• Journal of Plant Biotechnology
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• v.50
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• pp.248-254
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• 2023

This study was conducted to establish an efficient plant regeneration system in 'Dayu', a Korean variety of Perilla frutescens developed for seed oil production, in conjunction with the previously studied variety 'Namcheon'. The healthiest callus was formed on the hypocotyl explants cultured on a medium containing 0.1 mg/L NAA and 0.5 mg/L BA, outperforming the leaf and cotyledon samples. In both dark and long-day conditions, Dayu consistently exhibited significantly higher shoot regeneration rates compared with Namcheon. The highest shoot regeneration rates in Dayu were observed from the hypocotyl explants cultured on 0.1 mg/L NAA and 0.5 mg/L BA media, with shoot regeneration rates of 84.4% and 86.7% under dark and long-day conditions, respectively. Various combinations of plant growth regulators were tested to establish the optimal shoot regeneration conditions for Dayu hypocotyl explants. The results demonstrated that the highest shoot regeneration rate (90%) was achieved when 0.5 mg/L of BA was added to the medium without NAA. Among the regenerated shoots, 70.5% were normal plants, while 19.3% were abnormal. The addition of NAA or an increase in its concentration led to a higher occurrence of abnormal plants. After the regenerated shoots were transferred to 1/2 MS medium, roots were observed within 10-15 days. By day 30, they had developed into complete plants. The results obtained from the regeneration experiments with the perilla variety Dayu can valuably inform molecular breeding reliant on transformation techniques such as genome-editing and genetic modification technology.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.8
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• pp.1186-1193
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• 2015

This study was performed to investigate the changes in monacolin K content and antioxidant activities of Monascus-fermented brown rice with different germination temperatures and periods. Brown rice was germinated at 32, 35 and $37^{\circ}C$ for 1~4 days, after white rice (WB), brown rice (BR), and germinated brown rice (GBR) were fermented with M. pilosus 305-9 at $30^{\circ}C$ for 20 days. The redness, yellowness and Monascus pigments increased after germination. Total monacolin K content increased from 215.85 mg/kg of BR to 1,263.04 mg/kg of GBR ($32^{\circ}C$/1 day), whereas monacolin K content decreased with increase in germination period. Citrinin was not detected in any of the samples. Total polyphenol (TPC) and flavonoid contents (TFC) increased with increase in germination temperature and period, whereas electron donating ability (EDA) and total antioxidant activities (TAA) decreased due to reduction of Monascus pigment content. The TPC and TFC showed the highest values (13.80 mg/g and 1.30 mg/g, respectively) in GBR ($37^{\circ}C$/4 day), whereas EDA and TAA showed the highest values (22.16 mg Trolox equivalent/g and 62.27 mg ascorbic acid equivalent/g, respectively) in GBR ($32^{\circ}C$/1 day). These results indicated that the optimal germination temperature and period for increasing monacolin K content and antioxidant activities was found to be at $32^{\circ}C$ for 1 day. In addition, it was found that M. pilosus 305-9 was a useful strain for increasing monacolin K content without producing citrinin in functional foods and pharmaceutical industrial regions.

• Korean Journal of Plant Taxonomy
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• v.46 no.2
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• pp.256-266
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• 2016

A total of 13,000 individuals of Dendrobium moniliforme (L.) Sw. artificially propagated in laboratories and greenhouses were restored in their natural habitat of Bogildo Island, Wandogun, in the southern part of Korea in June of 2013. The growing conditions of the individuals were monitored for two years. The parental individuals for the restoration were obtained from a wild population in southern Korea, from which seeds were produced via artificial crossings. These seeds were germinated and cultivated in growing media and two-year-old plants were then grown in greenhouse beds. The genetic diversity among the propagated individuals was confirmed by examining DNA sequences of five regions of the chloroplast genome and the nuclear ITS region. The diversity values were as high as the average values of natural populations. All propagated individuals were transplanted into two different sites on Bogildo by research teams with local residents and national park rangers. After restoration, we counted and measured the surviving individuals, vegetative propagated stems, and growth rates in June of both 2014 and 2015. There was no human interference, and 97% of the individuals survived. The number of propagules increased by 227% in two years. In contrast, the average length of the stems decreased during the period. In addition, different survival and propagation rates were recorded depending on the host plants and the restored sites. The shaded sides of rock cliffs and the bark of Quercus salicina showed the best propagation rates, followed by the bark of Camellia japonica. A few individuals of D. moniliforme successfully flowered, pollinated, and fruited after restoration. Overall, our monitoring data over two years indicate that the restored individuals were well adapted and vigorously propagated at the restored sites. In order to prevent human disturbance of the restored sites, a CCTV monitoring system powered by a solar panel was installed after the restoration. In addition, a human surveillance system is operated by national park rangers with local residents.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.1-35
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• 1997

