Friches et sectionaux

International audienceL'article analyse les rapports de micro collectivités de voisinage à une ancienne forme de propriété foncière collective du Massif central dans le but de comprendre les processus d'enfrichement. On montre que ceux-ci sont liés aux difficultés d'adaptation des anciens usages aux objectifs hétérogènes d'éleveurs considérés dans leurs relations avec les autres habitants

FORETS SECTIONALES ET SOCIETES LOCALES DANS LE MASSIF CENTRAL FRANCAIS

International audienceL'article examine les rapports des sociétés locales des montagnes du Massif central à une forme de propriété forestière collective. Il pose la question de la maîtrise par des microsociétés au terme d'un long déclin démographique, des enjeux liés à une colonisation forestière de leur territoire

: Peasantry heritage faces up to modernity : common lands and rural communities in Western European Highlands

Version modifiéeInternational audienceLes montagnes d’Europe occidentale apparaissent comme un conservatoire des diverses formes de propriété communautaire. Celle-ci a souvent été associée à une image archaïsante des sociétés rurales montagnardes. L'inertie des modes d'appropriation foncière témoignerait en quelque sorte des difficultés, voire d'une incapacité à intégrer un ordre néo-libéral marqué par les impératifs du productivisme au plan économique et par les manifestations de l'individualisme au plan social. Or le succès des conceptions localistes et endogènes du développement s'accompagne d'un intérêt nouveau porté au fait communautaire. Dès lors, la question d'une mobilisation de la terre commune dans une perspective de développement qui pouvait sembler incongrue il y a deux ou trois décennies, se pose désormais avec pertinence pour les acteurs des territoires ruraux montagnards. L'héritage paysan est toutefois porteur de significations ambivalentes tant au sein des sociétés locales qu’à un niveau politico-institutionnel supérieur

Substrate elucidation and mutasynthesis: Characterisation of the biosynthetic pathway of a tripyrrolic secondary metabolite, prodigiosin

A wide variety of biological activity can be found in the realm of secondary metabolites. The tripyrrole prodigiosin illustrates this perfectly with activities ranging from antimicrobial to immunosuppressive and anticancer. Microorganisms producing the red pigment prodigiosin were first isolated more than 150 years ago. Yet, its structure was only elucidated in the 1960s and the biosynthetic pathway remained mainly unknown until the 2000s. This secondary metabolite results from a bifurcated pathway where monopyrrole 2-methyl-3-pentyl-1H-pyrrole (MAP) and bipyrrole 4-methoxy-1H,1'H-2,2'-bipyrrole (MBC) are produced independently before condensation. As MBC is an intermediate in the synthesis of other natural products, the enzymes involved in its formation have been well characterised. In contrast, the three enzymes – PigD, PigE and PigB – involved in the formation of MAP are specific to the biosynthesis of prodigiosin and less is known about them. This thesis focuses on the latter two enzymes. PigE was first described as a transaminase catalysing the transformation of 3-acetyloctanal into 3-acetyloctylamine (which cyclises to form dihydroMAP) and this activity has been confirmed by feeding intermediates to various gene-knockout strains. However, in vitro studies have demonstrated that 3-acetyloctanal could not be the product of PigD. In addition, bioinformatics analysis of its amino acid sequence showed that PigE has two domains: a transaminase Cterminal moiety and an unspecified N-terminal one, which we propose is a thioester reductase that converts a 3-acetyloctanoyl thioester to 3-acetyloctanal. Attempted chemical complementation of a pigD-knockout strain of Serratia using synthetic thioester, carboxylic acid and aldehyde substrates showed that both the thioester and the aldehyde can be used for pigment production, indicating that a thioester reductase is involved in prodigiosin biosynthetic pathway. Furthermore, the PigE protein was expressed in a heterogeneous host, purified and submitted to a number of activity and kinetic assays, which demonstrated that it can reduce a 3-acetyloctanoyl thioester substrate. The oxidation of dihydroMAP to MAP had previously been shown to be catalysed by an FADdependent oxidase PigB. The kinetics of HapB, a homologue of PigB had been studied by a previous group member. To take this project further we studied the substrate flexibility of the enzyme and used it to form new analogues of prodigiosin by mutasynthesis. Ten analogues of dihydroMAP with modifications either in the C2 or C3 positions were synthesised. Both extensions and truncations in the length of the chain at the C3 position could be accepted, whereas alkyl chains longer than 3 carbons on the C2 position could not be accommodated. Similar results were found in vivo when the analogues were fed to a pigD-knockout strain of Serratia, showing that PigB and the condensing enzyme PigC shared similar flexibility. Eight analogues of prodigiosin were hence obtained and their antimicrobial activities against Gram-positive and Gram-negative bacteria were assessed.BBSRC Frances and Augustus Newman Fundatio

