Deciphering the molecular basis of mycobacteria and lipoglycan recognition by the C-type lectin Dectin-2

Dectin-2 is a C-type lectin involved in the recognition of several pathogens such as Aspergillus fumigatus, Candida albicans, Schistosoma mansonii, and Mycobacterium tuberculosis that triggers Th17 immune responses. Identifying pathogen ligands and understanding the molecular basis of their recognition is one of the current challenges. Purified M. tuberculosis mannose-capped lipoarabinomannan (ManLAM) was shown to induce signaling via Dectin-2, an activity that requires the (α1 → 2)-linked mannosides forming the caps. Here, using isogenic M. tuberculosis mutant strains, we demonstrate that ManLAM is a bona fide and actually the sole ligand mediating bacilli recognition by Dectin-2, although M. tuberculosis produces a variety of cell envelope mannoconjugates, such as phosphatidyl-myo-inositol hexamannosides, lipomannan or manno(lipo)proteins, that bear (α1 → 2)-linked mannosides. In addition, we found that Dectin-2 can recognize lipoglycans from other bacterial species, such as Saccharotrix aerocolonigenes or the human opportunistic pathogen Tsukamurella paurometabola, suggesting that lipoglycans are prototypical Dectin-2 ligands. Finally, from a structure/function relationship perspective, we show, using lipoglycan variants and synthetic mannodendrimers, that dimannoside caps and multivalent interaction are required for ligand binding to and signaling via Dectin-2. Better understanding of the molecular basis of ligand recognition by Dectin-2 will pave the way for the rational design of potent adjuvants targeting this receptor

RSF Governs Silent Chromatin Formation via Histone H2Av Replacement

Human remodeling and spacing factor (RSF) consists of a heterodimer of Rsf-1 and hSNF2H, a counterpart of Drosophila ISWI. RSF possesses not only chromatin remodeling activity but also chromatin assembly activity in vitro. While no other single factor can execute the same activities as RSF, the biological significance of RSF remained unknown. To investigate the in vivo function of RSF, we generated a mutant allele of Drosophila Rsf-1 (dRsf-1). The dRsf-1 mutant behaved as a dominant suppressor of position effect variegation. In dRsf-1 mutant, the levels of histone H3K9 dimethylation and histone H2A variant H2Av were significantly reduced in an euchromatic region juxtaposed with heterochromatin. Furthermore, using both genetic and biochemical approaches, we demonstrate that dRsf-1 interacts with H2Av and the H2Av-exchanging machinery Tip60 complex. These results suggest that RSF contributes to histone H2Av replacement in the pathway of silent chromatin formation

Traduction collaborative pour la scène

International audienc

The Gut Girls de Sarah Daniels, une expérience de traduction collaborative

International audienceBrief synopsis of The Gut Girls :The play tells the story of a small community, the “Gut Girls”, who work in a gutting shed at Deptford cattle market, in the South East of London in 1900. This work means they remain at the margins of society, but it also gives them some autonomy, gritty and distasteful as it is: the salary is higher than what women usually get, and they are, up to a point, considered equal to men. Because the work is hard, they use humour and irony to their heart’s content, and try to avoid Lady Helena’s club, which she has set up to teach them how to speak and behave properly. Unfortunately, the cattle market is soon to close, in the wake of progress in refrigerating meat. Each “Gut Girl” will have to find another way to survive: some will marry, most will become servants – and one of them may die as a consequence – and some will find jobs in a factory. Patriarchy, and capitalism, which had been questioned and jeopardised for a time by the small community of the “Gut Girls’, close down upon them, except perhaps one, who now works in a factory where they have a union.Our Project:We are a team of six researchers and translators from different universities, and we have set up to translate the play over the last year in a cooperative and collaborative way. We will present our work from different angles: its method (how is it possible for six translators to work together on the same text?), its translation (the play is riddled with puns linked to a particular sociolect, that of the working class in 1900 London) and its historical and literary context (But who are the “Gut Girls, and what does their work tell us?)Bref synopsis The Gut Girls :La pièce retrace le destin d’une petite communauté, celle des « Gut Girls », ouvrières travaillant dans les hangars d’éviscération du Marché aux Bestiaux de Deptford, à la périphérie de Londres, en 1900. Bien que leur activité les relègue en marge de la société, ce labeur peu ragoûtant leur permet de jouir d’une certaine autonomie, car leurs salaires sont supérieurs à ceux ordinairement octroyés aux femmes. Par ailleurs, la nature de leur travail les met sur un relatif pied d’égalité avec les hommes. Pour tenir dans des conditions aussi difficiles, elles manient sans modération l’humour et l’ironie et ne se rendent que sous la contrainte au club que Lady Helena a ouvert pour elles afin de leur inculquer les codes linguistiques et sociaux policés. Tout change avec la fermeture du Marché aux Bestiaux, lorsque la réfrigération naissante permet aux éleveurs de dépecer les bêtes sur place avant de les envoyer découpées alimenter les marchés de Londres. Chaque « Gut Girl » doit trouver un moyen pour survivre : certaines se marient, la plupart des autres entrent en domesticité – l’une d’entre elles le payera de sa vie -, d’autres vont travailler en usine. L’ordre patriarcal, ici mis en parallèle avec l’ordre capitaliste, un instant déstabilisé par la petite communauté des « Gut Girls » se referme sur elles toutes, à l’exception peut-être de l’une d’entre elles qui rejoint une usine où s’est monté un syndicat. Notre projet :Nous sommes une équipe de six enseignantes-chercheuses et traductrices d’universités différentes, qui traduisons la pièce depuis plus d’un an de manière coopérative et collaborative : nous présenterons notre travail sous les différents angles de sa méthode (comment peut-on traduire à six ?), du travail de traduction (en particulier la difficulté de rendre compte d’un sociolecte daté mais aussi des jeux de mots nombreux) et du travail d’analyse historique et littéraire (Qui sont les « Gut Girls » ? que nous raconte leur travail ?)

