Suchergebnisse

Los procesos de descomposición sistémica que se viven en Latinoamérica están siendo abordados por una miríada de investigadores, provenientes de las distintas geografías de la región y operadores de una compleja diversidad de marcos epistemológicos que permiten observar preocupaciones en común: procesos de vulnerabilidad social, económica, política, cultura, ambiental, etc. En este sentido, el objetivo de este trabajo fue realizar un mapa conceptual, a partir de los trabajos presentados en el 9° congreso de ALASRU (México D.F., 2014), por medio del análisis de redes sociales, a fin de sintetizar la construcción reticular, en Latinoamérica, del discurso epistemológico de la sociología y el desarrollo rural y poderlo agrupar por región y país. Esto se realizó al analizar dos tipos de coocurrencias: la de palabras en un determinado texto y la de matrices de actores por palabras. Esto permitió descomponer (en términos semánticos), cada uno de los abstracts presentados en dicho congreso, en sus diversos conceptos y conectores gramaticales, lo que arrojó una retícula causal del discurso de cada trabajo.

The photosynthetic cytochrome c550 from the marine diatom Phaeodactylum tricornutum has been purified and characterized. Cytochrome c550 is mostly obtained from the soluble cell extract in relatively large amounts. In addition, the protein appeared to be truncated in the last hydrophobic residues of the C-terminus, both in the soluble cytochrome c550 and in the protein extracted from the membrane fraction, as deduced by mass spectrometry analysis and the comparison with the gene sequence. Interestingly, it has been described that the C-terminus of cytochrome c550 forms a hydrophobic finger involved in the interaction with photosystem II in cyanobacteria. Cytochrome c550 was almost absent in solubilized photosystem II complex samples, in contrast with the PsbO and Psb31 extrinsic subunits, thus suggesting a lower affinity of cytochrome c550 for the photosystem II complex. Under iron-limiting conditions the amount of cytochrome c550 decreases up to about 45% as compared to iron-replete cells, pointing to an iron-regulated synthesis. Oxidized cytochrome c550 has been characterized using continuous wave EPR and pulse techniques, including HYSCORE, and the obtained results have been interpreted in terms of the electrostatic charge distribution in the surroundings of the heme centre. ; This work was supported by the Spanish Ministry of Economy and Competitiveness (BIO2012-35271, BIO2015-64169-P, MAT2011-23861 and CTQ2015-64486-R) the Andalusian Government (PAIDI BIO-022) and the Aragón Government (Grupo consolidado B-18). All these grants were partially financed by the EU FEDER Program. ; Peer reviewed

Los procesos de descomposición sistémica que se viven en Latinoamérica están siendo abordados por una miríada de investigadores, provenientes de las distintas geografías de la región y operadores de una compleja diversidad de marcos epistemológicos que permiten observar preocupaciones en común: procesos de vulnerabilidad social, económica, política, cultura, ambiental, etc. En este sentido, el objetivo de este trabajo fue realizar un mapa conceptual, a partir de los trabajos presentados en el 9° congreso de ALASRU (México D.F., 2014), por medio del análisis de redes sociales, a fin de sintetizar la construcción reticular, en Latinoamérica, del discurso epistemológico de la sociología y el desarrollo rural y poderlo agrupar por región y país. Esto se realizó al analizar dos tipos de coocurrencias: la de palabras en un determinado texto y la de matrices de actores por palabras. Esto permitió descomponer (en términos semánticos), cada uno de los abstracts presentados en dicho congreso, en sus diversos conceptos y conectores gramaticales, lo que arrojó una retícula causal del discurso de cada trabajo. ; Latin America systematic breakdown processes are being approached by a myriad of researchers coming from different places of the region, users of a complex diversity of epistemological frameworks. This allows the observation of common interests: social, economic, political, cultural and environmental vulnerability processes. This work purpose is to develop a conceptual map, from the papers presented in the 9th ALASRU Congress (Mexico City, 2014), through social network analysis, in order to synthetize the reticular construction in Latin America of development and sociology discourse and group it at a "glocal" level, per region, institution and researcher. This was done by analyzing two types of co-occurrences: words from a given text and actor per words. This allowed to restructure (in semantic terms) every and each abstract presented in the Congress, regarding their concepts and grammatical connectors, which generated a casual grid for each paper discourse.

