CELL
·
2021
·
IF 41.584
Liming Yan,Yunxiang Yang,Mingyu Li,Ying Zhang,Litao Zheng,Ji Ge,Yucen C. Huang,Zhenyu Liu,Tao Wang,Shan Gao,Ran Zhang,Yuanyun Y. Huang,Luke W. Guddat,Yan Gao,Zihe Rao,Zhiyong Lou
The capping of mRNA and the proofreading play essential roles in SARS-CoV-2 replication and transcription. Here, we present the cryo-EM structure of the SARS-CoV-2 replication-transcription complex (RTC) in a form identified as Cap(0)-RTC, which couples a co-transcriptional capping complex (CCC) composed of nsp12 NiRAN, nsp9, the bifunctional nsp14 possessing an N-terminal exoribonuclease (ExoN) and a C-terminal N7-methyltransferase (N7-MTase), and nsp10 as a cofactor of nsp14. Nsp9 and nsp12 NiRAN recruit nsp10/nsp14 into the Cap(0)-RTC, forming the N7-CCC to yield cap(0) ( 7Me GpppA) at 5′ end of pre-mRNA. A dimeric form of Cap(0)-RTC observed by cryo-EM suggests an in trans backtracking mechanism for nsp14 ExoN to facilitate proofreading of the RNA in concert with polymerase nsp12. These results not only provide a structural basis for understanding co-transcriptional modification of SARS-CoV-2 mRNA but also shed light on how replication fidelity in SARS-CoV-2 is maintained.
研究领域:
病毒学
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结构生物学
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分子生物学
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DOI
PubMed
高影响因子
MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION
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2022
·Vol. 73
·期 7
·1153-1162
·
IF 1.832
Cunhua Wei,Ge Xu,Jin Yu
A novel triazine derivative, 2, 4-diamino-6-dodecamido-1, 3, 5-triazine (DT), is synthesized by the dehydration condensation of melamine and lauric acid, and its inhibitive performances for the corrosion of Q235 carbon steel in 1 mol/L HCl solution is investigated by electrochemical polarization, electrochemical impedance spectroscopy, scanning electron microscopy, and atomic force microscope. The results reveal that its best inhibition efficiency reaches 96.98% at a concentration of 2.5 g/L. The calculation results of kinetic and thermodynamic parameters indicate that the adsorption of DT on carbon steel surface obeys Langmuir adsorption isotherm with both physical and chemical adsorption. It is demonstrated that long-chain amide (>8C) substituted 1, 3, 5-triazine derivative has the synergistic corrosion inhibition effect of the surface fixation on metal iron and the hydrophobic adsorption layer.
研究领域:
材料科学
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电化学
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表面工程
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DOI
高影响因子
BIODEGRADATION
·
2023
·Vol. 34
·期 4
·371-381
·
IF 3.6
Yue Caixu,Jia Nan,Lv Xueru,Wang Shenghui
3, 5, 6-Trichloro-2-pyridinol (TCP) is a metabolite of the insecticide chlorpyrifos and the herbicide triclopyr, and it is higher toxic than the parent compounds. Microbially-mediated mineralization appears to be the primary degradative pathway and the important biological process of detoxification. However, little information is available on TCP complete metabolic pathways and mechanisms. In this study, the degradation of TCP was studied with a novel strain Micrococcus luteus ML isolated from a stable TCP degrading microbiota. Strain ML was capable of degrading 61.6% of TCP (50 mg/L) and 35.4% of chlorpyrifos (50 mg/L) at 24 h and 48 h under the optimal conditions (temperature: 35 °C; pH: 7.0), respectively. It could also degrade 3, 5-dichloro-2-pyridone, 6-chloropyridin-2-ol, 2-hydroxypyridine and phoxim when provided as sole carbon and energy sources. Seven TCP intermediate metabolites were detected in strain ML and two possible degradation pathways of TCP were proposed on the basis of LC–MS analysis. Both the hydrolytic-oxidative dechlorination pathway and the denitrification pathway might be involved in TCP biodegradation by strain ML. To the best of our knowledge, this is the first report on two different pathways responsible for TCP degradation in one strain, and this finding also provides novel information for studying the metabolic mechanism of TCP in pure culture.
