INCLUSION SOCIALE, ENTRE COURANTS D’AIR ET ENFERMEMENTS ?

L’expression « société inclusive », inscrite aujourd’hui dans de nombreux discours relevant de la sociologie urbaine, arrive toutdroit des programmes onusiens des années 1990. Elle fait suite, en Europe tout du moins, à une autre appellation, coutumièredes contextes de migrations de populations, « la société d’accueil ». On passe ainsi de l’accompagnement des arrivées et del’intégration des minorités sujets/objets de l’immigration à un projet de société qui relève de la défenses des intérêts de lamajorité, même s’il s’annonce comme opposé à toutes les formes de refus et d’exclusion que 3 générations de « migrants » n’ontpas réussi à éradiquer. Il semblerait bien que l’inclusion renvoie ainsi aujourd’hui à un double enjeu, difficilement maîtrisable : lamise en place polymorphe de dispositifs permettant au groupe social de se défendre contre les intrusions et autres marginalités,et tout à la fois la possibilité donnée à chaque citoyen de se retrouver partie prenante et agissante de ce corps social qui lui donnerepères et moyens d’une construction de son identité

INCLUSION SOCIALE, ENTRE COURANTS D’AIR ET ENFERMEMENTS ?

L’expression « société inclusive », inscrite aujourd’hui dans de nombreux discours relevant de la sociologie urbaine, arrive toutdroit des programmes onusiens des années 1990. Elle fait suite, en Europe tout du moins, à une autre appellation, coutumièredes contextes de migrations de populations, « la société d’accueil ». On passe ainsi de l’accompagnement des arrivées et del’intégration des minorités sujets/objets de l’immigration à un projet de société qui relève de la défenses des intérêts de lamajorité, même s’il s’annonce comme opposé à toutes les formes de refus et d’exclusion que 3 générations de « migrants » n’ontpas réussi à éradiquer. Il semblerait bien que l’inclusion renvoie ainsi aujourd’hui à un double enjeu, difficilement maîtrisable : lamise en place polymorphe de dispositifs permettant au groupe social de se défendre contre les intrusions et autres marginalités,et tout à la fois la possibilité donnée à chaque citoyen de se retrouver partie prenante et agissante de ce corps social qui lui donnerepères et moyens d’une construction de son identité

Identification of a novel gene encoding a flavin-dependent tRNA:m(5)U methyltransferase in bacteria—evolutionary implications

Formation of 5-methyluridine (ribothymidine) at position 54 of the T-psi loop of tRNA is catalyzed by site-specific tRNA methyltransferases (tRNA:m(5)U-54 MTase). In all Eukarya and many Gram-negative Bacteria, the methyl donor for this reaction is S-adenosyl-l-methionine (S-AdoMet), while in several Gram-positive Bacteria, the source of carbon is N(5), N(10)-methylenetetrahydrofolate (CH(2)H(4)folate). We have identified the gene for Bacillus subtilis tRNA:m(5)U-54 MTase. The encoded recombinant protein contains tightly bound flavin and is active in Escherichia coli mutant lacking m(5)U-54 in tRNAs and in vitro using T7 tRNA transcript as substrate. This gene is currently annotated gid in Genome Data Banks and it is here renamed trmFO. TrmFO (Gid) orthologs have also been identified in many other bacterial genomes and comparison of their amino acid sequences reveals that they are phylogenetically distinct from either ThyA or ThyX class of thymidylate synthases, which catalyze folate-dependent formation of deoxyribothymine monophosphate, the universal DNA precursor

Éduquer aujourd’hui en Afrique ?

L’Éducation nationale cherche à réaliser, avec difficultés, instruction et insertion socio-professionnelle. Ce modèle est transféré sur les pays colonisés ou aidés (colloquisés), sans adaptation. Les élites formées de ces pays perpétuent ce mouvement. Il convient de rajouter les difficultés matérielles ou géographiques qui rendent difficile la scolarité des jeunes. Cette situation conduit néanmoins à des formes originales d’éducation qui sont le fruit d’initiatives populaires fondées sur des notions d’utilité collective, de solidarité, de survie... Il y a là réellement une démarche innovante, pragmatique, qui a l’avantage d’entraîner tous les enfants et de les motiver

Colonialité et occidentalocentrisme : quels enjeux pour la production des savoirs ?

