« Des mots pour la MEEAO » : poétiser et politiser la ville

Me fourrant dans la gorge mille crocs de bambou. Mille pieux d’oursin. C’est toi sale bout du monde. Sale bout de petit matin ; C’est toi sale haine. C’est toi poids de l’insulte et cent ans de coups de fouet. C’est toi cent ans de ma patience cent ans de mes soins juste à ne pas mourir. Rooh oh… » Aimé Césaire - Extrait de Cahier d’un retour au pays natal. Poème inscrit au pochoir sur l’une des fenêtres emmurées de l’immeuble de la MEEAO. En novembre 2010, le collectif artistique Paris Label..

« Des mots pour la MEEAO » : poétiser et politiser la ville

Me fourrant dans la gorge mille crocs de bambou. Mille pieux d’oursin. C’est toi sale bout du monde. Sale bout de petit matin ; C’est toi sale haine. C’est toi poids de l’insulte et cent ans de coups de fouet. C’est toi cent ans de ma patience cent ans de mes soins juste à ne pas mourir. Rooh oh… » Aimé Césaire - Extrait de Cahier d’un retour au pays natal. Poème inscrit au pochoir sur l’une des fenêtres emmurées de l’immeuble de la MEEAO. En novembre 2010, le collectif artistique Paris Label..

La Maison des étudiants des États d’Afrique de l’Ouest (MEEAO)

La Maison des étudiants des États d’Afrique de l’Ouest (MEEAO), aussi connue sous les noms de résidence Porte Dorée, résidence Poniatowski ou « Ponia », est un immeuble de type haussmannien situé à l’angle du 69, boulevard Poniatowski et du 2, rue Claude-Decaen, dans le quartier de la Porte Dorée, dans le 12e arrondissement de Paris. L’histoire de cet immeuble se confond avec l’histoire coloniale et postcoloniale. Il fut aussi, plus récemment, le théâtre de luttes locales pour les droits des ..

Regulation of virulence in Francisella tularensis by small non-coding RNAs

Using a cDNA cloning and sequencing approach we have shown that Francisella tularensis expresses homologues of several small RNAs
(sRNAs) that are well-conserved among diverse bacteria. We have also discovered two abundant putative sRNAs that share no sequence similarity or conserved genomic context with any previously annotated regulatory transcripts. Deletion of either of these two loci led to significant changes in the expression of several mRNAs that likely include the cognate target(s) of these sRNAs. Deletion of these sRNAs did not, however, significantly alter F. tularensis growth under various stress conditions in vitro, its replication in murine cells, or its ability to induce disease in a mouse model of F. tularensis infection

0106: Influence of the ratio of co-expressed cardiac connexins Cx43 and Cx45 in the formation of gap junction channels and their electrical properties

The cardiac action potential (AP) propagation is regulated to permit the coordinated and rhythmic atrial and ventricular contractions. This regulation requires several factors, especially gap junctions, which ensure a direct pathway for electrical and biochemical signaling. They are clusters of few to hundred intercellular gap junction channels (GJC) made of two hemichannels docked in the membrane of adjacent cells, which are composed of six connexins (Cxs). Their distinct electrical properties are a key factor regulating the propagation of the AP. Four cardiac Cxs, Cx40, Cx43, Cx45 and Cx30.2, exhibit specific patterns of expression that change in the healthy and diseased heart, which leads to different possible configurations of GJC. The aim of this study is to investigate the function of the distinct ratio of co-expressed Cxs in regulating the formation and function of GJC. Electrical properties of GJC (junctional coupling, voltage dependence, unitary conductance) are determined by performing electrical recordings on cell pair by applying the dual voltage-clamp method. Rat Liver Epithelial cells stably transfected to induce accurate Cx43:Cx45 ratios of 0 (single Cx43 expression), 0.5, 1 and 2, are used. The ongoing recordings show distinct electrical properties before and after the induction of Cx45: induction of Cx45 decreases the cell-to-cell coupling and rectifies the voltage dependence of GJC. Preliminary unitary recordings suggest a distinct formation of GJC of mixed Cx43/Cx45 composition in function of the Cx43:Cx45 ratio. Further investigations will provide better understanding on the distinct contributions of Cx43 and Cx45 in the GJC make-up, electrical properties and function of the Cx43/Cx45 expression pattern in regulating the cardiac impulse propagation in the healthy heart, and the pro-arrhythmic behavior in the diseased heart

A novel receptor – ligand pathway for entry of Francisella tularensis in monocyte-like THP-1 cells: interaction between surface nucleolin and bacterial elongation factor Tu

