Chitin perception in plasmodesmata characterizes submembrane immune-signaling specificity in plants

The plasma membrane (PM) is composed of heterogeneous subdomains, characterized by differences in protein and lipid composition. PM receptors can be dynamically sorted into membrane domains to underpin signaling in response to extracellular stimuli. In plants, the plasmodesmal PM is a discrete microdomain that hosts specific receptors and responses. We exploited the independence of this PM domain to investigate how membrane domains can independently integrate a signal that triggers responses across the cell. Focusing on chitin signaling, we found that responses in the plasmodesmal PM require the LysM receptor kinases LYK4 and LYK5 in addition to LYM2. Chitin induces dynamic changes in the localization, association, or mobility of these receptors, but only LYM2 and LYK4 are detected in the plasmodesmal PM. We further uncovered that chitin-induced production of reactive oxygen species and callose depends on specific signaling events that lead to plasmodesmata closure. Our results demonstrate that distinct membrane domains can integrate a common signal with specific machinery that initiates discrete signaling cascades to produce a localized response

A calmodulin-like protein regulates plasmodesmal closure during bacterial immune responses

Plants sense microbial signatures via activation of pattern recognition receptors (PPRs), which trigger a range of cellular defences. One response is the closure of plasmodesmata, which reduces symplastic connectivity and the capacity for direct molecular exchange between host cells. Plasmodesmal flux is regulated by a variety of environmental cues but the downstream signalling pathways are poorly defined, especially the way in which calcium regulates plasmodesmal closure. Here, we identify that closure of plasmodesmata in response to bacterial flagellin, but not fungal chitin, is mediated by a plasmodesmal-localized Ca2+ -binding protein Calmodulin-like 41 (CML41). CML41 is transcriptionally upregulated by flg22 and facilitates rapid callose deposition at plasmodesmata following flg22 treatment. CML41 acts independently of other defence responses triggered by flg22 perception and reduces bacterial infection. We propose that CML41 enables Ca2+ -signalling specificity during bacterial pathogen attack and is required for a complete defence response against Pseudomonas syringae.Bo Xu, Cecilia Cheval, Anuphon Laohavisit, Bradleigh Hocking, David Chiasson, Tjelvar S. G. Olsson, Ken Shirasu, Christine Faulkner and Matthew Gilliha

Relationship between blood lactate and early hepatic dysfunction in acute circulatory failure.

PURPOSE: The purpose of this study was to assess the influence of early hepatic dysfunction on lactate level in patients with acute circulatory failure in a retrospective study. MATERIALS AND METHODS: Blood lactate was compared between patients in acute circulatory failure (systolic blood pressure 60 micromol/L or SGOT > 100 IU/L during the first 48 hours). Univariate and multivariate analysis were performed to assess the effects of early hepatic dysfunction and other clinical and biological data on serum lactate levels in patients with acute circulatory failure. RESULTS: The study included 92 patients, mean age 64+/-15 years, mean simplified acute physiology score (SAPS) 18.4+/-4.1. Early hepatic dysfunction was identified in 29 patients (32%). Mean initial blood lactate was 5.54+/-4.78 mmol/L. Overall intensive care unit mortality was 67.3%. Although patients with and without hepatic dysfunction showed no significant difference in terms of mean SAPS, mean lowest systolic blood pressure, and mortality, serum lactate was higher in the group with hepatic dysfunction than in the group without hepatic dysfunction (8.24+/-6.49 mmol/L v4.29+/-3.09 mmol/L, P < .001). Factors independently associated with serum lactate were the existence of early hepatic dysfunction (P < .01), a nondistributive type of shock (P < .05), and the mean initial amount of epinephrine (P < .05). CONCLUSIONS: This study suggests that early hepatic dysfunction plays an important role in serum lactate elevation in acute circulatory failure

La filière équine française à l’horizon 2030 : premières réflexions prospectives

National audienceAlors que monter à cheval n’est plus une nécessité, l’équitation de loisir connait un engouement croissant et le secteur des courses bénéficie d’un fort intérêt de la population pour les paris hippiques. Dans ce contexte dynamique, l’ouverture des paris en ligne, le relèvement de la TVA, la diminution des subventions de l’Etat, mais aussi le développement de la concurrence internationale sur les marchés du cheval de sport font peser des incertitudes sur l’avenir et sur la poursuite des tendances actuelles. Afin d’aider les professionnels de la filière à se préparer aux évolutions futures, mais aussi pour améliorer l’offre de services, de connaissances et d’innovations dans un contexte de restructuration des services publics, l’Institut national de la recherche agronomique (INRA) et l’Institut français du cheval et de l’équitation (IFCE) ont décidé de mener une étude prospective de l’ensemble de la filière équine. Ce travail a pour objectif la définition de scenarios d’évolution possible de la filière équine française à l’horizon 2030 grâce à une démarche participative et exploratoire qui a démarré fin 2010. Les réflexions sur les tendances, ruptures ou évolutions alternatives constituent les bases de construction d’hypothèses d’évolutions contrastées, puis de scénarios, qui seront finalisés et ouverts au débat en octobre 2012

