Pathogenesis-related proteins in grapevines induced by salicylic acid and Botrytis cinerea

The grapevine pathogenesis-related proteins (PRs) were studied in order to determine the spatial localization and the temporal production of these inducible proteins. We used leaves of plants obtained from woody cuttings grown in greenhouse. Elicitations were done either with salicylic acid or with strains of Botrytis cinerea. Several PRs extractable at pH 2.8 were found to accumulate in grapevine leaves after salicylic acid treatment or Botrytis infection (SDS-PAGE, coomassie blue). Elicitation with salicylic acid has induced one new protein at about 32 kDa. Botrytis infection has resulted in the accumulation of four major acid-soluble proteins with apparent molecular weights of 27, 32, 34 and 38 kDa. Immunodetections using antisera raised against the tobacco PR-2 family have shown several bands, particularly two bands at 34 and 36 kDa revealed by the anti-2a and present both with salicylic acid and Botrytis

Association entre les variants rares du gène Abraxas et la susceptibilité au cancer du sein : une étude cas-témoins

Ce mémoire est le fruit d’un travail de deux ans dans le laboratoire de Génomique des Cancer du Dr Simard. La première partie du mémoire est une mise en contexte sur le cancer du sein et sur les deux principales voies de réparation des cassures doubles brins de l’ADN, puis se poursuit par la problématique ayant menée à l’élaboration de mon projet. Cette partie s’achève par le descriptif des techniques de laboratoire et des outils d’analyse utilisés pour ce projet. En deuxième partie se trouve l’article scientifique rédigé à partir des résultats obtenus pendant mes recherches, avant de se terminer par une conclusion

Metabolic profiling of Lolium perenne shows functional integration of metabolic responses to diverse subtoxic conditions of chemical stress

International audiencePlant communities are confronted with a great variety of environmental chemical stresses. Characterization of chemical stress in higher plants has often been focused on single or closely related stressors under acute exposure, or restricted to a selective number of molecular targets. In order to understand plant functioning under chemical stress conditions close to environmental pollution conditions, the C3 grass Lolium perenne was subjected to a panel of different chemical stressors (pesticide, pesticide degradation compound, polycyclic aromatic hydrocarbon, and heavy metal) under conditions of seed-level or root-level subtoxic exposure. Physiological and metabolic profiling analysis on roots and shoots revealed that all of these subtoxic chemical stresses resulted in discrete physiological perturbations and complex metabolic shifts. These metabolic shifts involved stressor-specific effects, indicating multilevel mechanisms of action, such as the effects of glyphosate and its degradation product aminomethylphosphonic acid on quinate levels. They also involved major generic effects that linked all of the subtoxic chemical stresses with major modifications of nitrogen metabolism, especially affecting asparagine, and of photorespiration, especially affecting alanine and glycerate. Stress-related physiological effects and metabolic adjustments were shown to be integrated through a complex network of metabolic correlations converging on Asn, Leu, Ser, and glucose-6-phosphate, which could potentially be modulated by differential dynamics and interconversion of soluble sugars (sucrose, trehalose, fructose, and glucose). Underlying metabolic, regulatory, and signalling mechanisms linking these subtoxic chemical stresses with a generic impact on nitrogen metabolism and photorespiration are discussed in relation to carbohydrate and low-energy sensing

Moderate conformational impact of citrate on ovotransferrin considerably increases its capacity to self-assemble at the interface

International audienceWe have compared the behavior of ovotransferrin at the air-solution interface in the presence of a monovalention (acetate), or a divalent ion (citrate), the latter being known to induce conformational changesof this protein upon interaction with its iron-binding sites. We have characterised the adsorption layer atthe air–water interface in terms of homogeneity, surface concentration excess and rheological propertiesat pH 4.0. Besides we have investigated the bulk conformation in the presence of the two anions. In thepresence of citrate only, interfacial layers display well-defined domains of higher overall surface concentrationsuggesting multilayers adsorption. Citrate also induces higher helical content and stabilizes theprotein against thermal denaturation. Hence we propose that these changes are involved in the propensityof ovotransferrin to self-assemble at the air–water interface resulting in thick and heterogeneousinterfacial layer

