300 results on '"Rochex A"'
Search Results
252. Determination of Cellulose Surface Energy by Imbibition Experiments in Relation to Bacterial Adhesion.
- Author
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Pezron, Isabelle, Rochex, Alice, Lebeault, Jean‐Michel, and Clausse, Danièle
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BACTERIAL adhesion , *MICROBIAL contamination , *SURFACE energy , *CELLULOSE fibers , *CONSTITUTION of matter , *CELLULOSE - Abstract
Bacterial adhesion is an important initiating step of microbial contamination in the paper and board industry. The adhesion process results from interactions between the cell surface, the liquid, and the fibers. In this context, we determined the cellulose pulp surface energy to better understand these interactions. As contact angles cannot be directly measured on cellulose fibers, experiments involving liquid imbibition into cellulose pulp sheets were performed. The results were interpreted in terms of Lifshitz–van der Waals(γsLW), electron-donor(γs−), and electron-acceptor(γs+) components of the surface energy. Results evidenced that cellulose fiber surface is characterized by significant electron-donor capacity, as is the cell surface of the bacteria. These results suggests that hydrophobic, non-specific type of interactions between the cell surface and cellulose are involved in this case. [ABSTRACT FROM AUTHOR]
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- 2004
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253. Adhesion of aPseudomonas putidastrain isolated from a paper machine to cellulose fibres.
- Author
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Rochex, A., Lecouturier, D., Pezron, I., and Lebeault, J.-M.
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ADHESION ,CELLULOSE ,FIBERS ,PSEUDOMONAS ,PAPERMAKING machinery - Abstract
The adhesion to cellulose fibres of a strain ofPseudomonas putidaisolated from a paper machine was studied under different environmental conditions. The physicochemical properties of bothP. putidacells and cellulose fibres were also determined to better understand the adhesion phenomenon. Adhesion was rapid (1 min) and increased with time, cell concentration and temperature (from 25 to 40°C), indicating that bacterial adhesion to cellulose fibres is essentially governed by a physicochemical process. TheP. putidacell surface was negatively charged, as shown by electrophoretic mobility measurements, and was hydrophilic due to a strong electron-donor character, as shown by the microbial adhesion to solvents method. Cellulose fibres were shown to be hydrophilic by contact angle measurements using the capillary rise method. These results suggest the importance of Lewis acid-base interactions in the adhesion process. In various ionic solutions (NaCl, KCl, CaCl
2 and MgCl2 ), adhesion increased with increasing ionic strength up to 10-100 mM, indicating that, at low ionic strength, electrostatic interactions were involved in the adhesion process. An increase in the C/N ratio of the growth medium (from 5 to 90) decreased adhesion but this could not be related to changes in physicochemical properties, suggesting that other factors may be involved. In practice, temperature, ionic strength and nitrogen concentration must be taken into consideration to reduce bacterial contamination in the paper industry. [ABSTRACT FROM AUTHOR]- Published
- 2004
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254. A screen for modifiers of RacGAP(84C) gain-of-function in the Drosophila eye revealed the LIM kinase Cdi/TESK1 as a downstream effector of Rac1 during spermatogenesis.
- Author
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Raymond, Karine, Bergeret, Evelyne, Avet-Rochex, Amélie, Griffin-Shea, Ruth, and Fauvarque, Marie-Odile
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DROSOPHILA ,GAMETOGENESIS ,GERM cells ,SPERMATOGENESIS ,GENETICS ,ENDOCRINE glands ,MICROBIAL genetics ,AMINO acids - Abstract
In Drosophila, RotundRacGAP/RacGAP(84C) is critical to retinal organisation and spermatogenesis. We show that eye-directed expression of RacGAP(84C) or its GTPase activating protein (GAP) domain induces a dominant rough eye phenotype which we used as a starting point in a gain-of-function screen to identify new partners of RacGAP(84C). Proteins known to function in Ras, Rho and Rac signalling were identified confirming the essential role of RacGAP(84C) in crosstalk between GTPases. Other potential RacGAP(84C) partners identified by the screen are implicated in signal transduction, DNA remodelling, cytoskeletal organisation, membrane trafficking and spermatogenesis. This latter class includes the serine/threonine kinase Center divider (Cdi), which is homologous to the human LIM kinase, Testis specific kinase 1 (TESK1), involved in cytoskeleton control through Cofilin phosphorylation. Eye-directed expression of cdi strongly suppressed the phenotypes induced by either RacGAP(84C) gain-of-function or by the dominant negative form of Rac1, Rac1N17. These results are consistent with Cdi being a specific downstream target of Rac1. We showed that Rac1 and cdi are both expressed in Drosophila testis and that homozygous Rac1 mutants exhibit poor fertility that is further reduced by introducing a cdi loss-of-function mutation in trans. Thus, results from a misexpression screen in the eye led us to a putative novel Rac1-Cdi-Cofilin pathway, regulated by RacGAP(84C), coordinating Drosophila spermatogenesis. [ABSTRACT FROM AUTHOR]
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- 2004
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255. Ecole et savoir dans les banlieues... et ailleurs
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Bernard Lahire, Bernard Charlot, Elisabeth Bautier, and Jean-Yves Rochex
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Sociology and Political Science - Abstract
Comment l'ecole est-elle vecue par les enfants des banlieues ? Quels rapports l'eleve etablit-il avec le savoir ? Pourquoi seulement 37 des 71 collegiens d'une ZEP de Saint-Denis accedent-ils a la classe de seconde ? C'est sur ces questions que s'ouvre une longue enquete de Bernard Charlot, professeur des sciences de l'education, et de son equipe de Paris VIII. Suivis sur plusieurs annees, 300 adolescents de Saint-Denis, La Courneuve et Massy livrent un "bilan de savoir" et nous disent la cite, l'ecole, les pratiques des enseignants. Ces histoires scolaires remettent en cause la fatalite de l'echec ou de la reussite, chere aux theories du handicap socioculturel. Une synthese a mediter pour les futurs enseignants, les acteurs de la formation continue et de l'action sociale.
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- 1993
256. VYGOTSKY. Défectologie et déficience mentale. (TDB, Textes de base en psychologie) Koviljka BARISNIKOV Geneviève PETITPIERRE
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Rochex, Jean-Yves
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- 1995
257. Multiple Deficiency Disease with Allergy and Nutritional Enteritis 1
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Jesse L. Carr, Francis Rochex, and Alfred C. Reed
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medicine.medical_specialty ,Allergy ,Infectious Diseases ,business.industry ,Virology ,Deficiency disease ,medicine ,Parasitology ,medicine.disease ,business ,Dermatology ,Enteritis - Published
- 1943
258. Les sociétés d'assurances suisses dans la perspective de 1992
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Favre-Rochex, André
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- 1988
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259. Mikulicz's Disease: A Case Report
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Reed, Alfred C. and Rochex, Francis
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Clinical Notes and Case Reports - Published
- 1939
260. Alfred A. deLorimier, M.D.
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Rochex, Francis, primary
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- 1960
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261. Multiple Deficiency Disease with Allergy and Nutritional Enteritis 1
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Reed, Alfred C., primary, Rochex, Francis, additional, and Carr, Jesse L., additional
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- 1943
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262. Alfred A. deLorimier, M.D
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Francis Rochex
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business.industry ,Medicine ,Radiology, Nuclear Medicine and imaging ,business ,Humanities - Published
- 1960
263. Phenotypic and genomic comparison of Mycobacterium aurum and surrogate model species to Mycobacterium tuberculosis: implications for drug discovery.
