Cloning and Functional Characterization of Putative Escherichia coli ABC Multidrug Efflux Transporter YddA

( Zhenyue Feng ),( Defu Liu ),( Ziwen Liu ),( Yimin Liang ),( Yanhong Wang ),( Qingpeng Liu ),( Zhenhua Liu ),( Zhongjing Zang ),( Yudong Cui ) 한국미생물 · 생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.7

A putative multidrug efflux gene, yddA, was cloned from the Escherichia coli K-12 strain. A drugsensitive strain of E. coli missing the main multidrug efflux pump AcrB was constructed as a host and the yddA gene was knocked out in wild-type (WT) and drug-sensitive E. coliΔacrB to study the yddA function. Sensitivity to different substrates of WT E.coli, E. coliΔyddA, E. coliΔacrB and E. coliΔacrBΔyddA strains was compared with minimal inhibitory concentration (MIC) assays and fluorescence tests. MIC assay and fluorescence test results showed that YddA protein was a multidrug efflux pump that exported multiple substrates. Three inhibitors, ortho-vanadate, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and reserpine, were used in fluorescence tests. Ortho-vanadate and reserpine significantly inhibited the efflux and increased accumulation of ethidium bromide and norfloxacin, while CCCP had no significant effect on YddA-regulated efflux. The results indicated that YddA relies on energy released from ATP hydrolysis to transfer the substrates and YddA is an ABC-type multidrug exporter. Functional study of unknown ATP-binding cassette (ABC) superfamily transporters in the model organism E. coli is conducive to discovering new multidrug resistance-reversal targets and providing references for studying other ABC proteins of unknown function.

A SIMULATION STUDY ON THE PROCESS OF NICKEL FILLING INTO CARBON NANOTUBES

LIU BAI,LIU LIRUI,ZHAO ZHENYU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.8

Carbon Nanotubes (CNTs) filled with metals can be used in capacitors, sensors, rechargeable batteries and so on. In this study, the process of Nickel filling into single wall CNTs was studied by molecular dynamics (MD) simulation. Three models consisting of Nickel atoms and CNTs were established. These models were cooled from 1500 K to 100 K to analyze the factors that infuence the filling height, such as temperature, the force between Carbon and Nickel atoms, as well as CNTs diameter. The results showed that filling height increased as the temperature and the force between Carbon–Nickel atoms rised. Filling height reduced with the increasing diameter of CNTs.

Isogeometric analysis of functionally graded CNT-reinforced composite plates based on refined plate theory

Zhenyu Liu,Chuang Wang,Guifang Duan,Jianrong Tan 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9

A simple and effective approach based on refined plate theory (RPT) is proposed to study the static and free vibration characteristics of functionally graded CNTreinforced composite (FG-CNTRC) plates. Compared to traditional higher order shear deformation theories (HSDTs), the proposed method shows more efficient for FG-CNTRC plates analysis. To solve the C1-continuity requirement of the RPT, we used isogeometric analysis (IGA) to approximate the displacement field, which shows more advantages than the FEA, since it can construct higher-order elements without additional variables. This is an advantage for plate structural analysis because more variables make the calculation cumbersome. Finally, four types of FG-CNTRC plates were investigated and the results show the accuracy and efficiency of the proposed method.

Hair follicle development and related gene and protein expression of skins in Rex rabbits during the first 8 weeks of life

Zhenyu Wu,Liangzhan Sun,Gongyan Liu,Hongli Liu,Hanzhong Liu,Zhiju Yu,Shuang Xu,Fuchang Li,Yingbe Qin 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.4

Objective: We aimed to observe hair follicle (HF) development in the dorsal skin and elucidate the expression patterns of genes and proteins related to skin and HF development in Rex rabbits from birth to 8 weeks of age. Methods: Whole-skin samples were obtained from the backs of Rex rabbits at 0, 2, 4, 6, and 8 weeks of age, the morphological development of primary and secondary HFs was observed, and the gene transcript levels of insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF), bone morphogenetic protein 2 (BMP2), transforming growth factor β-1, 2, and 3 (TGFβ-1, TGFβ-2, and TGFβ-3) were examined using quantitative real-time polymerase chain reaction (PCR). Additionally, Wnt family member 10b (Wnt10b) and β-Catenin gene and protein expression were examined by quantitative real-time PCR and western blot, respectively. Results: The results showed significant changes in the differentiation of primary and secondary HFs in Rex rabbits during their first 8 weeks of life. The IGF-I, EGF, TGFβ-2, and TGFβ-3 transcript levels in the rabbits were significantly lower at 2 weeks of age than at birth and gradually increased thereafter, while the BMP2 and TGFβ-1 transcript levels at 2 weeks of age were significantly higher than those at birth and gradually decreased thereafter. β-Catenin gene expression was also significantly affected by age, while the Wnt10b transcript level was not. However, the Wnt10b and β-catenin protein expression levels were the lowest at 2 and 4 weeks of age. Conclusion: Our data showed that a series of changes in HFs in dorsal skin occurred during the first 8 weeks. Many genes, such as IGF-I, EGF, BMP2, TGFβ-1, TGFβ-2, TGFβ-3, and β-Catenin, participated in this process, and the related proteins Wnt10b and β-Catenin in skin were also affected by age.