La filière équine française à l’horizon 2030 : premières réflexions prospectives

National audienceAlors que monter à cheval n’est plus une nécessité, l’équitation de loisir connait un engouement croissant et le secteur des courses bénéficie d’un fort intérêt de la population pour les paris hippiques. Dans ce contexte dynamique, l’ouverture des paris en ligne, le relèvement de la TVA, la diminution des subventions de l’Etat, mais aussi le développement de la concurrence internationale sur les marchés du cheval de sport font peser des incertitudes sur l’avenir et sur la poursuite des tendances actuelles. Afin d’aider les professionnels de la filière à se préparer aux évolutions futures, mais aussi pour améliorer l’offre de services, de connaissances et d’innovations dans un contexte de restructuration des services publics, l’Institut national de la recherche agronomique (INRA) et l’Institut français du cheval et de l’équitation (IFCE) ont décidé de mener une étude prospective de l’ensemble de la filière équine. Ce travail a pour objectif la définition de scenarios d’évolution possible de la filière équine française à l’horizon 2030 grâce à une démarche participative et exploratoire qui a démarré fin 2010. Les réflexions sur les tendances, ruptures ou évolutions alternatives constituent les bases de construction d’hypothèses d’évolutions contrastées, puis de scénarios, qui seront finalisés et ouverts au débat en octobre 2012

ANP-stimulated Na+ secretion in the collecting duct prevents Na+ retention in the renal adaptation to acid load.

We have recently reported that type A intercalated cells of the collecting duct secrete Na+ by a mechanism coupling the basolateral type 1 Na+-K+-2Cl- cotransporter with apical type 2 H+-K+-ATPase (HKA2) functioning under its Na+/K+ exchange mode. The first aim of the present study was to evaluate whether this secretory pathway is a target of atrial natriuretic peptide (ANP). Despite hyperaldosteronemia, metabolic acidosis is not associated with Na+ retention. The second aim of the present study was to evaluate whether ANP-induced stimulation of Na+ secretion by type A intercalated cells might account for mineralocorticoid escape during metabolic acidosis. In Xenopus oocytes expressing HKA2, cGMP, the second messenger of ANP, increased the membrane expression, activity, and Na+-transporting rate of HKA2. Feeding mice with a NH4Cl-enriched diet increased urinary excretion of aldosterone and induced a transient Na+ retention that reversed within 3 days. At that time, expression of ANP mRNA in the collecting duct and urinary excretion of cGMP were increased. Reversion of Na+ retention was prevented by treatment with an inhibitor of ANP receptors and was absent in HKA2-null mice. In conclusion, paracrine stimulation of HKA2 by ANP is responsible for the escape of the Na+-retaining effect of aldosterone during metabolic acidosis

Use of tunneled femoral catheters to prevent catheter-related infection. A randomized, controlled trial.

BACKGROUND: The risk for catheter-related infection seems higher with femoral catheters than with catheters inserted at other sites. OBJECTIVE: To evaluate the effect of catheter tunneling on femoral catheter-related infection in critically ill patients. DESIGN: Randomized, controlled trial. SETTING: Three intensive care units at academic hospitals in Paris, France. PATIENTS: 345 adult patients requiring a femoral venous catheter for more than 48 hours. INTERVENTION: Tunneled or nontunneled femoral catheters. MEASUREMENTS: Time to occurrence of systemic catheter-related sepsis, catheter-related bloodstream infection, and quantitative catheter tip culture with a cutoff of 10(3) colony-forming units/mL. RESULTS: Of 345 randomly assigned patients, 336 were evaluable. Probable systemic catheter-related sepsis occurred in 15 of 168 patients who received a nontunneled femoral catheter (controls) and in 5 of 168 patients who received a tunneled femoral catheter (estimated absolute risk reduction, 6% [95% CI, 0.9% to 11%]). Time to occurrence of catheter-related bloodstream infection was not significantly modified (relative risk, 0.28 [CI, 0.03 to 1.92]; P = 0.18); 3 events occurred in the control group and 1 event occurred in the tunneled-catheter group. After stratification by treatment center and adjustment for variables that were prognostic (use of broad-spectrum antimicrobial agents at catheter insertion) or imbalanced between both groups (mechanical ventilation at insertion), tunnelized catheterization reduced the proportion of patients who developed systemic catheter-related sepsis (relative risk, 0.25 [CI, 0.09 to 0.72]; P = 0.005) and positive quantitative culture of the catheter tip (relative risk, 0.48 [CI, 0.23 to 0.99]; P = 0.045). CONCLUSION: The incidence of femoral catheter-related infections in critically ill patients can be reduced by using subcutaneous tunneling

Ventilation non invasive. Les conseils 2015 du Groupe assistance ventilatoire (GAV) de la Société de pneumologie de langue française (SPLF)

A task force issued from the Groupe Assistance Ventilatoire (GAV) of the Société de Pneumologie de Langue Française (SPLF) was committed to develop a series of expert advice concerning various practical topics related to long-term non invasive ventilation by applying the Choosing Wisely® methodology. Three topics were selected: monitoring of noninvasive ventilation, the interpretation of data obtained from built-in devices coupled to home ventilators and the role of hybrid modes (target volume with variable pressure support. For each topic, the experts have developed practical tips based on a comprehensive analysis of recent insights and evidence from the literature and from clinical experience.SCOPUS: sh.jinfo:eu-repo/semantics/publishe