The Mont Collon mafic complex (Austroalpine Dent Blanche nappe) : permian evolution of the Western European mantle

Résumé: Le complexe du Mont Collon (nappe de la Dent Blanche, Austroalpin) est l'un des exemples les mieux préservés du magmatisme mafique permien des Alpes occidentales. Il est composé d'affleurements discontinus et d'une stratification magmatique en son centre (Dents de Bertol) et est composé à 95% de roches mafiques cumulatives (gabbros à olivine et/ou cpx, anorthositiques, troctolites, wehrlites et wehrlites à plagioclase) et localement de quelques gabbros pegmatitiques. Ces faciès sont recoupés par de nombreux filons acides (aphtes, pegmatites quartziques, microgranodiorites et filons anorthositiques) et mafiques tardifs (dikes mélanocrates riches en Fe et Ti). Les calculs thermométriques (équilibre olivine-augite) montrent des températures de 1070-1120 ± 6°C, tandis que le thermomètre amphibole-plagioclase indique une température de 740 ± 40°C à 0.5 GPa pour les amphiboles magmatiques tardives. La geobarométrie sur pyroxène donne des pressions moyennes de 0.3-0.6 GPa, indiquant un emplacement dans la croûte moyenne. De plus, les températures obtenues sur des amphiboles coronitiques indiquent des températures de l'ordre de 700 ± 40°C confirmant que les réactions coronitiques apparaissent dans des conditions subsolidus. Les âges concordants U/Pb sur zircons de 284.2 ± 0.6 et 282.9 ± 0.6 Ma obtenus sur un gabbro pegmatitique et une pegmatitique quartzique, sont interprétés comme des âges de cristallisation. Les datations 40Ar/39Ar sur amphiboles des filons mélanocrates donnent un âge plateau de 260.2 ± 0.7 Ma, qui est probablement très proche de l'âge de cristallisation. Ainsi, cet age 40Ar/39Ar indique un second évènement magmatique au sein du complexe. Les compositions des roches totales en éléments majeurs et traces montrent peu de variations, ainsi que le Mg# (75-80). Les éléments traces enregistrent le caractère cumulatif des roches (anomalie positive en Eu) et révèlent des anomalies négatives systématiques en Nb, Ta, Zr, Hf et Ti dans les faciès basiques. Le manque de corrélation entre éléments majeurs et traces est caractéristique d'un processus de cristallisation in situ impliquant une quantité variable de liquide interstitiel (L) entre les phases cumulus. Les distributions des éléments traces dans les minéraux sont homogènes, indiquant une rééquilibration .subsolidus entre cristaux et liquide interstitiel. Un modèle quantitatif basé sur les équations de cristallisation in situ de Langmuir reproduisent correctement les concentrations en terres rares légères des minéraux cumulatifs montrant la présence de 0 à 35% de liquide interstitiel L pour des degrés de différenciation F de 0 à 45%, par rapport au faciès les moins évolués du complexe. En outre, les valeurs de L sont bien corrélées avec les proportions modales d'amphibole interstitielle et les concentrations en éléments incompatibles des roches (Zr, Nb). Le liquide parental calculé des cumulats du Mont Collon est caractérisé par un enrichissement relatif en terres rares légères et Th, un appauvrissement en terres rares lourdes typique d'une affinité transitionnelle (T-MORB) et une forte anomalie négative en Nb-Ta. Les roches cumulatives montrent des compositions isotopiques en Nd-Sr proches de la terre globale silicatée (BSE), soit 0.6<εNdi<+3.2, 0.7045<87Sr/86Sri<0.7056. Les rapports initiaux en Pb indiquent une source dans le manteau enrichi subcontinental lithosphérique, préalablement contaminé par des sédiments océaniques. Les dikes mélanocrates Fe-Ti sont représentatifs de liquides et ont des spectres de terres rares enrichis, une anomalie positive en Nb-Ta et des εNdi de +7, des 87Sr/86Sri de 0.703 et des rapports initiaux en Pb, similaires à ceux des basaltes d'île océanique, indiquant une source asthénosphérique modérément appauvrie. Ainsi, la fusion partielle du manteau lithosphérique