• International Journal of Industrial Entomology and Biomaterials
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• 제2권1호
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• pp.1-6
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• 2001

This paper reports a few characteristics of seven insect mitochondrial genomes sequenced completely (Bombyx mori, Drosophila melanogaster, D. yakuba, Apis mellifera, Anopheles gambiae, A. quadrimaculatus, and Locusta migratoria). Comparative analysis of complete mt genome sequences from several species revealed a number of interesting features (base composition, gene content, A+T-rich region, and gene arrangement, etc) of insect mitochondrial genome. The properties revealed by our work shed new light on the organization and evolution of the insect mitochondrial genome and more importantly open up the way to clearly aimed experimental studies for understanding critical roles of the regulatory mechanisms (transcription and translation) in mitochondrial gene expression.

• 식물조직배양학회지
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• 제27권4호
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• pp.269-282
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• 2000

Benzylisoquinoline alkaloids are a diverse group of natural products that include many pharmacologically active compounds produced in a limited number of plant families. Despite their complexity, intensive biochemical research has extended our knowledge of the chemistry and enzymology of many important benzylisoquinoline alkaloid pathways, such as those leading to the analgesic drugs morphine and codeine, and the antibiotics sanguinarine and berberine. The use of cultured plant cells as an experimental system has facilitated the identification and characterization of more than 30 benzylisoquinoline alkaloid biosynthetic enzymes, and the molecular cloning of the genes that encode at least 8 of these enzymes. The recent expansion of biochemical and molecular technologies has creat-ed unique opportunities to dissect the mechanisms involved in the regulation of benzylisoquinoline alkaloid biosynthesis in plants. Research has suggested that product accumulation is controlled by the developmental and inducible regulation of several benzylisoquinoline alkaloid biosynthetic genes, and by the subcellular compartmentation of biosynthetic enzymes and the intracellular localization and trafficking of pathway intermediates. In this paper, we review our current understanding of the biochemistry, cell biology, and molecular regulation of benzylisoquinoline alkaloid biosynthesis in plants. We also summarize our own research activities, especially those related to the establishment of protocols for the genetic transformation of benzylisoquinoline alkaloid-producing species, and the development of metabolic engineering strategies in these plants.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.39-39
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• 2003

Methylation of DNA 5-cytosine in mammalian early embryo affects great deal in nuclear reprogramming and chromatin remodeling of developing embryo. Current efforts to clone and produce cloned animals including transgenic animals face various problems including low birth rate, irregular development, and so on. In this report, cDNA for the one of house keeping methyltransfcrase, Dnmt1 was cloned from bovine somatic tissues and was analyzed for its nucleotide sequences to investigate the structure and function of the gene in bovine early development. Nucleotide sequence of bovine Dnmt1 homologue showed 76.8% identity with that of human Dnmtl and 66.4% with mouse Dnmt1. Translated amino acid sequence showed 88.4% homology with human homologue and 75.8% homology with mouse counterpart. Three types of Dnmt1 are reported in mouse and human, and are likely present in bovine tissues. Understanding of role of Dnmt1 in bovine development may shed a light in the field of animal, especially bovine cloning.

• Food Science and Biotechnology
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• 제15권6호
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• pp.889-895
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• 2006

Cytotoxic effects of extracts from Tremella fuciformis strain FB001 were evaluated on the DLD-1 human colon adenocarcinoma cell line and the content of polyphenolic compounds in the extracts were analyzed. Hexane, chloroform, and ethyl acetate subfractions (experimental setting I) exhibited cytotoxic effects on the human colon adenocarcinoma DLD-1 cell line with $IC_{50}$ values of 350, 400, and 450 ppm, respectively. When T. fuciformis was extracted sequentially with ether, ethyl acetate, chloroform, and ethanol (experimental setting II), the ether extract demonstrated potent cytotoxicity with an $IC_{50}$ value of 150 ppm, followed by ethyl acetate and chloroform fractions. If the first extraction solvent was chloroform instead of ether (experimental setting III), exposure of the cell line to chloroform, ethyl acetate, and ether extracts at 1,000 ppm led to cell death. High levels of phenolic compounds were estimated for all hydrophobic extracts, which exhibited cytotoxic effects. We propose that this useful information gives additional support to our understanding of the biology and utility of this particular mushroom.

