Bioaccumulation modelling and sensitivity analysis for discovering key players in contaminated food webs: the case study of PCBs in the Adriatic Sea

Modelling bioaccumulation processes at the food web level is the main step to analyse the effects of pollutants at the global ecosystem level. A crucial question is understanding which species play a key role in the trophic transfer of contaminants to disclose the contribution of feeding linkages and the importance of trophic dependencies in bioaccumulation dynamics. In this work we present a computational framework to model the bioaccumulation of organic chemicals in aquatic food webs, and to discover key species in polluted ecosystems. As a result, we reconstruct the first PCBs bioaccumulation model of the Adriatic food web, estimated after an extensive review of published concentration data. We define a novel index aimed to identify the key species in contaminated networks, Sensitivity Centrality, and based on sensitivity analysis. The index is computed from a dynamic ODE model parametrised from the estimated PCBs bioaccumulation model and compared with a set of established trophic indices of centrality. Results evidence the occurrence of PCBs biomagnification in the Adriatic food web, and highlight the dependence of bioaccumulation on trophic dynamics and external factors like fishing activity. We demonstrate the effectiveness of the introduced Sensitivity Centrality in identifying the set of species with the highest impact on the total contaminant flows and on the efficiency of contaminant transport within the food web

Honduras: la crisis de la democracia

Los procesos destituyentes actuales son diferentes a los que experimentó América Latina durante la década del ´70, ´80 y ´90. Están atravesados por coyunturas históricas distintas, otros actores, otros procesos internacionales, por esto requieren de otra mirada. Podemos afirmar que no todo proceso destituyente supone las mismas causas y las mismas consecuencias. Sin embargo, elementos de continuidad pueden ser observados dentro de un contexto que se presenta en otro clima de época. Asistimos a la tercera ola democratizadora aquella que enunciaba (Huntington, 1994), aquél proceso que comenzó a principios de la década del 70. Para comprender algunos de los sucesos actuales referidos a la tercera ola, que se supone de transición y consolidación de las democracias surgidas en América Latina, será necesario referirnos en primer lugar a la forma en que estos acontecimientos son nombrados por quienes se han ocupado de analizarlos. La utilización de los conceptos deviene en muy importante cuando se trata de describir un acontecimiento. En las Ciencias Sociales el uso de los conceptos puedeser la clave para comprender, describir y explicar un hecho. El concepto en ciertas circunstancias puede capturar el fenómeno y hacerlo inteligible, en otras, puede crearlo.En efecto, “neogolpismo”, ruptura presidencial, deposición presidencial, golpe de Estado, golpe militar, caída presidencial, fracaso presidencial, golpe constitucional, interrupción presidencial, golpe cívico-militar son algunos de los conceptos que se han utilizado para describir una realidad pasada y presente en algunos países latinoamericanos con procesos democráticos en marcha de larga data. Lo viejo y lo nuevo. Factores que demuestran que aún cuando la consolidación de la democracia es un hecho que se reconoce o que en definitiva se espera, resabios del pasado aún acompañan estos procesos en plena tercera ola de democratización.Nowadays, the removal of executive powers are different to the ones Latin America experimented during the 70’s, 80’s and 90’s decade. At the time, this processes faced different historical conjunctures, other actors and international processes. For this purpose, they require another look. It can be stated that not every president’s removal or deposition process has the same causes and consequences. Thus, we can observe certain continuities within a context that presents another world stage; for instance, the third wave of democratization announced by Huntington (1994), a process that started at the beginning of the 70s. In order to understand some of these actual phenomena referred to the third wave (mainly transitional and established democracies in LatinAmerica) it will be necessary to study how this events or situations are named by thosewho analyze them. Therefore, in the Social Sciences the use of concepts can be a key to understand, describe and explain a fact. Besides, terms like presidential deposition, state coup, military coup, presidential fall, presidential failure, constitutional coup, presidential interruption, military – civic coup are some of the concepts that have been used to describe the past and present state of some Latin-American democracies

Una reconstrucción de época: hechos, ideas, corrientes de pensamiento y sustratos de los debates de entreguerras (1918/1947) vistos desde los dilemas del mundo actual