subcontinental est induite par l'amincissement post-orogénique et la remontée de l'asthénosphère. Les filons mélanocrates proviennent, après délamination du manteau lithosphérique, de la fusion de l'asthénosphère. Abstract The early Permian Mont Collon mafic complex (Dent Blanche nappe, Austroalpine nappe system) is one of the best preserved examples of the Permian mafic magmatism in the Western Alps. It is composed of discontinuous exposures and a well-preserved magmatic layering (the Dents de Bertol cliff) crops out in the center part of the complex. It mainly consists of cumulative mafic rocks, which represent 95 vol-% of the mafic complex (ol- and cpx-bearing gabbros and rare anorthositic layers, troctolites, wehrlites and plagioclase-wehrlites) and locally pegmatitic gabbros. All these facies are crosscut by widespread acidic (aplites, quartz-rich pegmatites, microgranodiorites) and late mafic Fe-Ti melanocratic dikes. Olivine-augite thermometric calculations yield a range of 1070-1120 ± 6°C, while amphibole-plagioclase thermometer yields a temperature of 740 ± 40°C at 0.5 GPa. Pyroxene geobarometry points to a pressure of 0.3-0.6 GPa, indicating a middle crustal level of emplacement. Moreover, temperature calculations on the Mont Conon coronitic amphiboles indicate temperatures of 700 ± 40°C, close to those calculated for magmatic amphiboles. These temperatures confirm that coronitic reactions occurred at subsolidus conditions. ID-TIMS U/Pb zircon ages of 284.2 ± 0.6 and 282.9 ± 0.6 Ma obtained on a pegmatitic gabbro and a quartz-pegmatitic dike, respectively, were interpreted as the crystallization ages of these rocks. 40Ar/39Ar dating on amphiboles from Fe-Ti melanocratic dikes yields a plateau age of 260.2 ± 0.7 Ma, which is probably very close to the crystallization age. Consequently, this 40Ar/P39Ar age indicates a second magmatic event. Whole-rock major- and trace-element compositions show little variation across the whole intrusion and Mg-number stays within a narrow range (75-80). Trace-element concentrations record the cumulative nature of the rocks (e.g. positive Eu anomaly) and reveal systematic Nb, Ta, Zr, Hf and Ti negative anomalies for all basic facies. The lack of correlation between major and trace elements is characteristic of an in situ crystallization process involving variable amounts of interstitial liquid (L) trapped between the cumulus mineral phases. LA-ICPMS measurements show that trace-element distributions in minerals are homogeneous, pointing to subsolidus re-equilibration between crystals and interstitial melts. A quantitative modeling based on Langmuir's in situ crystallization equation successfully reproduced the Rare Earth Element (REE) concentrations in cumulitic minerals. The calculated amounts of interstitial liquid L vary between 0 and 35% for degrees of differentiation F of 0 to 45%, relative to the least evolved facies of the intrusion. Furthermore, L values are well correlated with the modal proportions of interstitial amphibole and whole-rock incompatible trace-element concentrations (e.g. Zr, Nb) of the tested samples. The calculated parental melt of the Mont Collon cumulates is characterized by a relative enrichment in Light REE and Th, a depletion in Heavy REE, typical of a transitional affinity (T-MORB), and strong negative Nb-Ta anomaly. Cumulative rocks display Nd-Sr isotopic compositions close to the BSE (-0.6 < εNdi < +3.2, 0.7045 < 87Sr/86Sri < 0.7056). Initial Pb ratios point to an origin from the melting of an enriched subcontinental lithospheric mantle source, previously contaminated at the source by oceanic sediments. The contrasted alkaline Fe-Ti melanocratic dikes are representative of liquids. They display enriched fractionated REE patterns, a positive Nb-Ta anomaly and εNdi of +7, 87Sr/86Sri of 0.703 and initial Pb ratios, all reminiscent of Ocean Island Basalt-type rocks, pointing to a moderately

