• Journal of Life Science
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• v.27 no.7
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• pp.746-753
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• 2017

In order to rapidly identify four drums species, Larimichthys polyactis, L. crocea, Atrobucca nibe, and Pseudotolithus elongates, a highly efficient and quick method has been developed using multiplex polymerase chain reaction (PCR) with species-specific primers. Around 1.4 kbp of the mitochondrial COI gene sequences from the four drums species were aligned, and species-specific forward primers were designed, based on the single nucleotide polymorphism (SNP). The optimal conditions for PCR amplification were selected through cross-reactivity, using a gradient PCR method. The PCR results demonstrated species-specific amplification for each species at annealing temperatures between 50 and $62^{\circ}C$. Multiplex species-specific PCR (MSS-PCR) amplification reactions with four pairs of primers were performed for sixteen specimens of each species. MSS-PCR lead to a species-specific amplification of a 1,540 bp fragment in L. polyactis, 1,013 bp in A. nibe, 474 bp in L. crocea, and 182 bp in P. elongates, respectively. The four different sizes of each PCR product can be quickly and easily detected by single gel electrophoresis. The sensitivity of the MSS-PCR of the DNA was up to $0.1ng/{\mu}l$ as a starting concentration for the four different species tested. These results suggest that MSS-PCR, with species-specific primers based on SNP, can be a powerful tool in the rapid identification of the four drums species, L. polyactis, L. crocea, A. nibe, and P. elongates.

• Journal of Korean Society of Forest Science
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• v.102 no.1
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• pp.59-65
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• 2013

The jujube is an important fruit tree species in Korea. Traditionally, classifications of jujube cultivars have been based on morphological characters; however, morphological identification can be problematic because morphological traits are affected by environmental conditions. Therefore, DNA markers are now being used for the rapid and accurate identification of plant species. Inter-simple sequence repeat (I-SSR) is one of the best DNA-based molecular marker techniques, which is useful for studying genetic relations and for the identification of closely related cultivars. In this study, 5 Korean jujube trees and 1 jujube tree imported from China were analyzed for 16 I-SSR primers. Amplification of the genomic DNA of jujube cultivars by using I-SSR analysis generated 100 bands, with an average of 6.25 bands per primer, of which 45 bands (45%) were polymorphic. The number of amplified fragments with I-SSR primers ranged from 2 to 13. The percentage of polymorphism ranged from 10% to 100%. I-SSR finger printing profiles showed that 'Boeun jujube' and 'Daeri jujube' had characteristic DNA patterns, indicating unequivocal cultivar identification at molecular level. According to the results of clustering analysis, the genetic similarity coefficient ranged from 0.68 to 0.92. 'Boeun jujube' and 'Daeri jujube' were divided into independent groups, and 'Bokjo jujube', 'Geumseong jujube', 'Wolchul jujube', and 'Mudeung jujube' were placed in the same group. Therefore, I-SSR markers are suitable for the discrimination of 'Boeun jujube' and 'Daeri jujube' cultivars.

• Genomics & Informatics
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• v.10 no.3
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• pp.175-183
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• 2012

Colorectal cancer (CRC) is among the leading causes of cancer deaths and can be caused by environmental factors as well as genetic factors. Therefore, we developed a prediction model of CRC using genetic risk scores (GRS) and evaluated the effects of conventional risk factors, including family history of CRC, in combination with GRS on the risk of CRC in Koreans. This study included 187 cases (men, 133; women, 54) and 976 controls (men, 554; women, 422). GRS were calculated with most significantly associated single-nucleotide polymorphism with CRC through a genomewide association study. The area under the curve (AUC) increased by 0.5% to 5.2% when either counted or weighted GRS was added to a prediction model consisting of age alone (AUC 0.687 for men, 0.598 for women) or age and family history of CRC (AUC 0.692 for men, 0.603 for women) for both men and women. Furthermore, the risk of CRC significantly increased for individuals with a family history of CRC in the highest quartile of GRS when compared to subjects without a family history of CRC in the lowest quartile of GRS (counted GRS odds ratio [OR], 47.9; 95% confidence interval [CI], 4.9 to 471.8 for men; OR, 22.3; 95% CI, 1.4 to 344.2 for women) (weighted GRS OR, 35.9; 95% CI, 5.9 to 218.2 for men; OR, 18.1, 95% CI, 3.7 to 88.1 for women). Our findings suggest that in Koreans, especially in Korean men, GRS improve the prediction of CRC when considered in conjunction with age and family history of CRC.

