Production of a Recombinant Laccase from Pichia pastoris and Biodegradation of Chlorpyrifos in a Laccase/Vanillin System

( Hui fang Xie ),( Qi Li ),( Min Min Wang ),( Lin Guo Zhao ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.6

The recombinant strain P. pastoris GS115-lccC was used to produce laccase with high activity. Factors influencing laccase expression, such as pH, methanol concentration, copper concentration, peptone concentration, shaker rotate speed, and medium volume were investigated. Under the optimal conditions, laccase activity reached 12,344 U/L on day 15. The recombinant enzyme was purified by precipitating and dialyzing to electrophoretic homogeneity, and was estimated to have a molecular mass of about 58 kDa. When guaiacol was the substrate, the laccase showed the highest activity at pH 5.0 and was stable when the pH was 4.5~6.0. The optimal temperature for the laccase to oxidize guaiacol was 60℃, but it was not stable at high temperature. The enzyme could remain stable at 30℃ for 5 days. The recombinant laccase was used to degrade chlorpyrifos in several laccase/mediator systems. Among three synthetic mediators (ABTS, HBT, VA) and three natural mediators (vanillin, 2,6-DMP, and guaiacol), vanillin showed the most enhancement on degradation of chlorpyrifos. Both laccase and vanillin were responsible for the degradation of chlorpyrifos. A higher dosage of vanillin may promote a higher level of degradation of chlorpyrifos, and the 2-step addition of vanillin led to 98% chlorpyrifos degradation. The degradation of chlorpyrifos was faster in the L/V system (kobs = 0.151) than that in the buffer solution (kobs = 0.028).

ACOS5 is Required for Primexine Formation and Exine Pattern Formation During Microsporogenesis in Arabidopsis

Hui-hui Xie,Lin Chen,Fa-qing Xu,Wan-sheng Guo,Shui Wang,Zhong-Nan Yang,Sen Zhang 한국식물학회 2017 Journal of Plant Biology Vol.60 No.4

Pollen exine, mainly composed of sporopollenin,plays important roles during microspore development. It hasbeen reported that Acyl-CoA Synthetase5 (ACOS5) is requiredfor sporopollenin biosynthesis in Arabidopsis. Here we showthat ACOS5 is essential for primexine formation duringArabidopsis microspore development. Through genetic screen,we identified a point mutation of ACOS5 allele, acos5-2,showing abnormal microspore development. Its microsporeswere degenerated and aborted after released from the tetrads. Transmission electron microscopy showed that primexineformation was reduced in acos5-2 mutant as compared tothat of the wild-type. Consequently, sporopollenin wasaggregated and randomly deposited on the microspores. Insitu hybridization indicated that the key regulators of tapetumdevelopment, DYT1 and TDF1, are required for the expressionof ACOS5 in tapetum. Furthermore, the GUS reporter showedthat the 593-bp promoter sequence was sufficient for theexpression of ACOS5 in the anther. Our data provide evidencethat ACOS5 is required for primexine formation andsporopollenin deposition during microspore development.

Effect of Global Warming on Chloride Ion Erosion Risks for Offshore RC Bridges in China

Hui-bing Xie,Yuan-Feng Wang,Jian Gong,Ming-hui Liu,Xiao-Yuan Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.9

Chloride ion penetration, which leads to corrosion of steel reinforcement, is the leading cause of offshore reinforced concrete bridge deterioration. Global warming would accelerate the process of chloride ion penetration and then structural degradation. In China, durability design code for concrete structures has been issued in 2008, and some thresholds of design parameters have been specified to mitigate corrosion in concrete bridge. However, influence of global warming on structure durability was not considered in the issued code. This would overestimate the durability of concrete structures. In this paper, a reliability based method was adopted to evaluate the influence of climate change on the durability of offshore RC bridges considering the acceleration of chloride ion penetration caused by temperature rise. Two climate change scenarios according to IPCC report were considered to define the global warming. A baseline scenario, in which the mean average temperature equals to that of the year 2000, were defined. It is found that the amount of chloride ion on the surface of reinforcing steel bar in the global warming scenarios are 6%-15% higher than that of structure in the baseline scenario. Meanwhile, the probability of corrosion initiation and corrosion damage increased also. In 2100, structures in environmental categories III-C and III-F, designed according to Chinese codes, can no longer adapt the impact of climate change on structure. Comparison of reliability of improved and pre-improved structure was conducted to verify the effectiveness of the proposed improvement measures.