Contribution to the geology of Thailand and implications for the geodynamic evolution of Southeast Asia

Abstract The purpose of this study is to unravel the geodynamic evolution of Thailand and, from that, to extend the interpretation to the rest of Southeast Asia. The methodology was based in a first time on fieldwork in Northern Thailand and Southernmost Myanmar, using a multidisciplinary approach, and then on the compilation and re-interpretation, in a plate tectonics point of view, of existing data about the whole Southeast Asia. The main results concern the Nan-Uttaradit suture, the Chiang Mai Volcanic Belt and the proposition of a new location for the Palaeotethys suture. This led to the establishment of a new plate tectonic model for the geodynamic evolution of Southeast Asia, implying the existence new terranes (Orang Laut and the redefinition of Shan-Thai) and the role of the Palaeopacific Ocean in the tectonic development of the area. The model proposed here considers the Palaeotethys suture as located along the Tertiary Mae Yuam Fault, which represents the divide between the Cimmerian Sibumasu terrane and the Indochina-derived Shan-Thai block. The term Shan-Thai, previously used to define the Cimmerian area (when the Palaeotethys suture was thought to represented by the Nan-Uttaradit suture), was redefined here by keeping its geographical location within the Shan States of Myanmar and Central-Northern Thailand, but attributing it an East Asian Origin. Its detachment from Indochina was the result of the Early Permian opening of the Nan basin. The Nan basin closed during the Middle Triassic, before the deposition of Carnian-Norian molasse. The modalities of the closure of the basin imply a first phase of Middle Permian obduction, followed by final eastwards subduction. The Chiang Mai Volcanic Belt consists of scattered basaltic rocks erupted at least during the Viséan in an extensional continental intraplate setting, on the Shan-Thai part of the Indochina block. The Viséan age was established by the dating of limestone stratigraphically overlying the basalts. In several localities of the East Asian Continent, coeval extensional features occur, possibly implying one or more Early Carboniferous extensional events at a regional scale. These events occurred either due to the presence of a mantle plume or to the roll-back of the Palaeopacific Ocean, subducting beneath Indochina and South China, or both. The Palaeopacific Ocean is responsible, during the Early Permian, for the opening of the Song Ma and Poko back-arcs (Vietnam) with the consequent detachment of the Orang Laut Terranes (Eastern Vietnam, West Sumatra, Kalimantan, Palawan, Taiwan). The Late Triassic/Early Jurassic closure of the Eastern Palaeotethys is considered as having taken place by subduction beneath its southern margin (Gondwana), due to the absence of Late Palaeozoic arc magmatism on its northern (Indochinese) margin and the presence of volcanism on the Cimmerian blocks (Mergui, Lhasa). Résumé Le but de cette étude est d'éclaircir l'évolution géodynamique de la Thaïlande et, à partir de cela, d'étendre l'interprétation au reste de l'Asie du Sud-Est. La méthodologie utilisée est basée dans un premier temps sur du travail de terrain en Thaïlande du nord et dans l'extrême sud du Myanmar, en se basant sur une approche pluridisciplinaire. Dans un deuxième temps, la compilation et la réinterprétation de données préexistantes sur l'Asie du Sud-est la été faite, dans une optique basée sur la tectonique des plaques. Les principaux résultats de ce travail concernent la suture de Nan-Uttaradit, la « Chiang Mai Volcanic Belt» et la proposition d'une nouvelle localité pour la suture de la Paléotethys. Ceci a conduit à l'établissement d'un nouveau modèle pour l'évolution géodynamique de l'Asie du Sud-est, impliquant l'existence de nouveaux terranes (Orang Laut et Shan-Thai redéfini) et le rôle joué par le Paléopacifique dans le développement tectonique de la région. Le modèle présenté ici considère que la suture de la Paléotethys est située le long de la faille Tertiaire de Mae Yuam, qui représente la séparation entre le terrain Cimmérien de Sibumasu et le bloc de Shan-Thai, d'origine Indochinoise. Le terme Shan-Thai, anciennement utilise pour définir le bloc Cimmérien (quand la suture de la Paléotethys était considérée être représentée par la suture de Nan-Uttaradit), a été redéfini ici en maintenant sa localisation géographique dans les états Shan du Myanmar et la Thaïlande nord-centrale, mais en lui attribuant une origine Est Asiatique. Son détachement de l'Indochine est le résultat de l'ouverture du basin de Nan au Permien Inférieur. Le basin de Nan s'est fermé pendant le Trias Moyen, avant le dépôt de molasse Carnienne-Norienne. Les modalités de fermeture du basin invoquent une première phase d'obduction au Permien Moyen, suivie par une subduction finale vers l'est. La "Chiang Mai Volcanic Belt" consiste en des basaltes éparpillés qui ont mis en place au moins pendant le Viséen dans un contexte extensif intraplaque continental sur la partie de l'Indochine correspondant au bloc de Shan-Thai. L'âge Viséen a été établi sur la base de la datation de calcaires qui surmontent stratigraphiquement les basaltes. Dans plusieurs