3,676 research outputs found

    Transient Expression of Tetrameric Recombinant Human Butyrylcholinesterase in Nicotiana benthamiana.

    Get PDF
    To optimize the expression, extraction and purification of plant-derived tetrameric recombinant human butyrylcholinesterase (prBChE), we describe the development and use of plant viral amplicon-based gene expression system; Tobacco Mosaic Virus (TMV) RNA-based overexpression vector (TRBO) to express enzymatically active FLAG-tagged plant made recombinant butyrylcholinesterase (rBChE) in Nicotiana benthamiana leaves using transient agroinfiltration. Two gene expression cassettes were designed to express the recombinant protein in either the ER or to the apoplastic compartment. Leaf homogenization was used to isolate ER-retained recombinant butyrylcholinesterase (prBChE-ER) while apoplast-targeted rBChE was isolated by either leaf homogenization (prBChE) or vacuum-extraction of apoplastic wash fluid (prBChE-AWF). rBChE from apoplast wash fluid had a higher specific activity but lower enzyme yield than leaf homogenate. To optimize the isolation and purification of total recombinant protein from leaf homogenates, an acidic extraction buffer was used. The acidic extraction buffer yielded >95% enzymatically active tetrameric rBChE as verified by Coomassie stained and native gel electrophoresis. Furthermore, when compared to human butyrylcholinesterase, the prBChE was found to be similar in terms of tetramerization and enzyme kinetics. The N-linked glycan profile of purified prBChE-ER was found to be mostly high mannose structures while the N-linked glycans on prBChE-AWF were primarily complex. The glycan profile of the prBChE leaf homogenates showed a mixture of high mannose, complex and paucimannose type N-glycans. These findings demonstrate the ability of plants to produce rBChE that is enzymatically active and whose oligomeric state is comparable to mammalian butyrylcholinesterase. The process of plant made rBChE tetramerization and strategies for improving its pharmacokinetics properties are also discussed

    Vascular Proteomics Reveal Novel Proteins Involved in SMC Phenotypic Change: OLR1 as a SMC Receptor Regulating Proliferation and Inflammatory Response

    Get PDF
    Neointimal hyperplasia of vascular smooth muscle cells (VSMC) plays a critical role in atherosclerotic plaque formation and in-stent restenosis, but the underlying mechanisms are still incompletely understood. We performed a proteomics study to identify novel signaling molecules organizing the VSMC hyperplasia. The differential proteomics analysis in a balloon- induced injury model of rat carotid artery revealed that the expressions of 44 proteins are changed within 3 days post injury. The combination of cellular function assays and a protein network analysis further demonstrated that 27 out of 44 proteins constitute key signaling networks orchestrating the phenotypic change of VSMC from contractile to epithelial-like synthetic. Among the list of proteins, the in vivo validation specifically revealed that six proteins (Rab 15, ITR, OLR1, PDH beta, PTP epsilon) are positive regulators for VSMC hyperplasia. In particular, the OLR1 played dual roles in the VSMC hyperplasia by directly mediating oxidized LDL-induced monocyte adhesion via NF-kappa B activation and by assisting the PDGF-induced proliferation/migration. Importantly, OLR1 and PDGFR beta were associated in close proximity in the plasma membrane. Thus, this study elicits the protein network organizing the phenotypic change of VSMC in the vascular injury diseases such as atherosclerosis and discovers OLR1 as a novel molecular link between the proliferative and inflammatory responses of VSMCs.1133Ysciescopu

    Noninvasive imaging of radiolabeled exosome-mimetic nanovesicle using Tc-99m-HMPAO

