• Journal of Ecology and Environment
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• v.41 no.1
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• pp.9-18
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• 2017

Background: Species in the heterokont genus Synura are colonial and have silica scales whose ultrastructural characteristics are used for classification. We examined the ultrastructure of silica scales and molecular data (nuclear SSU rDNA and LSU rDNA, and plastid rbcL sequences) to better understand the taxonomy and phylogeny within the section Petersenianae of genus Synura. In addition, we report the first finding of newly recorded Synura species from Korea. Results: We identified all species by examination of scale ultrastructure using scanning and transmission electron microscopy (SEM and TEM). Three newly recorded species from Korea, Synura americana, Synura conopea, and Synura truttae were described based on morphological characters, such as cell size, scale shape, scale size, keel shape, number of struts, distance between struts, degree of interconnections between struts, size of base plate pores, keel pores, base plate hole, and posterior rim. The scales of the newly recorded species, which belong to the section Petersenianae, have a well-developed keel and a characteristic number of struts on the base plate. We performed molecular phylogenetic analyses based on sequence data from three genes in 32 strains (including three outgroup species). The results provided strong statistical support that the section Petersenianae was monophyletic, and that all taxa within this section had well-developed keels and a defined number of struts on the base plate. Conclusions: The phylogenetic tree based on sequence data of three genes was congruent with the data on scale ultrastructure. The resulting phylogenetic tree strongly supported the existence of the section Petersenianae. In addition, we propose newly recorded Synura species from Korea based on phylogenetic analyses and morphological characters: S. americana, S. conopea, and S. truttae.

• Mycobiology
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• v.47 no.2
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• pp.200-206
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• 2019

Allelic differences in A and B mating-type loci are a prerequisite for the progression of mating in the genus Pleurotus eryngii; thus, the crossing is hampered by this biological barrier in inbreeding. Molecular markers linked to mating types of P. eryngii KNR2312 were investigated with randomly amplified polymorphic DNA to enhance crossing efficiency. An A4-linked sequence was identified and used to find the adjacent genomic region with the entire motif of the A locus from a contig sequenced by PacBio. The sequence-characterized amplified region marker $7-2_{299}$ distinguished A4 mating-type monokaryons from KNR2312 and other strains. A BLAST search of flanked sequences revealed that the A4 locus had a general feature consisting of the putative HD1 and HD2 genes. Both putative HD transcription factors contain a homeodomain sequence and a nuclear localization sequence; however, valid dimerization motifs were found only in the HD1 protein. The ACAAT motif, which was reported to have relevance to sex determination, was found in the intergenic region. The SCAR marker could be applicable in the classification of mating types in the P. eryngii breeding program, and the A4 locus could be the basis for a multi-allele detection marker.

• Genes and Genomics
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• v.40 no.12
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• pp.1363-1371
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• 2018

One of the main concerns in biology is extracting sophisticated features from DNA sequence for gene interaction determination, receiving a great deal of researchers' attention. The epigenetic modifications along with their patterns have been intensely recognized as dominant features affecting on gene expression. However, studying sequenced-based features highly correlated to this key element has remained limited. The main objective in this research was to propose a new feature highly correlated to epigenetic modifications capable of classification of genes. In this paper, classification of 34 genes in PPAR signaling pathway associated with muscle fat tissue in human was performed. Using different statistical outlier detection methods, we proposed that 5-mers highly correlated to epigenetic modifications can correctly categorize the genes involved in the same biological pathway or process. Thirty-four genes in PPAR signaling pathway were classified via applying a proposed feature, 5-mers strongly associated to 17 different epigenetic modifications. For this, diverse statistical outlier detection methods were applied to specify the group of thoroughly correlated genes. The results indicated that these 5-mers can appropriately identify correlated genes. In addition, our results corresponded to GeneMania interaction information, leading to support the suggested method. The appealing findings imply that not only epigenetic modifications but also their highly correlated 5-mers can be applied for reconstructing gene regulatory networks as supplementary data as well as other applications like physical interaction, genes prioritization, indicating some sort of data fusion in this analysis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.347-363
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• 2019

Malware has its own unique behavior characteristics, like DNA for living things. To respond APT (Advanced Persistent Threat) attacks in advance, it needs to extract behavioral characteristics from malware. To this end, it needs to do classification for each malware based on its behavioral similarity. In this paper, various similarity of Windows malware is estimated; and based on these similarity values, malware's family is predicted. The similarity measures used in this paper are as follows: 'TF-IDF cosine similarity', 'Nilsimsa similarity', 'malware function cosine similarity' and 'Jaccard similarity'. As a result, we find the prediction rate for each similarity measure is widely different. Although, there is no similarity measure which can be applied to malware classification with high accuracy, this result can be helpful to select a similarity measure to classify specific malware family.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.298-300
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• 2004