localités du continent Est Asiatique, des preuves d'extension plus ou moins contemporaines ont été retrouvées, ce qui implique l'existence d'une ou plusieurs phases d'extension au Carbonifère Inférieur a une échelle régionale. Ces événements sont attribués soit à la présence d'un plume mantellique, ou au rollback du Paléopacifique, qui subductait sous l'Indochine et la Chine Sud, soit les deux. Pendant le Permien inférieur, le Paléopacifique est responsable pour l'ouverture des basins d'arrière arc de Song Ma et Poko (Vietnam), induisant le détachement des Orang Laut Terranes (Est Vietnam, Ouest Sumatra, Kalimantan, Palawan, Taiwan). La fermeture de la Paléotethys Orientale au Trias Supérieur/Jurassique Inférieur est considérée avoir eu lieu par subduction sous sa marge méridionale (Gondwana), à cause de l'absence de magmatisme d'arc sur sa marge nord (Indochinoise) et de la présence de volcanisme sur les blocs Cimmériens de Lhassa et Sibumasu (Mergui). Résumé large public L'histoire géologique de l'Asie du Sud-est depuis environ 430 millions d'années a été déterminée par les collisions successives de plusieurs continents les uns avec les autres. Il y a environ 430 millions d'années, au Silurien, un grand continent appelé Gondwana, a commencé à se «déchirer» sous l'effet des contraintes tectoniques qui le tiraient. Cette extension a provoqué la rupture du continent et l'ouverture d'un grand océan, appelé Paléotethys, éloignant les deux parties désormais séparées. C'est ainsi que le continent Est Asiatique, composé d'une partie de la Chine actuelle, de la Thaïlande, du Myanmar, de Sumatra, du Vietnam et de Bornéo a été entraîné avec le bord (marge) nord de la Paléotethys, qui s'ouvrait petit à petit. Durant le Carbonifère Supérieur, il y a environ 300 millions d'années, le sud du Gondwana subissait une glaciation, comme en témoigne le dépôt de sédiments glaciaires dans les couches de cet âge. Au même moment le continent Est Asiatique se trouvait à des latitudes tropicales ou équatoriales, ce qui permettait le dépôt de calcaires contenant différents fossiles de foraminifères d'eau chaude et de coraux. Durant le Permien Inférieur, il y a environ 295 millions d'années, la Paléotethys Orientale, qui était un relativement vieil océan avec une croûte froide et lourde, se refermait. La croûte océanique a commencé à s'enfoncer, au sud, sous le Gondwana. C'est ce que l'on appelle la subduction. Ainsi, le Gondwana s'est retrouvé en position de plaque supérieure, par rapport à la Paléotethys qui, elle, était en plaque inférieure. La plaque inférieure en subductant a commencé à reculer. Comme elle ne pouvait pas se désolidariser de la plaque supérieure, en reculant elle l'a tirée. C'est le phénomène du «roll-back ». Cette traction a eu pour effet de déchirer une nouvelle fois le Gondwana, ce qui a résulté en la création d'un nouvel Océan, la Neotethys. Cet Océan en s'ouvrant a déplacé une longue bande continentale que l'on appelle les blocs Cimmériens. La Paléotethys était donc en train de se fermer, la Neotethys de s'ouvrir, et entre deux les blocs Cimmériens se rapprochaient du Continent Est Asiatique. Pendant ce temps, le continent Est Asiatique était aussi soumis à des tensions tectoniques. L'Océan Paléopacifique, à l'est de celui-ci, était aussi en train de subducter. Cette subduction, par roll-back, a déchiré le continent en détachant une ligne de microcontinents appelés ici « Orang Laut Terranes », séparés du continent par deux océans d'arrière arc : Song Ma et Poko. Ceux-ci sont composés de Taiwan, Palawan, Bornéo ouest, Vietnam oriental, et la partie occidentale de Sumatra. Un autre Océan s'est ouvert pratiquement au même moment dans le continent Est Asiatique : l'Océan de Nan qui, en s'ouvrant, a détaché un microcontinent appelé Shan-Thai. La fermeture de l'Océan de Nan, il y a environ 230 millions d'années a resolidarisé Shan-Thai et le continent Est Asiatique et la trace de cet événement est aujourd'hui enregistrée dans la suture (la cicatrice de l'Océan) de Nan-Uttaradit. La cause de l'ouverture de l'Océan de Nan peut soit être due à la subduction du Paléopacifique, soit aux fait que la subduction de la Paléotethys tirait le continent Est Asiatique par le phénomène du « slab-pull », soit aux deux. La subduction du Paléopacifique avait déjà crée de l'extension dans le continent Est Asiatique durant le Carbonifère Inférieur (il y a environ 340-350 millions d'années) en créant des bassins et du volcanisme, aujourd'hui enregistré en différents endroits du continent, dont la ceinture volcanique de Chiang Mai, étudiée ici. A la fin du Trias, la Paléotethys se refermait complètement, et le bloc Cimmérien de Sibumasu entrait en collision avec le continent Est Asiatique. Comme c'est souvent le cas avec les grands océans, il n'y a pas de suture proprement dite, avec des fragments de croûte océanique, pour témoigner de cet évènement. Celui-ci est visible grâce à la différence entre les sédiments du Carbonifère Supérieur et du Permieñ Inférieur de chaque domaine : dans le domaine Cimmérien ils sont de type glaciaire alors que dans le continent Est Asiatique ils témoignent d'un climat tropical. Les océans de Song Ma et Poko se sont aussi refermés au Trias, mais eux ont laissé des sutures visibles

