• Title/Summary/Keyword: Vector Potential

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Molecular Cloning and Characterization of a Bile Salt Hydrolase from Lactobacillus acidophilus PF01

  • Oh, Hae-Keun;Lee, Ji-Yoon;Lim, Soo-Jin;Kim, Min-Jeong;Kim, Geun-Bae;Kim, Jung-Hoan;Hong, Soon-Kwang;Kang, Dae-Kyung
    • Journal of Microbiology and Biotechnology
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    • v.18 no.3
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    • pp.449-456
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    • 2008
  • Phenotypic screening for bile salt hydrolase (BSH) activity was performed on Lactobacillus acidophilus PF01 isolated from piglet feces. A gene encoding BSH was identified and cloned from the genomic library of L. acidophilus PF01. The bsh gene and surrounding regions were characterized by nucleotide sequence analysis and were found to contain a single open reading frame (ORF) of 951 nucleotides encoding a 316 amino acid protein. The potential bsh promoter region was located upstream of the start codon. The protein deduced from the complete ORF had high similarity with other BSHs, and four amino acid motifs located around the active site, FGRNXD, AGLNF, VLTNXP, and GXGXGXXGXPGD, were highly conserved. The bsh gene was cloned into the pET21b expression vector and expressed in Escherichia coli BLR(DE3) by induction with 0.1mM of isopropylthiogalactopyranoside. The BSH enzyme was purified with apparent homogeneity using a $Ni^{2+}$-NTA agarose column and characterized. The overexpressed recombinant BSH enzyme of L. acidophilus PF01 exhibited hydrolase activity against tauroconjugated bile salts, but not glycoconjugated bile salts. It showed the highest activity against taurocholic acid. The maximum BSH activity occurred at approximately $40^{\circ}C$. The enzyme maintained approximately 70% of its maximum activity even at $60^{\circ}C$, whereas its activity rapidly decreased at below $37^{\circ}C$. The optimum pH was 6, and BSH activity was rapidly inactivated below pH 5 and above pH 7.

Construction of a full-length cDNA library from Pinus koraiensis and analysis of EST dataset (잣나무(Pinus koraiensis)의 cDNA library 제작 및 EST 분석)

  • Kim, Joon-Ki;Im, Su-Bin;Choi, Sun-Hee;Lee, Jong-Suk;Roh, Mark S.;Lim, Yong-Pyo
    • Korean Journal of Agricultural Science
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    • v.38 no.1
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    • pp.11-16
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    • 2011
  • In this study, we report the generation and analysis of a total of 1,211 expressed sequence tags (ESTs) from Pinus koraiensis. A cDNA library was generated from the young leaf tissue and a total of 1,211 cDNA were partially sequenced. EST and unigene sequence quality were determined by computational filtering, manual review, and BLAST analyses. In all, 857 ESTs were acquired after the removal of the vector sequence and filtering over a minimum length 50 nucleotides. A total of 411 unigene, consisting of 89 contigs and 322 singletons, was identified after assembling. Also, we identified 77 new microsatellite-containing sequences from the unigenes and classified the structure according to their repeat unit. According to homology search with BLASTX against the NCBI database, 63.1% of ESTs were homologous with known function and 22.2% of ESTs were matched with putative or unknown function. The remaining 14.6% of ESTs showed no significant similarity to any protein sequences found in the public database. Gene ontology (GO) classification showed that the most abundant GO terms were transport, nucleotide binding, plastid, in terms biological process, molecular function and cellular component, respectively. The sequence data will be used to characterize potential roles of new genes in Pinus and provided for the useful tools as a genetic resource.

Where is the coronal loop plasma located, within a flux rope or between flux ropes?

  • Lim, Daye;Choe, G.S.;Yi, Sibaek
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.66.3-67
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    • 2015
  • Without scrutinizing reflection, the plasma comprising a coronal loop is usually regarded to reside within a flux rope. This picture seems to have been adopted from laboratory plasma pinches, in which a plasma of high density and pressure is confined in the vicinity of the flux rope axis by magnetic tension and magnetic pressure of the concave inward magnetic field. Such a configuration, in which the plasma pressure gradient and the field line curvature vector are almost parallel, however, is known to be vulnerable to ballooning instabilities (to which belong interchange instabilities as a subset). In coronal loops, however, ideal MHD (magnetohydrodynamic) ballooning instabilities are impeded by a very small field line curvature and the line-tying condition. We, therefore, focus on non-ideal (resistive) effects in this study. The footpoints of coronal loops are constantly under random motions of convective scales, which twist individual loop strands quite randomly. The loop strands with the axial current of the same direction tend to coalesce by magnetic reconnection. In this reconnection process, the plasma in the loop system is redistributed in such a way that a smaller potential energy of the system is attained. We have performed numerical MHD simulations to investigate the plasma redistribution in coalescence of many small flux ropes. Our results clearly show that the redistributed plasma is more accumulated between flux ropes rather than near the magnetic axes of flux ropes. The Joule heating, however, creates a different temperature distribution than the density distribution. Our study may give a hint of which part of magnetic field we are looking to in an observation.

