JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
·
2023
·
IF 5.2
Pei Li,Zhishuang Yang,Ting Lei,Yujie Dai,Yang Zhou,Dekang Zhu,Hongyan Luo
Objectives: To elucidate the role of a novel carbapenem-hydrolysing class D β-lactamase (RAD-1) from Riemerella anatipestifer. Methods: We applied WGS and bioinformatic analysis to screen putative β-lactamase genes in R. anatipestifer SCVM0004. A putative class D β-lactamase gene was cloned into pET24a and transferred into Escherichia coli BL21 (DE3) for antibiotic susceptibility determination and protein purification. Meanwhile, the purified native protein was used to determine the enzymatic activities. Results: A class D β-lactamase, RAD-1, was identified in the genome of R. anatipestifer SCVM0004. It was distinct from all characterized class D β-lactamases (≤42% amino acid sequence identity). Searching in GenBank showed that blaRAD-1 was widely disseminated among R. anatipestifer. Genomic environment analysis indicated that the chromosomal structures of blaRAD-1-located regions were relatively conserved. Expression of RAD-1 in E. coli results in elevated MICs for various β-lactam antibiotics, including penicillins, extended-spectrum cephalosporins, a monobactam and carbapenems. Moreover, kinetic analysis of purified RAD-1 revealed: (i) high-level activity against penicillins; (ii) highest affinity for carbapenems; (iii) moderate hydrolysis of extended-spectrum cephalosporins and a monobactam; and (iv) no activity for oxacillin and cefoxitin. Conclusions: This study identified a novel chromosomally located class D carbapenemase RAD-1 (Bush-Jacoby functional group 2def) in R. anatipestifer SCVM0004. Moreover, bioinformatic analysis confirmed that the RAD-1 was widely prevalent and conserved in R. anatipestifer.
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PubMed
高影响因子
HYDROMETALLURGY
·
2020
·
IF 3.338
Shiwei He,Ruidong Xu,Li Sun,Youqi Fan,Zhuo Zhao,Huan Liu,Huihong Lv
In this study, a new anode based on Pb-0.3%Ag/α-PbO 2 /β-PbO 2 -Co 3 O 4 composite is proposed and its performance is compared with that of the traditional Pb-1wt%Ag anode during long-term zinc electrowinning . The electrocatalytic activity of the new anode for the oxygen evolution reaction (OER) initially decreased and then gradually increased, which was attributed to the phase transition occurring at the surface of the anode, and its corrosion resistance was gradually improved with the progress of electrowinning. Further, the electrochemical characteristics, cell voltage , current efficiency , and energy consumption of the two anodes were evaluated after 16 days of electrowinning. The OER electrocatalytic activity and corrosion resistance of the new anode were observed to be higher than those of the traditional anode. In addition, the cell voltage and power consumption of the new anode were significantly lower than those of the traditional anode. Furthermore, compared to the traditional anode, the energy consumption for producing 1 t of zinc was reduced by 358.13 kWh based on the new anode.
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高影响因子
Chemical Engineering and Processing-Process Intensification
·
2024
·
IF 3.8
Zifei Yan,Grace Dai Zhen Lee,Jian Deng,Guangsheng Luo
The synthesis of terminal epoxides, which are vital components in pharmaceuticals and resins, often involves dehydrochlorination of β-chlorohydrins. Although intrinsic kinetics indicate that the dehydrochlorination reaction in the presence of sodium hydroxide could be very rapid, the practical implementation could always be hindered by long reaction time and low conversion rate. Extended contact between the product and the alkaline solution can lead to hydrolysis of the epoxy group, thus necessitating the process intensification to realize higher production efficiency and selectivity. Here, by characterizing thermodynamic equilibrium data and in-situ recording of the reaction that proceeded in a constant interphase reactor, the heterogeneous dehydrochlorination is demonstrated to occur primarily in the organic phase, and the overall reaction rate depends on the equilibrium concentration of sodium alkoxides. This finding, which is fundamentally different from the traditional view that chlorohydrin is first dissolved in the aqueous phase and then reacts with NaOH, leads us to use inert alcohols to assist in the extraction of NaOH. Based on this method, the reaction time can be reduced over 80 % both in batch and continuous reactors. Besides, the method is demonstrated to be effective in the dehydrochlorination of five different long-chain β-chlorohydrins.
