17 research outputs found

    ApoA-I is able to enhance DV infectivity.

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    <p>DV/SFM was pre-incubated with an increasing volume of supernatants collected at 2 dpt from AD293 cells transfected with pApoAI-FLAG and grown in serum-free DMEM (ApoAI-FLAG/SFM) (A) or pre-incubated with human delipidated ApoA-I (De-ApoAI) from <i>Calbiochem</i> for 1 h at 4°C, followed by infection of U937 cells at an MOI of 0.1. Total RNA was extracted at 1 dpi, and viral replication was measured by real-time PCR. The results represent the average standard deviation of three independent experiments. NS, no significance; **p<0.01; ***p<0.001.</p

    Co-precipitation of DV with ApoA-I.

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    <p>(A) Vero cells were infected with DV at a MOI of 1 and culture medium were changed to DMEM with 10% human serum HS (HSM) at 2 dpi. The mock-infected cells by DMEM was used as a control and also subjected to the same medium change. Culture supernatants were harvested at 7 dpi and purified by sucrose cushion ultracentrifugation (UC). The virus pellets were resuspended in serum-free DMEM. Presence of ApoA-I was analyzed by Western blotting using anti-ApoA-I antibody. (B) Human serum was added into DV/SFM to a final concentration of 10% and the mixture was incubated at 4° for 1 hour, followed by sucrose cushion ultracentrifugation. The pellets were analyzed by Western blotting using anti-ApoA-I and anti-E antibodies respectively. (C) Co-immunoprecipitation of ApoA-I with DV. AD-293 cells were transfected with a plasmid expressing FLAG-tagged ApoA-I (pApoAI-FLAG) and cultured in serum-free DMEM. At 3 dpt, secreted ApoA-I in the culture supernatant was purified with anti-FLAG M2 Affinity Gel. The resulting ApoAI-FLAG/M2 beads were washed twice with 1×TBS and incubated with DV/SFM at 4°C for over night. The co-immunoprecipitates were eluted and detected by Western blotting with anti-E and anti-FLAG antibodies. As a control, co-immunoprecipitation was also performed using the supernatant from cells transfected with empty vector p3×FLAG-CMV-14 (pFLAG). M, pre-stained protein marker.</p

    Interaction of ApoA-I and DV prior to infection is important for enhancement of virus infectivity.

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    <p>(A) U937 cells were infected with DV/SFM that was pre-incubated with the serum-free supernatant from ApoAI-FLAG expressing cells (ApoAI-FLAG/SFM) at 4°C for 1 hour before infection. (B) U937 cells were infected with DV/SFM in which ApoAI-FLAG/SFM was added at the time of infection. (C) U937 cells were pre-incubated with ApoAI-FLAG/SFM or De-ApoAI at 37°C for 1 h, followed by washing with 1×PBS and infection with DV/SFM. All infections were performed at an MOI of 0.1. Total RNA was extracted at 1 dpi and viral replication was measured by real-time PCR. The results represent the average standard deviation of three independent experiments. NS, no significance; ***p<0.001.</p

    ApoA-I promotes DV attachment/entry.

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    <p>Huh-7 cells infected with DV/SFM, DV/HSM or DV/ApoAI-FLAG were harvested at 30 minutes postinfection. Dengue antigen on the surface of infected cells was detected by indirect immunofluorescence assay and the percentage of DV-bound cells was analyzed by FACS.</p

    Down-regulation of SR-BI reduces DV infection in Huh-7 cells.

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    <p>(A) U937 cells and (B) Huh-7 cells were transfected with siRNA CTL or siRNA SR-BI. At 2 dpt, U937 cells and Huh-7 cells were infected with DV/SFM or DV/HSM at an MOI of 0.1. Total RNA was extracted at 1 dpi. Viral replication was measured by real-time PCR. The results represent the average standard deviation of three independent experiments. NS, no significance; **p<0.01. (C) Knockdown of SR-BI by siRNA. At 2 dpt, Huh-7 cell lysates were prepared and analyzed by Western blotting using anti-SR-BI and anti-Actin antibodies. The relative band density of Western blotting was analyzed with Image J.</p

    Human serum enhances infectivity of DV.

