19 research outputs found
Ce que les bibliothécaires disent de leur quartier
Ce rapport contient les principaux Ă©lĂ©ments dâune enquĂȘte menĂ©e dans le rĂ©seau de la lecture publique de Plaine commune. Il rĂ©sulte principalement de lâanalyse de 75 entretiens approfondis - dâune durĂ©e dâentre 1h30 et 2h - rĂ©alisĂ©s auprĂšs de bibliothĂ©caires. La plupart de ces entretiens ont Ă©tĂ© rĂ©alisĂ©s entre le mois dâoctobre 2008 et le mois de juin 2009 dans les locaux des 23 bibliothĂšques du rĂ©seau et dans les 8 villes qui composent la communautĂ© dâagglomĂ©rations. Cette enquĂȘte fait partie dâun projet de recherche plus vaste mis en oeuvre par une Ă©quipe dâĂ©tudiants et de chercheurs du Centre de sociologie des pratiques et des reprĂ©sentations politiques (CSPRP, UniversitĂ© Paris Diderot â Paris 7) et de lâInstitut de recherche interdisciplinaire sur les enjeux sociaux (IRIS, Ecole des hautes Ă©tudes en sciences sociales). Les analyses et les interprĂ©tations auxquels les entretiens ont donnĂ© lieu sont Ă©galement le rĂ©sultat des observations de terrain, des entretiens et du travail documentaire rĂ©alisĂ© dans le cadre de cette recherche plus vaste. Lâobjet de cette recherche plus large est de comprendre les rapports entre les bibliothĂšques et leurs quartiers et, en arriĂšre plan, dâĂ©clairer le rapport des classes populaires Ă lâĂ©crit. Dans ce cadre, lâenquĂȘte auprĂšs des bibliothĂ©caires de Plaine Commune dont nous prĂ©sentons ici les principaux rĂ©sultats vise plus prĂ©cisĂ©ment Ă dĂ©crire les reprĂ©sentations que les personnels des bibliothĂšques se font de leurs missions et des quartiers dans lesquels ils travaillent
Les bibliothÚques populaires argentines, ou quand la promotion de la lecture est prise en charge par la « communauté »
Aujourdâhui, le territoire national argentin compte des bibliothĂšques publiques, privĂ©es et universitaires et environ 2 000 bibliothĂšques populaires. Ces diffĂ©rents statuts tĂ©moignent de lâexistence de diffĂ©rentes initiatives en faveur dâune promotion de la lecture : initiative publique ou privĂ©e. Nous entendons ici par « lecture publique » lâensemble des mesures politiques et institutionnelles dĂ©veloppĂ©es en faveur dâune promotion de la lecture et portĂ©es par les acteurs politiques (biblioth..
Mild stress conditions during laboratory culture promote the proliferation of mutations that negatively affect Sigma B activity in Listeria monocytogenes
In Listeria monocytogenes, the full details of how stress signals are integrated into the ÏB regulatory pathway are not yet available. To help shed light on this question, we investigated a collection of transposon mutants that were predicted to have compromised activity of the alternative sigma factor B (ÏB). These mutants were tested for acid tolerance, a trait that is known to be under ÏB regulation, and they were found to display increased acid sensitivity, similar to a mutant lacking ÏB (ÎsigB). The transposon insertions were confirmed by whole-genome sequencing, but in each case, the strains were also found to carry a frameshift mutation in the sigB operon. The changes were predicted to result in premature stop codons, with negative consequences for ÏB activation, independently of the transposon location. Reduced ÏB activation in these mutants was confirmed. Growth measurements under conditions similar to those used during the construction of the transposon library revealed that the frameshifted sigB operon alleles conferred a growth advantage at higher temperatures, during late exponential phase. Mixed-culture experiments at 42°C demonstrated that the loss of ÏB activity allowed mutants to take