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 de 24 publicaciones. 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
  • Incorrect number of chromosomes, gene-dosage imbalance and cancer (2016)

    Milán Kalbfleisch, Marco (IRB Barcelona)
    Rodriguez Nebreda, Angel (IRB Barcelona)

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    Incorrect number of chromosomes, gene-dosage imbalance and cancer

    Genomic instability was originally proposed to cause cancer over 100 years ago and it has been observed in most solid tumors. There are various forms of genomic instability and the most common in cancer is chromosomal instability (CIN), which refers to the high rate by which chromosome structure and number changes over time in cancer cells compared to normal cells. While CIN contributes to the gain or loss of chromosomes carrying oncogene or tumor-suppressor genes, respectively, errors in chromosome segregation cause DNA damage and chromosomal rearrangements, and the resulting aneuploidy, defined as an abnormal number of chromosomes or parts of them, compromises cell fitness.

    Marco Milán and colleagues have used the wing primordia of Drosophila to molecularly dissect the cellular and tissue-wide effects of CIN-induced aneuploidy. These wing primordia grow from 20 to 30,000 cells in 4 days and provide the advantage that individual cells can be tracked and the tissue can be manipulated genetically in a temporal and spatial manner. Previous work from the lab has shown that CIN-induced aneuploid cells are removed from the tissue by JNK-dependent apoptosis. When highly aneuploid cells are prevented from entering apoptosis, JNK drives the expression of mitogenic molecules and matrix-metalloproteases and induces tumor-like tissues that grow extensively, cause malignancy to the host and metastasize when transplanted into the abdomen of adult hosts.

    Authors have now made use of the inherent aneuploidy in male flies to unravel a role of chromosome-wide gene dosage imbalance to the effects of CIN in vivo. Authors also identify several mechanisms that buffer the deleterious effects of CIN in proliferative tissues, including activation of the DNA-damage response pathway, induction of p38 MAPK signaling to protect against reactive oxygen species (ROS), and expression of mitogenic cytokines to promote compensatory cell proliferation and restore tissue loss. Compromising the activity of these buffering mechanisms enhances the deleterious and pro-tumorigenic effects of CIN. 

  • Uncovering the relevant role of autophagy in restoring tissue regeneration during aging (2016)

    Muñoz-Cánoves, Pura (UPF)

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    Uncovering the relevant role of autophagy in restoring tissue regeneration during aging

    Dr. Pura Muñoz-Cánoves’ Group recently published in Nature one possible explanation for the loss of tissue regenerative capacity with aging. In tissues with little turnover, stem cells (which repair tissues and organs) remain in a dormant, quiescent state. The stem cells of skeletal muscle (also called satellite cells) were thought to be quiescent throughout life, only activating in response to damage or stress. Dr. Muñoz-Cánoves and colleagues hypothesized that satellite cells would progressively accumulate intracellular toxic debris over their lifespan, and would therefore need an efficient ‘clean-up’ system to maintain protein homeostasis (proteostasis). These ideas led them to investigate the possible role of autophagy, a system used by cells to degrade damaged proteins and organelles in vesicular structures called lysosomes. Recent evidence shows that, at advanced, geriatric life stages, satellite cells lose quiescence and enter an irreversible state of proliferative block called senescence, leading to defective muscle regeneration. Using autophagy-reporting mice, these researchers found that adult satellite cells, despite their dormant state, maintain a basal autophagic activity. In old age, however, this activity is lost, causing accumulation of damaged mitochondria. Mitochondria are the essential organelles of energy production, and the accumulated dysfunctional mitochondria generate high levels of reactive oxygen species (ROS), causing further damage to proteins and DNA. This loss of proteostasis provokes senescence entry and impairs satellite cell functions. By reactivating autophagy or inhibiting ROS production in aged satellite cells, they were able to prevent senescence, restore stem-cell self-renewal, and reboot the capacity to form new muscle fibres. The identification of autophagy as an obligatory activity for maintaining stem-cell fitness, despite these cells’ low metabolic activity, not only advances the understanding of stem-cell biology, but also suggests research avenues into potential regenerative medicine applications.

  • How nanoparticles give electrons away (2016)

    Neyman, Konstantin M (UB)

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    How nanoparticles give electrons away

    Whether it is in catalytic processes, new types of solar cells or advanced electronic components, nanoparticles are everywhere in modern production and environmental technologies. Their remarkable properties ensure efficiency and save resources. Specialproperties of nanoparticles often arise from chemical interactions with the support material on which they are placed. Such interactions change the electronic structure of the nanoparticle when electrical charge is exchanged between the particle and the support.

    Scientists led by ICREA Professor Konstantin Neyman (Universitat de Barcelona) and Professor Jörg Libuda (Universität Erlangen-Nürnberg, Germany) have succeeded in quantifying the charge that is lost by a platinum nanoparticle when it is deposited onto a typical oxide support. Their work brings the possibility of designing nanoparticles with tailor-made properties a step closer.

    In order to measure the electrical charge exchanged between metal particles and supports the international research team from Germany, Spain, Italy and Czech Republic funded by the European Commission prepared a clean, atomically well-defined oxide surface, on which platinum nanoparticles have been placed. Using a highly sensitive detection method at Elettra Sincrotrone Trieste the researchers were able to quantify the effect for the first time. Studying particles with various numbers of atoms, from dozens to several hundreds, they measured the number of electrons transferred to the support and showed that the effect is most pronounced for small particles with around 50 atoms.

