26 research outputs found
Permissiveness of human biliary epithelial cells to infection by hepatitis C virus.
No full textThe cellular tropism of hepatitis C virus (HCV) is an important but much debated issue. Permissivity to HCV of biliary cells has never been demonstrated. In this context, we used gallbladder epithelial cells (GBEC) as a model of the more proximal biliary epithelium. These cells were isolated from HCV-positive and -negative individuals and cultured for up to 40 days. Biliary cells from HCV-negative subjects were infected in vitro with various inocula. The retention of GBEC functional characteristics was assessed by the expression of cystic fibrosis transmembrane conductance regulator (CFTR). All 12 GBEC tested from HCV-negative patients were successfully infected by HCV. This was assessed by: 1) the detection of HCV-RNA positive and negative strands; 2) the detection of the viral capsid by immunofluorescence; and 3) the combination of single-strand conformation polymorphism (SSCP) and HVR1 sequence analysis demonstrating the distinct majoritary HCV genomes in serum and in GBEC. The level of HCV RNA in cell extracts and supernatants was low, but HCV infection was highly reproducible. Our results expand those showing the cellular tropism of HCV, and demonstrate the sensitivity of biliary cells to HCV infection. This might have an important impact in terms of pathogenesis and pathological features of HCV infection. In addition, given the easy access to these cells and the high reproducibility of in vitro infection, they should constitute an important tool for studies aimed at analyzing the issue of HCV penetration and neutralizing antibodies
Mergey, Eugene (Death, 1887-10-25)
No full textAge at death: 11 yrsPg 159/1887/359/FW M/City/Dr. Rendigs Cor/Osseforth/St.John'sOriginal record filed in drawer labeled 'MER-METZE'
Bilan sur le sepsis sévère et le choc septique
No full textLe choc septique se défini par une réponse inflammatoire liée à une infection, compliquée d'une hypotension persistante malgré un remplissage vasculaire ou nécessitant l'administration de catécholamine. La prise en charge du traitement comprend deux aspects : le traitement étiologique et le traitement symptomatique. Le choc septique présente un taux de mortalité entre 40 et 60%, constituant la première cause de décès en unité de soins intensifs. Les germes responsables du chos septique sont en constante évolution. L'épidémiologie très diverse conduit à des sémiologie polymorphes en fonction des susceptibilités cliniques et génétiques de chacun. Les recherches de traitements du choc septique ont abouti à de nombreux échecs. Ceux-ci sont partiellement expliqués par les imprécisions des définitions utilisées et la remise en cause des méthodes d'études. Le seul médicaments innovant du choc septique est la drotrégogine alpha activée, commercialisée sous le nom de XIGRIS. Adjuvant du traitement conventionnel, elle pallie le déficit en protéine C activée lors du choc septique, réduisant de 19,4% le taux de mortalité. La perspective d'avenir du traitement du choc septique est représentée par la puce à ADN, technologie permettant de connaître les susceptibilités de chaque patient afin d'adapter le traitement.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF
Regulation of secretion in cultured tracheal serous cells by protein kinases A and C
No full text We recently reported that cultured gland serous cells release chondroitin sulfate proteoglycans (CSPGs) in response to beta-adrenergic agonists. In this study, we analyzed this regulatory pathway and other cellular mechanisms responsible for CSPG secretion. We show the following. 1) Isoproterenol increased CSPG secretion in a concentration-dependent manner, with maximal stimulation (50%) obtained at 10(-5) M; at this concentration, the beta-agonist also stimulated protein kinase A (PKA) by 50%, whereas it increased cellular adenosine 3',5'-cyclic monophosphate (cAMP) content by 300%. 2) Phenylephrine (10(-5) M), 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (1.6 x 10(-7) M), and A23187 (10(-6) M) also stimulated CSPG secretion; this stimulation was concomitant with protein kinase C (PKC) translocation from cytosol to membrane, was blocked by sphingosine (2 x 10(-5) M), and was additive with that elicited by isoproterenol. 3) All PKC activators potentiated the isoproterenol-induced increased in cAMP accumulation without modifying the activation of PKA elicited by the beta-agonist. Our results indicate that although the signaling pathways triggered by alpha- and beta-adrenergic agonists converge at the level of adenylate cyclase in tracheal serous cells, PKA and PKC independently regulate CSPG secretion. </jats:p
Choix de chroniques et mémoires sur l'histoire de France : avec notices biographiques / par J.-A.-C. Buchon.
