Search results for "Phosphor"

Spectroscopic studies of the origin of the radiation-induced degradation in phosphorous-doped optical fiber and preforms

2010

In this paper, we study the radiation-induced point defects related to the phosphorus element that is commonly used to improve the optical properties of silica-based glasses but is responsible of a dramatic increase in their radiation sensitivity. To this aim, the influence of x-ray irradiation on prototype phosphorus-doped canonical fibers and their related preforms was investigated by in situ radiation induced attenuation (RIA), optical absorption, and electron spin resonance (ESR) spectroscopy. The RIA spectra in the (1.5-5 eV) range, can be explained by the presence of at least three absorption bands induced by radiation exposure. Additionally the X-dose dependence of such bands was stu…

Impact de l'épandage des boues sur le phosphore dissous et particulaire des écoulements de surface

2003

Abstract The aim of this study was to assess the effect of land application of sewage sludge on phosphorus (P) losses during intense rainfall. Three rainfall simulations (40 mm h−1 of 30 min duration) were conducted on a field amended with sewage sludge. The overland flow water (OFW) was monitored and sampled every minute. The suspended solid, the dissolved and total phosphorus (respectively SS, TP and DP) concentrations were analysed. The forms of particulate bound P (PP) were investigated. Several results stem from this experiment: (a) sludge application induced a large increase in the DP content of the OFW; the concentrations obtained (0.15–0.57 mg l−1) were shown to result from desorpti…

Calcium, calmodulin-dependent protein phosphorylation in Neurospora crassa

1984

Abstract A calcium, calmodulin-dependent protein kinase activity has been partially purified by calmodulin-Sepharose affinity chromatography from the soluble fraction of Neurospora crassa . The phosphorylated peptide has an apparent molecular mass on SDS-polyacrylamide gel of 47 kDa. The apparent half maximal phosphorylation is obtained after 1.5 min at 30° C in the presence of calcium and calmodulin. The apparent half maximal activation of the phosphorylation is obtained at 1 μM calcium, and 0.1 or 0.2 μM calmodulin from bovine brain or Neurospora , respectively. The 32 P incorporation is enhanced about 10-fold by calmodulin.

TRAIL signalling regulation by ezrin

2011

Background and Aim: TRAIL has sparked a growing interest in oncology due to its ability to selectively trigger cancer cell death while sparing normal cells. The Fas/actin association through ezrin, a member of the ERM protein family, has been reported to regulate early steps of Fas-mediated apoptosis. In this project, we addressed the role of ezrin regarding TRAIL-induced cell death in B lymphoma cell lines, or adherent cancer cell lines (HeLa WT, HCT116, SW480). Methods: Molecular and biochemical approaches were employed to study the relevance of ezrin and its phosphorylation status in TRAIL signaling. Results: We found that ezrin displays a negative function towards TRAIL- and Fas-mediate…

Restitution de l’atelier 1 : Services écosystémiques recherchés relatifs aux cycles C,N ,P

2013

Bacillus consortium positively impacts arbuscular mycorrhizal fungi community, plant phosphate nutrition and potato yield in Solanum tuberosum cv. Ja…

2022

Many agricultural soils are naturally poor in plant available phosphorus (P), although total P stocks can exceed plant requirements by more than 100-fold. The reason for such apparent contradiction is that P is complexed under organic and inorganic forms, but only free inorganic orthophosphate (Pi) ions are available to plants and soil organisms. The high immobility of Pi in soil, the low soil solution circulation associated with a rapid root absorption lead to the development of a depletion zone around the roots. As a consequence, P is frequently a limiting factor for plant growth and development.Arbuscular mycorrhizal (AM) fungi are estimated to colonize the vast majority of crop plants a…

Phosphorus tolerance of an hypermycorrhizal mutant of Medicago truncatula

2010

International audience

Coopération entre des bactéries solubilisatrices de phosphate et le champignon mycorhizien à arbuscule Rhizophagus irregularis dans la nutrition phos…

2019

National audience; Le phosphore est un élément essentiel pour le développement des plantes. Néanmoins, la majorité des ions phosphate est incorporée dans des structures organiques (Po) et inorganiques (Pi) insolubles qui rende cet élément très peu disponible pour les plantes et en particulier pour la pomme de terre (Solanum tuberosum). Dans les sols, le phytate (molécule de réserve phosphatée des plantes), est une source essentielle. Pour accéder au phosphate, les plantes ont développé des symbioses mutualistes à bénéfices réciproques avec des microorganismes de la rhizosphère capables d’extraire le P. Dans ce contexte, les objectifs de cette étude étaient de i) déterminer si la disponibili…

Post-translational Modifications in Plant Nuclear Signaling: Novel Insights Into Responses to Environmental Changes

2019

Just imagine a Plant Science professor in front of a classroom full of interested and attentive students. Imagine what their answers to this intriguing question would be: “What are, according to you, the functions ensured by the plant cell nucleus?” It would be very surprising if some of them would answer cell signaling in response to biotic and abiotic stresses or developmental processes. Most of them would probably answer according to a classical point of view: DNA replication or gene expression. Hence it is still admitted in recent publications (see for instance Fedorenko et al., 2010) that molecules smaller than 40 kDa can diffuse freely across the nuclear envelope pores. However, Pauly…

Unusual activity pattern of leucine aminopeptidase inhibitors based on phosphorus containing derivatives of methionine and norleucine

2010

Ligands containing bulky aliphatic P1 residues exhibit a high affinity towards cytosolic leucine aminopeptidase, a bizinc protease of biomedical significance. According to this specificity, a series of phosphonic and phosphinic compounds have been put forward as novel putative inhibitors of the enzyme. These phosphonic and phosphinic compounds were derivatives of methionine and norleucine as both single amino acids and dipeptides. The designed inhibitors were synthesised and tested towards the peptidase isolated from porcine kidneys using an improved separation procedure affording superior homogeneity. Unexpectedly, organophosphorus derivatives of methionine and norleucine exhibited moderat…