Population demography and the evolution of helping behaviors.

Limited dispersal may favor the evolution of helping behaviors between relatives as it increases their relatedness, and it may inhibit such evolution as it increases local competition between these relatives. Here, we explore one way out of this dilemma: if the helping behavior allows groups to expand in size, then the kin-competition pressure opposing its evolution can be greatly reduced. We explore the effects of two kinds of stochasticity allowing for such deme expansion. First, we study the evolution of helping under environmental stochasticity that may induce complete patch extinction. Helping evolves if it results in a decrease in the probability of extinction or if it enhances the rate of patch recolonization through propagules formed by fission of nonextinct groups. This mode of dispersal is indeed commonly found in social species. Second, we consider the evolution of helping in the presence of demographic stochasticity. When fecundity is below its value maximizing deme size (undersaturation), helping evolves, but under stringent conditions unless positive density dependence (Allee effect) interferes with demographic stochasticity. When fecundity is above its value maximizing deme size (oversaturation), helping may also evolve, but only if it reduces negative density-dependent competition.

Effects of selection and drift on G matrix evolution in a heterogeneous environment: a multivariate Qst-Fst Test with the freshwater snail Galba truncatula.

Unraveling the effect of selection vs. drift on the evolution of quantitative traits is commonly achieved by one of two methods. Either one contrasts population differentiation estimates for genetic markers and quantitative traits (the Q(st)-F(st) contrast) or multivariate methods are used to study the covariance between sets of traits. In particular, many studies have focused on the genetic variance-covariance matrix (the G matrix). However, both drift and selection can cause changes in G. To understand their joint effects, we recently combined the two methods into a single test (accompanying article by Martin et al.), which we apply here to a network of 16 natural populations of the freshwater snail Galba truncatula. Using this new neutrality test, extended to hierarchical population structures, we studied the multivariate equivalent of the Q(st)-F(st) contrast for several life-history traits of G. truncatula. We found strong evidence of selection acting on multivariate phenotypes. Selection was homogeneous among populations within each habitat and heterogeneous between habitats. We found that the G matrices were relatively stable within each habitat, with proportionality between the among-populations (D) and the within-populations (G) covariance matrices. The effect of habitat heterogeneity is to break this proportionality because of selection for habitat-dependent optima. Individual-based simulations mimicking our empirical system confirmed that these patterns are expected under the selective regime inferred. We show that homogenizing selection can mimic some effect of drift on the G matrix (G and D almost proportional), but that incorporating information from molecular markers (multivariate Q(st)-F(st)) allows disentangling the two effects.

Evolutionary switch and genetic convergence on rbcL following the evolution of C4 photosynthesis.

