Antifungal effects of iron sulfate on grapevine fungal pathogens

International audienceThe present study aimed to determine the most efficient experimental conditions of iron sulfate use leading to optimal inhibition in the development of fungal pathogens. Assays have been focused on fungal species inducing severe grapevine diseases. FeSO4 directly inhibited the in vitro mycelial growth of Botrytis cinerea, Eutypa lata, Phaeomoniella chlamydospora, Phaeoacremonium aleophilum, Diplodia seriata, and Neofusicoccum parvum with variable efficiency in the range of 0.5-10 mM. The development was always completely inhibited at 20 mM. This inhibitory effect was greatly increased at acidic pH values. The anionic moiety of the molecule was of importance since bromide, chloride and sulfate were highly active, whereas acetate and oxalate showed a small effect. Electron microscope observations on E. lata and B. cinerea showed that a treatment with FeSO4 induced dramatic changes in the hyphal organization leading to cell death. No toxicity was observed on grapevine leaves following repeated FeSO4 sprays in the antifungal concentration range. Therefore, FeSO4 may be proposed to effectively replace the long-term pollutant use of CuSO4 as an antifungal agent, with the additional advantage of iron being an important plant micronutrient

Les myélinosomes : une nouvelle voie du contrôle de qualité des protéines

International audienceMaintenance of cell proteostasis relies on two degradation pathways: proteasome and autophagy. Here we describe a new proteostasis pathway avoiding degradation of abnormal proteins yet carrying them outside the cell using nanovesicles called myelinosomes. These myelinosomes are produced in pathological or stress situations in relation with genetic or environmental factors. Myelinosome vesicles are nano-sized multi-stacked membrane structures, resembling myelin sheath. It has recently been shown in two models of genetic diseases (Huntington's disease and cystic fibrosis) that myelinosomes are important for eliminating mutant proteins in an unusual secretory process, thus preventing their accumulation and aggregation in cells

NaCl – Changes stem morphology, anatomy and phloem structure in Lucerne ( Medicago sativa cv. Gabès): Comparison of upper and lower internodes

International audienceIn M. sativa cv. Gabès plants treated with 150mM NaCl, the height of the stem is decreased and the internode number, length and diameter are reduced. This depressive effect on growth, but also on photosynthetic activity and water balance, is accompanied by structural changes. In the upper internodes, NaCl treatment increases cambium development, so that the vascular ring is initiated earlier than in controls. In the lower internodes, the number of lignified phloem fibers is increased by NaCl, and their wall thickness is augmented, compared to controls; in the phloem complex, the nacreous layer is enlarged, the number of internal wall ingrowths is increased, but companion cells are damaged. In the treated lower internodes, few vessels occur in the secondary xylem, which is by contrast rich in lignified fibers and in wide vessels grouped in the metaxylem area; protoxylem parenchyma and adjacent pith are also lignified. In addition, in treated lower internodes, starch grains are less abundant than in controls, and this variation might be related to the decrease of photosynthesis. When taken together, qualitative and quantitative results indicate that the saline stress has a marked morpho-anatomical impact on the M. sativa Gabès stem. In particular, variations of secondary derivative distribution, increased wall thickening, lignification of phloem and xylem fibers and damage in the phloem complex are NaCl-induced responses, and are more expressed in the lower than in the upper internodes. The reinforcement of the stem lignified vasculature is thus a positive response to stress, but it has a negative impact on the quality of the forage

NaCl effect on the distribution of wall ingrowth polymers and arabinogalactan proteins in type A transfer cells of Medicago sativa Gabès leaves