over a population of parental bacteria. Together, our results suggest that mutations affecting ÏB activity can arise during laboratory culture because of the growth advantage conferred by these mutations under mild stress conditions. The data highlight the significant cost of stress protection in this foodborne pathogen and emphasize the need for whole-genome sequence analysis of newly constructed strains to confirm the expected genotype.This project has received funding from the European Unionâs Horizon 2020 research-and-innovation program under Marie SkĆodowska-Curie grant agreement no. 721456. Jialun Wu was funded by the Department of Agriculture, Food and the Marine (17/F/244)
Pathogenicity and virulence of Listeria monocytogenes: A trip from environmental to medical microbiology
Listeria monocytogenes is a saprophytic gram-positive bacterium, and an opportunistic foodborne pathogen that can produce listeriosis in humans and animals. It has evolved an exceptional ability to adapt to stress conditions encountered in different environments, resulting in a ubiquitous distribution. Because some food preservation methods and disinfection protocols in foodprocessing environments cannot efficiently prevent contaminations, L. monocytogenes constitutes a threat to human health and a challenge to food safety. In the host, Listeria colonizes the gastrointestinal tract, crosses the intestinal barrier, and disseminates through the blood to target organs. In immunocompromised individuals, the elderly, and pregnant women, the pathogen can cross the blood-brain and placental barriers, leading to neurolisteriosis and materno-fetal listeriosis. Molecular and cell biology studies of infection have proven L. monocytogenes to be a versatile pathogen that deploys unique strategies to invade different cell types, survive and move inside the eukaryotic host cell, and spread from cell to cell. Here, we present the multifaceted Listeria life cycle from a comprehensive perspective. We discuss genetic features of pathogenic Listeria species, analyze factors involved in food contamination, and review bacterial strategies to tolerate stresses encountered both during food processing and along the hostâs gastrointestinal tract. Then we dissect hostâpathogen interactions underlying listerial pathogenesis in mammals from a cell biology and systemic point of view. Finally, we summarize the epidemiology, pathophysiology, and clinical features of listeriosis in humans and animals. This work aims to gather information from different fields crucial for a comprehensive understanding of the pathogenesis of L. monocytogenes
Des bibliothĂšques populaires Ă la lecture publique
Les changements politiques et socioculturels amĂšnent au xixe siĂšcle une demande croissante de lecture, quâelle soit instructive ou rĂ©crĂ©ative. Les bibliothĂšques dites « populaires » sont alors mises en place pour tenter de rĂ©pondre Ă ces besoins. Trop laĂŻques pour certains, trop clĂ©ricales pour dâautres, trop « populaires » enfin, leur histoire a fait lâobjet dâun profond oubli pendant la longue premiĂšre moitiĂ© du xxe siĂšcle. Qui Ă©taient les lecteurs de la France rurale, comment les publics cohabitaient-ils, pourquoi le service de prĂȘt de livres sâest-il progressivement rĂ©pandu, comment les autoritĂ©s considĂ©raient-elles ces nouvelles institutions⊠? Pour la premiĂšre fois, dans la continuitĂ© des travaux de NoĂ« Richter puis du colloque, en 1984, portĂ© par la BibliothĂšque des Amis de lâInstruction du IIIe arrondissement de Paris, cette nouvelle Ă©tude scientifique rend compte de ce corpus mĂ©connu des bibliothĂšques. Ă la fois analyse historique