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The enzymatic biosynthesis of acylated steroidal glycosides and their cytotoxic activity

Acta Pharmaceutica Sinica B 2018年第6期8卷 981-994页

作者： Ming Liu jian-Qiang kong State Key Laboratory of Bioactive Substance and Function of Natural Medicines & Ministry of Health Key Laboratory of Biosynthesis of Natural Products Institute of Materia Medica Chinese Academy of Medical Sciences & Peking Union Medical College

Herein we describe the discovery and functional characterization of a steroidal glycosyltransferase(SGT) from Ornithogalum saundersiae and a steroidal glycoside acyltransferase(SGA) from Escherichia coli and their application in the biosynthesis of acylated steroidal glycosides(ASGs). Initially,an SGT gene, designated as OsSGT1, was isolated from O. saundersiae. OsSGT1-containing cell free extract was then used as the biocatalyst to react with 49 structurally diverse drug-like compounds. The recombinant OsSGT1 was shown to be active against both 3β-and 17β-hydroxyl steroids. Unexpectedly,in an effort to identify OsSGT1, we found the bacteria lacA gene in lac operon actually encoded an SGA,specifically catalyzing the acetylations of sugar moieties of steroid 17β-glucosides. Finally, a novel enzymatic two-step synthesis of two ASGs, acetylated testosterone-17-O-β-glucosides(AT-17β-Gs) and acetylated estradiol-17-O-β-glucosides(AE-17β-Gs), from the abundantly available free steroids using OsSGT1 and EcSGA1 as the biocatalysts was developed. The two-step process is characterized by EcSGA1-catalyzed regioselective acylations of all hydroxyl groups on the sugar unit of unprotected steroidal glycosides(SGs) in the late stage, thereby significantly streamlining the synthetic route towards ASGs and thus forming four monoacylates. The improved cytotoxic activities of 30-acetylated testosterone17-O-β-glucoside towards seven human tumor cell lines were thus observable.

关键词： Steroidal glycosyltransferase Steroidal glycoside acyltransferase Ornithogalum saundersiae Acylated steroidal glycosides LacA

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Steroids hydroxylation catalyzed by the monooxygenase mutant 139-3 from Bacillus megaterium BM3

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Acta Pharmaceutica Sinica B 2017年第4期7卷 510-516页

作者： Xing Liu jian-qiang kong State Key Laboratory of Bioactive Substance and Function of Natural Medicines&Ministry of Health Key Laboratory of Biosynthesis of Natural Products Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

The search of new substrates with pharmaceutical and industrial potential for biocatalysts including cytochrome P450 enzymes is always challenging. Cytochrome P450 BM3 mutant 139-3, a versatile biocatalyst, exhibited hydroxylation activities towards fatty acids and alkanes. However, there were limited reports about its hydroxylation activity towards steroids. Herein, an Escherichia coli-based whole-cell extract containing the recombinant 139-3 protein was used as the biocatalyst to screen 13 steroids. Results revealed that 139-3 was able to specifically hydroxylate androstenedione (1) at 1α-position, generating a hydroxylated steroid 1α-OH-androstenedione (1a). To investigate whether C-1α hydroxylation catalyzed by BM3 mutant 139-3 could be industrially used, an optimization of catalyzing conditions was performed. Accordingly, the BM3 mutant 139-3 enzyme was observed to display maximum activity at 37 °C, under pH 7.0 for 4 h, with 37% transformation rate. Moreover, four 139-3 variants were generated by random mutagenesis with the aim of improving its activity and expanding substrate scope. Surprisingly, these mutants, sharing a common mutated site R379S, lost their activities towards androstenedione (1). These data clearly indicated that arginine residue located at site 379 played key role in the hydroxylation activities of 139-3. Overall, these new findings broadened the substrate scope of 139-3 enzyme, thereby expanding its potential applications as a biocatalyst on steroids hydroxylation in pharmaceutical industry.

