complex molecules need several reaction steps, the UAXS-enzyme selectively catalyzes in just four reaction steps. By doing so, the enzyme is able to break down organic carbon compounds as well as to establish new molecular compounds. This results in the change from a six ring sugar molecule (hexose) to a structurally simpler five ring sugar (pentose). By creating new organic carbon compounds, the enzyme is responsible for giving plants their strength properties.

    The discovery of the enzymatic mechanism of apiose was possible due to the interdisciplinary collaboration between the research areas of molecular modeling, enzymology and biocatalysis and structural biology.

  • Self-powered, paper-based sweat detector for easy screening of cystic fibrosis (2019)

    Sabaté Vizcarra, Neus (CSIC - IMB-CNM )

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    Self-powered, paper-based sweat detector for easy screening of cystic fibrosis

    Sabate’s team has developed the Power-Patch, a self-powered skin patch for the measurement of sweat conductivity that can potentially be used as a screening device of Cystic Fibrosis disease. The key component of the patch consists of a paper battery that is activated upon adding the sweat. The fluid acts as an electrolyte, and for a particular configuration of the battery materials and design, the battery output is fully dependent on the conductivity of the liquid sample that is poured in its paper core. This approach enables the sensor and battery to be merged in a single element—a battery sensor—whose generated power is directly related to the conductivity of the sample to be analysed.

    The battery has been integrated into a patch and tested with artificial sweat samples mimicking healthy and non-healthy conditions of CF patients. The patch is conceived to be applied on the forearm of the patient and yield a “positive” result in case of an abnormal conductivity level of sweat is detected. The patch remains quiescent until sufficient sweat is absorbed by its paper-based electroactive core, which is in contact with the skin. After sweat absorption, the battery generates electrical power that is managed with a minimalistic electronic circuit that discerns between a healthy and a non-healthy condition. After providing a result, the patch can be disposed of with little environmental impact.

    The patch will enable an easy screening of the CF condition in regional hospitals or clinics, providing a powerful yet affordable tool for early identification of patients in developing countries. The innovation potential of the skin patch was acknowledged by the Organic Electronics Association, who awarded the prototype for the best prototype/new product at the annual contest that took place at the European Large-area, Organic and Printed Electronics Convention in 2018. After a successful lab validation, the patch will undergo a feasibility test with patients in 2020 with the Cystic Fibrosis Unit from Hospital Sant Joan de Deu (Barcelona) within the frame of an ERC Proof-of-Concept grant.

  • Why do enzymes make micromotors swim? (2019)

    Sánchez Ordónez, Samuel (IBEC)
    Osuna Oliveras, Sílvia (UdG)

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    Why do enzymes make micromotors swim?

    Inspired by biological motors, researchers have engineered artificial micro- and nanoswimmers able to self-propel by converting chemical energy from their surrounding into motion. In our group, we pioneered the use of enzymes as engines, which catalyse bioavailable substrates (fuel) into products, providing nanomotors with a biocompatible propulsive source and therefore opening many possibilities for nanomedicine-related applications. Although there are a few reports on enzyme-nanomotors, the key properties to generate self-propulsion have not been studied so far.

    In this work, we aim at understanding at fundamental level the enzyme properties that predict the best performance of micromotors. To do so, we selected four different enzymes, urease, acetylcholinesterase, glucose oxidase and aldolase, to catalyze their specific “fuels” when bound to the surface of the micromotor. In Samuel Sánchez group (IBEC) we found that urease-motors showed the fastest self-propulsion indicating that self-propulsion of micromotors was correlated with a higher catalytic turnover of the enzyme used as engine. To gain more insight into the mechanistic structure at molecular level, in Sílvia Osuna group (IQCC at UdG), calculations based on Molecular Dynamics simulations revealed that the structural flexibility next to the active site, where the reaction occurs, of each enzyme was crucial for self-propulsion. These theoretical predictions were experimentally confirmed by exposing urease micromotors to inhibitors and compounds that increase enzyme rigidity.

    From these results we extracted that the conformational changes are a precondition to catalysis, which in its turn is the key factor for an optimal self-propulsion.

    This project has been the first study combining molecular dynamics and experimental work aimed at understanding enzyme-driven self propulsion from a mechanistic point of view. It paves the way towards the comprehension of the processes underlying catalytic self-propulsion and contributes to a more robust criteria for the rational design of enzyme-powered micromotors.