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高影响因子
ChemistrySelect
·
2022
·Vol. 7
·期 36
·e202202508
·
IF 2.307
Meifeng Wang,Liyin Zhang,Yiqun Li,Liuqun Gu
Graphical An unprecedent “mixing and stand” anomerization of D-glucose pentaacetate in solid state was discovered after simple premixing in solvent and then removal of solvent, and the reaction proceeded continuously to full conversion without stirring or mechanomixing. Gram scale reaction was demonstrated and a new mechanism was also proposed. Anomerization of glycosides was rarely performed under basic condition. Here, an imidazole promoted anomerization of β-D-glucose pentaacetate in solid state at room temperature was discovered. This unprecedent anomerization occurred after simple premixing and reaction proceeded continuously in solid state to full conversion without stirring or mechanomixing. Full conversion of all β-forms in the mixture (α:β=2.2 : 1) into α-forms only was demonstrated at 1 gram scale. A proposed mechanism involved with inter/intramolecular acyl transfer promoted by imidazoles in a concerted manner may promote the discovery of more new transformations in solid state.
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高影响因子
Desalination and Water Treatment
·
2024
·
IF 1
Yang Liu,Yuanyuan Wang,Jie Ma,Runping Han
ABSTRACT In this study, peanut shell was modified using β-cyclodextrin (β-CD) and citric acid to improve the adsorption capacity for removal of lead ion (Pb 2+ ) and bisphenol S (BPS) from solution in batch mode. Scanning electron microscopy, Fourier-transform infrared spectroscopy, elemental analysis, X-ray fluorescence analysis, specific surface area analysis, thermogravimetric analysis, etc were used to characterize the adsorbent before and after modification. The results showed that the adsorbent was successfully modified. The adsorption results of Pb 2+ and BPS on β-CD-PS indicated that acidic conditions were not conducive to the adsorption of Pb 2+ , the adsorption of BPS basically remained unchanged at pH 2~7, and alkaline conditions were not conducive to the adsorption. The presence of salt had a negative effect on Pb 2+ , but had no effect on the adsorption of BPS. The Langmuir and Koble–Corrigan models could predict the equilibrium adsorption process of Pb 2+ while Temkin and Koble–Corrigan models could describe the equilibrium adsorption process of BPS. The adsorption quantity from experiments is 89.6 mg·g –1 for Pb 2+ and 16.2 mg·g –1 for BPS at 293 K, respectively. The adsorption process of Pb 2+ was consistent with the pseudo-first-order and Elovich models, indicating the presence of ion-exchange in the adsorption process; the adsorption of BPS was consistent with the pseudo-second-order model, indicating that chemisorption was the main rate-controlling step. Thermodynamic studies indicated that the adsorption of Pb 2+ was a spontaneous and endothermic reaction with increasing entropy, while the adsorption of BPS was a spontaneous and exothermic reaction with decreasing entropy. 0.1 mol·L –1 HNO 3 could desorb and regenerate the β-CD-PS adsorbed Pb 2+ for three times, and 75% C 2 H 5 OH had a better desorption and regeneration effect for BPS loaded β-CD-PS. β-CD-PS can effectively remove the lead ion and BPS from mixtures and the study can provide the basis for the effective utilization of peanut shell in environmental remediation.
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高影响因子
Microbiology Spectrum
·
2024
·Vol. 12
·期 10
·
IF 3.7
Karl A. Glen,Iain L. Lamont
Pseudomonas aeruginosa is a highly problematic opportunistic pathogen that causes a range of different infections. Infections are commonly treated with β-lactam antibiotics, including cephalosporins, monobactams, penicillins, and carbapenems, with carbapenems regarded as antibiotics of last resort. Isolates of P. aeruginosa can contain horizontally acquired bla genes encoding β-lactamase enzymes, but the extent to which these contribute to β-lactam resistance in this species has not been systematically quantified. The overall aim of this research was to address this knowledge gap by quantifying the frequency of β-lactamase-encoding genes in P. aeruginosa and by determining the effects of β-lactamases on susceptibility of P. aeruginosa to β-lactams. Genome analysis showed that β-lactamase-encoding genes are present in 3% of P. aeruginosa but are enriched in carbapenem-resistant isolates (35%). To determine the substrate antibiotics, 10 β-lactamases were expressed from an integrative plasmid in the chromosome of P. aeruginosa reference strain PAO1. The β-lactamases reduced susceptibility to a variety of clinically used antibiotics, including carbapenems (meropenem, imipenem), penicillins (ticarcillin, piperacillin), cephalosporins (ceftazidime, cefepime), and a monobactam (aztreonam). Different enzymes acted on different β-lactams. β-lactamases encoded by the genomes of P. aeruginosa clinical isolates had similar effects to the enzymes expressed in strain PAO1. Genome engineering was used to delete β-lactamase-encoding genes from three carbapenem-resistant clinical isolates and increased susceptibility to substrate β-lactams. Our findings demonstrate that acquired β-lactamases play an important role in β-lactam resistance in P. aeruginosa, identifying substrate antibiotics for a range of enzymes and quantifying their contributions to resistance.
