Pourquoi inciter les agriculteurs à innover dans les techniques de désherbage ? Etat de la pratique et propositions de la recherche

International audienceL'abondance et la diversité des adventices constituent des contraintes majeures de la production des systèmes de culture des savanes d'Afrique Centrale. Dans les systèmes traditionnels, le sarclage manuel sélectif, apparaît comme une technique à fonctions multiples. Dans les systèmes plus "modernes", les techniques de désherbage chimique et mécanique sont de plus en plus souvent associées. On constate des décalages importants entre les prescriptions techniques et les pratiques. Des sarclages tardifs combinés à une maîtrise approximative des herbicides contraignent souvent l'agriculteur à l'abandon d'une partie des parcelles et engendrent des pertes de production significatives (20% pour le cotonnier). Depuis une dizaine d'années, on constate une poussée de l'innovation dans la lutte contre les adventices. Au Nord-Cameroun, le désherbage chimique réalise une percée vigoureuse sur coton et maïs avec des herbicides totaux et de pré-levée, et plus récemment sur le muskuwaari. Aussi depuis 4 ans, les ventes de sarcleurs et de butteurs prennent le pas sur les ventes de charrues témoignant de l'intérêt croissant des agriculteurs pour les techniques de désherbage. Ces constats ont conduit diverses équipes de recherche à analyser les changements et à proposer des nouveaux concepts de désherbage. Pour la mécanisation, la recherche propose des attelages plus maniables (monobovin), des bâtis monovalents économiques et préconise une intervention précoce. Concernant le désherbage chimique plusieurs pistes sont explorées soit en complément de la mécanisation dans un esprit de lutte intégrée, soit en substitution tout en évitant la sélection d'espèces envahissantes. (Résumé d'auteur

Selective inhibition of eukaryotic translation initiation factor 2 alpha dephosphorylation potentiates fatty acid-induced endoplasmic reticulum stress and causes pancreatic beta-cell dysfunction and apoptosis.

Free fatty acids cause pancreatic beta-cell apoptosis and may contribute to beta-cell loss in type 2 diabetes via the induction of endoplasmic reticulum stress. Reductions in eukaryotic translation initiation factor (eIF) 2alpha phosphorylation trigger beta-cell failure and diabetes. Salubrinal selectively inhibits eIF2alpha dephosphorylation, protects other cells against endoplasmic reticulum stress-mediated apoptosis, and has been proposed as a beta-cell protector. Unexpectedly, salubrinal induced apoptosis in primary beta-cells, and it potentiated the deleterious effects of oleate and palmitate. Salubrinal induced a marked eIF2alpha phosphorylation and potentiated the inhibitory effects of free fatty acids on protein synthesis and insulin release. The synergistic activation of the PERK-eIF2alpha branch of the endoplasmic reticulum stress response, but not of the IRE1 and activating transcription factor-6 pathways, led to a marked induction of activating transcription factor-4 and the pro-apoptotic transcription factor CHOP. Our findings demonstrate that excessive eIF2alpha phosphorylation is poorly tolerated by beta-cells and exacerbates free fatty acid-induced apoptosis. This modifies the present paradigm regarding the beneficial role of eIF2alpha phosphorylation in beta-cells and must be taken into consideration when designing therapies to protect beta-cells in type 2 diabetes.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

La France savante

En France, le CTHS est depuis 1834 expert dans la détermination de ce qui est ou non « savant », c’est-à-dire, dans l’esprit de François Guizot, ici présenté par Simone Mazauric, ce qui doit être fondé en raison et conduit par des méthodes indiscutables. Pourtant, on n’a pas attendu 1834 pour mettre sur le devant de la scène des « savants » reconnus comme tels de leur temps et se regroupant pour mieux appréhender des questions complexes. Si l’érudit peut être solitaire, le « savant » ne l’est jamais, car porté par un groupe d’amis, de collègues, de correspondants…, il répond à une requête sociale et travaille en réseau. Guizot a voulu s’appuyer sur les sociétés locales plutôt que sur les universités comme en Allemagne ; ce choix est révélateur d’une volonté de porter l’esprit scientifique partout dans les élites provinciales en s’appuyant sur des associations volontaires en plein essor au moment où il est au pouvoir. Pour Guizot en effet, il n’y a pas de savants sans réseaux scientifiques, sans groupes permanents ou non qui portent des questions et travaillent en émulation. Même si l’on sait que les Grecs les premiers ont su grouper les compétences, il n’est pas évident de décrypter qui appartient au cercle, au groupe d’amis, qui participe à la conversation et à l’élaboration en commun des solutions. Les historiens peuvent suivre ces réseaux dès lors qu’ils ont une documentation qui leur permet d’en cerner l’existence et d’en distinguer les participants : correspondances, échanges de manuscrits puis éditions, voire procès… Bien entendu, tout devient plus simple avec la multiplication de la documentation, c’est pourquoi la base de données collaborative du CTHS commence au XVIe siècle. Mais qu’est-ce qu’une science, qu’est-ce qu’un « savant », quels sont ses objets ? C’est cette interrogation qu’explorent tous les auteurs de ce volume

