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Expression and Characterization of RNA-dependent RNA Polymerase of Dendrolimus punctatus Tetravirus

  • Zhou, Liang;Zhang, Jiamin;Wang, Xiaochun;Jiang, Hong;Yi, Fuming;Hu, Yuanyang
    • BMB Reports
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    • v.39 no.5
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    • pp.571-577
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    • 2006
  • Dendrolimus punctatus tetravirus (DpTV) has been identified as a new member of the genus Omegatetravirus of the family Tetraviridae that may be related serologically to Nudaurelia capensis virus ($N{\omega}V$). To establish the function of DpTV RNA genome and to better understand the mechanism of viral replication, the putative RNA-dependent RNA polymerase (RdRp) domain has been cloned and expressed in Escherichia coli. The recombinant protein was purified on a Ni-chelating HisTrap affinity column and demonstrated to initiate viral RNA synthesis in a primer-independent manner but not by terminal nucleotidyle transferase activity in the presence of $Mg^{2+}$ and RNA template. Mutation of the GDD to GAA interferes with the residues at the polymerase active site and metal ions, and thus renders the polymerase inactive.

Rational Introduction of Disulfide Bond to Enhance Optimal Temperature of Lipomyces starkeyi $\alpha$-Dextranase Expressed in Pichia pastoris

  • Chen, Lin;Yu, Chao;Zhou, Xiangshan;Zhang, Yuanxing
    • Journal of Microbiology and Biotechnology
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    • v.19 no.12
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    • pp.1506-1513
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    • 2009
  • $\alpha$-Dextranase, which can hydrolyze dextran, is largely used in the sugar industry. However, a thermostable $\alpha$-dextranase is needed to alleviate the viscosity of syrups and clean blocked machines. Thus, to improve the optimal temperature of Lipomyces starkeyi $\alpha$-dextranase expressed by Pichia pastoris, the rational introduction of a de novo designed disulfide bond was investigated. Based on the known structure of Penicillium minioluteum dextranase, L. starkeyi $\alpha$-dextranase was constructed using homology modeling. Four amino acids residues were then selected for site-directed mutagenesis to cysteine. When compared with the wild-type dextranase, the mutant DexM2 (D279C/S289C) showed a more than $13^{\circ}C$ improvement on its optimal temperature. DexM2 and DexM12 (T245C/N248C, D279C/S289C) also showed a better thermal stability than the wild-type dextranase. After the introduction of two disulfide bonds, the specific activity of DexM12 was evaluated and found to be two times higher than that of the wild-type. Moreover, DexM12 also showed the highest $V_{max}$.

Association of a miR-502-Binding Site Single Nucleotide Polymorphism in the 3'-Untranslated Region of SET8 and the TP53 Codon 72 Polymorphism with Cervical Cancer in the Chinese Population

  • Yang, Shao-Di;Cai, Yan-Lin;Jiang, Pei;Li, Wen;Tang, Jian-Xin
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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    • pp.6505-6510
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    • 2014
  • Objective: This study was conducted to identify whether polymorphic variants of set domain-containing protein 8 (SET8) and tumor protein p53 (TP53) codon 72, either independently or jointly, might be associated with increased risk for cervical cancer. Methods: We genotyped SET8 and TP53 codon 72 polymorphisms of peripheral blood DNA from 114 cervical cancer patients and 200 controls using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct DNA sequencing. Results: The frequency of SET8 CC (odds ratios (OR) = 2.717, 95% CI=1.436-5.141) or TP53 GG (OR=2.168, 95% CI=1.149-4.089) genotype was associated with an increased risk of cervical cancer on comparison with the SET8 TT or TP53 CC genotypes, respectively. In additional, interaction between the SET8 and TP53 polymorphisms increased the risk of cervical cancer in a synergistic manner, with the OR being 9.913 (95% CI=2.028-48.459) for subjects carrying both SET8 CC and TP53 GG genotypes. Conclusion: These data suggest that there are significant associations between the miR-502-binding site SNP in the 3'-UTR of SET8 and the TP53 codon 72 polymorphism with cervical cancer in Chinese, and there is a gene-gene interaction.

