Migrants expulsés au Mali : trouver un espace de représentation par le théâtre ?

Au Mali, l’utilisation du théâtre par les migrants expulsés organisés en associations ne se limite pas à un artifice formel. Elle est solidaire du fond des revendications sociales et politiques que ceux-ci souhaitent porter : apparaître et être reconnus comme des acteurs à part entière sur la scène publique, acquérir cette autonomie que leur dénient les instances politiques ou les formes traditionnelles de l’humanitaire, alerter l’opinion publique sur l’expulsion et sur les situations de précarité vécues après l’expulsion. Cette tentative des expulsés de produire une parole propre se heurte à d’autres usages du théâtre ; un théâtre promu par le gouvernement, qui stigmatise les dangers de l’émigration pour décourager les jeunes à partir, un théâtre sans les expulsés, qui offre d’eux une image compassionnelle, simples victimes d’un ordre politiquement injuste

Phages Preying on Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis: Past, Present and Future

Many bacteriophages (phages) have been widely studied due to their major role in virulence evolution of bacterial pathogens. However, less attention has been paid to phages preying on bacteria from the Bacillus cereus group and their contribution to the bacterial genetic pool has been disregarded. Therefore, this review brings together the main information for the B. cereus group phages, from their discovery to their modern biotechnological applications. A special focus is given to phages infecting Bacillus anthracis, B. cereus and Bacillus thuringiensis. These phages belong to the Myoviridae, Siphoviridae, Podoviridae and Tectiviridae families. For the sake of clarity, several phage categories have been made according to significant characteristics such as lifestyles and lysogenic states. The main categories comprise the transducing phages, phages with a chromosomal or plasmidial prophage state, γ-like phages and jumbo-phages. The current genomic characterization of some of these phages is also addressed throughout this work and some promising applications are discussed here

Prokaryotic microbiota outperform eukaryotic microbiota in differentiating between infection states of iconic diseases of two commercial oyster species

International audienceThe role of microbiota in health and disease is most often expressed by structural shifts of the taxonomic composition of prokaryote communities in infected and healthy individuals. In cultured aquatic animals with open circulatory systems, such as mollusks, microbiota also harbor a wide range of protists, which are unicellular eukaryotes that could also play an important role during infections. To evaluate the effectiveness of eukaryotic vs. prokaryotic microbiota in characterizing infection states, we examined both microbial compartments under natural conditions in two commercially important oyster species, the flat oyster Ostrea edulis and the Pacific oyster Magallana (Crassostrea) gigas. With O. edulis being infected by two protist parasites, Marteilia refringens and Bonamia ostreae, and M. gigas being infected by the ostreid herpes virus OsHV-1, we chose iconic diseases responsible for substantial mortalities and economic damage within the two species. We analyzed and compared the structural and compositional differences between healthy and infected oysters and used random forest machine learning to classify infection states and identify indicator taxa that distinguish healthy from infected individuals. Both at the structural and compositional levels, bacterial microbiota proved to be better predictors of infection states. By eliminating noisy taxa through variable selection in the random forest models, we enhanced the compositional differences between infection states. In all host-pathogen combinations, only a few taxa (<31) were required to achieve optimal separation. While the identity of indicator taxa will partly reflect the specific environmental conditions at the time of sampling, we recovered several previously described indicator taxa, such as Mycoplasma, Vibrio, Photobacterium, and Arcobacter. Next to these we also discovered new taxa like Motiliproteus that exhibited the potential to differentiate between infection states of the investigated O. edulis specimen. The simultaneous characterization of prokaryotic and eukaryotic microbiota suggests that only few prokaryotic indicator species might be needed to reliably differentiate between infected from healthy individuals and monitor infection risks

Environmental distribution and seasonal dynamics of Marteilia refringens and Bonamia ostreae, two protozoan parasites of the European flat oyster, Ostrea edulis