- Author
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Namouchi, Amine, Cimino, Mena, Favre-Rochex, Sandrine, Charles, Patricia, and Gicquel, Brigitte
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MYCOBACTERIUM tuberculosis , *DRUG resistance in bacteria , *BACTERIAL genomes , *COMPARATIVE genomics , *ANTITUBERCULAR agents - Abstract
Background: Tuberculosis (TB) is caused by Mycobacterium tuberculosis and represents one of the major challenges facing drug discovery initiatives worldwide. The considerable rise in bacterial drug resistance in recent years has led to the need of new drugs and drug regimens. Model systems are regularly used to speed-up the drug discovery process and circumvent biosafety issues associated with manipulating M. tuberculosis. These include the use of strains such as Mycobacterium smegmatis and Mycobacterium marinum that can be handled in biosafety level 2 facilities, making high-throughput screening feasible. However, each of these model species have their own limitations. Results: We report and describe the first complete genome sequence of Mycobacterium aurum ATCC23366, an environmental mycobacterium that can also grow in the gut of humans and animals as part of the microbiota. This species shows a comparable resistance profile to that of M. tuberculosis for several anti-TB drugs. The aims of this study were to (i) determine the drug resistance profile of a recently proposed model species, Mycobacterium aurum, strain ATCC23366, for anti-TB drug discovery as well as Mycobacterium smegmatis and Mycobacterium marinum (ii) sequence and annotate the complete genome sequence of this species obtained using Pacific Bioscience technology (iii) perform comparative genomics analyses of the various surrogate strains with M. tuberculosis (iv) discuss how the choice of the surrogate model used for drug screening can affect the drug discovery process. Conclusions: We describe the complete genome sequence of M. aurum, a surrogate model for anti-tuberculosis drug discovery. Most of the genes already reported to be associated with drug resistance are shared between all the surrogate strains and M. tuberculosis. We consider that M. aurum might be used in high-throughput screening for tuberculosis drug discovery. We also highly recommend the use of different model species during the drug discovery screening process. [ABSTRACT FROM AUTHOR]
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- 2017
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264. Školní vzdělávání ve Francii
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Šťastný, Vít, Zuzana Svobodová, and Jean-Yves Rochex
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- 2017
265. Sweden: Priority Education Policies in Times of Decentralisation and Individualisation
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Francia, Guadalupe, Herrera, Lázaro Moreno, Demeuse, Marc, editor, Frandji, Daniel, editor, Greger, David, editor, and Rochex, Jean-Yves, editor
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- 2012
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266. Romania: A System in Evolution, Searching for Its Conceptual References
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Rus, Calin, Demeuse, Marc, editor, Frandji, Daniel, editor, Greger, David, editor, and Rochex, Jean-Yves, editor
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- 2012
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267. Priority Education Policies in the Czech Republic: Redesigning Equity Policies in the Post-Communist Transformation
- Author
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Greger, David, Levínská, Markéta, Smetáčková, Irena, Demeuse, Marc, editor, Frandji, Daniel, editor, Greger, David, editor, and Rochex, Jean-Yves, editor
- Published
- 2012
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268. Policy Interventions to Reduce Educational Inequalities - The Case of England, 1997–2010
- Author
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Antoniou, Lia, Dyson, Alan, Raffo, Carlo, Demeuse, Marc, editor, Frandji, Daniel, editor, Greger, David, editor, and Rochex, Jean-Yves, editor
- Published
- 2012
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269. Priority Education Policies in Belgium: Two Modes of Regulation of the Effects of a Market Logic
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Friant, Nathanaël, Demeuse, Marc, Aubert-Lotarski, Angeline, Nicaise, Idesbald, Demeuse, Marc, editor, Frandji, Daniel, editor, Greger, David, editor, and Rochex, Jean-Yves, editor
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- 2012
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270. Greece: On Mechanisms and Successive Programmes between Support and Innovation
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Varnava-Skoura, Gella, Vergidis, Dimitris, Kassimi, Chryssa, Demeuse, Marc, editor, Frandji, Daniel, editor, Greger, David, editor, and Rochex, Jean-Yves, editor
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- 2012
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271. Introduction: Towards a Comparison of Priority Education Policies in Europe
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Frandji, Daniel, Demeuse, Marc, editor, Frandji, Daniel, editor, Greger, David, editor, and Rochex, Jean-Yves, editor
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- 2012
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272. Priority education policies in Belgium: two modes of regulation of the effects of a market logic
- Author
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Marc Demeuse, Idesbald Nicaise, Angeline Aubert-Lotarski, Nathanaël Friant, Institut d'Administration scolaire (INAS), Université de Mons (UMons), HIVA (Higher Inst. for Labour Studies) / Dept of Educational Sciences (HIVA), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Marc Demeuse, Daniel Frandji, David Greger, Jean-Yves Rochex, EuroPEP, Demeuse, Marc, and Marc Demeuse, Daniel Frandji, David Greger, Jean-Yves Rochex
- Subjects
education policy ,Secondary education ,business.industry ,4. Education ,[SHS.EDU]Humanities and Social Sciences/Education ,05 social sciences ,[SHS.EDU] Humanities and Social Sciences/Education ,050301 education ,050801 communication & media studies ,Scientific literature ,Public relations ,Equal opportunity ,language.human_language ,Flemish ,0508 media and communications ,Political science ,language ,Market logic ,Education policy ,business ,0503 education ,Competence (human resources) ,Federal state - Abstract
International audience; An important feature of the Belgian context is the 'communautarisation'2 of education policies. Since 1989 teaching has fallen within the competence of the communities, whereas until then it came under the Federal state. It is the three language-based communities (the French-, Flemish- and German-speaking communities) that manage similar but completely independent education systems, each covering part of the country3. In this chapter we will base our account on the French and Flemish communities. The first part deals with the general context of the education systems of these two communities and recounts their joint move towards equity up to 1989. The second part is centred on the priority education policies in the French Community. The targeted populations and the actions prescribed are analysed on the basis of official documents. Their effective implementation and the evaluation of their effects (whether desired or not) is then discussed on the basis of research and the scientific literature available. The third part of this chapter analyses, in the same way, the priority education policies in the Flemish Community. The chapter concludes, as a summary, by examining the similarities and divergences which exist between the two communities.
- Published
- 2012
273. Peut-on vraiment évaluer les politiques d'éducation prioritaire en Europe
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Demeuse, Marc, Institut d'Administration scolaire (INAS), Université de Mons (UMons), Marc Demeuse, Daniel Frandji, David Greger, Jean-Yves Rochex, EuroPEP, Demeuse, Marc, and Marc Demeuse, Daniel Frandji, David Greger, Jean-Yves Rochex
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[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,évaluation des politiques éducatives ,éducation prioritaire - Abstract
International audience; Pour répondre à la question introduite par le titre de ce chapitre, il faut envisager à la fois l'angle technique (dispose-t-on les moyens d'évaluer ce type de politiques ?) et l'angle de l'autorité et des usages (s'autorise-t-on à évaluer ce type de politiques ? que fait-on de ces évaluations?). C'est ce que feront respectivement les auteurs de deux chapitres qui vont suivre. Le premier chapitre (Demeuse, Demierbe et Friant) proposera de clarifier l'analyse, suggérant un modèle global qui sera appliqué à certaines des PEP qui ont été analysées dans le premier ouvrage (Demeuse et al. 2008). Le second chapitre (Broccolichi) interrogera les mésusages et les lacunes dans l'évaluation de ces mêmes politiques. Dans ce chapitre introductif, nous tenterons de mieux définir ce que recouvre le concept d'évaluation et d'apporter quelques précisions à propos des méthodes d'évaluation dans le contexte des politiques d'éducation prioritaire.