关键词： Cytochrome P450 BM3 139-3 Steroids hydroxylation 1α-OH-androstenedione Biocatalyst

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The phosphorescence nanocomposite thin film with rich oxygen vacancy:Towards sensitive oxygen sensor

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Chinese Chemical Letters 2022年第8期33卷 3977-3980页

作者： jian Yao jian kong Lingwei kong Xinrui Wang Wenying Shi Chao Lu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Cosmetic China National Light IndustryBeijing Technology and Business UniversityBeijing 100048China

Organic room temperature phosphorescent(ORTP)materials provide an exciting research direction for phosphorescent oxygen(O_(2)) sensors due to their high sensitivity and rapid response to O_(2).However,most pure ORTP materials are tightly-packed aromatic compound crystals in a face-to-face manner,which largely prohibits effective O_(2) diffusion for ***,how to solve this contradiction still faces huge ***,the use of organic phosphorescent indicator carbon dots(CDs),inorganic matrix layered double hydroxides(LDHs)and polymers(PVA)successfully prepared an ultra-long RTP composite film whose phosphorescence decay intensity is linearly related to O_(2) *** importantly,the use of the abundant O_(2) defects(Vo)on the surface of the inorganic matrix LDHs to adsorb O_(2),which further accelerates the phosphorescence quenching of the thin film and improves the O_(2) *** strategy will provide the possibility to develop high-sensitivity phosphorescent O_(2) sensors from a new perspective.

关键词： Layered double hydroxides Carbon dots Nanocomposite thin film Phosphorescence Oxygen vacancy Oxygen-sensing

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Self-Supervised Graph Neural Networks for Accurate Prediction of Néel Temperature

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Chinese Physics Letters 2022年第6期39卷 5-11页

作者： jian-Gang kong Qing-Xu Li jian Li Yu Liu Jia-Ji Zhu School of Science Chongqing University of Posts and TelecommunicationsChongqing 400065China Institute for Advanced Sciences Chongqing University of Posts and TelecommunicationsChongqing 400065China Southwest Center for Theoretical Physics Chongqing UniversityChongqing 401331China Inspur Electronic Information Industry Co. LtdBeijing 100085China

Antiferromagnetic materials are exciting quantum materials with rich physics and great potential for *** the other hand, an accurate and efficient theoretical method is highly demanded for determining critical transition temperatures, Néel temperatures, of antiferromagnetic materials. The powerful graph neural networks(GNNs) that succeed in predicting material properties lose their advantage in predicting magnetic properties due to the small dataset of magnetic materials, while conventional machine learning models heavily depend on the quality of material descriptors. We propose a new strategy to extract high-level material representations by utilizing self-supervised training of GNNs on large-scale unlabeled datasets. According to the dimensional reduction analysis, we find that the learned knowledge about elements and magnetism transfers to the generated atomic vector representations. Compared with popular manually constructed descriptors and crystal graph convolutional neural networks, self-supervised material representations can help us to obtain a more accurate and efficient model for Néel temperatures, and the trained model can successfully predict high Néel temperature antiferromagnetic materials. Our self-supervised GNN may serve as a universal pre-training framework for various material properties.

关键词： utilizing networks neural

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Development of Zn^(2+)-controlled expression system for lactic acid bacteria and its application in engineered probiotics

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Synthetic and Systems Biotechnology 2024年第1期9卷 152-158页

作者： Xiaoning Xu Lingwen Zhang Yue Cui jian kong Tingting Guo State Key Laboratory of Microbial Technology Shandong UniversityNo.72 Binhai RoadQingdao266237PR China

Lactococcus lactis and Streptococcus thermophilus are considered as ideal chassis of engineered probiotics,while food-grade genetic tools are limited in those ***,a Zn^(2+)-controlled gene expression(ZICE)system was identified in the genome of *** CGMCC7.179,including a transcriptional regulator sczAst and a promoter region of cation transporter czcD(PczcDst).Specific binding of the SczAst to the palindromic sequences in PczcDst was demonstrated by EMSA analysis,suggesting the regulation role of SczAst on *** evaluate their possibility to control gene expression in vivo,the sczAst-PczcDst was employed to drive the expression of green fluorescence protein(GFP)gene in *** NZ9000 and *** CGMCC7.179,*** of the transformants could express GFP under Zn^(2+)induction,while no fluorescence without Zn^(2+)*** optimal conditions,Zn^(2+)was used at a final concentration of 0.8 mM in *** and 0.16 mM in *** at OD600 close to 0.4,and omitting yeast extract powder in the medium unexpectedly improved GFP expression level by *** the help of the ZICE system,engineered *** and *** strains were constructed to secret cytokine interleukin-10(IL-10)with immunogenicity,and the IL-10 content in the supernatant of the engineered *** was 59.37%of that under the nisin controlled expression *** study provided a tightly controlled expression system by the food-grade inducer Zn^(2+),having potential in development of engineered probiotics.