Cet article porte sur les rapports de pouvoir dans la production des savoirs scientifiques, qui peuvent rendre compte de l’imbrication de la science et du politique. Il interroge plus particulièrement l’existence et l’influence d’un phénomène ostracisant et questionne la prétention à l’universalité des paradigmes et des modèles utilisés par les institutions savantes occidentales et leurs représentants. À travers une posture réflexive et critique, une démarche méthodologique inductive et des éléments issus d’une revue de littérature, les auteurs concentrent leur attention sur les nouvelles formes de pertinence attribuées à la notion de colonialité. Celle-ci constitue un concept opératoire dans l’analyse des conflits de normes et des écarts sociaux et culturels, et une grille de lecture expliquant les hiérarchies installées dans la diffusion des savoirs et la perdurance de collectifs subalternisés.This article deals with the power relations in the production of scientific knowledge, which highlights the imbrication of science and politics. It focuses on the existence and the influence of an ostracizing phenomenon that questions the universality claim in the science framework and scientific paradigms theorized in the (mainly Western) learned bodies. Adopting a reflexive and critique posture and using an inductive methodological approach and some elements from a literature review, the authors aim to shed light on the new forms of relevance attributed to the notion of coloniality. It provides a concept that may be enforced in the analysis of norms conflicts and social and cultural gaps. Il also constitutes an analytical grid of the hierarchy in the spread of knowledge and the subsistence of subaltern groups

The RNA polymerase III-dependent family of genes in hemiascomycetes: comparative RNomics, decoding strategies, transcription and evolutionary implications

We present the first comprehensive analysis of RNA polymerase III (Pol III) transcribed genes in ten yeast genomes. This set includes all tRNA genes (tDNA) and genes coding for SNR6 (U6), SNR52, SCR1 and RPR1 RNA in the nine hemiascomycetes Saccharomyces cerevisiae, Saccharomyces castellii, Candida glabrata, Kluyveromyces waltii, Kluyveromyces lactis, Eremothecium gossypii, Debaryomyces hansenii, Candida albicans, Yarrowia lipolytica and the archiascomycete Schizosaccharomyces pombe. We systematically analysed sequence specificities of tRNA genes, polymorphism, variability of introns, gene redundancy and gene clustering. Analysis of decoding strategies showed that yeasts close to S.cerevisiae use bacterial decoding rules to read the Leu CUN and Arg CGN codons, in contrast to all other known Eukaryotes. In D.hansenii and C.albicans, we identified a novel tDNA-Leu (AAG), reading the Leu CUU/CUC/CUA codons with an unusual G at position 32. A systematic ‘p-distance tree’ using the 60 variable positions of the tRNA molecule revealed that most tDNAs cluster into amino acid-specific sub-trees, suggesting that, within hemiascomycetes, orthologous tDNAs are more closely related than paralogs. We finally determined the bipartite A- and B-box sequences recognized by TFIIIC. These minimal sequences are nearly conserved throughout hemiascomycetes and were satisfactorily retrieved at appropriate locations in other Pol III genes

RNomics and Modomics in the halophilic archaea Haloferax volcanii: identification of RNA modification genes

<p>Abstract</p> <p>Background</p> <p>Naturally occurring RNAs contain numerous enzymatically altered nucleosides. Differences in RNA populations (RNomics) and pattern of RNA modifications (Modomics) depends on the organism analyzed and are two of the criteria that distinguish the three kingdoms of life. If the genomic sequences of the RNA molecules can be derived from whole genome sequence information, the modification profile cannot and requires or direct sequencing of the RNAs or predictive methods base on the presence or absence of the modifications genes.</p> <p>Results</p> <p>By employing a comparative genomics approach, we predicted almost all of the genes coding for the t+rRNA modification enzymes in the mesophilic moderate halophile <it>Haloferax volcanii</it>. These encode both guide RNAs and enzymes. Some are orthologous to previously identified genes in Archaea, Bacteria or in <it>Saccharomyces cerevisiae</it>, but several are original predictions.</p> <p>Conclusion</p> <p>The number of modifications in t+rRNAs in the halophilic archaeon is surprisingly low when compared with other Archaea or Bacteria, particularly the hyperthermophilic organisms. This may result from the specific lifestyle of halophiles that require high intracellular salt concentration for survival. This salt content could allow RNA to maintain its functional structural integrity with fewer modifications. We predict that the few modifications present must be particularly important for decoding, accuracy of translation or are modifications that cannot be functionally replaced by the electrostatic interactions provided by the surrounding salt-ions. This analysis also guides future experimental validation work aiming to complete the understanding of the function of RNA modifications in Archaeal translation.</p