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- 2011
274. 'Groupes à risque', 'besoins spécifiques' : raison gestionnaire et ghetto épistémologique au service d'une redéfinition scolaire
- Author
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Daniel Frandji, Triangle : action, discours, pensée politique et économique (TRIANGLE), Centre National de la Recherche Scientifique (CNRS)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), Demeuse, Marc, Frandji, Daniel, Greger, David, Rochex, Jean-Yves, École normale supérieure de Lyon (ENS de Lyon)-Université Lumière - Lyon 2 (UL2)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Frandji, Daniel, Demeuse, Marc, Greger, David, and Rochex, Jean-Yves
- Subjects
Education Special ,050402 sociology ,[SHS.SOCIO] Humanities and Social Sciences/Sociology ,JNM ,politiques d'éducation prioritaire ,Political Science ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,raisonnement gestionnaire ,éducation prioritaire ,égalité scolaire ,0504 sociology ,politique éducative ,EDU015000 ,Sociologie de la connaissance ,Ghetto épistémologique ,[SHS.SOCIO]Humanities and Social Sciences/Sociology ,Marquage social ,05 social sciences ,050301 education ,enseignement ,échec scolaire ,[SHS.SCIPO]Humanities and Social Sciences/Political science ,0503 education ,[SHS.SCIPO] Humanities and Social Sciences/Political science ,Catégories cognitives - Abstract
La comparaison des politiques d’éducation prioritaire nous confronte à deux catégories générales ou « métacatégories » désignant leurs publics bénéficiaires, à savoir celle des « groupes à risque », ainsi que celle des élèves à « besoins éducatifs particuliers » ou « besoins éducatifs spécifiques » (special educational needs). Nous employons ici le terme de métacatégorie tel qu’il est parfois utilisé, simplement pour signifier le caractère englobant de ces deux notions classificatrices qui re...
- Published
- 2011
275. Un laboratoire des 'nouvelles politiques éducatives' : quelle priorité, quelles figures de justice ?
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Frandji, Daniel, Triangle : action, discours, pensée politique et économique (TRIANGLE), École normale supérieure de Lyon (ENS de Lyon)-Université Lumière - Lyon 2 (UL2)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Demeuse, Marc, Frandji, Daniel, Greger, David, Rochex, Jean-Yves, Centre National de la Recherche Scientifique (CNRS)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), Frandji, Daniel, Demeuse, Marc, Greger, David, and Rochex, Jean-Yves
- Subjects
[SHS.SOCIO]Humanities and Social Sciences/Sociology ,[SHS.SOCIO] Humanities and Social Sciences/Sociology ,politiques d'éducation prioritaire ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,politiques éducatives ,Justice sociale ,Education comparée ,Sociologie de l'éducation ,Sociologie du curriculum et de la pédagogie ,[SHS.SCIPO]Humanities and Social Sciences/Political science ,Sociologie de la connaissance ,Savoirs scolaires ,Normativité ,[SHS.SCIPO] Humanities and Social Sciences/Political science ,Compensation ,Socio-histoire - Published
- 2011
276. Pluralité des catégories de 'cibles', tensions et implicites dans les élaborations
- Author
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Jean-Claude Émin, Benjamin Moignard, Daniel Frandji, Choukri Ben Ayed, Anneloes Vandenbroucke, Triangle : action, discours, pensée politique et économique (TRIANGLE), Centre National de la Recherche Scientifique (CNRS)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), Groupe de Recherches et d'Etudes Sociologiques du Centre-Ouest (GRESCO), Université de Limoges (UNILIM)-Université de Poitiers-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), HIVA-K.U.Leuven - Research Institute for Work and Society (HIVA), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Demeuse, Marc, Frandji, Daniel, Greger, David, Rochex, Jean-Yves, École normale supérieure de Lyon (ENS de Lyon)-Université Lumière - Lyon 2 (UL2)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Frandji, Daniel, Demeuse, Marc, Greger, David, and Rochex, Jean-Yves
- Subjects
Education Special ,[SHS.SOCIO]Humanities and Social Sciences/Sociology ,[SHS.SOCIO] Humanities and Social Sciences/Sociology ,JNM ,politiques d'éducation prioritaire ,Political Science ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,05 social sciences ,enseignement ,050301 education ,050109 social psychology ,échec scolaire ,éducation prioritaire ,[SHS.SCIPO]Humanities and Social Sciences/Political science ,égalité scolaire ,politique éducative ,EDU015000 ,0501 psychology and cognitive sciences ,ciblage ,[SHS.SCIPO] Humanities and Social Sciences/Political science ,0503 education - Abstract
Convergence vers un espace scolaire fragmenté Le premier constat qui s’impose à l’analyse est donc celui de la grande diversité et de la pluralité des catégories définissant les « cibles » des PEP dans les différents pays. Nous employons ce terme de « ciblage » car il est souvent usité, malgré la métaphore guerrière ou publicitaire du terme (de même qu’en anglais : targeting). Le terme de « bénéficiaire » tend parfois ainsi à lui être préféré. Mais celui-ci connote aussi des caractéristiques ...
- Published
- 2011
277. Les frontières des PEP comme élaboration sociale complexe
- Author
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Frandji, Daniel, Triangle : action, discours, pensée politique et économique (TRIANGLE), Centre National de la Recherche Scientifique (CNRS)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), Demeuse, Marc, Frandji, Daniel, Greger, David, Rochex, Jean-Yves, Frandji, Daniel, Demeuse, Marc, Greger, David, Rochex, Jean-Yves, École normale supérieure de Lyon (ENS de Lyon)-Université Lumière - Lyon 2 (UL2)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), and Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[SHS.SOCIO]Humanities and Social Sciences/Sociology ,[SHS.SOCIO] Humanities and Social Sciences/Sociology ,politiques d'éducation prioritaire ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,[SHS.SCIPO] Humanities and Social Sciences/Political science ,[SHS.SCIPO]Humanities and Social Sciences/Political science - Published