The Gut Girls de Sarah Daniels, une expérience de traduction collaborative

International audienceBrief synopsis of The Gut Girls :The play tells the story of a small community, the “Gut Girls”, who work in a gutting shed at Deptford cattle market, in the South East of London in 1900. This work means they remain at the margins of society, but it also gives them some autonomy, gritty and distasteful as it is: the salary is higher than what women usually get, and they are, up to a point, considered equal to men. Because the work is hard, they use humour and irony to their heart’s content, and try to avoid Lady Helena’s club, which she has set up to teach them how to speak and behave properly. Unfortunately, the cattle market is soon to close, in the wake of progress in refrigerating meat. Each “Gut Girl” will have to find another way to survive: some will marry, most will become servants – and one of them may die as a consequence – and some will find jobs in a factory. Patriarchy, and capitalism, which had been questioned and jeopardised for a time by the small community of the “Gut Girls’, close down upon them, except perhaps one, who now works in a factory where they have a union.Our Project:We are a team of six researchers and translators from different universities, and we have set up to translate the play over the last year in a cooperative and collaborative way. We will present our work from different angles: its method (how is it possible for six translators to work together on the same text?), its translation (the play is riddled with puns linked to a particular sociolect, that of the working class in 1900 London) and its historical and literary context (But who are the “Gut Girls, and what does their work tell us?)Bref synopsis The Gut Girls :La pièce retrace le destin d’une petite communauté, celle des « Gut Girls », ouvrières travaillant dans les hangars d’éviscération du Marché aux Bestiaux de Deptford, à la périphérie de Londres, en 1900. Bien que leur activité les relègue en marge de la société, ce labeur peu ragoûtant leur permet de jouir d’une certaine autonomie, car leurs salaires sont supérieurs à ceux ordinairement octroyés aux femmes. Par ailleurs, la nature de leur travail les met sur un relatif pied d’égalité avec les hommes. Pour tenir dans des conditions aussi difficiles, elles manient sans modération l’humour et l’ironie et ne se rendent que sous la contrainte au club que Lady Helena a ouvert pour elles afin de leur inculquer les codes linguistiques et sociaux policés. Tout change avec la fermeture du Marché aux Bestiaux, lorsque la réfrigération naissante permet aux éleveurs de dépecer les bêtes sur place avant de les envoyer découpées alimenter les marchés de Londres. Chaque « Gut Girl » doit trouver un moyen pour survivre : certaines se marient, la plupart des autres entrent en domesticité – l’une d’entre elles le payera de sa vie -, d’autres vont travailler en usine. L’ordre patriarcal, ici mis en parallèle avec l’ordre capitaliste, un instant déstabilisé par la petite communauté des « Gut Girls » se referme sur elles toutes, à l’exception peut-être de l’une d’entre elles qui rejoint une usine où s’est monté un syndicat. Notre projet :Nous sommes une équipe de six enseignantes-chercheuses et traductrices d’universités différentes, qui traduisons la pièce depuis plus d’un an de manière coopérative et collaborative : nous présenterons notre travail sous les différents angles de sa méthode (comment peut-on traduire à six ?), du travail de traduction (en particulier la difficulté de rendre compte d’un sociolecte daté mais aussi des jeux de mots nombreux) et du travail d’analyse historique et littéraire (Qui sont les « Gut Girls » ? que nous raconte leur travail ?)

Traduction collaborative pour la scène

International audienc

Specific Nutritional Requirements of Coconut Calli (Cocos nucifera L.) during Somatic Embryogenesis Induction

Summary Coconut calli were cultivated on two somatic embryogenesis induction media (SEIMs), differing in their 2,4-D content. Gain in dry matter weight, composition of soluble sugars within calli, but also pH and contents of glucose and macroelements in media were analysed at O, 15, 28, and 60 days of culture. Relationships between contents of endogenous sugars, on the one hand, and between contents of media macroelements, on the other hand, were analysed. Comparison was made with calli maintained on a control multiplication medium. Traits could be classified into 3 types of response with regard to condition of somatic embryogenesis induction (SEI condition). The first correspond to traits that were modified by the SEI condition and varying over time. Two phases were determined. During the first phase (TO-T15), soluble sugar contents within calli decreased over time. The higher the 2,4-D content in SEIMs, the higher the sugar contents. Consumption of glucose and macroelements in media was negligible. However, strong relationships in the contents of chloride, nitrate, phosphate, and sulfate were modified in the SEI condition. During the second phase (T15-T60, growth became lower in the SEI condition. Requirements for glucose, nitrate and phosphate and acidification .of media were higher. The relationship, determined by changes in nitrate and phosphate (R>0.98), was modified by the SEI conditions, showing a preferential consumption for nitrate in this case. Endogenous sucrose content decreased to become lower in the SEI condition. The higher the 2,4-D content in SEIMs, the higher the requirements for media compounds, the higher the contents of sugars within calli, but the lower the growth. The second type of response corresponded to traits modified by the SEI condition, but constant over time. It concerned relationships between contents of some cations in the media. The third type of response corresponded to traits unchanges by the SEI condition and over time. It concerned the high relationship contents of endogenous glucose and fructose (R = 0.88), and between contents of chloride, ammonium, calcium, magnesium, and potassium. Abbreviations: ANOVA = analysis of variance; ANCOVA = analysis of covariance; BAP = 6-benzylaminopurine; D M W = dry matter weight; FMW = fresh matter weight; % WC = percentage of water content; SEIM = somatic embryogenesis induction medium; TFMW = total fresh matter weight