检索结果-内蒙古大学图书馆

A novel copper-sensing two-component system for inducing Dsb gene expression in bacteria

Science Bulletin 2022年第2期67卷 198-212,M0004页

作者： Liang Yu Qiao Cao Weizhong Chen Nana Yang Cai-Guang Yang Quanjiang Ji Min Wu Taeok Bae Lefu Lan University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Department of Biomedical Sciences University of North DakotaGrand Forks ND 58203-9037USA Department of Microbiology and Immunology Indiana University School of Medicine-NorthwestGary IN 46408USA School of Pharmaceutical Science and Technology Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China NMPA Key Laboratory for Testing Technology of Pharmaceutical Microbiology Shanghai Institute for Food and Drug ControlShanghai 201203China

In nature, bacteria must sense copper and tightly regulate gene expression to evade copper toxicity. Here,we identify a new copper-responsive two-component system named DsbRS in the important human pathogen Pseudomonas aeruginosa;in this system, DsbS is a sensor histidine kinase, and DsbR, its cognate response regulator, directly induces the transcription of genes involved in protein disulfide bond formation(Dsb)(i.e., the dsbDEG operon and dsbB). In the absence of copper, DsbS acts as a phosphatase toward DsbR, thus blocking the transcription of Dsb genes. In the presence of copper, the metal ion directly binds to the sensor domain of DsbS, and the Cys82 residue plays a critical role in this process. The copperbinding behavior appears to inhibit the phosphatase activity of DsbS, leading to the activation of *** copper resistance of the dsbRS knock-out mutant is restored by the ectopic expression of the dsbDEG operon, which is a DsbRS major target. Strikingly, cognates of the dsbRS-dsbDEG pair are widely distributed across eubacteria. In addition, a DsbR-binding site, which contains the consensus sequence 5’-TTA-N8-TTAA-3’, is detected in the promoter region of dsbDEG homologs in these species. These findings suggest that the regulation of Dsb genes by DsbRS represents a novel mechanism by which bacterial cells cope with copper stress.

关键词： Pseudomonas aeruginosa Two-component system Disulfide bond formation Gene regulation Copper resistance

来源：评论

学校读者我要写书评

暂无评论

Environmental exposure and ecological risk of perfluorinated substances (PFASs) in the Shaying River Basin, China

引用

Chemosphere 2023年第1期339卷 139537页

作者： Zhang, Ya-Hui Ding, Ting-Ting Huang, Zi-Yan Liang, Hong-Yi Du, Shi-Lin Zhang, Jin Li, Hui-Xian State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing100012 China Environmental Analysis and Testing Laboratory Chinese Research Academy of Environmental Sciences Beijing100012 China Key Laboratory of Yangtze River Water Environment Ministry of Education College of Environmental Science and Engineering Tongji University Shanghai200092 China Hangzhou Yanqu Information Technology Co. Ltd Hangzhou310005 China School of Environmental and Chemical Engineering Yanshan University Qinhuangdao066004 China Key Laboratory of Water Pollution Control and Waste Water Resource of Anhui Province College of Environment and Energy Engineering Anhui Jianzhu University Hefei230601 China

There have been concerns raised about the environmental effects of perfluoroalkyl substances (PFASs) because of their toxicity, widespread distribution, and persistence. Understanding the occurrences and ecological risk posed by PFASs is essential, especially for the short-chain replacements perfluorobutanoic acid (PFBA) and perfluorobutane sulfonic acid (PFBS), which are now becoming predominant PFASs. The lack of aquatic life criteria (ALC), however, prevents an accurate assessment of the ecological risks of PFBA and PFBS. This study thus investigated the occurrence of 15 PFASs at 29 sampling sites in Shaying River Basin (in China) systematically, conducted the toxicity tests of PFBA and PFBS on eight resident aquatic organisms in China, and derived the predicted non-effect concentration (PNEC) values for PFBA and PFBS for two environmental media in China. The results showed that the total PFASs concentrations (ΣPFASs) ranged from 5.07 to 20.32 ng/L (average of 10.95 ng/L) in surface water, whereas in sediment, ΣPFASs ranged from 6.46 to 20.05 ng/g (dw) (average of 11.51 ng/g). The presence of PFBS was the most prominent PFASs in both water (0.372–8.194 ng/L) and sediment (4.54–15.72 ng/g), demonstrating that short-chain substitution effects can be observed in watersheds. The PNEC values for freshwater and sediment were 6.60 mg/L and 8.30 mg/kg (ww), respectively, for PFBA, and 14.04 mg/L, 37.08 mg/kg (ww), respectively, for PFBS. Ecological risk assessment of two long-chain PFASs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), and two short-chain PFASs, PFBA and PFBS, using the hazard quotient method revealed that Shaying River and other major River Basins in China were at risk of PFOS contamination. This study contributes to a better understanding of the presence and risk of PFASs in the Shaying River and first proposes the ALCs for PFBA and PFBS in China, which could provide important reference information for water quality standards. © 202