- 2011
278. Nitazoxanide Analogs Require Nitroreduction for Antimicrobial Activity in Mycobacterium smegmatis.
- Author
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Buchieri, Maria V., Cimino, Mena, Rebollo-Ramirez, Sonia, Beauvineau, Claire, Cascioferro, Alessandro, Favre-Rochex, Sandrine, Helynck, Olivier, Naud-Martin, Delphine, Larrouy-Maumus, Gerald, Munier-Lehmann, Hélène, and Gicquel, Brigitte
- Subjects
- *
MYCOBACTERIUM smegmatis , *ANTI-infective agents , *HIGH throughput screening (Drug development) , *NITROREDUCTASES , *NATURAL immunity - Abstract
In this study, we aimed to decipher the natural resistance mechanisms of mycobacteria against novel compounds isolated by whole-cell-based high-throughput screening (HTS). We identified active compounds using Mycobacterium aurum. Further analyses were performed to determine the resistance mechanism of M. smegmatis against one hit, 3-bromo-N-(5-nitrothiazol-2-yl)-4-propoxybenzamide (3), which turned out to be an analog of the drug nitazoxanide (1). We found that the repression of the gene nfnB coding for the nitroreductase NfnB was responsible for the natural resistance of M. smegmatis against 3. The overexpression of nfnB resulted in sensitivity of M. smegmatis to 3. This compound must be metabolized into hydroxylamine intermediate for exhibiting antibacterial activity. Thus, we describe, for the first time, the activity of a mycobacterial nitroreductase against 1 analogs, highlighting the differences in the metabolism of nitro compounds among mycobacterial species and emphasizing the potential of nitro drugs as antibacterials in various bacterial species. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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279. France: Crisis in the Schools
- Author
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Rochex, Jean-Yves
- Published
- 1991
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280. Towards a comparison of Priority Education Policies in Europe
- Author
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Frandji, Daniel, Triangle : action, discours, pensée politique et économique (TRIANGLE), Centre National de la Recherche Scientifique (CNRS)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Université Lumière - Lyon 2 (UL2)-École normale supérieure - Lyon (ENS Lyon), Demeuse, Marc, Frandji, Daniel, Greger, David, Rochex, Jean-Yves, École normale supérieure de Lyon (ENS de Lyon)-Université Lumière - Lyon 2 (UL2)-Sciences Po Lyon - Institut d'études politiques de Lyon (IEP Lyon), and Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Europe ,education ,EuroPEP ,inequalities ,public policy ,[SHS.EDU]Humanities and Social Sciences/Education ,Priority Education Policies ,[SHS.SCIPO]Humanities and Social Sciences/Political science - Published
- 2012
281. Des savoirs transparents dans le travail des professeurs à l'école primaire
- Author
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Margolinas, Claire, Laparra, Marceline, Activité, Connaissance, Transmission, éducation (ACTé), Université Blaise Pascal - Clermont-Ferrand 2 (UBP), Centre de Recherche sur les Médiations (Crem), Université de Lorraine (UL), J.-Y. Rochex, J. Crinon, and Margolinas, Claire
- Subjects
situation ordinaire ,étude de cas ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,inégalité scolaire ,savoir transparent ,situation de l'élève ,situation du professeur - Abstract
Notre recherche s'applique à élucider comment les processus de production des inégalités scolaires se constituent et se renforcent au sein même des interactions didactiques quotidiennes, à l'insu des acteurs de ces interactions. Pour étudier cette question, nous avons suivi de 2004 à 2006 une classe de grande section (élèves de 5 et 6 ans) à l'intérieur de laquelle nous nous sommes plus particulièrement intéressées à six élèves, puis nous avons suivi les mêmes élèves en cours préparatoire l'année suivante. Nous avons ainsi recueilli plus de soixante heures de vidéos, ainsi que de très nombreuses reproductions de travaux d'élèves ; la moitié environ des vidéos a été transcrite. Il s'agit de séances soit de mathématiques, soit de lecture-écriture. Les deux classes ainsi observées sont situées en zone d'éducation prioritaire dans une petite ville à forte tradition ouvrière du Puy-de-Dôme. Les élèves présentent une très grande homogénéité socioculturelle : ils appartiennent quasiment tous à des milieux populaires, défavorisés au plan économique. L'ensemble du corpus sur lequel nous avons travaillé nous a permis de comprendre le caractère récurent des phénomènes qui sont l'objet de ce chapitre, nous avons fait le choix ici de ne pas nous appuyer sur une analyse de cas. C'est dans un autre chapitre que nous ferons référence à un élément du corpus d'une façon plus détaillée. Dans ce chapitre, nous essaierons tout d'abord de restituer en première approche quels peuvent être les points de vue du maitre et des élèves dans les situations ordinaires de l'école primaire ; il s'agira ensuite de montrer que, depuis la position du professeur, certains éléments de la situation des élèves ne sont pas vraiment visibles, sans être totalement ignorés, ils sont comme " transparents " ; nous questionnerons enfin la place des savoirs dans le travail du professeur.
- Published
- 2011
282. Sociologie des dispositifs pédagogiques : structuration matérielle et technique, conceptions sociales de l'élève et apprentissages inégaux
- Author
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Bonnéry, Stéphane, Bonnéry, Stéphane, Rochex Jean-Yves & Crinon Jacques, Centre interdisciplinaire de recherche, culture, éducation, formation, travail (CIRCEFT), and Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)
- Subjects
dispositifs pédagogiques ,postures d'apprentissage ,[SHS.SOCIO]Humanities and Social Sciences/Sociology ,[SHS.SOCIO] Humanities and Social Sciences/Sociology ,[SHS.EDU]Humanities and Social Sciences/Education ,sociologie de l'éducation ,pratiques pédagogiques ,[SHS.EDU] Humanities and Social Sciences/Education ,techniques d'apprentissage ,ergonomie - Published
- 2011
283. Quand les maîtres contribuent à leur insu à renforcer les difficultés des élèves
- Author
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Laparra, Marceline, Margolinas, Claire, Centre de Recherche sur les Médiations (Crem), Université de Lorraine (UL), Activité, Connaissance, Transmission, éducation (ACTé), Université Blaise Pascal - Clermont-Ferrand 2 (UBP), J.-Y. Rochex & J. Crinon, and Margolinas, Claire
- Subjects
situation ordinaire ,étude de cas ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,inégalité scolaire ,savoir transparent ,situation de l'élève ,situation du professeur - Abstract
Notre recherche s'applique à élucider comment les processus de production des inégalités scolaires se constituent et se renforcent au sein même des interactions didactiques quotidiennes, à l'insu des acteurs de ces interactions. Pour étudier cette question, nous avons suivi de 2004 à 2006 une classe de grande section (élèves de 5 et 6 ans) à l'intérieur de laquelle nous nous sommes plus particulièrement intéressées à six élèves, puis nous avons suivi les mêmes élèves en cours préparatoire l'année suivante. Nous avons ainsi recueilli plus de soixante heures de vidéos, ainsi que de très nombreuses reproductions de travaux d'élèves ; la moitié environ des vidéos a été transcrite. Il s'agit de séances soit de mathématiques, soit de lecture-écriture. Les deux classes ainsi observées sont situées en zone d'éducation prioritaire dans une petite ville à forte tradition ouvrière du Puy-de-Dôme. Les élèves présentent une très grande homogénéité socioculturelle : ils appartiennent quasiment tous à des milieux populaires, défavorisés au plan économique. L'ensemble du corpus sur lequel nous avons travaillé nous a permis de comprendre le caractère récurent des phénomènes qui sont l'objet de ce chapitre, nous avons fait le choix ici de ne pas nous appuyer sur une analyse de cas. Dans ce chapitre, nous essaierons tout d'abord de restituer en première approche quels peuvent être les points de vue du maitre et des élèves dans les situations ordinaires de l'école primaire ; il s'agira ensuite de montrer que, depuis la position du professeur, certains éléments de la situation des élèves ne sont pas vraiment visibles, sans être totalement ignorés, ils sont comme " transparents " ; nous questionnerons enfin la place des savoirs dans le travail du professeur.