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    <p>(A) U937, (B) PBMCs, (E) Huh7 and (F) HepG2 cells were infected with DV collected from infected Vero cells cultured in serum-free medium (DV/SFM) or DV/SFM containing 10% human serum (DV/HSM) at an MOI of 0.1. Total RNA was extracted at 1 dpi, 2 dpi, 3 dpi for infected U937 cells respectively, and at 1 dpi for other infected cells. Viral replication was measured by real-time PCR. The results represent the average standard deviation of three independent experiments. NS, no significance; *p<0.05; **p<0.01; ***p<0.001. (C) DV/SFM and DV/HSM were ultracentrifuged (UC) over a 30% sucrose cushion, and resulting virus pellets (UC DV/SFM and UC DV/HSM) were resuspended in serum-free medium followed by infection of PBMCs. At 3 dpi, virus infection of cells was observed by IFA and virus RNA copy number was measure by real-time PCR. (D) Detection of dengue IgG antibodies in human serum. Dengue IgG ELISA kit (<i>Abnova</i>) was used to measure dengue IgG antibodies in the human pooled serum, and results were presented as antibody index (Ab index) values, which were calculated by the value of OD450 of the tested sample divided by the cut-off value that was generated from the calibrator in the kit. Ab index <0.9, no detectable IgG antibody to DV; 0.9–1.1, borderline positive; >1.1, detectable IgG antibody to DV. Positive Control (CTL) and negative control (CTL) are supplied in the kit.</p

    ZnO Nanorod-Induced Heteroepitaxial Growth of SOD Type Co-Based Zeolitic Imidazolate Framework Membranes for H<sub>2</sub> Separation

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    Up to now, the fabrication of well-intergrown Co-based zeolitic imidazolate framework (ZIF) membranes on porous tubular supports is still a major challenge. We report here a heteroepitaxial growth for preparing well-intergrown Co-based ZIFs (ZIF-67 and ZIF-9) tubular membranes with high performance and excellent thermal stability by employing a thin layer of ZnO nanorods acting as both nucleation centers and anchor sites for the growth of metal–organic framework membranes. The results show that well-intergrown Co-ZIF-67 and Co-ZIF-9 membranes are successfully achieved on the ZnO nanorod-modified porous ceramic tubes. This highly active heteroepitaxial growth may be attributed to the fact that the (Zn,Co) hydroxy double salt intermediate produced in situ from ZnO nanorods acts as heteroseeds and enables the uniform growth of Co-based membranes. The H<sub>2</sub>/CO<sub>2</sub> selectivity of the as-prepared Co-ZIF-9 tubular membrane could reach about 23.8 and the H<sub>2</sub>/CH<sub>4</sub> selectivity of Co-ZIF-67 tubular membrane is as high as 45.4. Moreover, the membranes demonstrate excellent stability because of the ZnO nanorods as linkers between the membrane and substrate

    Pump-locked microcavity Brillouin laser

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    Microcavity-based microlasers are the kernel light sources for integrating photonics and optoelectronics. The traditional pump light frequency locking mainly utilizes a complex system with optoelectronic feedback, which requires a high-cost narrow-linewidth pump laser and limits the application of microlasers in integrated optoelectronic systems. We propose to utilize Rayleigh scattering of microcavities to lock the frequency of the pump laser to the resonant frequency of the laser microcavity with an all-optical method. While compressing the linewidth of the pump laser, it can greatly improve the long-term stability of the optically pumped microcavity laser. In the experiment, the linewidth of the semiconductor pump laser is compressed from the MHz level to the kHz level. The microcavity Brillouin laser achieves an ultra-narrow intrinsic linewidth of 100 Hz, with an ultra-low frequency noise of 35 Hz2/Hz. The constructed microlaser obtains a locking time up to 1 hour, which does not require any temperature control or vibration isolation of the laser system. This work is the first demonstration to achieve an optically pump-locked microcavity Brillouin laser, which provides a stable and reliable low-cost experimental platform for ultra-narrow linewidth lasers, precision laser sensors, microwave-photonic signal synthesizer, and optomechanical systems

    Zika virus as an oncolytic treatment of human neuroblastoma cells requires CD24

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    <div><p>Neuroblastoma is the second most common childhood tumor. Survival is poor even with intensive therapy. In a search for therapies to neuroblastoma, we assessed the oncolytic potential of Zika virus. Zika virus is an emerging mosquito-borne pathogen unique among flaviviruses because of its association with congenital defects. Recent studies have shown that neuronal progenitor cells are likely the human target of Zika virus. Neuroblastoma has been shown to be responsive to infection. In this study, we show that neuroblastoma cells are widely permissive to Zika infection, revealing extensive cytopathic effects (CPE) and producing high titers of virus. However, a single cell line appeared poorly responsive to infection, producing undetectable levels of non-structural protein 1 (NS1), limited CPE, and low virus titers. A comparison of these poorly permissive cells to highly permissive neuroblastoma cells revealed a dramatic loss in the expression of the cell surface glycoprotein CD24 in poorly permissive cells. Complementation of CD24 expression in these cells led to the production of detectable levels of NS1 expression after infection with Zika, as well as dramatic increases in viral titers and CPE. Complementary studies using the Zika virus index strain and a north African isolate confirmed these phenotypes. These results suggest a possible role for CD24 in host cell specificity by Zika virus and offer a potential therapeutic target for its treatment. In addition, Zika viral therapy can serve as an adjunctive treatment for neuroblastoma by targeting tumor cells that can lead to recurrent disease and treatment failure.</p></div
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