22 research outputs found

    An Efficient and Faithful in Vitro Replication System for Threose Nucleic Acid

    No full text
    The emerging field of synthetic genetics provides an opportunity to explore the structural and functional properties of synthetic genetic polymers by in vitro selection. Limiting this process, however, is the availability of enzymes that allow for the synthesis and propagation of genetic information present in unnatural nucleic acid sequences. Here, we report the development of a transcription and reverse-transcription system that can replicate unnatural genetic polymers composed of threose nucleic acids (TNA). TNA is a potential progenitor of RNA in which the natural ribose sugar found in RNA has been replaced with an unnatural threose sugar. Using commercial polymerases that recognize TNA, we demonstrate that an unbiased three-letter and two different biased four-letter genetic alphabets replicate in vitro with high efficiency and high overall fidelity. We validated the replication system by performing one cycle of transcription, selection, reverse transcription, and amplification on a library of 10<sup>14</sup> DNA templates and observed ∼380-fold enrichment after one round of selection for a biotinylated template. We further show that TNA polymers are stable to enzymes that degrade DNA and RNA. These results provide the methodology needed to evolve biologically stable aptamers and enzymes for exobiology and molecular medicine

    Rac1 regulates M1 protein-induced lung damage.

    No full text
    <p>Representative haematoxylin & eosin sections of lung. Sham animals were treated with PBS only. Separate mice were pretreated with vehicle (PBS) and 0.5 or 5 mg/kg of the Rac1 inhibitor NSC23766 10 min prior to M1 protein administration. Samples were harvested 4 h after M1 protein challenge. Scale bar indicates 100 µm. Histology score of lung injury. Data represents mean ± SEM, *<i>P</i> < 0.05 <i>vs.</i> Sham and <b><sup>#</sup></b><i>P</i> < 0.05 <i>vs.</i> Vehicle+M1 protein, <i>n = </i>5.</p

    Macrophages (RAW264.7) and endothelial cells (eEND2) were co-incubated with 10 µM Rac-1 inhibitor NSC23766 1 h prior to M1 protein (0.5 µg/ml) stimulation.

    No full text
    <p>ELISA was used to quantify the levels of CXCL2 in the supernatants 4 h after M1 protein challenge. Data represents mean ± SEM, *<i>P</i> < 0.05 <i>vs.</i> Sham and <sup>#</sup><i>P</i> < 0.05 <i>vs.</i> Vehicle+M1 protein, <i>n = </i>5.</p

    M1 protein-induced Mac-1 expression on neutrophils <i>in vivo</i>.

    No full text
    <p>Mac-1 expression on neutrophils in vehicle (PBS) or NSC23766 (0.5 or 5 mg/kg), treated animals 4 h after M1 protein injection. Fluorescence intensity is shown on the x-axis and cell counts on the y-axis. Data represents mean ± SEM, <sup>*</sup><i>P</i> < 0.05 <i>vs.</i> Sham and <sup>#</sup><i>P</i> < 0.05 <i>vs.</i> Vehicle+M1 protein, <i>n = </i>5.</p

    Systemic leukocyte differential counts.

    No full text
    <p>Blood was collected from sham animals receiving PBS intravenously only as well as mice were pretreated i.p. with vehicle (PBS) or NSC23766 10 min prior to M1 protein challenge for 4 h. Cells were identified as monomorphonuclear leukocytes (MNL) and polymorphonuclear leukocytes (PMNL). Data represents mean ± SEM, 10<sup>6</sup> cells/ml and <i>n = </i>5.</p>*<p><i>P</i> < 0.05 <i>vs.</i> Sham and <sup>#</sup><i>P</i> < 0.05 <i>vs.</i> Vehicle+M1 protein, <i>n = </i>5.</p

    Rac1 regulates M1 protein-induced neutrophil infiltration in the lung.

    No full text
    <p>MPO levels and number of BALF neutrophils in the lung. Animals were treated with the Rac1 inhibitor NSC23766 (0.5 or 5 mg/kg) or vehicle (PBS) 10 min prior to M1 protein injection. Samples were harvested 4 h after M1 protein challenge. Mice treated with PBS served as sham animals. Data represents mean ± SEM, *<i>P</i> < 0.05 <i>vs.</i> Sham and <b><sup>#</sup></b><i>P</i> < 0.05 <i>vs.</i> Vehicle+M1 protein, <i>n = </i>5.</p

    Rac1 regulates M1 protein-induced edema formation in the lung.

    No full text
    <p>Mice were treated with the Rac1 inhibitor NSC23766 (0.5 or 5 mg/kg) or vehicle (PBS) 10 min prior to M1 protein injection. Mice treated with PBS served as sham animals. Samples were harvested 4 h after M1 protein challenge. Data represents mean ± SEM, *<i>P</i> < 0.05 <i>vs.</i> Sham and <b><sup>#</sup></b><i>P</i> < 0.05 <i>vs.</i> Vehicle+M1 protein, <i>n = </i>5.</p

    Rac1 regulates M1 protein-induced gene expression of CXC chemokines in alveolar macrophages.

    No full text
    <p>CXCL1 and CXCL2 in alveolar macrophages 30 min after M1 protein injection. Levels of CXCL1 and CXCL2 mRNA were normalized to mRNA levels of β-actin. Data represents mean ± SEM, *<i>P</i> < 0.05 <i>vs.</i> Sham and <b><sup>#</sup></b><i>P</i> < 0.05 <i>vs.</i> Vehicle+M1 protein, <i>n = </i>5.</p

    Simultaneous Purification and Perforation of Low-Grade Si Sources for Lithium-Ion Battery Anode

    No full text
    Silicon is regarded as one of the most promising candidates for lithium-ion battery anodes because of its abundance and high theoretical capacity. Various silicon nanostructures have been heavily investigated to improve electrochemical performance by addressing issues related to structure fracture and unstable solid–electrolyte interphase (SEI). However, to further enable widespread applications, scalable and cost-effective processes need to be developed to produce these nanostructures at large quantity with finely controlled structures and morphologies. In this study, we develop a scalable and low cost process to produce porous silicon directly from low grade silicon through ball-milling and modified metal-assisted chemical etching. The morphology of porous silicon can be drastically changed from porous-network to nanowire-array by adjusting the component in reaction solutions. Meanwhile, this perforation process can also effectively remove the impurities and, therefore, increase Si purity (up to 99.4%) significantly from low-grade and low-cost ferrosilicon (purity of 83.4%) sources. The electrochemical examinations indicate that these porous silicon structures with carbon treatment can deliver a stable capacity of 1287 mAh g<sup>–1</sup> over 100 cycles at a current density of 2 A g<sup>–1</sup>. This type of purified porous silicon with finely controlled morphology, produced by a scalable and cost-effective fabrication process, can also serve as promising candidates for many other energy applications, such as thermoelectrics and solar energy conversion devices
    corecore