17 research outputs found

    Rapid production of therapeutic proteins using plant system

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    Plant molecular farming is simply defined as the production of proteins therapeutics (PT) in plants, which involves transient gene expression in plants and purification of expressed protein to a great scale for diagnosis, treatment and other applications.  This is therapid,economical, safe and reproducible approach for the production of PTas compared to bacterial and mammalian systems. Protein yield and post-translational modifications are the major roadblocks that can be overcome byhigh expression strategies includes over expression constructs, suitable plant host systems and glycoengineering of proteins. The inherent ability of ideally producing safe, functional protein is the most striking phenomenon recognized by the pharmaceutical industries and developed many therapeutic products within few weeks to meet escalating demands during pandemic/epidemic outbreaks recentl

    Yeast expressed recombinant Hemagglutinin protein of Novel H1N1 elicits neutralising antibodies in rabbits and mice

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    Currently available vaccines for the pandemic Influenza A (H1N1) 2009 produced in chicken eggs have serious impediments viz limited availability, risk of allergic reactions and the possible selection of sub-populations differing from the naturally occurring virus, whereas the cell culture derived vaccines are time consuming and may not meet the demands of rapid global vaccination required to combat the present/future pandemic. Hemagglutinin (HA) based subunit vaccine for H1N1 requires the HA protein in glycosylated form, which is impossible with the commonly used bacterial expression platform. Additionally, bacterial derived protein requires extensive purification and refolding steps for vaccine applications. For these reasons an alternative heterologous system for rapid, easy and economical production of Hemagglutinin protein in its glycosylated form is required. The HA gene of novel H1N1 A/California/04/2009 was engineered for expression in Pichia pastoris as a soluble secreted protein. The full length HA- synthetic gene having α-secretory tag was integrated into P. pastoris genome through homologous recombination. The resultant Pichia clones having multiple copy integrants of the transgene expressed full length HA protein in the culture supernatant. The Recombinant yeast derived H1N1 HA protein elicited neutralising antibodies both in mice and rabbits. The sera from immunised animals also exhibited Hemagglutination Inhibition (HI) activity. Considering the safety, reliability and also economic potential of Pichia expression platform, our preliminary data indicates the feasibility of using this system as an alternative for large-scale production of recombinant influenza HA protein in the face of influenza pandemic threat

    Kruppel-like factor 7 overexpression suppresses hematopoietic stem and progenitor cell function

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    Increased expression of Kruppel-like factor 7 (KLF7) is an independent predictor of poor outcome in pediatric acute lymphoblastic leukemia. The contribution of KLF7 to hematopoiesis has not been previously described. Herein, we characterized the effect on murine hematopoiesis of the loss of KLF7 and enforced expression of KLF7. Long-term multilineage engraftment of Klf7(-/-) cells was comparable with control cells, and self-renewal, as assessed by serial transplantation, was not affected. Enforced expression of KLF7 results in a marked suppression of myeloid progenitor cell growth and a loss of short- and long-term repopulating activity. Interestingly, enforced expression of KLF7, although resulting in multilineage growth suppression that extended to hematopoietic stem cells and common lymphoid progenitors, spared T cells and enhanced the survival of early thymocytes. RNA expression profiling of KLF7-overexpressing hematopoietic progenitors identified several potential target genes mediating these effects. Notably, the known KLF7 target Cdkn1a (p21(Cip1/Waf1)) was not induced by KLF7, and loss of CDKN1A does not rescue the repopulating defect. These results suggest that KLF7 is not required for normal hematopoietic stem and progenitor function, but increased expression, as seen in a subset of lymphoid leukemia, inhibits myeloid cell proliferation and promotes early thymocyte survival. (Blood. 2012; 120(15): 2981-2989

    Homogenization of Optical Field in Nanocrystal-Embedded Perovskite Composites

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    Photonic upconversion of in-band light into shorter-wave-length light has been proposed as a protocol to overcome the Shockley-Queisser (SQ) limit of photovoltaics. Many research contributions haveattempted the incorporation of upconversion materials to realize thisstrategy. However, devising a real device with an efficiency exceeding theSQ limit still remains technically unreachable. To understand thisparadoxical question, herein we use a typical upconversion nanoparticle(UCNP) with halide perovskite as a platform to quantify the UCcontribution to the efficiency improvement. Our results show that theUC-induced photocurrent gain is negligible; nevertheless, the incorpo-ration of nanomaterials even without UC capability can still enhance thephotocurrent, which is related to a redistribution of the opticalfield andconsequently a homogenization of the opticalfield (HOF). This can lead toa reduced photocarrier loss and provide a noticeable photocurrent enhancement (ca. 7%), which explains the generalphotocurrent improvement in solar cells with nanomaterials

    CXCR2 and CXCR4 antagonistically regulate neutrophil trafficking from murine bone marrow

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    Neutrophils are a major component of the innate immune response. Their homeostasis is maintained, in part, by the regulated release of neutrophils from the bone marrow. Constitutive expression of the chemokine CXCL12 by bone marrow stromal cells provides a key retention signal for neutrophils in the bone marrow through activation of its receptor, CXCR4. Attenuation of CXCR4 signaling leads to entry of neutrophils into the circulation through unknown mechanisms. We investigated the role of CXCR2-binding ELR+ chemokines in neutrophil trafficking using mouse mixed bone marrow chimeras reconstituted with Cxcr2–/– and WT cells. In this context, neutrophils lacking CXCR2 were preferentially retained in the bone marrow, a phenotype resembling the congenital disorder myelokathexis, which is characterized by chronic neutropenia. Additionally, transient disruption of CXCR4 failed to mobilize Cxcr2–/– neutrophils. However, neutrophils lacking both CXCR2 and CXCR4 displayed constitutive mobilization, showing that CXCR4 plays a dominant role in neutrophil trafficking. With regard to CXCR2 ligands, bone marrow endothelial cells and osteoblasts constitutively expressed the ELR+ chemokines CXCL1 and CXCL2, and CXCL2 expression was induced in endothelial cells during G-CSF–induced neutrophil mobilization. Collectively, these data suggest that CXCR2 signaling is a second chemokine axis that interacts antagonistically with CXCR4 to regulate neutrophil release from the bone marrow
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