A Modified Quantum Dot-Based Dot Blot Assay for Rapid Detection of Fish Pathogen Vibrio anguillarum

  • Zhang, Yang;Xiao, Jingfan;Wang, Qiyao;Zhang, Yuanxing
    • Journal of Microbiology and Biotechnology
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    • v.26 no.8
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    • pp.1457-1463
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    • 2016
  • Vibrio anguillarum, a devastating pathogen causing vibriosis among marine fish, is prevailing in worldwide fishery industries and accounts for grievous economic losses. Therefore, a rapid on-site detection and diagnostic technique for this pathogen is in urgent need. In this study, two mouse monoclonal antibodies (MAbs) against V. anguillarum, 6B3-C5 and 8G3-B5, were generated by using hybridoma technology and their isotypes were characterized. MAb 6B3-C5 was chosen as the detector antibody and conjugated with quantum dots. Based on MAb 6B3-C5 labeled with quantum dots, a modified dot blot assay was developed for the on-site determination of V. anguillarum. It was found that the method had no cross-reactivity with other than V. anguillarum bacteria. The detection limit (LOD) for V. anguillarum was 1 × 103 CFU/ml in cultured bacterial suspension samples, which was a 100-fold higher sensitivity than the reported colloidal gold immunochromatographic test strip. When V. anguillarum was mixed with turbot tissue homogenates, the LOD was 1 × 103 CFU/ml, suggesting that tissue homogenates did not influence the detection capabilities. Preenrichment with the tissue homogenates for 12 h could raise the LOD up to 1 × 102 CFU/ml, confirming the reliability of the method.

Effect of relative stiffness on seismic response of subway station buried in layered soft soil foundation

  • Min-Zhe Xu;Zhen-Dong Cui;Li Yuan
    • Geomechanics and Engineering
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    • v.36 no.2
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    • pp.167-181
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    • 2024
  • The soil-structure relative stiffness is a key factor affecting the seismic response of underground structures. It is of great significance to study the soil-structure relative stiffness for the soil-structure interaction and the seismic disaster reduction of subway stations. In this paper, the dynamic shear modulus ratio and damping ratio of an inhomogeneous soft soil site under different buried depths which were obtained by a one-dimensional equivalent linearization site response analysis were used as the input parameters in a 2D finite element model. A visco-elasto-plastic constitutive model based on the Mohr-Coulomb shear failure criterion combined with stiffness degradation was used to describe the plastic behavior of soil. The damage plasticity model was used to simulate the plastic behavior of concrete. The horizontal and vertical relative stiffness ratios of soil and structure were defined to study the influence of relative stiffness on the seismic response of subway stations in inhomogeneous soft soil. It is found that the compression damage to the middle columns of a subway station with a higher relative stiffness ratio is more serious while the tensile damage is slighter under the same earthquake motion. The relative stiffness has a significant influence on ground surface deformation, ground acceleration, and station structure deformation. However, the effect of the relative stiffness on the deformation of the bottom slab of the subway station is small. The research results can provide a reference for seismic fortification of subway stations in the soft soil area.

Expression characterization and transcription regulation analysis of porcine Yip1 domain family member 3 gene

  • Ni, Dongjiao;Huang, Xiang;Wang, Zhibo;Deng, Lin;Zeng, Li;Zhang, Yiwei;Lu, Dongdong;Zou, Xinhua
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.3
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    • pp.398-407
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    • 2020
  • Objective: The Yip1 domain family (YIPF) proteins were proposed to function in endoplasmic reticulum (ER) to Golgi transport and maintenance of the morphology of the Golgi, which were homologues of yeast Yip1p and Yif1p. YIPF3, the member 3 of YIPF family was a homolog of Yif1p. The aim of present study was to investigate the expression and regulation mechanism of porcine YIPF3. Methods: Quantitative realtime polymerase chain reaction (qPCR) was used to analyze porcine YIPF3 mRNA expression pattern in different tissues and pig kidney epithelial (PK15) cells stimulated by polyinosine-polycytidylic acid (poly [I:C]). Site-directed mutations combined with dual luciferase reporter assays and electrophoretic mobility shift assay (EMSA) were employed to reveal transcription regulation mechanism of porcine YIPF3. Results: Results showed that the mRNA of porcine YIPF3 (pYIPF3) was widely expressed with the highest levels in lymph and lung followed by spleen and liver, while weak in heart and skeletal muscle. Subcellular localization results indicated that it expressed in Golgi apparatus and plasma membranes. Upon stimulation with poly (I:C), the level of this gene was dramatically up-regulated in a time- and concentration-dependent manner. pYIPF3 core promoter region harbored three cis-acting elements which were bound by ETS proto-oncogene 2 (ETS2), zinc finger and BTB domain containing 4 (ZBTB4), and zinc finger and BTB domain containing 14 (ZBTB14), respectively. In which, ETS2 and ZBTB4 both promoted pYIPF3 transcription activity while ZBTB14 inhibited it, and these three transcription factors all played important regulation roles in tumorigenesis and apoptosis. Conclusion: The pYIPF3 mRNA expression was regulated by ETS2, ZBTB4, and ZBTB14, and its higher expression in immune organs might contribute to enhancing ER to Golgi transport of proteins, thus adapting to the immune response.

