Highlights

Every year, a committee of experts sits down with a tough job to do: from among all ICREA publications, they must find a handful that stand out from all the others. This is indeed a challenge. The debates are sometimes heated and always difficult but, in the end, a shortlist of  the most outstanding publications of the year is produced. No prize is awarded, and the only additional acknowledge is the honour of being chosen and highlighted by ICREA. Each piece has something unique about it, whether it be a particularly elegant solution, the huge impact it has in the media or the sheer fascination it generates as a truly new idea. For whatever the reason, these are the best of the best and, as such, we are proud to share them here.

LIST OF SCIENTIFIC HIGHLIGHTS

Format: yyyy

  • Not individual genes but the “mutational signatures” of many genes hold the key to better cancer therapies (2022)

    Supek, Fran (IRB Barcelona)

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    Not individual genes but the “mutational signatures” of many genes hold the key to better cancer therapies

    Cancer therapy increasingly relies on a personalised approach, where genetic changes in an individual tumour can be used to determine the best therapeutic strategy. In many cases thus far, these genetic changes included a so-called “driver mutation” that would predict response to a drug. For instance, mutations in the BRAF gene in melanoma predict response to BRAF inhibitor drugs, and amplifications in the HER2 (ERBB2) gene in breast cancer predict response to anti-HER2 therapeutic antibodies.

    However, these examples of successful drug markers are still quite rare. For many mutated driver genes, specific drugs to target them are not available. Moreover, tumours of different patients show high variability in response to drugs and such variability is often not linked to driver gene mutations.

    Our study has found that so-called “mutational signatures” can accurately predict the activity of various drugs applied to cancer cells originating from many types of tumours. These mutational signatures do not originate from driver genes; instead, they reflect a collection of mutations found across the entire genome of a tumour. Such mutational signatures can reflect, for example, that the tumour has difficulties in copying or repairing DNA, which may make it more amenable to therapy.

    We have performed statistical analysis using machine-learning methods, considering jointly cancer cell line genomes, their response to various drug treatments, and their response to CRISPR gene editing experiments. Surprisingly, our statistical analyses revealed that the 'classical' genetic markers such as driver gene mutations or copy-number changes are often less powerful than the mutational signature genetic markers in predicting drug response.

    Interestingly, the cancer cells that bear genomic “scars” (mutational signatures) of previous exposure to mutagenic chemicals tended to be resistant to diverse chemotherapeutic drugs. One possible explanation for this is that cancer cells can switch off some DNA repair systems to better adapt to a treatment by a mutagenic drug, which could permanently covert them into hardy, hypermutating cells resistant to a range of future treatments.

  • Microtubule network organization by molecular motors (2022)

    Surrey, Thomas (CRG)

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    Microtubule network organization by molecular motors

    When cells divide, the genetic material needs to be faithfully segregated. To achieve this, long filaments called microtubules assemble around the chromosomes to pull them to the two new daughter cells. Molecular motors are critical for arranging the microtubules in space and for connecting them into a large dynamic molecular network, called the mitotic spindle. By rebuilding model microtubule networks experimentally from individual components and by using computer simulations, we found out how motors that walk in opposite directions work together to assemble certain parts of the spindle. This work explains how molecular properties of mitotic motors need to be designed in order to enable them to cooperate during the assembly of a higher order network structure that is critical for cell division.

  • Light dressing makes ultracold atoms distinguish left from right (2022)

    Tarruell, Leticia (ICFO)

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    Light dressing makes ultracold atoms distinguish left from right

    The apparently simple problem of the dynamics of electrons confined to a plane with a strong perpendicular magnetic field gives rise to one of the most fascinating phenomena in condensed matter, the fractional quantum Hall effect. This strongly correlated system presents rich physics and has exotic excitations, called anyons, that do not behave like standard particles upon exchange. Besides being interesting for fundamental physics, anyons might also become useful in the future for more robust forms of quantum computing. At low energies, fractional quantum Hall states are elegantly described by a gauge theory similar to those appearing in high energy physics: the Chern-Simons theory.

    In our work, we made significant progress towards engineering anyons in highly controllable quantum systems made of ultracold atoms by realizing for the first time a one-dimensional reduction of the Chern-Simons theory, the chiral BF gauge theory, in a Bose-Einstein condensate.

    The experiment used ultracold potassium-39 atoms in two internal states with very different atomic interactions. By coupling these states using light, we linked the interactions of the atoms to their momentum. This led to a chiral system where the atoms interacted differently for positive or negative momenta, and that corresponded to the chiral BF gauge theory. Chiral interactions were demonstrated through the creation of chiral bright solitons: wavepackets which propagate without dispersion when travelling in one direction, but expand as a normal gas when they move in the opposite direction. These solitons had been predicted almost 25 years ago, but had not been realized before. Finally, we observed that the system self-generated an electric force, making the potassium atoms behave as charged particles despite being in reality neutral. 