• Genomics & Informatics
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• v.16 no.3
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• pp.52-58
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• 2018

In this report, we present a case study of how pharmacogenomics and pharmacometabolomics can be useful to characterize safety and pharmacokinetic profiles in early phase new drug development clinical trials. During conducting a first-in-human trial for a new molecular entity, we were able to determine the mechanism of dichotomized variability in plasma drug concentrations, which appeared closely related to adverse drug reactions (ADRs) through integrated omics analysis. The pharmacogenomics screening was performed from whole blood samples using the Affymetrix DMET (Drug-Metabolizing Enzymes and Transporters) Plus microarray, and confirmation of genetic variants was performed using real-time polymerase chain reaction. Metabolomics profiling was performed from plasma samples using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. A GSTM1 null polymorphism was identified in pharmacogenomics test and the drug concentrations was higher in GSTM1 null subjects than GSTM1 functional subjects. The apparent drug clearance was 13-fold lower in GSTM1 null subjects than GSTM1 functional subjects (p < 0.001). By metabolomics analysis, we identified that the study drug was metabolized by cysteinylglycine conjugation in GSTM functional subjects but those not in GSTM1 null subjects. The incidence rate and the severity of ADRs were higher in the GSTM1 null subjects than the GSTM1 functional subjects. Through the integrated omics analysis, we could understand the mechanism of inter-individual variability in drug exposure and in adverse response. In conclusion, integrated multi-omics analysis can be useful for elucidating the various characteristics of new drug candidates in early phase clinical trials.

• Tuberculosis and Respiratory Diseases
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• v.50 no.2
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• pp.229-235
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• 2001

Background : Alpha-1-antitrypsin (A1AT) deficiency is the only established genetic risk factor for emphysema. This study was undertaken to investigate the prevalence of the genotypes of A1AT genotypes in healthy Koreans. Method : The study population consisted of 380 Healthy Koreans enrolled at the Health Promotion Center in Kyungpook National University Hospital. The polymerase chain reaction (PCR) and restriction fragment length polymorphim (RFLP) for detecting the A1AT variants M1(Ala), M1(Val), M2, S and Z were used. Results : The genotypes of subjects were as follows : M1(Val)/M1(Val), 254(66.8%) ; M1(Val)/M2, 105(27.6%) ; M2/M2, 19 (5.0%) ; and M1(Val)/M1(Ala), 2 (0.5%). There was no case with 'deficiency' alleles such as S and Z found in this study. Conclusion : These results suggest that A1AT deficient alleles are either extremely rare or not present in Koreans.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.308-314
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• 2000

Background : DNA fingerprinting of Mycobacterium tuberculosis with RFLP is a very useful tool for deciphering the molecular epidemiology of tuberculosis. An international comparison of the RFLP pattern became possible with the proposal to standardize RFLP methodology using Pvu-II restricted IS-6110, and the comparison has noted some predominance of RFLP pattern in East Asia. The RFLP patterns of tuberculosis strains collected at SNUH was studied and was compared with other strains from East Asia. Method : Fifty strains of M. tuberculosis were isolated from patients who visited 'or were admitted to the SNUH in 1998. Some isolates belonging to the Beijing family were also received. After the extraction of DNA from M. tuberculosis isolates, the chromosomal DNAs were digested with Pvu-II and analyzed by the Southern blot method with DNA probe to IS6110. Result : Six strains belonged to the Beijing family. The RFLP patterns of other 9 strains were similar to each other. No statistically significant endobronchial tuberculosis, presence of underlying disease. and the province of residence were found. Conclusion : Few groups of M. tuberculosis strains from SNUH showed similar RFLP patterns, but their clinical implications are not yet clear.

• 한국균학회소식:학술대회논문집
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• 2015.11a
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• pp.41-41
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• 2015

Oomycetes belong to the kingdom Straminipila, a remarkably diverse group which includes brown algae and planktonic diatoms, although they have previously been classified under the kingdom Fungi. These organisms have evolved both saprophytic and pathogenic lifestyles, and more than 60% of the known species are pathogens on plants, the majority of which are classified into the order Peronosporales (includes downy mildews, Phytophthora, and Pythium). Recent phylogenetic investigations based on DNA sequences have revealed that the diversity of oomycetes has been largely underestimated. Although morphology is the most valuable criterion for their identification and diversity, morphological species identification is time-consuming and in some groups very difficult, especially for non-taxonomists. DNA barcoding is a fast and reliable tool for identification of species, enabling us to unravel the diversity and distribution of oomycetes. Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The mitochondrial cox2 gene has been widely used for identification, taxonomy and phylogeny of various oomycete groups. However, recently the cox1 gene was proposed as a DNA barcode marker instead, together with ITS rDNA. To determine which out of cox1 or cox2 is best suited as universal oomycete barcode, we compared these two genes in terms of (1) PCR efficiency for 31 representative genera, as well as for historic herbarium specimens, and (2) in terms of sequence polymorphism, intra- and interspecific divergence. The primer sets for cox2 successfully amplified all oomycete genera tested, while cox1 failed to amplify three genera. In addition, cox2 exhibited higher PCR efficiency for historic herbarium specimens, providing easier access to barcoding type material. In addition, cox2 yielded higher species identification success, with higher interspecific and lower intraspecific divergences than cox1. Therefore, cox2 is suggested as a partner DNA barcode along with ITS rDNA instead of cox1. Including the two barcoding markers, ITS rDNA and cox2 mtDNA, the multi-locus phylogenetic analyses were performed to resolve two complex clades, Bremia lactucae (lettuce downy mildew) and Peronospora effuse (spinach downy mildew) at the species level and to infer evolutionary relationships within them. The approaches discriminated all currently accepted species and revealed several previously unrecognized lineages, which are specific to a host genus or species. The sequence polymorphisms were useful to develop a real-time quantitative PCR (qPCR) assay for detection of airborne inoculum of B. lactucae and P. effusa. Specificity tests revealed that the qPCR assay is specific for detection of each species. This assay is sensitive, enabling detection of very low levels of inoculum that may be present in the field. Early detection of the pathogen, coupled with knowledge of other factors that favor downy mildew outbreaks, may enable disease forecasting for judicious timing of fungicide applications.

