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 24 publications 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
  • Christians living in a Muslim World? Radiocarbon dating of the cemetery over the forum of Pollentia (Mallorca, Balearic Islands) (2017)

    Cau Ontiveros, Miguel Ángel (UB)

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    The Roman city of Pollentia (Alcúdia) is one of the main cities for the study of the Roman period in Spain. Archaeological excavations conducted since 1923 have uncovered the forum, residential quarters, the theater and several necropolises among other remains. The city was founded after the conquest of the Balearics by Quintus Caecilius Metellus in 123 BCE. At the end of the 3rd century CE, a fire destroyed many parts of the city. However, the city continued inhabited through the Vandal (455 CE), Byzantine (534 CE) and the Islamic (902/903 CE) occupations.

    Over the forum area, a large necropolis with more than 300 graves has been excavated since 1980. This cemetery was traditionally dated to the 4th century CE, right after the fire. However, recent excavations have yielded data to question this dating. The types of inhumation graves, the disposition of the bodies and the lack of goods suggest that is a Christian cemetery from the late antique period but dated at least after the 7th century CE.

    In order to obtain an absolute chronology, 14C dating was applied to thirteen bone samples. The results are striking as the dates, ranging mainly from the tenth to the twelfth centuries, fall into the Islamic period (902/903-1229). Muslims were buried in a lateral position with the head towards the East and these graves did not follow Muslim practices. The results are extremely important because provide archaeological evidence for the existence of non-Muslim communities on the island in that period. The graves had typologies and rituals of deposition of the bodies seen in other Christian cemeteries. Were they Christians? If so, were they descendants of the Christian communities that inhabited the city in Late Antiquity or newcomers introduced by the Muslims? Were they Jews? The mystery remains unsolved, but the archaeological identification of a non-Muslim community living in a Muslim world in the Balearics opens new possibilities for the study of these minorities as well as on interaction, tolerance, and co-existence issues, linking in this way past and present.

  • How plants use their own endogneous genetics to limit and compartmentalize beneficial and harmful metals (2017)

    Christou, Paul (UdL)

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    Rice is a staple crop for more than 50% of the world population. Insufficient levels of Fe and Zn in the seed cause deficiency diseases in populations relying on rice as the main source of calories. More than 2 billion people suffer from Fe deficiency anemia and Zn deficiency. Rice grown on contaminated soils also causes cadmium (Cd) toxicity. Therefore, biofortification strategies that enhance Fe and Zn levels in rice endosperm should do so without also encouraging the accumulation of Cd. The maximum levels of Fe and Zn reported in seeds of biofortified rice are well below the Recommended Daily Intake. This suggests an upper limit for Fe and Zn accumulation in the seed. Metal homeostasis acts to prevent the seed becoming overloaded with these metals, but the underlying mechanisms are largely unknown. Nicotianamine (NA) and deoxymugenic acid (DMA) are endogenous metal chelating molecules; increasing the amount of NA or DMA in the plant increases the accumulation of Fe and Zn in the seeds. NA and DMA are synthesized from S-adenosylmethionine in three steps involving nicotianamine synthase (NAS), nicotianamine aminotransferase (NAAT) and DMA synthase (DMAS).

    We generated transgenic rice lines co-expressing NAS and NAAT. These plants accumulated higher levels of NA and DMA and promoted the accumulation of Fe and Zn in seeds Increasing the external supply of Fe affected the uptake of Fe and Zn into the roots and the mobilization of these metals in the aboveground organs, but compensatory mechanisms involving sequestration in leaves have a buffering effect and impose strict limits on the accumulation of metals in the seed. Surprisingly, the preferential retention of Fe and Zn in the seed led to the competitive exclusion of Cd, halving the amount of Cd. This can provide a useful strategy to increase the abundance of metal nutrients in rice while ensuring that toxic metals are exported to the bran. Such strategies could help simultaneously to address micronutrient deficiency and heavy metal toxicity in communities that rely predominantly on cereal-based diets.

  • Photonic Quantum State Transfer between disparate Quantum Nodes (2017)

    de Riedmatten, Hugues (ICFO)

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    Classical information networks such as the internet have revolutionized our way of transmitting and processing data. Now, scientists are trying to build the quantum version of such networks, which hold promise to provide radically new capabilities compared to their classical counterparts. Quantum information networks (consisting of matter quantum nodes and quantum communication channels) could for example enable perfectly secure data transmission, enhanced data processing via distributed quantum computing or advanced clock synchronization applications. While it is generally agreed that photons are the best choice to transmit quantum information, the optimal matter system for building the quantum nodes is still an open question, as each system provides different functionalities. Therefore, the implementation of a hybrid network has been proposed, searching to combine the best capabilities of different material systems.

    In a recent study, published in Nature, ICFO researchers led by ICREA Prof. Hugues de Riedmatten, have achieved an elementary “hybrid” quantum network link and demonstrated for the first time photonic quantum communication between two very distinct quantum nodes placed in different laboratories, using a single photon as information carrier. 

    In their study, the ICFO researchers used two very distinct quantum nodes functioning at different wavelengths: the emitting node was a laser-cooled cloud of Rubidium atoms and the receiving node a crystal doped with Praseodymium ions. They transmitted a qubit from one system to the other, using quantum frequency conversion techniques. The qubit emitted by the cold atomic ensemble was first converted to telecom wavelength, then transmitted to another laboratory via an optical fiber and finally converted to the frequency of the crystal, where it was absorbed and stored.