- Published
- 2011
284. Pluralité et hétérogénéité des catégories de ciblage
- Author
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Ben Ayed, Choukri, Frandji, Daniel, Moignard, Benjamin, Anneloes Vandenbroucke, Frandji, Daniel, Pinceman, Jean-Marie, Demeuse, Marc, Greger, David, and Rochex, Jean-Yves
- Abstract
Dit hoofdstuk is een onderdeel van het tweede volume van de wetenschappelijke rapportering voor het project Europep - Comparaison des politiques d’Éducation prioritaire en Europe. De titel van dit tweede volume luidt 'Éléments d’une analyse transversale: formes de ciblage, action, évaluation'. no ISBN ispartof: Comparaison des politiques d'Education prioritaire en Europe. Rapport scientifique Vol. 2 - Eléments d'une analyse transversale: formes de ciblage, action, évaluation pages:359-378 ispartof: pages:359-378 nrpages: 13-31 status: published
- Published
- 2009
285. Contribution a la compréhension des processus de construction identitaire au travail des enseignants d'EPS en collège
- Author
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Waltz, Arnaud, Moisan, Victor, Centre interdisciplinaire de recherche, culture, éducation, formation, travail (CIRCEFT), Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Université Paris VIII Vincennes-Saint Denis, and Jean-Yves ROCHEX
- Subjects
Didactique ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,Professeurs d'éducation physique ,France ,Éducation physique - Abstract
The study of the practices of intervention convened in this research contributes to the understanding of the processes involved in the development of Secondary school Physical Education teachers' identity at work. Whether they are specialists in the taught APSA or not, the activity vis-a-vis with the pupils of the "beginner", "experienced" and "expert" is not very comparable and tends to deviate from the common framework of the disciplinary project. In the implicit hierarchy and the power plays which are established between the three levels of the professional experience, the "experts", whose interventions constitute strong identity reference marks, seem to relay at the local level the institutional authority. During his/her identity construction, the "experienced" cultivates the doubt whereas the "beginner", vis-a-vis with the difficulties which he/she encounters, develops a confidence in the future. Lastly, the identity question renews the debates and traditional oppositions between the various didactic schools of thought in PE., L'étude des pratiques d'intervention convoquées dans cette recherche contribue à la compréhension des processus de construction de l'identité au travail des enseignants d'EPS en collège.Qu'ils soient ou non spécialistes des APSA enseignées, l'activité face aux élèves des " novice ", " expérimenté " et " expert " est peu comparable et tend à s'écarter du cadre commun du projet disciplinaire.Dans la hiérarchie implicite et les jeux de pouvoir qui s'établissent entre les trois niveaux de l'expérience professionnelle, les " experts ", dont les interventions constituent des repères identitaires forts, semblent relayer au niveau local l'autorité Institutionnelle. Au cours de sa construction identitaire, " l'expérimenté " cultive le doute alors que le " novice ", face aux difficultés qu'il rencontre, développe une confiance en l'avenir.Enfin, la question identitaire renouvelle les débats et oppositions traditionnelles entre les différents courants didactiques en EPS
- Published
- 2007
286. Vygotski pour penser l’intériorisation socialement différenciée de la culture à l’école primaire
- Author
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Julien Netter, Éducation et scolarisation (ESCOL), Centre interdisciplinaire de recherche, culture, éducation, formation, travail (CIRCEFT), Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Jean-Yves Rochex, Christophe Joigneaux, Julien Netter, and Netter, Julien
- Subjects
[SHS.PSY] Humanities and Social Sciences/Psychology ,inégalité sociale ,[SHS.SOCIO]Humanities and Social Sciences/Sociology ,[SHS.SOCIO] Humanities and Social Sciences/Sociology ,[SHS.EDU]Humanities and Social Sciences/Education ,[SHS.EDU] Humanities and Social Sciences/Education ,[SHS.PSY]Humanities and Social Sciences/Psychology ,animateur ,art dramatique ,enseignement primaire ,apprentissage avec approches multiples - Abstract
International audience; Dans « histoire du développement des fonctions psychiques supérieures », Vygotski pose une thèse qu’il reprendra dans « pensée et langage » (1997) selon laquelle le développement et l’organisation des fonctions psychiques supérieures résulte d’une intériorisation des rapports sociaux. Ainsi selon lui, le développement ne procède pas de l’individu vers la société mais à l’inverse de la société vers l’individu qui en incorpore l’essence, la culture étant d’une part une image des rapports de force réels entre les individus, ce qui fait dire à Vygotski (2014) que « tout le culturel est social » (p. 286), et d’autre part l’instrument de cette intériorisation qui devient « partie inaliénable de la personnalité » (p. 261).L’apprentissage et l’utilisation de l’écrit constituent le mode d’intériorisation du social privilégié par l’école, qui tend à occulter les rapports sociaux liés à la littératie pour mettre en exergue l’universalité des savoirs et la relation maitre-élèves. La communication entend s’appuyer sur la description que Vygotski esquisse du jeu symbolique comme « préhistoire du développement du langage écrit » (Vygotski, 2014) et sur la proximité qu’il établit entre le jeu et l’art (Vygotski, 2005) pour étudier la prise en compte par l’école de systèmes de signes intermédiaires ou alternatifs permettant l’accompagnement des enfants vers la maîtrise de l’écrit. A partir des analyses d’une recherche ethnographique d’orientation sociologique menée pendant plus d’un an dans sept écoles élémentaires parisiennes socialement contrastées sur les temps scolaires et périscolaires, on considérera l’utilisation ordinaire du théâtre à l’école. Plusieurs points de comparaison et de discordance entre le jeu symbolique et le théâtre seront évoqués. Puis on s’interrogera sur la façon dont deux séances de théâtre mènent ou non au développement de système de signes alternatifs à l’écrit. On verra qu’un tel développement peut être observé pour certains élèves dans certaines conditions, mais on montrera qu’il est confronté dans l’école contemporaine à deux écueils symétriques. D’une part, en classe, l’importance de la compétition scolaire et des relations maitre/élèves complique le recours à une forme théâtrale qui suppose au contraire pour les élèves de se déprendre des relations verticales immédiates par lesquelles ils sont tenus et de laisser une place aux interactions entre pairs. Faute de cette latitude, les élèves sont conduits à établir directement la correspondance entre une situation abstraite et son expression littéraciée, sans système de signes alternatif. D’autre part, dans les temps périscolaires où ce recours est plus facile, les élèves se révèlent inégaux face à l’injonction à « jouer » une scène. Ils ne disposent en effet pas d’une égale maîtrise des éléments langagiers et corporels requis pour y parvenir, ni d’une même familiarité avec la situation de jeu théâtral et avec l’idée d’une distinction entre le personnage et eux. En outre, les pratiques des encadrants non-enseignants, peu orientées vers les apprentissages, conduisent les élèves à adopter des attitudes différenciées. Certains s’engagent dans une logique de « jeu sérieux » socialement marquée (Lemêtre, 2015) qui les engage à mettre à profit ce qu’ils identifient comme des occasions d’établir un lien avec la classe quand d’autres, percevant mal les enjeux de l’activité, finissent par en rendre le déroulement chaotique et peu scolairement profitable. Le texte sera donc l’occasion de réfléchir sur la construction des inégalités dans l’école française en posant la constitution des systèmes de signes comme un objet d’observation central, mais également de s’interroger sur la façon dont des apports de psychologie et de sociologie peuvent s’articuler pour éclairer plus efficacement cette construction.
287. Lipopeptide culture filtrates from Bacillus spp. provide effective protection to wheat against the foliar pathogen Zymoseptoria tritici.
- Author
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El Arbi A, Arnauld S, Chataigné G, Lecouturier D, Bricout A, Gharsallah N, Jacques P, Siah A, and Rochex A
- Subjects
- Plant Diseases prevention & control, Plant Diseases microbiology, Lipopeptides pharmacology, Triticum microbiology, Bacillus, Ascomycota
- Abstract
Aims: Biocontrol products based on microorganisms and natural substances are promising alternatives to chemical pesticides that could contribute to develop a more sustainable agriculture. Here, we investigated the potential of cell-free culture filtrates (CFCFs) from two strains of the Bacillus subtilis group to inhibit Zymoseptoria tritici, a major fungal pathogen of wheat., Methods and Results: Foliar application of CFCFs from Bacillus velezensis GA1 and Bacillus sp. III1 on wheat seedlings in a greenhouse strongly reduced Z. tritici disease severity (>90%). In vitro bioassays showed that CFCFs completely inhibited the spore germination and fungal growth (100%). In planta cytological investigations revealed a significant impact of the treatments on both spore germination (∼40% inhibition) and fungal growth of Z. tritici (>80% inhibition). High Performance Liquid Chromatography (HPLC) analysis showed that the Bacillus strains displayed different lipopeptide profiles. The CFCF obtained from Bacillus GA1 contained 90 mg l-1 of iturin A + surfactins + fengycins and the CFCF obtained from Bacillus sp. III1 contained 25 mg l-1 of mojavensin A (iturin family) + surfactins + fengycins., Conclusions: Strains of the B. subtilis group producing different iturins could provide several CFCF-based solutions for the biocontrol of Z. tritici., (© The Author(s) 2023. Published by Oxford University Press on behalf of Applied Microbiology International.)
- Published
- 2024
- Full Text
- View/download PDF
288. The Diversity of Lipopeptides in the Pseudomonas syringae Complex Parallels Phylogeny and Sheds Light on Structural Diversification during Evolutionary History.