approfondie et investigations sociologiques sur les publics, Ă partir de lâexamen des archives de plusieurs Ă©tablissements français, cet ouvrage explore la naissance et le dĂ©veloppement des bibliothĂšques dites populaires en Belgique et en Grande-Bretagne et prĂ©sente une dĂ©clinaison de ce type dâĂ©tablissement dans lâArgentine dâaujourdâhui. Ă lâheure des interrogations sur lâĂ©volution du modĂšle des bibliothĂšques publiques, des questionnements sur leur rĂŽle social, cet ouvrage, dirigĂ© par AgnĂšs Sandras, historienne et conservatrice des bibliothĂšques Ă la BibliothĂšque nationale de France, rassemble les contributions dâauteurs de tous horizons (historiens, sociologues, personnels scientifiques des bibliothĂšques, doctorants et chercheurs confirmĂ©sâŠ), en posant les jalons dâune recherche sur la gĂ©nĂ©alogie de la lecture publique contemporaine
Dynamics of Listeria Monocytogenes Stressosome Proteins in Response to Osmotic Stress and the Eukaryotic Intracellular Niche
Tesis doctoral inĂ©dita leĂda en la Universidad AutĂłnoma de Madrid, Facultad de Ciencias, Departamento de BiologĂa Molecular. Fecha de lectura: 22-10-2020Esta tesis tiene embargado el acceso al texto completo hasta el 22-04-2022Listeria monocytogenes is a Gram-positive bacterial pathogen that withstands environmental
stress efficiently, both in non-host and host environments. Sigma B (SigB), a stress-responsive
transcriptional factor, is activated by a supra-macromolecular complex, the stressosome, to allow
reprogramming of gene expression for stress adaptation. The stressosome structure, inferred
from complexes assembled in vitro, consists of the core proteins RsbR (here renamed RsbR1), its
paralogues, RsbS and, the kinase RsbT. The active complex is proposed to be tethered to the
membrane and to support RsbR1/RsbS phosphorylation by RsbT and the subsequent release of
RsbT following signal perception. Despite the information obtained from structural analyses and
the protein-protein interactions characterized in vitro within the RsbR1-RsbS-RsbT complex, there
remains much to be learnt about the dynamics of these interactions and how they are modulated
by live cells in response to stress.
In this thesis, I have addressed in L. monocytogenes the subcellular location of the main
stressosome components, their interactions and the phosphorylation status in the
absence/presence of osmotic stress. Unexpectedly, some of these proteins were detected mostly
in the cytosol and with phosphorylation states that remained unaltered in response to
hyperosmolarity. The kinase activity of RsbT on RsbR1/RsbS and its requirement for maximal SigB
activation in response to osmotic stress were also demonstrated in vivo. Cytosolic RsbR1 interacts
with RsbT, while this interaction diminishes at the membrane when RsbR1 paralogues (RsbR2,
RsbR3 and RsbL) are present. These findings suggest that in vivo the active RsbR1-RsbS-RsbT
complex forms only transiently and that membrane-associated RsbR1 paralogues could modulate
its assembly.
This study also provides insights into the distribution of stressosome proteins during the
interaction of L. monocytogenes with the mammalian host. RsbR1, detected mostly in the cytosol
of bacteria grown in laboratory media, mobilized however to the membrane during replication of
the pathogen inside eukaryotic cells. Although in the context of infection the role of SigB was
previously reported only in the invasion of epithelial cells, my data support activation of SigB
in vivo during L. monocytogenes intracellular growth. This activation might be impeded by the
RsbR1 paralogues during the entry of epithelial cells.
