• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.318-325
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• 2021

The objective of this study was to identify the effect of zebularine, a DNA methylation inhibitor, on the chromosomal association between homoeologous chromosomes in the wheat genetic background. Zebularine at a final concentration of 10 µM was used to treat the spikes of the double monosomic wheat addition line (DMA) with one Leymus mollis chromosome and one Leymus racemosus chromosome, both of which were in a homoeologous relationship. In late prophase, zebularine led to chromosome breakage in the Leymus homoeologous chromosomes. Chromosome breakage caused an increase in the frequency of chromosomal associations between the Leymus homoeologous chromosomes. Ordinary DMA showed 65 cells (35.3%) with chromosomal associations and 119 cells (64.7%) with no association, whereas treated DMA showed 102 cells (60.0%) with chromosomal associations and 67 cells (39.4%) with no association. In diakinesis, the Leymus bivalent showed a chromosomal association in the whole euchromatic region. In metaphase, the Leymus bivalent showed association in the whole chromosomal region, unlike other Leymus bivalents with partial chromosomal association. Chromosomal association by chromosome breakage occurred not only between Leymus chromosomes but also between Leymus and wheat chromosomes. The frequency of other chromosomal association (such as fusion and insert) was increased. Chromosome breakage by zebularine treatment is a useful method at the chromosome level as the spores with others are hereditary stable, although the homologous index (h) was not significantly different between ordinary DMA and treated DMA. It is necessary to study how to control zebularine treatment with a more stable concentration for chromosome breakage during meiosis.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.31-39
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• 2007

This study has been carried out for investigating the relatedness of representative 135 Shigella sonnei strains isolated from 2000 to 2004 by using biotyping and antimicrobial resistance. All strains showed typical biochemical characterisics of Shigella strain. Among 135 strains,79 (58.5%) strains were biotype "g",54 (40.0%) strains were biotype "a" and 2 (1.5%) strains were biotype "e". The results of susceptibility test against 16 antimicrobial agents were like this. Most of strains were susceptible to AN, CIP, C and GM. 129 (95.6%) strains were resistant to SXT, 126 (93.3%) strains were resistant to TE and 122 (90.4%) strains were resistant to SM. One hundred thirty two (97.8%) strains were resistant to more than two antimicrobial agents. R28 type (antimicrobial resistance patterns 28: resistant to AM, SAM, TE, TIC, SXT, K, SM and AmC) were 42 strains (31.1%). The other strains were showed 33 kinds of R patterns. The results of $bla_{TEM}$, sulII, tetA and strA gene detection were coincided with phenotype of antimicrobial resistance by disk diffusion method. But some strains which had sulII and strA genes were not showed the resistance against SXT and SM.

• Journal of Life Science
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• v.16 no.4
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• pp.664-671
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• 2006

We obtained 424 Salmonella enterica serovar Typhi isolates from sporadic cases of infection in Busan during 1996 to 2005. We investigated the trend of antimicrobial resistance and molecular typing by pulsed-field gel electrophoresis (PFGE). Of the total 424 isolates, 6 strains (1.4%) were multidrug-resistant (MDR) S. enterica serovar Typhi isolates, 2 strains (0.5%) were resistant to only nalidixic acid, and the remaining 416 strains (98.1%) were fully susceptible to the 18 antimicrobial agent. PFGE of XbaI-digested chromosomal DNA was performed on 50 sporadic S. enterica serovar Typhi isolates with the objective of investigating the extent of genetic diversity of these isolates in our region. We could find that these isolates were much more heterogeneous and at least 32 different PFGE patterns were generated according by dice coefficient, between 0.69 and 1.0. Restriction fragment patterns consisted of 13 to 18 fragments ranged in size from 20 to 630 kb. The results confirmed that PFGE would be an useful tool for investigating surveillance of sporadic or outbreak case and assessing clonality for S. enterica serovar Typhi in Busan area. Our finding will be valuable in developing rational strategies to control this pathogen and setting the basis of an effective PulseNet system in Korea.

• Korean Journal of Biological Psychiatry
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• v.15 no.4
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• pp.275-287
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• 2008

Depression and coronary artery disease are both highly prevalent diseases. Many previous studies suggest that depression is a common comorbid condition in patients with coronary artery disease and has a significant negative impact on the onset, course, and prognosis of coronary artery disease. However, the exact mechanisms that underlie the association between these two diseases remain unclear. Pathophysiologic mechanisms that may explain the effect of depression on coronary artery disease include hypercoagulability, hypothalamus-pituitary-adrenal axis and autonomic nervous system dysregulation, altered inflammatory response. On the contrary, pathophysiologic mechanisms in coronary artery disease that affect depression are less well known. It is also suggested that both diseases may share a common genetic vulnerability. The authors reviewed the literature on the pathophysiologic relationships of depression and coronary heart disease.

• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.467-487
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• 2020

Anatomical imaging is the basis of the diagnosis and treatment response assessment of brain tumors. Among the existing imaging techniques currently available in clinical practice, diffusion-weighted imaging and perfusion imaging provide additional information. Recently, with the increasing importance of evaluation of the genomic variation and heterogeneity of tumors, clinical application of imaging techniques using radiomics and deep learning is expected. In this review, we will describe recommendations for magnetic resonance imaging protocols focusing on anatomical images that are still important in the clinical application of brain tumor imaging, and the basic principles of diffusion-weighted imaging and perfusion imaging among the advanced imaging techniques, as well as their pathophysiological background and clinical application. Finally, we will review the future perspectives of radiomics and deep learning applications in brain tumor imaging, which have been studied to a great extent due to the development of computer technology.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.89-89
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• 2018

우리나라, 중국 및 일본을 포함한 동북아시아가 원산이며 바이오매스량이 많은 억새(Miscanthus spp.)는 바이오에너지 생산을 위한 원료작물로서 가치가 높아, 바이오에탄올 생산용 원료작물로 주목을 받고 있다. 독일 등 유럽과 미국에서는 바이오에탄올 생산용 작물로 주로 종간 교잡 이질 3배체인 불임성 억새(M. x giganteous)를 대상으로 연구하고 있다. 이렇게 단일유전형을 갖는 품종의 재배에는 특정 병과 해충에 약하며 자연재해에도 취약성을 나타내므로 억새가 바이오에너지작물로 자리 잡기 위해서는 다양한 유전형의 억새 품종 개발이 필요하다. 본 연구는 우리나라의 자생 억새 3종을 기내배양하고 탈분화 및 재분화 시스템을 구축하여 억새 품종 육성 시 효율을 높이기 위해서 실시하였다. 억새 종자로부터 캘러스의 유도는 MS배지보다 N6배지 에서 좋았으며, 식물생장조절제로 2,4-Dichlorophenoxyacetic acid (2,4-D)와 6-Benzyl aminopurine (BA)를 조합처리한 처리구보다 2,4-D만을 단독처리하였을 때 캘러스 유도율이 더 높았다. 억새 종에 따른 캘러스 유도율은 물억새가 가장 낮고, 거대억새가 가장 높았으며, 3 ~ 5 mg/L의 2,4-D가 첨가된 N6배지에서 배발생 캘러스(embryogenic callus)가 발생하였다. 억새 신초 및 줄기의 절간에서의 캘러스 유도율은 전반적으로 종자에 비하여 낮았으며, 미성숙화기로부터의 캘러스 유도는 억새 종에 따른 차이가 없었으며, 5mg/L의 2,4-D가 첨가된 배지에서 캘러스 유도율이 가장 높게(90 ~ 95%) 나타났다. 형성된 배발생 캘러스로부터 식물체의 재분화는 N6배지에서는 재분화 식물체가 발생하지 않았고, 1 ~ 3mg/L의 BA와 0.1ml/L의 1-Naphthaleneacetic acid (NAA)가 첨가된 MS배지에서만 식물체가 재분화되였다.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.161-167
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• 2015

Sweetpotato [Ipomoea batatas (L.) Lam] grows well in harsh environmental conditions, and is cultivated as one of the top seven food crops in the world. Recently, sweetpotato is drawing interest from people as a healthy food because it is high in dietary fiber, vitamins, carotenoids and overall nutrition value. However, few studies have been conducted on sweetpotato genome sequencing in spite of its importance. This review is aimed at increasing the efficiency of sweetpotato genome sequencing research as well as establishing a base for gene utilization in order to control useful traits. Recently, animal and plant genome sequencing projects increased significantly. However, sweetpotato genome sequencing has not been performed due to polyploidy and heterogeneity problems in its genome. Meanwhile research on its transcriptome has been conducted actively. Recently, a draft of the diploid sweetpotato genome was reported in 2015 by Japanese researchers. In addition, the Korea-China-Japan Trilateral Research Association of Sweetpotato (TRAS) has conducted research on gene map construction and genome sequencing of the hexaploid sweetpotato Xushu 18 since 2014. The Bill & Melinda Gates Foundation launched the 'sweetpotato genomic sequencing to develop genomic tools for Sub-Sahara Africa breeding program'. The chloroplast genome sequence acquired during sweetpotato genome sequencing is used in evolutionary analyses. In this review, the trend of research in the sweetpotato genome sequencing was analyzed. Research trend analysis like this will provide researchers working toward sweetpotato productivity and nutrient improvement with information on the status of sweetpotato genome research. This will contribute to solving world food, energy and environmental problems.