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Development of Bovine Nuclear Transfer Embryos Using Life-span Extended Donor Cells Transfected with Foreign Gene

  • Hwang, Seongsoo;Choi, Eun Joo;You, Seungkwon;Choi, Yun-Jaie;Min, Kwan-Sik;Yoon, Jong-Taek
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.11
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    • pp.1574-1579
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    • 2006
  • This study was performed to determine the developmental potentials of nuclear transfer (NT) embryos using life-span extended cells transfected with a foreign gene as donor cells. A life-span extended bovine embryonic fibroblast cell line was transfected with an expression vector in which the human type II collagen (BOMAR) and ear fibroblasts were used as a donor cell. Cytogenetic analysis was performed to analyze the chromosomal abnormality of donor cells. The fusion rate of 1.8 kV/cm for $15{\mu}sec$ given twice was significantly higher than that of other groups (p<0.05) and the embryos lysed were significantly higher after 1.8 kV/cm for $20{\mu}sec$ given once compared to other groups (p<0.01). The blastocyst development in the ear cell group was statistically significant compared to both BOMAR groups (p<0.01). Both BOMAR groups cultured more than 40 passages (>40 passages) had a lower number of chromosomes; however, fresh granulosa cell (GC) and BOMAR groups cultured less than 20 passages had normal chromosome numbers. Both >40 passages BOMAR groups had numerous obscure debris in metaphase spreads. The transfected foreign gene was expressed in all BOMAR groups, but not in the GC group. Based on these results, the lower developmental potential of NT embryos using life-span extended donor cells transfected with a foreign gene might be a cause of chromosomal abnormality in donor cells.

Analysis of Magnetic Fields Induced by Line Currents using Coupling of FEM and Analytical Solution (선전류에 의해 발생되는 자장의 해석을 위한 유한요소법과 해석해의 결합 기법)

  • Kim, Young-Sun;Cho, Dae-Hoon;Lee, Ki-Sik
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.55 no.3
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    • pp.141-145
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    • 2006
  • The line current problem(2-dimensional space : point source) is not easy to analyze the magnetic field using the standard finite element method(FEM), such as overhead trolley line or transmission line. To supplement such a defect this paper is proposed the coupling scheme of analytical solution and FEM. In analysis of the magnetic field using the standard FEM. If the current region is a relatively small compared to the whole region. Therefore the current region must be finely divided using a large number of elements. And the large number of elements increase the number of unknown variables and the use of computer memories. In this paper, an analytical solution is suggested to supplement this weak points. When source is line current and the part of interest is far from line current, the analytical solution can be coupling with FEM at the boundary. Analytical solution can be described by the multiplication of two functions. One is power function of radius, the other is a trigonometric function of angle in the cylindrical coordinate system. There are integral constants of two types which can be established by fourier series expansion. Also fourier series is represented as the factor to apply the continuity of the magnetic vector potential and magnetic field intensity with tangential component at the boundary. To verify the proposed algorithm, we chose simplified model existing magnetic material in FE region. The results are compared with standard FE solution. And it is good agreed by increasing harmonic order.

Trends in Protein Engineering for Gene Targeting: Homing Endonucleases and Zinc Finger Nucleases (유전자 표적화를 위한 단백질공학 연구동향: Homing Endonucleases and Zinc Finger Nucleases)

  • Cheong, Dea-Eun;Kim, Geun-Joong
    • KSBB Journal
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    • v.25 no.3
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    • pp.215-222
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    • 2010
  • Monogenic diseases are resulted from modifications in a single gene of human cells. Because their treatment with pharmacological medicine have a temporary effect, continuous nursing care and retreatment are required. Gene therapy, gene targeting and induced pluripotent stem cell (iPSC) are considered permanent treatment methods of them. In gene therapy, however, retroviral vectors that have potential toxicity caused by random insertion of harmful virus are used as vehicles for transferring genetic materials. On the other hand, gene targeting could replace and remove the modified gene though homologous recombination (HR) induced by site-specific endonucleases. This short review provides a brief overview on the recently tailored endonucleses with high selectivity for HR.

Extraction and Revision of Building Information from Single High Resolution Image and Digital Map (단일 고해상도 위성영상과 수치지도로부터 건물 정보 추출 및 갱신)

  • Byun, Young-Gi;Kim, Hye-Jin;Choi, Jae-Wan;Han, You-Kyung;Kim, Yong-Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.2
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    • pp.149-156
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    • 2008
  • In this paper, we propose a method aiming at updating the building information of the digital maps using single high resolution satellite image and digital map. Firstly we produced a digital orthoimage through the automatic co-registration of QuickBird image and 1:1,000 digital map. Secondly we extracted building height information through the template matching of digital map's building vector data and the image's edges obtained by Canny operator. Finally we refined the shape of some buildings by using the result from template matching as the seed polygon of the greedy snake algorithm. In order to evaluate the proposed method's effectiveness, we estimated accuracy of the extracted building information using LiDAR DSM and 1:1,000 digital map. The evaluation results showed the proposed method has a good potential for extraction and revision of building information.