- Author
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Bricout A, Morris CE, Chandeysson C, Duban M, Boistel C, Chataigné G, Lecouturier D, Jacques P, Leclère V, and Rochex A
- Subjects
- Phylogeny, Bacteria, Mass Spectrometry, Pseudomonas syringae genetics, Lipopeptides
- Abstract
Pseudomonas spp. colonize diverse aquatic and terrestrial habitats and produce a wide variety of secondary metabolites, including lipopeptides. However, previous studies have often examined a limited number of lipopeptide-producing strains. In this study, we performed a systematic analysis of lipopeptide production across a wide data set of strains of the Pseudomonas syringae complex (724) by using a combined bioinformatics, mass spectrometry, and phylogenetics approach. The large P. syringae complex, which is composed of 13 phylogroups, is known to produce factins (including syringafactin-like lipopeptides), mycins (including syringomycin-like lipopeptides), and peptins (such as syringopeptins). We found that 80.8% of P. syringae strains produced lipopeptides and that factins were the most frequently produced (by 96% of the producing strains). P. syringae strains were either factin monoproducers or factin, mycin, and peptin coproducers or lipopeptide nonproducers in relation to their phylogenetic group. Our analyses led to the discovery of 42 new lipopeptides, bringing the number of lipopeptides identified in the P. syringae complex to 75. We also highlighted that factins have high structural resemblance and are widely distributed among the P. syringae complex, while mycins and peptins are highly structurally diverse and patchily distributed. IMPORTANCE This study provides an insight into the P. syringae metabolome that emphasizes the high diversity of lipopeptides produced within the P. syringae complex. The production profiles of strains are closely related to their phylogenetic classification, indicating that structural diversification of lipopeptides parallels the phylogeny of this bacterial complex, thereby further illustrating the inherent importance of lipopeptides in the ecology of this group of bacteria throughout its evolutionary history. Furthermore, this overview of P. syringae lipopeptides led us to propose a refined classification that could be extended to the lipopeptides produced by other bacterial groups.
- Published
- 2022
- Full Text
- View/download PDF
289. Rhamnolipids and fengycins, very promising amphiphilic antifungal compounds from bacteria secretomes, act on Sclerotiniaceae fungi through different mechanisms.
- Author
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Botcazon C, Bergia T, Lecouturier D, Dupuis C, Rochex A, Acket S, Nicot P, Leclère V, Sarazin C, and Rippa S
- Abstract
Rhamnolipids (RLs) and fengycins (FGs) are amphiphilic lipid compounds from bacteria secretomes proposed to replace synthetic pesticides for crop protection. They both display plant defense triggering properties and direct antimicrobial activities. In particular, they have well reported antifungal effects against phytopathogenic fungi. RLs and FGs are considered to act through a direct interaction with membrane lipids and a destabilization of microorganism plasma membrane, thereby limiting the risk of resistance emergence. The main objective of this work was to gain insights in the antimycelial mode of action of these metabolites to promote them as environment and human health friendly biocontrol solutions. Their biocidal effects were studied on two Sclerotiniaceae fungi responsible for diseases in numerous plant species worldwide. We show here that different strains of Botrytis cinerea and Sclerotinia sclerotiorum have opposite sensitivities to RLs and FGs on plate experiments. Overall, B. cinerea is more sensitive to FGs while S. sclerotiorum is more sensitive to RLs. Electron microscopy observations demonstrated that RLs induce mycelial destructuring by asperities emergence and hyphal fusions whereas FGs promote swelling and formation of vesicle-like structures due to vacuole fusions and autophagy. Permeability studies, phosphatidylserine externalization and reactive oxygen species production assessments showed a programmed cell death triggering by RLs at medium concentrations (until 50 μg mL
-1 ) and necrosis characteristics at higher concentration. Programmed cell death was always observed on hyphae treated with FGs. Quantifications of mycelial ergosterol content indicated that a higher ergosterol rate in S. sclerotiorum correlates with increasing sensitivity to RLs. Oppositely, a lower ergosterol rate in B. cinerea correlates with increasing sensitivity to FGs, which was confirmed by ergosterol biosynthesis inhibition with tebuconazole. This gain of knowledge will help to better understand the mode of action of RLs and FGs to fight specific plant fungal diseases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Botcazon, Bergia, Lecouturier, Dupuis, Rochex, Acket, Nicot, Leclère, Sarazin and Rippa.)- Published
- 2022
- Full Text
- View/download PDF
290. Bio-emulsifying and biodegradation activities of syringafactin producing Pseudomonas spp. strains isolated from oil contaminated soils.
- Author
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Zouari O, Lecouturier D, Rochex A, Chataigne G, Dhulster P, Jacques P, and Ghribi D
- Subjects
- Biodegradation, Environmental, Hydrocarbons, Soil, Surface-Active Agents, Petroleum, Pseudomonas
- Abstract
Pseudomonas strains isolated from oil contaminated soils were screened for biosurfactant production. Three out of eleven Pseudomonas isolates were selected for their high emulsifying activity (E24 value on n-hexadecane ~ 78%). These isolates (E39, E311 and E313) were identified as members of the P. putida group using phenotypical methods and a molecular approach. To identify the chemical nature of produced biosurfactants, thin layer chromatography and MALDI-ToF mass spectrometry analysis were carried out and revealed lipopeptides belonging to the syringafactin family. The activity of the produced biosurfactants was stable over a pH range of 6-12, at high salinity (10%) and after heating at 80 °C. Tests in contaminated sand micro-bioreactors showed that the three strains were able to degrade diesel. These results suggest the potential of these syringafactin producing strains for application in hydrocarbon bioremediation.
- Published
- 2019
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291. The Tunisian oasis ecosystem is a source of antagonistic Bacillus spp. producing diverse antifungal lipopeptides.
- Author
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El Arbi A, Rochex A, Chataigné G, Béchet M, Lecouturier D, Arnauld S, Gharsallah N, and Jacques P
- Subjects
- Antifungal Agents chemistry, Bacillus genetics, Bacillus isolation & purification, Ecosystem, Fungi drug effects, Fungi growth & development, Fusarium drug effects, Lipopeptides chemistry, Lipopeptides pharmacology, Phoeniceae microbiology, Plant Diseases prevention & control, Rhizosphere, Tunisia, Antibiosis, Antifungal Agents isolation & purification, Antifungal Agents metabolism, Bacillus metabolism, Lipopeptides isolation & purification, Lipopeptides metabolism, Soil Microbiology
- Abstract
The use of microbial products has become a promising alternative approach to controlling plant diseases caused by phytopathogenic fungi. Bacteria isolated from the date palm tree rhizosphere of the Tunisian oasis ecosystem could provide new biocontrol microorganisms adapted to extreme conditions, such as drought, salinity and high temperature. The aim of this study was to screen bacteria isolated from the rhizosphere of the date palm tree for their ability to inhibit phytopathogenic fungi, and to identify molecules responsible for their antifungal activity. Screening for antifungal activity was performed on twenty-eight isolates. Five antagonistic isolates were selected and identified as different species of Bacillus using phenotypical methods and a molecular approach. The five antagonistic Bacillus isolated showed tolerance to abiotic stresses (high temperature, salinity, drought). Their ability to produce lipopeptides was investigated using a combination of two techniques: PCR amplification and MALDI-ToF mass spectrometry. Analyses revealed that the antagonistic isolates produced a high diversity of lipopeptides that belonged to surfactin, fengycin, iturin and kurstakin families. Their antagonistic activity, related to their capacity for producing diverse antifungal lipopeptides and their tolerance to abiotic stresses, highlighted Bacillus strains isolated from the rhizosphere of the date palm tree as potential biocontrol agents for combatting plant diseases in extreme environments., (Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)
- Published
- 2016
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292. Unkempt is negatively regulated by mTOR and uncouples neuronal differentiation from growth control.