• The Korean Journal of Mycology
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• v.37 no.1
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• pp.19-27
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• 2009

This study was conducted to investigate genetic characteristics of 25 Pleurotus eringii strains that have been released in Korea based on cultural, morphological features and PCR fingerprints. Strains PER-007 and PER-012 showed distinct cultural characteristics in growth rate, morphological characteristics of mycelial colony and fruiting bodies when compared to those of other strains. Strain PER-007 did not form primordium initiation in sawdust medium and PER-012 also showed different phenotypes on fruiting bodies. Eleven URP primers were used to detect PCR polymophic bands in P. eringii strains. Primers URP1F, URP2R, URP2F, URP4R, URP6R, URP9F and URP17R were selected as useful primers for amplifying PCR polymorphic bands in P. eringii strains. The genetic similarity index was calculated by using PCR polymorphic bands amplified by eight URP primers among the 25 strains. The P. eringii strains were grouped by four distinct clusters on the UPGMA analysis. The genetic similarity values ranged from 100% to 76% were observed in three major groups, suggesting close genetic relatedness of them. Exceptionally, PER-007 and PER-017 were involved in outgroup.

• Korean Journal of Plant Taxonomy
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• v.41 no.2
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• pp.119-129
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• 2011

Phylogenetic studies were conducted to evaluate the taxonomic relationships among 27 taxa, including 2 outgroups of Korean Campanulaceae, using PCR-RFLP analysis and ITS sequences. In the PCR-RFLP analysis, 15 restriction endonucleases produced 244 restriction sites and size variations from the chloroplast DNA, and 59 restriction sites (24%) showed polymorphism. The length of the ITS regions ranged from 588 bp to 797 bp. The sequence divergence including the outgroups is 0-39.36%. Phylogenetic analyses based on PCR-RFLP and ITS data suggest that Campanulaceae is monophyletic; Codonopsis and Platycodon forms an independent clade; the Peracarpa and Asyneuma clade is a sister to the Adenophora-Hanabusaya clade; Campanula is monophyletic; and Wahlenbergia basally branches within the ITS tree, whereas they are placed between Campanula and the Codonopsis-Platycodon clade in the PCR-RFLP tree; Hanabusaya is placed within the Adenophora clade; and Adenophora is paraphyletic and shows discordance to the infrageneric classifications based on morphological data. The present results show two data sets, largely congruent at the generic level, but their phylogenetic positions, in particular the Wahlenbergia and Hanabusaya and the infrageneric classifications in Adenophora, show some incongruence.

• Korean Journal of Plant Taxonomy
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• v.47 no.4
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• pp.297-303
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• 2017

In central and southern Korea, the two small insectivorous, terrestrial herbs, Utricularia bifida and U. caerulea, often co-occur at wet locations (or in wetlands). The Korean Peninsula (with central China and northern Japan) constitutes the northern edge of their distribution, as their main range is subtropical and tropical Asia. The Korean populations of both species are very likely of post-glacial origin, given that warm-temperate vegetation was absent from the Korean Peninsula during the Last Glacial Maximum. Two hypotheses of the post-glacial colonization of the peninsula can be formulated; first, if current populations were founded by propagules coming from a single ancestral population (i.e., a single refugium), we would expect low levels of genetic diversity. Alternatively, if contemporary Korean populations originated from multiple sources (multiple refugia), we would expect high levels of genetic variation. To test which is more likely, we surveyed the degree of allozyme variation at 20 loci in ten populations for each of the two species from southern Korea. We found no allozyme variation within each species. However, their aquatic congener U. australis exhibited allozyme polymorphism across Japan (four polymorphic loci at three enzyme systems). We suggest that southern Korean populations of Utricularia bifida and U. caerulea were established by a single introduction event from a genetically depauperate ancestral population.