Research Articles : Genetic analysis of the related traits of flowering and silk for hybrid seed production in maize

( Hui Ling Xie ),( Dong Ding ),( ZI Tian Cui ),( Xin Wu ),( Yan Min Hu ),( Zong Hua Liu ),( Yu Ling Li ),( Ji Hua Tang ) 한국유전학회 2010 Genes & Genomics Vol.32 No.1

Similarity of User Ratings Play a Positive Information Filter in Social Networks

Hui Xie,Jianfeng Ma,Lin Yang 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.9

In the past decade, social recommending systems have attracted increasing attention from the physical, social and computer science communities. In this study, we use social networks to capture similarities of users’ interest and, accordingly, recommending systems to explore latent similarities. We build similarity-ratings-prediction models for a dataset of books and reviewers from Douban.com. The similarities are measured by the Pearson and the Jaccard correlation coefficients. Using singular value decomposition, we evaluate the strengths and the weaknesses of the similarity measure, and discuss their effectiveness in recommending systems.

Research on the Technique of End-hopping Based Upon Clock-controlled Nonlinear Sequence

Xie Hui,Li Jing,Zhoh Yi-lei 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.2

Community detection based on BernNet graph convolutional neural network

Xie Hui,Ning Yixin 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.5

As an important part of network analysis, community detection has attracted extensive attention of researchers in various felds. Using Graph Neural Network (GNN) model to solve the problem of community detection is a new direction of community detection research. BernNet is a graph convolutional neural network based on Bernstein polynomial approximation of order K, which can be used to design arbitrary flters, but it is slow because of its quadratic dependence on K. In this paper, a novel algorithm using frst-order Bernstein polynomial is proposed: (i) approximate the defnition of flters, takes the original labels of data as the basis for community division; (ii) defnes the loss function between the labels predicted by the algorithm and the original data labels, (iii) acquires the probability model of node labels predicted by the node characteristic matrix with the smallest loss function through backpropagation. The results of community segmentation are evaluated using Normalized Mutual Information (NMI). Compared with the state-of-the-art methods, the experimental results show that: the algorithm can achieve better community detection results on real data sets and reduce the complexity of the algorithm while obtaining better results.

Universally Composable Attribute-based Group Key Exchange

Hui Xie,Yongjie Yan,Sihui Shu 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.1

Several protocols implementing attribute-based group key exchange, which allows users with certain set of attributes to establish a session key, have been proposed in recent years. However, attacks on attribute-based group key exchange in current research have been considered only in stand-alone fashion. Thus these protocols may be vulnerable when run with other protocol sessions concurrently. We treat the security of attribute-based group key exchange in the universal composability framework to ensure that a protocol remains secure when run with arbitrary protocol sessions concurrently. More specifically, we define an ideal functionality for attribute-based group key exchange first, then propose a two-round protocol based on a primitive called encapsulation policy attribute-based key encapsulation mechanism. In addition, a complete security proof of our protocol in the universal composability framework under random oracle model is given.

Dynamical Behavior of Rumor in Online Social Networks

Hui Xie,Yongjie Yan,Yingchun Hou 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.3

As a powerful tool for phase transition analysis, the mean-field theory of rumor spreading brings us a new method for research in Online Social Networks (OSN). Based on the theory of complex networks, we simulate the complex process of rumor spreading in OSN. Using numerical simulations with focus on the information spreading threshold as well as critical behaviors, we study the Susceptible-Infected-Recovered- Susceptible (SIRS) information dynamics model in OSN with asymmetric propagation. Basic principle and structure of OSN were analyzed. We present a rumor spreading model, where the influence of the neighbor trees is treated in a more realistic way and the definition of a neighborhood can be tuned by an additional parameter. Based on the mean-field theory approach, a contact network model with scale-free property is built. It is demonstrated that the asymmetry of propagation plays important role: we could redistribute the asymmetry to balance the degree heterogeneity of the network and then to restore the information threshold to a finite value. The relationship of spreading probability, network size, infected fraction and infected ratio are showed respectively in the paper. Our model exhibits a surprisingly sharp phase transition which can be shifted by a redefinition of the neighborhood. The result shows that the SIRS model built in this paper is valid and the simulation of the information propagation is feasible.

Detecting an Overlapping Community Structure by Using Clique-to-Clique Similarity based Label Propagation

Hui Xie,Yongjie Yan 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.6

Many researchers have proven that complex networks have community structures and that most network communities are overlapping. Numerous algorithms have been proposed and used to detect non-overlapping or overlapping communities in networks. Many community-detecting algorithms are based on a clique. A clique is a subset of the nodes in the network in which every pair of nodes has an edge between them. In this paper, we propose a new algorithm that is based on a clique-to-clique similarity measure, and the label propagation to detect overlapping communities. The algorithm first finds all cliques of the network; then, it builds a new network according to a specific strategy, that specifies that in the new network, a node represents a clique found in the last step, and an edge is the link relation generated according to the strategy. The experimental results for both synthetic networks and real-world networks show that the proposed algorithm is not only effective, but also better than other algorithms in forms of the quality of results on the time efficiency.