La perception des enjeux économiques et sociaux, et leur influence sur le vote du 22 avril 2007

Tous les sondages précédant le scrutin, à commencer par les 4 vagues du Baromètre politique français ont montré la centralité des enjeux socio économiques dans la campagne présidentielle de 2007. C’est ce que confirme la première vague du Panel électoral français (PEF), terminée à la veille du scrutin du 22 avril : le chômage arrive largement en tête des problèmes cités comme les plus importants au moment de voter, suivi par les inégalités sociales et le pouvoir d’achat (classés en premier par respectivement 25, 12 et 10% de l’échantillon, et en premier ou en second par 39, 22 et 25%) (...)

Exploring the potential of cell-based models in simulating tissue biophysics in plant morphogenesis: the case of woody tissues.

This thesis considers the status of computational modelling in plant biology. After a brief introduction to modelling in biology, the reader is introduced to different approaches and tool. Among them, cell-based modelling is chosen to first model the effect of cell wall mechanics over tissue growth, and then xylogenesis of a generic conifer is simulated. In order to do so, the VirtualLeaf modelling framework has been used and extended with a description of the mechanical effects of thickness over cell dynamics. The frameworks proved itself a good tool for modeling such dynamics, and the output of the simulations suggest that tissue properties like growth anisotropy and proliferation rate (in the first case) and early- to latewood transition (in the second case) could be strongly linked to mechanical cell-autonomous properties and cell-cell interaction

Impact of invasion and management of molasses grass (Melinis minutiflora) on the native vegetation of the Brazilian Savanna

No Brasil, várias espécies de gramíneas são citadas como invasoras em Unidades de Conservação. Contudo, ainda se conhece muito pouco sobre o impacto do estabelecimento e da colonização dessas espécies nas áreas protegidas. Entre as gramíneas exóticas introduzidas no bioma Cerrado merece destaque a espécie africana Melinis minutiflora P. Beauv., o capim-gordura. O presente estudo objetivou avaliar o impacto desta invasora na biomassa e na riqueza da comunidade nativa em uma área de Cerrado Ralo invadido, como também estudar a dinâmica da vegetação do estrato rasteiro submetida à aplicação de diferentes técnicas de manejo para o controle do capim-gordura. Os resultados mostraram que, na área experimental, onde o capimgordura representa cerca 62% da biomassa total do estrato rasteiro, o número de espécies nativas encontradas foi alto. Nas áreas onde o capim-gordura apresentou alto índice de colonização (> 98%), sua biomassa alcançou cerca de duas vezes a biomassa do estrato rasteiro registrada para o Cerrado. A realização de uma queimada não foi suficiente para controlar o capim-gordura, porque após três anos a sua biomassa se aproximou aos valores encontrados inicialmente. Por outro lado, no tratamento manejo integrado (maio ou setembro) a redução de mais de 99,9% na sua presença favoreceu a expansão da vegetação nativa, configurando-se, assim, uma estratégia promissora para a recuperação ambiental das áreas invadidas pelo capim-gordura no Cerrado.In Brazil, several grass species are cited as invaders of protected areas. However, little is known about the impacts due to establishment and colonization of these species in protected areas in Brazil. Among the exotic grasses introduced into the Cerrado the African species Melinis minutiflora P. Beauv., molasses grass, deserves special mention. The objective of this study was to evaluate the impact of this grass on the biomass and species richness of the native community in an area of invaded Cerrado as well as to study the dynamics of the vegetation of the ground layer after different management treatments for control of molasses grass. The results showed that in the experimental area, where molasses grass composed 62% of the total biomass of the ground layer, the number of native species was high. In the areas where molasses grass had a high degree of coverage (> 98%) its biomass was approximately two times higher than values cited in other studies in the Cerrado. Between three and four years after using fire as a management tool for control of molasses grass its biomass returned to values similar to those observed prior to this treatment. Contrarily, with an integrated management treatment (May or September) a reduction of 99.9% in the presence of molasses grass was observed along with a recovery of native vegetation, making this a promising strategy for recuperation of areas in the Cerrado that were invaded by molasses grass

Enzyme Replacement Therapy for FABRY Disease: Possible Strategies to Improve Its Efficacy

Enzyme replacement therapy is the only therapeutic option for Fabry patients with completely absent AGAL activity. However, the treatment has side effects, is costly, and requires conspicuous amounts of recombinant human protein (rh-AGAL). Thus, its optimization would benefit patients and welfare/health services (i.e., society at large). In this brief report, we describe preliminary results paving the way for two possible approaches: i. the combination of enzyme replacement therapy with pharmacological chaperones; and ii. the identification of AGAL interactors as possible therapeutic targets on which to act. We first showed that galactose, a low-affinity pharmacological chaperone, can prolong AGAL half-life in patient-derived cells treated with rh-AGAL. Then, we analyzed the interactomes of intracellular AGAL on patient-derived AGAL-defective fibroblasts treated with the two rh-AGALs approved for therapeutic purposes and compared the obtained interactomes to the one associated with endogenously produced AGAL (data available as PXD039168 on ProteomeXchange). Common interactors were aggregated and screened for sensitivity to known drugs. Such an interactor-drug list represents a starting point to deeply screen approved drugs and identify those that can affect (positively or negatively) enzyme replacement therapy

Interplay between chromophore binding and domain assembly by the B₁₂-dependent photoreceptor protein, CarH.