No full textCollection : Panthéon littéraire. Littérature française. HistoireCollection : Panthéon littéraireComprend : Mémoires de Michel de Castelnau ; Le siège de Metz par l'empereur Charles V, en l'an 1552... ; Discours de Gaspar de Colligny, seigneur de Chastillon, admiral de France, où sont sommairement contenues les choses qui se sont passées durant le siège de Sainct-Quentin, en 1557 ; Mémoire du voyage de M. le duc de Guyse en Italie, son retour, la prinse de Callais et de Thionville en 1557 et 1558 ; Mémoires de messire Guillaume de Rochechouart ; Mémoires d'Achille Gamon, avocat et consul d'Annonai, 1552-1586 ; Mémoires de Jean Philippi ; Mémoires de Henry de La Tour d'Auvergne, vicomte de Turenne, et depuis duc de Bouillon, adressés à son fils le prince de Sedan ; Mémoires des choses advenues en France ès guerres civiles, depuis l'an 1560 jusques en l'an 1596 ; Mémoires de Marguerite de Valois, reine de France et de Navarre ; Mémoires de Jacques-Auguste de Thou, depuis 1553 jusqu'en 1601 ; Mémoires de Jean Choisnin ; Mémoires du sieur Jean de Mergey, gentilhomme champenois ; Mémoires de Mathieu Merle, Baron de SalavasContient une table des matièresAvec mode text
Characterization of PGPR for improving plant resistance under environmental stresses
No full textRhizobacteria having plant growth promoting (PGPR) characteristics amplify plant resistance to biotic and abiotic stresses. Relatively recently, it was discovered that many PGPR containing the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase protect plants against environmental stresses such as flooding, metals, organic toxicants, high salt, drought and phytopathogens.
Arsenic pollution has become a severe worldwide problem due the toxicity of its inorganic forms, arsenate and arsenite. Arsenate is the main species of arsenic in aerated soils and can induce toxic effects in plants. Its uptake and toxicity are intimately linked to the phosphorus-status of plants due to the chemical and biochemical analogies of arsenate and phosphate.
Bacteria use general and specific detoxification strategies to withstand the growth restriction when they are exposed to arsenic. While the general systems alleviate arsenic induced cell toxicities, the specific systems are involved in arsenic transformation, sequestration and solubilization.
A group of arsenic resistant rhizobacteria were isolated and identified from uncontaminated and arsenic contaminated sites. Twelve aerobic rhizobacteria showed a diverse arsenate and arsenite resistance level when growing on rich or defined media supplemented with up to 400 mmol/l of arsenate and 25 mmol/l of arsenite. General resistance mechanisms were investigated by studying microbial growth in LB medium under osmotic stress induced by sodium chloride, sodium arsenate, and polyethylene glycol (PEG 6000). The growth characteristics of the most arsenic resistant bacteria were compared in the presence of 200 mmol/l of sodium arsenate or 1200 mmol/l of sodium chloride (with similar ionic strength) and under an osmotic stress (-1.5 M Pa) generated by 175 mmol/l of sodium arsenate, 400 mmol/l of NaCl and 26% PEG 6000 (Sosa et al., 2005). Results showed that growth was generally better under osmotic stress generated by arsenic than under that generated by NaCl or PEG 6000. Among the isolates, all exhibiting some potential plant growth promotion characteristics, eight strains were ACC deaminase positive and three solubilized phosphate. Arsenic specific resistant mechanisms were determined by identifying the functional genes involved in arsenate reduction (ars and arr genes) based on PCR method. Arsenic transformations by rhizobacteria were analyzed in Tris Mineral Medium with low phosphate content (Mergey et al., 1985) supplemented with gluconate (0.6% , w/v) (TMMG) and spiked with 3mM of arsenate or arsenite.
Experimental results suggested that these arsenic resistant rhizobacteria are metabolically adapted to arsenic-induced osmotic stress in addition to the specific system to control the uptake, reduction and extrusion of arsenic. These isolates can potentially be used to remove arsenic from soils and also to increase the phosphorus bioavailability in agricultural soils as well as in arsenic- contaminated soils to improve plants’ phosphorus nutritio
Effect of environmental stresses on plant grow promoting characteristics of the arsenite oxidizer Pseudomonas sp. strain N2
No full textHeavy metals resistant bacteria with plant growth-promoting (PGP) characteristics can be used to facilitate the proliferation of plants under environmentally stressful conditions, such as drought, salinity and heavy metals contamination. Moreover, arsenic-transforming PGP bacteria, influencing arsenic mobilization in soil, can enhance arsenic uptake by plant.
