Search results for "RATES"
showing 10 items of 1636 documents
Los prejuicios no percibidos y el caso Sócrates: un ejemplo paradigmático
2021
En un trabajo anterior defendimos que no se había prestado suficiente atención al procedimiento utilizado en el juicio contra Sócrates, sin que examináramos las causas de esa desatención. Ahora, tras analizarlas, llegamos a la conclusión de que ese procedimiento se habría malentendido completamente al haberse implementado un prejuicio no percibido. Habríamos extrapolado a ese procedimiento los presupuestos individualistas de los procedimientos vigentes hoy en día y, en consecuencia, habríamos estado sordos a lo que nos dice la tradición. Un ejemplo de sordera que podría ser muy útil para detectar otros casos semejantes de implementación de prejuicios no percibidos. In a previous work, we de…
Restoration of Clostridium difficile toxin-B-inhibited phospholipase D by phosphatidylinositol 4,5-bisphosphate.
1996
Receptor signalling to phospholipase D (PLD) in human embryonic kidney (HEK) cells stably expressing the m3 muscarinic acetylcholine receptor apparently involves Rho proteins. Since phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] has been recognized as an essential cofactor for PLD activity and since activated Rho proteins have been reported to stimulate the synthesis of PtdIns(4,5)P2, we studied whether in HEK cells PLD activity is regulated by PtdIns(4,5)P2 and, in particular, whether PtdIns(4,5)P2 can restore PLD activity inhibited by Clostridium difficile toxin B, which inactivates Rho proteins. Addition of MgATP to permeabilized HEK cells increased basal PLD activity and potentia…
Modulation of neuronal phospholipase D activity under depolarizing conditions
1999
Neuronal phospholipase D (PLD) activity was hypothesized to be involved in vesicle trafficking and endocytosis and, possibly, transmitter release. We here report that prolonged depolarization of rat hippocampal slices by potassium chloride (KCl) or 4-aminopyridine inhibited PLD activity. Similarly, PLD activity in rat cortical synaptosomes was significantly inhibited by depolarizing agents including veratridine and ouabain. Inhibition of calcium/calmodulin kinase II (CaMKII) which positively modulates synaptosomal PLD activity [Sarri et al. (1998) FEBS Lett. 440, 287-290] by KN-62 caused a further reduction of PLD activity in depolarized synaptosomes. Depolarization-induced inhibition of PL…
Inhibition of Receptor Signaling to Phospholipase D by Clostridium difficile Toxin B
1996
Rho proteins have been reported to activate phospholipase D (PLD) in in vitro preparations. To examine the role of Rho proteins in receptor signaling to PLD, we studied the effect of Clostridium difficile toxin B, which glucosylates Rho proteins, on the regulation of PLD activity in human embryonic kidney (HEK) cells stably expressing the m3 muscarinic acetylcholine receptor (mAChR). Toxin B treatment of HEK cells potently and efficiently blocked mAChR-stimulated PLD. In contrast, basal and phorbol ester-stimulated PLD activities were not or only slightly reduced. Cytochalasin B and Clostridium botulinum C2 toxin, mimicking the effect of toxin B on the actin cytoskeleton but without involvi…
A modified guanosine phosphoramidite for click functionalization of RNA on the sugar edge
2012
A propargyl containing guanosine phosphoramidite was synthesized and incorporated into siRNA, enabling click-ligation with an azido fluorophore onto the nucleobase sugar edge. Duplex stability was not affected by labeling at this new site, which allowed deconvolution of the effects of label, structure and attachment site on RNAi activity.
Power saturation of ESR signal in ammonium tartrate exposed to 60Co gamma-ray photons, electrons and protons.
2006
Abstract Marrale, M., Brai, M., Triolo, A., Bartolotta, A. and D'Oca, M. C. Power Saturation of ESR Signal in Ammonium Tartrate Exposed to 60Co γ-Ray Photons, Electrons and Protons. Radiat. Res. 166, 802–809 (2006). In this paper we present an investigation of the electron spin resonance (ESR) line shape of ammonium tartrate (AT) dosimeters exposed to radiation with different linear energy transfer (LET). We exposed our dosimeters to γ-ray photons (60Co), 7 MeV and 14 MeV initial energy electrons, and 19.3 MeV initial energy protons. The differences in the power saturation behavior of ESR spectra of AT irradiated with photons, electrons and protons could be correlated to the effective LET o…
Photoreceptor vitality in organotypic cultures of mature vertebrate retinas validated by light-dependent molecular movements
2006
AbstractVertebrate photoreceptor cells are polarized neurons highly specialized for light absorption and visual signal transduction. Photoreceptor cells consist of the light sensitive outer segment and the biosynthetic active inner segment linked by a slender connecting cilium. The function of mature photoreceptor cells is strictly dependent on this compartmentalization which is maintained in the specialized retinal environment. To keep this fragile morphologic and functional composition for further cell biological studies and treatments we established organotypic retina cultures of mature mice and Xenopus laevis. The organotypic retina cultures of both model organisms are created as co-cul…
Evidences of adaptive traits to rocky substrates undermine paradigm of habitat preference of the Mediterranean seagrass Posidonia oceanica
2015
AbstractPosidonia oceanica meadows are acknowledged as one of the most valuable ecosystems of the Mediterranean Sea. P. oceanica has been historically described as a species typically growing on mobile substrates whose development requires precursor communities. Here we document for the first time the extensive presence of sticky hairs covering P. oceanica seedling roots. Adhesive root hairs allow the seedlings to firmly anchor to rocky substrates with anchorage strength values up to 5.23 N, regardless of the presence of algal cover and to colonise bare rock without the need for precursor assemblages to facilitate settlement. Adhesive root hairs are a morphological trait common on plants li…
Molecular phylogeny of Metazoa (animals): monophyletic origin.
1995
The phylogenetic relationships within the kingdom Animalia (Metazoa) have long been questioned. Focusing on the lowest eukaryotic multicellular organisms, the metazoan phylum Porifera (sponges), it remained unsolved if they evolved multicellularity independently from a separate protist lineage (polyphyly of animals) of derived from the same protist group as the other animal phyla (monophyly). After having analyzed genes typical for multicellularity (adhesion molecules/receptors and a nuclear receptor), we present evidence that Porifera should be placed in the kingdom Animalia. We therefore suggest a monophyletic origin for all animals.
Fluorescence relaxation in the near-field of a mesoscopic metallic particle : distance dependence and role of plasmon modes
2008
International audience; We analytically and numerically analyze the fluorescence decay rate of a quantum emitter placed in the vicinity of a spherical metallic particle of mesoscopic size (i.e with dimensions comparable to the emission wavelength). We discuss the efficiency of the radiative decay rate and non–radiative coupling to the particle as well as their distance dependence. The electromagnetic coupling mechanisms between the emitter and the particle are investigated by analyzing the role of the plasmon modes and their nature (dipole, multipole or interface mode). We demonstrate that near-field coupling can be expressed in a simple form verifying the optical theorem for each particle …