Methods for sampling and analysis of marine microalgae in ship ballast tanks: a case study from Tampa Bay, Florida, USA

  • Garrett, Matthew J.;Wolny, Jennifer L.;Williams, B. James;Dirks, Michael D.;Brame, Julie A.;Richardson, R. William
    • ALGAE
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    • v.26 no.2
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    • pp.181-192
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    • 2011
  • Ballasting and deballasting of shipping vessels in foreign ports have been reported worldwide as a vector of introduction of non-native aquatic plants and animals. Recently, attention has turned to ballast water as a factor in the global increase of harmful algal blooms (HABs). Many species of microalgae, including harmful dinoflagellate species, can remain viable for months in dormant benthic stages (cysts) in ballast sediments. Over a period of four years, we surveyed ballast water and sediment of ships docked in two ports of Tampa Bay, Florida, USA. Sampling conditions encountered while sampling ballast water and sediments were vastly different between vessels. Since no single sample collection protocol could be applied, existing methods for sampling ballast were modified and new methods created to reduce time and labor necessary for the collection of high-quality, qualitative samples. Five methods were refined or developed, including one that allowed for a directed intake of water and sediments. From 63 samples, 1,633 dinoflagellate cysts and cyst-like cells were recovered. A native, cyst-forming, harmful dinoflagellate, Alexandrium balechii (Steidinger) F. J. R. Taylor, was collected, isolated, and cultured from the same vessel six months apart, indicating that ships exchanging ballast water in Tampa Bay have the potential to transport HAB species to other ports with similar ecologies, exposing them to non-native, potentially toxic blooms.

Immunization with a Genetically Engineered Uropathogenic Escherichia coli Adhesin-Escherichia coli Enterotoxin Subunit A2B Chimeric Protein

  • Lee, Yong-Hwa;Kim, Byung-O;Pyo, Suhk-Neung
    • Biomolecules & Therapeutics
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    • v.13 no.2
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    • pp.101-106
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    • 2005
  • The generation of secretory IgA antibodies (Abs) for specific immune protection of mucosal surfaces depends on stimulation of the mucosal immune system, but this is not effectively achieved by parenteral or even oral administration of most soluble antigens. Thus, to produce a possible vaccine antigen against urinary tract infections, the uropathogenic E. coli (UPEC) adhesin was genetically coupled to the heat-labile Escherichia coli enterotoxin A2B (ltxa2b) gene and cloned into a pMAL-p2E expression vector. The chimeric construction of pMALfimH/ltxa2b was then transformed into E. coli K-12 TB1 and its nucleotide sequence was verified. The chimeric protein was then purified by applying the affinity chromatography. The purified chimeric protein was confirmed by SDS-PAGE and westem blotting using antibodies to the maltose binding protein (MBP) or the heat labile E. coli subunit B (LTXB), plus the N-terminal amino acid sequence was analyzedd. The orderly-assembled chimeric protein was confirmed by a modified $G_{M1}$-ganglioside ELISA using antibodies to adhesin. The results indicate that the purified chimeric protein was an Adhesin/LTXA2B protein containing UPEC adhesin and the $G_{M1}$-ganglioside binding activity of LTXB. thisstudy also demonstrate that peroral administration of this chimeric immunogen in mice elicited high level of secretory IgA (sIgA) and serum IgG Abs to the UPEC adhesin. The results suggest that the genetically linked LTXA2B acts as a useful mucosal adjuvant, and that adhesin/LTXA2A chimeric protein might be a potential antigen for oral immunization against UPEC.

A Study on the Combined Decision Tree(C4.5) and Neural Network Algorithm for Classification of Mobile Telecommunication Customer (이동통신고객 분류를 위한 의사결정나무(C4.5)와 신경망 결합 알고리즘에 관한 연구)

  • 이극노;이홍철
    • Journal of Intelligence and Information Systems
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    • v.9 no.1
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    • pp.139-155
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    • 2003
  • This paper presents the new methodology of analyzing and classifying patterns of customers in mobile telecommunication market to enhance the performance of predicting the credit information based on the decision tree and neural network. With the application of variance selection process from decision tree, the systemic process of defining input vector's value and the rule generation were developed. In point of customer management, this research analyzes current customers and produces the patterns of them so that the company can maintain good customer relationship and makes special management on the customer who has huh potential of getting out of contract in advance. The real implementation of proposed method shows that the predicted accuracy is higher than existing methods such as decision tree(CART, C4.5), regression, neural network and combined model(CART and NN).

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