Regulatory gateways for cell-specific gene expression in C4 leaves with Kranz anatomy.

C4 photosynthesis is a carbon-concentrating mechanism that increases delivery of carbon dioxide to RuBisCO and as a consequence reduces photorespiration. The C4 pathway is therefore beneficial in environments that promote high photorespiration. This pathway has evolved many times, and involves restricting gene expression to either mesophyll or bundle sheath cells. Here we review the regulatory mechanisms that control cell-preferential expression of genes in the C4 cycle. From this analysis, it is clear that the C4 pathway has a complex regulatory framework, with control operating at epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels. Some genes of the C4 pathway are regulated at multiple levels, and we propose that this ensures robust expression in each cell type. Accumulating evidence suggests that multiple genes of the C4 pathway may share the same regulatory mechanism. The control systems for C4 photosynthesis gene expression appear to operate in C3 plants, and so it appears that pre-existing mechanisms form the basis of C4 photosynthesis gene expression

Ancestral light and chloroplast regulation form the foundations for C4 gene expression.

C4 photosynthesis acts as a carbon concentrating mechanism that leads to large increases in photosynthetic efficiency. The C4 pathway is found in more than 60 plant lineages1 but the molecular enablers of this evolution are poorly understood. In particular, it is unclear how non-photosynthetic proteins in the ancestral C3 system have repeatedly become strongly expressed and integrated into photosynthesis gene regulatory networks in C4 leaves. Here, we provide clear evidence that in C3 leaves, genes encoding key enzymes of the C4 pathway are already co-regulated with photosynthesis genes and are controlled by both light and chloroplast-to-nucleus signalling. In C4 leaves this regulation becomes increasingly dependent on the chloroplast. We propose that regulation of C4 cycle genes by light and the chloroplast in the ancestral C3 state has facilitated the repeated evolution of the complex and convergent C4 trait.The work was funded by the European Union 3to4 project and Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/J011754/1. I.G.-M. was supported by the Amgen Foundation. Research on chloroplast signalling by M.J.T. was supported by BBSRC grant (BB/J018139/1).This is the author accepted manuscript. The final version is available from the Nature Publishing Group via http://dx.doi.org/10.1038/nplants.2016.16

CIGA: projecto de sistematização para a cerâmica islâmica do Gharb al-Ândalus

Nos últimos vinte anos, assistimos a um grande desenvolvimento da investigação acerca da cerâmica islâmica do Gharb al-Ândalus. Esta investigação foi desenvolvida a partir de iniciativas particulares. sem uma organização articulada de objectivos e estratégias de pesquisa. Actualmente, dispomos de uma informação desigual do ponto de vista geográfico, mas que já permite reunir dados de todas as áreas do território português em que o domínio islâmico perdurou até mais tarde. O grupo de trabalho CIGA está a desenvolver uma síntese dos conhecimentos disponíveis sobre a cerâmica islâmica do Gharb al-Ândalus, com o objectivo de verificar a existência de grupos cerâmicos coerentes no que respeita à distribuição geográfica, formas, técnicas de fabrica e ornamentação.Um factor especialmente interessante a equacionar é o contexto socio-económico dos sítios de proveniência dos materiais em estudo, verificando-se uma acentuada diferença entre contextos rurais e urbanos, mais intensa em períodos cronológicos mais recuados e mais ténue no final do domínio islâmico. Nesta comunicação apresenta-se um ponto de situação ao avanço dos trabalhos do projecto, numa fase ainda embrionária da investigação

Les activités sidérurgiques dans les campagnes du Gharb al-Andalus : l’exemple de la vallée du Mira (Bas Alentejo, sud du Portugal)

À l’aide de plusieurs exemples archéologiques récents, tous localisés dans la vallée du Mira, Bas Alentejo, les auteurs du présent article tentent de poser un certain nombre de questions relatives à l’exploitation des ressources ferrifères dans les campagnes du Gharb al-Andalus. Sont abordés différents thèmes, tels que l’origine et la nature des matières premières exploitées, les techniques sidérurgiques employées et les étapes de la chaîne opératoire présentes au sein des établissements ruraux, ainsi que les logiques de production et de distribution des produits sidérurgiques, probablement limités à des masses de fer brut destinées à la circulation (commerce ? paiement de l’impôt en nature ?). L’essentiel des données concerne le ixe siècle, mais la documentation disponible à l’heure actuelle ne va pas sans poser un certain nombre de problèmes méthodologiques, qui sont également abordés par les auteurs.In the present paper, based on recent archaeological work carried out in the River Mira valley, the authors intend to ask some questions related to the exploration of ferrous ressources in rural environment in the Gharb al-Andalus. Different themes are treated, as the origine and nature of raw materials, the siderurgical technics employed, the different stages of the ‘chaîne opératoire’ represented on the rural settlements, and the organization of production and distribution of the siderurgical products, probably limited to iron blooms destinated to circulation (trade? tax paying?). Most of the data concern the 9th century, but the documentation now available presents some methodological problems, which are also referred to by the authors

Les activités sidérurgiques dans les campagnes du Gharb al-Andalus : l’exemple de la vallée du Mira (Bas Alentejo, sud du Portugal)

In the present paper, based on recent archaeological work carried out in the River Mira valley, the authors intend to ask some questions related to the exploration of ferrous ressources in rural environment in the Gharb al-Andalus. Different themes are treated, as the origine and nature of raw materials, the siderurgical technics employed, the different stages of the ‘chaîne opératoire’ represented on the rural settlements, and the organization of production and distribution of the siderurgical products, probably limited to iron blooms destinated to circulation (trade? tax paying?). Most of the data concern the 9th century, but the documentation now available presents some methodological problems, which are also referred to by the authors

Next-generation ABACUS biosensors reveal cellular ABA dynamics driving root growth at low aerial humidity.