IntroductionMarteilia refringens and Bonamia ostreae are protozoan parasites responsible for mortalities of farmed and wild flat oysters Ostrea edulis in Europe since 1968 and 1979, respectively. Despite almost 40 years of research, the life-cycle of these parasites is still poorly known, especially regarding their environmental distribution.MethodsWe carried out an integrated field study to investigate the dynamics of M. refringens and B. ostreae in Rade of Brest, where both parasites are known to be present. We used real-time PCR to monitor seasonally over four years the presence of both parasites in flat oysters. In addition, we used previously developed eDNA based-approaches to detect parasites in planktonic and benthic compartments for the last two years of the survey.ResultsM. refringens was detected in flat oysters over the whole sampling period, sometimes with a prevalence exceeding 90%. It was also detected in all the sampled environmental compartments, suggesting their involvement in parasite transmission and overwintering. In contrast, B. ostreae prevalence in flat oysters was low and the parasite was almost never detected in planktonic and benthic compartments. Finally, the analysis of environmental data allowed describing the seasonal dynamics of both parasites in Rade of Brest: M. refringens was more detected in summer and fall than in winter and spring, contrary to B. ostreae which showed higher prevalence in winter and spring.DiscussionThe present study emphasizes the difference between M. refringens and B. ostreae ecology, the former presenting a wider environmental distribution than the latter, which seems closely associated to flat oysters. Our findings highlight the key role of planktonic and benthic compartments in M. refringens transmission and storage or potential overwintering, respectively. More generally, we provide here a method that could be useful not only to further investigate non cultivable pathogens life-cycle, but also to support the design of more integrated surveillance programs

Émergence d’un nouveau péronisme ? Analyse des discours à la Nation de Néstor Kirchner (2003-2007)

L’étude des discours de Néstor Kirchner permet d’identifier les représentations sociales qu’il a mobilisées, et de montrer comment il s’inscrit dans le contexte du « virage à gauche » qui singularise aujourd’hui l’Amérique latine. Ses allocutions devant l’Assemblée nationale peuvent s’analyser sous l’angle de l’héritage péroniste, et particulièrement de l’imaginaire de la génération des années soixante-dix, et lui ont permis de transformer son image d’homme politique non charismatique en celle d’un leader providentiel.The analysis of Néstor Kirchner’s speeches enables us to account for the social representations he has deployed and show to what extent he lies within the scope of the currently prevailing « shift to the left » context in Latin America. His speeches before the members of Parliament can be analysed within the framework of the Peronist legacy and more particularly the 1970’s generation’s worldview. Thanks to those speeches, his public image has undergone a real transformation from one of a politician with little charisma to that of a providential leader.El estudio de los discursos de Néstor Kirchner permite identificar las representaciones sociales por él movilizadas y mostrar de qué modo el mismo se inscribe en el proceso de « viraje a la izquierda » que hoy define al contexto político latinoamericano. Sus discursos ante el Parlamento pueden ser analizados bajo la vigencia de la tradición peronista, sobre todo del imaginario de la generación del setenta, transformando su imagen de líder político no carismático en la figura de líder providencial

Minor Keywords of Political Theory: Migration as a Critical Standpoint. A collaborative project of collective writing

Coordinated and Edited by: N De Genova, M Tazzioli Co-Authored by: Claudia Aradau, Brenna Bhandar, Manuela Bojadzijev, Josue David Cisneros, N De Genova, Julia Eckert, Elena Fontanari, Tanya Golash-Boza, Jef Huysmans, Shahram Khosravi, Clara Lecadet, Patrisia Macías-Rojas, Federica Mazzara, Anne McNevin, Peter Nyers, Stephan Scheel, Nandita Sharma, Maurice Stierl, Vicki Squire, M Tazzioli, Huub van Baar and William Walter

Molecular basis for group-specific activation of the virulence regulator PlcR by PapR heptapeptides

The transcriptional regulator PlcR and its cognate cell–cell signalling peptide PapR form a quorum-sensing system that controls the expression of extra-cellular virulence factors in various species of the Bacillus cereus group. PlcR and PapR alleles are clustered into four groups defining four pherotypes. However, the molecular basis for group specificity remains elusive, largely because the biologically relevant PapR form is not known. Here, we show that the in vivo active form of PapR is the C-terminal heptapeptide of the precursor, and not the pentapeptide, as previously suggested. Combining genetic complementation, anisotropy assays and structural analysis we provide a detailed functional and structural explanation for the group specificity of the PlcR–PapR quorum-sensing system. We further show that the C-terminal helix of the PlcR regulatory domain, specifically the 278 residue, in conjunction with the N-terminal residues of the PapR heptapeptide determines this system specificity. Variability in the specificity-encoding regions of plcR and papR genes suggests that selection and evolution of quorum-sensing systems play a major role in adaptation and ecology of Bacilli

A Naturally Occurring Plant Cysteine Protease Possesses Remarkable Toxicity against Insect Pests and Synergizes Bacillus thuringiensis Toxin