This research project provides a description of the climate of ideas between the end of World WarI and the beginning of World War II both in Europe and the United States, and its impact on our South American region. The study aims at unveiling the various key issues marking the discussion at the time, starting with those from the previous 1880-1920 period, already researched by other authors, focused on the core idea of civilizing crisis, the social issue, reform or revolution, the tension between capitalism and democracy and debates on how to keep peace. One of the main steps forward we made in 2015 was to introduce in the analysis new highly influential authors of the time as regards the interpretation of the crisis: Peter Sorokin and Karl Polanyi. We also introduced the ongoing trends recovering the political and economic thinking of that time (especially Harold Laski from the British Labor Party, through Jeremy Corsby), and Polanyi for the importance of Piketty in the new critical tradition and constant reference to his work. We broke down the period into three stages: 1st stage to 30 as the effective date of liberal peace by trade, 2nd overturned after the crisis of 30 to the reformulation in terms of utopian realism of Carr and then from 39 to focus on rethinking the structure European and global governance. We undertook a more profound analysis of Laski’s democracy/capitalism tension and the palpable similarity between the crises developed in the region in the interbellum period and the current European crisis within the global context. We undertook a thorough review of Paretto, Mosca and Michels’ study of the theory of elites. Their theoretical propositions related to the contradictions of modern democracy and their questions about the nature, legitimacy and stability of the political power and order, drove our attention to other authors such as Gustav Le Bon, Georges Sorel and Moisei Ostrogorski. We also made a detailed analysis of the cultural climate at the time, especially its artistic expressions in filmmaking, painting, etc. Finally, we began the study of other movements of central ideas of the time, such as the Frankfurt School and the Annales School, and carried outan analysis on the pacifist movements of the period and their correlation with Latin American traditions, especially in the case of the Nobel Peace Prize Award granted to Saavedra Lamas.El proyecto consiste en la descripción del clima de ideas entre el fin de la primera Guerra Mundial y los inicios de la segunda, tanto en Europa como en los EE. UU., y su impacto en nuestra región sudamericana. En este sentido, la investigación se propone descubrir las diferentes claves alrededor de las cuales se daban las discusiones, partiendo de las heredadas del período anterior (1880/1920). Otros autores, al estudiarlas, se han centrado en la idea central de crisis civilizatoria, la cuestión social, la reforma o revolución, la tensión entre capitalismo y democracia y los debates sobre cómo mantener la paz. El principal avance en 2015 fue la incorporación del análisis de nuevos autores de gran influencia en lo relativo a la época, en términos de interpretación de la crisis: Peter Sorokin y Karl Polanyi. Asimismo, hemos incluido la aparición actual de tendencias de recuperación del pensamiento político económico de esa época, particularmente Harold Laski en el Partido Laborista ingles (víaJeremy Corsby) y Polanyi, por la importancia de Piketty en la nueva tradición crítica y la permanente referencia a sus obras. Adicionalmente, avanzamos con la construcción de una periodización en tres etapas: la primera etapa hasta los treinta como aquella de la vigencia de la paz liberal por el comercio; la segunda, volcada tras la crisis de treinta, a la reformulación en términos del realismo utópico de Carry; luego, a partir del treinta y nueve, con un repensar la estructura de gobernanza global y europea. Logramos profundizar el análisis de la tensión democracia/capitalismo en Laski, y la obvia similitud entre las crisis desarrolladas en la región en el período entreguerras y la actual crisis europea en el contexto global. Examinamos detenidamente el estudio de la teoría de las elites en Paretto, Mosca y Michels. Sus proposiciones teóricas respecto de las contradicciones de la democracia moderna; sus preguntas acerca de la naturaleza, legitimidad y estabilidad del poder político y del orden político, nos han llevado a trabajar con otros autores como Gustav Le Bon, Georges Sorel y Moisei Ostrogorski. También nos adentramos en la descripción del clima cultural de la época, especialmente en sus expresiones artísticas en el cine, la pintura, etc. Por último, iniciamos el estudio de otros movimientos de ideas centrales en la época como fueron la escuela de Frankfurt y de los anales, y el análisis de los movimientos pacifistas en la época y su correlación con las tradiciones latinoamericanas, en especial en el caso de la distinción con el premio Nobel de la Paz a Saavedra Lamas

Adenosine receptor agonists: Synthesis and binding affinity of 2-(aryl)alkylthioadenosine derivatives

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Per un curricolo della lingua italiana nella scuola di base

The curriculum of the Italian language needs, nowadays, to face the complexity of the current socio-cultural situation which is deeply characterized by multimodality and multiculturalism, by the technological development and by the effects of globalization. In the contribution the first reflections collected during a qualitative investigation, run by the research group of the department of Education, Cultural Heritage and Tourism of the University of Macerata (Italy), are discussed. The investigation highlights interesting practices, often innovative, but that also show the need to give a new meaning to the concept of curriculum.Teachers show consciousness of the effects on the teaching/learning process of the Italian language caused by the current class context’s complexity. Their reference to class activities and strategies they usually promote to actively involve students are numerous and include the students’ enciclopedia (language-subject) and their multimodal experiences in the interaction with the world (language-world). But, often, such processes are not connected to the curriculum and a step is missing to let teachers acquire the needed fullawareness on the modalities they activate and let them foster triangulation process among the language- subject, the language-world and the languageobject, that is, among processes of immersion in the contexts and ability of distancing and reflection.Il curricolo di Italiano richiede oggi una riflessione profonda. Tale necessità trova origine nei cambiamenti socio-culturali che derivano dalla complessità dell’attuale situazione socio-culturale profondamente connotata dalla multimodalità e dalla multiculturalità, dallo sviluppo tecnologico e dagli effetti della globalizzazione.In questa sede riportiamo alcune riflessioni scaturite da un’indagine di tipo qualitativo sulle strategie messe in atto nelle classi in relazione alla didattica dell’italiano, condotta dal gruppo di ricerca afferente al Dipartimento di Scienze della Formazione, dei Beni Culturali e del Turismo dell’Università degli Studi di Macerata. Dall’indagine emergono pratiche interessanti e spesso innovative, ma fanno emergere anche l’esigenza di attribuire un nuovo significato al concetto di curricolo. La complessità attuale impatta nel processo di insegnamento/ apprendimento della lingua italiana e molti sono gli esempi di percorsi e strategie attuate dal docente in cui lo studente è coinvolto in modo attivo sul piano linguistico, percorsi che includono la sua enciclopedia (lingua-soggetto) e le sue esperienze multimodali nell’interazione con il mondo (lingua-mondo). Manca però quel passaggio che consenta agli insegnanti di acquisire consapevolezza delle modalità attivate e di costruire una coerenza tra tali processi e il curricolo esplicito, favorendo processi di triangolazione tra lingua-soggetto, lingua-mondo e lingua-oggetto, ovvero tra processi di immersione nei contesti e capacità di distanziamento e riflessione

