| 1. |
- Shen, Qian, et al.
(författare)
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The Genome of Artemisia annua Provides Insight into the Evolution of Asteraceae Family and Artemisinin Biosynthesis
- 2018
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Ingår i: Molecular Plant. - : Cell Press. - 1674-2052 .- 1752-9867. ; 11:6, s. 776-788
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Tidskriftsartikel (refereegranskat)abstract
- Artemisia annua, commonly known as sweet wormwood or Qinghao, is a shrub native to China and has long been used for medicinal purposes. A. annua is now cultivated globally as the only natural source of a potent anti-malarial compound, artemisinin. Here, we report a high-quality draft assembly of the 1.74-gigabase genome of A. annua, which is highly heterozygous, rich in repetitive sequences, and contains 63 226 protein-coding genes, one of the largest numbers among the sequenced plant species. We found that, as one of a few sequenced genomes in the Asteraceae, the A. annua genome contains a large number of genes specific to this large angiosperm clade. Notably, the expansion and functional diversification of genes encoding enzymes involved in terpene biosynthesis are consistent with the evolution of the artemisinin biosynthetic pathway. We further revealed by transcriptome profiling that A. annua has evolved the sophisticated transcriptional regulatory networks underlying artemisinin biosynthesis. Based on comprehensive genomic and transcriptomic analyses we generated transgenic A. annua lines producing high levels of artemisinin, which are now ready for large-scale production and thereby will help meet the challenge of increasing global demand of artemisinin.
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| 2. |
- Zhang, Yan, et al.
(författare)
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Dynamic covalent kinetic resolution
- 2020
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Ingår i: Catalysis reviews. Science and engineering. - : Taylor & Francis Group. - 0161-4940 .- 1520-5703. ; 62:1, s. 66-95
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Tidskriftsartikel (refereegranskat)abstract
- Implemented with the highly efficient concept of Dynamic Kinetic Resolution (DKR), dynamic covalent chemistry can be a useful strategy for the synthesis of enantioenriched compounds. This gives rise to dynamic covalent kinetic resolution (DCKR), a subset of DKR that over the last decades has emerged as increasingly fruitful, with many applications in asymmetric synthesis and catalysis. All DKR protocols are composed of two important parts: substrate racemization and asymmetric transformation, which can lead to yields of >50% with good enantiomeric excesses (ee) of the products. In DCKR systems, by utilizing reversible covalent reactions as the racemization strategy, the substrate enantiomers can be easily interconverted without the presence of any racemase or transition metal catalyst. Enzymes or other chiral catalysts can then be adopted for the resolution step, leading to products with high enantiopurities. This tutorial review focuses on the development of DCKR systems, based on different reversible reactions, and their applications in asymmetric synthesis.
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| 3. |
- Cui, Liang, et al.
(författare)
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Four additional natural 7-deazaguanine derivatives in phages and how to make them
- 2023
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 51:17, s. 9214-9226
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Tidskriftsartikel (refereegranskat)abstract
- Bacteriophages and bacteria are engaged in a constant arms race, continually evolving new molecular tools to survive one another. To protect their genomic DNA from restriction enzymes, the most common bacterial defence systems, double-stranded DNA phages have evolved complex modifications that affect all four bases. This study focuses on modifications at position 7 of guanines. Eight derivatives of 7-deazaguanines were identified, including four previously unknown ones: 2 & PRIME;-deoxy-7-(methylamino)methyl-7-deazaguanine (mdPreQ(1)), 2 & PRIME;-deoxy-7-(formylamino)methyl-7-deazaguanine (fdPreQ(1)), 2 & PRIME;-deoxy-7-deazaguanine (dDG) and 2 & PRIME;-deoxy-7-carboxy-7-deazaguanine (dCDG). These modifications are inserted in DNA by a guanine transglycosylase named DpdA. Three subfamilies of DpdA had been previously characterized: bDpdA, DpdA1, and DpdA2. Two additional subfamilies were identified in this work: DpdA3, which allows for complete replacement of the guanines, and DpdA4, which is specific to archaeal viruses. Transglycosylases have now been identified in all phages and viruses carrying 7-deazaguanine modifications, indicating that the insertion of these modifications is a post-replication event. Three enzymes were predicted to be involved in the biosynthesis of these newly identified DNA modifications: 7-carboxy-7-deazaguanine decarboxylase (DpdL), dPreQ(1) formyltransferase (DpdN) and dPreQ(1) methyltransferase (DpdM), which was experimentally validated and harbors a unique fold not previously observed for nucleic acid methylases.
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| 4. |
- Hedi, Wen, et al.