Fertilized egg, by successive cell divisions, differentiates into different tissues and organs with various structures and functions. Different cells and tissues contain different proteins, products of selective gene expression. Not all the genes in any genomes are equally active, temporal and spatial gene expression being the general rule. Present paper attempts to review the tanscriptional mechanisms or the initiations of transcription from several angles. In some of the organisms the genes in the process of transcription or the genes in the inactive state can be seen under the light microscope. Some bands of Drosophila polytene chromosomes may exhibit a swollen or puff appearance under certain conditions. A puff, unfolded or decondensed form of chromomere, represents sets of intense transcriptional activity or RNA synthesis. The heterochromatic X chromosome whose genes remain inactive in the female mammals can be visualized as a dark staining structure called Barr body, Configuration of chromatin differs between transcribed and nontranscribed chromatin. Modification to the chromatin facilitates RNA synthesis. The movement of large polymerase molecule along the DNA would probably be facilitated if some modifications of the chromatin configuration is effected. Methylation of cytosines in CG sequences is associated with inactive genes. Methylation can play a role in determination of mammalian cells during embryogenesis. Demethylation is necessary for the gene to be expressed during development A histone modification that is also known to be correlated with transcriptional capacity of chromatin is acetylation of the lysine residues of the core histones. Chromatin containing a high level of histone acetylation is very sensitive to DNase 1. For the transcription to occur TBP must first bind to the TATA box. Another TF, TF IIB, then binds to the promoter-TBP complex, facilitating the access of RNA polymerase to the transcription initiation site. As recently as eight years ago researchers assumed that histones were irrelevant to the regulation of gene expression. Histones combine with the DNA to form nucleosome of the chromatin. Histones are vital participant in gene regulation. Histone and basal factors compete for access to TATA box. When DNA is exposed to basal factors before histones are introduced, the basal factors assemble on TATA boxes preventing the access of histones, allowing transcription to occur, for transcription to begin, activator protein at the upstream activation sequence or enhancer must interact with the tail of histone H4 at TATA box and cause the histone role particle to dissociate from the TATA box leading to partial breakup of the histone core particle and allowing the basal factors to bind to the TATA box. New concept of genomic flux in contrast to the old concept of static genome has been developed based on the powerful new molecular techniques. Genomic changes such as repetitive DNAs and transposable elements, it is assumed but not yet proved, may affect some of the developmental patterns that characterize particular cells, tissues, organs, and organisms. In the last decade or so remarkable achievement have been made in the researches of the structures and functions of TFs and the specific target sequences located in promoters or enhancers where these TFs bind. TFs have independent domains that bind DNA and that activate transcription. DNA binding domain of TFs serves to bring the protein into the right location. There are many types of DNA binding domains. Common types of motifs can be found that are responsible for binding to DNA. The motifs are usually quite short and comprise only a small part of the protein structure. Steroid receptors have domains for hormone binding, DNA binding, and activating transcription. The zinc finger motif comprises a DNA binding domain. Leucine zipper consist of a stretch of amino acids with a leucine residue in every seventh position Two proteins form a dimer because they interact by means of leucine zippers on similar α-helical domain. This positions their DNA binding basic domains for interaction with the two halves of a DNA sequence with dyad symmetry of TGACTCA, ACTGAGT.

• Research in Plant Disease
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• v.19 no.4
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• pp.254-258
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• 2013

