• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2007년도 추계학술발표논문집
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• pp.233-236
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• 2007

현재 생물정보학에서는 무수히 많은 생물들에서 엄청난 양의 EST(expressed sequence tag) 정보가 나온다. 본 논문에서는 그런 정보들을 가지고 대사경로를 유추할 수 있는 전문가 시스템을 개발하고자 한다. 현재까지의 대사경로 탐색은 발견해 놓은 데이터를 가지고 전부 수작업으로 이루어진다. 그러한 과정을 자동화 시키고자 하는 연구가 많이 진행되고 있다. 본 논문에서는 전문가 시스템을 활용하여 생물정보학의 EST(expressed sequence tag) 데이터에서 효율적으로 대사경로를 찾을 수 있도록 하는 방안을 제시한다.

• 한국어병학회지
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• 제22권3호
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• pp.343-352
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• 2009

Natural-killer-cell-enhancing factor (NKEF) belongs to the newly defined peroxiredoxin (Prx) family. It was originally isolated from human erythroid cells. The black rockfish NKEF cDNA was identified through the expressed sequence tag (EST) analysis of PBLs libraries. The full-length NKEF cDNA was 1433 bp long and contained an open reading frame (ORF) of 594 bp that encoded 198 amino-acid residues. The 5' UTR had a length of 39 bp, and the 3’UTR 800 bp. The deduced amino-acid sequence of the black rockfish had a density 93.4, 92.9, 87.8, 85.8, 84.8, 83.8, 80.3, 79.7, 77.2, and 75.2% that of the pufferfish, olive flounder, channel catfish, zebrafish, chicken, common carp, Myotis lucifugus, cattle, human PrxI, rat PrxI, human NKEF-A, and Xenopus tropicalis, respectively. The NKEF gene was expressed in all the tissues of the black rockfish. The RT-PCR indicated that the NKEF transcripts were predominantly in the spleen and gill, less dominantly in the PBLs, head kidney, trunk kidney, and liver, and least in the intestine and muscles. This is the first report on the existence of the NKEF-A gene in black rockfish.

• 원예과학기술지
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• 제33권5호
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• pp.737-750
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• 2015

국내에서 시판되고 있는 수박 102 품종에 대한 DNA 프로 파일 데이터베이스를 구축하기 위하여 genomic microsatellite(gMS)와 expressed sequence tag(EST) microsatellite(eMS) 마커의 다형성 정도의 비교와 유전적 연관성 분석을 통한 품종식별력 검정 등에 대한 일련의 연구를 수행하였다. 수박 gMS 마커를 이용하여 국내에서 시판되고 있는 수박 102 품종을 검정하였을 때 마커당 3.63개의 평균 대립유전자가 검출되었으며, 평균 PIC 값은 0.479로 나타났다. 이에 반해 eMS 마커는 평균 대립유전자의 수가 2.50개, PIC 값이 0.425로 나타나 gMS 마커보다 다형성 정도가 낮게 나타났다. gMS와 eMS 및 이들 두 종류의 마커를 병합하여 작성된 계통도는 microsatellite 마커의 다형성에 따라 수박 102개 품종을 6-8개의 그룹으로 구분하였고 대부분의 품종의 식별이 가능하였다. 3가지 마커 유형에 따라 작성된 계통도를 Mantel test에 의해 상관 정도를 분석하였을 때 높은 상관($r{\geq}0.80$)을 나타내었다. 따라서 본 연구에 활용된 microsatellite 마커는 수박 유전자원의 특성평가, 순도검정 및 품종의 지문화 작업의 수단으로 유용하게 활용될 수 있을 것이다.

• 한국어병학회지
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• 제23권2호
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• pp.229-238
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• 2010

We constructed a rock bream (Oplegnathus fasciatus) liver cDNA library and a total of 1533 expressed sequence tag (EST) clones were generated. Gene annotation procedures and homology searches of the sequenced ESTs were analyzed using BLASTX. Of the 1533 EST clones, 1165 different ESTs showed significant homology to previously described genes while 368 ESTs were unidentified, hypothetical, or unnamed proteins. Encoding 106 different sequences were identified as putative bio-defense genes or genes associated with immune response.

• 한국산학기술학회논문지
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• 제14권7호
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• pp.3582-3588
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• 2013

A. tamarense로부터 ESTs library를 제작하였다. 이들의 염기서열을 분석하여 STX 생합성 관련 유전자를 클로닝하였다. 연구결과 827 클론의 염기서열이 분석되었고, 564개의 EST가 GenBank에서의 Blast search를 사용하여 기능에 따라 분류되었다. EST에서의 주요 유전자는 cellular organization, cell metabolism, energy, cell cycle과 DNA processing, cellular transport와 transport, cell rescue, defense, death와 aging 및 transcription 등으로 분석되었다. 특히 S-adenosylmethionine synthetase와 H2A histone family 유전자의 발현이 독성 A. tamarense에서 증가하였다. 이러한 결과는 두 개의 유전자가 A. tamarense에서의 삭시톡신 생합성을 검출하기 위한 좋은 바이오마커가 될 수 있음을 보여준다.