International audienceWe studied the distribution of wall ingrowth (WI) polymers by probing thin sections of companion cells specialized as transfer cells in minor veins of Medicago sativa cv Gabès blade with affinity probes and antibodies specific to polysaccharides and glycoproteins. The wall polymers in the controls were similar in WIs and in the primary wall but differently distributed. The extent of labeling in these papillate WIs differed for JIM5 and JIM7 homogalacturonans but was in the same range for LM5 and LM6 rhamnogalacturonans and xyloglucans. These data show that WI enhancement probably requires arabinogalactan proteins (JIM8) mainly localized on the outer part of the primary wall and WIs. By comparison, NaCl-treated plants exhibited cell wall polysaccharide modifications indicating (1) an increase in unesterified homogalacturonans (JIM5), probably implicated in Na+ binding and/or polysaccharide network interaction for limiting turgor variations in mesophyll cells; (2) enhancement of the xyloglucan network with an accumulation of fucosylated xyloglucans (CCRC-M1) known to increase the capacity of cellulose binding; and (3) specific recognition of JIM8 arabinogalactan proteins that could participate in both wall enlargement and cohesion by increasing the number of molecular interactions with the other polymers. In conclusion, the cell wall polysaccharide distribution in enlarged WIs might (1) participate in wall resistance to sequestration of Na+, allowing a better control of hydric homeostasis in mesophyll cells to maintain metabolic activity in source leaves, and (2) maintain tolerance of M. sativa to NaCl

Left posterolateral strangulated congenital diaphragmatic hernia in children: About a case at the Charles de Gaulle Paediatric Teaching Hospital in Ouagadougou (Burkina Faso)

Late presentation of congenital diaphragmatic hernia is uncommon. It poses considerable diagnostic challenges when it strangulates. The authors report a case of a left posterolateral strangulated congenital diaphragmatic hernia in a 5-year-old child diagnosed at the stage of acute intestinal occlusion with intestinal necrosis and managed successfully. A strangulated congenital diaphragmatic hernia should be suspected in the case of an association of sudden-onset respiratory and digestive manifestations with no sign of trauma or specific pulmonary history. It then requires an antero posterior thoracic X-ray or, even better, a thoracic-abdominal scan to confirm the diagnosis

Better Outcomes with Intranigral versus Intrastriatal Cell Transplantation: Relevance for Parkinson’s Disease

International audienceIntrastriatal embryonic ventral mesencephalon grafts have been shown to integrate, survive,and reinnervate the host striatum in clinical settings and in animal models of Parkinson’s disease.However, this ectopic location does not restore the physiological loops of the nigrostriatal pathwayand promotes only moderate behavioral benefits. Here, we performed a direct comparison of thepotential benefits of intranigral versus intrastriatal grafts in animal models of Parkinson’s disease.We report that intranigral grafts promoted better survival of dopaminergic neurons and that onlyintranigral grafts induced recovery of fine motor skills and normalized cortico-striatal responses.The increase in the number of toxic activated glial cells in host tissue surrounding the intrastriatalgraft, as well as within the graft, may be one of the causes of the increased cell death observed in theintrastriatal graft. Homotopic localization of the graft and the subsequent physiological cell rewiringof the basal ganglia may be a key factor in successful and beneficial cell transplantation procedures

Morphological properties of vermiculite particles in size-selected fractions obtained by sonication

International audienceThe objective of this study is to determine the morphological properties of vermiculite particles obtained by sonication followed by separation into different size fractions (0.1-0.2, 1-2 and 10-20 mu m). These size fractions were chosen because they represent the wide range of particle sizes encountered in natural media. As previously reported, the crystal-chemistry of this vermiculite from Santa Olalla (Huelva, Spain) was found to be unaffected by the sonication process, although a loss of crystallinity and an increase in structural disorder might have occurred for the finest fraction. Using low-pressure argon adsorption analyses and a suite of microscopy techniques (i.e., atomic force, optical and transmission electron microscopy), the geometrical properties of the particles, including the distribution of the basal and lateral surfaces and aspect ratios, were obtained. Good agreement was observed between the gas adsorption experiments when applying the derivative isotherm summation procedure and the atomic force or optical microscopy analyses. However, the surface area was overestimated by transmission electron microscopy, which was attributed to the sample preparation technique. All of these data demonstrated that the particle aspect ratios are similar for all fractions, and the finest particles tend to show slightly more elongated surface morphologies than the coarser particles. Finally, a comparison of the distribution of lateral, basal and interlayer adsorption sites to the experimental cation-exchange capacity (CEC) showed that only the basal and interlayer sites are available in the conditions of CEC analysis. Based on these findings, the pertinence of using these size fractions as models to better understand the interactions between swelling clay minerals and water/solutes is discussed