2-(2-Phenylethyl)chromones (PECs) are the principal constituents contributing to the distinctive fragrance of agarwood. How PECs are biosynthesized is currently unknown. In this work, we describe a ...diarylpentanoid-producing polyketide synthase (PECPS) identified from Aquilaria sinensis. Through biotransformation experiments using fluorine-labeled substrate, transient expression of PECPS in Nicotiana benthamiana, and knockdown of PECPS expression in A. sinensis calli, we demonstrate that the C
-C
-C
scaffold of diarylpentanoid is the common precursor of PECs, and PECPS plays a crucial role in PECs biosynthesis. Crystal structure (1.98 Å) analyses and site-directed mutagenesis reveal that, due to its small active site cavity (247 Å
), PECPS employs a one-pot formation mechanism including a "diketide-CoA intermediate-released" step for the formation of the C
-C
-C
scaffold. The identification of PECPS, the pivotal enzyme of PECs biosynthesis, provides insight into not only the feasibility of overproduction of pharmaceutically important PECs using metabolic engineering approaches, but also further exploration of how agarwood is formed.
Platinum‐catalyzed formal 5+2 and 4+2 annulations of isoxazoles with heterosubstituted alkynes enabled the atom‐economical synthesis of valuable 1,3‐oxazepines and 2,5‐dihydropyridines, respectively. ...Importantly, this Pt catalysis not only led to unique reactivity dramatically divergent from that observed under Au catalysis, but also proceeded via unprecedented α‐imino platinum carbene intermediates.
Gold's deviant relative: Platinum‐catalyzed formal 5+2 and 4+2 annulations of isoxazoles and heterosubstituted alkynes provided valuable 1,3‐oxazepines and 2,5‐dihydropyridines (see scheme). This reactivity deviates dramatically from that observed under gold catalysis and involves the generation of an α‐imino platinum carbene. A computational study provided evidence for the proposed mechanism of this unusual tandem sequence.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A highly enantioselective NiH‐catalyzed hydrocyclization of alkynones with unparalleled anti‐ and endocyclic selectivities is described. The choice of the precatalysts has significant influence in ...tuning the regio‐ and enantioselectivity. Using Ni(OTs)2/Phox as a precatalyst and (EtO)2MeSiH as a hydride source, an array of enantioenriched O‐, N‐, and S‐containing heterocyclic tertiary allylic alcohols are obtained in 24–81 % yields with 80:20–99:1 er. Mechanistic investigations and synthetic application are also carried out. This study represents an efficient access to a set of allylic alcohols that are unable to access by the state‐of‐the‐art coupling reactions.
An unprecedented NiH‐catalyzed enantio‐, regio‐, and anti‐selective intramolecular coupling of alkynones to construct O‐, N‐, S‐containing endocyclic allylic alcohols was developed. The choice of metal precursors plays a key role in tuning the regio‐ and enantio‐selectivity. This study offers a new anti‐hydrocyclization mode for enantioselective hydrofunctionalization of alkynes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Snakes have numerous features distinctive from other tetrapods and a rich history of genome evolution that is still obscure. Here, we report the high-quality genome of the five-pacer viper, ...Deinagkistrodon acutus, and comparative analyses with other representative snake and lizard genomes. We map the evolutionary trajectories of transposable elements (TEs), developmental genes and sex chromosomes onto the snake phylogeny. TEs exhibit dynamic lineage-specific expansion, and many viper TEs show brain-specific gene expression along with their nearby genes. We detect signatures of adaptive evolution in olfactory, venom and thermal-sensing genes and also functional degeneration of genes associated with vision and hearing. Lineage-specific relaxation of functional constraints on respective Hox and Tbx limb-patterning genes supports fossil evidence for a successive loss of forelimbs then hindlimbs during snake evolution. Finally, we infer that the ZW sex chromosome pair had undergone at least three recombination suppression events in the ancestor of advanced snakes. These results altogether forge a framework for our deep understanding into snakes' history of molecular evolution.
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•Achievements on 17 representative types of IR–NLO chalcogenides based on the chemical substitution strategy are overviewed.•The interrelationship of “chemical composition-NCS ...structure-NLO property” is studied and summarized systematically.•Several useful conclusions and future considerations have been provided.