<p>Abstract</p> <p>Background</p> <p><it>Francisella tularensis</it>, the causative agent of tularemia, is one of the most infectious human bacterial pathogens. It is phagocytosed by immune cells, such as monocytes and macrophages. The precise mechanisms that initiate bacterial uptake have not yet been elucidated. Participation of C3, CR3, class A scavenger receptors and mannose receptor in bacterial uptake have been already reported. However, contribution of an additional, as-yet-unidentified receptor for <it>F. tularensis </it>internalization has been suggested.</p> <p>Results</p> <p>We show here that cell-surface expressed nucleolin is a receptor for <it>Francisella tularensis </it>Live Vaccine Strain (LVS) and promotes LVS binding and infection of human monocyte-like THP-1 cells. The HB-19 pseudopeptide that binds specifically carboxy-terminal RGG domain of nucleolin inhibits LVS binding and infection of monocyte-like THP-1 cells. In a pull-down assay, elongation factor Tu (EF-Tu), a GTP-binding protein involved in protein translation, usually found in cytoplasm, was recovered among LVS bacterial membrane proteins bound on RGG domain of nucleolin. A specific polyclonal murine antibody was raised against recombinant LVS EF-Tu. By fluorescence and electron microscopy experiments, we found that a fraction of EF-Tu could be detected at the bacterial surface. Anti-EF-Tu antibodies reduced LVS binding to monocyte-like THP-1 cells and impaired infection, even in absence of complement and complement receptors. Interaction between EF-Tu and nucleolin was illustrated by two different pull-down assays using recombinant EF-Tu proteins and either RGG domain of nucleolin or cell solubilized nucleolin.</p> <p>Discussion</p> <p>Altogether, our results demonstrate that the interaction between surface nucleolin and its bacterial ligand EF-Tu plays an important role in <it>Francisella tularensis </it>adhesion and entry process and may therefore facilitate invasion of host tissues. Since phagosomal escape and intra-cytosolic multiplication of LVS in infected monocytes are very similar to those of human pathogenic <it>F. tularensis </it>ssp <it>tularensis</it>, the mechanism of entry into monocyte-like THP-1 cells, involving interaction between EF-Tu and nucleolin, might be similar in the two subspecies. Thus, the use of either nucleolin-specific pseudopeptide HB-19 or recombinant EF-Tu could provide attractive therapeutic approaches for modulating <it>F. tularensis </it>infection.</p

Identification of trkH, Encoding a Potassium Uptake Protein Required for Francisella tularensis Systemic Dissemination in Mice

Francisella tularensis is a highly infectious bacterium causing the zoonotic disease tularaemia. During its infectious cycle, F. tularensis is not only exposed to the intracellular environment of macrophages but also resides transiently in extracellular compartments, in particular during its systemic dissemination. The screening of a bank of F. tularensis LVS transposon insertion mutants on chemically defined medium (CDM) led us to identify a gene, designated trkH, encoding a homolog of the potassium uptake permease TrkH. Inactivation of trkH impaired bacterial growth in CDM. Normal growth of the mutant was only restored when CDM was supplemented with potassium at high concentration. Strikingly, although not required for intracellular survival in cell culture models, TrkH appeared to be essential for bacterial virulence in the mouse. In vivo kinetics of bacterial dissemination revealed a severe defect of multiplication of the trkH mutant in the blood of infected animals. The trkH mutant also showed impaired growth in blood ex vivo. Genome sequence analyses suggest that the Trk system constitutes the unique functional active potassium transporter in both tularensis and holarctica subspecies. Hence, the impaired survival of the trkH mutant in vivo is likely to be due to its inability to survive in the low potassium environment (1–5 mM range) of the blood. This work unravels thus the importance of potassium acquisition in the extracellular phase of the F. tularensis infectious cycle. More generally, potassium could constitute an important mineral nutrient involved in other diseases linked to systemic dissemination of bacterial pathogens

Identification of small RNAs in Francisella tularensis

Background: Regulation of bacterial gene expression by small RNAs (sRNAs) have proved to be important for many biological processes. Francisella tularensis is a highly pathogenic Gram-negative bacterium that causes the disease tularaemia in humans and animals. Relatively little is known about the regulatory networks existing in this organism that allows it to survive in a wide array of environments and no sRNA regulators have been identified so far. Results: We have used a combination of experimental assays and in silico prediction to identify sRNAs in F. tularensis strain LVS. Using a cDNA cloning and sequencing approach we have shown that F. tularensis expresses homologues of several sRNAs that are well-conserved among diverse bacteria. We have also discovered two abundant putative sRNAs that share no sequence similarity or conserved genomic context with any previously annotated regulatory transcripts. Deletion of either of these two loci led to significant changes in the expression of several mRNAs that likely include the cognate target(s) of these sRNAs. Deletion of these sRNAs did not, however, significantly alter F. tularensis growth under various stress conditions in vitro, its replication in murine cells, or its ability to induce disease in a mouse model of F. tularensis infection. We also conducted a genome-wide in silico search for intergenic loci that suggests F. tularensis encodes several other sRNAs in addition to the sRNAs found in our experimental screen. Conclusion: Our findings suggest that F. tularensis encodes a significant number of non-coding regulatory RNAs, including members of well conserved families of structural and housekeeping RNAs and other poorly conserved transcripts that may have evolved more recently to help F. tularensis deal with the unique and diverse set of environments with which it must contend

Astrophysically Triggered Searches for Gravitational Waves: Status and Prospects

In gravitational-wave detection, special emphasis is put onto searches that focus on cosmic events detected by other types of astrophysical observatories. The astrophysical triggers, e.g. from gamma-ray and X-ray satellites, optical telescopes and neutrino observatories, provide a trigger time for analyzing gravitational wave data coincident with the event. In certain cases the expected frequency range, source energetics, directional and progenitor information is also available. Beyond allowing the recognition of gravitational waveforms with amplitudes closer to the noise floor of the detector, these triggered searches should also lead to rich science results even before the onset of Advanced LIGO. In this paper we provide a broad review of LIGO's astrophysically triggered searches and the sources they target

Zusammenfassung

N-Heterocyclic carbenes (NHCs) have been shown to be useful ligands for the Suzuki-Miyaura cross-coupling at low catalyst loadings. We now report that the commercially available and air-stable [Pd(IPr)(cin)Cl] pre-catalyst permits the formation of various functionalized biaryls from aryl chlorides and boronic acids (37 examples) under very mild conditions using a mixture of ethanol/water as solvent and an inorganic base