A Novel Severe Acute Respiratory Syndrome Coronavirus Protein, U274, is transported to the Cell Surface and undergoes Endocytosis

The severe acute respiratory syndrome coronavirus (SARS-CoV) genome contains open reading frames (ORFs) that encode for several genes that are homologous to proteins found in all known coronaviruses. These are the replicase gene 1a/1b and the four structural proteins, nucleocapsid (N), spike (S), membrane (M), and envelope (E), and these proteins are expected to be essential for the replication of the virus. In addition, this genome also contains nine other potential ORFs varying in length from 39 to 274 amino acids. The largest among these is the first ORF of the second longest subgenomic RNA, and this protein (termed U274 in the present study) consists of 274 amino acids and contains three putative transmembrane domains. Using antibody specific for the C terminus of U274, we show U274 to be expressed in SARS-CoV-infected Vero E6 cells and, in addition to the full-length protein, two other processed forms were also detected. By indirect immunofluorescence, U274 was localized to the perinuclear region, as well as to the plasma membrane, in both transfected and infected cells. Using an N terminus myc-tagged U274, the topology of U274 and its expression on the cell surface were confirmed. Deletion of a cytoplasmic domain of U274, which contains Yxx and diacidic motifs, abolished its transport to the cell surface. In addition, U274 expressed on the cell surface can internalize antibodies from the culture medium into the cells. Coimmunoprecipitation experiments also showed that U274 could interact specifically with the M, E, and S structural proteins, as well as with U122, another protein that is unique to SARS-CoV.Web of Scienc

Directed evolution and predictive modelling of galactose oxidase towards bulky benzylic and unactivated secondary alcohols

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Precision in medicinal chemistry: Harnessing enzymes for advanced halogenation

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Cross-Reactivity and Anti-viral Function of Dengue Capsid and NS3-Specific Memory T Cells Toward Zika Virus

Zika virus (ZIKV), a flavivirus with homology to dengue virus (DENV), is spreading to areas of DENV hyper-endemicity. Heterologous T cell immunity, whereby virus-specific memory T cells are activated by variant peptides derived from a different virus, can lead to enhanced viral clearance or diminished protective immunity and altered immunopathology. In mice, CD8+ T cells specific for DENV provide in vivo protective efficacy against subsequent ZIKV infection. In humans, contrasting studies report complete absence or varying degrees of DENV/ZIKV T cell cross-reactivity. Moreover, the impact of cross-reactive T cell recognition on the anti-viral capacity of T cells remains unclear. Here, we show that DENV-specific memory T cells display robust cross-reactive recognition of ZIKV NS3 ex vivo and after in vitro expansion in respectively n = 7/10 and n = 9/9 dengue-immune individuals tested. In contrast, cross-reactivity toward ZIKV capsid is low or absent. Cross-reactive recognition of DENV or ZIKV NS3 peptides elicits similar production of the anti-viral effector mediators IFN-γ, TNF-α, and CD107a. We identify 9 DENV/ZIKV cross-reactive epitopes, 7 of which are CD4+ and 2 are CD8+ T cell epitopes. We also show that cross-reactive CD4+ and CD8+ T cells targeting novel NS3 epitopes display anti-viral effector potential toward ZIKV-infected cells, with CD8+ T cells mediating direct lyses of these cells. Our results demonstrate that DENV NS3-specific memory T cells display anti-viral effector capacity toward ZIKV, suggesting a potential beneficial effect in humans of pre-existing T cell immunity to DENV upon ZIKV infection

A human PrM antibody that recognizes a novel cryptic epitope on dengue E glycoprotein

10.1371/journal.pone.0033451PLoS ONE74

I. Total syntheses of bisanthraquinones through cascade reactions. II. Fluorine-18 radiochemistry to advance cancer imaging

