Broomrape weeds. Underground mechanisms of parasitism and associated strategies for their control: a review

SPE & AgrosupPôle GESTADBroomrapes are plant-parasitic weeds which constitute one of the most difficult-to-control of all biotic constraints that affect crops in Mediterranean, central and eastern Europe, and Asia. Due to their physical and metabolic overlap with the crop, their underground parasitism, their achlorophyllous nature, and hardly destructible seed bank, broomrape weeds are usually not controlled by management strategies designed for non-parasitic weeds. Instead, broomrape are in a current state of intensification and spread due to lack of broomrape-specific control programs, unconscious introduction to new areas and may be decline of herbicide use and global warming to a lesser degree. We reviewed relevant facts about the biology and physiology of broomrape weeds and the major feasible control strategies. The points of vulnerability of some underground events, key for their parasitism such as crop-induced germination or haustorial development are reviewed as inhibition targets of the broomrape-crop association. Among the reviewed strategies are those aimed 1) to reduce broomrape seed bank viability, such as fumigation, herbigation, solarization and use of broomrape-specific pathogens; 2) diversion strategies to reduce the broomrape ability to timely detect the host such as those based on promotion of suicidal germination, on introduction of allelochemical interference, or on down-regulating host exudation of germination-inducing factors; 3) strategies to inhibit the capacity of the broomrape seedling to penetrate the crop and connect with the vascular system, such as biotic or abiotic inhibition of broomrape radicle growth, crop resistance to broomrape penetration either natural, genetically engineered or elicited by biotic- or abiotic-resistance-inducing agents and 4) strategies acting once broomrape seedling has bridged its vascular system with that of the host, aimed to impede or to endure the parasitic sink such as those based on the delivery of herbicides via haustoria, use of resistant and tolerant varieties or implementation of cultural practices improving crop competitivenes

A new Strategy to Improve Drug Delivery to the Maxillary Sinuses: The Frequency Sweep Acoustic Airflow

International audiencePurpose Enhancement of intra-nasal sinus drug deposition involves nebulization of a drug superimposed by the acoustic airflow characterized by a specific frequency. We investigated the impact of fixed frequency versus frequency sweep acoustic airflow on the improvement of aerosolized drug penetration into the maxillary sinuses.Methods Fixed frequency and frequency sweep acoustic airflow were generated using a prototype of variable frequency nebulizing system, and their effect on the intra-nasal sinus aerosol deposition in a ‘nasal replica’, a transparent, water-resistant, non-porous resin replica of the human plastinated cast created using a stereolithography technique, was tested. Sodium fluoride and gentamicin were chosen as markers. In addition to this, the effect of sweep cycle and intensity variation was also studied. Results Studies performed using fixed frequency acoustic airflow showed that each of the maxillary sinuses of the ‘nasal replica’ required specific frequency for the optimal intra-nasal sinus aerosol deposition; depending on the ostia of the left and right maxillary sinuses which are different. Intra-nasal sinus drug deposition experiments under the effect of the frequency sweep acoustic airflow showed an optimal aerosol deposition into both maxillary sinus of the ‘nasal replica’. Studies on the effect of the duration of the sweep cycle showed that the shorter the cycle the better the deposition.Conclusion Our study demonstrates the benefit of frequency sweep acoustic airflow on the drug deposition into maxillary sinuses of the ‘nasal replica’ characterized by ostia of different geometry. However, the delivery rates of the ‘nasal replica’ cannot be directly applied to real human chronic rhinosinusitis condition; further in vivo studies have to be conducted

Synthèse d'a-C-galactosylcéramides difluorés et évaluation de leurs propriétés immunorégulatrices pour le traitement des maladies autoimmunes systémiques

