• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.1045-1051
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• 2021

Eighty-nine different types of commercially salt-fermented fishery products comprising various raw materials were analyzed for total aerobic bacteria, number of coliform bacteria, fecal coliform, and Escherichia coli. The food-poisoning bacterial content of the samples was investigated using next-generation sequencing. The mean mass of total aerobic bacteria in Jeotgal was 6-1.8×10⁹ CFU/g, and that in Aekjeot and Sikhae was 4-2.2×10⁵ CFU/mL and 1.9×10⁵-8.4×10⁸ CFU/g, respectively. Coliform bacteria were detected in 9 (28.1%) of 32 Jeotgal samples; 15 (46.8%) of 32 seasonal Jeotgal samples; and in 5 (55.5%) of 9 Sikhae samples. Fecal coliform and E. coli were not detected in 86 of the 89 samples. Yersinia enterocolitica was detected only in Galchi jeot (salt-fermented hairtail) (1 type) and not in other Jeotgal samples. These results contribute to our knowledge regarding the bacterial stability of salt-fermented fishery products.

• Korean Journal of Plant Taxonomy
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• v.48 no.4
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• pp.260-277
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• 2018

The evolution of chromosome numbers and the karyotype structure is a prominent feature of plant genomes contributing to or at least accompanying plant diversification and eventually leading to speciation. Polyploidy, the multiplication of whole chromosome sets, is widespread and ploidy-level variation is frequent at all taxonomic levels, including species and populations, in angiosperms. Analyses of chromosome numbers and ploidy levels of 252 taxa of Korean non-commelinid monocots indicated that diploids (ca. 44%) and tetraploids (ca. 14%) prevail, with fewer triploids (ca. 6%), pentaploids (ca. 2%), and hexaploids (ca. 4%) being found. The range of genome sizes of the analyzed taxa (0.3-44.5 pg/1C) falls well within that reported in the Plant DNA C-values database (0.061-152.33 pg/1C). Analyses of karyotype features in angiosperm often involve, in addition to chromosome numbers and genome sizes, mapping of selected repetitive DNAs in chromosomes. All of these data when interpreted in a phylogenetic context allow for the addressing of evolutionary questions concerning the large-scale evolution of the genomes as well as the evolution of individual repeat types, especially ribosomal DNAs (5S and 35S rDNAs), and other tandem and dispersed repeats that can be identified in any plant genome at a relatively low cost using next-generation sequencing technologies. The present work investigates chromosome numbers (n or 2n), base chromosome numbers (x), ploidy levels, rDNA loci numbers, and genome size data to gain insight into the incidence, evolution and significance of polyploidy in Korean monocots.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.71-71
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• 2019

The genus Cenchrus (Poaceae), containing ca. 23 species, is distributed throughout Australia, Africa, Indian sub-continent, and America. In Korea, Cenchrus longispinus (Hack.) Fernald, especially introduced to Daecheong Island in 1999, is one of the most hazardous invasive plant which causes serious environmental threats, biodiversity damages and physically negative impact on humans and animals. Based on the next-generation sequencing (NGS) technology, we characterized the chloroplast (cp) genome sequences of C. longispinus which contains a large single copy (LSC; 80,223 bp), a small single copy (SSC; 12,449 bp), separated by a pair of inverted repeats (IRs; 22,236 bp). Additionally, we analyzed the cp genome sequences of Cenchrus echinatus L. which contains a large single copy (LSC; 80,220 bp), a small single copy (SSC; 12,439 bp), separated by a pair of inverted repeats (IRs; 22,236 bp). These cp genomes consist of 75 unique genes, 4 rRNA coding genes, 33 tRNA coding genes and 21 duplicated in the IR regions, of which the gene content and organization are similar to the other Poaceae cp genomes. We selected 40 potential regions in cp genomes of two Cenchrus species and one Korean Pennisetum species to develop new single nucleotide polymorphism (SNP) markers for identifying C. longispinus based on amplification-refractory mutation system (ARMS) technique. The markers, inferred from SNP in matK and ndhF genes, show effectiveness to recognize C. longispinus from C. echinatus and Korean native species Pennisetum alopecuroides (L.) Spreng.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.324-332
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• 2018