Funder: Gatsby Charitable Foundation; doi: https://doi.org/10.13039/501100000324The plant hormone abscisic acid (ABA) accumulates under abiotic stress to recast water relations and development. To overcome a lack of high-resolution sensitive reporters, we developed ABACUS2s-next-generation Förster resonance energy transfer (FRET) biosensors for ABA with high affinity, signal-to-noise ratio and orthogonality-that reveal endogenous ABA patterns in Arabidopsis thaliana. We mapped stress-induced ABA dynamics in high resolution to reveal the cellular basis for local and systemic ABA functions. At reduced foliar humidity, root cells accumulated ABA in the elongation zone, the site of phloem-transported ABA unloading. Phloem ABA and root ABA signalling were both essential to maintain root growth at low humidity. ABA coordinates a root response to foliar stresses, enabling plants to maintain foraging of deeper soil for water uptake

La céramique islamique du Garb Al-Ândalus: contextes socio-territoriaux et distribution

Apresentamos uma síntese da informação publicada sobre a cerâmica islâmica do Gharb Al-Ândalus (por enquanto apenas de Portugal) objectivando a existência de contextos sócio-territoriais, em conformidade com grupos cerâmicos coerentes no que respeita à forma, às técnicas de fabrico e à ornamentação.Um factor especialmente interessante é o do contexto socioeconómico dos sítios de proveniência dos materiais, verificando-se uma acentuada dissimilitude entre contextos rurais e urbanos, principalmente em períodos cronológicos mais recuados, que se atenua no final do domínio islâmico

Prevalence, characteristics and outcome of cardiac manifestations in critically-ill antiphospholipid syndrome patients

International audienc

Le monde rural dans l'Occident musulman médiéval

 L’Islam médiéval est un monde en grande partie rural qui n’a cependant été qu’assez peu étudié sous cet angle. La carence générale des études sur les campagnes est due à l’absence presque totale des documents d’archives. Les textes (chroniques, récits de voyage, ouvrages de géographes, bribes de traités fiscaux, etc.) dont disposent les historiens soulèvent des problèmes dans la mesure où ils émanent des milieux liés au pouvoir et présentent, lorsqu’ils l’évoquent, le monde rural dans une perspective avant tout urbaine.   Depuis une vingtaine d’années pourtant, des travaux fondés sur l’exploitation d’une documentation écrite et matérielle renouvelée, comme les écrits juridiques ou les fouilles de sites ruraux, abordent des voies inexplorées et offrent un nouveau visage de l’histoire rurale des pays d’Islam. De nombreuses disciplines sont mises à contribution - histoire, anthropologie, droit, géographie, archéologie - ce qui permet également un renouvellement méthodologique. Trois thèmes se dégagent des orientations récentes de recherches : les fondements de l’économie rurale, les structures de la société des campagnes et les rapports entre villes et espaces ruraux. Ce numéro, qui a choisi de privilégier l’Occident musulman, n’a pas l’ambition d’offrir un panorama complet de ces orientations mais il montre à quel point les possibilités de recherche ont progressé et permettent d’aboutir à une synthèse au moins partielle sur les structures de ce monde « hors les villes » et sur les nouveaux champs d’investigations qui s’offrent à l’historien comme à l’archéologue

A Bayesian reanalysis of the Standard versus Accelerated Initiation of Renal-Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial

Background Timing of initiation of kidney-replacement therapy (KRT) in critically ill patients remains controversial. The Standard versus Accelerated Initiation of Renal-Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial compared two strategies of KRT initiation (accelerated versus standard) in critically ill patients with acute kidney injury and found neutral results for 90-day all-cause mortality. Probabilistic exploration of the trial endpoints may enable greater understanding of the trial findings. We aimed to perform a reanalysis using a Bayesian framework. Methods We performed a secondary analysis of all 2927 patients randomized in multi-national STARRT-AKI trial, performed at 168 centers in 15 countries. The primary endpoint, 90-day all-cause mortality, was evaluated using hierarchical Bayesian logistic regression. A spectrum of priors includes optimistic, neutral, and pessimistic priors, along with priors informed from earlier clinical trials. Secondary endpoints (KRT-free days and hospital-free days) were assessed using zero–one inflated beta regression. Results The posterior probability of benefit comparing an accelerated versus a standard KRT initiation strategy for the primary endpoint suggested no important difference, regardless of the prior used (absolute difference of 0.13% [95% credible interval [CrI] − 3.30%; 3.40%], − 0.39% [95% CrI − 3.46%; 3.00%], and 0.64% [95% CrI − 2.53%; 3.88%] for neutral, optimistic, and pessimistic priors, respectively). There was a very low probability that the effect size was equal or larger than a consensus-defined minimal clinically important difference. Patients allocated to the accelerated strategy had a lower number of KRT-free days (median absolute difference of − 3.55 days [95% CrI − 6.38; − 0.48]), with a probability that the accelerated strategy was associated with more KRT-free days of 0.008. Hospital-free days were similar between strategies, with the accelerated strategy having a median absolute difference of 0.48 more hospital-free days (95% CrI − 1.87; 2.72) compared with the standard strategy and the probability that the accelerated strategy had more hospital-free days was 0.66. Conclusions In a Bayesian reanalysis of the STARRT-AKI trial, we found very low probability that an accelerated strategy has clinically important benefits compared with the standard strategy. Patients receiving the accelerated strategy probably have fewer days alive and KRT-free. These findings do not support the adoption of an accelerated strategy of KRT initiation