Increased mortality in hematological malignancy patients with acute respiratory failure from undetermined etiology : a Groupe de Recherche en Réanimation Respiratoire en Onco-Hématologique (Grrr-OH) study

Background: Acute respiratory failure (ARF) is the most frequent complication in patients with hematological malignancies and is associated with high morbidity and mortality. ARF etiologies are numerous, and despite extensive diagnostic workflow, some patients remain with undetermined ARF etiology. Methods: This is a post-hoc study of a prospective multicenter cohort performed on 1011 critically ill hematological patients. Relationship between ARF etiology and hospital mortality was assessed using a multivariable regression model adjusting for confounders. Results: This study included 604 patients with ARF. All patients underwent noninvasive diagnostic tests, and a bronchoscopy and bronchoalveolar lavage (BAL) was performed in 155 (25.6%). Definite diagnoses were classified into four exclusive etiological categories: pneumonia (44.4%), non-infectious diagnoses (32.6%), opportunistic infection (10.1%) and undetermined (12.9%), with corresponding hospital mortality rates of 40, 35, 55 and 59%, respectively. Overall hospital mortality was 42%. By multivariable analysis, factors associated with hospital mortality were invasive pulmonary aspergillosis (OR 7.57 (95% CI 3.06-21.62); p 7 (OR 3.32 (95% CI 2.15-5.15); p < 0.005) and an undetermined ARF etiology (OR 2.92 (95% CI 1.71-5.07); p < 0.005). Conclusions: In patients with hematological malignancies and ARF, up to 13% remain with undetermined ARF etiology despite comprehensive diagnostic workup. Undetermined ARF etiology is independently associated with hospital mortality. Studies to guide second-line diagnostic strategies are warranted

Native spider silk as a biological optical fiber.

International audienceIn this study, we demonstrate the use of eco-friendly native spider silk as an efficient optical fiber in air, highly bent fibers, and physiological liquid. We also integrated the silk filament in a photonic chip made of polymer microstructures fabricated by UV lithography. The molding process is non-destructive for silk and leads to an efficient micro-optical coupling between silk and synthetic optical structures. These optical performances combined with the unique biocompatibility, bioresorbability, flexibility, and tensile strength of silk filaments pave the way for new applications in biological media and for original biophotonic purposes

Impact of a nurses' protocol-directed weaning procedure on outcomes in patients undergoing mechanical ventilation for longer than 48 hours: a prospective cohort study with a matched historical control group

INTRODUCTION: The aim of the study was to determine whether the use of a nurses' protocol-directed weaning procedure, based on the French intensive care society (SRLF) consensus recommendations, was associated with reductions in the duration of mechanical ventilation and intensive care unit (ICU) length of stay in patients requiring more than 48 hours of mechanical ventilation. METHODS: This prospective study was conducted in a university hospital ICU from January 2002 through to February 2003. A total of 104 patients who had been ventilated for more than 48 hours and were weaned from mechanical ventilation using a nurses' protocol-directed procedure (cases) were compared with a 1:1 matched historical control group who underwent conventional physician-directed weaning (between 1999 and 2001). Duration of ventilation and length of ICU stay, rate of unsuccessful extubation and rate of ventilator-associated pneumonia were compared between cases and controls. RESULTS: The duration of mechanical ventilation (16.6 ± 13 days versus 22.5 ± 21 days; P = 0.02) and ICU length of stay (21.6 ± 14.3 days versus 27.6 ± 21.7 days; P = 0.02) were lower among patients who underwent the nurses' protocol-directed weaning than among control individuals. Ventilator-associated pneumonia, ventilator discontinuation failure rates and ICU mortality were similar between the two groups. DISCUSSION: Application of the nurses' protocol-directed weaning procedure described here is safe and promotes significant outcome benefits in patients who require more than 48 hours of mechanical ventilation