关键词： Rivers

来源：评论

学校读者我要写书评

暂无评论

Physicochemically protected organic carbon release is the rate-limiting step of rhizosphere priming in paddy soils

引用

Science of the Total Environment 2024年 955卷 176859页

作者： Wu, Cuiyan Huang, Wei Liu, Yixian Li, Han Ding, Shuai Zhu, Zhenke Wang, Feng Dijkstra, Feike A. Zhang, Guangbin Kuzyakov, Yakov Cheng, Weiguo Xiao, Mouliang Ge, Tida School of Materials and Chemical Engineering Ningbo University of Technology Ningbo315211 China State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products Institute of Plant Virology Ningbo University Ningbo315211 China Ningbo Key Laboratory of Testing and Control for Characteristic Agro-Product Quality and Safety Ningbo315211 China Sydney Institute of Agriculture School of Life and Environmental Sciences The University of Sydney CamdenNSW2570 Australia State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing210008 China Department of Soil Science of Temperate Ecosystems Department of Agricultural Soil Science University of Göttingen Göttingen37077 Germany Faculty of Agriculture Yamagata University Yamagata Tsuruoka997-8555 Japan State Key Laboratory of Subtropical Silviculture College of Environment and Resources Zhejiang A&F University Hangzhou311300 China

Iron oxides affect the stability of soil organic matter (SOM), which in turn affects greenhouse gas emissions in paddy soils. They also regulate the direction and magnitude of the rhizosphere priming effect (RPE) by restricting SOM accessibility and microbial activity. However, the controlling steps and key factors that regulate the RPE magnitude under anoxic conditions are unknown. In this study, we investigated the mechanisms through which Fe(III) reduction affects the RPE using humic acid as an electron shuttle in paddy soils and conducting continuous 13CO2 labeling of rice plants. The RPE, measured via CO2 emission, was approximately 25 % greater in soils with humic acid than in soils without. A rapid increase in the RPE of CH4 emissions after 41 days was attenuated in soils containing humic acid. Root growth and Fe(III) reduction stimulated the total primed CO2 emissions from the rhizosphere independent of the microbial biomass and enzyme activities. Humic acid accelerated Fe(III) reduction, leading to a decrease in Fe-bound organic carbon and an increase in RPE (CO2 emissions). The rhizosphere-primed CO2 emissions decreased with increasing amounts of reactive Fe(III) (oxyhydr)oxides, which protected the SOM from microbial and enzymatic attacks. Biochemical Fe(III) reduction and physical aggregate destruction controlled the abiotic transformation of inaccessible SOM into bioavailable organic carbon, thereby regulating the RPE. The results suggest that the reduction of reactive Fe(III) minerals is the rate-limiting step in the release of the physicochemically protected SOM, which in turn determines the magnitude of rhizosphere priming in paddy soils. © 2024 Elsevier B.V.

关键词： Kyoto Protocol

来源：评论

学校读者我要写书评

暂无评论

Research on a Three-phase Flow Electromagnetic Measurement Method

引用

IOP Conference Series: Earth and Environmental Science 2021年第2期692卷

作者： Xuejing Li Haiyang Li Shanghai Institute of Measurement and Testing Technology Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai China

For a long time, industrial and agricultural production has a wide range of requirements for energy saving and emission reduction. The flow parameter detection of water/gas/oil three-phase flow is of great significance in the control and optimization of the petroleum industry process. Using the principle of correlation method, a multi-electrode electromagnetic measurement method is designed to measure the three-phase flow. The system has the function of self-detection of the meter zero point. The finite element method is used to calculate and analyze the distribution of sensitive fields inside the flow measurement sensor and the influence of different physical parameters of non-conductive objects on the disturbance characteristics of the flow measurement sensor. And through experiments to prove the feasibility, stability and accuracy of the constructed measurement system.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Computer transient simulation for dual in-line package through finite element analysis and ANASYS software 3

Computer transient simulation for dual in-line package throu...