研究领域:
环境微生物学
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生物修复
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代谢组学
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DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2023
·
IF 4.8
Li Huang,Shangying Qin,Yuanjin Xu,Shiqi Cheng,Jin Yang,Yilin Wang
MnO 2 nanosheets (MnO 2 NSs) were prepared and used as both oxidant of 3, 3′, 5, 5′- tetramethylbenzidine (TMB) and recognizer of UA, a simple colorimetric approach for sensitive detection of uric acid (UA) was established. In the medium of weak acid, MnO 2 NSs exhibited strong oxidation capacity and could oxidize colorless TMB to generate a blue oxidation product (oxTMB) with an absorbance signal. However, the introduction of UA could inhibit MnO 2 NSs - mediated TMB oxidation and reduce the formation of oxTMB, resulting in the blue fading and the absorbance weakening. Under the conditions of incubation time 20 min, pH 3.0, TMB 0.5 mM, and MnO 2 NSs 50 μM, the decrease in absorbance was linearly dependent on UA concentration in the range of 0.5–30.0 μM with a detection limit of 0.21 μM. Furthermore, the approach has been applied for determining UA in human urine samples with recoveries between 93.1 and 102.4 % and relative standard deviation less than 3.0 %.
研究领域:
分析化学
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生物医学
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DOI
高影响因子
MOLECULES
·
2020
·Vol. 25
·期 4
·858
·
IF 3.267
Xiaojuan Liu,Yue Wang,Yezhi Chen,Shuting Xu,Qin Gong,Chenning Zhao,Jinping Cao,Chongde Sun
O-methylation of flavonoids is an important modification reaction that occurs in plants.O-methylation contributes to the structural diversity of flavonoids, which have several biological and pharmacological functions. In this study, anO-methyltransferase gene (CrOMT2) was isolated from the fruit peel ofCitrus reticulata, which encoding a multifunctionalO-methyltransferase and could effectively catalyze the methylation of 3’-, 5’-, and 7-OH of flavonoids with vicinal hydroxyl substitutions. Substrate preference assays indicated that this recombinant enzyme favored polymethoxylated flavones (PMF)-type substrates in vitro, thereby providing biochemical evidence for the potential role of the enzyme in plants. Additionally, the cytotoxicity of the methylated products from the enzymatic catalytic reaction was evaluated in vitro using human gastric cell lines SGC-7901 and BGC-823. The results showed that the in vitro cytotoxicity of the flavonoids with the unsaturated C2-C3 bond was increased after being methylated at position 3’. These combined results provide biochemical insight regarding CrOMT2 in vitro and indicate the in vitro cytotoxicity of the products methylated by its catalytic reaction.Keywords:citrus;flavonoids;O-methyltransferase;bioactivity;cytotoxicity
研究领域:
植物生物化学
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药理学
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分子生物学
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细胞生物学
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DOI
PubMed
高影响因子
INTERNATIONAL ENDODONTIC JOURNAL
·
2016
·Vol. 50
·期 9
·885-894
·
IF 2.842
S. Su,Y. Zhu,S. Li,Y. Liang,J. Zhang
Aim To investigate the role of cAMP response element-binding protein (CREB) in the regulation of odonto/osteogenic differentiation of stem cells from the apical papilla (SCAPs). Methodology Stem cells from the apical papilla were obtained from human impacted third molars ( n = 15). Isolated SCAPs were transfected with CREB overexpressing/silenced lentivirus. Transfected cells were stained with alizarin red to investigate mineralized nodule formation. The expression of the mineralization-related genes, alkaline phosphatase (ALP), collagen type I (Col I), runt-related transcription factor 2 (RUNX2), osterix (OSX) and osteocalcin (OCN), was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Protein expression of the odontogenic-related marker dentine sialoprotein (DSP) and the osteogenic-related marker RUNX2 was measured by Western blotting analysis. One-way analysis of variance ( anova ) and Student's t -test were used for statistical analysis ( a = 0.05). Results The overexpression of CREB enhanced mineralized nodule formation and up-regulated ( P < 0.05) the mRNA levels of odonto/osteogenic-related markers, including ALP, Col I, RUNX2, OSX and OCN, and also increased ( P < 0.05) the protein expression of DSP and RUNX2. In contrast, the silencing of CREB inhibited ( P < 0.05) the mineralization capacity of the SCAPs and decreased ( P < 0.05) the expression of odonto/osteogenic-related markers. Conclusion Up-regulation of CREB expression promoted odonto/osteogenic differentiation of SCAPs and provided a potential method for the regeneration of the dentine–pulp complex.