BACKGROUND: Insects are ectothermic organisms in terrestrial ecosystems and play various roles such as controlling plant biomass and maintaining species diversity. Because insects are ectothermic, their physiological responses are very sensitive to environmental temperature which determines survival and distribution of insect population and that affects climate change. This study aimed to identification of genes contributing to fitness under high temperature. METHODS AND RESULTS: To identify genes contributing to fitness under high temperature, the transcriptomes of fat body in Plutella xyostella larva have been analyzed via next generation sequencing. From the fat body transcriptomes, structure-related proteins, heat shock proteins, antioxidant enzymes and detoxification proteins were identified. Genes encoding proteins such as structural proteins (cuticular proteins, chitin synthase and actin), stress-related protein (cytochrome P450), heat shock protein and antioxidant enzyme (catalase) were up-regulated at high temperature. In contrast expression of glutathione S transferase was down-regulated. CONCLUSION: Identifications of temperature-specific up- or down-regulated genes can be useful for detecting temperature adaptation and understanding physiological responses in insect pests.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.290-296
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• 2019

Objective: Pigs share many physiological, anatomical and genomic similarities with humans, which make them suitable models for biomedical researches. Understanding the genetic status of Yucatan miniature pigs (YMPs) and their association with human diseases will help to assess their potential as biomedical model animals. This study was performed to identify non-synonymous single nucleotide polymorphisms (nsSNPs) in selective sweep regions of the genome of YMPs and present the genetic nsSNP distributions that are potentially associated with disease occurrence in humans. Methods: nsSNPs in whole genome resequencing data from 12 YMPs were identified and annotated to predict their possible effects on protein function. Sorting intolerant from tolerant (SIFT) and polymorphism phenotyping v2 analyses were used, and gene ontology (GO) network and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses were performed. Results: The results showed that 8,462 genes, encompassing 72,067 nsSNPs were identified, and 118 nsSNPs in 46 genes were predicted as deleterious. GO network analysis classified 13 genes into 5 GO terms (p<0.05) that were associated with kidney development and metabolic processes. Seven genes encompassing nsSNPs were classified into the term associated with Alzheimer's disease by referencing the genetic association database. The KEGG pathway analysis identified only one significantly enriched pathway (p<0.05), hsa04080: Neuroactive ligand-receptor interaction, among the transcripts. Conclusion: The number of deleterious nsSNPs in YMPs was identified and then these variants-containing genes in YMPs data were adopted as the putative human diseases-related genes. The results revealed that many genes encompassing nsSNPs in YMPs were related to the various human genes which are potentially associated with kidney development and metabolic processes as well as human disease occurrence.

• Korean Journal of Veterinary Research
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• v.58 no.4
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• pp.177-182
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• 2018

Canine adenovirus type 2 (CAV-2) infection results in significant respiratory illness in dogs. Isolating and culturing CAV-2 allows for investigations into its pathogenesis and the development of vaccines and diagnostic assays. In this study, we successfully isolated a virus from a naturally infected dog in Gyeonggi-do, Korea. The virus was propagated in Madin-Darby canine kidney (MDCK) and Vero cells and showed a specific cytopathic morphology that appeared similar to a bunch of grapes. The virus was first confirmed as CAV-2 based on these cytopathic effects, an immunofluorescence assay, hemagglutination assay, and electron microscopy. The viral titer of the isolate designated APQA1601 reached $10^{6.5}$ 50% tissue culture infections dose per mL in MDCK cells and exhibited no hemagglutination units with erythrocytes from guinea pig. The virus was also confirmed by polymerase chain reaction and next-generation sequencing. The APQA1601 strain had the highest similarity (~99.9%) with the Toronto A26/61 strain, which was isolated in Canada in 1976 when the nucleotide sequences of the full genome of the APQA1601 strain were compared with those of other CAV strains. Isolating CAV-2 will help elucidate the biological properties of CAV-2 circulating in Korean dogs.