• Journal of Korean Neurosurgical Society
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• 제62권3호
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• pp.272-287
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• 2019

The mechanistic target of rapamycin (mTOR) pathway coordinates the metabolic activity of eukaryotic cells through environmental signals, including nutrients, energy, growth factors, and oxygen. In the nervous system, the mTOR pathway regulates fundamental biological processes associated with neural development and neurodegeneration. Intriguingly, genes that constitute the mTOR pathway have been found to be germline and somatic mutation from patients with various epileptic disorders. Hyperactivation of the mTOR pathway due to said mutations has garnered increasing attention as culprits of these conditions : somatic mutations, in particular, in epileptic foci have recently been identified as a major genetic cause of intractable focal epilepsy, such as focal cortical dysplasia. Meanwhile, epilepsy models with aberrant activation of the mTOR pathway have helped elucidate the role of the mTOR pathway in epileptogenesis, and evidence from epilepsy models of human mutations recapitulating the features of epileptic patients has indicated that mTOR inhibitors may be of use in treating epilepsy associated with mutations in mTOR pathway genes. Here, we review recent advances in the molecular and genetic understanding of mTOR signaling in epileptic disorders. In particular, we focus on the development of and limitations to therapies targeting the mTOR pathway to treat epileptic seizures. We also discuss future perspectives on mTOR inhibition therapies and special diagnostic methods for intractable epilepsies caused by brain somatic mutations.

• Korean Circulation Journal
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• 제53권6호
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• pp.351-366
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• 2023

Along with the development of immunosuppressive drugs, major advances on xenotransplantation were achieved by understanding the immunobiology of xenograft rejection. Most importantly, three predominant carbohydrate antigens on porcine endothelial cells were key elements provoking hyperacute rejection: α1,3-galactose, SDa blood group antigen, and N-glycolylneuraminic acid. Preformed antibodies binding to the porcine major xenoantigen causes complement activation and endothelial cell activation, leading to xenograft injury and intravascular thrombosis. Recent advances in genetic engineering enabled knock-outs of these major xenoantigens, thus producing xenografts with less hyperacute rejection rates. Another milestone in the history of xenotransplantation was the development of co-stimulation blockaded strategy. Unlike allotransplantation, xenotransplantation requires blockade of CD40-CD40L pathway to prevent T-cell dependent B-cell activation and antibody production. In 2010s, advanced genetic engineering of xenograft by inducing the expression of multiple human transgenes became available. So-called 'multi-gene' xenografts expressing human transgenes such as thrombomodulin and endothelial protein C receptor were introduced, which resulted in the reduction of thrombotic events and improvement of xenograft survival. Still, there are many limitations to clinical translation of cardiac xenotransplantation. Along with technical challenges, zoonotic infection and physiological discordances are major obstacles. Social barriers including healthcare costs also need to be addressed. Although there are several remaining obstacles to overcome, xenotransplantation would surely become the novel option for millions of patients with end-stage heart failure who have limited options to traditional therapeutics.

• Smart Structures and Systems
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• 제33권2호
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• pp.165-175
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• 2024

Rotating beams play a crucial role in representing complex mechanical components that are prevalent in vital sectors like energy and transportation industries. These components are susceptible to the initiation and propagation of cracks, posing a substantial risk to their structural integrity. This study presents a two-stage methodology for detecting the location and estimating the size of an open-edge transverse crack in a rotating Euler-Bernoulli beam with a uniform cross-section. Understanding the dynamic behavior of beams is vital for the effective design and evaluation of their operational performance. In this regard, modal parameters such as natural frequencies and eigenmodes are frequently employed to detect and identify damages in mechanical components. In this instance, the Frobenius method has been employed to determine the first two natural frequencies and corresponding eigenmodes associated with flapwise bending vibration. These calculations have been performed by solving the governing differential equation that describes the motion of the beam. Various parameters have been considered, such as rotational speed, beam slenderness, hub radius, and crack size and location. The effect of the crack has been replaced by a rotational spring whose stiffness represents the increase in local flexibility as a result of the damage presence. In the initial phase of the proposed methodology, a damage index utilizing the slope of the beam's eigenmode has been employed to estimate the location of the crack. After detecting the presence of damage, the size of the crack is determined using a Genetic Algorithm optimization technique. The ultimate goal of the proposed methodology is to enable the development of more suitable and reliable maintenance plans.