The aims of this study were: (i) to characterize an arsenic-resistant Pseudomonas sp. strain N2 for resistance to osmotic stresses, production of stress-related phytohormones, PGP traits and arsenic transformation, and (ii) to evaluate the effect of arsenic on these characteristics.The capability to respond to osmotic stresses (-1.5 MPa) was evaluated by measuring the bacterial growth in LB medium separately added of: 175 mmol/L of Na3AsO4, 400 mmol/L of NaCl, or 26% (w/v) PEG6000 (Sosa et al., 2005). Production of stress-related phytohormones (indole acetic acid IAA, and jasmonic acid, JA) was determined in yeast mannitol medium (YEM) in the absence and in the presence of arsenate (50 mmol/L), arsenite (3 mmol/L), and PEG6000 (13.7% w/v), as stress agents. Tested PGP characteristics were: the ability to grow on 1-aminocyclopropane-1-carboxylic acid (ACC) as sole nitrogen source, the production of siderophores and proteolitic, chitinase and phosphate solubilising activities. Phosphate solubilisation activity was evaluated in YEM with Ca3(PO4)2 (5 g/L) in the absence or in the presence of arsenite or arsenate. Arsenic transforming capabilities were evaluated during 72 h growth in Tris Mineral Medium (Mergey et al., 1985) supplemented with 0.6% (w/v) gluconate (TMMG) spiked with 3 mmol/L of arsenite or arsenate.
Strain N2 was able to tolerate -1.5 MPa: osmotic stress generated by the presence of arsenic was tolerated better than those generated by NaCl and PEG6000. The strain was able to produce 68 pmol/ml of IAA and 0.18 pmol/ml of JA and to solubilise 100 mg/L phosphate. While the production of IAA was enhanced by the presence of arsenic forms it was not affected by osmotic stress. On the contrary, phosphate solubilization was impaired by arsenic. Strain N2 possessed all the tested PGP characteristics and it completely oxidized arsenite to arsenate, while it did not reduce arsenate.
Our results suggest that strain N2 possesses PGP characteristics not affected by the presence of arsenic and of osmotic stresses. Moreover, the ability to solubilize phosphate may contribute to improve plants’ phosphorous nutrition. Pseudomonas sp. strain N2 might be a candidate inoculum useful to amplify plant resistance in stress conditions.
Acknowledgments
Funding for this work was provided by: Fondazione CARIPLO (project 2010-2221) and PRIN (project 2010JBNLJ7_004)
EBP50, a scaffold protein participating in the proliferation of cholangiocytes, is delocalized in the ductular reaction associated with cystic fibrosis liver disease
No full textLinking habitat characteristics with genetic diversity of the European pine marten (Martes martes) in France
No full textInternational audienc
CFTR gene transfer corrects defective glycoconjugate secretion in human CF epithelial tracheal cells
No full text We demonstrate that in immortalized normal human tracheal epithelial cells (NT-1 and 56FHTE8o-) 14C-labeled glycoconjugate secretion may be regulated independently by agonists of the protein kinase A (PKA) and protein kinase C (PKC) signaling pathways. In contrast, in immortalized cystic fibrosis (CF) human tracheal epithelial cells (CFT-1 and CFT-2), regulation is defective for agonists specific for the PKA but not for the PKC pathway. To characterize the involvement of the cystic fibrosis transmembrane conductance regulator (CFTR) in regulated glycoconjugate secretion, we examined the effect of adenovirus-mediated gene transfer of CFTR to CF and control cells. Forty-eight hours after infection, at a multiplicity of infection of 50 plaque-forming units per cell, high levels of CFTR mRNA were detected by reverse transcription-polymerase chain reaction, and de novo synthesis of CFTR protein was demonstrated by immunoblotting. Gene transfer to CF cells restored defective adenosine 3',5'-cyclic monophosphate (cAMP)-dependent secretion not only of chloride but also of glycoconjugates. Taken together, these results argue for a role for CFTR in cAMP-mediated glycoconjugate secretion. </jats:p