    The effect for such particles is surprisingly large: approximately every tenth metal atom loses an electron when the particle is in contact with the oxide. Using theoretical methods and computational modelling the researchers revealed how the effect can be controlled, allowing the chemical properties to be adapted to better suit the intended application. This research, published in Nature Materials magazine, should enable more efficient usage of valuable raw materials and energy, for instance, in catalytic processes.

  • Marine bacteria are sensitive to human-induced ocean acidification (2016)

    Pelejero Bou, Carles (CSIC - ICM)

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    Marine bacteria are sensitive to human-induced ocean acidification

    In addition to causing global warming, anthropogenic emissions of CO2 are altering the chemistry of Earth’s seas and oceans, turning them more acidic. This change has important implications for many organisms, especially those whose shells or skeletons are made of calcium carbonate, like corals and shellfish. Strong efforts have been devoted to study the potential effects of acidification on these particular species demonstrating, in the majority of occasions, detrimental effects. However, acidification may also interfere with the development of marine bacteria (Fig. 1), which play a crucial role in the global cycle of elements necessary to life. Bacteria act as the primary degraders of organic material produced through photosynthesis of microscopic algae in the ocean, or material released through wastewater. When algae or other organisms die and are degraded by bacteria, at the same time bacteria mediate the release of elements like nitrogen or phosphorous that are essential to the food chain. Thus, bacteria in the sea play a critical role in determining the health of marine ecosystems. In addition, bacteria synthesize vitamins on which algae and other organisms in the sea depend. Despite these important roles, possible ocean acidification effects on marine bacteria have mostly been ignored or neglected. In order to tackle this issue, we performed a metatranscriptome analyses of a phytoplankton bloom mesocosm experiment conducted at Institut de Ciències del Mar with water from the Blanes Bay, north of Barcelona (Fig. 2). Our results demonstrated that marine bacteria exposed to acidification are indeed forced to significantly alter their metabolism. In particular, they respond to low pH by enhancing the expression of genes encoding proton pumps, such as respiration complexes, proteorhodopsin and membrane transporters. Thus, bacteria need to invest extra energy for activating mechanisms to counterbalance the stress produced by acidification. This study, conducted by researchers from Catalonia, Spain and Sweden, suggests that bacterioplankton adaptation to ocean acidification could have long-term effects on the energy balance of ocean ecosystems.

  • Local environmental knowledge enhances human adaptive capacity (2016)

    Reyes García, Victoria (UAB)

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    Local environmental knowledge enhances human adaptive capacity

    Local environmental knowledge refers to the knowledge of natural resources and ecosystems and the associated management practices, beliefs, and institutions, developed by societies with long histories of interactions with particular environments. This ERC-funded research aimed to assess whether, across societies and domains of knowledge, people with more local environmental knowledge enjoy better livelihoods than people with less local environmental knowledge. Specifically, we aimed to explore the benefits that knowledge related to hunting and plants medicinal properties conferred to individuals in three indigenous societies, the Baka (Congo Basin), the Punan (Borneo), and the Tsimane’ (Amazonia).

    Overall, we found that people with more hunting knowledge obtained higher hunting yields than peoples with less hunting knowledge, and that people with more medicinal plant knowledge were sick less often than respondents with less medicinal plant knowledge. Our data, however, did not support the hypotheses that people with more hunting and/or medicinal plant knowledge have better nutritional status than other respondents in the same society. The paradoxical finding that local environmental knowledge provides some individual benefits related to their ability to obtain food and prevent sickness but –overall- does not contribute to better nutrition could potentially be explained through the prevalence of sharing and cooperation. Sharing and cooperation allow resources (i.e., bushmeat) and information (i.e., where to find a medicinal plant) to flow from the more knowledgeable or skilful to the rest of the group, thus potentially contributing to group-level improvements in nutritional status. Our study points to the idea that local knowledge systems might enhance adaptation by first boosting individual ability to obtain food and protect health and then establishing the mechanisms so that these benefits are shared across the various members of the group.

  • Understanding Spin Hall Effect in Dirac Matter (2016)

    Roche, Stephan (ICN2)
    Valenzuela, Sergio O. (ICN2)

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    Understanding Spin Hall Effect in Dirac Matter

    Spin is a fundamental quantum property of particles which behaves similarly to a permanent magnet attached to the quantum object and takes two values + or - half the Planck constant. Spin Hall effect (SHE) is a fundamental mechanism occurring in strong spin-orbit materials and which manifests as an accumulation of up and down spins at the opposite edges of a sample, upon the application of an electrical field. SHE actually converts charge to pure spin current in the direction perpendicular to the charge flow. The great challenge for developing spin-based information-processing technologies requires optimizing the spin Hall angle which measures the strength of SHE. The further use of graphene and other two-dimensional materials has sparked great expectations for the design of innovative heterostructures of superior spintronic performances which could be used in improving STT-MRAM (spin transfer-torque magnetic random access memories) technologies or engineering new spin logic architectures.

    Large values of SHE have been recently reported in graphene decorated with adatoms but those experiments have raised a considerable debate, given the complexity of the underlying phenomenon and multiplicity of parasitic background effects. In collaboration with researchers in the USA and France, we have performed the first fully quantum simulation of the fundamental characteristics of SHE able to revisit these controversial experimental results. We have succeeded in computing the spin Hall angle in large scale disordered forms of chemically functionalized graphene and have analysed how such quantity scales with the density of chemical defects, their spatial distribution and segregation, temperature and device geometry effects.

    Our results suggest substantial capability of graphene for generating large SHE signals provided an atomic-scale control of chemical modification of graphene is achieved, whereas new device geometry has been proposed to reduce parasitic effects and quantitatively size the maximum charge to current conversion efficiency of such two-dimensional materials.