Relative strength of 5' splice-site strength defines functions of SRSF2 and SRSF6 in alternative splicing of Bcl-x pre-mRNA

  • Choi, Namjeong;Liu, Yongchao;Oh, Jagyeong;Ha, Jiyeon;Ghigna, Claudia;Zheng, Xuexiu;Shen, Haihong
    • BMB Reports
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    • v.54 no.3
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    • pp.176-181
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    • 2021
  • Bcl-x, a member of the Bcl-2 family, plays a key role in apoptosis. Alternative splicing of Bcl-x pre-mRNA through alternative 5' splice-site selection produces an anti-apoptotic mRNA isoform that includes exon 2b and a pro-apoptotic Bcl-x mRNA isoform that excludes exon 2b. Here we used Bcl-x minigene and identified SRSF2 and SRSF6 as two regulatory factors of 5' splice-site selection of Bcl-x pre-mRNA. We selected binding clusters closer to 5' splice-sites from multiple potential binding sites of SRSF2 and SRSF6 to perform loss of functions analysis through site-directed mutagenesis. Our results demonstrated that these mutations did not abolish regulatory functions of SRSF2 or SRSF6, indicating that a single binding motif or a cluster was not a functional target of these proteins in Bcl-x pre-mRNA splicing. Random deletion mutagenesis did not disrupt the role of SRSF2 and SRSF6. Importantly, mutagenesis of 5' splice-site to a conserved or a weaker score demonstrated that the weaker strength of the target 5' splice-site or higher strength of the other 5' splice-site strength limited the role of SRSF2 and SRSF6 in 5' splice-site activation.

Deriving Critical Management Factors based on Case Studies of Multi-trade MEP Ceiling Rack Prefabrication (복합공종 MEP 천정 선조립 공법 사례조사를 통한 단계별 중점관리사항 도출)

  • Lee, Dongmin;Jang, Sejun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.11a
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    • pp.76-77
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    • 2015
  • In construction industry, management of construction factors such as cost, schedule, quality and safety is the most important key for delivering successful projects. According to the Smart Market Report, a magazine specialized in construction industry, recently said 'Off-site Prefabrication' is a significant trend related with construction productivity in global construction industry. It is a kind of practice shift from On-site to Off-site. A lot of general contractors in oversea have been using 'Multi-trade MEP Ceiling Rack Prefabrication' method for getting benefits such as decreased cost & schedule and increased labor productivity. Thus, in this paper, critical management factors at each phase from design to installation was derived by researching case studies. Forwardly, it can be a basic guideline for applying Multi-trade MEP Ceiling Rack Prefabrication in Korea construction industry.

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Eco-corridor Master Plan Connecting Urban Forests via the Urban Stream (도시하천(都市河川)을 이용(利用)한 도시림간(都市林間) 생태통로(生態通路) 조성(造成) 기본계획(基本計劃))

  • Kahng, Byung-Seon;Lee, Kyoo-Seock
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.4 no.4
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    • pp.36-45
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    • 2001
  • Natural disturbances and human development can cause habitat fragmentation. Plant and wildlife can become isolated, and habitat fragmentation and shrinkage have been recognized as a key issue facing the conservation of biological diversity. However, eco-corridors can alleviate the problem by providing linkages between isolated patches. The purpose of this study is to plan the eco-corridor for connecting urban forest via the urban stream with low cost and to restore the ecosystem. The results were as follows (1) Falco subbuteo, and Dryocopus martius inhabit in the study site. They are protected species designated by Korean Ministry of Environment. Thus the study site should be preserved as urban wildlife habitat species biodiversity (2) If the biodiversity of the study site is maintained properly, the eco-corridor can be constructed with low cost.

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Structural Arrangement for Functional Requirements of Brain Recombinant 4-Aminobutyrate Aminotransferase

  • Sung, Bo-Kyung;Kim, Young-Tae
    • BMB Reports
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    • v.33 no.1
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    • pp.43-48
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    • 2000
  • 4-Aminobutyrate aminotransferase is a key enzyme of the 4-aminobutyric acid shunt. It converts the neurotransmitter 4-aminobutyric acid to succinic semialdehyde. In order to study the structural and functional aspects of catalytically active Cys residues of pig brain 4-aminobutyrate aminotransferase, we purified the active form in E. coli by coproduction of thioredoxin. The structural arrangement for functional requirements of a dimeric protein using a bifunctional sultbydryl reagent was then characterized, and the spatial proximity between the essential SH groups and a cofactor (pyridoxal-5'-phosphate) binding site was determined. The bifunctional sultbydryl reagent DMDS reacted with the enzyme at the ratio of one molecule per enzyme dimer. This resulted in an approximately 50% loss of enzymatic activity. The spatial proximity of the distance between the essential SH groups and the cofactor-binding site was determined by the energy transfer measurement technique. The result (approximate 20 ${\AA}$) suggested that cross-linking of two sulfhydryl groups with DMDS is not near a PLP binding site.

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