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DOI
PubMed
高影响因子
Advanced Science
·
2024
·
IF 14.3
Lijiao He,Xiao Zhang,Shengwei Zhang,Yi Wang,Weichao Hu,Jie Li,Yunyi Liu,Yu Liao,Xue Peng,Jianjun Li,Haiyan Zhao,Liting Wang,Yang-Fan Lv,Chang-Jiang Hu,Shi-Ming Yang
Persistent H. pylori infection triggers the repair program of the mucosa, such as spasmolytic polypeptide-expressing metaplasia (SPEM). However, the mechanism underlying the initiation of SPEM in gastric tissues by H. pylori remains unclear. Here, an increase in telomerase reverse transcriptase (TERT) protein expression is observed in chief cells upon infection with cagA -positive H. pylori . Tert knockout significantly ameliorated H. pylori -induced SPEM and single-cell RNA sequencing demonstrated that the Wnt/β-Catenin pathway is suppressed in gastric cells with Tert knockout. Mechanism study revealed that CagA elevated TERT abundance by disrupting the interaction between TERT and its novel E3 ligase, SYVN1. Interestingly, Nitazoxanide effectively relieved SPEM via inhibition of the Wnt/β-Catenin signaling in vivo. This results clarified the mechanism underlying which CagA activated the TERT/Wnt/β-Catenin pathway, thus promoting the dedifferentiation of chief cells and the occurrence of SPEM in gastric mucosa. This highlights a molecular basis for targeting CagA-activated Wnt signaling in chief cells for the treatment of gastric precancerous lesions.
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PubMed
高影响因子
Laser & Photonics Reviews
·
2024
·
IF 9.8
Hui Zhu,Yanan Li,Yuexiang Xi,Chunli Xin,Cheng Zhou,Zhe Yang,Lang Ruan,Yanyue Li,Yao Peng,Maxim S. Molokeev,Andrey Zolotov,Jing Wang,Zhi Zhou,Mao Xia
β-Al 2 O 3 phosphors show good optical properties for highly symmetric lattices and dense frameworks. Here, an abnormal lattice shrinkage phenomenon is found in BaMg 1-x Zn x Al 9.8 O 17 : Cr 3+ (BM 1-x Z x A: Cr 3+ ) phosphors, which can be attributed to the variation in the covalency of the chemical bond. Accordingly, the denser crystal structure caused by the abnormal shrinkage improves the luminescent intensity (67%↑) and the thermal stability (69%→76%@150 °C). Internal/external quantum efficiency (IQE/EQE) of BZA: 0.2Cr 3+ reaches 95% and 52.7%, respectively. In addition, the preferential occupation of the Cr 3+ ion is discussed through the crystal field strength calculation, low-temperature spectra, and fluorescent lifetime. The unique spectrum of the phosphor derives from the occupation of Cr 3+ on the octahedral sites (Al4 and Al1) and the formation of Cr 3+ -Cr 3+ coupling pairs. Finally, the high matching rate between the absorption curve of plant pigment P fr and the EL spectrum of the as-prepared pc-LED expresses that it can be applied in plant lighting.
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高影响因子
POLYHEDRON
·
2018
·
IF 2.067
Aohui Yang,Huijun Liu,Zhendong Li,Liuxing Li,Wei Li,Kai Liu
Cyclodextrin metal–organic frameworks (K-CD-MOFs) based on renewable β-cyclodextrin molecules (β-CD) and alkali metals (K) was prepared by modified methanol vapor diffusion method at temperature of 50 °C for 6 h, and this can shorten the reaction time compared with the previous reported. Then the quercetin and emodin were selected to investigate the loading characteristics of K-CD-MOFs and drugs adsorption behavior was studied by changing the reaction time, temperatures, MOFs quality, initial drugs concentration and pH. In results, the crystals showed high adsorption (150.2 and 199.8 mg/g) when the reaction time both at 48 h, the temperatures of 35 and 45 °C, 30 mg K-CD-MOFs, the initial concentration of quercetin and emodin was 3.2 and 2.3 mg/ml and pH 6. Furthermore, the adsorption kinetics of drugs matched a pseudo-second-order model well and chemisorption of quercetin and emodin. Most importantly, XRD pattern analysis showed that the drug loading process did not destroy the crystallinity of the material. In summary, on the basis of optimizing the synthesis of K-CD-MOFs, the crystal stability and drugs adsorption properties were evaluated, which provided a basis for the potential drug delivery.