引用

3rd International Conference on Electrical, Communication and Computer Engineering, ICECCE 2021

作者： Su, Wei Luo, Wenhao Dong, Xianshan Chen, Si Tomar, Agam Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou China MOE Key Lab of Disaster Forecast and Control in Engineering Guangzhou China School of Mechanics and Construction Engineering Jinan University Guangzhou China Faculty of Engineering and Mathematical Sciences University of Western Australia Australia

The reliability of the DIP package is studied by numerical simulation. Firstly, the DIP package, fixture and metal steel are modeled. Based on this, variable thickness papers are laid on the sample. According to the experiment, corresponding excitation and boundary condition are set. Then, the transient analysis result of DIP package is obtained through numerical simulation. The results show the relation of different thickness papers and acceleration-time curve, which provides a beneficial reference for the optimization of DIP packing. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Transient analysis

来源：评论

学校读者我要写书评

暂无评论

Effects of Different Drying Methods on the Quality Characteristics and Flavor Substances of Morchella Sextelata Mushrooms

SSRN

引用

SSRN 2024年

作者： Liao, Yaxuan Xin, Mengdi Dong, Hao Liu, Yuxing Li, Lingling Guo, Xinyong Cheng, Shaobo Chen, Guogang Shihezi University China College of Food Science and Technology Shihezi University Shihezi832000 China Ministry of Agriculture and Rural Affairs School of Food Science and Technology Shihezi University Xinjiang Shihezi832000 China Key Laboratory for Food Nutrition and Safety Control of Xinjiang Production and Construction Corps School of Food Science and Technology Shihezi University Xinjiang Shihezi832000 China Shihezi Testing Institute of Quality and Metrology Shihezi832000 China College of Life Science Shihezi University Shihezi832000 China

In this study, the effects of hot-air drying (HAD), hot-air combined microwave vacuum drying (HAD-MVD), vacuum freeze drying (VFD), and natural drying (ND) on the color, textural properties, microstructure, non-volatile substances, and volatile flavor compounds of the Morchella sextelata mushroom were investigated, with the aim of optimizing its drying process. The results showed that VFD best maintains the color, texture, and flavor of Morchella, while HAD-MVD yields dehydrated morchella having a color and dense cellular microstructure similar to that achieved with VFD but in less time. In addition, the equivalent umami concentration and total aroma compound content for HAD-MVD were significantly higher than that for VFD, as was the retention rates of non-volatile flavor substances such as total soluble sugars, 5'-nucleotides, and total free amino acids. Therefore, HAD-MVD represents an economic and more environmentally benign solution for the commercial processing of morchella. © 2024, The Authors. All rights reserved.

关键词： Flavor compounds

来源：评论

学校读者我要写书评

暂无评论

Harmonic response analysis for ball grid array package using computer finite element simulation 3

Harmonic response analysis for ball grid array package using...

引用

3rd International Conference on Electrical, Communication and Computer Engineering, ICECCE 2021

BGA package is selected as the research object in this paper. Workbench (finite elemental analysis tool in ANSYS) is used for harmonic response analysis. The author lays several paper sheets on the sample and builds the finite element model of clamp, ceramic and metal plate. Then, the model analysis is carried out. Based on this, it is converted to harmonic response analysis. According to the results, the author has found that there is no relation between the number of paper sheets and acceleration-frequency result. It promotes the development of electronic packaging reliability. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Finite element method

来源：评论

学校读者我要写书评

暂无评论

Effects of Water Vapor on Adsorption Performance of Activated Carbon for Methyl Mercaptan, Toluene and N-Hexane in Fermentation Industrial Waste Gas

SSRN

引用

SSRN 2022年

作者： Yao, Xiaolong Shi, Yue Zhou, Jingya Yao, Zhiliang Li, Changmin He, Li Gong, Wenwen School of Ecology and Environment Beijing Technology and Business University Beijing100048 China State Environmental Protection Key Laboratory of Food Chain Pollution Control Beijing Technology and Business University Beijing100048 China Institute of Quality Standard and Testing Technology Beijing Academy of Agriculture and Forestry Science Beijing100097 China

Excessive water vapor in fermentation industrial waste gas complicates the competitive adsorption between water vapor and multicomponent VOCs gases. It is necessary to make an in-depth study on the water vapor-multicomponent VOCs adsorption process on the surface of activated carbon. In this study, a starch-based activated carbon with highly developed microporous structure and rich in oxygen- and nitrogen-containing functional groups was used as the adsorbent. Mixture of three typical VOCs methyl mercaptan, toluene and n-hexane generated in fermentation industrial waste gas was selected as the adsorbate. The adsorption experiments and molecular simulation were used to focus on the adsorption behavior and mechanisms of water vapor and multicomponent VOCs gas on the porous carbon interface. The results indicate that the adsorption energy between water molecules and activated carbon is stronger than that between VOCs and activated carbon. Therefore, toluene, n-hexane and methyl mercaptan are replaced by water molecules at relative humidity 30%. At relative humidity 70%, a water film is formed by capillary condensation on the surface of activated carbon, it reduces the adsorption selectivity of activated carbon for toluene and n-hexane but increases the adsorption selectivity for methyl mercaptan. The water film prevents the adsorption of n-hexane and toluene on the surface of the adsorbent. However, methyl mercaptan can be dissolved in the water film to maintain a relatively stable sorption quantity. Its adsorption changes from the oxidation of oxygen-containing substances on the surface of the adsorbent at relative humidity 0% to the dissolution effect in the water film. © 2022, The Authors. All rights reserved.