The photosynthetic cytochrome c550 from the marine diatom Phaeodactylum tricornutum has been purified and characterized. Cytochrome c550 is mostly obtained from the soluble cell extract in relatively large amounts. In addition, the protein appeared to be truncated in the last hydrophobic residues of the C-terminus, both in the soluble cytochrome c550 and in the protein extracted from the membrane fraction, as deduced by mass spectrometry analysis and the comparison with the gene sequence. Interestingly, it has been described that the C-terminus of cytochrome c550 forms a hydrophobic finger involved in the interaction with photosystem II in cyanobacteria. Cytochrome c550 was almost absent in solubilized photosystem II complex samples, in contrast with the PsbO and Psb31 extrinsic subunits, thus suggesting a lower affinity of cytochrome c550 for the photosystem II complex. Under iron-limiting conditions the amount of cytochrome c550 decreases up to about 45% as compared to iron-replete cells, pointing to an iron-regulated synthesis. Oxidized cytochrome c550 has been characterized using continuous wave EPR and pulse techniques, including HYSCORE, and the obtained results have been interpreted in terms of the electrostatic charge distribution in the surroundings of the heme centre. ; This work was supported by the Spanish Ministry of Economy and Competitiveness (BIO2012-35271, BIO2015-64169-P, MAT2011-23861 and CTQ2015-64486-R) the Andalusian Government (PAIDI BIO-022) and the Aragón Government (Grupo consolidado B-18). All these grants were partially financed by the EU FEDER Program ; Peer reviewed

In plants, symbiotic hemoglobins act as carriers and buffers of O2 in nodules, whereas nonsymbiotic hemoglobins or phytoglobins (Glbs) are ubiquitous in tissues and may perform multiple, but still poorly defined, functions related to O2 and/or nitric oxide (NO). Here, we have identified a Glb gene of the model legume Medicago truncatula with unique properties. The gene, designated MtGlb1-2, generates four alternative splice forms encoding Glbs with one or two heme domains and 215–351 amino acid residues. This is more than double the size of any hemoglobin from plants or other organisms described so far. A combination of molecular, cellular, biochemical, and biophysical methods was used to characterize these novel proteins. RNA-sequencing showed that the four splice variants are expressed in plant tissues. MtGlb1-2 is transcriptionally activated by hypoxia and its expression is further enhanced by an NO source. The gene is preferentially expressed in the meristems and vascular bundles of roots and nodules. Two of the proteins, bearing one or two hemes, were characterized using mutants in the distal histidines of the hemes. The Glbs are extremely reactive toward the physiological ligands O2, NO, and nitrite. They show very high O2 affinities, NO dioxygenase activity (in the presence of O2), and nitrite reductase (NiR) activity (in the absence of O2) compared with the hemoglobins from vertebrates and other plants. We propose that these Glbs act as either NO scavengers or NO producers depending on the O2 tension in the plant tissue, being involved in the fast and fine tuning of NO concentration in the cytosol in response to sudden changes in O2 availability. ; IV was a Formación de Personal Investigador fellow (BES-2015-073059) and EL is a Ramón y Cajal fellow (RYC2018-023867-I), both from the Spanish State Research Agency-Ministry of Economy, Industry and Competitiveness (MINECO). LM was the recipient of a fellowship partially funded by MIUR-Italy ('Progetto Dipartimenti di Eccellenza 2018-2022' allocated to Department of Chemistry 'Ugo Schiff'). This work was supported by grants AGL2017-85775-R and RTI2018-094623-B-C22 from MINECO, co-funded by the European Regional Development Fund, and by Government of Aragón (group A09_17R).

