Calcium-stores mediate adaptation in axon terminals of Olfactory Receptor Neurons in Drosophila

<p>Abstract</p> <p>Background</p> <p>In vertebrates and invertebrates, sensory neurons adapt to variable ambient conditions, such as the duration or repetition of a stimulus, a physiological mechanism considered as a simple form of non-associative learning and neuronal plasticity. Although various signaling pathways, as cAMP, cGMP, and the inositol 1,4,5-triphosphate receptor (InsP₃R) play a role in adaptation, their precise mechanisms of action at the cellular level remain incompletely understood. Recently, in <it>Drosophila</it>, we reported that odor-induced Ca²⁺-response in axon terminals of olfactory receptor neurons (ORNs) is related to odor duration. In particular, a relatively long odor stimulus (such as 5 s) triggers the induction of a second component involving intracellular Ca²⁺-stores.</p> <p>Results</p> <p>We used a recently developed <it>in-vivo </it>bioluminescence imaging approach to quantify the odor-induced Ca²⁺-activity in the axon terminals of ORNs. Using either a genetic approach to target specific RNAs, or a pharmacological approach, we show that the second component, relying on the intracellular Ca²⁺-stores, is responsible for the adaptation to repetitive stimuli. In the antennal lobes (a region analogous to the vertebrate olfactory bulb) ORNs make synaptic contacts with second-order neurons, the projection neurons (PNs). These synapses are modulated by GABA, through either GABAergic local interneurons (LNs) and/or some GABAergic PNs. Application of GABAergic receptor antagonists, both GABA_Aor GABA_B, abolishes the adaptation, while RNAi targeting the GABAB_R(a metabotropic receptor) within the ORNs, blocks the Ca²⁺-store dependent component, and consequently disrupts the adaptation. These results indicate that GABA exerts a feedback control. Finally, at the behavioral level, using an olfactory test, genetically impairing the GABA_BR or its signaling pathway specifically in the ORNs disrupts olfactory adapted behavior.</p> <p>Conclusion</p> <p>Taken together, our results indicate that a relatively long lasting form of adaptation occurs within the axon terminals of the ORNs in the antennal lobes, which depends on intracellular Ca²⁺-stores, attributable to a positive feedback through the GABAergic synapses.</p

Effet des écumes de canne à sucre, de la poudre et du compost à base de Chromolaena odorata (L.) King R.M. & H.E. Rob sur la croissance de l’oseille de Guinée (Hibiscus sabdariffa L.)

Dans la sous-région et particulièrement au Gabon, la pauvreté chimique des sols affecte de façon considérable la croissance des cultures vivrières et maraîchères telle que l’oseille de Guinée (Hibiscus sabdariffa L.) qui représente pourtant une source de revenus pour les producteurs. En ce sens, cette étude a porté sur l’évaluation de l’effet des écumes de canne à sucre, du compost et de la poudre de Chromolaena odorata, sur la croissance de H. sabdariffa L. L’essai a été conduit en sacs à Franceville au Sud-Est du Gabon, selon un dispositif en blocs aléatoires comportant : 3 doses de fumures organiques (15, 20 et 25 t/ha), 4 répétitions et un témoin. Les paramètres de croissance suivis ont été le diamètre et la hauteur de tiges, la surface foliaire et les ramifications. Les données recueillies ont fait l’objet d’une analyse de la variance (ANOVA) au seuil de 5%. Pour ces paramètres étudiés, les plants de H. sabdariffa L. traités avec C3 (25 t/ha compost de C. odorata) ont présenté, par rapport au témoin, des différences respectivement de l’ordre de 67% ; 72,30% ; 85,40% et 89,85%. L’effet induit par C3 sur la croissance a été meilleur par comparaison avec les autres traitements.© 2015 International Formulae Group. All rights reserved.Mots clés: Hibiscus sabdariffa L., compost, poudre, ecumes, croissance, GabonEnglish Title:  Effect of sugarcane foam, Chromolaena odorata (L.) RM King &amp; HE Rob powder and compost on the growth of Guinea sorrel (Hibiscus sabdariffa L.)English AbstractIn the sub central african region and particularly in Gabon, poor soils dramatically affect the growth of food and vegetable crops such as Guinea sorrel (Hibiscus sabdariffa L.) which nevertheless represents a source of income for producers. In this sense, the aim of this study was to evaluate the effect of sugarcane foam, compost and C. odorata powder on the growth of H. sabdariffa L. The test was conducted in bags at Franceville in the southeast of Gabon, according to a randomized block with 3 doses of organic manure (15, 20 and 25 t/ha), 4 repetitions and a control. The growth parameters determined were diameter, stem height, leaf area and ramifications. The collected data were subject to an analysis of variance (ANOVA) at 5% level. For  the studied parameters H. sabdariffa L. plants treated with C3 (25 t/ha compost of C. odorata) showed a significant difference (p&lt;0,0001) compared to the control. The differences observed were of the order of 67%; 72.30%; 85.40% and 89.85% respectively. The induced effect by C3 treatment on growth was better compared with the other treatments.© 2015 International Formulae Group. All rights reserved.Keywords: Hibiscus sabdariffa L., compost, powder, foam, growth, Gabo

Free Fatty Acids and Fatty Acids of Triacylglycerols in Normal and Hyperkeratotic Human Stratum Corneum