기존의 생물정보학 연구는 전체 서열들의 매칭을 통한 상동성 연구에 중점을 두고 진행되어 왔다 최근에 서열 데이터베이스의 급격한 증가와 게놈 정보가 축적됨에 따라 서열로부터 다양한 정보를 얻기 위해 서열 데이터 분석에 마이닝 기법을 접목시키고자 하는 다양한 기술들이 제안되고 있다. 단백질과 DNA의 서열 비교는 생물정보학의 기본 작업 기운데 하나이다. 신속하고 자동화 된 서열 비교 능력은 새로운 서열에 대한 기능 판별 및 분석 등 모든 작업을 용이하게 한다 본 논문에서는 동종의 단백질 서열들을 다중 정렬하여 일치하는 구간을 찾아내고, 그 구간에서 아미노산 코드와 위치정보를 이용해 동종 서열들 간의 특정한 패턴 규칙을 찾아내고, 새로운 서열에서 어떤 서열 필턴 특징이 발생하는지를 찾아냄으로써 서얼을 분류하는 방법을 제안한다.

• Journal of Life Science
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• v.21 no.3
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• pp.385-392
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• 2011

The otter (Lutra lutra) in Korea is classified as a first grade endangered species and is managed under state control. We performed a phylogenetic analysis of the otter that inhabits the Changnyeong, Jinju, and Geoje areas in Gyeongsangnamdo, Korea using mtDNA and microsatellite (MS) markers. As a result of the analysis using the 676-bp D-loop sequence of mtDNA, six haplotypes were estimated from five single nucleotide polymorphisms. The genetic distance between the Jinju and Geoje areas was greater than distances within the areas, and the distance between Jinju and Geoje was especially clear. From the phylogenetic tree estimated using the Bayesian Markov chain Monte Carlo analysis by the MrBays program, two subgroups, one containing samples from Jinju and the other containing samples from the Changnyeong and Geoje areas were clearly identified. The result of a parsimonious median-joining network analysis also showed two clear subgroups, supporting the result of the phylogenetic analysis. On the other hand, in the consensus tree estimated using the genetic distances estimated from the genotypes of 13 MS markers, there were clear two subgroups, one containing samples from the Jinju, Geoje and Changnyeong areas and the other containing samples from only the Jinju area. The samples were not identically classified into each subgroup defined by mtDNA and MS markers. It could be inferred that the differential classification of samples by the two different marker systems was because of the different characteristics of the marker systems used, that is, the mtDNA was for detecting maternal lineage and the MS markers were for estimating autosomal genetic distances. Nonetheless, the results from the two marker systems showed that there has been a progressive genetic fixation according to the habitats of the otters. Further analyses using not only newly developed MS markers that will possess more analytical power but also the whole mtDNA are needed. Expansion of the phylogenetic analysis using otter samples collected from the major habitats in Korea should be helpful in scientifically and efficiently maintaining and preserving them.

• Mycobiology
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• v.42 no.2
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• pp.167-173
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• 2014

A ${\beta}$-glucan synthase gene was isolated from the genomic DNA of polypore mushroom Sparassis crispa, which reportedly produces unusually high amount of soluble ${\beta}$-1,3-glucan (${\beta}$-glucan). Sequencing and subsequent open reading frame analysis of the isolated gene revealed that the gene (5,502 bp) consisted of 10 exons separated by nine introns. The predicted mRNA encoded a ${\beta}$-glucan synthase protein, consisting of 1,576 amino acid residues. Comparison of the predicted protein sequence with multiple fungal ${\beta}$-glucan synthases estimated that the isolated gene contained a complete N-terminus but was lacking approximately 70 amino acid residues in the C-terminus. Fungal ${\beta}$-glucan synthases are integral membrane proteins, containing the two catalytic and two transmembrane domains. The lacking C-terminal part of S. crispa ${\beta}$-glucan synthase was estimated to include catalytically insignificant transmembrane ${\alpha}$-helices and loops. Sequence analysis of 101 fungal ${\beta}$-glucan synthases, obtained from public databases, revealed that the ${\beta}$-glucan synthases with various fungal origins were categorized into corresponding fungal groups in the classification system. Interestingly, mushrooms belonging to the class Agaricomycetes were found to contain two distinct types (Type I and II) of ${\beta}$-glucan synthases with the type-specific sequence signatures in the loop regions. S. crispa ${\beta}$-glucan synthase in this study belonged to Type II family, meaning Type I ${\beta}$-glucan synthase is expected to be discovered in S. crispa. The high productivity of soluble ${\beta}$-glucan was not explained but detailed biochemical studies on the catalytic loop domain in the S. crispa ${\beta}$-glucan synthase will provide better explanations.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.283-294
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• 2007