Infrared nonlinear optical (IR–NLO) materials are crucial for obtaining the solid-state lasers in the spectral range of 2–20 μm, which have a broad range of applications, such as signal communication, microscopy, and data processing. Yet, the considerable challenge is how to obtain a strictly structural non-centrosymmetric (NCS) space group, which is the paramount precondition for the IR–NLO materials. Thus, over the past decades, continuous efforts have been made to obtain the crystals with NCS space groups by adopting various synthesis approaches, discovering numerous state-of-the-art IR–NLO materials, especially inorganic chalcogenides. Among them, the chemical substitution strategy has proven to be a general and effective method based on known structural prototypes, which can maintain or recombine the crystal structures by a simple element replacement. In this review, 17 representative types (including 6 crystal systems, 27 NCS space groups and about 600 inorganic chalcogenides) ranging from zero-dimensional (0D) molecular to the three-dimensional (3D) framework, and then to mixed-dimensional (MD) structures obtained by the chemical substitution strategy are selected and discussed. The interrelationship of “chemical composition-NCS structure-NLO property” for the 17 representative types is studied and summarized systematically. In addition, the two kinds of structural transformations based on the chemical substitution strategy, including centrosymmetric (CS) to NCS and NCS to NCS, are also described. Finally, we conclude and give the future prospects of this research area.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Achievements on 33 representative IR-NLO examples based on the partial chemical substitution strategy are overviewed.•Structural evolution and performance optimization is studied and ...summarized systematically.•Several useful conclusions and future considerations have been provided.
Infrared nonlinear optical (IR-NLO) crystals as a crucial part in all-solid-state lasers to generate coherent tunable laser beam in the IR range, an important spectral interval for molecular spectroscopy, medical treatment, atmospheric sensing, and scientific researches. Currently, commercially available IR-NLO materials are very rare, limited to chalcopyrite semiconductors (e.g., AgGaS2, AgGaSe2 and ZnGeP2). Unfortunately, all of them present certain limitations, which significantly restrict their applications in high-power laser devices. For this reason, it is extremely urgent to discover new type of IR-NLO compounds with better overall performance. Yet, one of the biggest challenges is how to create the non-centrosymmetric (NCS) crystal structures, which is the prerequisite for the generation of IR–NLO candidates. To accomplish this objective, various approaches have been introduced to design new NCS compounds and many most advanced IR-NLO candidates have been discovered during the past decades. Among them, molecular engineering strategies, especially partial chemical substitution based on the known NCS or centrosymmetric (CS) maternal structures, have been confirmed as a simple yet highly effective method to design and synthesize new high-performance IR-NLO materials. This strategy can not only achieve CS-to-NCS or NCS-to-NCS structural transformation, but also effectively improve the IR-NLO performance of target materials through simple element or basic building unit substitution. In this review, 33 selected examples (including 11 types of CS-to-NCS compounds and 22 types of NCS-to-NCS compounds) ranging from zero-dimensional (0D) isolated clusters to three-dimensional (3D) complex frameworks designed through the partial chemical substitution strategy are discussed and summarized systematically. Finally, some useful conclusions and the future development opportunities and challenges of IR-NLO materials based on the rational partial chemical substitution are briefly discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background and Purpose
Gut microbiota dysbiosis induced by acute pancreatitis (AP) exacerbates pancreatic injury and systemic inflammatory responses. The alleviation of gut microbiota dysbiosis ...through faecal microbiota transplantation (FMT) is considered a potential strategy to reduce tissue damage and inflammation in many clinical disorders. Here, we aim to investigate the effect of gut microbiota and microbiota‐derived metabolites on AP and further clarify the mechanisms associated with pancreatic damage and inflammation.
Experimental Approach
AP rat and mouse models were established by administration of caerulein or sodium taurocholate in vivo. Pancreatic acinar cells were exposed to caerulein and lipopolysaccharide in vitro to simulate AP.
Key Results
Normobiotic FMT alleviated AP‐induced gut microbiota dysbiosis and ameliorated the severity of AP, including mitochondrial dysfunction, oxidative damage and inflammation. Normobiotic FMT induced higher levels of NAD+ (nicotinamide adenine dinucleotide)‐associated metabolites, particularly nicotinamide mononucleotide (NMN). NMN administration mitigated AP‐mediated mitochondrial dysfunction, oxidative damage and inflammation by increasing pancreatic NAD+ levels. Similarly, overexpression of the NAD+‐dependent mitochondrial deacetylase sirtuin 3 (SIRT3) alleviated the severity of AP. Furthermore, SIRT3 deacetylated peroxiredoxin 5 (PRDX5) and enhanced PRDX5 protein expression, thereby promoting its antioxidant and anti‐inflammatory activities in AP. Importantly, normobiotic FMT‐mediated NMN metabolism induced SIRT3–PRDX5 pathway activation during AP.