Rubisco is responsible for the fixation of CO2 into organic compounds through photosynthesis and thus has a great agronomic importance. It is well established that this enzyme suffers from a slow catalysis, and its low specificity results into photorespiration, which is considered as an energy waste for the plant. However, natural variations exist, and some Rubisco lineages, such as in C4 plants, exhibit higher catalytic efficiencies coupled to lower specificities. These C4 kinetics could have evolved as an adaptation to the higher CO2 concentration present in C4 photosynthetic cells. In this study, using phylogenetic analyses on a large data set of C3 and C4 monocots, we showed that the rbcL gene, which encodes the large subunit of Rubisco, evolved under positive selection in independent C4 lineages. This confirms that selective pressures on Rubisco have been switched in C4 plants by the high CO2 environment prevailing in their photosynthetic cells. Eight rbcL codons evolving under positive selection in C4 clades were involved in parallel changes among the 23 independent monocot C4 lineages included in this study. These amino acids are potentially responsible for the C4 kinetics, and their identification opens new roads for human-directed Rubisco engineering. The introgression of C4-like high-efficiency Rubisco would strongly enhance C3 crop yields in the future CO2-enriched atmosphere.

Rapid evolution of cancer/testis genes on the X chromosome.

BACKGROUND: Cancer/testis (CT) genes are normally expressed only in germ cells, but can be activated in the cancer state. This unusual property, together with the finding that many CT proteins elicit an antigenic response in cancer patients, has established a role for this class of genes as targets in immunotherapy regimes. Many families of CT genes have been identified in the human genome, but their biological function for the most part remains unclear. While it has been shown that some CT genes are under diversifying selection, this question has not been addressed before for the class as a whole. RESULTS: To shed more light on this interesting group of genes, we exploited the generation of a draft chimpanzee (Pan troglodytes) genomic sequence to examine CT genes in an organism that is closely related to human, and generated a high-quality, manually curated set of human:chimpanzee CT gene alignments. We find that the chimpanzee genome contains homologues to most of the human CT families, and that the genes are located on the same chromosome and at a similar copy number to those in human. Comparison of putative human:chimpanzee orthologues indicates that CT genes located on chromosome X are diverging faster and are undergoing stronger diversifying selection than those on the autosomes or than a set of control genes on either chromosome X or autosomes. CONCLUSION: Given their high level of diversifying selection, we suggest that CT genes are primarily responsible for the observed rapid evolution of protein-coding genes on the X chromosome.

Five-year evolution of drug prescribing in a university adult intensive care unit

Introduction: Drug prescription is difficult in ICUs as prescribers are many, drugs expensive and decisions complex. In our ICU, specialist clinicians (SC) are entitled to prescribe a list of specific drugs, negotiated with intensive care physicians (ICP). The objective of this investigation was to assess the 5-year evolution of quantity and costs of drug prescription in our adult ICU and identify the relative costs generated by ICP or SC. Methods: Quantities and costs of drugs delivered on a quarterly basis to the adult ICU of our hospital between 2004 and 2008 were extracted from the pharmacy database by ATC code, an international five-level classification system. Within each ATC first level, drugs with either high level of consumption, high costs or large variations in quantities and costs were singled out and split by type of prescriber, ICP or SC. Cost figures used were drug purchase prices by the hospital pharmacy. Results: Over the 5-year period, both quantities and costs of drugs increased, following a nonsteady, nonparallel pattern. Four ATC codes accounted for 80% of both quantities and costs, with ATC code B (blood and haematopoietic organs) amounting to 63% in quantities and 41% in costs, followed by ATC code J (systemic anti-infective, 20% of the costs), ATC code N (nervous system, 11% of the costs) and ATC code C (cardiovascular system, 8% of the costs). Prescription by SC amounted to 1% in drug quantities, but 19% in drug costs. The rate of increase in quantities and costs was seven times larger for ICP than for SC (Figure 1 overleaf ). Some peak values in costs and quantities were related to a very limited number of patients. Conclusions: A 5-year increase in quantities and costs of drug prescription in an ICU is a matter of concern. Rather unexpectedly, total costs and cost increases were generated mainly by ICP. A careful follow-up is necessary to try influencing this evolution through an institutional policy co-opted by all professional categories involved in the process.

Subcellular fractionation of stored red blood cells reveals a compartment-based protein carbonylation evolution.