When caterpillars feed on maize (Zea maize L.) lines with native resistance to several Lepidopteran pests, a defensive cysteine protease, Mir1-CP, rapidly accumulates at the wound site. Mir1-CP has been shown to inhibit caterpillar growth in vivo by attacking and permeabilizing the insect's peritrophic matrix (PM), a structure that surrounds the food bolus, assists in digestion and protects the midgut from microbes and toxins. PM permeabilization weakens the caterpillar defenses by facilitating the movement of other insecticidal proteins in the diet to the midgut microvilli and thereby enhancing their toxicity. To directly determine the toxicity of Mir1-CP, the purified recombinant enzyme was directly tested against four economically significant Lepidopteran pests in bioassays. Mir1-CP LC50 values were 1.8, 3.6, 0.6, and 8.0 ppm for corn earworm, tobacco budworm, fall armyworm and southwestern corn borer, respectively. These values were the same order of magnitude as those determined for the Bacillus thuringiensis toxin Bt-CryIIA. In addition to being directly toxic to the larvae, 60 ppb Mir1-CP synergized sublethal concentrations of Bt-CryIIA in all four species. Permeabilization of the PM by Mir1-CP probably provides ready access to Bt-binding sites on the midgut microvilli and increases its activity. Consequently, Mir1-CP could be used for controlling caterpillar pests in maize using non-transgenic approaches and potentially could be used in other crops either singly or in combination with Bt-toxins

Immunological and Metabolomic Impacts of Administration of Cry1Ab Protein and MON 810 Maize in Mouse

We have investigated the immunological and metabolomic impacts of Cry1Ab administration to mice, either as a purified protein or as the Cry1Ab-expressing genetically modified (GM) MON810 maize. Humoral and cellular specific immune responses induced in BALB/cJ mice after intra-gastric (i.g.) or intra-peritoneal (i.p.) administration of purified Cry1Ab were analyzed and compared with those induced by proteins of various immunogenic and allergic potencies. Possible unintended effects of the genetic modification on the pattern of expression of maize natural allergens were studied using IgE-immunoblot and sera from maize-allergic patients. Mice were experimentally sensitized (i.g. or i.p. route) with protein extracts from GM or non-GM maize, and then anti-maize proteins and anti-Cry1Ab–induced immune responses were analyzed. In parallel, longitudinal metabolomic studies were performed on the urine of mice treated via the i.g. route. Weak immune responses were observed after i.g. administration of the different proteins. Using the i.p. route, a clear Th2 response was observed with the known allergenic proteins, whereas a mixed Th1/Th2 immune response was observed with immunogenic protein not known to be allergenic and with Cry1Ab. This then reflects protein immunogenicity in the BALB/c Th2-biased mouse strain rather than allergenicity. No difference in natural maize allergen profiles was evidenced between MON810 and its non-GM comparator. Immune responses against maize proteins were quantitatively equivalent in mice treated with MON810 vs the non-GM counterpart and no anti-Cry1Ab–specific immune response was detected in mice that received MON810. Metabolomic studies showed a slight “cultivar” effect, which represented less than 1% of the initial metabolic information. Our results confirm the immunogenicity of purified Cry1Ab without evidence of allergenic potential. Immunological and metabolomic studies revealed slight differences in mouse metabolic profiles after i.g. administration of MON810 vs its non-GM counterpart, but no significant unintended effect of the genetic modification on immune responses was seen

Necrotrophism Is a Quorum-Sensing-Regulated Lifestyle in Bacillus thuringiensis

How pathogenic bacteria infect and kill their host is currently widely investigated. In comparison, the fate of pathogens after the death of their host receives less attention. We studied Bacillus thuringiensis (Bt) infection of an insect host, and show that NprR, a quorum sensor, is active after death of the insect and allows Bt to survive in the cadavers as vegetative cells. Transcriptomic analysis revealed that NprR regulates at least 41 genes, including many encoding degradative enzymes or proteins involved in the synthesis of a nonribosomal peptide named kurstakin. These degradative enzymes are essential in vitro to degrade several substrates and are specifically expressed after host death suggesting that Bt has an active necrotrophic lifestyle in the cadaver. We show that kurstakin is essential for Bt survival during necrotrophic development. It is required for swarming mobility and biofilm formation, presumably through a pore forming activity. A nprR deficient mutant does not develop necrotrophically and does not sporulate efficiently in the cadaver. We report that necrotrophism is a highly regulated mechanism essential for the Bt infectious cycle, contributing to spore spreading