    Our result demonstrates that engineering gauge theories with ultracold atoms is under reach, and paves the way towards implementing other models in higher dimensions.

  • The first monograph on Charlemagne's and the Carolingians' European history and memory in Catalan (2022)

    Tischler, Matthias M. (UAB)

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    The first monograph on Charlemagne's and the Carolingians' European history and memory in Catalan

    The history of Charlemagne and the Carolingians is one of the indispensable building blocks of Europe's historical, religious, and cultural identity. Despite all the attempts at appropriations by the great historical European nations such as Germany, France, and Italy, the central figure of the family that created Europe has never escaped a comparative and global vision. This book is the first of its kind in Catalan: a bouquet of flowers on selected topics from the history and memory of Charlemagne, his family, and his religious and cultural achievements that invites the reader to take a chronological and geographical tour from the late antique to the medieval Mediterranean, starting from Italy, the nerve center, then passing through medieval France and the Iberian Peninsula, and stopping at Carolingian Catalonia and the Mediterranean world. The book shows the current trends in the field of international research and integrates Catalonia into the rich panorama of the multiple European identities.

  • Radio pulsation from a gamma-ray binary detected after decades of search (2022)

    Torres, Diego F. (CSIC - ICE)

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    Radio pulsation from a gamma-ray binary detected after decades of search

    Using the largest radio telescope on Earth, the Five-hundred-meter Aperture Spherical radio Telescope (FAST, in China), an international team including ICREA Prof. Diego Torres has discovered radio pulsations from the system LS I 61 303. This is the first evidence for pulsations from this source at any frequency, and proves the existence of a rotating neutron star in this system, something that was debated for decades.

    LS I 61 303 is a rare system, one of the few known gamma-ray binaries. These systems emit most of their luminosity in photons with very high energies. They are stellar systems formed by a massive star and a compact object, that can be either a black hole or a neutron star. To know for sure what the compact object is has implications for understanding the multifrequency emission and the evolutionary path of gamma-ray binaries, and how to relate them to other classes. In this case, LS I 61 303 has also shown super-orbital variability and magnetar-like flares.

    Torres' group have carried out many deep searches for pulsations in X-rays, hard X-rays, and GeV gamma-rays before actually finding them in radio frequencies. It was a difficult task: not only they were trying to detect a pulsar that is not particularly bright, but, similarly to other pulsars, one for which pulsations are not permanent.

    Torres is particularly concerned with the period actually found also from a theoretical perspective. The period of the pulsar, 0.26 s, is right at the predicted range of a multi-frequency model he did a decade ago (Torres et al. 2012, and A. Papitto,Torres, & Rea 2012, both published in The Astrophysical Journal). In this model, the system transitions between two states along the orbit, according to the mass pressure in the vicinity, explaining long-term multi-frequency recurrencies as well. The current period measurement brings increased interest to this possibility.

  • Sugar taxation to simultaneously combat climate change, deforestation and health risks (2022)

    van den Bergh, Jeroen (UAB)

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    Sugar taxation to simultaneously combat climate change, deforestation and health risks

    The study highlights that sugar taxation has the potential to meet apparently competing objectives. The reason is that sugar is one of the worst foods to eat from a health perspective while especially sugarcane has great potential for biofuel production.

    The starting point is that the EU implements a sugar tax to reduce EU-wide sugar use, both in consumption and production, such as of beverages. Three scenarios are then explored, namely the EU reforesting its existing sugar cropland, the EU switching its sugar beet crops to ethanol production, and the EU exporting its excess sugar production to meet worldwide demand while another main exporter, namely Brazil, switches its sugarcane crops from sugar to ethanol production.

    As visualized in the figure, calculations indicate that emissions could fall by 20.9–54.3 MtCO2e per year under the latter scenario. These savings would be double to four times those from the other scenarios.

    In line with these findings, the study recommends that the EU and Brazil strike an agreement in which the EU concentrates on sugar production from sugar beet for the global sugar market while Brazil focuses on producing ethanol from sugarcane. This would provide the greatest environmental benefits to society. Sugarcane ethanol production has already proved to be an economically viable alternative to sugar in Brazil and is more efficient than ethanol production from sugar beet. An additional advantage is that the economic impact on farmers in both the EU and Brazil would be minimal, limiting potential social resistance against the plan.

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