Espaces ruraux marginaux ou fragiles : les catégories analytiques à l’épreuve des pratiques socio-spatiales dans le Haut-Forez

Les termes « marginalité » et « fragilité » sont fréquemment associés à des espaces ruraux présentant diverses caractéristiques jugées défavorables tant dans les discours des observateurs que dans ceux d’une partie des acteurs. Dans un premier temps, une mise en perspective de l’usage des deux mots dans le cadre des sciences sociales permet de déterminer les apports possibles d’un point de vue géographique à une tentative de définition. Une fois le contenu des concepts précisés, leur caractère opératoire est testé dans une analyse des pratiques et stratégies d’acteurs à diverses échelles.Words like “marginality” or “fragility”, “sensitivity”, are often used to describe rural areas showing various features which are usually viewed with disfavour by academic observers and talked of negatively by (local) actors. To begin with, those words are put in perspective within the social sciences framework in order to establish the contribution of a geographical point of view to a definition. Once the concepts are clarified, they are used in a field research analysis so as to estimate their operational quality. actors, fragility, integration, marginalit

Cysteine–based redox regulation and signaling in plants

Living organisms are subjected to oxidative stress conditions which are characterized by the production of reactive oxygen, nitrogen, and sulfur species. In plants as in other organisms, many of these compounds have a dual function as they damage different types of macromolecules but they also likely fulfil an important role as secondary messengers. Owing to the reactivity of their thiol groups, some protein cysteine residues are particularly prone to oxidation by these molecules. In the past years, besides their recognized catalytic and regulatory functions, the modification of cysteine thiol group was increasingly viewed as either protective or redox signaling mechanisms. The most physiologically relevant reversible redox post-translational modifications (PTMs) are disulfide bonds, sulfenic acids, S-glutathione adducts, S-nitrosothiols and to a lesser extent S-sulfenyl-amides, thiosulfinates and S-persulfides. These redox PTMs are mostly controlled by two oxidoreductase families, thioredoxins and glutaredoxins. This review focuses on recent advances highlighting the variety and physiological roles of these PTMs and the proteomic strategies used for their detection

Stability of an oscillating tip in Non-Contact Atomic Force Microscopy: theoretical and numerical investigations.

This paper is a theoretical and a numerical investigation of the stability of a tip-cantilever system used in Non-Contact Atomic Force Microscopy (NC-AFM) when it oscillates close to a surface. No additional dissipative force is considered. The theoretical approach is based on a variationnal method exploiting a coarse grained operation that gives the temporal dependence of the nonlinear coupled equations of motion in amplitude and phase of the oscillator. Stability criterions for the resonance peak are deduced and predict a stable behavior of the oscillator in the vicinity of the resonance. The numerical approach is based on results obtained with a virtual NC-AFM developped in our group. The effect of the size of the stable domain in phase is investigated. These results are in particularly good agreement with the theoretical predictions. Also they show the influence of the phase shifter in the feedback loop and the way it can affect the damping signal

