Cathepsin B pH-Dependent Activity Is Involved in Lysosomal Dysregulation in Atrophic Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is characterized by retinal pigment epithelial (RPE) cell dysfunction beginning at early stages of the disease. The lack of an appropriate in vitro model is a major limitation in understanding the mechanisms leading to the occurrence of AMD. This study compared human-induced pluripotent stem cell- (hiPSC-) RPE cells derived from atrophic AMD patients () to hiPSC-RPE cells derived from healthy elderly individuals with no drusen or pigmentary alteration (). Control and AMD hiPSC-RPE cell lines were characterized by immunofluorescence, flow cytometry, and electronic microscopy. The toxicity level of iron after Fe-NTA treatment was evaluated by an MTT test and by the detection of dichloro-dihydro-fluorescein diacetate. Twelve hiPSC-RPE cell lines (6 AMD and 6 controls) were used for the experiment. Under basal conditions, all hiPSC-RPE cells expressed a phenotypic profile of senescent cells with rounded mitochondria at passage 2. However, the treatment with Fe-NTA induced higher reactive oxygen species production and cell death in hiPSC-RPE AMD cells than in hiPSC-RPE Control cells. Interestingly, functional analysis showed differences in lysosomal activity between the two populations. Indeed, Cathepsin B activity was higher in hiPSC-RPE AMD cells compared to hiPSC-RPE Control cells in basal condition and link to a pH more acidic in this cell population. Moreover, oxidative stress exposure leads to an increase of Cathepsin D immature form levels in both populations, but in a higher proportion in hiPSC-RPE AMD cells. These findings could demonstrate that hiPSC-RPE AMD cells have a typical disease phenotype compared to hiPSC-RPE Control cells

Characterization Methods for Components and Materials

International audienceThis chapter gives a general view of various spectroscopic and electron microscopic techniques that are common and increasingly used for the physiochemical characterization of fuel cell materials. The measuring principle of the X-ray photoelectron spectroscopy (XPS), the scanning electron microscopy (SEM), the transmission electron microscopy (TEM), the atomic force microscopy (AFM), the infrared (IR) spectroscopy, and the Raman spectroscopy method are simplified and described by a selected example for each characterization method. The gained insights from the structure, morphology, and surface analyses of individual fuel cell components (e.g., membrane, catalyst, support material, etc.) are used for performance improvement to drastically enhance the power of the respective fuel cell system

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

Appendicular bilharzioma: An unusual cause of acute intestinal obstruction in childhood (a case report at Charles de Gaulle Paediatric Teaching Hospital of Ouagadougou)

The authors report the case of a 12-year-old boy admitted to the surgical emergency department of Charles de Gaulle Paediatric Teaching Hospital of Ouagadougou for acute abdominal pain. A strangulation of the terminal ileum by a tumour-like appendix wound around the bowel loop was seen during operation. The histological examination of the removed appendix disclosed eggs of Schistosoma haematobium and concluded to bilharzian appendicitis. A course of praziquantel treatment was instituted, and the patient underwent an event-free recovery. Such cases report are infrequent, even in areas where bilharzia-related diseases are endemic. It is important to recognise them and to treat them in an aetiological manner so as to prevent any potential complications. The diagnosis is always an operatory and histological curiosity. Appendectomy and treatment with a course of praziquantel seem quite suitable for this situation

Biocompatible Spherical Gold Nanoparticles Synthesis in Aqueous Tetraethylene Oxide Solution and Their Cellular Uptake

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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