Conventional culture-based methods of enumerating rumen microorganisms (bacteria, archaea, protozoa, and fungi) are being rapidly replaced by nucleic acid-based techniques which can be used to characterise complex microbial communities without incubation. The foundation of these techniques is 16S/18S rDNA sequence analysis which has provided a phylogenetically based classification scheme for enumeration and identification of microbial community members. While these analyses are very informative for determining the composition of the microbial community and monitoring changes in population size, they can only infer function based on these observations. The next step in functional analysis of the ecosystem is to measure how specific and, or, predominant members of the ecosystem are operating and interacting with other groups. It is also apparent that techniques which optimise the analysis of complex microbial communities rather than the detection of single organisms will need to address the issues of high throughput analysis using many primers/probes in a single sample. Nearly all the molecular ecological techniques are dependant upon the efficient extraction of high quality DNA/RNA representing the diversity of ruminal microbial communities. Recent reviews and technical manuals written on the subject of molecular microbial ecology of animals provide a broad perspective of the variety of techniques available and their potential application in the field of animal science which is beyond the scope of this treatise. This paper will focus on nucleic acid based molecular methods which have recently been developed for studying major functional groups (cellulolytic bacteria, protozoa, fungi and methanogens) of microorganisms that are important in nutritional studies, as well as, novel methods for studying microbial diversity and function from a genomics perspective.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.82-93
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• 2004

Phylogenetic relationships among species in Araliaceae were analyzed using PCR-RAPD and sequence of ITS region of nuclear ribosomal DNA based on samples collected in Korea. RAPD analysis showed various polymorphic bands which were able to differentiate species and genus, and specific bands showing variations among individuals within species. Cluster analysis using gel images revealed high molecular variability within species of Aralia eleta. No significant variation was found among cultivated species of Panax ginseng, but they showed high genetic differences with wild type of the species. In ITS analysis, specific sequences for each genus and species were observed and these were allowed to differentiate species and genus. Phylogenetic analysis using ITS sequences showed that Acanthopanax and Kalopanax had a close relationship, and Aralia and Panax are monophyletic, but genus Hedera is different species from other species in family Araliaceae in this study. The results showing close relationship between genera Aralia and Panax were also observed in RAPD analysis. Contrary to the results of RAPD analysis of Panax ginseng, sequence analysis of ITS showed no significant difference between wild mountain ginseng and cultivated species of P. ginseng. Also, both RAPD and ITS analysis of P. ginseng showed no significant genetic variability among cultivation sites. Results indicate that P. ginseng cultivating in Korea is monophyletic. The molecular analysis used in this study agreed on classification using morphological feature. These results suggest that molecular techniques used in this study could be useful for phylogenetic analysis of Araliaceae.

• Journal of Marine Life Science
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• v.6 no.1
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• pp.38-46
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• 2021

The blood clam, Tegillarca granosa, is economically important in marine bivalve and is used in fisheries industry among western Pacific Ocean Coasts especially in Korea, China, and Japan. The number of chromosomes in the blood clam is known as 2n=38, but the genome size and genetic information of the genome are not still clear. In order to predict the genomic size of the T. granosa, the in-silico analysis analysed the genomic size using short DNA sequence information obtained using the NGS Illumina HiSeq platform. As a result, the genomic size of T. granosa was estimated to be 770.61 Mb. Subsequently, a draft genome assembly was performed through the MaSuRCA assembler, and a simple sequence repeat (SSR) analysis was done by using the QDD pipeline. 43,944 SSRs were detected from the genome of T. granosa and 69.51% di-nucleotide, 16.68% trinucleotide, 12.96% tetra-nucleotide, 0.82% penta-nucleotide, and 0.03% hexa-nucleotide were consisted. 100 primer sets that could be used for genetic diversity studies were selected. In the future, this study will help identify the genetic diversity of T. granosa and population genetic studies, and further identify the classification of origin between homogenous groups.