Pérégrinations entre sciences du langage et didactique des langues

Cet article livre le témoignage d’une jeune chercheure en didactique des langues dont le travail ressemble à celui de bien d’autres en linguistique appliquée. Pourtant, l’appartenance de ce travail à ce champ de recherche a été remise en question à plusieurs reprises. Ce témoignage est emblématique du parcours de chercheurs en didactique des langues, qui, sous le poids de l’histoire, ont oublié, caché, voire renié leurs liens avec la linguistique appliquée. Mais c’est aussi le témoignage d’une jeune chercheure, qui n’a pas vécu de l’intérieur les débats historiques et qui voit donc la situation avec un œil neuf. En quoi la recherche présentée appartient-elle à la didactique des langues ? à la linguistique appliquée ? Qu’est devenue cette dernière dans le paysage scientifique français ? Quelles questions peut-on se poser aujourd’hui pour l’aider à retrouver sa légitimité aux côtés de la didactique des langues ?This article delivers the testimony of a young researcher in language didactics whose work resembles many others in applied linguistics. However, in France, the belonging of this work to the latter research field has been denied several times. This testimony is emblematic of the path of some researchers in language didactics in France, who have had to forget, hide, or even deny their relations with applied linguistics, due to the historical positioning of language didactics. But it also is the testimony of a young researcher: she hasn’t lived the historical debates from the inside, so she sees the situation with a fresh eye. How is her work related to didactics? to applied linguistics? What became of the latter field in the French scientific landscape? What questions can we raise today to help it regain its legitimate place next to language didactics

Analyse des interactions et didactique des langues : tour d’horizon des relations

Cet article vise à poser le cadrage du numéro. Il expose la nature des apports de l’analyse des interactions à la didactique des langues-cultures en termes d’outils, de notions et de résultats. Il répertorie les relations que peuvent entretenir ces deux domaines, ainsi que les objets et champs investigués par les chercheurs. Ces derniers sont mis en rapport avec les contextes d’application : enseignement-apprentissage de langue étrangère, de langue seconde (en situation de migration), en milieu institutionnel ou naturel, pour des publics d’âges différents (enfants, adolescents ou adultes), ou en formation de formateurs. Nous reviendrons sur les échanges passés entre analyse des interactions et didactique des langues-cultures, mais nous explorerons surtout le tournant que prennent ces relations depuis les années 2010 : la didactique s’est d’abord approprié les outils et notions de l’analyse des interactions pour étudier la communication en contexte pédagogique, mais elle se tourne dorénavant vers l’étude d’interactions naturelles pour affiner la notion de compétence de communication, définir la compétence d’interaction (orale essentiellement) et préciser son processus de développement, compléter les contenus d’apprentissage, et former les nouvelles générations d’enseignants de langues.In this article, the authors set the context of the present issue. They consider the nature of the mutual contributions of two domains of research: Interaction Analysis and didactics of second/foreign languages and cultures. The authors look at the mutual contributions of these domains of research in terms of tools, notions and results. The article identifies the types of relations that bond them, as well as the objects and areas that researchers investigate. It explores the contexts in which the research takes place: teaching and learning a foreign or a second language (in a migration situation), be it in an institutional or natural situation, with learners of different ages (children, adolescents, adults), or in teacher training. The article evokes past exchanges between Interaction Analysis and didactics of second/foreign languages and cultures, but it lingers on the turn that their relations took in the years 2010. At first, didactics seized upon the tools and notions of Interaction Analysis in order to study pedagogical communication. Nowadays, natural conversations are also studied in order to sharpen the notion of communcation competence, define (essentially oral) interaction skills and precise the development processes of these skills. The aim is also to set learning goals, and train new generations of language teachers

Link between Intestinal CD36 Ligand Binding and Satiety Induced by a High Protein Diet in Mice