E-Commerce Consumer Behavior Information Big Data Mining

Liu Hongyan,Liu Zhenyu 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.7

Localized reliability analysis on a large-span rigid frame bridge based on monitored strains from the long-term SHM system

Liu, Zejia,Li, Yinghua,Tang, Liqun,Liu, Yiping,Jiang, Zhenyu,Fang, Daining Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.14 No.2

With more and more built long-term structural health monitoring (SHM) systems, it has been considered to apply monitored data to learn the reliability of bridges. In this paper, based on a long-term SHM system, especially in which the sensors were embedded from the beginning of the construction of the bridge, a method to calculate the localized reliability around an embedded sensor is recommended and implemented. In the reliability analysis, the probability distribution of loading can be the statistics of stress transferred from the monitored strain which covered the effects of both the live and dead loads directly, and it means that the mean value and deviation of loads are fully derived from the monitored data. The probability distribution of resistance may be the statistics of strength of the material of the bridge accordingly. With five years' monitored strains, the localized reliabilities around the monitoring sensors of a bridge were computed by the method. Further, the monitored stresses are classified into two time segments in one year period to count the loading probability distribution according to the local climate conditions, which helps us to learn the reliability in different time segments and their evolvement trends. The results show that reliabilities and their evolvement trends in different parts of the bridge are different though they are all reliable yet. The method recommended in this paper is feasible to learn the localized reliabilities revealed from monitored data of a long-term SHM system of bridges, which would help bridge engineers and managers to decide a bridge inspection or maintenance strategy.

Research on Aggregation and Propagation of Self-Similar Traffic in Satellite Network

Zhenyu Na,Yi Liu,Yang Cui,Qing Guo 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.1

It has already been confirmed that the traffic in high-speed terrestrial network presents self-similarity, but there is little research on self-similarity of traffic in satellite network. Considering time-varying network topology and link status, this paper analyzes the aggregation and propagation of self-similar traffic between nodes in satellite network. Furthermore, a sort of special network node called ground gateway is modeled, based on which the characteristics of the output traffic that the input traffic from terrestrial network passes gateway into satellite network are analyzed. Theoretically analyses demonstrate that after aggregation and propagation between satellite nodes, traffic is still self-similar, and the self-similarity of the output traffic generated by gateway from terrestrial network to satellite network is more often than not weakened.

Research on GUI-based Automation Test Technology Driven by Separated Definition Data

Zhenyu Liu,Qiang Chen,Lizhi Cai 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.6

Abnormal Condition Identification for the Electro-fused Magnesia Smelting Process Based on Condition-relevant Information

Yan Liu,Fuli Wang,Yulu Xiong,Zhenyu Liu,Ruicheng Ma,Fei Chu 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.3

To improve the accuracy of feature representation and abnormal condition identification, a new abnormal condition identification method, named integrating multiple binary neural networks based on condition-relevantinformation (CRI-MBNN), is presented for the electro-fused magnesia smelting process in this study. Firstly, thefeatures related to each specific abnormal condition, which is named condition-relevant information (CRI), are analyzed and extracted from the multi-source heterogeneous information with the help of limited and consensus domainknowledge. Then, the CRI is fused at the feature-level to provide a comprehensive representation of each abnormalcondition. Furthermore, for each abnormal condition, a binary neural network (BNN) is established based on thefused feature. They are further integrated according to the frequency of each condition in the actual productionprocess to form the final abnormal condition identification network, i.e., CRI-MBNN. Finally, the effectiveness andfeasibility of the proposed CRI-MBNN are verified by the electro-fused magnesia smelting process.

Localized reliability analysis on a large-span rigid frame bridge based on monitored strains from the long-term SHM system

Zejia Liu,Liqun Tang,Yinghua Li,Yiping Liu,Zhenyu Jiang,Daining Fang 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.14 No.2

With more and more built long-term structural health monitoring (SHM) systems, it has been considered to apply monitored data to learn the reliability of bridges. In this paper, based on a long-term SHM system, especially in which the sensors were embedded from the beginning of the construction of the bridge, a method to calculate the localized reliability around an embedded sensor is recommended and implemented. In the reliability analysis, the probability distribution of loading can be the statistics of stress transferred from the monitored strain which covered the effects of both the live and dead loads directly, and it means that the mean value and deviation of loads are fully derived from the monitored data. The probability distribution of resistance may be the statistics of strength of the material of the bridge accordingly. With five years\' monitored strains, the localized reliabilities around the monitoring sensors of a bridge were computed by the method. Further, the monitored stresses are classified into two time segments in one year period to count the loading probability distribution according to the local climate conditions, which helps us to learn the reliability in different time segments and their evolvement trends. The results show that reliabilities and their evolvement trends in different parts of the bridge are different though they are all reliable yet. The method recommended in this paper is feasible to learn the localized reliabilities revealed from monitored data of a long-term SHM system of bridges, which would help bridge engineers and managers to decide a bridge inspection or maintenance strategy