关键词： Lactococcus lactis Streptococcus thermophilus Food-grade expression system Engineered probiotic

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Parameters Sensitivity Characteristics of Highly Integrated Valve-Controlled Cylinder Force Control System

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 159-175页

作者： Kai-Xian Ba Bin Yu Xiang-Dong kong Chun-He Li Qi-Xin Zhu Hua-Long Zhao Ling-jian kong School of Mechanical Engineering Yanshan University State Key Laboratory of Fluid Power and Mechatronic System Zhejiang University Columbia University

Nowadays, a highly integrated valve?controlled cylinder(HIVC) is applied to drive the joints of legged robots. Although the adoption of HIVC has resulted in high?performance robot control, the hydraulic force system still has problems, such as strong nonlinearity, and time?varying parameters. This makes HIVC force control very diffcult and complex. How to improve the control performance of the HIVC force control system and find the influence rule of the system parameters on the control performance is very significant. Firstly, the mathematical model of HIVC force control system is established. Then the mathematical expression for parameter sensitivity matrix is obtained by applying matrix sensitivity analysis(PSM). Then, aimed at the sinusoidal response under(three factors and three levels) working conditions, the simulation and the experiment are conducted. While the error between the simulation and experiment can’t be avoided. Therefore, combined with the range analysis, the error in the two performance indexes of sinusoidal response under the whole working condition is analyzed. Besides, the sensitivity variation pattern for each system parameter under the whole working condition is figured out. Then the two sensitivity indexes for the three system parameters, which are supply pressure, proportional gain and initial displacement of piston, are proved experimentally. The proposed method significantly reveals the sensitivity characteristics of HIVC force control system, which can make the contribution to improve the control performance.

关键词： Highly integrated valve?controlled cylinder system Force control system Matrix sensitivity analysis Orthogonal test design Sensitivity index

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Intravascular treatment for abnormal catheter positioning of port-a-cath system in the subclavian vein:A single-center study

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Journal of Interventional Medicine 2022年第2期5卷 103-110页

作者： Yong Li jianxi Guo Yanfang Zhang jian kong Department of Interventional Radiology Shenzhen People’s Hospital (Second Clinical Medical College of Jinan University First Affiliated Hospital of Southern University of Science and Technology)ShenzhenChina

Objective:This study aimed to explore the incidence of abnormal catheter positioning and the effectiveness and safety of intravascular adjustment or removal of abnormally positioned catheters through percutaneous *** and methods:A retrospective analysis was conducted on 58 patients with abnormal catheter positioning,treated between January 2009 and June *** adjustment of the migrated catheters and removal of the fractured catheters were performed through percutaneous puncture using a pigtail catheter,cobra catheter,and gooseneck ***:Of the 58 cases,there were 23 cases of catheter migration and 35 cases of catheter *** incidence of abnormal catheter positioning was 3.0%,corresponding to 1.2%migrations and 1.8%*** the 23cases of migration,1 case did not require adjustment and another underwent unsuccessful *** rate of successful adjustment of migrated catheters was 91.3%,whereas the rate of successful removal of fractured catheters was 100%.No surgery-related complications were observed either immediately or during the 1-month follow-up ***:This study showed that the incidence of abnormal catheter positioning is *** techniques used for the adjustment or removal of abnormally placed catheters are safe,efficient,and minimally invasive.

