Direct electrochemical detection of PB1-F2 protein of influenza A virus in infected cells

International audienceInfluenza virus represents a major concern of human health and animal production. PB1-F2 is a small proapoptotic protein supposed to contribute to the virulence of influenza A virus (IAV). However, the molecular mechanism of action of PB1-F2 is still unclear.PB1-F2 expression and behavior during the viral cycle is difficult to follow with classical biochemical methods. In this work we have developed an electrochemical biosensor based on immuno-detection system for quantification of PB1-F2 protein in infected cell. The electrochemical immunosensor was based on conducting copolypyrrole integrating ferrocenyl group as redox marker for enhancing signal detection. A specific anti-PB1-F2 monoclonal antibody was immobilized on the copolypyrrole layer via biotin-streptavidin system. We demonstrate that this electrochemical system sensitively detect purified recombinant PB1-F2 over a wide range of concentrations from 5 nM to 1.5 mu M. The high sensor sensitivity allowed the detection of PB1-F2 in lysates of infected cells confirming that PB1-F2 is expressed in early stages of viral cycle. The immunosensor developed shows enhanced performances for the evaluation of PB1-F2 protein concentration in biological samples and could be applied for studying of PB1-F2 during influenza virus infection

Amplification of the electrochemical signal of an olfactory receptor based biosensor by in situ generated gold nanoparticles

International audienceIn this work we present a biosensor based on olfactory receptors as a new bioelectronic device for detecting the presence and for measuring the concentration of specific odorants. To increase the surface of transducers, and consequently amplify the electrochemical signal, we generated gold nanoparticles on the surface of gold electrode. The characterization of the nanoparticles modified electrode surface allow to determine an increase of the surface area by a factor of 2.6 +/-. 0.4 (n = 4). Nanosomes from yeast containing olfactory receptor OR1740 with a cmyc tag were put in contact with the anti-cmyc antibody modified electrodes. Immobilization of nanosomes led to an increase in charge transfer resistance. This effect is amplified in the presence of gold nanoparticles by a factor of 3 +/- 0.5

Notes on the Topology of Analytic Sets (Geometry of Manifolds)

Deep Vein Thrombosis (DVT) and the associated condition of Pulmonary Embolism (PE) are the most common cause of unexpected death in developed nations. DVT is an internal clot formed in one of the body's deep veins, typically in the leg. If a part of the clot breaks free and moves into the lung, it can lead to pulmonary embolism (PE) which is often fatal. D-dimer is a recognised marker for the diagnosis of thrombus and is routinely used by skilled technical staff as part of an ELISA technique in hospital laboratories. Current D-dimer point-of-care tests are not sufficiently quantitative to allow them to be used to exclude DVT/PE. As a consequence, clinicians need to rely on the use of expensive Doppler ultrasound imaging (DUS), creating additional pressure on national health services. The DUS examination can take several days, during which time heparin is required to be administered to the patient. There is increasing in the development of low cost Lab-on-a-chip systems that will allow chemical and biological processing by non-specialist staff. A low cost, easy to use, portable and quantitative device for DVT/PE would be highly desirable since it would provide reliable diagnosis and aid faster treatment and recovery as well as lower healthcare provider costs

Series of Mn Complexes Based on N-Centered Ligands and Superoxide - Reactivity in an Anhydrous Medium and SOD-Like Activity in an Aqueous Medium Correlated to MnII/MnIII Redox Potentials

Two crystal structures are described in this article: (a) the structure of a monomeric MnII complex with the tridentate N-centered N3 ligand tris[(1-methyl-2-imidazolyl)methyl]amine (TMIMA) ([MnII(TMIMA)2]2+); and (b) the structure of a monomeric MnIII complex with the tridentate N-centered N2O ligand 2-{[(1-methyl-2-imidazolyl)methyl]amino}phenolate (PI–)2 ([MnIII(PI)2]+) (5). The latter was isolated both in the MnII and in the MnIII state, although only MnIII crystals were successfully grown. They are part of a series of Mn complexes prepared as SOD mimics, namely [Mn(BMPG)(H2O)]+ (2) {BMPG = N,N-bis[(6-methyl-2-pyridyl)methyl]glycinate}, [Mn(IPG)(MeOH)]+ (3) {IPG = N-[(1-methyl-2-imidazolyl)methyl]-N-(2-pyridylmethyl)glycinate}, [Mn(BIG)(H2O)2]+ (4) {BIG = N,N-bis[(1-methyl-2-imidazolyl)methyl]glycinate}. The reactivity of MnII complexes 1 and 2 in an anhydrous medium is described and compared to that of complexes 3 and 4, the data for which was previously published. The cyclic voltammograms of the whole complex series were recorded in an aqueous medium (collidine buffer). Their SOD-like activities were estimated by the McCord–Fridovich test (IC50 with 22 μM cytc FeIII: 1.6 ± 0.1 μMol L–1 for 1, 1.2 ± 0.5 μmol L–1 for 2, 3.0 ± 0.2 μmol L–1 for 3, 3.7 ± 0.6 μmol L–1 for 4, 0.8 ± 0.1 μmol L–1 for 5). IC50 values were converted into the corresponding kinetic constant kMcCF values. A linear correlation between Ea and log(kMcCF) was obtained, indicating that in this series the conversion to MnIII is probably the rate-limiting step. This is of substantial importance for further Mn–SOD mimic design in this serie