(författare)
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γ-Cyclodextrin-BSA for nano-encapsulation of hydrophobic substance
- 2021
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Ingår i: Food Bioscience. - : Elsevier. - 2212-4292 .- 2212-4306. ; 41
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Tidskriftsartikel (refereegranskat)abstract
- Self-aggregation and the hemolytic effect limit the application of gamma-cyclodextrin (gamma-CD) in bioactive molecular delivery systems. In this study, gamma-CD was modified by grafting onto bovine serum albumin protein (BSA), with epichlorohydrin (ECH) acting as the cross-linking agent. The effects of BSA concentration, reaction temperature, pH and time on the grafting rate were studied, and the gamma-CD-BSA complex with a grafting rate of 99.5 +/- 0.1% +/- 0.06)% was achieved. The complex was confirmed using H-1 NMR and FT-IR spectra. Compared with gamma-CD, the hemolytic effect and self-aggregation of gamma-CD-BSA were significantly reduced, and the encapsulation efficiency of curcumin was increased by 10.8%. The results of scanning electron microscopy showed that both gamma-CD and gamma-CDBSA nanoparticles were formed and the structure of the gamma-CD-BSA complex was more uniform. The pH stability and salt stability of gamma-CD-BSA were higher than gamma-CD. The release rate of gamma-CD-BSA was 15.2 +/- 0.2% after 2 h at pH 1.2, and 57 +/- 1% after 4 h at pH 7.2. The gamma-CD-BSA nanoparticles could protect curcumin in acidic environments and release it in neutral environments. The results suggested a promising wall material for delivery of hydrophobic substances.
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| 5. |
- Karalius, Antanas, et al.
(författare)
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Formation and Out-of-Equilibrium, High/Low State Switching of a Nitroaldol Dynamer in Neutral Aqueous Media
- 2020
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlag. - 1433-7851 .- 1521-3773. ; 59:9, s. 3434-3438
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Tidskriftsartikel (refereegranskat)abstract
- The nitroaldol reaction is demonstrated as an efficient dynamic covalent reaction in phosphate buffers at neutral pH. Rapid equilibration was recorded with pyridine-based aldehydes, and dynamic oligomerization could be achieved, leading to nitroaldol dynamers of up to 17 repeating units. The dynamers were applied in a coherent stimuli-responsive molecular system in which larger dynamers transiently existed out-of-equilibrium in a neutral aqueous system rich in formaldehyde, controlled by nitromethane.
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| 6. |
- Xie, Sheng, et al.
(författare)
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A versatile catalyst-free perfluoroaryl azide-aldehyde-amine conjugation reaction
- 2019
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Ingår i: Materials Chemistry Frontiers. - : Royal Society of Chemistry. - 2052-1537. ; 3:2, s. 251-256
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Tidskriftsartikel (refereegranskat)abstract
- In a tri-component reaction, an electrophilically-activated perfluoroaryl azide, an enolizable aldehyde and an amine react readily at room temperature without any catalysts in solvents including aqueous conditions to yield a stable amidine conjugate. The versatility of this reaction is demonstrated in the conjugation of an amino acid without prior protection of the carboxyl group, and in the synthesis of antibiotic-nanoparticle conjugates.
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| 7. |
- Zhang, Yan, et al.
(författare)
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Dynamic covalent polymers for biomedical applications
- 2020
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Ingår i: Materials Chemistry Frontiers. - : Royal Society of Chemistry. - 2052-1537. ; 4:2, s. 489-506
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Forskningsöversikt (refereegranskat)abstract
- The rapid development of supramolecular polymer chemistry and constitutional dynamic chemistry over the last decades has made tremendous impact on the emergence of dynamic covalent polymers. These materials are formed through reversible covalent bonds, endowing them with adaptive and responsive features that have resulted in high interest throughout the community. Owing to their intriguing properties, such as self-healing, shape-memory effects, recyclability, degradability, stimuli-responsiveness, etc., the materials have found multiple uses in a wide range of areas. Of special interest is their increasing use for biomedical applications, and many examples have been demonstrated in recent years. These materials have thus been used for the recognition and sensing of biologically active compounds, for the modulation of enzyme activity, for gene delivery, and as materials for cell culture, delivery, and wound-dressing. In this review, some of these endeavors are discussed, highlighting the many advantages and unique properties of dynamic covalent polymers for use in biology and biomedicine.
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| 8. |
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| 9. |
- Zhang, Yan, et al.
(författare)
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Surface-Directed Selection of Dynamic Constitutional Frameworks as an Optimized Microenvironment for Controlled Enzyme Activation
- 2020
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 10:2, s. 1423-1427
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic constitutional frameworks composed of cross-linked networks of imine-exchanging components have been generated and applied to the establishment of optimal microenvironments for carbonic anhydrase (CA) in aqueous solution., In response to the dynamic recomposition process, the enzyme showed distinct differential preferences for interchanging and incorporation of the amine functionalities, which were furthermore in good correlation with their inverse activation effects of CA. The results demonstrated surface-directed selection of the enzyme environment, where amines with lower enzyme-directed incorporation ratio possess higher activation effects, leading to a strategy of self-optimization of the enzyme microenvironment for better catalytic performances.
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