关键词： Port-a-cath system Tip migration Catheter fracture Intravascular treatment

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偏振光谱成像仪太阳与月球联合在轨标定技术研究

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北京理工大学学报 2023年第4期43卷 394-402页

作者：孔健北京理工大学光电学院精密光电测试仪器及技术北京市重点实验室北京100081

航天遥感器入轨及在轨运行期间,由于重力、应力释放、热以及元器件老化等因素的综合影响需要对其进行在轨标定.为了提高星上辐射标定精度,提出了对月标定和太阳标定相结合的在轨标定方法.通过对月成像实现中心场的在轨绝对辐射标定,标... 详细信息

航天遥感器入轨及在轨运行期间,由于重力、应力释放、热以及元器件老化等因素的综合影响需要对其进行在轨标定.为了提高星上辐射标定精度,提出了对月标定和太阳标定相结合的在轨标定方法.通过对月成像实现中心场的在轨绝对辐射标定,标定仪器辐射特性的星地差异和在轨的变化情况.通过太阳标定获取探测器的非均匀性变化.对偏振光谱成像仪标定不确定度进行了分析,研究结果表明:绝对辐射标定总不确定度为3.77%,满足5%辐射标定精度要求.

关键词：对月标定太阳标定漫反射板制作偏振光谱成像仪

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Complications from port-a-cath system implantation in adults with malignant tumors:A 10-year single-center retrospective study

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Journal of Interventional Medicine 2022年第1期5卷 15-22页

作者： Yong Li jianxi Guo Yanfang Zhang jian kong Department of Interventional Radiology Shenzhen People’s Hospital(Second Clinical Medical College of Jinan UniversityFirst Affiliated Hospital of Southern University of Science and Technology)ShenzhenChina

Background:Port-A-Cath systems(PCS)are safe and convenient devices for long-term infusion in patients with malignant *** study retrospectively analyzed the complications from PCS and their ***:Data of 1695 adults(641 males and 1054 females)with malignant tumors who underwent PCS implantation in our center from January 1,2009 to December 31,2019 who had complete follow-up records were collected in this *** early and late complications and corresponding treatments were ***:A total of 1716 PCSs were implanted;21 patients underwent 2 implantations *** success rate was100%and no severe complications occurred during *** overall occurrence rate of post-implantation complications was 18.5%(318/1716);5.5%(94/1716)were early complications and 13.0%(224/1716)were late complications.A total of 451 PCSs were removed,of which 398 were removed due to the end of chemotherapy,while 53 were removed because of complications.A total of 4 deaths occurred from these ***:The incidence of intra-and post-operative complications is *** most cases,complications can be effectively controlled without the removal of the PCS and regular follow-up and maintenance are critical.

关键词： Port-a-cath system(PCS) Complications Treatments

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Anchoring heterometallic cluster on P-doped carbon nitride for efficient photocatalytic nitrogen fixation in water and air ambient

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Chinese Chemical Letters 2024年第4期35卷 176-180页

作者： Chao-Long Chen Rong Chen La-Sheng Long Lan-Sun Zheng Xiang-jian kong Collaborative Innovation Center of Chemistry for Energy Materials State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Light-driven nitrogen fixation to produce ammonia is a green and economical technology of nitrogen reduction but is still quite challenging, especially in an air atmosphere without any sacrificial ***, we demonstrate efficient photocatalytic nitrogen fixation using water and air directly by loading lanthanide–transition metal(4f–3d) cluster NdCo_(3) on two-dimensional P-doped graphitic carbon nitrides(PCN) material surface. Benefiting from the increase in the number of nitrogen vacancies(NVs) and highly matched band gap structure and excellent hole trapping ability of clusters, the NdCo_(3)/PCN photocatalyst exhibits efficient nitrogen reduction activity with 371(in air) and 825 μmol h^(-1)g^(-1)(in pure nitrogen)without any sacrificial reagents. The introduction of potassium sulfate inhibits hydrogen production and promotes nitrogen reduction activation. This work suggests that anchoring precisely structured clusters on 2D materials may enhance photocatalytic nitrogen reduction under normal temperature and pressure.

关键词： Photocatalytic Nitrogen fixation 4f-3d Cluster Air atmosphere

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