• 인터넷정보학회논문지
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• 제21권2호
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• pp.1-8
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• 2020

최근 악성코드를 활용한 APT(Advanced Persistent Threat) 공격의 수가 점차 증가하면서 이를 예방하고 탐지하기 위한 연구가 활발히 진행되고 있다. 이러한 공격들은 공격이 발생하기 전에 탐지하고 차단하는 것도 중요하지만, 발생 공격 사례 또는 공격 유형에 대한 정확한 분석과 공격 분류를 통해 효과적인 대응을 하는 것 또한 중요하며, 이러한 대응은 해당 공격의 공격 그룹을 분석함으로써 정할 수 있다. 따라서 본 논문에서는 공격자 그룹의 특징을 파악하고 분석하기 위한 악성코드를 활용한 유전 알고리즘 기반 공격자 그룹 특징 추출 프레임워크를 제안한다. 해당 프레임워크에서는 수집된 악성코드를 디컴파일러와 디셈블러를 통해 관련 코드를 추출하고 코드 분석을 통해 저자와 관련된 정보들을 분석한다. 악성코드에는 해당 코드만이 가지고 있는 고유한 특징들이 존재하며, 이러한 특징들은 곧 해당 악성코드의 작성자 또는 공격자 그룹을 식별할 수 있는 특징이라고 할 수 있다. 따라서 우리는 저자 클러스터링 방법을 통해 바이너리 및 소스 코드에서 추출한 다양한 특징들 중에 특정 악성코드 작성자 그룹만이 가지고 있는 특징들을 선별하고, 정확한 클러스터링 수행을 위해 유전 알고리즘을 적용하여 주요 특징들을 유추한다. 또한 각 악성코드 저자 그룹들이 가지고 있는 특성들을 기반으로 각 그룹들만을 표현할 수 있는 특징들을 찾고 이를 통해 프로필을 작성하여 작성자 그룹이 정확하게 군집화되었는지 확인한다. 본 논문에서는 실험을 통해 유전 알고리즘을 활용하여 저자가 정확히 식별되는 지와 유전 알고리즘을 활용하여 주요 특징 식별이 가능한지를 확인 할 것이다. 실험 결과, 86%의 저자 분류 정확도를 보이는 것을 확인하였고 유전 알고리즘을 통해 추출된 정보들 중에 저자 분석에 사용될 특징들을 선별하였다.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.423-428
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• 2020

In vitro evolution is a powerful technique for the engineering of yeast strains to study cellular mechanisms associated with evolutionary adaptation; strains with desirable traits for industrial processes can also be generated. There are two distinct approaches to generate evolved strains in vitro: the sequential transfer of cells in the stationary phase into fresh medium or the continuous growth of cells in a chemostat bioreactor via the constant supply of fresh medium. In culture, evolutionary forces drive diverse adaptive mechanisms within the cell to overcome environmental or intracellular stressors. Especially, this engineering strategy has expanded to the field of human cell lines; the understanding of such adaptive mechanisms provides promising targets for the treatment of human genetic diseases and cancer. Therefore, this technology has the potential to generate numerous industrial, medical, and academic applications.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.534-538
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• 2007

Avermectin and its analogs are major commercial antiparasitic agents in the fields of animal health, agriculture, and human infections. To increase our understanding about the genetic mechanism underlying avermectin overproduction, comparative transcriptomes were analyzed between the low producer S. avermitilis ATCC31267 and the high producer S. avermitilis ATCC31780 via a S. avermitilis whole genome chip. The comparative transcriptome analysis revealed that fifty S. avermitilis genes were expressed at least two-fold higher in S. avermitilis ATCC31780. In particular, all the avermectin biosynthetic genes, including polyketide synthase (PKS) genes and an avermectin pathway-specific regulatory gene, were less expressed in the low producer S. avermitilis ATCC31267. The present results imply that avermectin overproduction in S. avermitilis ATCC31780 could be attributed to the previously unidentified fifty genes reported here and increased transcription levels of avermectin PKS genes.