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Avet-Rochex A, Carvajal N, Christoforou CP, Yeung K, Maierbrugger KT, Hobbs C, Lalli G, Cagin U, Plachot C, McNeill H, and Bateman JM
- Subjects
- Animals, Brain metabolism, Cell Line, Cell Proliferation, Drosophila Proteins metabolism, Mutation, Photoreceptor Cells cytology, Photoreceptor Cells metabolism, Protein Binding, RNA Interference, Retina metabolism, Signal Transduction, Cell Differentiation genetics, DNA-Binding Proteins genetics, Drosophila genetics, Drosophila metabolism, Drosophila Proteins genetics, Gene Expression Regulation, Neurons cytology, Neurons metabolism, TOR Serine-Threonine Kinases metabolism
- Abstract
Neuronal differentiation is exquisitely controlled both spatially and temporally during nervous system development. Defects in the spatiotemporal control of neurogenesis cause incorrect formation of neural networks and lead to neurological disorders such as epilepsy and autism. The mTOR kinase integrates signals from mitogens, nutrients and energy levels to regulate growth, autophagy and metabolism. We previously identified the insulin receptor (InR)/mTOR pathway as a critical regulator of the timing of neuronal differentiation in the Drosophila melanogaster eye. Subsequently, this pathway has been shown to play a conserved role in regulating neurogenesis in vertebrates. However, the factors that mediate the neurogenic role of this pathway are completely unknown. To identify downstream effectors of the InR/mTOR pathway we screened transcriptional targets of mTOR for neuronal differentiation phenotypes in photoreceptor neurons. We identified the conserved gene unkempt (unk), which encodes a zinc finger/RING domain containing protein, as a negative regulator of the timing of photoreceptor differentiation. Loss of unk phenocopies InR/mTOR pathway activation and unk acts downstream of this pathway to regulate neurogenesis. In contrast to InR/mTOR signalling, unk does not regulate growth. unk therefore uncouples the role of the InR/mTOR pathway in neurogenesis from its role in growth control. We also identified the gene headcase (hdc) as a second downstream regulator of the InR/mTOR pathway controlling the timing of neurogenesis. Unk forms a complex with Hdc, and Hdc expression is regulated by unk and InR/mTOR signalling. Co-overexpression of unk and hdc completely suppresses the precocious neuronal differentiation phenotype caused by loss of Tsc1. Thus, Unk and Hdc are the first neurogenic components of the InR/mTOR pathway to be identified. Finally, we show that Unkempt-like is expressed in the developing mouse retina and in neural stem/progenitor cells, suggesting that the role of Unk in neurogenesis may be conserved in mammals.
- Published
- 2014
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293. Influence of abrasion on biofilm detachment: evidence for stratification of the biofilm.
- Author
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Rochex A, Massé A, Escudié R, Godon JJ, and Bernet N
- Subjects
- Bacteria genetics, Bioreactors, Biotechnology, DNA, Bacterial analysis, Ecosystem, Equipment Design, Microspheres, Polymerase Chain Reaction, Polymorphism, Single-Stranded Conformational, Polypropylenes, Bacteria growth & development, Bacterial Adhesion, Biofilms growth & development, Stress, Mechanical
- Abstract
The objective of this paper was to understand the detachment of multispecies biofilm caused by abrasion. By submitting a biofilm to different abrasion strengths (collision of particles), stratification of biofilm cohesion could be highlighted and related to stratification of biofilm bacterial communities using the PCR-SSCP fingerprint method. The biofilm comprised a thick top layer, weakly cohesive and composed of one dominant species, and a thin basal layer, strongly cohesive and composed of a more diverse population. These observations suggest that microbial composition of biofilms may be an important parameter in understanding biofilm detachment.
- Published
- 2009
- Full Text
- View/download PDF
294. Role of shear stress on composition, diversity and dynamics of biofilm bacterial communities.
- Author
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Rochex A, Godon JJ, Bernet N, and Escudié R
- Subjects
- DNA Primers, DNA, Bacterial isolation & purification, Equipment Design, Escherichia coli genetics, Escherichia coli isolation & purification, Genetic Variation, Polymerase Chain Reaction, Polymorphism, Single-Stranded Conformational, Bacteria growth & development, Biofilms growth & development, Bioreactors microbiology, Stress, Mechanical
- Abstract
This article evaluates the effect of shear stress on the composition of biofilm bacterial communities. For the first time, a Conical Couette-Taylor Reactor (CCTR) was used to develop biofilms at varying shear stresses (from 0.055 to 0.27 Pa) and provided a useful model for studying the effect of hydrodynamics on biofilms. The composition, diversity and dynamics of biofilm bacterial communities were analysed using the PCR-SSCP fingerprint method. Results clearly demonstrate a link between shear stress and composition of the microbial communities. High shear stresses decrease biofilm diversity and the analysis of biofilm community dynamics suggests that shear stress would slow down biofilm maturation and tend to maintain a young biofilm.
- Published
- 2008
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295. The mineralization of 5-amino-2,4,6-triiodoisophthalic acid by a two-stage fixed-bed reactor.
- Author
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Lecouturier D, Rochex A, and Lebeault JM
- Subjects
- Aerobiosis, Anaerobiosis, Biodegradation, Environmental, Bioreactors, Diatrizoate chemistry, Hydrogen-Ion Concentration, Iohexol analogs & derivatives, Iohexol chemistry, Time Factors, Triiodobenzoic Acids chemistry, Biomass, Triiodobenzoic Acids metabolism
- Abstract
Iodinated X-ray contrast media have been detected in hospital effluent, sewage treatment plant effluent, rivers and groundwater aquifers. No process has been developed to remove triiodinated aromatic molecules. In this paper, we present a biological sequential process using an anaerobic fixed-bed reactor coupled in series with an aerobic fixed-bed reactor for degrading 5-amino-2,4,6-triiodoisophthalic acid (ATIA), the core structure of a X-ray contrast media family. The results obtained showed that the coupled reactor eliminated up to 870+/-44 mg of carbon L(-1) day(-1), with a molar ethanol/ATIA ratio of 4 in the feeding medium. The anaerobic reactor (ANR) undertook the majority of the deiodination of the aromatic nucleus and had a maximum deiodination rate of 23.4+/-0.06 mM day(-1). The aerobic reactor (AER) mineralized ATIA and was also able to eliminate its metabolites. This study suggests that the mineralization of ATIA can be achieved efficiently in a coupled anaerobic-aerobic bioreactor.
- Published
- 2008
- Full Text
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296. Rac2 is a major actor of Drosophila resistance to Pseudomonas aeruginosa acting in phagocytic cells.