关键词： Fermentation

来源：评论

学校读者我要写书评

暂无评论

Stable isotope and elemental profiles determine geographical origin of saffron from China and Iran

引用

Food Chemistry 2023年第PartA期405卷 134733页

作者： Nie, Jing Yang, Jian Liu, Cuiling Li, Chunlin Shao, Shengzhi Yao, Chunxia Chen, Bilian Tao, Yi Wang, Fang Zhang, Yongzhi Rogers, Karyne M. Wang, Ping Yuan, Yuwei State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products Hangzhou310021 China State Key Laboratory of Dao-di Herbs Breeding Base National Resource Center for Chinese Materia Medica China Academy of Chinese Medical Sciences Beijing100700 China Beijing Key Laboratory of Big Data Technology for Food Safety Beijing Technology and Business University Beijing100048 China Institute of Agro-Products Safety and Nutrition Zhejiang Academy of Agricultural Sciences Key Laboratory of Information Traceability for Agricultural Products Ministry of Agriculture and Rural Affairs of China Hangzhou310021 China Institute for Agro-food Standards and Testing Technology Shanghai Academy of Agricultural Sciences Shanghai201403 China Zhejiang Institute for Food and Drug Control Hangzhou310052 China College of Pharmaceutical Sciences Zhejiang University of Technology Hangzhou310014 China National Isotope Centre GNS Science Lower Hutt5040 New Zealand

Origin verification of high-value saffron is essential for fair trade and to protect consumers' interests and rights. A traceability method using elemental content (% C and % N) and stable isotopes (δ13C, δ2H, δ18O, and δ15N) combined with chemometrics was developed to discriminate saffron from Iran and China and classify major domestic production areas in China. Results showed that Iranian samples had lower % C and % N contents but higher δ13C values than Chinese origin saffron, with δ13C acting as an important variable for origin discrimination. Moreover, δ2H and δ13C isotopes were found to be important variables to classify Chinese regional saffron origin. Two supervised pattern recognition models (PLS-DA) developed to classify Iranian and Chinese saffron, and regional Chinese saffron had a discrimination accuracy of 85.0 % and 80.2 %, respectively. These models provide the basis for a new regulatory inspection procedure to verify saffron origin and label claims, minimizing fraudulent mislabeling and adding value to saffron from specific regions. © 2022 Elsevier Ltd

关键词： Pattern recognition

来源：评论

学校读者我要写书评

暂无评论

Preparation of CoFe2O4 and its peroxymonosulfate activation for degradation of sulfamethoxazole

引用

Jingxi Huagong/Fine Chemicals 2022年第5期39卷 1020-1027页

作者： Li, Yinghao Zheng, Xiangqian Gao, Xiaoya Zhu, Wenjie Luo, Yongming Lu, Jichang Faculty of Environmental Science and Engineering Kunming University of Science and Technology Kunming650500 China Faculty of Chemical Engineering Kunming University of Science and Technology Kunming650500 China Xishuangbanna Prefecture Comprehensive Testing Center for Quality and Technical Supervision Jinghong666100 China Key Laboratory for Odorous Volatile Organic Compounds Pollutants Control of Yunnan Province Colleges and Universities Kunming650500 China

Using cobalt nitrate hexahydrate and ferrous sulfate heptahydrate as raw materials, a series of cobalt ferrite materials (CoFe2O4-X, X represents calcination temperature, which are 450, 550 and 650 ℃, respectively) were successfully synthesized by a simple co-precipitation method. They were characterized by SEM, XRD, BET and XPS, and used for activation peroxymonosulfate (PMS) to degrade sulfamethoxazole (SMX). The effects of catalyst dosage, PMS dosage, pH, inorganic ion species and reaction temperature on the degradation of SMX were investigated. The results showed that CoFe2O4-550 exhibited the best catalytic performance. Under the optimal reaction conditions (SMX initial mass concentration of 10 mg/L, CoFe2O4-550 dosage of 0.3 g/L and PMS mass concentration of 1.5 g/L), the degradation rate of SMX could reach 95% within 20 min and total organic carbon (TOC) removal rate was 80%. At the same time, CoFe2O4-550/PMS reaction system had excellent catalytic performance at a wide pH range (pH=5~9). CoFe2O4-550 could be recovered magnetically, and the removal rate of SMX could still reach 83% after three reaction cycles, indicating that CoFe2O4-550 had good stability and reusability. A large amount of SO4-• and •OH radicals were produced during the degradation reaction, and the corresponding catalytic degradation mechanism was proposed. © 2022, Editorial Office of FINE CHEMICALS. All right reserved.

关键词： Degradation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：