• 제목/요약/키워드: Sequence effect

검색결과 1,327건 처리시간 0.03초

One-Step Selection of Artificial Transcription Factors Using an In Vivo Screening System

  • Bae, Kwang-Hee;Kim, Jin-Soo
    • Molecules and Cells
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    • 제21권3호
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    • pp.376-380
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    • 2006
  • Gene expression is regulated in large part at the level of transcription under the control of sequence-specific transcriptional regulatory proteins. Therefore, the ability to affect gene expression at will using sequencespecific artificial transcription factors would provide researchers with a powerful tool for biotechnology research and drug discovery. Previously, we isolated 56 novel sequence-specific DNA-binding domains from the human genome by in vivo selection. We hypothesized that these domains might be more useful for regulating gene expression in higher eukaryotic cells than those selected in vitro using phage display. However, an unpredictable factor, termed the "context effect", is associated with the construction of novel zinc finger transcription factors--- DNA-binding proteins that bind specifically to 9-base pair target sequences. In this study, we directly selected active artificial zinc finger proteins from a zinc finger protein library. Direct in vivo selection of constituents of a zinc finger protein library may be an efficient method for isolating multi-finger DNA binding proteins while avoiding the context effect.

Cloning, Expression, and Characterization of DNA Polymerase from Hyperthermophilic Bacterium Aquifex pyrophilus

  • Choi, Jeong-Jin;Kwon, Suk-Tae
    • Journal of Microbiology and Biotechnology
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    • 제14권5호
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    • pp.1022-1030
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    • 2004
  • The gene encoding Aquifex pyrophilus (Apy) DNA polymerase was cloned and sequenced. The Apy DNA polymerase gene consists of 1,725 bp coding for a protein with 574 amino acid residues. The deduced amino acid sequence of Apy DNA. polymerase showed a high sequence homology to Escherichia coli DNA polymerase I-like DNA polymerases. It was deduced by amino acid sequence alignment that Apy DNA polymerase, like the Klenow fragment, has only the two domains, the $3'{\rightarrow}5'$ exonuclease domain and the $5'{\rightarrow}3'$ polymerase domain, containing the characteristic motifs. The Apy DNA polymerase gene was expressed under the control of T7lac promoter on the expression vector pET-22b(+) in E. coli. The expressed enzyme was purified by heat treatment, and Cibacron blue 3GA and $UNO^{TM}$ Q column chromatographies. The optimum pH of the purified enzyme was 7.5, and the optimal concentrations of KCl and $Mg^{2+}$ were 20 mM and 3 mM, respectively. Apy DNA polymerase contained a double strand-dependent $3'{\rightarrow}5'$ proofreading exonuclease activity, but lacked any detectable $5'{\rightarrow}3'$ exonuclease activity, which is consistent with its amino acid sequence. The somewhat lower thermostability of Apy DNA polymerase than the growth temperature of A. pyrophilus was analyzed by the comparison of amino acid composition and pressure effect.

Optimal stacking sequence design of laminate composite structures using tabu embedded simulated annealing

  • Rama Mohan Rao, A.;Arvind, N.
    • Structural Engineering and Mechanics
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    • 제25권2호
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    • pp.239-268
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    • 2007
  • This paper deals with optimal stacking sequence design of laminate composite structures. The stacking sequence optimisation of laminate composites is formulated as a combinatorial problem and is solved using Simulated Annealing (SA), an algorithm devised based on inspiration of physical process of annealing of solids. The combinatorial constraints are handled using a correction strategy. The SA algorithm is strengthened by embedding Tabu search in order to prevent recycling of recently visited solutions and the resulting algorithm is referred to as tabu embedded simulated Annealing (TSA) algorithm. Computational performance of the proposed TSA algorithm is enhanced through cache-fetch implementation. Numerical experiments have been conducted by considering rectangular composite panels and composite cylindrical shell with different ply numbers and orientations. Numerical studies indicate that the TSA algorithm is quite effective in providing practical designs for lay-up sequence optimisation of laminate composites. The effect of various neighbourhood search algorithms on the convergence characteristics of TSA algorithm is investigated. The sensitiveness of the proposed optimisation algorithm for various parameter settings in simulated annealing is explored through parametric studies. Later, the TSA algorithm is employed for multi-criteria optimisation of hybrid composite cylinders for simultaneously optimising cost as well as weight with constraint on buckling load. The two objectives are initially considered individually and later collectively to solve as a multi-criteria optimisation problem. Finally, the computational efficiency of the TSA based stacking sequence optimisation algorithm has been compared with the genetic algorithm and found to be superior in performance.