• Journal of Plant Biotechnology
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• v.47 no.2
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• pp.141-149
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• 2020

Solanum hougasii, one of the wild Solanum species, has been widely used in potato breeding since it exhibits excellent resistance to diverse important pathogens. S. hougasii can be directly crossed with the cultivated tetraploid potato (S. tuberosum) owing to its EBN (Endosperm Balanced Number) value of 4, which is same as that of S. tuberosum although it is an allohexaploid. In this study, the complete chloroplast genome sequence of S. hougasii was obtained by next-generation sequencing technology, and compared with that of the chloroplast genome of seven other Solanum species to identify S. hougasii-specific PCR markers. The length of the complete chloroplast genome of S. hougasii was 155,549 bp. The structural organization of the chloroplast genome in S. hougasii was found to be similar to that of seven other Solanum species studied. Phylogenetic analysis of S. hougasii with ten other Solanaceae family members revealed that S. hougasii was most closely related to S. stoloniferum, followed by S. berthaultii, and S. tuberosum. Additional comparison of the chloroplast genome sequence with that of five other Solanum species revealed five InDels and 43 SNPs specific to S. hougasii. Based on these SNPs, four PCR-based markers were developed for the differentiation of S. hougasii from other Solanum species. The results obtained in this study will aid in exploring the evolutionary and breeding aspects of Solanum species.

• Journal of Ginseng Culture
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• v.3
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• pp.1-10
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• 2021

Panax ginseng (Ginseng or Korean ginseng) is one of the most important medicinal herbs in the world. We made a high-quality whole genome sequence of P. ginseng using 'Chunpoong' cultivar, which is the first cultivar registered in Korea Seed and Variety Service (KSVS) with relatively similar genotypes and superior phenotypes, representing approximately 3 Gbp and 60,000 genes. Genome sequence analyses of P. ginseng and related speciesrevealed the origin of Korean ginseng and the ecological adaptation of 18 Panax species around the world. Korean ginseng and American ginseng (P. quinquefolius) are tetraploid species having 24 chromosome pairs, while the other 16 species are diploid species with 12 chromosome pairs. Panax and Aralia are the closest genera belonging to the Araliaceae family that diverged approximately 8 million years ago (MYA). All Panax species evolved as shade plants adapting to cool climates and low light conditions under the canopy of deep forests from Southeast Asia such as Vietnam to Northeast Asia such as Russia approximately 6 MYA. However, through recurrent ice ages and global warming, most diploid Panax species disappeared due to the freezing winter, while tetraploid P. ginseng may have appeared by allotetraploidization, which contributed to the adaptation to cold temperaturesin Northeast Asian countries including the Korea peninsula approximately 2 MYA. American ginseng evolved by the adaptation of P. ginseng in Northeast America after the intercontinental migration 1 MYA. Meanwhile, most of diploid Panax species survived in high-altitude mountains over 1,600 meters in Southeast Asia because they could not endure the hot temperature and freezing cold. The genome sequence provides good basisto unveil the origin and evolution of ginseng and also supports practical gene chips which is useful for breeding and the ginseng industry.

• Journal of Mushroom
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• v.2 no.3
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• pp.115-126
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• 2004

Somatic hybrids of inter-compatible and inter-incompatible strains were obtained by protoplast fusion. The fusion products between compatible strains, Pleurotus ostreatus and P. florida, formed heterokaryons, while fusants between incompatible strains such as P. cornucopiae + P. florida, P. ostreatus + Ganoderma applanatum, P. florida + Ganoderma lucidum, and P. ostreatus + Flammulina velutipes formed synkaryons that retained genes from both parents. The heterokaryons showed the same level of basidioma development. In contrast, the synkaryons showed unique characteristics including clamp connection formation at mitosis, either partner basidioma development, and abnormal segregation and recombination compared with inter-compatible strains. Synkaryons can be classified into homokaryoyic and heterokaryotic type. A comparison of somatic hybrids with compatible and incompatible strains was made using random amplified polymorphic DNA (RAPD) analysis. The heterokaryons between compatible species showed the same level of variability and contained both parental RAPD bands. In contrast, most of the synkaryons between incompatible species showed similarity to those of either parental bands and non-parental RAPD bands. Synkaryons can be classified into microgenome insertion type and macrogenome insertion type. A tetrapolar mating system was found among monospore isolates in somatic hybrids and wild type P. ostreatus. Homokaryons from each somatic hybrid combination were paired with tester homokaryons of the initial wild type of P. ostreatus. The changed mating types were identified in progenies. The pattern of mating type switching in somatic hybrids depends on compatibility of fusion partner. There are several factors related to the mechanism of clamp connection formation and fruiting body development of synkaryons. Of these,the major factor may be associated with self-fertility and mating type switching such as homokaryotic fruiting of wild type P. ostreatus. This review will discuss these aspects.