From Europe PMC via Jisc Publications RouterHistory: ppub 2021-05-01, epub 2021-05-05Publication status: PublishedFunder: Biotechnology and Biological Sciences Research Council; Grant(s): BB/L002655/1, BB/L016486/1, BB/M011208/1Organisms across the natural world respond to their environment through the action of photoreceptor proteins. The vitamin B12-dependent photoreceptor, CarH, is a bacterial transcriptional regulator that controls the biosynthesis of carotenoids to protect against photo-oxidative stress. The binding of B12 to CarH monomers in the dark results in the formation of a homo-tetramer that complexes with DNA; B12 photochemistry results in tetramer dissociation, releasing DNA for transcription. Although the details of the response of CarH to light are beginning to emerge, the biophysical mechanism of B12-binding in the dark and how this drives domain assembly is poorly understood. Here - using a combination of molecular dynamics simulations, native ion mobility mass spectrometry and time-resolved spectroscopy - we reveal a complex picture that varies depending on the availability of B12. When B12 is in excess, its binding drives structural changes in CarH monomers that result in the formation of head-to-tail dimers. The structural changes that accompany these steps mean that they are rate-limiting. The dimers then rapidly combine to form tetramers. Strikingly, when B12 is scarcer, as is likely in nature, tetramers with native-like structures can form without a B12 complement to each monomer, with only one apparently required per head-to-tail dimer. We thus show how a bulky chromophore such as B12 shapes protein/protein interactions and in turn function, and how a protein can adapt to a sub-optimal availability of resources. This nuanced picture should help guide the engineering of B12-dependent photoreceptors as light-activated tools for biomedical applications

Oxidoreductases and metal cofactors in the functioning of the earth

: Life sustains itself using energy generated by thermodynamic disequilibria, commonly existing as redox disequilibria. Metals are significant players in controlling redox reactions, as they are essential components of the engine that life uses to tap into the thermodynamic disequilibria necessary for metabolism. The number of proteins that evolved to catalyze redox reactions is extraordinary, as is the diversification level of metal cofactors and catalytic domain structures involved. Notwithstanding the importance of the topic, the relationship between metals and the redox reactions they are involved in has been poorly explored. This work reviews the structure and function of different prokaryotic organometallic-protein complexes, highlighting their pivotal role in controlling biogeochemistry. We focus on a specific subset of metal-containing oxidoreductases (EC1 or EC7.1), which are directly involved in biogeochemical cycles, i.e., at least one substrate or product is a small inorganic molecule that is or can be exchanged with the environment. Based on these inclusion criteria, we select and report 59 metalloenzymes, describing the organometallic structure of their active sites, the redox reactions in which they are involved, and their biogeochemical roles

An Individual Based Model of Wound Closure in Plant Stems

Wound closure in plant stems (after either fire or mechanical damage) is a complex, multi-scale process that involves the formation of a callous tissue (callus lips) responsible for cell proliferation and overgrowth at the injury edges, resulting in coverage of the scarred tissue. Investigating such phenomena, it is difficult to discriminate between cell-specific growth responses, associated with physiological adaptations, and cell proliferation reactions emerging from specific cambium dynamics due to changes in mechanical constrains. In particular, the effects of cell–cell mechanical interactions on the wound closure process have never been investigated. To understand to what extent callus lip formation depends on the intra-tissue mechanical balance of forces, we built a simplified individual-based model (IBM) of cell division and differentiation in a generic woody tissue. Despite its simplified physiological assumptions, the model was capable to simulate callus hyperproliferation and wound healing as an emergent property of the mechanical interactions between individual cells. The model output suggests that the existence of a scar alone does constrain the growth trajectories of the remaining proliferating cells around the injury, thus resulting in the wound closure, ultimately engulfing the damaged tissue in the growing stem

Identification of Genes Critical for Resistance to Infection by West Nile Virus Using RNA-Seq Analysis

The West Nile virus (WNV) is an emerging infection of biodefense concern and there are no available treatments or vaccines. Here we used a high-throughput method based on a novel gene expression analysis, RNA-Seq, to give a global picture of differential gene expression by primary human macrophages of 10 healthy donors infected in vitro with WNV. From a total of 28 million reads per sample, we identified 1,514 transcripts that were differentially expressed after infection. Both predicted and novel gene changes were detected, as were gene isoforms, and while many of the genes were expressed by all donors, some were unique. Knock-down of genes not previously known to be associated with WNV resistance identified their critical role in control of viral infection. Our study distinguishes both common gene pathways as well as novel cellular responses. Such analyses will be valuable for translational studies of susceptible and resistant individuals—and for targeting therapeutics—in multiple biological settings