    Get PDF
    Exosomes known as nano-sized extracellular vesicles attracted recent interests due to their potential usefulness in drug delivery. Amid remarkable advances in biomedical applications of exosomes, it is crucial to understand in vivo distribution and behavior of exosomes. Here, we developed a simple method for radiolabeling of macrophage-derived exosome-mimetic nanovesicles (ENVs) with Tc-99m-HMPAO under physiologic conditions and monitored in vivo distribution of Tc-99m-HMPAO-ENVs using SPECT/CT in living mice. ENVs were produced from the mouse RAW264.7 macrophage cell line and labeled with Tc-99m-HMPAO for 1 hr incubation, followed by removal of free Tc-99m-HMPAO. SPECT/CT images were serially acquired after intravenous injection to BALB/c mouse. When ENVs were labeled with Tc-99m-HMPAO, the radiochemical purity of Tc-99m-HMPAO-ENVs was higher than 90% and the expression of exosome specific protein (CD63) did not change in Tc-99m-HMPAO-ENVs. Tc-99m-HMPAOENVs showed high serum stability (90%) which was similar to that in phosphate buffered saline until 5 hr. SPECT/CT images of the mice injected with Tc-99m-HMPAO-ENVs exhibited higher uptake in liver and no uptake in brain, whereas mice injected with Tc-99m-HMPAO showed high brain uptake until 5 hr. Our noninvasive imaging of radiolabeled-ENVs promises better understanding of the in vivo behavior of exosomes for upcoming biomedical application.114327Ysciescopu

    A List Scheduling Heuristic with New Node Priorities and Critical Child Technique for Task Scheduling with Communication Contention

    Get PDF
    Task scheduling is becoming an important aspect for parallel programming of modern embedded systems. In this chapter, the application to be scheduled is modeled as a Directed Acyclic Graph (DAG), and the architecture targets parallel embedded systems composed of multiple processors interconnected by buses and/or switches. This chapter presents new list scheduling heuristics with communication contention. Furthermore, we define new node priorities (top level and bottom level) to sort nodes, and propose an advanced technique named critical child to select a processor to execute a node. Experimental results show that the proposed method is effective to reduce the schedule length, and the runtime performance is greatly improved in the cases of medium and high communication. Since the communication cost is increasing from medium to high in modern applications like digital communication and video compression, the proposed method is well-adapted for scheduling these applications over parallel embedded systems

    Mid-infrared plasmons in scaled graphene nanostructures

    Full text link
    Plasmonics takes advantage of the collective response of electrons to electromagnetic waves, enabling dramatic scaling of optical devices beyond the diffraction limit. Here, we demonstrate the mid-infrared (4 to 15 microns) plasmons in deeply scaled graphene nanostructures down to 50 nm, more than 100 times smaller than the on-resonance light wavelength in free space. We reveal, for the first time, the crucial damping channels of graphene plasmons via its intrinsic optical phonons and scattering from the edges. A plasmon lifetime of 20 femto-seconds and smaller is observed, when damping through the emission of an optical phonon is allowed. Furthermore, the surface polar phonons in SiO2 substrate underneath the graphene nanostructures lead to a significantly modified plasmon dispersion and damping, in contrast to a non-polar diamond-like-carbon (DLC) substrate. Much reduced damping is realized when the plasmon resonance frequencies are close to the polar phonon frequencies. Our study paves the way for applications of graphene in plasmonic waveguides, modulators and detectors in an unprecedentedly broad wavelength range from sub-terahertz to mid-infrared.Comment: submitte

    Dry-air-stable lithium silicide-lithium oxide core-shell nanoparticles as high-capacity prelithiation reagents

    Get PDF
    Rapid progress has been made in realizing battery electrode materials with high capacity and long-term cyclability in the past decade. However, low first-cycle Coulombic efficiency as a result of the formation of a solid electrolyte interphase and Li trapping at the anodes, remains unresolved. Here we report LixSi-Li2O core-shell nanoparticles as an excellent prelithiation reagent with high specific capacity to compensate the first-cycle capacity loss. These nanoparticles are produced via a one-step thermal alloying process. LixSi-Li2O core-shell nanoparticles are processible in a slurry and exhibit high capacity under dry-air conditions with the protection of a Li2O passivation shell, indicating that these nanoparticles are potentially compatible with industrial battery fabrication processes. Both Si and graphite anodes are successfully prelithiated with these nanoparticles to achieve high first-cycle Coulombic efficiencies of 94% to 4100%. The LixSi-Li2O core-shell nanoparticles enable the practical implementation of high-performance electrode materials in lithium-ion batteries.open6
    corecore