研究领域:
口腔科学
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干细胞生物学
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分子生物学
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DOI
PubMed
高影响因子
THIN SOLID FILMS
·
2019
·
IF 1.888
Jian He,Aisen Li,Yanchun Tao,Ning Chu,Zhixiang Wang,Shuping Xu,Jing Wang,Houyu Zhang,Jingsheng Yu,Weiqing Xu
A two-dimensional (2D) co-crystal composed of 1, 3, 5-trifluoro-2, 4, 6-triiodobenzene and 4, 4′-trimethylenedipyridine via halogen bonding (I···N) was obtained on highly-oriented pyrolytic graphite , and was characterized by scanning tunnelling microscope supplemented by the density functional theory calculation. Its special structure at the interface was further compared with its three-dimensional (3D) co-crystal structure. No orderly structures were observed when Au (111) was applied. The 2D co-crystal grown on the interface is significantly different from the 3D co-crystal. This study is of vital significance in understanding the growth mechanisms of 2D functional co-crystals.
研究领域:
材料科学
·
化学
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DOI
高影响因子
JOURNAL OF GENERAL AND APPLIED MICROBIOLOGY
·
2020
·
IF 1.442
Nengqiang Wang,Zhen Luo,Kaiqin Li,Yingcui Xu,Cheng Peng
A strain LZ1, which showed efficient asymmetric reduction of 3,5-bis(trifluoromethyl) acetophenone to enantiopure (S)-[3,5-bis(trifluoromethyl)phenyl]ethanol, which is the key intermediate for the synthesis of a receptor antagonist and antidepressant, was isolated from a soil sample. Based on its morphological, 16S rDNA sequence, and phylogenetic analysis, the strain LZ1 was identified to be Sphingomonas sp. LZ1. To our knowledge, this is the first reported case of the species Sphingomonas exhibiting stricter S-enantioselectivity and its use for the asymmetric reduction of 3,5-bis(trifluoromethyl) acetophenone. Some key reaction parameters involved in the bioreduction catalyzed by whole cells of Sphingomonas sp. LZ1 were subsequently optimized, and the optimized conditions for the synthesis of (S)-[3,5-bis(trifluoromethyl)phenyl]ethanol were determined to be as follows: phosphate buffer pH 7.5, 70 mM of 3,5-bis(trifluoromethyl) acetophenone, 30 g/L of glucose as a co-substrate, 300 g (wet weight)/L of resting cell as the biocatalyst, and a reaction for 24 h at 30°C and 180 rpm. Under the above conditions, a best yield of 94% and an excellent enantiomeric excess of 99.6% were obtained, respectively. Sphingomonas sp. LZ1 could also asymmetrically reduce a variety of prochiral ketones to their corresponding optical alcohols with excellent enantioselectivity. These results indicated that Sphingomonas sp. LZ1 had a remarkable capacity to reduce 3,5-bis(trifluoromethyl)acetophenone to its corresponding (S)-[3,5-bis(trifluoromethyl)phenyl]ethanol, and might be a new potential biocatalyst for the production of valuable chiral alcohols in industry.
研究领域:
微生物学
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生物催化
·
有机合成
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DOI
PubMed
高影响因子
Scientific Reports
·
2016
·Vol. 6
·期 1
·1-7
·
IF 5.228
Guo Longhua,Xu Shaohua,Ma Xiaoming,Qiu Bin,Lin Zhenyu,Chen Guonan
Colorimetric enzyme-linked immunosorbent assay utilizing 3′-3-5′-5-tetramethylbenzidine(TMB) as the chromogenic substrate has been widely used in the hospital for the detection of all kinds of disease biomarkers. Herein, we demonstrate a strategy to change this single-color display into dual-color responses to improve the accuracy of visual inspection. Our investigation firstly reveals that oxidation state of 3′-3-5′-5-tetramethylbenzidine (TMB 2+ ) can quantitatively etch gold nanoparticles. Therefore, the incorporation of gold nanoparticles into a commercial TMB-based ELISA kit could generate dual-color responses: the solution color varied gradually from wine red (absorption peak located at ~530 nm) to colorless, and then from colorless to yellow (absorption peak located at ~450 nm) with the increase amount of targets. These dual-color responses effectively improved the sensitivity as well as the accuracy of visual inspection. For example, the proposed dual-color plasmonic ELISA is demonstrated for the detection of prostate-specific antigen (PSA) in human serum with a visual limit of detection (LOD) as low as 0.0093 ng/mL.
