Secondary bacterial infection is a common complication in severe influenza virus infections. During the H1N1 pandemic of 2009, increased mortality was observed among healthy young adults due to secondary bacterial pneumonia, one of the most frequent bacterial species being (Spn). Previous studies in mice and ferrets have suggested a synergistic relationship between Spn and influenza viruses.
View Article and Find Full Text PDFThree-dimensional imaging is a powerful tool for examining the spatial distribution of intracellular molecules like nucleic acids, proteins, and organelles in cells and tissues. Multicolor fluorescence imaging coupled with three-dimensional spatial information provide a platform to explore the relationship between different cellular features and molecules. We have previously developed a pipeline to study the intracellular localization of influenza virus genomic segments within an infected cell.
View Article and Find Full Text PDFThe influenza A virus (IAV) genome consists of eight negative-sense viral RNA (vRNA) segments that are selectively assembled into progeny virus particles through RNA-RNA interactions. To explore putative intersegmental RNA-RNA relationships, we quantified similarity between phylogenetic trees comprising each vRNA segment from seasonal human IAV. Intersegmental tree similarity differed between subtype and lineage.
View Article and Find Full Text PDFHuman-to-human transmission of influenza viruses is a serious public health threat, yet the precise role of immunity from previous infections on the susceptibility to airborne infection is still unknown. Using the ferret model, we examined the roles of exposure duration and heterosubtypic immunity on influenza transmission. We demonstrate that a 48 hour exposure is sufficient for efficient transmission of H1N1 and H3N2 viruses.
View Article and Find Full Text PDFNat Rev Microbiol
April 2021
Immunity to influenza viruses can be long-lived, but reinfections with antigenically distinct viral strains and subtypes are common. Reinfections can boost antibody responses against viral strains first encountered in childhood through a process termed "original antigenic sin." It is unknown how initial childhood exposures affect the induction of antibodies against the hemagglutinin (HA) stalk domain of influenza viruses.
View Article and Find Full Text PDFChikungunya virus (CHIKV) is a mosquito-borne alphavirus responsible for several significant outbreaks of debilitating acute and chronic arthritis and arthralgia over the past decade. These include a recent outbreak in the Caribbean islands and the Americas that caused more than 1 million cases of viral arthralgia. Despite the major impact of CHIKV on global health, viral determinants that promote CHIKV-induced disease are incompletely understood.
View Article and Find Full Text PDFObjective: People living with HIV in high-resource settings suffer severe levels of food insecurity; however, limited evidence exists regarding dietary intake and sub-components that characterize food insecurity (i.e. food quantity, quality, safety or procurement) in this population.
View Article and Find Full Text PDFThe synthetic biology toolbox lacks extendable and conformationally controllable yet easy-to-synthesize building blocks that are long enough to span membranes. To meet this need, an iterative synthesis of α-aminoisobutyric acid (Aib) oligomers was used to create a library of homologous rigid-rod 310-helical foldamers, which have incrementally increasing lengths and functionalizable N- and C-termini. This library was used to probe the inter-relationship of foldamer length, self-association strength, and ionophoric ability, which is poorly understood.
View Article and Find Full Text PDFHelical peptide foldamers rich in α-aminoisobutyric acid (Aib) act as peptaibol-mimicking ionophores in the phospholipid bilayers of artificial vesicles. Racemic samples of these foldamers are more active than their enantiopure counterparts, which was attributed to differing propensities to form aggregates with crystal-like features in the bilayer.
