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- Gao, Jia, et al.
(författare)
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Chemoenzymatic Synthesis of Glycopeptides Bearing Galactose-Xylose Disaccharide from the Proteoglycan Linkage Region
- 2021
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 23:5, s. 1738-1741
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Tidskriftsartikel (refereegranskat)abstract
- Proteoglycans have important biological activities. To improve the overall synthetic efficiency, a new chemoenzymatic route has been established for the proteoglycan linkage region bearing a galactose-xylose disaccharide. The xylosylated glycopeptides were synthesized via solid phase synthesis, which was followed by the addition of the galactose unit by the galactosyl transferase β4GalT7. This work leads to a better understanding of the acceptor preference of β4GalT7 and opens the door for expeditious synthesis of the proteoglycan linkage region.
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| 2. |
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| 3. |
- Li, Yiyin, et al.
(författare)
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Pollen production estimates (PPEs) and fall speeds for major tree taxa and relevant source areas of pollen (RSAP) in Changbai Mountain, northeastern China
- 2015
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Ingår i: Review of Palaeobotany and Palynology. - 0034-6667. ; 216, s. 92-100
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Tidskriftsartikel (refereegranskat)abstract
- For model-based quantitative reconstructions of past vegetation cover on the scale of landscapes, pollen productivity estimates (PPEs) are key input parameters. In this study, we employed a random sampling strategy to collect moss polsters at 20 sites in Changbai Mountain, northeastern China. A detailed vegetation survey within 1000-m radius around each sampling point was carried out and digitized vegetation maps were used for, vegetation data compilation. A forest map at the scale of 1:25,000 was used to extract information about vegetation for the area between 1000 and 5000 m from each sampling point. Using the ERV (Extended R-Value) model, pollen productivity was estimated for Larix, Pinus, Juglans, Ulmus, Tilia, Betula and Fraxinus relative to Quercus. Estimates of pollen fall speeds for the eight taxa as well as the relevant source area of pollen (RSAP) were also obtained. Three different ERV sub-models were tested against the data. The sub-model 3 produced the best goodness of fit and the PPE values calculated with this sub-model show that BMA (5.04), Pinus (3.11), Juglans (1.94) and Ulmus (1.40) are high pollen producers with higher PPEs than Quercus while Fraxinus (0.76), Larix (0.30), Tilia (0.16) are low pollen producers compared to Quercus. The high pollen producers are all anemophilous species, while low pollen producing plants include both entomophilous, such as Fraxinus, Tilia and anemophilous species such as Larix. The estimated RSAP for the eight tree pollen taxa is about 2000-2500 m. (C) 2015 Elsevier B.V. All rights reserved.
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| 4. |
- Wang, Jingxin, et al.
(författare)
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Label-free quantitative comparison of cerebrospinal fluid glycoproteins and endogenous peptides in subjects with Alzheimer's disease, mild cognitive impairment, and healthy individuals.
- 2016
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Ingår i: Proteomics. Clinical applications. - : Wiley. - 1862-8354 .- 1862-8346. ; 10:12, s. 1225-1241
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Tidskriftsartikel (refereegranskat)abstract
- The goal of this study is to investigate putative molecular dynamic changes in cerebrospinal fluids (CSFs) collected from individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD) as compared to healthy controls.The CSF samples from 12 subjects comprised of four cognitively normal individuals and eight patients with MCI and AD, respectively. Two aliquots of each CSF samples (total 1 mL) of each participant are used for this study. Endogenous peptide separations are performed using 10 000 molecular weight cut-off filters followed by LC-MS/MS identification and quantitation while lectin-enrichment chromatography is used to enrich glycoproteins in CSF followed by trypsin digestion and subsequent LC-MS/MS for shotgun identification and label-free quantitation.Using an optimized submicrogram peptide separation with molecular weight cut-off filtration and an in house-constructed database, 645 peptides are identified. Glycoproteins are enriched by lectin affinity chromatography, resulting in 795 identified proteins. The discovery and alterations of proSAAS-derived peptides and transthyretin are described and their roles in AD are discussed.Comprehensive identification of endogenous CSF peptidome is achieved. Fifteen proteins are found to be differentially expressed among the three groups. The dynamic changes of transthyretin are reported for the first time.
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