Les O-glycoconjugués et les dérivés glycosidiques sont des composés naturels impliqués dans de nombreux processus biologiques. Cependant, leurs propriétés sont grévées par la médiocre stabilité in vivo de la liaison osidique. Il est donc intéressant de développer des mimes non hydrolysables. Nous nous sommes intéressés au remplacement de l'oxygène anomérique par un groupement gem-difluorométhylène.La synthèse d'analogues difluorés d'a-galactosylcéramides avec diverses longueurs de chaînes grasses est décrite dans ce travail. La partie C-glycosidique de ces molécules est construite par l'application d'une séquence d'addition radicalaire et de réduction diastérosélective. La chaîne phytosphingosine est introduite par le synthon a-CF -galactose via un transfert de l'O-2 au carbone pseudo-anomérique, puis un couplage peptidique permet de former la partie céramide. Quatre analogues possédant diverses chaînes phytosphingosines (C H , C H ) et divers acides gras (C H , C H et C H ) ont été synthétisés et évalués biologiquement.O-glycoconjugates and carbohydrate-based molecules are natural compounds implied in many biological processes. However, their properties are burdened by the low in vivo stability of the osidic bond. It is thus interesting to develop non hydrolizable mimetics. We were interested in the replacement of the anomeric oxygen by a gem-difluoromethylene group.The synthesis of difluorinated a-galactosylceramides featuring various lipidic chain lenghts is described herein. The C-glycosidic part of these molecules is construted by a sequence of radical addition and diastereoselective reduction. The phytosphingosine chain is introduced on this intermediate by an O-2 to C-1' migration and the ceramide synthesis is completed by a petidic coupling. Four analogues featuring various phytosphingosines chains (C H , C H ) and fatty acids (C H , C H et C H ) were synthetized and biologically assessed.ROUEN-INSA Madrillet (765752301) / SudocSudocFranceF

Intraoperative MRI for the microsurgical resection of meningiomas close to eloquent areas or dural sinuses: patient series

BACKGROUND: Meningiomas are the most commonly encountered nonglial primary intracranial tumors. The authors report on the usefulness of intraoperative magnetic resonance imaging (iMRI) during microsurgical resection of meningiomas located close to eloquent areas or dural sinuses and on the feasibility of further radiation therapy. OBSERVATIONS: Six patients benefited from this approach. The mean follow-up period after surgery was 3.3 (median 3.2, range 2.1–4.6) years. Five patients had no postoperative neurological deficit, of whom two with preoperative motor deficit completely recovered. One patient with preoperative left inferior limb deficit partially recovered. The mean interval between surgery and radiation therapy was 15.8 (median 16.9, range 1.4–40.5) months. Additional radiation therapy was required in five cases after surgery. The mean preoperative tumor volume was 38.7 (median 27.5, range 8.6–75.6) mL. The mean postoperative tumor volume was 1.2 (median 0.8, range 0–4.3) mL. At the last follow-up, all tumors were controlled. LESSONS: The use of iMRI was particularly helpful to (1) decide on additional tumor resection according to iMRI findings during the surgical procedure; (2) evaluate the residual tumor volume at the end of the surgery; and (3) judge the need for further radiation and, in particular, the feasibility of single-fraction radiosurgery

Loss of AMP-activated protein kinase alpha 2 subunit in mouse beta-cells impairs glucose-stimulated insulin secretion and inhibits their sensitivity to hypoglycaemia

AMPK (AMP-activated protein kinase) signalling plays a key role in whole-body energy homoeostasis, although its precise role in pancreatic β-cell function remains unclear. In the present stusy, we therefore investigated whether AMPK plays a critical function in β-cell glucose sensing and is required for the maintenance of normal glucose homoeostasis. Mice lacking AMPKα2 in β-cells and a population of hypothalamic neurons (RIPCreα2KO mice) and RIPCreα2KO mice lacking AMPKα1 (α1KORIPCreα2KO) globally were assessed for whole-body glucose homoeostasis and insulin secretion. Isolated pancreatic islets from these mice were assessed for glucose-stimulated insulin secretion and gene expression changes. Cultured β-cells were examined electrophysiologically for their electrical responsiveness to hypoglycaemia. RIPCreα2KO mice exhibited glucose intolerance and impaired GSIS (glucose-stimulated insulin secretion) and this was exacerbated in α1KORIPCreα2KO mice. Reduced glucose concentrations failed to completely suppress insulin secretion in islets from RIPCreα2KO and α1KORIPCreα2KO mice, and conversely GSIS was impaired. β-Cells lacking AMPKα2 or expressing a kinase-dead AMPKα2 failed to hyperpolarize in response to low glucose, although KATP (ATP-sensitive potassium) channel function was intact. We could detect no alteration of GLUT2 (glucose transporter 2), glucose uptake or glucokinase that could explain this glucose insensitivity. UCP2 (uncoupling protein 2) expression was reduced in RIPCreα2KO islets and the UCP2 inhibitor genipin suppressed low-glucose-mediated wild-type mouse β-cell hyperpolarization, mimicking the effect of AMPKα2 loss. These results show that AMPKα2 activity is necessary to maintain normal pancreatic β-cell glucose sensing, possibly by maintaining high β-cell levels of UCP2