The content of the free fatty acids and the fatty acids of triacylglycerols has been measured in human plantar stratum corneum from normal and hyperkeratotic subjects with palmoplantar keratoderma. Fatty acids of triacylglycerols in normal tissues showed a characteristic pattern with a relative abundance of short-chain length and unsaturated fatty acids. Free fatty acid fraction was characterized by the predominance of saturated compounds. The relative amount of short-chain and monoene fatty acids in the hyperkeratotic stratum corneum was increased. These results seem to show a defect in the maturation of fatty acids in the living epidermis and present new evidence that the abnormality of lipid metabolism can influence the process of desquamation in stratum corneum

Parallel integral projection transform for straight electrode localization in 3-D ultrasound images

In surgical practice, small metallic instruments are frequently used to perform various tasks inside the human body. We address the problem of their accurate localization in the tissue. Recent experiments using medical ultrasound have shown that this modality is suitable for real-time visualization of anatomical structures as well as the position of surgical instruments. We propose an image- processing algorithm that permits automatic estimation of the position of a line-segment-shaped object. This method was applied to the localization of a thin metallic electrode in biological tissue. We show that the electrode axis can be found through maximizing the parallel integral projection transform that is a form of the Radon transform. To accelerate this step, hierarchical mesh-grid algorithm is implemented. Once the axis position is known, localization of the electrode tip is performed. The method was tested on simulated images, on ultrasound images of a tissue mimicking phantom containing a metallic electrode, and on real ultrasound images from breast biopsy. The results indicate that the algorithm is robust with respect to variations in electrode position and speckle noise. Localization accuracy is of the order of hundreds of micrometers and is comparable to the ultrasound system axial resolution

Diversity and Transparency for ECC

Generating and standardizing elliptic curves to use them in a cryptographic context is a hard task. In this note, we don’t make an explicit proposal for an elliptic curve, but we deal with the following issues. Security: We give a list of criteria that should be satisfied by a secure elliptic curve. Although a few of these criteria are incompatible, we detail what we think are the best choices for optimal security. Transparency: We sketch a way to generate a curve in a fully transparent way so that it can be trusted and not suspected to belong to a (not publicly known to be) vulnerable class. In particular, since the computational cost of verifying the output of such a process may be quite high, we sketch out the format of a certificate that eases the computations. We think that this format might deserve being standardized

Numerical evaluation of grouting scenarios for reducing water inflows in underground excavations – Goldcorp’s Éléonore mine study case

Water inflows through fracture networks are one of the many challenges that the Éléonore mine has to face. Although pregrouting of pilot holes during mine development has been proven to efficiently reduce water inflows into mine excavations, the actual design methods are empirical and can be optimized to increase grouting efficiency and decrease the associated costs. Optimization of the amount of cement needed for pre-grouting is achieved by designing the grouting approach based on the location of major faults around the excavations. Here, a base case finite-element numerical model and associated sensitivity analyses are used to simulate groundwater inflows into a stope, based on the Éléonore mining site characteristics. Simulations are conducted for testing various grout injection scenarios for various major fault locations around the stope. Sensitivity analyses have shown that for a fault located above the stope, the inflow reduction is greater when the zone between the fault and the stope is grouted instead of directly grouting the fault itself. Also, in the case of a fault intersecting a stope, the results have demonstrated that the fault itself should be grouted as widely as possible, instead of sealing only the immediate surroundings of the stope

Therapeutic protein transduction of mammalian cells and mice by nucleic acid-free lentiviral nanoparticles

The straightforward production and dose-controlled administration of protein therapeutics remain major challenges for the biopharmaceutical manufacturing and gene therapy communities. Transgenes linked to HIV-1-derived vpr and pol-based protease cleavage (PC) sequences were co-produced as chimeric fusion proteins in a lentivirus production setting, encapsidated and processed to fusion peptide-free native protein in pseudotyped lentivirions for intracellular delivery and therapeutic action in target cells. Devoid of viral genome sequences, protein-transducing nanoparticles (PTNs) enabled transient and dose-dependent delivery of therapeutic proteins at functional quantities into a variety of mammalian cells in the absence of host chromosome modifications. PTNs delivering Manihot esculenta linamarase into rodent or human, tumor cell lines and spheroids mediated hydrolysis of the innocuous natural prodrug linamarin to cyanide and resulted in efficient cell killing. Following linamarin injection into nude mice, linamarase-transducing nanoparticles impacted solid tumor development through the bystander effect of cyanid

Therapeutic protein transduction of mammalian cells and mice by nucleic acid-free lentiviral nanoparticles

The straightforward production and dose-controlled administration of protein therapeutics remain major challenges for the biopharmaceutical manufacturing and gene therapy communities. Transgenes linked to HIV-1-derived vpr and pol-based protease cleavage (PC) sequences were co-produced as chimeric fusion proteins in a lentivirus production setting, encapsidated and processed to fusion peptide-free native protein in pseudotyped lentivirions for intracellular delivery and therapeutic action in target cells. Devoid of viral genome sequences, protein-transducing nanoparticles (PTNs) enabled transient and dose-dependent delivery of therapeutic proteins at functional quantities into a variety of mammalian cells in the absence of host chromosome modifications. PTNs delivering Manihot esculenta linamarase into rodent or human, tumor cell lines and spheroids mediated hydrolysis of the innocuous natural prodrug linamarin to cyanide and resulted in efficient cell killing. Following linamarin injection into nude mice, linamarase-transducing nanoparticles impacted solid tumor development through the bystander effect of cyanide