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高影响因子
CHIRALITY
·
2020
·Vol. 32
·期 8
·1080-1090
·
IF 2.171
Lunan Zhu,Junchen Zhu,Xiaotong Sun,Yaling Wu,Huiying Wang,Lingping Cheng,Jiawei Shen,Yanxiong Ke
Novel chiral selectors based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5-dimethyl phenylcarbamoylated β-cyclodextrin (β-CD) chiral stationary phase (CSP) and 9- O -( tert -butylcarbamoyl)-QN-based CSP (QN-AX). Fmoc-protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD-based CSP and QN/QD-based CSPs have broader application range than β-CD-based CSP or QN/QD-based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc-amino acids accompanied by the synergistic effect of β-CD moiety, which lead to the different enantioseparation of β-CD-QN-based CSP and β-CD-QD-based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin-based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β-CD-based CSP for certain samples.
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高影响因子
FOOD HYDROCOLLOIDS
·
2024
·
IF 11
Xingran Kou,Xiwei Xu,Nan Gao,Yunchong Zhang,Xin Huang,Feng Chen,Qinfei Ke,Qingran Meng
Supramolecular chemistry of cyclodextrins (CDs) inclusion complexes is a hot research topic at present, but current studies often focus on the host-guest interaction between CDs and hydrophobic substances, while ignoring the self-assembly behavior of the host and guest during the inclusion process. Based on the spatial structures, six representative terpenes were selected in this study, and the stoichiometric ratio between terpenes and β-cyclodextrin (β-CD) was investigated by isothermal titration calorimetry (ITC) method. Meanwhile, the constructed inclusion complexes (ICs) were characterized by nuclear magnetic resonance , X-ray diffraction, scanning electron microscope , etc. On this basis, the assembly process of β-CD and terpenes was investigated firstly by molecular simulation method, and the inclusion process between β-CD and terpenes was further studied in terms of the formation of individual ICs and ICs aggregates. Results showed that hydrophobic interaction and van der Waals force were the main driving forces of the reaction between terpenes and β-CD, and the formation of ICs, β-CD molecule aggregation, terpene aggregation, and ICs aggregation occurred simultaneously during the inclusion process of terpenes and β-CD. To sum up, this study may provide certain thinking and reference for the subsequent supramolecular chemical research on CDs.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Lan Guo,Yuan Liu,Rongmei Kong,Guang Chen,Hao Wang,Xiuli Wang,Lian Xia,Fengli Qu
β-Glucuronidase (β-GCU) is closely related to the occurrence of multiple diseases, and it has been applied as a biomarker and therapeutic target in clinical diagnosis. However, reliable methods with high selectivity and sensitivity for monitoring β-GCU are still lacked. Herein, we designed a novel fluorescent nanoprobe, rhodamine B encapsulated MOF-5 (RhB@MOF-5) for the first time, to detect β-GCU through the synergistic effect of inner filter effect (IFE) and static quenching effect (SQE) by employing 4-nitrophenyl-β-D-glucuronide (PNPG) as the substrate. After encapsulating into MOF-5, the fluorescence emission of RhB at 550 nm excited by 320 nm was greatly enhanced. The major overlap between the fluorescence excitation spectrum of RhB@MOF-5 (about 320 nm) and the ultraviolet absorption spectrum of PNPG (about 310 nm) lead to PNPG being a good IFE absorber in this sensing system. Under the optimized conditions, the excitation spectrum of the RhB@MOF-5 could be absorbed by PNPG, resulting in the dramatically decrease of fluorescence emission. After adding β-GCU into the system, the substrate of PNPG would be enzymatic hydrolyzed to p -nitrophenol (PNP) and glucose, then the IFE disappearance and the fluorescence recovered. The current sensing platform was interference-free and exhibited a broad linearity relationship for β-GCU range of 0.1–10 U L −1 (R 2 = 0.9957) with a limit of detection as low as 0.03 U L −1 , which was reduced by more than one orders compared with the reported methods. Moreover, the encapsulation of dyes using porous nanoparticles to achieve some tailor-made characteristics will enrich experimental design inspiration.
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高影响因子
危险品化学品经营许可证（带存储）