14 Pags.- 7 Figs. © 2020 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). ; In plants, symbiotic hemoglobins act as carriers and buffers of O2 in nodules, whereas nonsymbiotic hemoglobins or phytoglobins (Glbs) are ubiquitous in tissues and may perform multiple, but still poorly defined, functions related to O2 and/or nitric oxide (NO). Here, we have identified a Glb gene of the model legume Medicago truncatula with unique properties. The gene, designated MtGlb1-2, generates four alternative splice forms encoding Glbs with one or two heme domains and 215–351 amino acid residues. This is more than double the size of any hemoglobin from plants or other organisms described so far. A combination of molecular, cellular, biochemical, and biophysical methods was used to characterize these novel proteins. RNA-sequencing showed that the four splice variants are expressed in plant tissues. MtGlb1-2 is transcriptionally activated by hypoxia and its expression is further enhanced by an NO source. The gene is preferentially expressed in the meristems and vascular bundles of roots and nodules. Two of the proteins, bearing one or two hemes, were characterized using mutants in the distal histidines of the hemes. The Glbs are extremely reactive toward the physiological ligands O2, NO, and nitrite. They show very high O2 affinities, NO dioxygenase activity (in the presence of O2), and nitrite reductase (NiR) activity (in the absence of O2) compared with the hemoglobins from vertebrates and other plants. We propose that these Glbs act as either NO scavengers or NO producers depending on the O2 tension in the plant tissue, being involved in the fast and fine tuning of NO concentration in the cytosol in response to sudden changes in O2 availability. ; IV was a Formación de Personal Investigador fellow (BES- 2015-073059) and EL is a Ramón y Cajal fellow (RYC2018- 023867-I), both from the Spanish State Research Agency-Ministry of Economy, Industry and Competitiveness (MINECO). LM was the recipient of a fellowship partially funded by MIURItaly ("Progetto Dipartimenti di Eccellenza 2018-2022" allocated to Department of Chemistry "Ugo Schiff "). This work was supported by grants AGL2017-85775-R and RTI2018- 094623-B-C22 from MINECO, co-funded by the European Regional Development Fund, and by Government of Aragón (group A09_17R). ; Peer reviewed

The Périgord black truffle is an exclusive culinary delicacy, but its Mediterranean harvests have declined, despite cultivation efforts since the 1970s. The role of long-term irrigation, symbiotic fungus-host interaction, and microbial belowground progression remain poorly understood, because generally too short experimental settings miss the necessary degree of real world complexity and reliable information from truffle orchards is limited. Here, we conduct the first dendrochronological and wood anatomical assessment of 295 holm oaks, which have been growing under different irrigation intensities in the world's largest truffle orchard in Spain. The relationships between different climatic variables (monthly temperature means and precipitation totals) and dendro-parameters (ring width, vessel count and vessel size) of the oak hosts are utilized to disentangle direct and indirect drivers of truffle fruit body production. Irrigation at medium - instead of high - intensity is most beneficial for oak growth. Non-irrigated trees reveal overall lower stem increments. Warmer temperatures from February to April and wetter conditions from May to July enhance host vitality and possibly also its interplay with fungi symbionts via increased fine root production and mycorrhizal colonization. Adequately irrigated Mediterranean orchards may counteract some of the drought-induced natural truffle decline, and help stabilizing rural tourism, regional agriculture and global markets. ; Supported by the WSL-internal DITREC project, the Ernst Göhner Foundation, the ClimFun project of the Norwegian RC (No. 225043), the project AGL2012-40035-C03 (Government of Spain), the project Micosylva+ (Interreg IVB SUDOE SOE3/P2/E533), the Government of Castilla y León, ARAID, the project Xilva (CGL2011-26654, Economy and Competitiveness Ministry), as well as the Operational Program of Education for Competitiveness of Ministry of Education, Youth and Sports of the Czech Republic (No. CZ.1.07/2.3.00/20.0248).