研究领域:
生物医学工程
·
诊断学
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产品关联
DOI
PubMed
高影响因子
Chinese Journal of Natural Medicines
·
2017
·
IF 1.667
Qiong YU,Li-Long JIANG,Na LUO,Ya-Xi FAN,Jiang MA,Ping LI,Hui-Jun LI
Polygoni Multiflori Radix (PMR) has been commonly used as a tonic in China for centuries. However, PMR-associated hepatotoxicity is becoming a safety issue. In our previous in vivo study, an interaction between stilbenes and anthraquinones has been discovered and a hypothesis is proposed that the interaction between stilbene glucoside-enriching fraction and emodin may contribute to the side effects of PMR. To further support our previous in vivo results in rats, the present in vitro study was designed to evaluate the effects of 2, 3, 5, 4′-tetrahydroxystilbene-2- O-β -D-glucopyranoside (TSG) on the cellular absorption and human liver microsome metabolism of emodin. The obtained results indicated that the absorption of emodin in Caco-2 cells was enhanced and the metabolism of emodin in human liver microsomes was inhibited after TSG treatment. The effects of the transport inhibitors on the cellular emodin accumulation were also examined. Western blot assay suggested that the depressed metabolism of emodin could be attributed to the down-regulation of UDP-glucuronosyltransferases (UGTs) 1A8, 1A10, and 2B7. These findings definitively demonstrated the existence of interaction between TSG and emodin, which provide a basis for a better understanding of the underlying mechanism for PMR-induced liver injury.
研究领域:
药理学
·
毒理学
·
分子生物学
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DOI
PubMed
高影响因子
Materials Research Express
·
2016
·Vol. 3
·期 5
·055002
·
IF 0.968
Xiaodong Deng,Xiaonan Liu,Tao Duan,Wenkun Zhu,Zao Yi,Weitang Yao
Bayberry tannin (BT)–reduced graphene oxide (rGO) sponges have been prepared by self–assembly, with bayberry tannin serving as both reductant and surface functionalization agent. The synthetic method is based on the self-assembly of graphene oxide (GO) sheets into porous hydrogel structures. By varying the weight ratio of GO to BT, a series of sorbents with different densities of organic molecules have been obtained and applied to remove Sr2+ from aqueous solutions. Adsorption isotherms (Langmuir and Freundlich) and kinetics (pseudo-first order and pseudo-second order) have been investigated to discuss the sorption performance of rGO/BT sponges. The rGO/BT (w/w 1:1) sponge shows excellent adsorption properties for Sr2+, with maximum capacities of 67.98 mg g−1. The adsorption capacity is much higher than those in classic Sr2+ adsorbents, such as hydrous manganese dioxide, Egyptian soils, Hydroxyapatite nanoparticles, sodium hexa-titanate nanofibers, Graphene oxide, artificially altered phlogopite(Ca–Phl), and PB/Fe3O4/GO. Adsorption mechanisms have been examined using the x-ray photoelectron spectra of sorbents before and after Sr2+ adsorption, and the results indicate that the sorption of Sr2+ on GO and GO/BT 1.0 is largely depended on oxygen functional groups. The results show that the GO/BT sponge is a promising candidate for adsorbing Sr2+ ion.
研究领域:
材料科学
·
环境科学
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产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2023
·
IF 4.3
Zhangxu Zhou,Yulong Liu,Taocui Yan,Shixin Tu,Hongli Guo,Jin Zhou,Ziqian Ye,Zhilun Zhang,Keyu Li,Pei Zhao,Guowei Zuo,Baoru Han
Breast milk, as the most ideal food for infants, contains the main nutrients to meet the growth and development of infants. Lactose is an essential energy source in breast milk, the concentration of which varies based on a variety of circumstances, including maternal diet and lactation stage. Studies demonstrated that lactose content could affect the development of the brain and gut immunity of infants. We integrated the enzyme cascade reaction with colorimetry , and then established a data-prediction model utilizing multi-point absorbance analysis and a back-propagation (BP) neural network. Lactose underwent an enzymatic cascade to generate H 2 O 2, which oxidized the chromatic substrate 3,3′5,5′-tetramethylbenzidine (TMB). Absorbance at several time intervals and wavelengths was measured. Different from the traditional end-point detection methods and their single input data model, the absorbance data were detected at various time points and then fitted by BP neural network in this research. The detection of lactose in breast milk showed an average recovery rate of 99.14%. Meanwhile, our strategy is time-efficient and required no complex sample preparation processes. The robust nonlinear mapping and high fault tolerance of the BP neural network significantly enhances the stability and precision of the colorimetric analysis . Overall, this approach may be used for low-cost, convenient, and accurate lactose quantification in breast milk.
研究领域:
分析化学
·
生物化学
·
神经网络
·
营养科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）