Nuclear Charge Radius of

Collinear laser spectroscopy was performed on the isomer of the aluminium isotope ^{26m}Al. The measured isotope shift to ^{27}Al in the 3s^{2}3p ^{2}P_{3/2}^{○}→3s^{2}4s ^{2}S_{1/2} atomic transition enabled the first experimental determination of the nuclear charge radius of ^{26m}Al, resulting in R_{c}=3.130(15) fm. This differs by 4.5 standard deviations from the extrapolated value used to calculate the isospin-symmetry breaking corrections in the superallowed ß decay of ^{26m}Al. Its corrected Ft value, important for the estimation of V_{ud} in the Cabibbo-Kobayashi-Maskawa matrix, is thus shifted by 1 standard deviation to 3071.4(1.0) s.

Evidence suggesting interactions between immunodominant membrane protein Imp of Flavescence dorée phytoplasma and protein extracts from distantly related insect species.

AIMS: In this study, binding between the immunodominant membrane protein Imp of the 16SrV-D phytoplasma associated with Flavescence dorée disease (FD-Dp) and insect proteins of vectors and non-vectors of FD-Dp was tested. METHODS AND RESULTS: Six Auchenorrhyncha species, from distantly related groups were selected: Scaphoideus titanus, Euscelidius variegatus, Macrosteles quadripunctulatus, Zyginidia pullula (Cicadomorpha), Ricania speculum and Metcalfa pruinosa (Fulgoromorpha). The vector status of each species was retrieved from the literature or determined by transmission trials in this study. A His-tagged partial Imp protein and a rabbit polyclonal antibody were synthesized and used for Western and Far-Western dot Blot (FWdB) experiments. Total native and membrane proteins (MP) were extracted from entire bodies and organs (gut and salivary glands) of each insect species. FWdB showed decreasing interaction intensities of Imp fusion protein with total proteins from entire bodies of S. titanus, E. variegatus (competent vectors) and M. quadripunctulatus (non-vector), while no interaction signal was detected with the other three species (non-vectors). A strong signal detected upon interaction of FD-D Imp and MP from guts of closely related insects supports the role of this organ as the first barrier to ensure successful transmission. CONCLUSIONS: Our results showed that specific Imp binding, correlated with vector status, is involved in interactions between FD-Dp and insect proteins. SIGNIFICANCE AND IMPACT OF THE STUDY: Integrating knowledge on host-pathogen protein-protein interactions and on insect phylogeny would help to identify the actual range of vectors of phytoplasma strains of economic importance.

[Thrombin generation test: establishment of reference values according to age and tissue factor concentration is essential before implementation into the laboratory]. / Test de génération de thrombine: importance d'établir les valeurs de référence en fonction de l'âge et des concentrations en facteur tissulaire avant l'implémentation au laboratoire.

The calibrated and automated thrombinography (CAT) developed by H.C. Hemker is a simple and reproducible technique that can be potentially used in coagulation laboratories. This test is able to record the complete thrombin generation in vitro, giving an interesting approach in the evaluation of the haemostatic potential at the individual level. We aimed to implement this test in our laboratory to follow patients with haemorrhagic or thrombotic pathologies. Haemorrhagic and thrombotic disorders are incompletely explored by the coagulation tests used presently in routine labs. These tests don't indeed reflect the real haemostatic phenotype of the patient neither the individual response to haemostatic treatments. Furthermore, they don't have any predictive value for the occurrence of haemorrhage and/or thrombosis. We report here reference values we established in a population of children and adults in pre-analytical conditions easily applicable in coagulation labs. Platelet poor plasma is prepared by a double centrifugation and analyzed immediately or frozen at -80 degrees C for delayed analysis.

Redox signalling and the inflammatory response in rheumatoid arthritis.

Reactive oxygen species (ROS) are produced mainly during oxidative phosphorylation and by activated phagocytic cells during oxidative burst. The excessive production of ROS can damage lipids, protein, membrane and nucleic acids. They also serve as important intracellular signalling that enhances the inflammatory response. Many studies have demonstrated a role of ROS in the pathogenesis of inflammatory chronic arthropathies, such as rheumatoid arthritis. It is known that ROS can function as a second messenger to activate nuclear factor kappa-B, which orchestrates the expression of a spectrum of genes involved in the inflammatory response. Therefore, an understanding of the complex interactions between these pathways might be useful for the development of novel therapeutic strategies for rheumatoid arthritis.

Heterogeneity of second messenger levels in living cells.

Over the last years we have utilised chimeras from aequorin and green fluorescent protein (GFP) to monitor the dynamics of second messenger levels in living cells. In this contribution we address two problems, i.e. the complexity of Ca2+ handling by mitochondria and the localization of cAMP signalling. As to the first, we here demonstrate that physiological increases in mitochondrial Ca2+, monitored with selectively localized recombinant aequorin, concern a sub-population of organelles that is stably and selectively associated with the endoplasmic reticulum. As to cAMP, we describe the use of a novel probe to monitor its changes in living cells, that takes advantage of the phenomenon of fluorescence resonance energy transfer (FRET) between suitable GFPs linked to the regulatory and catalytic subunits of protein kinase A (PKA). When cAMP is low the two fluorophores are in close proximity and generate FRET while increasing levels of cAMP determine progressive reduction of FRET as the two subunits (linked to the GFPs) diffuse apart. We also demonstrate that by using such cAMP sensor, localized increase of this second messenger can be observed upon selective stimulation of plasma membrane receptors.

Mitochondria as biosensors of calcium microdomains.

The notion that the agonist-dependent increases in intracellular Ca2+ concentration, on ubiquitous signalling mechanism, occur with a tightly regulated spatio-temporal pattern has become an established concept in modern cell biology. As a consequence, the concept is emerging that the recruitment of specific intracellular targets and effector system mechanisms depends on exposure to local [Ca2+] that differs substantially from the mean [Ca2+]. A striking example is provided by mitochondria, intracellular organelles that have been overlooked for a long time in the field of calcium signalling due to the low affinity of their Ca(2+)-uptake pathways. We will summarize here some of the evidence indicating that these organelles actively participate in Ca2+ homeostasis in physiological conditions (with consequences not only for the control of their function, but also for the modulation of the complexity of calcium signals) because they have the capability to respond to microdomains of high [Ca2+] transiently generated in their proximity by the opening of Ca2+ channels.