Complete Chloroplast DNA Sequence from a Korean Endemic Genus, Megaleranthis saniculifolia, and Its Evolutionary Implications

  • Kim, Young-Kyu;Park, Chong-wook;Kim, Ki-Joong
    • Molecules and Cells
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    • 제27권3호
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    • pp.365-381
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    • 2009
  • The chloroplast DNA sequences of Megaleranthis saniculifolia, an endemic and monotypic endangered plant species, were completed in this study (GenBank FJ597983). The genome is 159,924 bp in length. It harbors a pair of IR regions consisting of 26,608 bp each. The lengths of the LSC and SSC regions are 88,326 bp and 18,382 bp, respectively. The structural organizations, gene and intron contents, gene orders, AT contents, codon usages, and transcription units of the Megaleranthis chloroplast genome are similar to those of typical land plant cp DNAs. However, the detailed features of Megaleranthis chloroplast genomes are substantially different from that of Ranunculus, which belongs to the same family, the Ranunculaceae. First, the Megaleranthis cp DNA was 4,797 bp longer than that of Ranunculus due to an expanded IR region into the SSC region and duplicated sequence elements in several spacer regions of the Megaleranthis cp genome. Second, the chloroplast genomes of Megaleranthis and Ranunculus evidence 5.6% sequence divergence in the coding regions, 8.9% sequence divergence in the intron regions, and 18.7% sequence divergence in the intergenic spacer regions, respectively. In both the coding and noncoding regions, average nucleotide substitution rates differed markedly, depending on the genome position. Our data strongly implicate the positional effects of the evolutionary modes of chloroplast genes. The genes evidencing higher levels of base substitutions also have higher incidences of indel mutations and low Ka/Ks ratios. A total of 54 simple sequence repeat loci were identified from the Megaleranthis cp genome. The existence of rich cp SSR loci in the Megaleranthis cp genome provides a rare opportunity to study the population genetic structures of this endangered species. Our phylogenetic trees based on the two independent markers, the nuclear ITS and chloroplast MatK sequences, strongly support the inclusion of the Megaleranthis to the Trollius. Therefore, our molecular trees support Ohwi's original treatment of Megaleranthis saniculifolia to Trollius chosenensis Ohwi.

The immediate effect of incorporating short-term slow abdominal respiration into an exercise program on balance and the autonomic nervous system

  • Han, Jaein;Chae, Yoona;Lee, Na-Kyung
    • Physical Therapy Rehabilitation Science
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    • 제8권4호
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    • pp.225-233
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    • 2019
  • Objective: The purpose of this study was to examine the possible effects of incorporating short-term slow-abdominal respiration (SAR) into an exercise program, on balance and the cardiac-related autonomic nervous system (ANS). Design: Cross-over repeated measures design. Methods: Fifteen young and healthy adults were randomly assigned into two groups (7 in the C-R group, 8 in the R-C group), each of which carried out both control sequence (C) and respiration-experiment sequence (R) in the inverse order. In the C sequence, the subjects performed passive exercises and a general exercise program (P-GEP). In the R sequence, the subjects received a short-term SAR training session and then performed the respiration incorporated general exercises program (R-RGEP). Before and after both C and R sequences, the length and the area of the displacement of the center of pressure (COP) and heart rate variability parameters were measured. Results: The total length of the COP displacement in the left single-leg-standing condition showed a significantly greater reduction after R-RGEP in the respiration-experiment sequence than after the P-GEP in the control sequence (p<0.05). The mean heart rate was significantly reduced only after R-RGEP in the respiration-experiment sequence (p<0.05) Conclusions: The slow-abdominal-respiration, trained in a simple manner and integrated into the exercise program in a single session, showed partially positive immediate effects on balance stabilization. The decrease in heart rate indicated possible involvement of the parasympathetic ANS activation in the stability, although it is not enough to decide whether it is purely due to the controlled respiration.