Bioinformatics challenges and potentialities in studying extreme environments

Cold environments are populated by organisms able to contravene deleterious effects of low temperature by diverse adaptive strategies, including the production of ice binding proteins (IBPs) that inhibit the growth of ice crystals inside and outside cells. We describe the properties of such a protein (EfcIBP) identified in the metagenome of an Antarctic biological consortium composed of the ciliate Euplotes focardii and psychrophilic non-cultured bacteria. Recombinant EfcIBP can resist freezing without any conformational damage and is moderately heat stable, with a midpoint temperature of 66.4 degrees C. Tested for its effects on ice, EfcIBP shows an unusual combination of properties not reported in other bacterial IBPs. First, it is one of the best-performing IBPs described to date in the inhibition of ice recrystallization, with effective concentrations in the nanomolar range. Moreover, EfcIBP has thermal hysteresis activity (0.53 degrees C at 50 mu M) and it can stop a crystal from growing when held at a constant temperature within the thermal hysteresis gap. EfcIBP protects purified proteins and bacterial cells from freezing damage when exposed to challenging temperatures. EfcIBP also possesses a potential N-terminal signal sequence for protein transport and a DUF3494 domain that is common to secreted IBPs. These features lead us to hypothesize that the protein is either anchored at the outer cell surface or concentrated around cells to provide survival advantage to the whole cell consortium

Bioremediation in marine ecosystems: a computational study combining ecological modeling and flux balance analysis

The pressure to search effective bioremediation methodologies for contaminated ecosystems has led to the large-scale identification of microbial species and metabolic degradation pathways. However, minor attention has been paid to the study of bioremediation in marine food webs and to the definition of integrated strategies for reducing bioaccumulation in species. We propose a novel computational framework for analysing the multiscale effects of bioremediation at the ecosystem level, based on coupling food web bioaccumulation models and metabolic models of degrading bacteria. The combination of techniques from synthetic biology and ecological network analysis allows the specification of arbitrary scenarios of contaminant removal and the evaluation of strategies based on natural or synthetic microbial strains. In this study, we derive a bioaccumulation model of polychlorinated biphenyls (PCBs) in the Adriatic food web, and we extend a metabolic reconstruction of Pseudomonas putida KT2440 (iJN746) with the aerobic pathway of PCBs degradation. We assess the effectiveness of different bioremediation scenarios in reducing PCBs concentration in species and we study indices of species centrality to measure their importance in the contaminant diffusion via feeding links. The analysis of the Adriatic sea case study suggests that our framework could represent a practical tool in the design of effective remediation strategies, providing at the same time insights into the ecological role of microbial communities within food webs

Erratum to: Molecular modelling study of 2-phenylethynyladenosine (PEAdo) derivatives as highly selective A3 adenosine receptor ligands

A series of 2-phenylethynyladenosine (PEAdo) derivatives substituted in the N6- and 4′position was synthesised and the new derivatives were tested at the four human adenosine receptors stably transfected into Chinese hamster ovary (CHO) cells, using radioligand binding studies (A1, A2A, A3) or adenylyl cyclase activity assay (A2B). Binding studies showed that the presence of a phenyl ethynyl group in the 2 position of adenosine favoured the interaction with A3 receptors, resulting in compounds endowed with high affinity and selectivity for the A3 subtype. Additional substitution of the N6- and 4′position increases both A3 affinity and selectivity. The results showed that the new compounds have a good affinity for the A3 receptor and in particular, the N6-methoxy-2-phenylethynyl-5′N-methylcarboxamidoadenosine, with a Ki at A3 of 1.9 nM and a selectivity A1/A3 and A2A/A3 of 4,800- and 8,600-fold, respectively. Therefore, it is one of the most potent and selective agonists at the human A3 adenosine receptor subtype reported so far. Furthermore, functional assays of inhibition of 10 μM forskolin-stimulated cAMP production via the adenosine A3 receptor revealed that the new trisubstituted adenosine derivatives behave as full agonist of this receptor subtype. Docking analysis of these compounds was performed at a homology model of the human A3 receptor based on the bovine rhodopsin crystal structure as template, and the results are in accordance with the biological data