• Proceedings of the KAIS Fall Conference
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• 2007.11a
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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.

• Journal of fish pathology
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• v.22 no.3
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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.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.737-750
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• 2015

This study was carried out to construct a DNA profile database for 102 watermelon cultivars through the comparison of polymorphism level and genetic relatedness using genomic microsatellite (gMS) and expressed sequence tag (EST)-microsatellite (eMS) markers. Sixteen gMS and 10 eMS primers showed hyper-variability and were able to represent the genetic variation within 102 watermelon cultivars. With gMS markers, an average of 3.63 alleles per marker were detected with a polymorphism information content (PIC) value of 0.479, whereas with eMS markers, the average number of alleles per marker was 2.50 and the PIC value was 0.425, indicating that eMS detects a lower polymorphism level compared to gMS. Cluster analysis and Jaccard's genetic distance coefficients using the unweighted pair group method with arithmetic average (UPGMA) based on the gMS, eMS, and combined data sets showed that 102 commercial watermelon cultivars could be categorized into 6 to 8 major groups corresponding to phenotypic traits. Moreover, this method was sufficient to identify 78 out of 102 cultivars. Correlation analysis with Mantel tests for those clusters using 3 data sets showed high correlation ($r{\geq}0.80$). Therefore, the microsatellite markers used in this study may serve as a useful tool for germplasm evaluation, genetic purity assessment, and fingerprinting of watermelon cultivars.

• Journal of fish pathology
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• v.23 no.2
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3582-3588
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• 2013

Expressed sequence tag (EST) library was constructed from A. tamarense. Base sequences of EST clones were analyzed and saxitoxin biosynthesis-related genes were cloned. Sequences of 827 clones were analyzed and 564 EST were functionally clustered using Blast searches against GenBank. Main genes in the EST had functions on cellular organization, cell metabolism, energy, cell cycle and DNA processing, cellular transport and transport, cell rescue, defense, death and aging, and transcription. Moreover, expression of S-adenosylmethionine synthetase and H2A histone family genes were increased in the toxic A. tamarense. These results show that two genes could be a good biomarkers for the detection of saxitoxin biosynthesis in the A. tamarense.

• Parasites, Hosts and Diseases
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• v.49 no.3
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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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• v.27 no.4
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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.

• The Korean Journal of Malacology
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• v.30 no.3
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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.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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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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• v.37 no.2
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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.