Conclusion and Implications
Gut microbiota‐derived NMN alleviates the severity of AP by activating the SIRT3–PRDX5 pathway. Normobiotic FMT could be served as a potential strategy for AP treatment.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Severe dendrite growth and high‐level activity of the lithium metal anode lead to a short life span and poor safety, seriously hindering the practical applications of lithium metal batteries. With a ...trisalt electrolyte design, an F‐/N‐containing inorganics–rich solid electrolyte interphase on a lithium anode is constructed, which is electrochemically and thermally stable over long‐term cycles and safety abuse conditions. As a result, its Coulombic efficiency can be maintained over 98.98% for 400 cycles. An 85.0% capacity can be retained for coin‐type full cells with a 3.14 mAh cm−2 LiNi0.5Co0.2Mn0.3O2 cathode after 200 cycles and 1.0 Ah pouch‐type full cells with a 4.0 mAh cm−2 cathode after 72 cycles. During the thermal runaway tests of a cycled 1.0 Ah pouch cell, the onset and triggering temperatures were increased from 70.8 °C and 117.4 °C to 100.6 °C and 153.1 °C, respectively, indicating a greatly enhanced safety performance. This work gives novel insights into electrolyte and interface design, potentially paving the way for high‐energy‐density, long‐life‐span, and thermally safe lithium metal batteries.
An F‐/N‐containing inorganics‐rich solid electrolyte interphase is constructed, which is electrochemically and thermally stable during the long‐term cycles and safety abuse conditions. More than 6 times longer cycles compared with routine cells are achieved in 1.0 Ah pouch‐type cells. The onset and triggering temperatures during the thermal runaway are increased from 70.8 and 117.4 to 100.6 and 153.1 °C, respectively.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Osteosarcoma (OS) is a lethal malignancy of the bone, jeopardizing the life of an enormous population worldwide. There are grand ongoing challenges to improve overall patient survival. Herein, a ...synergetic chemo‐piezodynamic therapy by defect‐engineered lead‐free piezoelectric (K,Na)NbO3 (KNN) is reported, which can generate reactive oxygen species (ROS) to effectively circumvent OS. Significant anti‐tumor effects in human OS cells, and xenograft OS models are observed that almost stop the growth of the tumors after treatment with KNN because of oxygen vacancies‐driven free radical catalysis (namely, the chemodynamic therapy), and those effects are enhanced after introducing ultrasonic vibration enabled by the ultrasound‐triggered piezocatalysis (piezodynamic therapy). Moreover, it is found that KNN induces apoptosis and autophagy of OS cells and shows good histocompatibility on evaluation in mouse models, which has no killing effect on normal cells and no toxic effects on organs in vivo. Both in vitro cellular level evaluation and in vivo OS xenograft assessment have demonstrated that injectable KNN nanocrystals induce cytotoxicity and tumor eradication by the synergy of chemo‐piezocatalytic effects. This study opens an avenue for customized design of high‐tech nanocatalysts by integrating synergetic catalytic effects for therapeutic applications in tumor healthcare.
Defect‐engineered piezoelectric nanocrystals integrated with ultrasonic therapy modality are demonstrated as a low poison effect and highly efficient antitumor reagent for osteosarcoma treatment. This new strategy combines chemocatalytic and piezocatalytic effects to yield massive reactive oxygen species in treating tumors both in primary tumor and lung metastases to address the main issue of toxicity and side effects of conventional antitumor drug therapy.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
It is substantially challenging for non‐centrosymmetric (NCS) Hg‐based chalcogenides for infrared nonlinear optical (IR‐NLO) applications to realize wide band gap (Eg > 3.0 eV) and sufficient ...phase‐matching (PM) second‐harmonic‐generation intensity (deff > 1.0 × benchmark AgGaS2) simultaneously due to the inherent incompatibility. To address this issue, this work presents a diagonal synergetic substitution strategy for creating two new NCS quaternary Hg‐based chalcogenides, AEHgGeS4 (AE = Sr and Ba), based on the centrosymmetric (CS) AEIn2S4. The derived AEHgGeS4 displays excellent NLO properties such as a wide Eg (≈3.04–3.07 eV), large PM deff (≈2.2–3.0 × AgGaS2), ultra‐high laser‐induced damage threshold (≈14.8–15 × AgGaS2), and suitable Δn (≈0.19–0.24@2050 nm), making them highly promising candidates for IR‐NLO applications. Importantly, such excellent second‐order NLO properties are primarily attributed to the synergistic combination of tetrahedral HgS4 and GeS4 functional primitives, as supported by detailed theoretical calculations. This study reports the first two NCS Hg‐based materials with well‐balanced comprehensive properties (i.e., Eg > 3.0 eV and deff > 1.0 × benchmark AgGaS2) and puts forward a new design avenue for the construction of more efficient IR‐NLO candidates.
Two novel non‐centrosymmetric chalcogenides, AEHgGeS4 (AE = Sr and Ba) are developed through the diagonal synergetic substitution strategy, which represents the first two examples breaking through incompatibility between large energy gap (Eg > 3.0 eV) and strong SHG response (deff > 1.0 × benchmark AgGaS2) in Hg‐based chalcogenides, owing to the synergistic effect of highly polarized HgS4 and GeS4 tetrahedra.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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