MODOMICS: a database of RNA modification pathways

MODOMICS is the first comprehensive database resource for systems biology of RNA modification. It integrates information about the chemical structure of modified nucleosides, their localization in RNA sequences, pathways of their biosynthesis and enzymes that carry out the respective reactions. MODOMICS also provides literature information, and links to other databases, including the available protein sequence and structure data. The current list of modifications and pathways is comprehensive, while the dataset of enzymes is limited to Escherichia coli and Saccharomyces cerevisiae and sequence alignments are presented only for tRNAs from these organisms. RNAs and enzymes from other organisms will be included in the near future. MODOMICS can be queried by the type of nucleoside (e.g. A, G, C, U, I, m(1)A, nm(5)s(2)U, etc.), type of RNA, position of a particular nucleoside, type of reaction (e.g. methylation, thiolation, deamination, etc.) and name or sequence of an enzyme of interest. Options for data presentation include graphs of pathways involving the query nucleoside, multiple sequence alignments of RNA sequences and tabular forms with enzyme and literature data. The contents of MODOMICS can be accessed through the World Wide Web at

Formation of the conserved pseudouridine at position 55 in archaeal tRNA

Pseudouridine (Ψ) located at position 55 in tRNA is a nearly universally conserved RNA modification found in all three domains of life. This modification is catalyzed by TruB in bacteria and by Pus4 in eukaryotes, but so far the Ψ55 synthase has not been identified in archaea. In this work, we report the ability of two distinct pseudouridine synthases from the hyperthermophilic archaeon Pyrococcus furiosus to specifically modify U55 in tRNA in vitro. These enzymes are (pfu)Cbf5, a protein known to play a role in RNA-guided modification of rRNA, and (pfu)PsuX, a previously uncharacterized enzyme that is not a member of the TruB/Pus4/Cbf5 family of pseudouridine synthases. (pfu)PsuX is hereafter renamed (pfu)Pus10. Both enzymes specifically modify tRNA U55 in vitro but exhibit differences in substrate recognition. In addition, we find that in a heterologous in vivo system, (pfu)Pus10 efficiently complements an Escherichia coli strain deficient in the bacterial Ψ55 synthase TruB. These results indicate that it is probable that (pfu)Cbf5 or (pfu)Pus10 (or both) is responsible for the introduction of pseudouridine at U55 in tRNAs in archaea. While we cannot unequivocally assign the function from our results, both possibilities represent unexpected functions of these proteins as discussed herein

A single methyltransferase YefA (RlmCD) catalyses both m5U747 and m5U1939 modifications in Bacillus subtilis 23S rRNA

Methyltransferases that use S-adenosylmethionine (AdoMet) as a cofactor to catalyse 5-methyl uridine (m5U) formation in tRNAs and rRNAs are widespread in Bacteria and Eukaryota, and are also found in certain Archaea. These enzymes belong to the COG2265 cluster, and the Gram-negative bacterium Escherichia coli possesses three paralogues. These comprise the methyltransferases TrmA that targets U54 in tRNAs, RlmC that modifies U747 in 23S rRNA and RlmD that is specific for U1939 in 23S rRNA. The tRNAs and rRNAs of the Gram-positive bacterium Bacillus subtilis have the same three m5U modifications. However, as previously shown, the m5U54 modification in B. subtilis tRNAs is catalysed in a fundamentally different manner by the folate-dependent enzyme TrmFO, which is unrelated to the E. coli TrmA. Here, we show that methylation of U747 and U1939 in B. subtilis rRNA is catalysed by a single enzyme, YefA that is a COG2265 member. A recombinant version of YefA functions in an E. coli m5U-null mutant adding the same two rRNA methylations. The findings suggest that during evolution, COG2265 enzymes have undergone a series of changes in target specificity and that YefA is closer to an archetypical m5U methyltransferase. To reflect its dual specificity, YefA is renamed RlmCD