Fusaric acid (FA) is a mycotoxin produced by Fusarium species. Its toxicity is relatively low but often associated with other mycotoxins, thus enhancing total toxicity. To date, biosynthetic genes or enzymes for FA have not been identified in F. oxysporum. In order to explore the genetic element(s) for FA biosynthesis, restriction enzyme mediated integration (REMI) procedure as an insertional mutagenesis was employed using FA producing-F. oxysporum strains. Genetic transformation of two F. oxysporum strains by REMI yielded more than 7,100 transformants with efficiency of average 3.2 transformants/${\mu}g$ DNA. To develop a screening system using phytotoxicity of FA, eleven various grains and vegetable seeds were tested for germination in cultures containing FA: Kimchi cabbage seed was selected as the most sensitive host. Screening for FA non-producer of F. oxysporum was done by growing each fungal REMI transformant in Czapek-Dox broth for 3 weeks at $25^{\circ}C$ then observing if the Kimchi cabbage seeds germinated in the culture filtrate. Of more than 5,000 REMI transformants screened, fifty-three made the seeds germinated, indicating that they produced little or fewer FA. Among them, twenty-six were analyzed for FA production by HPLC and two turned out to produce less than 1% of FA produced by a wild type strain. Sequencing of genomic DNA regions (252 bp) flanking the vector insertion site revealed an uncharacterized genomic region homologous (93%) to the F. fujikuroi genome. Further study is necessary to determine if the vector insertion sites in FA-deficient mutants are associated with FA production.

• Clinical and Experimental Pediatrics
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• v.51 no.9
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• pp.964-970
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• 2008

Purpose : Methylmalonic aciduria (MMA) and propionic aciduria (PA) are inborn errors in the catabolism of branched-chain amino acids. The study was undertaken to investigate the genotypes and clinical features of Korean patients with MMA and PA. Methods : This study examined 12 patients with MMA and eight with PA. We analyzed various clinical features, laboratory findings, treatments, and neuro-developmental outcomes. Diagnoses were based on the presence of characteristic compounds detected by amino acid analysis in serum and organic acid analysis in urine. Mutation analysis was performed in the genes of MUT, MMAA, MMAB, and MMACHC for MMA and PCCA and PCCB for PA. Results : Among the 20 patients, six patients were diagnosed before one month of age and nine patients were diagnosed after the newborn period. Five patients were diagnosed via a neonatal screening test. Patients with early-onset forms had more severe illness at presentation and generally poor outcomes. A favorable outcome was obtained in 55% patients; most of them were of a late-onset type or diagnosed by neonatal mass screening test without symptoms. Genotypes were confirmed in all patients with MMA. We detected 11 different mutations by MUT gene analysis in 10 patients, and three different mutations in MMACHC genes in two patients. PCCA and PCCB gene mutations were identified in 14 of the 16 alleles, in eight patients with PA. Conclusion : Organic aciduria is a fatal disease; however, better outcomes are expected whenever early diagnosis and prompt management are made possible. Mutation analysis is useful for confirming diagnoses and planning management strategies.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.557-567
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• 2012

This study was conducted to achieve basal information for the development of tomato cultivars with disease resistances through marker-assisted backcross (MAB). Ten inbred lines with TYLCV, late blight, bacterial wilt, or powdery mildew resistance and four adapted inbred lines with superior horticultural traits were collected, which can be useful as the donor parents and recurrent parents in MAB, respectively. Inbred lines collected were evaluated by molecular markers and bioassay for confirming their disease resistances. To develop DNA markers for selecting recurrent parent genome (background selection) in MAB, a total of 108 simple sequence repeat (SSR) primer sets (nine per chromosome at average) were selected from the tomato reference genetic maps posted on SOL Genomics Network. Genetic similarity and relationships among the inbred lines were assessed using a total of 303 polymorphic SSR markers. Similarity coefficient ranged from 0.33 to 0.80; the highest similarity coefficient (0.80) was found between bacterial wilt-resistant donor lines '10BA333' and '10BA424', and the lowest (0.33) between a late blight resistant-wild species L3708 (S. pimpinelliforium L.) and '10BA424'. UPGMA analysis grouped the inbred lines into three clusters based on the similarity coefficient 0.58. Most of the donor lines of the same resistance were closely related, indicating the possibility that these lines were developed using a common resistance source. Parent combinations (donor parent ${\times}$ recurrent parent) showing appropriate levels of genetic distance and SSR marker polymorphism for MAB were selected based on the dendrogram. These combinations included 'TYR1' ${\times}$ 'RPL1' for TYLCV, '10BA333' or '10BA424' ${\times}$ 'RPL2' for bacterial wilt, and 'KNU12' ${\times}$ 'AV107-4' or 'RPL2' for powdery mildew. For late blight, the wild species resistant line 'L3708' was distantly related to all recurrent parental lines, and a suitable parent combination for MAB was 'L3708' ${\times}$ 'AV107-4', which showed a similarity coefficient of 0.41 and 45 polymorphic SSR markers.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.223-232
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• 2000