    The results of the study have shown that two very different quantum systems can be connected and can communicate by means of a single photon. The ability to perform back- and forth-conversion of photonic qubits at the telecom C-band wavelength shows that these systems would be completely compatible with the current telecom networks.

  • Uncovering the underlying mechanisms and whole-brain dynamics of deep brain stimulation for Parkinson's disease. (2017)

    Deco, Gustavo (UPF)

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    Deep brain stimulation, or DBS, has relieved the symptoms of more than 150,000 patients suffering from Parkinson’s disease. However, the functional mechanisms of this treatment have not yet been clarified. Now, thanks to the recent efforts of an international group of researchers, these mechanisms have been published in Scientific Reports.

    The research was designed and conducted by Victor Saenger and Gustavo Deco, of the Center for Brain and Cognition (CBC) at Universitat Pompeu Fabra, and Morten Kringelbach, University of Oxford. The results show that using DBS in the subthalamic nucleus in patients with Parkinson’s disease balances global brain dynamics.

    In the study, the researchers measured brain activity using Functional Magnetic Resonance imaging in ten patients with Parkinson’s disease before and during DBS treatment. Through large scale mathematical models of the brain they have shown the global effects created by such stimulation. Artificial stimulation has also been applied in a simulated brain exposing the brain regions that show greatest treatment efficacy.

    “This method helps us to understand what regions are responsible for changing the brain activity of patients with Parkinson’s disease to the type of activity found in healthy persons. It is the first study to show that DBS treatment, despite being localized, has a global effect”, states Victor Saenger, of the Center for Brain and Cognition at UPF and first author of the article. He adds that “this method allows us also to understand why DBS treatment is so effective. Now we can find more effective stimulation regions without the need for clinical interventions”.

    According to Morten Kringelbach of the University of Oxford, “the perspective of this study shows that we are now able to use computational models of brain activity to simulate the effects of brain stimulation and thus predict the result. In the long term, we hope to use these methods to make personalized interventions to achieve individual benefits”. However, he warns that “it is very important to consider the risks and ethical aspects of using something as invasive as the DBS method”.

  • An epigenetic lesion could be responsible for acute T-cell leukemia (2017)

    Esteller Badosa, Manel (IDIBELL)

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    We discovered how an epigenetic lesion can lead to T-cell acute lymphoblastic leukemia. The article, published in the journal Leukemia, leader in the field of hematology, correlates the lesion with the activation of a powerful oncogen capable of malignizing this type of cells of the immune system. Every two minutes, a person is diagnosed with a blood cell cancer - a leukemia, a lymphoma or a myeloma-, constituting 11% of all the tumors detected every year. T-cell acute lymphoblastic leukemia (T-ALL) creates alterations in the normal development of T lymphocytes, which are the cells responsible for defense against infections. This type of leukemia, which may appear in both children and adults, is characterized by its aggressive behavior. There are certain genetic alterations responsible for up to a third of the cases, but the molecular changes involved in the rest are still unknown.

    Esteller’s group found that in 60% of acute type T leukemias, T lymphocytes present a loss of activity in a gene called NUDT16, whose normal function is to degrade other potentially dangerous genes. The lack of NUDT16 monitoring in these T lymphocytes allows a widely recognized cancer-causing gene, called C-MYC, to act freely and transform these healthy cells into cancer cells. It is interesting to take into account that the NUDT16 gene is not genetically damaged, so it could be reactivated with epigenetic drugs already used in other types of leukemia and lymphoma. It would also be worthwhile to test whether these leukemias, being so dependent on the C-MYC oncogene, would also be more sensitive to drugs targeting this protein. The research was carried out with the clinical collaboration of the Hematology Services of the Santa Creu and Sant Pau Hospital in Barcelona and the Germans Trias i Pujol Hospital in Badalona, ​​as well as the Josep Carreras Leukemia Research Institute.

  • The alternative ways of cancer (2017)

    Eyras Jiménez, Eduardo (UPF)

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    The alternative processing of genomic loci through alternative splicing (AS) to produce multiple transcripts is a prevalent mode of gene expression regulation in multicellular organisms. It is related to essential biological processes and it has been long recognized that disruption of splicing mechanisms can cause disease, including cancer. Cancer arises from genetic and epigenetic alterations that interfere with essential mechanisms of the normal life cycle of cells, such as replication control, DNA repair and cell death. Multiple cancer-related alterations have been described to induce AS changes in tumor transcriptomes, which in turn impact their function and contribute to the pathological properties of tumors. The prevalence of AS in cancer genomes suggests that these alterations may be related to significant functional impacts and may explain some of the observed oncogenic properties. With the aim to address this question, we performed an exhaustive analysis of the functional impacts produced by AS changes in tumors. We described how cancer specific AS changes lead to shorter protein products. As a consequence, transcript isoforms expressed in tumors encode for fewer functional domains, i.e. there is a potential loss of the functional capacities of genes. Protein domains more frequently affected by AS belong to functional families classically affected by somatic mutations in tumors. Additionally, these functional losses are strongly associated to protein-protein interactions and affect partners of classical cancer drivers. Moreover, we observed that protein affecting mutations and splicing changes tend to occur in different patients, suggesting an equivalence between the mutations and splicing changes. Splicing alterations may thus recapitulate similar functional impacts to those observed through genetic alterations, namely protein affecting mutations and copy number alterations, more commonly associated with cancer. Transcriptome data thus shows that alternative splicing has a functional impact similar to other alterations, and may also play a driving role in cancer progression.

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