Tracking the consequences of design decisions in mechatronic systems engineering

19 pagesInternational audienceThe design of mechatronic systems involves several technical and scientific disciplines. It is often difficult to anticipate, at the outset, the consequences of design decisions on the ultimate effectiveness of such complex systems, in which case the evaluation process is required to support the designers each time engineering choices must be made or justified. Since designers may belong to different technical and scientific cultures however, their understanding of both the design stakes and the evaluation process is too often biased. Moreover, design choices take place in an uncertain context and according to multiple criteria, some of which may be contradictory. In order to track the consequences of design decisions, we are proposing a conceptual data model to perform evaluations within the MBSE framework of Systems Engineering. We then proceed by relying on the relationships demonstrated by such a model to identify the potential impacts of design choices on future product performance. Since data available during the conceptual phase of the design are typically uncertain or imprecise, an original research protocol is extended to a qualitative impact analysis for the purpose of highlighting the most promising alternative system design solutions (ASDS). An example in the mechatronics field serves to illustrate our proposals

Distinctive Mechanisms and Patterns of Exudative Versus Tractional Intraretinal Cystoid Spaces as Seen With Multimodal Imaging.

PurposeTo determine clear-cut distinctions between tractional and exudative intraretinal cystoid spaces subtypes.DesignRetrospective, multicenter, observational case series.MethodsA cohort of patients diagnosed with intraretinal cystoid spaces and imaged with optical coherence tomography (OCT), fluorescein angiography (FA), blue fundus autofluorescence (BFAF), en face OCT, and OCT angiography (OCT-A) was included in the study. All images were qualitatively and quantitatively evaluated.ResultsIn this study were included 72 eyes of 69 patients. Exudative intraretinal cystoid spaces (36/72 eyes, 50%) displayed a "petaloid" morphology as seen with en face OCT, FA, and BFAF. Tractional intraretinal cystoid spaces (24/72 eyes, 33.3%), displayed a radial "spoke-wheel" en face OCT pattern. There was no leakage with FA and BFAF did not reveal specific patterns. Eyes with full-thickness macular hole (FTMH, 12/72 eyes, 16.7%) displayed a "sunflower" en face OCT appearance. FTMH showed OCT, OCT-A, and BFAF features of both exudative and tractional cystoid spaces, but without any FA leakage. Inner nuclear layer (INL) thickness was significantly lower in tractional cystoid spaces (P < .001). There were a greater number of INL cystoid spaces in both the exudative and FTMH subgroups (P = .001). The surface area of INL cystoid spaces was significantly lower in the tractional subgroup (P < .001). There was a significant reduction of the microvascular density in eyes with exudative vs tractional (P = .002) and FTMH (P < .001) subgroups.ConclusionsExudative and tractional intraretinal cystoid spaces displayed characteristic multimodal imaging features and they may represent 2 different pathologic conditions with equally different clinical implications

Economie solidaire et espaces fragilisés auvergnats : une participation à la dynamique des territoires ? (Ambert, Saugues)

National audienceL'Auvergne rurale et l'Auvergne des petites villes apparaît comme un espace perdu, oublié, sans perspective de développement possible. Certes, la réalité tend parfois à confirmer une telle approche mais la nuance territoriale est fortement présente. De fait, l'économie sociale et solidaire est perçue fort différemment dans l'Ambertois et le Saugain. La première région, celle d'Ambert, présente une véritable dynamique liée à l'ESS ; celle-ci est un apport aux problématiques de développement local. L'ESS est considérée comme un outil généré par une citoyenneté active ou impulsé par les politiques locales. Cette citoyenneté s'inspire de l'attachement au local (histoire, enclavement, pérennité nécessaire...). Sur le second site, celui de la Margeride saugaine, l'ESS est davantage perçue comme un élément extérieur à la communauté locale ; élément qui risquerait de déstabiliser cette micro-société. Toutefois, une dynamique existe, bien qu'elle ait peine à s'exprimer, et l'avenir devrait se révéler porteur. En effet, cet espace connaît une mutation sociale où les pouvoirs vont être redistribués