CD36 is a ubiquitous membrane glycoprotein that binds long-chain fatty acids. The presence of a functional CD36 is required for the induction of satiety by a lipid load and its role as a lipid receptor driving cellular signal has recently been demonstrated. Our project aimed to further explore the role of intestinal CD36 in the regulation of food intake. Duodenal infusions of vehicle or sulfo-N-succinimidyl-oleate (SSO) was performed prior to acute infusions of saline or Intralipid (IL) in mice. Infusion of minute quantities of IL induced a decrease in food intake (FI) compared to saline. Infusion of SSO had the same effect but no additive inhibitory effect was observed in presence of IL. No IL- or SSO-mediated satiety occurred in CD36-null mice. To determine whether the CD36-mediated hypophagic effect of lipids was maintained in animals fed a satietogen diet, mice were subjected to a High-Protein diet (HPD). Concomitantly with the satiety effect, a rise in intestinal CD36 gene expression was observed. No satiety effect occurred in CD36-null mice. HPD-fed WT mice showed a diminished FI compared to control mice, after saline duodenal infusion. But there was no further decrease after lipid infusion. The lipid-induced decrease in FI observed on control mice was accompanied by a rise in jejunal oleylethanolamide (OEA). Its level was higher in HPD-fed mice than in controls after saline infusion and was not changed by lipids. Overall, we demonstrate that lipid binding to intestinal CD36 is sufficient to produce a satiety effect. Moreover, it could participate in the satiety effect induced by HPD. Intestine can modulate FI by several mechanisms including an increase in OEA production and CD36 gene expression. Furthermore, intestine of mice adapted to HPD have a diminished capacity to modulate their food intake in response to dietary lipids

Extraction of pure components from overlapped signals in gas chromatography-mass spectrometry (GC-MS)

Gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique for the identification and quantification of trace chemicals in complex mixtures. When complex samples are analyzed by GC-MS it is common to observe co-elution of two or more components, resulting in an overlap of signal peaks observed in the total ion chromatogram. In such situations manual signal analysis is often the most reliable means for the extraction of pure component signals; however, a systematic manual analysis over a number of samples is both tedious and prone to error. In the past 30 years a number of computational approaches were proposed to assist in the process of the extraction of pure signals from co-eluting GC-MS components. This includes empirical methods, comparison with library spectra, eigenvalue analysis, regression and others. However, to date no approach has been recognized as best, nor accepted as standard. This situation hampers general GC-MS capabilities, and in particular has implications for the development of robust, high-throughput GC-MS analytical protocols required in metabolic profiling and biomarker discovery. Here we first discuss the nature of GC-MS data, and then review some of the approaches proposed for the extraction of pure signals from co-eluting components. We summarize and classify different approaches to this problem, and examine why so many approaches proposed in the past have failed to live up to their full promise. Finally, we give some thoughts on the future developments in this field, and suggest that the progress in general computing capabilities attained in the past two decades has opened new horizons for tackling this important problem

A new cloning system based on the OprI lipoprotein for the production of recombinant bacterial cell wall-derived immunogenic formulations

The conjugation of antigens with ligands of pattern recognition receptors (PRR) is emerging as a promising strategy for the modulation of specific immunity. Here, we describe a new Escherichia coli system for the cloning and expression of heterologous antigens in fusion with the OprI lipoprotein, a TLR ligand from the Pseudomonas aeruginosa outer membrane (OM). Analysis of the OprI expressed by this system reveals a triacylated lipid moiety mainly composed by palmitic acid residues. By offering a tight regulation of expression and allowing for antigen purification by metal affinity chromatography, the new system circumvents the major drawbacks of former versions. In addition, the anchoring of OprI to the OM of the host cell is further explored for the production of novel recombinant bacterial cell wall-derived formulations (OM fragments and OM vesicles) with distinct potential for PRR activation. As an example, the African swine fever virus ORF A104R was cloned and the recombinant antigen was obtained in the three formulations. Overall, our results validate a new system suitable for the production of immunogenic formulations that can be used for the development of experimental vaccines and for studies on the modulation of acquired immunity

Single-molecule kinetics of pore assembly by the membrane attack complex

The membrane attack complex (MAC) is a hetero-oligomeric protein assembly that kills pathogens by perforating their cell envelopes. The MAC is formed by sequential assembly of soluble complement proteins C5b, C6, C7, C8 and C9, but little is known about the rate-limiting steps in this process. Here, we use rapid atomic force microscopy (AFM) imaging to show that MAC proteins oligomerize within the membrane, unlike structurally homologous bacterial pore-forming toxins. C5b-7 interacts with the lipid bilayer prior to recruiting C8. We discover that incorporation of the first C9 is the kinetic bottleneck of MAC formation, after which rapid C9 oligomerization completes the pore. This defines the kinetic basis for MAC assembly and provides insight into how human cells are protected from bystander damage by the cell surface receptor CD59, which is offered a maximum temporal window to halt the assembly at the point of C9 insertion