30 research outputs found

    Solid-State Nuclear Magnetic Resonance of Protein Characterization at Fast Magic Angle Spinning

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    In the thesis studies, three related projects using SSNMR were carried out on proteins and peptides in solids. In the first project, we implemented high-resolution SSNMR to inspect the secondary structural formation of peptides in the course of SPPS to gain structural insight into the cause of drastically reduced synthesis yield for a long peptide sequence. In the second project, a novel SSNMR approach was established to assist the side-chain signal assignment of trace amount proteins by enhancing both sensitivity and resolution. In the third project, we established a novel SSNMR spectral editing method, termed HIGHLIGHT, to extremely simplify the SSNMR spectra under ultra-fast MAS condition

    Revealing Protein Structures in Solid-Phase Peptide Synthesis by <sup>13</sup>C Solid-State NMR: Evidence of Excessive Misfolding for Alzheimer’s β

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    Solid-phase peptide synthesis (SPPS) is a widely used technique in biology and chemistry. However, the synthesis yield in SPPS often drops drastically for longer amino acid sequences, presumably because of the occurrence of incomplete coupling reactions. The underlying cause for this problem is hypothesized to be a sequence-dependent propensity to form secondary structures through protein aggregation. However, few methods are available to study the site-specific structure of proteins or long peptides that are anchored to the solid support used in SPPS. This study presents a novel solid-state NMR (SSNMR) approach to examine protein structure in the course of SPPS. As a useful benchmark, we describe the site-specific SSNMR structural characterization of the 40-residue Alzheimer’s β-amyloid (Aβ) peptide during SPPS. Our 2D <sup>13</sup>C/<sup>13</sup>C correlation SSNMR data on Aβ(1–40) bound to a resin support demonstrated that Aβ underwent excessive misfolding into a highly ordered β-strand structure across the entire amino acid sequence during SPPS. This approach is likely to be applicable to a wide range of peptides/proteins bound to the solid support that are synthesized through SPPS

    Additional file 1: of Aspirin promotes bone marrow mesenchymal stem cell-based calvarial bone regeneration in mini swine

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    Concentration of aspirin and salicylic acid in the gelatin sponge at different time points normalized to the weight of gelatin sponge. Aspirin or salicylic acid could almost not be detected after 3 h. (JPEG 491 kb

    MicroRNAome and Expression Profile of Developing Tooth Germ in Miniature Pigs

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    <div><p>MicroRNAs (miRNAs) play important roles in the regulation of rodent tooth development, but little is known about their role in tooth development in large mammals. We identified 637 unique miRNA sequences in a large-scale screen for miRNA expression profiles in the developing lower deciduous molars of miniature pigs (<em>Sus scrofa</em>) using Illumina Solexa deep sequencing. These candidate miRNAs and another 105 known <em>Sus scrofa</em> miRNAs were included in the custom-designed microarray and used to analyze the miRNA expression profile in the bud, cap, early bell, and late bell stages of tooth development. Microarray analysis revealed 166 transcripts that were differentially expressed in the four stages. Bioinformatic analysis identified 18 key miRNAs, including let-7f, miR-128, miR-200b, and miR-200c, that might play key roles in tooth development. Taken together, our results not only identified the specific microRNAome and expression profile in developing lower deciduous molars of the miniature pig, but they also provided useful information for investigating the molecular mechanism of tooth development in the miniature pig.</p> </div

    Analysis of sequencing data.

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    <p>To obtain mappable sequences from raw sequencing data, we used a series of digital filters to remove various unmappable sequencing reads. (A) Unique families of sequences were generated by sorting raw sequencing reads. “Impure” sequences were then removed by sample preparation, sequencing chemistry and processes, and the optical digital resolution of the sequencer detector. Unique sequences were pulled from selected databases, including mRNA, rRNA, tRNA, snRNA, snoRNA, and Repbase databases. (B) (<i>i</i>) A length filter was used to retain unique sequences of 16–26 nt. (<i>ii</i>) Sequences with copy numbers greater than the predefined cut-off number (default = 3) were also retained. (C) After masking the adaptor sequences and removing contaminated reads, the 92.65% mappable clean reads were processed for advanced analysis. (D) The unique mapped sequences were grouped as “unique sequences mapped to selected species pre-miRNAs in miRbase, and further mapped to pig genome and EST,” and divided into six groups.</p

    Preparation of landscape gardening soil using undersized fraction from aged MSW by EDTA or citric acid coupled with humic acid: Effect assessment, properties, and optimization

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    Undersized fraction from aged municipal solid waste (UFAMSW), as a kind of soil-like material, has been proved effective in providing a large amount of organic matter and nutrients for soil and plants. The characteristics and effectiveness of heavy metal pollution removal in UFAMSW attracted tremendous research interest from scientists recently. In this study, the heavy metal removal efficiencies and bioavailability of washing on contaminated UFAMSW were evaluated with three washing reagents including ethylene diamine tetra acetic acid (EDTA), citric acid (CA), and humic acid (HA). The effects of chelating agent concentration, pH, and washing time on metal removal were investigated and response surface methodology (RSM) was employed to optimize the washing conditions. The results indicated that the removal efficiencies of Cu, Zn, and Mn could be 53.68%, 52.12%, and 30.63% by EDTA/HA washing and 42.36%, 39.67% and 28.49% by CA/HA washing, respectively. The European Community Bureau of Reference (BCR) sequential extraction was applied to analyze the fraction change of heavy metals in UFAMSW before and after washing, and it was found that chelating agent combined with HA could contribute to the removal of the exchangeable fraction. Physical and chemical properties of UFAMSW were improved to some extent after washing with mixed HA and chelating agent and could achieve the quality standard of landscape gardening soil. Accordingly, the mixture of HA and other chelating agents could be a promising washing process for preparation of landscape gardening soil using UFAMSW. Implications: Our manuscript studies the removal of heavy metals from the contaminated undersized fraction from aged municipal solid waste (UFAMSW). UFAMSW, as a kind of soil-like material, has been proved effective in providing a large amount of organic matter and nutrients for soil and plants however often limited by heavy metal pollution. The UFAMSW used in this experiment was collected after the excavation and screening-sorting of aged refuse from Changshankou Domestic Waste Sanitary Landfill in Wuhan City, Hubei Province, Southern China. This study investigated the effects of EDTA, CA, HA, mixed EDTA/HA, and mixed CA/HA washing on heavy metal removal (Cu, Zn, and Mn), bioavailability of residual heavy metal and properties. The effects of chelating agent concentration, pH, and washing time on metal removal were investigated and then response surface methodology was employed to optimize the washing conditions. The results showed that washing by CA/HA and EDTA/HA, had a higher removal efficiency of heavy metals (Cu, Zn, and Mn) in UFAMSW compared to single HA. Meanwhile, HA has a higher removal for exchangeable fraction of heavy metals, the exchangeable concentration of Cu, Zn, and Mn in CA/HA and EDTA/HA washed UFAMSW were lower compared with UFAMSW washed by single CA and EDTA. Thus, mixing HA with EDTA or CA makes a less risk to environmental and the removal efficiency is acceptable. Additionally, CA/HA and EDTA/HA washing tend to improve soil physicochemical properties and soil fertility. Thus, mixing HA with different washing agent are potential methods for preparation of landscape gardening soil using UFAMSW.</p
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