• Parasites, Hosts and Diseases
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• 제49권3호
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• pp.221-228
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• 2011

Rodent malaria parasites, such as Plasmodium berghei, are practical and useful model organisms for human malaria research because of their analogies to the human malaria in terms of structure, physiology, and life cycle. Exploiting the available genetic sequence information, we constructed a cDNA library from the erythrocytic stages of P. berghei and analyzed the expressed sequence tag (EST). A total of 10,040 ESTs were generated and assembled into 2,462 clusters. These EST clusters were compared against public protein databases and 48 putative new transcripts, most of which were hypothetical proteins with unknown function, were identified. Genes encoding ribosomal or membrane proteins and purine nucleotide phosphorylases were highly abundant clusters in P. berghei. Protein domain analyses and the Gene Ontology functional categorization revealed translation/protein folding, metabolism, protein degradation, and multiple family of variant antigens to be mainly prevalent. The presently-collected ESTs and its bioinformatic analysis will be useful resources to identify for drug target and vaccine candidates and validate gene predictions of P. berghei.

• Archives of Pharmacal Research
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• 제27권4호
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• pp.422-428
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• 2004

Expressed sequence tags (ESTs) were generated from two 3'-directed CDNA libraries constructed from quiescent and activated rat hepatic stellate cell (HSC) to analyze the expression profiles of active genes in both cells. From quiescent and activated HSC, 694 ESTs and 779 ESTs, respectively, were obtained after excluding those having shorter than 30 bp. Amonq ESTs obtained from quiescent and activated HSC, 68 and 73 kinds of ESTs (186 clones and 236 clones), respectively, appeared more than once, implying that their genes are expressed highly in each cell type. 52 among 73 ESTs appeared only in the activated HSC 47 amonq 68 ESTs only in the normal HSC, and 21 in both cells. The genes of these 52 ESTs were assumed to be expressed more highly in the activated HSC. To confirm the high expression of genes of which the ESTs appeared more than twice in the activated HSC, northern hybridization was carried out with RNAs derived from rat normal and fibrotic liver using each of 18 EST DNAs as probe. 13 ESTs showed more intense bands with RNA isolated from the fibrotic liver than normal liver. From these results, we confirm the positive correlation between abundance of transcript in activated HSCs and the expression level in fibrotic liver, The expression profile of the transcripts serves as an important tool in understanding the biological properties of HSC.

• 한국패류학회지
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• 제30권3호
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• pp.197-210
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• 2014

Single nucleotide polymorphisms (SNPs) are widely acknowledged as the marker of choice for many genetic and genomic applications because they show co-dominant inheritance, are highly abundant across genomes and are suitable for high-throughput genotyping. Here we evaluated the applicability of SNP markers developed from Crassostrea gigas and C. virginica expressed sequence tags (ESTs) in closely related Crassostrea and Ostrea species. A total of 213 putative interspecific level SNPs were identified from re-sequencing data in six amplicons, yielding on average of one interspecific level SNP per seven bp. High polymorphism levels were observed and the high success rate of transferability show that genic EST-derived SNP markers provide an efficient method for rapid marker development and SNP discovery in closely related oyster species. The six EST-SNP markers identified here will provide useful molecular tools for addressing questions in molecular ecology and evolution studies including for stock analysis (pedigree monitoring) in related oyster taxa.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2001년도 추계학술발표논문집 (상)
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• pp.105-108
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• 2001

cDNA(complementary DNA)를 복제(cloneing)하여 염기 서열화 한 EST(Expressed Sequence Tag) 데이터는 여러 생물체들의 염기서열 정보들과 비교를 통해 유사점을 찾거나 기능적 부위 검색을 통해 유전자 기능을 추정한 수 있어 기능 유전체 연구에 많이 사용되고 있다. EST 데이터를 식물은 특정종(Species)별로, 동물의 경우 종의 조직별로 클러스터링 함으로써 아직 알려지지 않은 종의 유전자를 밝혀낼 수 있음은 물론 유전자의 발현에 따른 단백질의 기능도 알아낼 수 있다. 따라서 이 논문에서는 NCBI에서 flatfile 형태로 제공하는 EST 데이터를 분석하여 관계형 데이터베이스로 모델링하고 구축하였다. 또한 EST 데이터의 효율적인 사용을 위하여 데이터를 특정 종의 조직별로 클러스터링하여 제공하는 시스템을 설계하고 구현하였다.

• Journal of Ginseng Research
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• 제37권2호
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• pp.227-247
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• 2013

MicroRNAs (miRNAs) are a class of recently discovered non-coding small RNA molecules, on average approximately 21 nucleotides in length, which underlie numerous important biological roles in gene regulation in various organisms. The miRNA database (release 18) has 18,226 miRNAs, which have been deposited from different species. Although miRNAs have been identified and validated in many plant species, no studies have been reported on discovering miRNAs in Panax ginseng Meyer, which is a traditionally known medicinal plant in oriental medicine, also known as Korean ginseng. It has triterpene ginseng saponins called ginsenosides, which are responsible for its various pharmacological activities. Predicting conserved miRNAs by homology-based analysis with available expressed sequence tag (EST) sequences can be powerful, if the species lacks whole genome sequence information. In this study by using the EST based computational approach, 69 conserved miRNAs belonging to 44 miRNA families were identified in Korean ginseng. The digital gene expression patterns of predicted conserved miRNAs were analyzed by deep sequencing using small RNA sequences of flower buds, leaves, and lateral roots. We have found that many of the identified miRNAs showed tissue specific expressions. Using the insilico method, 346 potential targets were identified for the predicted 69 conserved miRNAs by searching the ginseng EST database, and the predicted targets were mainly involved in secondary metabolic processes, responses to biotic and abiotic stress, and transcription regulator activities, as well as a variety of other metabolic processes.