  • Mapping brain activity enabled by graphene  (2019)

    Sánchez-Vives, María Victoria (FRCB-IDIBAPS)
    Garrido Ariza, Jose A. (ICN2)
    Durduran, Turgut (ICFO)

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    Mapping brain activity enabled by graphene 

    Recording infraslow brain signals (<0.1 Hz) with microelectrodes is severely hampered by current microelectrode materials, primarily due to limitations resulting from voltage drift and high electrode impedance. Hence, most recording systems include high-pass filters that solve saturation issues but come hand in hand with loss of physiological and pathological information. In this work, we used flexible epicortical and intracortical arrays of graphene solution-gated field-effect transistors (gSGFETs) to map cortical spreading depression and demonstrate that gSGFETs are able to record, with high fidelity, infraslow signals together with signals in the typical local field potential bandwidth. The wide recording bandwidth results from the direct field-effect coupling of the active transistor, in contrast to standard passive electrodes, as well as from the electrochemical inertness of graphene. Taking advantage of such functionality, we envision broad applications of gSGFET technology for monitoring infraslow brain activity both in research and in the clinic.

  • Cellular processes and their respective regulatory mechanisms     (2019)

    Serrano Pubul, Luis (CRG)

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    Cellular processes and their respective regulatory mechanisms    

    Here, we determined the relative importance of different transcriptional mechanisms in the genome-reduced bacterium Mycoplasma pneumoniae, by employing an array of experimental techniques under multiple genetic and environmental perturbations. Of the 143 genes tested (21% of the bacterium's annotated proteins), only 55% showed an altered phenotype, highlighting the robustness of biological systems. We identified nine transcription factors (TFs) and their targets, representing 43% of the genome, and 16 regulators that indirectly affect transcription. Only 20% of transcriptional regulation is mediated by canonical TFs when responding to perturbations. Using a Random Forest, we quantified the non-redundant contribution of different mechanisms such as supercoiling, metabolic control, RNA degradation, and chromosome topology to transcriptional changes. Model-predicted gene changes correlate well with experimental data in 95% of the tested perturbations, explaining up to 70% of the total variance when also considering noise. This analysis highlights the importance of considering non-TF-mediated regulation when engineering bacteria.

  • Cooling  Surfaces Without Consuming Energy? Yes, we can!  (2019)

    Sotomayor Torres, Clivia Marfa (ICN2)

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    Cooling  Surfaces Without Consuming Energy? Yes, we can! 

    Temperature regulation keeps us comfortable and ensures reliable performance of machines, like computers. Cooling systems account for 15% of the global energy consumption and are responsible for 10% of greenhouse gas emissions. Our phononics research led us to a novel 2-dimensional and plastic-free material able to remove heat, cooling down the surface on which it is placed without energy consumption or gas emissions of any kind. 

    The material is inspired by the Earth’s efficient temperature-regulation mechanism, namely, radiative sky cooling. Although our planet is heated mainly by the sun, it also emits infrared radiation to the outer space, since this kind of radiation is not captured by the atmosphere. Our material is able to cool down a silicon wafer under direct sunlight irradiation by 14 ºC, whereas an ordinary soda-lime glass just lowers it by 5 ºC. It is formed by a single layer of 8 µm diameter self-assembled array of silica spheres, like sand grains but a million times smaller. This layer behaves almost as an ideal infrared emitter, providing a radiative cooling power of up to 350 W/m2 for a hot surface, such as a solar panel.  This would remove half of the heat accumulated in a typical solar panel in a regular clear day, which is enough to increase the relative efficiency of a solar cell by 8%. Considering the global solar energy production in 2017, such an efficiency increase would represent enough energy to power the city of Paris during an entire year.  The physics behind it is the interaction of phonons (quanta of atomic lattice vibrations) and polaritons (quanta of hybrid light-matter excitation), called surface phonon polaritons (see Fig. 1), which have been studied in transport thermal energy over millimetre distances by researchers in France. The layer thickness of our material, which is six times thinner that state-of-the-art radiative cooling materials, is an added bonus. This research was awarded the Collider Tech Award 2019, a prize that encourages further development of this invention, and is protected by an European patent application.