• 한국수학교육학회지시리즈B:순수및응용수학
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• 제26권3호
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• pp.177-188
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• 2019

Suppose G is a molecular graph with edge set E(G). The hyper-Zagreb index of G is defined as $HM(G)={\sum}_{uv{\in}E(G)}[deg_G(u)+deg_G(v)]^2$, where $deg_G(u)$ is the degree of a vertex u in G. In this paper, all chemical trees of order $n{\geq}12$ with the first twenty smallest hyper-Zagreb index are characterized.

• 천문학회보
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• 제44권1호
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• pp.33.1-33.1
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• 2019

Protostars grow their mass by the accretion of disk material, which is infalling from the envelope. This accretion process is important to the physical and chemical conditions of the disk and envelope, and thus, the planets yet to be formed from the disk material. Therefore, if we map the physical and chemical properties of disks and envelopes, we can study indirectly the accretion process in star formation. In particular, the chemical distribution in the disk and the inner envelope of a young stellar object is greatly affected by the thermal history, which is mainly determined by the accretion process in the system. In my talk, I will review the episodic accretion model for the low mass star formation and observational efforts to find the evidence of episodic accretion. Finally, I will present our recent ALMA detection of several complex organic molecules associated directly with the planet formation in V883 Ori, which is in the burst accretion phase.

• 미생물학회지
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• 제41권2호
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• pp.140-145
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• 2005

상업적으로 중요한 macrolide계 항진균 학생물질인 natamycin을 생산하는 Streptomyces natalensis ATCC27448의 환자 유전학적인 연구를 위해 대장균으로부터 S. natalensis로 plasmid DNA를 직접 도입하는 형질전환법을 확립하였다. 이러한 S. natalensis의 형질전환은 oriT와 attP 단편을 가지고 있는, ${\Phi}C31$ 유래의 integration 벡터인 pSET152를 이용하여 Escherichia coli ET12567/pUZ28002을 DNA 공여체(donor)로 이용한 접합전달법(conjugal transfer)을 사용하여 확립하였다. 접합전달의 가장 높은 효율은 10 mM의 $MgCl_2$를 포함한 MS 배지에서, $6.25\times10^8$의 E. coli 공여체와 열처리를 하지 않은 S. natalensis의 포자를 사용하여 얻어졌다. 또 얻어진 접합전달체 (exconjugant)에 대하여 southern blot hybridization과 벡터가 삽입된 염색체부분의 염기서열분석을 통해 attB site와 pseudo-attB site를 확인하다. attB site의 경우에는 다른 방선균들처럼 S. natalensis 염색체의 pirin 상동체를 코드하는 ORF내에 존재하였으나 pseudo-attB site는 염색체내 다른 site (GenBank accession no. $YP\_117731$)에 존재하였고 그 염기서열은 attB 염기서열과 차이를 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.678-682
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• 2010

The deletion of sti from the Streptomyces plasmid pIJ101 made its derivative pHZ1358 an efficient vector for gene disruption and replacement. Here, pHZ1358 was further optimized by the construction of a derivative plasmid pJTU1278, in which a cassette carrying multiple cloning sites and a lacZ selection marker were introduced for convenient plasmid construction in E. coli. In addition, the oriT region of pJTU1278 was also deleted, generating a vector (pJTU1289) that can be used specifically for PCR-targeting. The efficient usage of these vectors was demonstrated by the deletion of the gene involved in avermectin biosynthesis in S. avermitilis.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1986년도 추계학술대회
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• pp.516.2-516
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• 1986

DNA subfragments, sopA, sopB, and sopC supporting stable maintenance of an oriC plasmid, were derived from mini-F plasmid DNA (EcoRI restriction fragment, f5) after digestion with restriction endonucleases, and cloned in vector plasmid pBR322. The recombinant plasmid obtained were introduced into E. coli KY7231 and E. coli CSR603, and proteins specified by the mini-F fragments were analysed by SDS-polyacrylamide gel electrophoresis. Two proteins encoded by the F fragments were detected, having molecular weights of 41,000 and 37.000. The sopA protein (41K) encoded by a plasmid pXX288 was observed in the cytoplasm, whereas the sopB protein (37K) encoded by a plasmid pXX157 was in the membrane fraction. There was no novel protein band detected in the cell with a plasmid pXX300, which contained sopC fragment. Gene products of a plasmid pXX167, which is comprised of sopA, sopB, and sopC, were not detectable. Fluorography after one and two dimensional gel electrophoresis of the lysates showed that these two proteins were overproduced in the cells which were allowed to incorporate radioactive amino acid after plasmid amplification by chloramphenicol treatment. The isoelectric points of the sopA and sepB proteins were 6.6 and 7.0, respectively.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.535-538
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• 2000