• Molecules and Cells
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• v.42 no.1
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• pp.87-95
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• 2019

Long interspersed element-1 (LINE-1 or L1) is an autonomous retrotransposon, which is capable of inserting into a new region of genome. Previous studies have reported that these elements lead to genomic variations and altered functions by affecting gene expression and genetic networks. Mounting evidence strongly indicates that genetic diseases or various cancers can occur as a result of retrotransposition events that involve L1s. Therefore, the development of methodologies to study the structural variations and interpersonal insertion polymorphisms by L1 element-associated changes in an individual genome is invaluable. In this study, we applied a systematic approach to identify human-specific L1s (i.e., L1Hs) through the bioinformatics analysis of high-throughput next-generation sequencing data. We identified 525 candidates that could be inferred to carry non-reference L1Hs in a Korean individual genome (KPGP9). Among them, we randomly selected 40 candidates and validated that approximately 92.5% of non-reference L1Hs were inserted into a KPGP9 genome. In addition, unlike conventional methods, our relatively simple and expedited approach was highly reproducible in confirming the L1 insertions. Taken together, our findings strongly support that the identification of non-reference L1Hs by our novel target enrichment method demonstrates its future application to genomic variation studies on the risk of cancer and genetic disorders.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.10
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• pp.231-238
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• 2019

Analyzing next-generation genome sequencing data in a conventional way using single server may take several tens of hours depending on the data size. However, in order to cope with emergency situations where the results need to be known within a few hours, it is required to improve the performance of a single genome analysis. In this paper, we propose a parallelized method for pre-processing genome sequence data which can reduce the analysis time by utilizing the big data technology and the highperformance computing cluster which is connected to the high-speed network and shares the parallel file system. For the reliability of analytical data, we have chosen a strategy to parallelize the existing analytical tools and algorithms to the new environment. Parallelized processing, data distribution, and parallel merging techniques have been developed and performance improvements have been confirmed through experiments.

• Research in Plant Disease
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• v.26 no.4
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• pp.202-209
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• 2020

Organic farming is necessary to sustainable agriculture, preserve biodiversity and continued growth the sector in agriculture. In organic farming, reduced usage of chemical agents that adversely affect human health and environment, employing amino acids and oil cake fertilizer, plant extracts, and microbial agents are used to provide safe agricultural products to consumers. To investigation microbiome structure, we proceeded on the pepper plant with difference fertilizers and treatments in organic agriculture for three years. The microbial communities were analyzed by the next generation sequencing approach. Difference soil microbiota communities were discovered base on organic fertilizer agents. Occurrences of virus and anthracnose diseases had a low incidence in conventional farming, whereas bacteria wilt disease had a low incidence in microbial agents treated plots. Microbe agents, which applied in soil, were detected in the microbial community and the funding suggested the applied microbes successfully colonized in the organic farming environment.

• The Korean Journal of Applied Statistics
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• v.34 no.2
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• pp.153-166
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• 2021

A main goal of pharmacogenomics studies is to predict individual's drug responsiveness based on high dimensional genetic variables. Due to a large number of variables, feature selection is required in order to reduce the number of variables. The selected features are used to construct a predictive model using machine learning algorithms. In the present study, we applied several hybrid feature selection methods such as combinations of logistic regression, ReliefF, TurF, random forest, and LASSO to a next generation sequencing data set of 400 epilepsy patients. We then applied the selected features to machine learning methods including random forest, gradient boosting, and support vector machine as well as a stacking ensemble method. Our results showed that the stacking model with a hybrid feature selection of random forest and ReliefF performs better than with other combinations of approaches. Based on a 5-fold cross validation partition, the mean test accuracy value of the best model was 0.727 and the mean test AUC value of the best model was 0.761. It also appeared that the stacking models outperform than single machine learning predictive models when using the same selected features.