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Rôle de la dynamique de la membrane plasmique dans la mise en place des réactions de défense chez le tabac

2008

The binding of cryptogein, a plant defense elicitor secreted by an oomycete, to an unknown receptor triggers well-known biochemical events of early signal transduction at the plasma membrane of tobacco cells. One of these early events is the transient production of Reactive Oxygen Species (ROS) by an NADPH oxidase, NtrbohD. We were thus interested to analyze the dynamic of the plasma membrane during these early stages. We determined that internalization of the endocytotic marker FM4-64 is stimulated a few minutes after addition of cryptogein to tobacco BY-2 cells. This stimulation is specific to the signal transduction pathway elicited by cryptogein since a lipid transfer protein, which bin…

Tuning Azoheteroarene Photoswitch Performance through Heteroaryl Design

2017

International audience; Photoswitchable compounds, which can be reversibly switched between two isomers by light, continue to attract significant attention for a wide array of applications. Azoheteroarenes represent a relatively new but understudied type of photoswitch, where one of the aryl rings from the conventional azobenzene class has been replaced with a five-membered heteroaromatic ring. Initial studies have suggested the azoheteroarenes – the arylazopyrazoles in particular – to have excellent photoswitching properties (quantitative switching and long Z isomer half-life). Here we present a systematic computational and experimental study to elucidate the origin of the long thermal hal…

Reti comunicative ed interazioni virtuali nella soluzione di dilemmi sociali on line

2004

Impact of Novel Energy Management Actions on Household Appliances for Money Savings and CO2 Emissions Reduction

2009

In order to obtain CO2 emissions reductions, energy management control actions inside apartments and detached houses have to be carried out. In this work, new control actions devoted to the reduction of electrical energy consumptions inside typical Italian apartments are proposed. These “Distributed on Site” (DoS) actions consist in employing specific control strategies to smartly exploit the hot water provided by a solar panel, the electricity generated by a photovoltaic panel and the delayed starting of appliances.

A multifuctional nanoplatform for drug targeted delivery based on radiation-engineered nanogels

2020

Abstract Under a rational design, combining biologically active molecules, ligands to specific cell receptors and fluorescent, radioactive or paramagnetic labels into a single nano-object can bridge the unique properties of the individual components and improve conventional sensing, imaging and therapeutic efficacies. The validation of these functional nano-objects requires careful testing both in terms of physico-chemical properties and biological behaviour in vitro and in vivo, prior to translation into the clinic. Ionising radiation of aqueous polymer solutions is a viable strategy to produce multifunctional nanogels from aqueous solutions of hydrophilic polymers. By proper selection of …

Pharmacokinetics of selective serotonin reuptake inhibitors

2000

The five selective serotonin reuptake inhibitors (SSRIs), fluoxetine, fluvoxamine, paroxetine, sertraline, and citalopram, have similar antidepressant efficacy and a similar side effect profile. They differ, however, in their pharmacokinetic properties. Under steady-state concentrations, their half-lives range between 1 and 4 days for fluoxetine (7 and 15 days for norfluoxetine) and between 21 (paroxetine) and 36 (citalopram) hr for the other SSRIs. Sertraline and citalopram show linear and fluoxetine, fluvoxamine, and paroxetine nonlinear pharmacokinetics. SSRIs underlie an extensive metabolism with high interindividual variability, whereby cytochrome P450 (CYP) isoenzymes play a major rol…

Bacteria Associated with Copestylum (Diptera, Syrphidae) Larvae and Their Cactus Host Isolatocereus dumortieri

2011

We describe the gut bacterial diversity inhabiting two saprophagous syrphids and their breeding substrate (decayed tissues of the columnar cactus Isolatocereus dumortieri). We analyzed the gut microbiota of Copestylum latum (scooping larvae that feed on decayed cactus tissues) and Copestylum limbipenne (whose larvae can also feed on semiliquid tissues) using molecular techniques. DNA was extracted from larval guts and cactus tissues. The V1-V3 region of the 16S rRNA genes was amplified and sequenced. A total of 31079 sequences were obtained. The main findings are: C. limbipenne is dominated by several Enterobacteriaceae, including putative nitrogen-fixing genera and pectinolitic species and…

Excitotoxic Hippocampal Membrane Breakdown and its Inhibition by Bilobalide: Role of Chloride Fluxes

2003

We have previously shown that hypoxia and N-methyl-D-aspartate (NMDA) receptor activation induce breakdown of choline-containing phospholipids in rat hippocampus, a process which is mediated by calcium influx and phospholipase A (2) activation. Bilobalide, a constituent of Ginkgo biloba, inhibited this process in a potent manner (Weichel et al., Naunyn-Schmiedeberg's Arch. Pharmacol. 360, 609-615, 1999). In this study, we used fluorescence microscopy and radioactive flux measurements to show that bilobalide does not interfere with NMDA-induced calcium influx. Instead, bilobalide seems to inhibit NMDA-induced fluxes of chloride ions through ligand-operated chloride channels. In our experimen…

Purification and characterization of the ?-β-hydroxybutyrate dehydrogenase from dromedary liver mitochondria

2001

Abstract d -β-Hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30), a membrane enzyme, has been purified to homogeneity from dromedary ( Camelus dromedarius ) liver mitochondria. Our new purification method consisted of the solubilization of mitochondrial membranes by Triton X 100 and purification of BDH by two steps: DEAE-Sephacel and Phenyl-Sepharose. The molecular mass of the enzyme subunit size was 67 kDa. The purified enzyme is recognized by anti rat liver mitochondrial BDH antibodies. Furthermore, BDH activity was absolutely dependent upon phospholipids. BDH is also characterized by specific enzymatic parameters: an optimum pH of approximately 8 for the oxidation reaction, and approximat…

Induction of tumor-cell lysis by bi-specific antibody recognizing ganglioside GD2 and T-cell antigen CD3

1993

Human tumor cells expressing ganglioside GD2 were lysed by various effector populations targeted with an anti-CD3-anti-GD2 bi-specific antibody (BAb CD3 x GD2). This antibody-heteroconjugate was prepared by chemically cross-linking the OKT-3 monoclonal antibody (MAb) reactive with CD3 antigen on T lymphocytes with the ganglioside MAb ME 361, which binds preferentially to the tumor-associated ganglioside GD2. The specificity of target-cell lysis by the cytotoxic T cells (CTL) was mediated by the specificity of the targeting antibody: GD2-negative cells were not lysed in the presence of the CD3 x GD2 BAb. A dose-dependent response was observed in a range of 10 to 10,000 ng/ml. In contrast, 2 …