(+)-Rugulosin, (+)-2,2'-epi-cytoskyrin A and the alleged rugulin, a family of naturally occurring modified bisanthraquinones have been synthesized via an expedient and extremely efficient route, herein named the “cytoskyrin cascade” which features alternate oxidation and Michael addition reactions. The alleged rugulin structure was proved to have been misassigned. Bisanthraquinone BE-43472B, an octacyclic molecule, has been synthesized by a concise route involving a key cascade sequence featuring a Diels-Alder reaction, a hemiketal formation and a nucleophilic aromatic ipso substitution which led to the formation of the requisite octacyclic framework in near quantitative yield. Further elaborations of this advanced intermediate via a selective installation of C-3 hydroxy group, a chemoselective removal of the superfluous C-2 oxygen and the installation of the requisite C-1 oxygen through an epoxidation/oxirane rearrangement, then led to the first total synthesis of this natural product, BE-43472B, and the determination of its previously unknown absolute configuration. A peptide selective for VCAM-1 has been successfully radiolabelled with 18F and evaluated in vitro and in vivo to determine its suitability as a PET tracer for the detection of cancer micrometastases. While it has binding selectivity and specificity for VCAM-1 as attested by the in vitro binding assay and serum stability, it lacks the binding affinity (Kd) necessary of a PET tracer. A novel “detagging” method for 18F-radiolabelling featuring a trans-esterification followed by an intramolecular O → N acyl transfer rearrangement using amino alcohols has been developed. Both commercially available solid phase resins and fluorous phase tag were found to be amenable to this chemistry, at least on model systems. An direct oxidative nucleophilic fluorination of electron-rich aromatic via a simple one-step protocol has been preliminarily developed. The synthesis of 4-[18F]fluorophenol was validated radiochemically

Total sysntheses of bisanthraquinones through cascade reactions 18F-radiochemistry to advance cancer imaging

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Effect of microchannel junction angle on two-phase liquid-gas Taylor flow

Two-phase liquid-gas Taylor flow triggered by blocking-squeezing mechanism was studied with different junction angle h microchannels, i.e. 20 , 45 , 90 , 135 and 160 , at various liquid (ethanol) and gas (He) flow rates. We experimentally investigated the effects of flow rates and h on the gas bubble VB and liquid slug VS volumes. A theoretical model was formulated for the quantitative predictions of bubble and slug sizes for different h and flow rates. Good agreements were obtained between theoretical predictions and experimental observations. The unit cell volume VU (VB + VS) decreased pronouncedly for the 20 channel with decreasing liquid or increasing gas flow rate, due to the slight increase in VB and large decrease in VS. In comparison, for the 45 , 90 , 135 and 160 channels with increasing liquid or decreasing gas flow rate, VU were less sensitive to fluid flow rate changes, due to the approximate cancellation between VB decrease and VS increase. For the 20 and 45 channels, it produced larger VU, due to larger VB and VS, when compared to the 90 channel. This is caused by the larger gas bubble throat width DN at the junction when h 90 ), DN is approximately equal to the gas channel width, with VB, VS and VU approximately the same as the 90 channel. With h 90 (i.e. 90 , 135 and 160 channels), as evident from the smaller VU, higher gas bubble density can be obtained when compared to h < 90 (i.e. 20 and 45 channels). Hitherto, this observation has not been realized, and the mechanics is first investigated here with the employment of extreme h (i.e. 20 and 160 ). A thorough understanding of the underlying mechanics affecting Taylor flow can facilitate its exploitation for controlled gas bubble and liquid slug generation. Our theoretical model facilitates the tuning of the channel designs and fluid flow rates to achieve the desired gas bubble and liquid slug sizes for specific applications.NMRC (Natl Medical Research Council, S’pore)Accepted versio

Asia economic crisis : opportunities and challenges in the banking sector.

The aim of this research is to explore the opportunities that have emerged for foreign banks and regional banks as a result of the Asian Economic Crisis. The factors that have led to the crisis and the aftermath of the crisis on the banking sector will be looked into. Interviews with banks in Singapore led to the identification of opportunities such as Mergers & Acquisitions, Strategic Alliances, Fee-based Income, Expansion & Restructuring of Operations