During blood banking, erythrocytes undergo storage lesions, altering or degrading their metabolism, rheological properties, and protein content. Carbonylation is a hallmark of protein oxidative lesions, thus of red blood cell oxidative stress. In order to improve global erythrocyte protein carbonylation assessment, subcellular fractionation has been established, allowing us to work on four different protein populations, namely soluble hemoglobin, hemoglobin-depleted soluble fraction, integral membrane and cytoskeleton membrane protein fractions. Carbonylation in erythrocyte-derived microparticles has also been investigated. Carbonylated proteins were derivatized with 2,4-dinitrophenylhydrazine (2,4-DNPH) and quantified by western blot analyses. In particular, carbonylation in the cytoskeletal membrane fraction increased remarkably between day 29 and day 43 (P<0.01). Moreover, protein carbonylation within microparticles released during storage showed a two-fold increase along the storage period (P<0.01). As a result, carbonylation of cytoplasmic and membrane protein fractions differs along storage, and the present study allows explaining two distinct steps in global erythrocyte protein carbonylation evolution during blood banking. This article is part of a Special Issue entitled: Integrated omics.

Evaluation of cumulative PCB exposure estimated by a job exposure matrix versus PCB serum concentrations.

Although polychlorinated biphenyls (PCBs) have been banned in many countries for more than three decades, exposures to PCBs continue to be of concern due to their long half-lives and carcinogenic effects. In National Institute for Occupational Safety and Health studies, we are using semiquantitative plant-specific job exposure matrices (JEMs) to estimate historical PCB exposures for workers (n = 24,865) exposed to PCBs from 1938 to 1978 at three capacitor manufacturing plants. A subcohort of these workers (n = 410) employed in two of these plants had serum PCB concentrations measured at up to four times between 1976 and 1989. Our objectives were to evaluate the strength of association between an individual worker's measured serum PCB levels and the same worker's cumulative exposure estimated through 1977 with the (1) JEM and (2) duration of employment, and to calculate the explained variance the JEM provides for serum PCB levels using (3) simple linear regression. Consistent strong and statistically significant associations were observed between the cumulative exposures estimated with the JEM and serum PCB concentrations for all years. The strength of association between duration of employment and serum PCBs was good for highly chlorinated (Aroclor 1254/HPCB) but not less chlorinated (Aroclor 1242/LPCB) PCBs. In the simple regression models, cumulative occupational exposure estimated using the JEMs explained 14-24% of the variance of the Aroclor 1242/LPCB and 22-39% for Aroclor 1254/HPCB serum concentrations. We regard the cumulative exposure estimated with the JEM as a better estimate of PCB body burdens than serum concentrations quantified as Aroclor 1242/LPCB and Aroclor 1254/HPCB.

The United Nations Educational, Scientific and Cultural Organisation: Pawn or Global Player?,

This contribution aims at exploring the significance of the new generation of UNESCO conventions for the recognition of higher education qualifications. It discusses three possible scenarios and links them to the empirical findings of a study that compares the enabling conditions of the first generation of recognition conventions established in the 1970s and 1980s with the ones establishing the second generation today. Taking an interdisciplinary approach, the paper argues that the changes illustrate a more general shift in the architecture of the global order and highlights a new role of UNESCO.

Conserved microRNA editing in mammalian evolution, development and disease.

BACKGROUND: Mammalian microRNAs (miRNAs) are sometimes subject to adenosine-to-inosine RNA editing, which can lead to dramatic changes in miRNA target specificity or expression levels. However, although a few miRNAs are known to be edited at identical positions in human and mouse, the evolution of miRNA editing has not been investigated in detail. In this study, we identify conserved miRNA editing events in a range of mammalian and non-mammalian species. RESULTS: We demonstrate deep conservation of several site-specific miRNA editing events, including two that date back to the common ancestor of mammals and bony fishes some 450 million years ago. We also find evidence of a recent expansion of an edited miRNA family in placental mammals and show that editing of these miRNAs is associated with changes in target mRNA expression during primate development and aging. While global patterns of miRNA editing tend to be conserved across species, we observe substantial variation in editing frequencies depending on tissue, age and disease state: editing is more frequent in neural tissues compared to heart, kidney and testis; in older compared to younger individuals; and in samples from healthy tissues compared to tumors, which together suggests that miRNA editing might be associated with a reduced rate of cell proliferation. CONCLUSIONS: Our results show that site-specific miRNA editing is an evolutionarily conserved mechanism, which increases the functional diversity of mammalian miRNA transcriptomes. Furthermore, we find that although miRNA editing is rare compared to editing of long RNAs, miRNAs are greatly overrepresented among conserved editing targets.