882 research outputs found

    Gold Nanoparticles Decorated with Sialic Acid Terminated Bi-antennary N-Glycans for the Detection of Influenza Virus at Nanomolar Concentrations

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    Gold nanoparticles decorated with full-length sialic acid terminated complex bi-antennary N-glycans, synthesized with glycans isolated from egg yolk, were used as a sensor for the detection of both recombinant hemagglutinin (HA) and whole influenza A virus particles of the H1N1 subtype. Nanoparticle aggregation was induced by interaction between the sialic acid termini of the glycans attached to gold and the multivalent sialic acid binding sites of HA. Both dynamic light scattering (DLS) and UV/Vis spectroscopy demonstrated the efficiency of the sensor, which could detect viral HA at nanomolar concentrations and revealed a linear relationship between the extent of nanoparticle aggregation and the concentration of HA. UV/ Vis studies also showed that these nanoparticles can selectively detect an influenza A virus strain that preferentially binds sialic acid terminated glycans with a(2!6) linkages over a strain that prefers glycans with terminal a(2!3)-linked sialic acids

    Spectrin phosphorylation and shape change of human erythrocyte ghosts.

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    The prevalence of polypharmacy in elderly attenders to an emergency department - a problem with a need for an effective solution

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    We studied the prevalence of polypharmacy in attenders aged 75 years and over to an emergency department (ED) in North London over a period of 1 month. We identified 467 patients in this age group. Analysis of medications being prescribed revealed at least 82 patients on medication with the potential for adverse interaction. There is a need for ED-initiated strategies to identify interactions and for pathways to allow for medication review

    A ruthenium(II) polypyridyl complex disrupts actin cytoskeleton assembly and blocks cytokinesis

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    The dinuclear Ru(II) complex [(Ru(phen) 2 ) 2 (tpphz)] 4+ (phen = 1,10-phenanthroline, tpphz = tetrapyridophenazine) “RuRuPhen” blocks the transformation of G-actin to F-actin filaments with no disassembly of pre-formed F-actin. Molecular docking studies indicate multiple RuRuPhen molecules bind to the surface of G-actin but not the binding pockets of established actin polymerisation inhibitors. In cells, addition of RuRuPhen causes rapid disruption to actin stress fibre organisation, compromising actomyosin contractility and cell motility, due to this effect RuRuPhen interferes with late-stage cytokinesis. Immunofluorescent microscopy reveals that RuRuPhen causes cytokinetic abscission failure by interfering with ESCRT complex recruitmen

    Integrated Late Eocene-Oligocene Stratigraphy of the Alabama Coastal Plain: Correlation of Hiatuses and Stratal Surfaces to Glacioeustatic Lowerings

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    We integrated strontium and oxygen isotopic, biostratigraphic, and magnetostratigraphic studies of two upper Eocene-Oligocene boreholes drilled near Bay Minette and St. Stephens Quarry (SSQ), Alabama. Continuous coring provided fresh, unweathered material for magnetostratigraphic studies, minimizing problems reported from nearby outcrops. Difficulties with each technique were encountered because of diagenesis, absence of marker fossils, and the presence of unconformities; however, by integrating results from isotopic stratigraphy, biostratigraphy, and magnetostratigraphy, we correlated these relatively shallow-water deposits to the geomagnetic polarity time scale (GPTS). At the SSQ borehole, the upper Eocene to lower Oligocene section is apparently complete within our stratigraphic resolution (0.2-0.5 m.y.), allowing us to estimate the ages of several stratal surfaces. Late Eocene Sr isotope age estimates are as expected at the SSQ borehole, but Oligocene ages are ~1 m.y. older than expected due to diagenesis. At the Bay Minette borehole, a latest Eocene-earliest Oligocene and a late early Oligocene hiatus were detected. We correlate these two hiatuses and stratal surfaces at SSQ with global δ^18O increases inferred to represent glacioeustatic lowerings and with evidence for hiatuses on other continental margins: (1) a distinct disconformity at the base of the Chickasawhay Limestone at both boreholes and a hiatus at Bay Minette correlates with a global δ^18O increase; we revise the age of this surface (equivalent to the TB 1.1 sequence boundary) making it ~2 m.y. older than previously reported; and (2) a surface at the top of the Shubuta Member (lowermost Oligocene) has been interpreted both as a condensed section and a disconformity; this surface at SSQ and a hiatus at Bay Minette correlate with a sharp global δ^18O increase and with hiatuses on the New Jersey and Irish margins. The timing of the hiatuses and stratal surfaces correlates with the inflection of the δ^18O increases and not with the maximum values, supporting models that indicate that unconformities form during the maximum rates of sea level fall

    Simultaneous Activation of Complement and Coagulation by MBL-Associated Serine Protease 2

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    The complement system is an important immune mechanism mediating both recognition and elimination of foreign bodies. The lectin pathway is one pathway of three by which the complement system is activated. The characteristic protease of this pathway is Mannan-binding lectin (MBL)-associated serine protease 2 (MASP2), which cleaves complement proteins C2 and C4. We present a novel and alternative role of MASP2 in the innate immune system. We have shown that MASP2 is capable of promoting fibrinogen turnover by cleavage of prothrombin, generating thrombin. By using a truncated active form of MASP2 as well as full-length MASP2 in complex with MBL, we have shown that the thrombin generated is active and can cleave both factor XIII and fibrinogen, forming cross-linked fibrin. To explore the biological significance of these findings we showed that fibrin was covalently bound on a bacterial surface to which MBL/MASP2 complexes were bound. These findings suggest that, as has been proposed for invertebrates, limited clotting may contribute to the innate immune response
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