Flutter stability of a long-span suspension bridge during erection

  • Han, Yan;Liu, Shuqian;Cai, C.S.;Li, Chunguang
    • Wind and Structures
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    • 제21권1호
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    • pp.41-61
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    • 2015
  • The flutter stability of long-span suspension bridges during erection can be more problematic and more susceptible to be influenced by many factors than in the final state. As described in this paper, numerical flutter stability analyses were performed for the construction process of Zhongdu Bridge over Yangtze River using the commercial FE package ANSYS. The effect of the initial wind attack angle, the sequence of deck erection, the stiffness reduction of stiffening girders, the structural damping, and the cross cables are discussed in detail. It was found that the non-symmetrical sequence of deck erection was confirmed to be aerodynamically favourable for the deck erection of long-span suspension bridges and the best erection sequence should be investigated in the design phase. While the initial wind attack angle of $-3^{\circ}$ is advantageous for the aerodynamic stability, $+3^{\circ}$ is disadvantageous compared with the initial wind attack angle of $0^{\circ}$ during the deck erection. The stiffness reduction of the stiffening girders has a slight effect on the flutter wind speed of the suspension bridge during erection, but structural damping has a great impact on it, especially for the early erection stages.

Effect of stacking sequence of the bonded composite patch on repair performance

  • Beloufa, Hadja Imane;Ouinas, Djamel;Tarfaoui, Mostapha;Benderdouche, Noureddine
    • Structural Engineering and Mechanics
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    • 제57권2호
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    • pp.295-313
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    • 2016
  • In this study, the three-dimensional finite element method is used to determine the stress intensity factor in Mode I and Mixed mode of a centered crack in an aluminum specimen repaired by a composite patch using contour integral. Various mesh densities were used to achieve convergence of the results. The effect of adhesive joint thickness, patch thickness, patch-specimen interface and layer sequence on the SIF was highlighted. The results obtained show that the patch-specimen contact surface is the best indicator of the deceleration of crack propagation, and hence of SIF reduction. Thus, the reduction in rigidity of the patch especially at adhesive layer-patch interface, allows the lowering of shear and normal stresses in the adhesive joint. The choice of the orientation of the adhesive layer-patch contact is important in the evolution of the shear and peel stresses. The patch will be more beneficial and effective while using the cross-layer on the contact surface.

A novel tetrapeptide for the treatment of hair loss identified in ginseng berry: in silico characterization and molecular docking with TGF-β2

  • Sung-Gyu Lee;Sang Moon Kang;Hyun Kang
    • Journal of Plant Biotechnology
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    • 제49권4호
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    • pp.316-324
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    • 2022
  • Hair loss causes psychological stress due to its effect on appearance. Therefore, the global market for hair loss treatment products is rapidly growing. The present study demonstrated that ginseng berry-derived and sequence-modified peptides promoted the proliferation rate of dermal papilla (DP) cells and keratinocytes, in addition to having antioxidant properties. Moreover, the potential role of these ginseng berry peptides as TGF-β2 antagonists was confirmed through in silico computer docking. In addition to promoting the growth of ,the ginseng berry-derived peptides also promoted the proliferation of keratinocytes experimental Particularly, an unmodified ginseng berry-derived peptide (GB-1) and two peptides with sequence modifications (GB-2 and GB-3) decreased ROS generation and exhibited a protective effect on damaged HaCaT keratinocytes. Computer-aided peptide discovery was conducted to identify the potential interactions of important proteins with transforming growth factor-beta 2 (TGF-β2), a key protein that plays a crucial role in the human hair growth cycle. Our results demonstrated that MAGH, an amino acid sequence present in herbal supplements and plant-based natural compounds, can inhibit TGF-β2.