The last chapter aimed to extend in L. monocytogenes the characterization of cell wall proteome
changes in response to osmotic stress and the role that SigB and the stressosome play in this
surface remodeling. Higher levels of certain surface proteins regulated by SigB were observed in
response to hyperosmolarity. These surface proteins as well as SigB and its regulators, RsbR1 and
RsbX, had strong influence on modelling the envelope architecture of L. monocytogen
The public reading to the test of the working classes district : survey in the public librairies of Seine-Saint-Denis
Cette thĂšse sâintĂ©resse aux bibliothĂšques publiques des quartiers populaires de la Seine-Saint-Denis. A partir dâune enquĂȘte ethnographique rĂ©alisĂ©e dans une bibliothĂšque publique dâun quartier populaire, la thĂšse analyse la politique de lecture publique depuis son Ă©laboration, jusquâĂ sa traduction par des acteurs â les bibliothĂ©caires â et sa rĂ©ception dans un territoire. Dans le territoire Ă©tudiĂ©, la lecture publique se trouve mise Ă lâĂ©preuve de plusieurs façons. La distance de la majoritĂ© de la population ainsi que des formes de conflictualitĂ© et de tensions diverses â conflits entre bibliothĂ©caires et publics, hostilitĂ©s Ă lâencontre des actions culturelles dĂ©veloppĂ©es par les bibliothĂšques, Ă©ventuels actes de dĂ©gradation volontaire dirigĂ©s contre les Ă©quipements â complexifient lâinscription locale de ces institutions culturelles. A ces problĂ©matiques locales sâajoutent des Ă©volutions spĂ©cifiques au champ culturel. Le contexte contemporain dâĂ©volution des pratiques et des lĂ©gitimitĂ©s culturelles affecte directement les bibliothĂ©caires et pose la question de leur lĂ©gitimitĂ© sociale. La thĂšse prĂ©sente comment les difficultĂ©s dâinscription territoriale des bibliothĂšques publiques s'enracinent dans l'histoire et les Ă©volutions des politiques de lecture publique d'un cĂŽtĂ© et des quartiers et des classes populaires de l'autre.The work of this thesis is focused on public libraries in the working classes district of the Seine-Saint-Denis. Based on an ethnographic survey in a public library in a working class district, the thesis analyzes the public reading policy since its development until his transposition by the librarians and its reception in a territory. In this region, public librairies are put to the test in many ways. The distance of the majority of the population and several conflicts and tensions - conflicts between librarians and public, hostility against cultural actions developed by the libraries, possible acts of voluntary malicious damage directed against the equipment, complicate the local integration of these cultural institutions. At these problems we can add specific changements of the cultural field. The actual context of the redefining of hierarchies and of the cultural legitimacy affects directly librarians and asks the question of their social legitimacy. The thesis presents how the territorial integration difficulties of public libraries are rooted in the history and evolution of public reading policy on one side and neighborhoods and working classes on the othe
Le 19e siĂšcle et les bibliothĂšques populaires argentines
BibliothĂšque populaire Entre Todos, Bella Vista, Buenos Aires, Argentine, septembre 2012 (photo : Charlotte Perrot-Dessaux) En 2010, le ministĂšre de lâEducation de lâArgentine publiait la premiĂšre enquĂȘte consacrĂ©e aux bibliothĂšques scolaires argentines ((Ministerio de Educacion, Las bibliotecas escolares en la Argentina : un diagnostico desde sus actores, SM de Ediciones, Mexico, 2010, disponible en ligne Ă lâadresse : http://www.bnm.me.gov.ar/redes_federales/estadistica/oei/docs/Bibliotecas..
Estallido, émeute, soulÚvement, révolte, piquetero
Commençons par interroger les connotations associĂ©es respectivement aux termes Ă©meute et estallido social, dans le contexte de lâhistoire rĂ©cente des mouvements de protestation en France et en Argentine. Nous analyserons ensuite la traductibilitĂ© des mots « émeute » et estallido. « Ămeute ». DâaprĂšs le dictionnaire français, Ă©meute correspond Ă un soulĂšvement populaire. Sâinscrivant dans lâespace urbain et plus prĂ©cisĂ©ment dans les quartiers populaires, lâĂ©meute a comme point de dĂ©part un Ă©vĂ©..
Chapitre xii. BibliothÚques en quartier populaire : un espace public conflictuel ?
En France, les gouvernements locaux profitent souvent des contrats de rénovation urbaine et des fonds dont ils disposent pour bùtir des bibliothÚques, et plus récemment des médiathÚques, dans les quartiers, en particulier les quartiers dits « difficiles ». Les municipalités pensent ainsi ouvrir un équipement prestigieux dans ces espaces relégués, perçu comme bénéfique sur au moins trois niveaux : comme outil de lien social, comme opportunité pour donner accÚs à la culture, et enfin comme « éq..