Considerations and consequences of allowing DNA sequence data as types of fungal taxa

Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.Peer reviewe

Health-Related Quality of Life in Chronic HCV-Infected Patients Switching to Pegylated-Interferon-Free Regimens (ANRS CO20 CUPIC Cohort Study and SIRIUS Trial)

International audienceObjective We aimed to compare health-related quality of life (HRQL) during and after HCV treatment in patients receiving pegylated-interferon (PEG-IFN)-containing therapy (including boceprevir or telaprevir - ANRS CO20 CUPIC cohort) who subsequently switched to PEG-IFN-free regimens (sofosbuvir + ledipasvir with or without ribavirin (RBV) - SIRIUS trial).Methods Two analyses were performed. The first compared physical (PCS) and mental (MCS) HRQL (MOS SF-12) scores during treatment between CUPIC and SIRIUS. The second compared PCS and MCS scores after treatment end between CUPIC and SIRIUS. The analyses used linear regression mixed models adjusted for pre-treatment HRQL scores, gender and age at each visit.Results Among patients enrolled successively in both studies, 43 (corresponding to 212 HRQL assessments) and 43 (82 HRQL assessments) were eligible for the “during” and “post" treatment analyses, respectively. In the “during-treatment” analysis, we found both significantly higher PCS and MCS values during PEG-IFN-free treatment than for PEG-IFN-containing treatment. In the “post-treatment” analysis, results showed significantly higher MCS values after PEG-IFN-free treatment than after PEG-IFN-containing treatment. No significant difference was found for PCS in “post-treatment analysis”.Conclusions These results highlight an improvement in both physical and mental HRQL during HCV treatment, but no major improvement in physical HRQL after treatment end, when comparing PEG-IFN-free regimens with PEG-IFN-containing regimens. This suggests that in the PEG-IFN-free regimens era, screening and comprehensive care of comorbidities and residual somatic symptoms during treatment, and especially after HCV clearance, are still needed to improve patient outcomes

Health-Related Quality of Life in Chronic HCV-Infected Patients Switching to Pegylated-Interferon-Free Regimens (ANRS CO20 CUPIC Cohort Study and SIRIUS Trial)

International audienceObjective We aimed to compare health-related quality of life (HRQL) during and after HCV treatment in patients receiving pegylated-interferon (PEG-IFN)-containing therapy (including boceprevir or telaprevir - ANRS CO20 CUPIC cohort) who subsequently switched to PEG-IFN-free regimens (sofosbuvir + ledipasvir with or without ribavirin (RBV) - SIRIUS trial).Methods Two analyses were performed. The first compared physical (PCS) and mental (MCS) HRQL (MOS SF-12) scores during treatment between CUPIC and SIRIUS. The second compared PCS and MCS scores after treatment end between CUPIC and SIRIUS. The analyses used linear regression mixed models adjusted for pre-treatment HRQL scores, gender and age at each visit.Results Among patients enrolled successively in both studies, 43 (corresponding to 212 HRQL assessments) and 43 (82 HRQL assessments) were eligible for the “during” and “post" treatment analyses, respectively. In the “during-treatment” analysis, we found both significantly higher PCS and MCS values during PEG-IFN-free treatment than for PEG-IFN-containing treatment. In the “post-treatment” analysis, results showed significantly higher MCS values after PEG-IFN-free treatment than after PEG-IFN-containing treatment. No significant difference was found for PCS in “post-treatment analysis”.Conclusions These results highlight an improvement in both physical and mental HRQL during HCV treatment, but no major improvement in physical HRQL after treatment end, when comparing PEG-IFN-free regimens with PEG-IFN-containing regimens. This suggests that in the PEG-IFN-free regimens era, screening and comprehensive care of comorbidities and residual somatic symptoms during treatment, and especially after HCV clearance, are still needed to improve patient outcomes