Comparative study was performed for the assessment of DNA damage and Chromosomal aberration in human lymphocyte exposed to low dose radiation using fluorescence in situ hybridization(FISH) and single cell gel electrophoresis(SCGE). Chromosomal aberrations in human lymphocytes exposed to radiation at doses of 5, 10, 30 and 50cGy were analysed with whole chromosome-specific probes by human chromosome 1, 2 and 4 according to PAINT system. FISH with chromosome-specific probe has been used to be a valid and rapid method fer detection of chromosome rearrangements induced by low dose radiation. The frequencies of stable translocation per cell equivalents were 0.0116, 0.0375, 0.040f, 0.0727 and 0.0814 for 0, 5, 10, 30 and 50cGy, respectively, and those of dicentric were 0.00, 0.0125, 0.174, 0.0291 and 0.0407 respectively. Radiation induced DNA damage in human lymphocyte in a dose-dependent manner at low doses from 5cGy to 50cGy, which were analysed by single tell gel electrophoresis(SCGE). From above results, FISH seemed to be useful for radiation biodosimetry by which the frequencies of stable aberrations in human lymphocyte can be observed more easily than by conventional method and SCGE also seemed to be sensitive method f9r detecting DNA damage by low dose radiation exposure, so that those methods will improve our technique to perform meaningful biodosimetry for radiation at low doses.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.2
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• pp.113-121
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• 2007

Hearing loss is a common congenital disorder that is frequently associated with mutations in the Cx26 gene (GJB2). Recently, the mutation analysis of GJB2 has been used in a newborn screening test for the detection of hearing impairment. Population-based studies should be performed before the application of genetic testing for the identification of deaf newborns. In this study, 8 positions of GJB2 mutations-including 35delG, 167delT, 235delC, V27I, V37I, M34T, E114G, and I203T-were analyzed using PCR-direct sequencing in a total of 437 healthy Korean neonates. DNAs from dried blood spots were extracted using a commercial DNA extraction kit. The PCR-amplified products (783 bps) of the GJB2 gene were detected using 2% agarose gel electrophoresis and subjected to direct sequencing. The sequences were compared with those in the GenBank database by using the BLAST program. In this study, 5 GJB2 mutations -including V27I (79G>A), V37I (109G>A), E114G (341A>G), I203T (608T>C), and 235delC- were found. Of the 437 neonate samples, 301 subjects showed GJB2 mutations (68.9%, 301/437). The V27I mutation was found in 271 subjects and was the most frequent (62.0%, 271/437). The E114G, I203T and V37I mutations were shown in 146, 17 and 14 subjects, respectively. The 235delC mutation was found in 1 subject. The E114G mutation was frequently accompanied by the V27I mutation. V27I/E114G (97.2%, 143/147) was the most common double mutation and 3 subjects had the double mutation V27I/I203T. A triple mutation, V27I/E114G/I203T, was found in 1 subject. In conclusion, PCR-direct sequencing is a convenient tool for the rapid detection of GJB2 mutations and this data might provide information for the genetic counseling of the GJB2 gene.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.67-73
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• 2005

Photoautotrophic bacteria are promising candidates for the production of poly(3-hydroxybutyrate) (PHB) since they can address the critical problem of substrate costs. In this study, we isolated 25 Tn5-inserted mutants of the Synechocystis sp. PCC 6803 which showed enhanced PHB accumulation compared to the wild-type strain. After 5-days cultivation under nitrogen-limited mixotrophic conditions, the intracellular levels of PHB content in these mutants reached up to $10-30\%$ of dry cell weight (DCW) comparable to $4\%$ of DCW in the wild-type strain. Using the method of inverse PCR, the affected genes of the mutants were mapped on the completely known genome sequence of Synechocystis sp. PCC 6803. As a result, the increased PHB accumulation in 5 mutants were found to be resulted from defects of genes coding for NADH-ubiquinone oxidoreductase, O-succinylbenzoic-CoA ligase, photosystem II PsbT protein or histidine kinase, which are involved in photosystem in thylakoid inner membrane of the cell. The values of $NAD(P)H/NAD(P)^+$ ratio in the cells of these mutants were much higher than that of the wild-type strain as measured by using pulse-amplitude modulated fluorometer, suggesting that PHB synthesis could be enhanced by increasing the level of cellular NAD(P)H which is a limiting substrate for NADPH-dependent acetoacetyl-CoA reductase. From these results, it is likely that NAD(P)H would be a limiting factor for PHB synthesis in Synechocystis sp. PCC 6803.