Streptomyces lavendulae FRI-5 produces the ${\gamma}$-butyrolactone autoregulator IM-2, which is required for nucleoside antibiotic producetion. We have developed a system for introducing DNA into S. lavendule FRI-5 via conjugal transfer from Esherichia cole. Conditions were established for conjugation of the oriT-and attP-containing plasmid pSET152 from E. coli ET12567 (pUZ8002) to FRI-5. Conjugation resulted in integration of the plasmid at the chromosomal C31 attB site. The frequency of intergeneric conjugation varied with the medium used. The highest frequency ($1.6\times10-5$ per recipient) was obtained on ISP medium 2 containing 10mM MgCl2. Southern blot and phenotypic analyses of exconjugants revealed that S. lavendulae FRI-5 contains a unique C31 attB site, and that integration of heterologous DNA into the attB site did not interfere with morphological differentiation or IM-2-dependent signal transduction, including the production of a blue pigment. This system will now enable detailed genetic analysis of the regulation of antibiotic production in S. lavendulae FRI-5.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.872-880
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• 2003

Three vectors, pSG1, 2, and 3, which facilitate in vivo expression technology (IVET) in Gram-negative bacteria, were developed. Vectors pSG1and 2 are derivatives of ColE1, and pSG3 is a derivative of an R6K replicon. These vectors contain oriT sites that allow mobilization when the RK2 Tra functions are provided in trans. These vectors contain promoterless lacZ (pl-lacZ) and promoterless aph (pl-aph) transcriptionally fused together, which allow qualitative and quantitative measurements of the expression of genes in the genome of bacterial cells. pSG1 and 3 contain gentamicin-resistance genes, and pSG2 carries a streptomycin-/spectinomycin-resistance gene, allowing for selection of recombinants generated by a single crossover between a library fragment cloned into a pSG vector and the identical region in the genome of a bacterial species from which the library fragment originated. These vectors were successfully applied to the generation of random fusions at high rates in the genomes of four representative Gram-negative bacteria. In addition, the expression level of ${\beta}-galactosidase$ and the degree of resistance to kanamycin in cells with fusions generated by these vectors were found to be linearly correlated, proving that these vectors can be used for IVET.

• Journal of Microbiology and Biotechnology
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• 제13권3호
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• pp.457-462
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• 2003

The complete nucleotide sequence of a plasmid, pMG1, isolated from Bifidobacterium longum MG1 has been determined. This plasmid, composed of 3,862 base pairs with 65.1% of G+C content. harbors two major open reading frames (ORF) encoding putative proteins of 29 kDa (ORF I) and 71 kDa (ORF II). ORF I showed relatively high amino acid sequence homology with replication proteins of other plasmids from Gr Im-positive and -negative bacteria. Upstream of ORF I, four sets of tandem repeat sequences resembling the iteron structure of related plasmids were found. S1 endonuclease treatment and Southern blot analysis revealed that pMG1 accumulates single-stranded DNA (ssDNA) intermediate, which indicate i the rolling circle replication (RCR) mechanism of this plasmid. Homology search indicated that ORF II encodes plasmid mobilization protein, and the presence of highly conserved oriT sequence in the upstream of this gene supported this assumption. RT-PCR showed that only ORF I is expressed in vivo. Based on these results, pMG 1 was exploited to construct a shuttle vector, pBES2. It was successfully transformed into Bifidobacterium and maintained stably.

• 정보처리학회논문지D
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• 제11D권7호
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• pp.1459-1466
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• 2004

소프트웨어 응용 분야의 확대로 인해, 소프트웨어는 더 크고, 더 복잡해지고 있다. 게다가 개발 기간의 단축 및 비용의 절감${\cdot}$품질의 향상 또한 요구되고 있다. 이러한 요구를 충족시키기 위해 여러 효율적인 방법이 제안되었고, 구현되었다. 대표적으로 프로세스 개선과 객체지향 개발, 요구공학, 소프트웨어 메트릭스 등이 있다. 이러한 수많은 방법 중에서 요구공학은 고품질의 소프트웨어 개발의 기반이 된다. 즉, 고품질의 소프트웨어를 개발하기 위해서는 먼저 요구를 획득하고, 기술하여야 하며, 이에 대한 검증과 관리를 통해 요구사양서의 품질을 향상시켜 가야 한다. 본 논문에서는 IEEE Std-830-1998의 좋은 요구사양서가 가져야 할 특성을 중심으로, 요구사양서에 기술된 내용 자체를 정량적으로 품질 평가할 수 있는 메트릭스를 제안하였다.

• 한국응용곤충학회지
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• 제34권4호
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• pp.344-349
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• 1995

해충의 방제에 효과적으로 이요할 수 있는 Bactllus thuringiensis 균주를 분리하기 위하여 전국의 다양한 토양을 채취하여 B. thuringiensis의 분포와 독성을 조사하였다. 총 548개의 토양을 전국 각지에 채취하여 포자와 내독소 단백질을 생산하는 64개의 B. thuringiensis를 분리했다. 분리된 64개의 B. thuringiensis를 나비목의 누에(Bombyx mori), 파리목의 빨간집모기(Culex pipens), 딱정벌레목의 쌀바구미(Sitophilus oryzae)의 세 종에 대해서 독성을 검정한 결과, 누에에 독성을 띠는 균주가 42.2%로 가장 많았으며, 누에와 빨간집모기에 동시에 독성을 띠는 균주가 31.3%, 빨간집모기에 독성을 띠는 균주는 20.3%의 비율로 분리되어 다양한 독성 분포를 보였다. 그러나 쌀바구미에 독성을 띠는 균주는 분리되지 않았고, 내독소 단백질은 형성하지만 독성이 없는 무독성 B. thuringiensis가 62%의 비율로 분리되었다.