- Author
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Avet-Rochex A, Perrin J, Bergeret E, and Fauvarque MO
- Subjects
- Animals, Antimicrobial Cationic Peptides chemistry, Drosophila melanogaster metabolism, Gram-Negative Bacteria metabolism, Macrophages metabolism, Mitogen-Activated Protein Kinase 8 metabolism, Models, Biological, Phagocytosis, Plasma Cells metabolism, Plasma Cells microbiology, Sepsis, cdc42 GTP-Binding Protein metabolism, RAC2 GTP-Binding Protein, ADP Ribose Transferases metabolism, Bacterial Toxins metabolism, Drosophila melanogaster microbiology, Pseudomonas aeruginosa metabolism, rac GTP-Binding Proteins metabolism
- Abstract
Pathogen recognition and engulfment by phagocytic cells of the blood cell lineage constitute the first line of defense against invading pathogens. This cellular immune response is conserved throughout evolution and depends strictly on cytoskeletal changes regulated by the RhoGTPases family. Many pathogens have developed toxins modifying RhoGTPases activity to their own benefit. In particular, the Exoenzyme S (ExoS) toxin of the Gram-negative bacteria Pseudomonas aeruginosa is directly injected into the host cell cytoplasm and contains a GAP domain (ExoSGAP) targeting RhoGTPases. Searching for the contribution of each RhoGTPases, Rho1, Rac1, Rac2, Mtl (Mig2-like) and Cdc42 to fly resistance to P. aeruginosa infections, we found that Rac2 is required to resist to P. aeruginosa and to other Gram-negative or Gram-positive bacteria. The Rac2 immune-deficient phenotype is attributable to defective engulfment of pathogens since Rac2-mutant macrophages exhibited strong reduction in the phagocytosis level of both Gram-negative and Gram-positive bacterial particles whereas systemic immune signaling pathways, including Toll, Immune deficiency and Jun kinases, were not affected. Co-expression of Rac2 and ExoSGAP rescued the increased sensitivity to P. aeruginosa observed in ExoSGAP-expressing flies suggesting that Rac2 is the main host factor whose function is inhibited by the GAP domain of the ExoS toxin.
- Published
- 2007
- Full Text
- View/download PDF
297. Effects of nutrients on biofilm formation and detachment of a Pseudomonas putida strain isolated from a paper machine.
- Author
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Rochex A and Lebeault JM
- Subjects
- Carbon metabolism, Glucose pharmacology, Nitrogen metabolism, Pseudomonas putida drug effects, Time Factors, Biofilms growth & development, Paper, Pseudomonas putida physiology
- Abstract
The aim of this study was to determine the effect of varying nutrient conditions on biofilm formation of a Pseudomonas putida strain isolated from a paper machine under controlled conditions. Biofilm accumulation, was investigated using a laminar flow cell reactor in a defined mineral medium. Our results indicate that increasing nutrient concentration (from 0.1 to 0.5 gl(-1) glucose, C/N=40, C/P=100) or phosphate concentration (from C/P=200 to C/P=100) increased the rate and extent of biofilm accumulation, however, higher nutrient (1 gl(-1) glucose, C/N=40, C/P=100) or phosphate (C/P=50) concentration reduced biofilm accumulation rate because of a higher detachment. The rate and extent of biofilm accumulation increased with nitrogen concentration (from C/N=90 to C/N=20). Detachment is a key parameter that influences biofilm accumulation since the early stage (2h) of colonisation and strongly depends on nutrient conditions. In practice, controlling nutrient levels may be interesting to reduce biofilm formation in the paper industry.
- Published
- 2007
- Full Text
- View/download PDF
298. An on-line technique for monitoring propionic acid fermentation.
- Author
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Benjelloun H, Rochex A, Lecouturier D, Dechemi S, and Lebeault JM
- Subjects
- Acetates metabolism, Bioreactors, Fermentation, Hydrogen-Ion Concentration, Lactic Acid metabolism, Manometry methods, Oxygen analysis, Oxygen metabolism, Pressure, Propionibacterium growth & development, Propionibacterium metabolism, Carbon Dioxide metabolism, Industrial Microbiology methods, Online Systems, Propionates metabolism
- Abstract
An on-line technique, based on measuring the increase in pressure due to CO(2) release in a closed air-tight reactor, was used to evaluate the fermentation of lactate by propionibacteria. The method was applied to batch cultures of Propionibacterium shermanii grown in yeast extract/sodium lactate medium containing lactate as a carbon source under micro-aerophilic conditions. Gas pressure evolution was compared both with substrate consumption and metabolites production and with acidification and growth. Linear relationships were found between gas pressure variation, lactate consumption and propionate and acetate production. The technique also enabled the evaluation of total CO(2) produced, by taking account of pressure, oxygen and pH measurements. These results tend to show that this simple and rapid method could be useful to monitor propionic acid bacteria growth.
- Published
- 2005
- Full Text
- View/download PDF
299. Adhesion of a Pseudomonas putida strain isolated from a paper machine to cellulose fibres.
- Author
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Rochex A, Lecouturier D, Pezron I, and Lebeault JM
- Subjects
- Culture Media chemistry, Environmental Microbiology, Hydrophobic and Hydrophilic Interactions, Kinetics, Osmolar Concentration, Pseudomonas putida isolation & purification, Solvents chemistry, Static Electricity, Temperature, Time Factors, Bacterial Adhesion, Cellulose, Pseudomonas putida physiology
- Abstract
The adhesion to cellulose fibres of a strain of Pseudomonas putida isolated from a paper machine was studied under different environmental conditions. The physicochemical properties of both P. putida cells and cellulose fibres were also determined to better understand the adhesion phenomenon. Adhesion was rapid (1 min) and increased with time, cell concentration and temperature (from 25 to 40 degrees C), indicating that bacterial adhesion to cellulose fibres is essentially governed by a physicochemical process. The P. putida cell surface was negatively charged, as shown by electrophoretic mobility measurements, and was hydrophilic due to a strong electron-donor character, as shown by the microbial adhesion to solvents method. Cellulose fibres were shown to be hydrophilic by contact angle measurements using the capillary rise method. These results suggest the importance of Lewis acid-base interactions in the adhesion process. In various ionic solutions (NaCl, KCl, CaCl(2) and MgCl(2)), adhesion increased with increasing ionic strength up to 10-100 mM, indicating that, at low ionic strength, electrostatic interactions were involved in the adhesion process. An increase in the C/N ratio of the growth medium (from 5 to 90) decreased adhesion but this could not be related to changes in physicochemical properties, suggesting that other factors may be involved. In practice, temperature, ionic strength and nitrogen concentration must be taken into consideration to reduce bacterial contamination in the paper industry.
- Published
- 2004
- Full Text
- View/download PDF
300. Enrichment and properties of an anaerobic mixed culture that reductively deiodinates 5-amino-2,4,6-triiodoisophthalic acid, an X-ray contrast agent precursor.
- Author
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Lecouturier D, Rochex A, and Lebeault JM
- Subjects
- Acetates metabolism, Anaerobiosis, Biodegradation, Environmental, Butyrates metabolism, Culture Media, Ethanol metabolism, Iodides analysis, Lactic Acid metabolism, Nitrates metabolism, Phthalic Acids analysis, Sulfates metabolism, Sulfites metabolism, Thiosulfates metabolism, Water Pollution, Chemical, Contrast Media metabolism, Phthalic Acids metabolism, Sewage microbiology, Triiodobenzoic Acids metabolism
- Abstract
5-Amino-2,4,6-triiodoisophthalic acid (ATIA), both a precursor and a degradative intermediate of triiodinated contrast media, was anaerobically converted by sludge from a wastewater treatment plant. ATIA conversion took place only when an electron donor such as ethanol was added. A stable mixed culture was established by transfer to a defined synthetic mineral medium with ATIA and ethanol. It could be maintained for 1 year when the sulfate concentration was kept below 30 microM. Transient appearance of 5-amino-2,4-diiodoisophthalic acid, iodide release (2.7 mol iodide/mol ATIA) and accumulation of 5-aminoisophthalic acid indicated that ATIA was reductively dehalogenated. The enriched mixed culture also dehalogenated ATIA derivatives but deiodination remained incomplete. ATIA was the sole terminal electron acceptor used by the mixed culture during deiodination. The ratio of electrons transferred to ATIA, 0.83, was consistent with a respiratory metabolism. Formate, acetate, lactate, butyrate and hydrogen were also used as electron donors. Deiodination was inhibited by a headspace of air or by addition of nitrate, sulfite or thiosulfate. The reaction was 2.6 times slower with sulfate than without.
- Published
- 2003
- Full Text
- View/download PDF
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