View Article and Find Full Text PDFAmino-substituted dipyrido[3,2-a:2',3'-c]phenazine (L(1)) and dimethyl-dipyrido[3,2-a:2',3'-c]phenazine (L(2)) have been investigated as: (i) chromophores in cyclen-based ligands for lanthanide(III) ions; (II) ancillary co-ligands in cyclometalated iridium(III) complexes; (III) bridging, linker units in covalently linked, water-soluble bimetallic lanthanide(III) iridium(III) hybrid complexes. The dipyrido[3,2-a:2',3'-c]phenazine (dppz) derivatives can act as sensitising chromophores (λ(ex) 400 nm) for Yb(III), resulting in characteristic near-IR emission at 950-1050 nm. The incorporation of dppz-type ligands into cyclometalated Ir(III) complexes of the general type [Ir(epqc)(2)(L(n))](PF(6)) (where epqc = ethylphenylquinoline carboxylate) gave luminescent species with solvent-sensitive emission properties.
View Article and Find Full Text PDFA new method for assessing the topology of metallosupramolecular assemblies using pyrene-appended ligands is reported. Two potentially tetradentate ligands containing one (L(1)) and two (L(2)) terminal pyrene moieties were synthesised and their complexes with Cu(+) and Cd(2+) were characterised. Photophysical measurements demonstrate that in [Cu(2)(L(1))(2)](2+), [CdL(1)](2+) and [Cu(2)(L(2))(2)](2+) the emission spectra are dominated by monomeric emission but in the cadmium complex of L(2) (where the pyrene units are in close proximity) a quenching of the luminescence coupled with weak emission at 540 nm is indicative of excimer formation.
View Article and Find Full Text PDFThe syntheses of four new ligands based upon 3-picolyl functionalised amino anthraquinone (AQ) chromophores are described via a one-pot reductive amination procedure giving the desired ligands L1-L4 (L1, 1-(3-picolylamino)anthracene-9,10-dione; L2, 1-hydroxy-4-(3-picolylamino)anthracene-9,10-dione; L3, 1,4-bis(3-picolylamino)anthracene-9,10-dione; L4, 1,5-bis(3-picolylamino)anthracene-9,10-dione). Each ligand was characterised in solution via(1)H and (13)C{(1)H} NMR, with three examples giving single crystal X-ray diffraction data. The structures confirmed the proposed formulations and also revealed the presence of intramolecular H-bonding between the quinone and secondary amine units.
View Article and Find Full Text PDFUV-visible titrations, (1)H NMRD experiments and molecular docking studies show that emissive anthraquinone appended dimetallic lanthanide complexes bind to DNA. The strength of binding and the observed relaxivity behaviour depend on the nature of the substituted anthraquinone core.
View Article and Find Full Text PDFA novel Ru(II) sensitiser A597 containing the 4,4'-dioctylamido-2,2'-bipyridine ancillary ligand is synthesised without the need for purification steps. It shows an irreversible oxidation at 0.92 V in the cyclic voltammogram and an absorbtion at 539 nm in the UV-vis spectrum corresponding to an (1)MLCT transition.
View Article and Find Full Text PDFResponsive lanthanide complexes demonstrate differentiated modulated luminescence output upon exposure to metal di-cations in aqueous solution.
View Article and Find Full Text PDFThe syntheses of two anthraquinone-derived tetraaza macrocyclic ligands (L1 via 1-amino-9,10-anthraquinone and L2 via 1-amino-4-hydroxy-9,10-anthraquinone) together with their corresponding LnIII complexes, Ln-L1/2 (Ln = NdIII, GdIII, ErIII, YbIII), are described. Both Ln-L1 (lambda(max) approximately 380 nm) and Ln-L2 (lambda(max) approximately 450 nm) complexes absorb in the visible region with good extinction coefficients (epsilon(vis) > 2 x 10(3) M-1 cm-1). Phosphorescence measurements on Gd-L1/2 at 77 K allowed the ligand-centred triplet states to be estimated at ca.
View Article and Find Full Text PDFRhenium complexes functionalised with thioester-terminated alkyl chains can be attached to gold nanoparticles to yield water-soluble, visibly luminescent Re-GNP hybrid conjugates.
View Article and Find Full Text PDFA diamino-functionalised cryptate can react irreversibly with butanal in water, in the presence of an excess of a metal ion, to form a cyclised bis-aminal complex, which displays metal-dependent luminescence properties.
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